103 results on '"Makoto Hirota"'
Search Results
2. Optimization of turbulent transition delay effect using quasi-statically transforming wall roughness shape
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Takayuki SHIROSAKI, Makoto HIROTA, and Yuji HATTORI
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swept wing ,crossflow instability ,passive flow control ,boundary layer transition ,laminarization ,Science (General) ,Q1-390 ,Technology - Abstract
Boundary-layer transition on swept wings is dominantly caused by the crossflow instability, which is expected to be suppressed by placing artificial roughness elements near the leading edge. It is however difficult to find the optimal roughness shape by using direct numerical simulation (DNS), because a lot of computations are required for assessing a suppression effect due to one roughness shape. In this study, we develop an efficient method to evaluate the suppression effect for a series of roughness shapes by changing a shape parameter quasi-statically and observing the subsequent change of the crossflow mode at a downstream position. Since the mode grows spatially as convective instability, we need to allow for the delay time for the change in the shape to cause the change in the mode. This method is demonstrated for optimizing the height and angle of sinusoidal roughness elements. By applying a volume penalization (VP) method, the height and angle are changed slowly in DNS, where the initial values, rates of change and permeability of the VP method should be chosen appropriately to reproduce the correct results for the fixed shapes. The method developed here shows that the suppression (or laminarizing) effect tends to be improved as the height is increased, but there is a critical height at which flow tripping occurs. Both the laminarization effect and the critical height vary greatly depending on the angle. This result suggests the optimal roughness shape, considering the effectiveness and robustness. For laminar flow control, this method is useful for optimizing the wall roughness shape.
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- 2022
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3. The Effects of a Biomimetic Hybrid Meso- and Nano-Scale Surface Topography on Blood and Protein Recruitment in a Computational Fluid Dynamics Implant Model
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Hiroaki Kitajima, Makoto Hirota, Kohei Osawa, Toshinori Iwai, Kenji Mitsudo, Juri Saruta, and Takahiro Ogawa
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bone-implant integration ,computational fluid dynamics (CFD) ,osseointegration ,titanium implant ,zirconia implant ,Technology - Abstract
The mechanisms underlying bone-implant integration, or osseointegration, are still incompletely understood, in particular how blood and proteins are recruited to implant surfaces. The objective of this study was to visualize and quantify the flow of blood and the model protein fibrinogen using a computational fluid dynamics (CFD) implant model. Implants with screws were designed with three different surface topographies: (1) amorphous, (2) nano-trabecular, and (3) hybrid meso-spikes and nano-trabeculae. The implant with nano-topography recruited more blood and fibrinogen to the implant interface than the amorphous implant. Implants with hybrid topography further increased recruitment, with particularly efficient recruitment from the thread area to the interface. Blood movement significantly slowed at the implant interface compared with the thread area for all implants. The blood velocity at the interface was 3- and 4-fold lower for the hybrid topography compared with the nano-topography and amorphous surfaces, respectively. Thus, this study for the first time provides insights into how different implant surfaces regulate blood dynamics and the potential advantages of surface texturization in blood and protein recruitment and retention. In particular, co-texturization with a hybrid meso- and nano-topography created the most favorable microenvironment. The established CFD model is simple, low-cost, and expected to be useful for a wide range of studies designing and optimizing implants at the macro and micro levels.
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- 2023
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4. UV photocatalytic activity of titanium dioxide (TiO2) surface contaminated with bacterial biofilm: Implications for photo-restoration of osteoconductivity
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Makoto Hirota, Yoshihiko Sugita, Manabu Ishijima, Takayuki Ikeda, Juri Saruta, Hatsuhiko Maeda, and Takahiro Ogawa
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Photocatalysis ,Titanium dioxide ,Hydrophilicity ,Implant ,Osteoconductivity ,Osteoblast ,Materials of engineering and construction. Mechanics of materials ,TA401-492 - Abstract
Ultraviolet (UV) light-mediated activation of titanium dioxide (TiO2) cleans the surface microenvironment through photocatalysis, but it is unknown whether this occurs when TiO2 surfaces is contaminated with bacterial biofilms. We therefore formed bacterial biofilms on TiO2 surfaces through culture with oral microorganisms from rats, which were subsequently exposed to high-intensity broadband UV light for 12 min. Osteoblast attachment, proliferation, and phenotypes were significantly compromised on biofilm-contaminated TiO2 surfaces, but UV treatment restored these biological activities to native baselines of TiO2 surfaces. The strength of bone-implant integration was 18.3 N for original implants, 1.5 N for biofilm-contaminated implants, and 30.5 N for biofilm-contaminated/UV-treated implants in a rat femur model after two weeks of healing. Histologically, there was limited, fragmented bone formation around biofilm-contaminated implants separated by thick fibrous tissue, while biofilm-contaminated/UV-treated implants induced robust bone formation with extensive direct bone-implant contact. Lipopolysaccharide (LPS) deposited on biofilm-contaminated TiO2 surfaces which was decomposed and removed by UV treatment. Notably, biofilm-contaminated TiO2 surfaces became superhydrophilic after UV treatment despite the persistence of carbon and nitrogen compounds, and UV treatment significantly restored the surface morphology of the innate titanium on the biofilm-contaminated TiO2 surfaces. In summary, bacterial biofilm severely compromised titanium osteoconductivity, but treatment of contaminated titanium with UV light significantly restored osteoconductivity through substantially decreased accumulation of carbon, nitrogen, and LPS; the re-emergence of micro-topography; and the induction of superhydrophilicity, paving the way for photoenergy-mediated debridement of TiO2 surface for clinical benefit.
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- 2021
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5. Ultraviolet Light Treatment of Titanium Microfiber Scaffolds Enhances Osteoblast Recruitment and Osteoconductivity in a Vertical Bone Augmentation Model: 3D UV Photofunctionalization
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Hiroaki Kitajima, Makoto Hirota, Keiji Komatsu, Hitoshi Isono, Takanori Matsuura, Kenji Mitsudo, and Takahiro Ogawa
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UV photofunctionalization ,osteoblasts ,osseointegration ,bone augmentation ,implant ,Cytology ,QH573-671 - Abstract
Vertical bone augmentation to create host bone prior to implant placement is one of the most challenging regenerative procedures. The objective of this study is to evaluate the capacity of a UV-photofunctionalized titanium microfiber scaffold to recruit osteoblasts, generate intra-scaffold bone, and integrate with host bone in a vertical augmentation model with unidirectional, limited blood supply. Scaffolds were fabricated by molding and sintering grade 1 commercially pure titanium microfibers (20 μm diameter) and treated with UVC light (200–280 nm wavelength) emitted from a low-pressure mercury lamp for 20 min immediately before experiments. The scaffolds had an even and dense fiber network with 87% porosity and 20–50 mm inter-fiber distance. Surface carbon reduced from 30% on untreated scaffold to 10% after UV treatment, which corresponded to hydro-repellent to superhydrophilic conversion. Vertical infiltration testing revealed that UV-treated scaffolds absorbed 4-, 14-, and 15-times more blood, water, and glycerol than untreated scaffolds, respectively. In vitro, four-times more osteoblasts attached to UV-treated scaffolds than untreated scaffolds three hours after seeding. On day 2, there were 70% more osteoblasts on UV-treated scaffolds. Fluorescent microscopy visualized confluent osteoblasts on UV-treated microfibers two days after seeding but sparse and separated cells on untreated microfibers. Alkaline phosphatase activity and osteocalcin gene expression were significantly greater in osteoblasts grown on UV-treated microfiber scaffolds. In an in vivo model of vertical augmentation on rat femoral cortical bone, the interfacial strength between innate cortical bone and UV-treated microfiber scaffold after two weeks of healing was double that observed between bone and untreated scaffold. Morphological and chemical analysis confirmed seamless integration of the innate cortical and regenerated bone within microfiber networks for UV-treated scaffolds. These results indicate synergy between titanium microfiber scaffolds and UV photofunctionalization to provide a novel and effective strategy for vertical bone augmentation.
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- 2022
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6. A Novel Cell Delivery System Exploiting Synergy between Fresh Titanium and Fibronectin
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Makoto Hirota, Norio Hori, Yoshihiko Sugita, Takayuki Ikeda, Wonhee Park, Juri Saruta, and Takahiro Ogawa
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biological aging of titanium ,bone engineering ,implants ,osseointegration ,osteoblasts ,Cytology ,QH573-671 - Abstract
Delivering and retaining cells in areas of interest is an ongoing challenge in tissue engineering. Here we introduce a novel approach to fabricate osteoblast-loaded titanium suitable for cell delivery for bone integration, regeneration, and engineering. We hypothesized that titanium age influences the efficiency of protein adsorption and cell loading onto titanium surfaces. Fresh (newly machined) and 1-month-old (aged) commercial grade 4 titanium disks were prepared. Fresh titanium surfaces were hydrophilic, whereas aged surfaces were hydrophobic. Twice the amount of type 1 collagen and fibronectin adsorbed to fresh titanium surfaces than aged titanium surfaces after a short incubation period of three hours, and 2.5-times more fibronectin than collagen adsorbed regardless of titanium age. Rat bone marrow-derived osteoblasts were incubated on protein-adsorbed titanium surfaces for three hours, and osteoblast loading was most efficient on fresh titanium adsorbed with fibronectin. The number of osteoblasts loaded using this synergy between fresh titanium and fibronectin was nine times greater than that on aged titanium with no protein adsorption. The loaded cells were confirmed to be firmly attached and functional. The number of loaded cells was strongly correlated with the amount of protein adsorbed regardless of the protein type, with fibronectin simply more efficiently adsorbed on titanium surfaces than collagen. The role of surface hydrophilicity of fresh titanium surfaces in increasing protein adsorption or cell loading was unclear. The hydrophilicity of protein-adsorbed titanium increased with the amount of protein but was not the primary determinant of cell loading. In conclusion, the osteoblast loading efficiency was dependent on the age of the titanium and the amount of protein adsorption. In addition, the efficiency of protein adsorption was specific to the protein, with fibronectin being much more efficient than collagen. This is a novel strategy to effectively deliver osteoblasts ex vivo and in vivo using titanium as a vehicle.
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- 2022
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7. Pleomorphic Adenoma Arising from Heterotopic Salivary Gland Tissue in the Submandibular Region
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Toshinori Iwai, Satomi Sugiyama, Hiroaki Kitajima, Makoto Hirota, and Kenji Mitsudo
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benign tumour ,chondroid ,myoepithelial ,painless ,Medicine - Published
- 2021
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8. Endoscopically-Assisted Intraoral Resection of Compound Odontoma Arising from the Inferomedial Surface of the Mandibular Ramus using Piezosurgery
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Toshinori Iwai, Satomi Sugiyama, Hiroaki Kitajima, Makoto Hirota, and Kenji Mitsudo
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bone ,endoscope ,mandible ,minimally invasive surgical procedures ,Medicine - Published
- 2020
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9. Endoscopic Removal of a Migrated Fragment of Wire used for Intermaxillary Fixation in Surgical Treatment of Mandibular Fracture
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Toshinori Iwai, Satomi Sugiyama, Toshiyuki Koizumi, Makoto Hirota, and Kenji Mitsudo
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endoscope ,foreign body ,mandible ,Medicine - Published
- 2020
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10. Oral Stings Caused by Sperm Bags of Squid
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Toshinori Iwai, Satomi Sugiyama, Hiroaki Kitajima, Makoto Hirota, and Kenji Mitsudo
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floor of the mouth ,larva ,seafood ,Medicine - Abstract
With the increasing global popularity of Japanese delicacies made of raw seafood, such as sashimi and sushi, sufficient attention should be paid to the conditions caused by raw-food consumption. It is recognised that in ingesting raw squid, bacterial or planktonic toxin, and anisakid larva often cause food-poisoning and anisakiasis, respectively. Oral stings caused by sperm bag of squid are rare. A 21-year-old female had severe pain in her oral cavity immediately after eating a raw squid (Todarodes pacificus), and consulted the department of oral and maxillofacial surgery. Oral examination showed several small whitish, club-shaped foreign bodies stuck in the surface of the floor of mouth and left buccal mucosa. Because the removal with forceps was difficult due to the tight attachment to the mucosa, foreign bodies were removed completely using forceps with slight incisions under local anaesthesia. The stings were diagnosed as a sperm bag of squid.
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- 2020
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11. Endoscopically-assisted intraoral removal of submandibular gland oncocytoma
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Satomi Sugiyama, Toshinori Iwai, Makoto Hirota, and Kenji Mitsudo
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Endoscope ,Intraoral removal ,Oncocytoma ,Submandibular gland ,Dentistry ,RK1-715 - Published
- 2021
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12. Clinical outcomes of retrograde intra-arterial chemotherapy concurrent with radiotherapy for elderly oral squamous cell carcinoma patients aged over 80 years old
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Yuichiro Hayashi, Kenji Mitsudo, Kaname Sakuma, Masaki Iida, Toshinori Iwai, Hideyuki Nakashima, Yoshiyuki Okamoto, Toshiyuki Koizumi, Senri Oguri, Makoto Hirota, Mitomu Kioi, Izumi Koike, Masaharu Hata, and Iwai Tohnai
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Intra-arterial chemotherapy ,Elderly patient ,Head and neck cancer ,Oral cancer ,Radiotherapy ,Medical physics. Medical radiology. Nuclear medicine ,R895-920 ,Neoplasms. Tumors. Oncology. Including cancer and carcinogens ,RC254-282 - Abstract
Abstract Background The aim of this retrospective observational study was to evaluate toxicities, overall survival, and locoregional control in elderly oral squamous cell carcinoma patients who had undergone retrograde intra-arterial chemotherapy combined with radiotherapy. Methods Thirty-one elderly patients over 80 years old with oral squamous cell carcinoma were enrolled in present study. The treatment schedule consisted of intra- arterial chemotherapy (docetaxel, total 60 mg/m2; cisplatin, total 150 mg/m2) and daily concurrent radiotherapy (total, 60 Gy) for 6 weeks. Results The median patient age was 82.5 years old (range, 80–88 years). Of the 31 patients, six (19%) had stage II, 6 (19%) had stage III, 17 (55%) had stage IVA, and 2 (6%) had stage IVB. The median follow-up period for all patients was 37 months (range, 7–86 months). The 3-year overall survival and locoregional control rates were 78% and 81%, respectively. The major acute grade 3 adverse events were oral mucositis in 22 (71%) patients, neutropenia in 16 (52%), and dermatitis in 11 (35%). With respect to late toxicities, 1 patient (3%) developed grade 3 osteoradionecrosis of the jaw. No grade 4 or higher toxicities were observed during the treatment and follow-up periods. Conclusions Retrograde intra-arterial chemotherapy combined with radiotherapy was effective in improving overall survival and locoregional control even for elderly patients.
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- 2017
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13. Preface
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Takashi TOKUMASU, Hitomi ANZAI, Koji FUJITA, Makoto HIROTA, Hisashi NAKAMURA, Koji SHIMOYAMA, and Hidemasa TAKANA
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Science (General) ,Q1-390 ,Technology - Published
- 2019
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14. Ultrasound-Guided Extraoral Removal of Extraparenchymal Sialoliths Caused by Acute Parotitis
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Toshinori Iwai, Satomi Sugiyama, Yuichiro Hayashi, Makoto Hirota, and Kenji Mitsudo
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extraoral approach ,parotid gland ,ultrasonography ,Medicine - Abstract
Migration of sialoliths is extremely rare and is presumed to be a consequence of abscess formation. We report a minimally invasive, ultrasound-guided, extraoral approach for the removal of extraparenchymal sialoliths caused by acute parotitis. A 57-year-old man with left buccal swelling and pain had two parotid sialoliths. Buccal undulation was present after administration of antibiotics, and ultrasound showed extraparenchymal sialoliths. The migrated sialoliths from the parotid gland could be identified easily under ultrasound guidance and removed completely with long mosquito forceps via the small skin incision.
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- 2019
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15. Preface
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Takashi TOKUMASU, Makoto HIROTA, Yuka IGA, Hisashi NAKAMURA, Koji SHIMOYAMA, and Hidemasa TAKANA
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Science (General) ,Q1-390 ,Technology - Published
- 2018
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16. Daily Cisplatin and Weekly Docetaxel versus Weekly Cisplatin Intra-Arterial Chemoradiotherapy for Late T2-3 Tongue Cancer: A Pilot and Feasibility Trial
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Yuichiro Hayashi, Shuhei Minamiyama, Takashi Ohya, Masaki Iida, Toshinori Iwai, Toshiyuki Koizumi, Senri Oguri, Makoto Hirota, Mitomu Kioi, Masaharu Hata, Masataka Taguri, and Kenji Mitsudo
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oral cancer ,radiotherapy ,intra-arterial chemotherapy ,head and neck cancer ,Medicine (General) ,R5-920 - Abstract
Background and objectives: The aim of present study was to compare the treatment results of daily cisplatin (CDDP), weekly docetaxel (DOC) intra-arterial infusion chemotherapy combined with radiotherapy (DIACRT) regimen and weekly CDDP intra-arterial infusion chemotherapy combined with radiotherapy (WIACRT) for patients with tongue cancer. Materials and Methods: Between January 2007 and December 2016, a total of 11 patients treated with WIACRT and 45 patients treated with DIACRT were enrolled in the present study. In the DIACRT group, 25 patients had late T2, and 20 patients had T3. A total of nine patients had late T2 and two had T3 in WIACRT (p = NS). In DIACRT, the treatment schedule consisted of intra-arterial chemotherapy (DOC, total 60 mg/m2; CDDP, total 150 mg/m2) and daily concurrent radiotherapy (RT) (total, 60 Gy). In WIACRT, the treatment schedule consisted of intra-arterial chemotherapy (CDDP, total 360 mg/m2) and daily concurrent RT (total, 60 Gy). Results: The median follow-up periods for DIACRT and WIACRT were 61 and 66 months, respectively. The five-year local control (LC) and overall survival (OS) rate were 94.5% and 89.6% for the DIACRT group, and 60.6% and 63.6% for the WIACRT group, respectively. The LC rate and OS of the DIACRT group were significantly higher than those of the WIACRT group. As regards toxicities, no treatment-related deaths were observed during the follow-up periods in both groups. Conclusions: DIACRT was found to be feasible and effective for patients with tongue cancer and could become a new treatment modality.
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- 2018
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17. Streamwise-Elongated Sinusoidal Roughness Elements with Enhanced Laminarizing Effect on Three-Dimensional Boundary Layer.
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Makoto Hirota, Yuki Ide, and Yuji Hattori
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As a laminar flow control device for delaying the crossflow-induced transition of a three-dimensional boundary layer, sinusoidal roughness elements (SREs) are placed in a Falkner-Skan-Cooke boundary layer, and the resultant laminarizing effect is numerically investigated in comparison with discrete roughness elements (DREs). Because SREs are elongated in the streamwise direction and designed to avoid flow tripping, the critical height of SREs is much higher than that of DREs. Moreover, the wake flow behind SREs efficiently generates and sustains crossflow vortices that are not dangerously unstable against secondary instabilities but able to strongly distort the mean crossflow profile into a less unstable one. By measuring this mean flow distortion by SREs and DREs, the laminarizing effect is compared among them. It is shown that the effect of SREs is higher than that of DREs and can be enhanced by choosing the appropriate height, angle, and wavelength depending on the local boundary-layer profile. [ABSTRACT FROM AUTHOR]
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- 2024
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18. Lagrange Multiplier-Based Optimal Control Technique for Streak Attenuation in High-Speed Boundary Layers
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Omar Es-Sahli, Adrian Sescu, M. Zamir A. Koshuriyan, Yuji Hattori, and Makoto Hirota
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Aerospace Engineering - Abstract
High-amplitude freestream turbulence and surface roughness elements can excite a laminar boundary-layer flow sufficiently to cause streamwise-oriented vortices to develop. These vortices resemble elongated streaks having alternate spanwise variations of the streamwise velocity. Downstream, the vortices “wobble” through an inviscid secondary instability mechanism and, ultimately, transition to turbulence. We formulate an optimal control algorithm to suppress the growth rate of the streamwise vortex system. Considering a high-Reynolds-number asymptotic framework, we reduce the full compressible Navier–Stokes equations to the nonlinear compressible boundary-region equations. We then implement the method of Lagrange multipliers via an appropriate transformation of the original constrained optimization problem into an unconstrained form to obtain the disturbance equations in the form of the adjoint compressible boundary-region equations (ACBREs) and corresponding optimality conditions. Numerical solutions of the ACBRE approach for high-supersonic and hypersonic flows reveal a significant reduction in the kinetic energy and wall shear stress for all considered configurations. We present contour plots to demonstrate the qualitative effect of increased control iterations. Our results indicate that the primary vortex instabilities gradually flatten in the spanwise direction thanks to the ACBRE algorithm.
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- 2023
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19. Stability of Stuart vortices in rotating stratified fluids.
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Yuji Hattori and Makoto Hirota
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ROTATING fluid ,STAGNATION point ,STRAIN rate ,STRATIFIED flow ,MODAL analysis ,VORTEX motion - Abstract
The linear stability of the Stuart vortices, which is a model of arrays of vortices often observed in the atmosphere and the oceans, in rotating stratified fluids is investigated by local and modal stability analysis. As in the case of the two-dimensional (2-D) Taylor-Green vortices, five types of instability appear in general: the pure-hyperbolic instability, the strato-hyperbolic instability, the rotational-hyperbolic instability, the centrifugal instability and the elliptic instability. The condition for each instability and the estimate of the growth rate derived by Hattori & Hirota (J. Fluid Mech., vol. 967, 2023, A32) are shown to also be useful for the Stuart vortices, which supports their applicability to general flows. The properties of each instability depend on stratification and rotation in a way similar to the case of the 2-D Taylor-Green vortices. For the Stuart vortices, however, the centrifugal instability and the elliptic instability become more dominant than the three hyperbolic instabilities in comparison to the 2-D Taylor-Green vortices; this is explained by the larger ratios of the maximum vorticity and the strain rate at the elliptic stagnation points to the strain rate at the hyperbolic stagnation points. Direct correspondence between the modal and local stability results is further established by comparing unstable modes to solutions to the local stability equations; this is useful for identifying the types of modes since the mechanism of instability is readily known in the local stability analysis. This helps us to discover the modes of the ring-type elliptic instability, which have been predicted only theoretically. [ABSTRACT FROM AUTHOR]
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- 2024
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20. A case of Epstein-Barr virus-positive mucocutaneous ulcer in the right tongue that disappeared after treatment for oral candidiasis
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Tomoyo Nozato, Mikio Ozawa, Kenji Mitsudo, Tomomichi Ozawa, Makoto Hirota, and Kohei Osawa
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medicine.medical_specialty ,CD30 ,medicine.diagnostic_test ,business.industry ,Mucocutaneous zone ,Vitiligo ,medicine.disease ,Dermatology ,Pathology and Forensic Medicine ,Discontinuation ,medicine.anatomical_structure ,Otorhinolaryngology ,Tongue ,hemic and lymphatic diseases ,Rheumatoid arthritis ,Biopsy ,medicine ,Surgery ,Methotrexate ,Oral Surgery ,business ,medicine.drug - Abstract
The present report describes a case of Epstein-Barr virus (EBV)-positive mucocutaneous ulcer (EBVMCU) with an ulcerative lesion on the right tongue. A 69-year-old Japanese woman with awareness of pain in the right lingual margin visited our hospital. The patient had rheumatoid arthritis and had been treated with methotrexate (MTX) for 9 years. Vitiligo was found throughout the oral cavity, and ulceration was found on the right tongue. Under a diagnosis of oral candidiasis and suspected right tongue tumor, treatment for candidiasis and biopsy of the right tongue ulcer were performed. Histopathological results were positive for CD20 and CD30 and negative for CD3 and CD5. EBV-encoded small RNA in situ hybridization confirmed positive results in large, atypical cells, suggesting involvement of EBV. EBVMCU was diagnosed based on the history of MTX use associated with rheumatoid arthritis, blood biochemical findings, and histopathological findings. The ulcer on the right tongue margin resolved spontaneously after treatment for oral candidiasis prior to discontinuation of MTX. No recurrence was seen for 18 months.
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- 2022
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21. Optimization of blood and protein flow around superhydrophilic implant surfaces by promoting contact hemodynamics.
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Hiroaki Kitajima, Makoto Hirota, Kohei Osawa, Toshinori Iwai, Juri Saruta, Kenji Mitsudo, and Takahiro Ogawa
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BLOOD proteins ,BLOOD flow ,COMPUTATIONAL fluid dynamics ,BIOLOGICAL interfaces ,HEMODYNAMICS - Abstract
Purpose: We examined blood and protein dynamics potentially influenced by implant threads and hydrophilic/hydrophobic states of implant surfaces. Methods: A computational fluid dynamics model was created for a screw-shaped implant with a water contact angle of 70° (hydrophobic surface) and 0° (superhydrophilic surface). Movements and density of blood and fibrinogen as a representative wound healing protein were visualized and quantified during constant blood inflow. Results: Blood plasma did not occupy 40-50% of the implant interface or the inside of threads around hydrophobic implants, whereas such blood voids were nearly completely eliminated around superhydrophilic implants. Whole blood field vectors were disorganized and random within hydrophobic threads but formed vortex nodes surrounded by stable blood streams along the superhydrophilic implant surface. The averaged vector within threads was away from the implant surface for the hydrophobic implant and towards the implant surface for the superhydrophilic implant. Rapid and massive whole blood influx into the thread zone was only seen for the superhydrophilic implant, whereas a line of conflicting vectors formed at the entrance of the thread area of the hydrophobic implant to prevent blood influx. The fibrinogen density was up to 20-times greater at the superhydrophilic implant interface than the hydrophobic one. Fibrinogen density was higher at the interface than outside the threads only for the superhydrophilic implant. Conclusions: Implant threads and surface hydrophilicity have profound effects on vector and distribution of blood and proteins. Critically, implant threads formed significant biological voids at the interface that were negated by superhydrophilicity- induced contact hemodynamics. [ABSTRACT FROM AUTHOR]
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- 2023
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22. A Novel Orthognathic Surgery With a Half-Millimeter Accuracy for the Maxillary Positioning Using Prebent Plates and Computer-Aided Design and Manufacturing Osteotomy Guide.
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Yosuke Yamashita, Haruki Imai, Hikaru Takasu, Susumu Omura, Koichi Fujita, Toshinori Iwai, Makoto Hirota, and Kenji Mitsudo
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- 2023
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23. Endoscopically-assisted intraoral removal of submandibular gland mucocele
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Kenji Mitsudo, Yasuharu Yajjima, Hiroaki Kitajima, Nobuhide Ohashi, Satomi Sugiyama, Makoto Hirota, Toshinori Iwai, and Yuka Ideta
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medicine.medical_specialty ,business.industry ,Forceps ,Plunging ranula ,Sublingual gland ,Facial artery ,030206 dentistry ,medicine.disease ,Submandibular gland ,Pathology and Forensic Medicine ,Surgery ,03 medical and health sciences ,Dissection ,0302 clinical medicine ,medicine.anatomical_structure ,stomatognathic system ,Otorhinolaryngology ,030220 oncology & carcinogenesis ,medicine.artery ,medicine ,Mucocele ,Oral Surgery ,business ,Lingual nerve - Abstract
Mucoceles originating in submandibular gland (SMG) which are extravasation type are extremely rare. Because the extraoral approach with potential risks of facial nerve injury and scar formation is commonly performed, we report endoscopically-assisted intraoral removal of submandibular gland mucocele as minimally invasive surgery. A 28-year-old female was referred to our department with an eight-week history of left submandibular painless swelling. Radiological diagnosis was not plunging ranula but SMG mucocele. The patient underwent endoscopically-assisted intraoral removal of SMG under general anesthesia as minimally invasive surgery. A mucosal incision on the left oral floor was made. After soft tissues surrounding the SMG were dissected bluntly, the mucocele and SMG were exposed more prominently by digital pressure applied beneath the lower border of the mandible by an assistant. The SMG was gripped with forceps after aspiration of mucocele, and pulled up through the incision by gland dissection. Because the facial artery penetrated the SMG, the facial artery was ligated and cut. The SMG with mucocele was removed completely in intraoral approach. Although there was no continuity with SMG and sublingual gland (SLG), the SLG was also removed preventively. The pathological diagnosis was SMG mucocele. Although lingual nerve paresthesia occurred postoperatively, the paresthesia was recovered completely 3 weeks after surgery. There was no recurrence 2.5 years after surgery. Because intraoral removal of SMG can be performed without cervical scar and facial nerve injury, this intraoral approach with endoscopic assistance can be an alternative to transcervical approach.
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- 2021
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24. Submandibular gland venous malformation with multiple phleboliths
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Nobuhide Ohashi, Makoto Hirota, Toshinori Iwai, Soichiro Ishikawa, Satomi Sugiyama, Shoji Yamanaka, Kenji Mitsudo, and Hiroaki Kitajima
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medicine.medical_specialty ,Panoramic radiograph ,Pathology and Forensic Medicine ,Hemangioma ,Lesion ,03 medical and health sciences ,0302 clinical medicine ,stomatognathic system ,medicine ,Pathological ,business.industry ,030206 dentistry ,Blood flow ,medicine.disease ,Submandibular gland ,stomatognathic diseases ,Lymphatic system ,medicine.anatomical_structure ,Otorhinolaryngology ,030220 oncology & carcinogenesis ,Surgery ,Radiology ,Oral Surgery ,medicine.symptom ,business ,Venous malformation - Abstract
Vascular anomalies in infants and children were separated into hemangiomas and vascular malformations based on their clinical appearance, histopathologic features, and biologic behavior. Whereas vascular malformations are structural abnormalities of capillary, arterial, venous, or lymphatic elements, vascular tumors are characterized by increased endothelial cell turnover. However, misdiagnoses and misperceptions persist around the use of the term "hemangioma". Although venous malformations arising in the submandibular gland are extremely rare, the most have been diagnosed as “hemangioma”. We report a rare submandibular gland venous malformation with multiple phleboliths. A 54-year-old female visited a private dental clinic for the pain of the right mandibular third molar. Panoramic radiograph showed multiple radiopaque lesions below the right mandibular angle. After the diagnosis of submandibular gland stones, she was referred to our department for the treatment. Ultrasonography showed a heterogeneous, hypoechoic lesion with multiple hyperechoic lesions and blood flow in the right submandibular gland. CT showed a well-circumscribed, heterogenous, low-density lesion with multiple calcifications in the right submandibular gland. MRI showed a lesion with signal intensity similar to that of the muscle in the right submandibular gland had multiple low signal intensity lesions on gadolinium-enhanced T1-weighted images. Radiological diagnosis was submandibular gland venous malformation with multiple phleboliths. She underwent intraoral removal of submandibular gland lesion under general anesthesia. Pathological diagnosis was submandibular gland venous malformation with multiple phleboliths.
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- 2021
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25. Temporomandibular joint stability after two types of maxillary impaction surgery in patients with skeletal class II open bite due to condylar deformations: a preliminary study
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Koji Honda, Shuhei Minamiyama, Kenji Mitsudo, Haruki Imai, Yosuke Yamashita, Makoto Hirota, Hikaru Takasu, Takashi Ono, Toshinori Iwai, Koichi Fujita, Susumu Omura, and Risa Usumi-Fujita
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medicine.medical_specialty ,050402 sociology ,business.industry ,Impaction ,medicine.medical_treatment ,05 social sciences ,Orthognathic surgery ,Orthodontics ,030206 dentistry ,Osteoarthritis ,Skeletal class ,medicine.disease ,Condyle ,Temporomandibular joint ,Surgery ,03 medical and health sciences ,0302 clinical medicine ,medicine.anatomical_structure ,0504 sociology ,Autorotation ,medicine ,In patient ,business - Abstract
Purpose: The aim of this study was to evaluate the effect of two types of mandibular autorotation concept (MAC) surgery using maxillary impaction combined with a straight locking miniplate (SLM) te...
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- 2021
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26. Image-guided removal of deeply impacted mandibular third molar using a navigation system
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Nobuhide Ohashi, Toshinori Iwai, Makoto Hirota, Kenji Mitsudo, Satomi Sugiyama, Hiroaki Kitajima, Atsushi Takeda, and Yasuharu Yajima
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Orthodontics ,Panoramic radiograph ,business.industry ,medicine.medical_treatment ,Mandibular fracture ,Mandibular nerve ,Mandible ,Mandibular canal ,030206 dentistry ,Inferior alveolar nerve ,medicine.disease ,Pathology and Forensic Medicine ,stomatognathic diseases ,03 medical and health sciences ,0302 clinical medicine ,medicine.anatomical_structure ,stomatognathic system ,Otorhinolaryngology ,030220 oncology & carcinogenesis ,medicine ,Surgery ,Cortical bone ,Oral Surgery ,business ,Splint (medicine) - Abstract
Conventional intraoral removal of deeply impacted or ectopic mandibular third molar is challenging for limited surgical access. Because there are potential risks of inferior alveolar nerve (IAN) injury or iatrogenic mandibular fracture, several methods for the removal have been proposed. As minimally invasive and safe surgery, we report image-guided removal of deeply impacted mandibular third molar using navigation system. A 32-year-old male was referred to our department with right mandibular pain and swelling. Panoramic radiograph showed right mandibular third molar was deeply impacted and interrupted the white line of the mandibular canal. Computed tomography (CT) showed deep impacted right mandibular third molar with root projection from the lingual cortical bone, and there was resorption of lingual cortical bone and passing of mandibular nerve between roots. For mandibular navigation surgery, a resin occlusal splint with titanium markers and handle was manufactured to fix reference frame to the mandible. CT was performed preoperatively after the occlusal splint was fixed with patient’s mandibular teeth, and the patient underwent image-guided removal of mandibular third molar with navigation system under general anesthesia. After reference frame was attached to the handle of the occlusal splint fixed with patient’s mandibular teeth, point-based registration was performed. The crown was removed after the sectioning, and the root sectioning with calibrated bur was performed carefully to avoid injury of the IAN under navigational guidance. The roots were completely removed, and the IAN was exposed in the lingual cortical bone defect. Postoperative course was uneventful without paresthesia of the IAN.
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- 2020
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27. Response to the comments on ‘Effectiveness of subspinal Le Fort I osteotomy in preventing postoperative nasal deformation’
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Koji Honda, Toshinori Iwai, Yosuke Yamashsita, Hikaru Takasu, Koichi Fujita, Makoto Hirota, Haruki Imai, Kenji Mitsudo, and Susumu Omura
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Orthodontics ,medicine.medical_specialty ,medicine.diagnostic_test ,business.industry ,medicine.medical_treatment ,Computed tomography ,Deformation (meteorology) ,Osteotomy ,Le Fort I osteotomy ,Surgery ,Cephalometry ,medicine ,business - Published
- 2020
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28. Effectiveness of subspinal Le Fort I osteotomy in preventing postoperative nasal deformation
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Makoto Hirota, Toshinori Iwai, Hikaru Takasu, Yosuke Yamashsita, Haruki Imai, Kenji Mitsudo, Koji Honda, Susumu Omura, and Koichi Fujita
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Adult ,Male ,medicine.medical_specialty ,Adolescent ,medicine.medical_treatment ,Computed tomography ,Le Fort I osteotomy ,Young Adult ,03 medical and health sciences ,Imaging, Three-Dimensional ,Postoperative Complications ,0302 clinical medicine ,Suture (anatomy) ,Sagittal Split Ramus Osteotomy ,medicine ,Humans ,Osteotomy, Le Fort ,Reduction (orthopedic surgery) ,Nose ,Retrospective Studies ,Orthodontics ,medicine.diagnostic_test ,business.industry ,Nose Deformities, Acquired ,Soft tissue ,030206 dentistry ,Middle Aged ,Surgery ,Treatment Outcome ,medicine.anatomical_structure ,030220 oncology & carcinogenesis ,Maxilla ,Female ,Tomography, X-Ray Computed ,business - Abstract
Summary Purpose This study sought to determine the effectiveness of subspinal Le Fort I osteotomy (SLFIO) in preventing nasal deformation, by analyzing changes in the nasal profile on three-dimensional computed tomography (3D-CT) images. Patients and methods The participants were 39 Japanese patients with mandibular prognathism (6 men and 33 women) who underwent bilateral sagittal split ramus osteotomy and Le Fort I osteotomy with maxillary advancement: SLFIO was performed in 20 patients and conventional Le Fort I osteotomy (CLFIO) in 19 patients. All patients underwent modified alar base cinch suture, V-Y closure, and reduction of the piriform aperture. CT data acquired before and 1 year after the surgery were evaluated three-dimensionally with software to determine changes in the nasal profile. Results Changes in alar width, alar base width, nasal length, and nasofrontal angle were significantly smaller following SLFIO than following CLFIO, although there were no significant differences in nasal projection, nasal tip angle, or nasolabial angle between two procedures. Conclusion SLFIO for anterior repositioning of the maxilla can prevent undesirable transverse soft tissue changes of the nose.
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- 2020
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29. Coxfa4l3, a novel mitochondrial electron transport chain Complex 4 subunit protein, switches from Coxfa4 during spermatogenesis
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Masahiro Endou, Yasuyuki Kurihara, Kaito Yoshida, Makoto Hirota, Atsumi Sakaguchi, Chika Nakajima, and Naoto Komatsubara
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Male ,Proteomics ,0301 basic medicine ,Gene isoform ,Intracellular localization ,Protein subunit ,Mutually exclusive events ,Cell Line ,Electron Transport Complex IV ,Mice ,03 medical and health sciences ,0302 clinical medicine ,Meiosis ,Animals ,Humans ,Hypoxia ,Spermatogenesis ,Molecular Biology ,Peptide sequence ,Chemistry ,Nuclear Proteins ,Cell Biology ,Electron transport chain ,Cell biology ,HEK293 Cells ,030104 developmental biology ,Organ Specificity ,Molecular Medicine ,030217 neurology & neurosurgery ,HeLa Cells - Abstract
We identified Coxfa4l3, previously called C15orf48 or Nmes1, as a novel accessory protein of Complex IV of the mitochondrial electron transport chain (ETC). Amino acid sequence comparison, the intracellular localization and the protein expression data showed that the protein is the third isoform of Coxfa4 and the expression of Coxfa4 and Coxfa4l3 proteins during spermatogenesis showed a mutually exclusive pattern, implying that Coxfa4 replaces Coxfa4l3 in Complex IV after meiosis. These results may provide some insight into the unique mechanism of ATP production in late spermatogenesis.
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- 2020
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30. Complications of Minimally Invasive Tibial Bone Harvesting: Risk Factors and Treatment.
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Makoto Hirota, Toshinori Iwai, Tomomichi Ozawa, Nobuyuki Mizuki, and Iwai Tohnai
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TREATMENT of surgical complications ,SURGICAL complication risk factors ,ACADEMIC medical centers ,BONE cements ,BONE marrow ,DEBRIDEMENT ,DISEASES ,ORGAN donation ,MINIMALLY invasive procedures ,ORAL surgery ,NEUROLOGICAL disorders ,OSTEOMYELITIS ,POSTOPERATIVE pain ,RISK assessment ,SURGICAL site infections ,TIBIA ,VANCOMYCIN ,RETROSPECTIVE studies ,TREATMENT duration ,METHICILLIN-resistant staphylococcus aureus ,DESCRIPTIVE statistics ,CANCELLOUS bone - Abstract
Purpose: The aim of this retrospective study was to analyze complications, risk factors, and corresponding treatment regarding the medial approach to harvesting tibial bone. Materials and Methods: Consecutive cases at Yokohama City University Hospital were analyzed for complications of tibial particulated bone and marrow harvesting with the medial approach. The condition of bone marrow, duration of harvesting, and complications were evaluated. The complication rate and correlations between bone marrow conditions and duration of bone harvesting were assessed. The corresponding treatments for the complication were also observed. Results: Thirty cases of tibial particulated bone and marrow harvesting for alveolar ridge or sinus floor augmentation before implant therapy from 2005 to 2014 were analyzed. Twenty-one patients had healthy bone marrow, whereas nine patients had fatty bone marrow. The duration of operation in patients who had both spontaneous pain and gait disturbance was approximately 56 minutes, which was significantly longer than that (approximately 40 minutes) in patients who had only gait disturbance (P < .05). A strong correlation between fatty bone marrow condition and bone harvesting time was seen. The correlation between bone marrow condition and bone harvesting time for fatty marrow was stronger than that for healthy marrow with a trend to significant difference (P = .082). The minor and major complication rate was 96.7% and 6.6%, respectively. Two patients showed postoperative infection on the tibial harvesting site. One of them, who had fatty bone marrow, showed methicillin-resistant Staphylococcus aureus--caused osteomyelitis of the tibia, which needed to be debrided and reconstructed with vancomycin-containing bone cement. Conclusion: A duration of less than 40 minutes for harvesting time may decrease the risk of minor complications. Bone marrow condition influenced tibial bone harvesting duration, which may result in increasing the risk of complications. Regarding major complications, it was considered that wound protection was more important even if the marrow condition was healthy. [ABSTRACT FROM AUTHOR]
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- 2019
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31. Bilateral multiple impacted paramolars of the maxilla: A case report
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Tomomichi Ozawa, Tomoyo Nozato, Makoto Hirota, Kenji Mitsudo, Hitoshi Isono, and Rina Nakakaji
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Orthodontics ,Molar ,Supernumerary tooth ,business.industry ,Healthy subjects ,030206 dentistry ,Pathology and Forensic Medicine ,Paramolars ,stomatognathic diseases ,03 medical and health sciences ,0302 clinical medicine ,stomatognathic system ,Otorhinolaryngology ,030220 oncology & carcinogenesis ,Maxilla ,Rare case ,Medicine ,Surgery ,Supernumerary ,Oral Surgery ,business - Abstract
The frequency of supernumerary teeth is approximately 1%. The most frequent site is the anterior maxillary region, and supernumerary molars are relatively rare. Regarding the buccolingual position, most supernumerary teeth appear on the lingual side. The majority of cases present with only one supernumerary tooth, and those with multiple supernumerary teeth often have a genetic disorder. The present report describes a rare case of five impacted supernumerary teeth on the buccal side of bilateral upper molars in a healthy subject. Considering the appearance site and current theories on supernumerary teeth, the teeth were presumed to be impacted paramolars.
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- 2021
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32. Intra-oral minor salivary gland tumors: A pathological study of 131 cases in the Japanese population
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Haruka Yoshii, Kenji Mitsudo, Hiroaki Kitajima, Shuhei Minamiyama, Kohei Osawa, Toshinori Iwai, Makoto Hirota, Satomi Sugiyama, and Yuichiro Hayashi
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Pathology ,medicine.medical_specialty ,Floor of mouth ,Salivary gland ,Adenoid cystic carcinoma ,business.industry ,Basal cell adenocarcinoma ,030206 dentistry ,Japanese population ,medicine.disease ,Pathology and Forensic Medicine ,Pleomorphic adenoma ,03 medical and health sciences ,0302 clinical medicine ,medicine.anatomical_structure ,Otorhinolaryngology ,030220 oncology & carcinogenesis ,Intra oral ,medicine ,Surgery ,Oral Surgery ,business ,Pathological - Abstract
Objective Intra-oral minor salivary gland tumors are relatively rare. This study aimed to clarify the frequency and distribution of intra-oral minor salivary gland tumors in Japanese patients. Methods We retrospectively analyzed the histopathological records of 131 patients with minor salivary gland tumors that were surgically treated between 1967 and 2017 at a single institution. Results Of the 131 minor salivary gland tumors, 61 (47%) were benign and 70 (53%) were malignant. The male:female ratio was 1:1.8 for benign cases and 1:1 for malignant cases. Most of the tumors occurred in the palate, followed by the floor of the mouth. The most frequent minor salivary gland tumor was pleomorphic adenoma among benign tumors and adenoid cystic carcinoma among malignant tumors. The rarest minor salivary gland tumors were Warthin tumors and basal cell adenocarcinoma, accounting for only 0.8% of all cases. Conclusions The present study determined the incidence rates of these rare tumors.
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- 2019
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33. Osteoblast Attachment Compromised by High and Low Temperature of Titanium and Its Restoration by UV Photofunctionalization
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Takahiro Ogawa, Takahisa Okubo, Makoto Hirota, Juri Saruta, Naoki Yanagisawa, Takayuki Ikeda, and Hiroaki Kitajima
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Technology ,implant ,chemistry.chemical_element ,UV treatment ,Rat Bone Marrow ,medicine.disease_cause ,Article ,Superhydrophilicity ,medicine ,General Materials Science ,titanium ,Microscopy ,QC120-168.85 ,Chemistry ,QH201-278.5 ,initial cell attachment ,temperature ,Osteoblast ,Engineering (General). Civil engineering (General) ,TK1-9971 ,medicine.anatomical_structure ,Descriptive and experimental mechanics ,Electrical engineering. Electronics. Nuclear engineering ,Implant ,TA1-2040 ,Ultraviolet ,Uv treatment ,Nuclear chemistry ,Titanium - Abstract
Titanium implants undergo temperature fluctuations during manufacturing, transport, and storage. However, it is unknown how this affects their bioactivity. Herein, we explored how storage (six months, dark conditions) and temperature fluctuations (5–50 °C) affected the bioactivity of titanium implants. Stored and fresh acid-etched titanium disks were exposed to different temperatures for 30 min under wet or dry conditions, and their hydrophilicity/hydrophobicity and bioactivity (using osteoblasts derived from rat bone marrow) were evaluated. Ultraviolet (UV) treatment was evaluated as a method of restoring the bioactivity. The fresh samples were superhydrophilic after holding at 5 or 25 °C under wet or dry conditions, and hydrophilic after holding at 50 °C. In contrast, all the stored samples were hydrophobic. For both fresh and stored samples, exposure to 5 or 50 °C reduced osteoblast attachment compared to holding at 25 °C under both wet and dry conditions. Regression analysis indicated that holding at 31 °C would maximize cell attachment (p <, 0.05). After UV treatment, cell attachment was the same or better than that before temperature fluctuations. Overall, titanium surfaces may have lower bioactivity when the temperature fluctuates by ≥20 °C (particularly toward lower temperatures), independent of the hydrophilicity/hydrophobicity. UV treatment was effective in restoring the temperature-compromised bioactivity.
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- 2021
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34. Effect of Photofunctionalization on Early Implant Failure.
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Makoto Hirota, Tomomichi Ozawa, Toshinori Iwai, Takahiro Ogawa, and Iwai Tohnai
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COMPLICATIONS of prosthesis ,STATISTICS ,OSSEOINTEGRATION ,MULTIPLE regression analysis ,BONE density ,RETROSPECTIVE studies - Abstract
Purpose: This study retrospectively evaluated the effects of bone density, staging strategy, implant stability, healing process, implant length, surface type, and photofunctionalization on early implant failure. Materials and Methods: Consecutive study samples at Yokohama City University Hospital were analyzed for their early implant failure potentially influenced by patient-, surgical protocol-, and implant-related factors. Through the screening process using univariate analysis for those factors, candidate influential factors such as bone density, staging strategy, the level of initial implant stability, postoperative wound breakdown, the length of implants, the surface type of implants, and use or nonuse of photofunctionalization were selected as independent variables in forward multivariate logistic regression analysis. The odds ratio (OR) for candidate factors was calculated. Results: A total of 563 implants placed in 219 patients from 2005 to 2017 were analyzed for their early implant failure. Stepwise logistic regression analysis finally identified postoperative wound breakdown (OR = 0.21) and the use of photofunctionalization (OR = 0.30) that significantly reduced the risk of early implant failure (P < .01 and P < .05, respectively). The implant failure rate was 10.0% with postoperative wound breakdown and 1.0% without it, whereas it was 4.3% without photofunctionalization and 1.3% with it. Conclusion: Among various patient-, surgical protocol-, and implant-related factors, the absence of postoperative wound breakdown and use of photofunctionalization significantly reduced the risk of early implant failure. It was notable that photofunctionalization, a unique, chairside measure to improve implant surfaces, was effective exclusively among implant-related factors. [ABSTRACT FROM AUTHOR]
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- 2018
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35. Compromised Epithelial Cell Attachment after Polishing Titanium Surface and Its Restoration by UV Treatment
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Takahisa Okubo, Naoki Tsukimura, Makoto Hirota, Juri Saruta, Takayuki Ikeda, and Takahiro Ogawa
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Materials science ,Silicon ,implant ,Scanning electron microscope ,chemistry.chemical_element ,Polishing ,UV treatment ,02 engineering and technology ,lcsh:Technology ,prosthetic abutments ,Article ,Contact angle ,Metal ,03 medical and health sciences ,0302 clinical medicine ,X-ray photoelectron spectroscopy ,General Materials Science ,titanium ,Composite material ,lcsh:Microscopy ,attachment ,lcsh:QC120-168.85 ,lcsh:QH201-278.5 ,lcsh:T ,technology, industry, and agriculture ,polished ,030206 dentistry ,respiratory system ,021001 nanoscience & nanotechnology ,equipment and supplies ,humanities ,eye diseases ,chemistry ,lcsh:TA1-2040 ,visual_art ,visual_art.visual_art_medium ,lcsh:Descriptive and experimental mechanics ,lcsh:Electrical engineering. Electronics. Nuclear engineering ,lcsh:Engineering (General). Civil engineering (General) ,0210 nano-technology ,lcsh:TK1-9971 ,Carbon ,human oral epithelial cell ,Titanium - Abstract
Titanium-based implant abutments and tissue bars are polished during the finalization. We hypothesized that polishing degrades the bioactivity of titanium, and, if this is the case, photofunctionalization-grade UV treatment can alleviate the adverse effect. Three groups of titanium disks were prepared, machined surface, polished surface and polished surface followed by UV treatment (polished/UV surface). Polishing was performed by the sequential use of greenstone and silicon rubber burs. UV treatment was performed using a UV device for 12 min. Hydrophobicity/hydrophilicity was examined by the contact angle of ddH2O. The surface morphology and chemistry of titanium were examined by scanning electron microscopy (SEM) and X-ray photoelectron spectroscopy (XPS), respectively. Human epithelium cells were seeded on titanium disks. The number of cells attached, the spreading behavior of cells and the retention on titanium surfaces were examined. The polished surfaces were smooth with only minor scratches, while the machined surfaces showed traces and metal flashes made by machine-turning. The polished surfaces showed a significantly increased percentage of surface carbon compared to machined surfaces. The carbon percentage on polished/UV surfaces was even lower than that on machined surfaces. A silicon element was detected on polished surfaces but not on polished/UV surfaces. Both machined and polished surfaces were hydrophobic, whereas polished/UV surfaces were hydrophilic. The number of attached cells after 24 h of incubation was 60% lower on polished surfaces than on machined surfaces. The number of attached cells on polished/UV surfaces was even higher than that on machined surfaces. The size and perimeter of cells, which was significantly reduced on polished surfaces, were fully restored on polished/UV surfaces. The number of cells remained adherent after mechanical detachment was reduced to half on polished surfaces compared to machined surfaces. The number of adherent cells on polished/UV surfaces was two times higher than on machined surfaces. In conclusion, polishing titanium causes chemical contamination, while smoothing its surface significantly compromised the attachment and retention of human epithelial cells. The UV treatment of polished titanium surfaces reversed these adverse effects and even outperformed the inherent bioactivity of the original titanium.
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- 2020
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36. UV-Pre-Treated and Protein-Adsorbed Titanium Implants Exhibit Enhanced Osteoconductivity
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Makoto Hirota, Takashi Taniyama, Takahiro Ogawa, Takayuki Ikeda, Hiroaki Kitajima, Juri Saruta, and Yoshihiko Sugita
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Male ,Bone Regeneration ,Cell Culture Techniques ,Bone Morphogenetic Protein 2 ,02 engineering and technology ,osteoconductivity ,lcsh:Chemistry ,0302 clinical medicine ,UV-photofunctionalization ,Ultraviolet light ,lcsh:QH301-705.5 ,Spectroscopy ,Cells, Cultured ,Titanium ,biology ,Chemistry ,Osteoblast ,General Medicine ,respiratory system ,021001 nanoscience & nanotechnology ,Computer Science Applications ,medicine.anatomical_structure ,osteoblast ,Alkaline phosphatase ,titanium implants ,0210 nano-technology ,Surface Properties ,Ultraviolet Rays ,chemistry.chemical_element ,Mesenchymal Stem Cell Transplantation ,Bone morphogenetic protein 2 ,Catalysis ,Article ,Inorganic Chemistry ,03 medical and health sciences ,Adsorption ,fibronectin ,mechanical anchorage ,medicine ,Cell Adhesion ,Animals ,Physical and Theoretical Chemistry ,Molecular Biology ,Osteoblasts ,Organic Chemistry ,technology, industry, and agriculture ,Mesenchymal Stem Cells ,030206 dentistry ,Alkaline Phosphatase ,equipment and supplies ,Fibronectins ,Rats ,Fibronectin ,lcsh:Biology (General) ,lcsh:QD1-999 ,Bone Substitutes ,biology.protein ,bone morphogenetic protein-2 ,Nuclear chemistry ,Protein adsorption - Abstract
Titanium materials are essential treatment modalities in the medical field and serve as a tissue engineering scaffold and coating material for medical devices. Thus, there is a significant demand to improve the bioactivity of titanium for therapeutic and experimental purposes. We showed that ultraviolet light (UV)-pre-treatment changed the protein-adsorption ability and subsequent osteoconductivity of titanium. Fibronectin (FN) adsorption on UV-treated titanium was 20% and 30% greater after 1-min and 1-h incubation, respectively, than that of control titanium. After 3-h incubation, FN adsorption on UV-treated titanium remained 30% higher than that on the control. Osteoblasts were cultured on titanium disks after 1-h FN adsorption with or without UV-pre-treatment and on titanium disks without FN adsorption. The number of attached osteoblasts during the early stage of culture was 80% greater on UV-treated and FN-adsorbed (UV/FN) titanium than on FN-adsorbed (FN) titanium, osteoblasts attachment on UV/FN titanium was 2.6- and 2.1-fold greater than that on control- and UV-treated titanium, respectively. The alkaline phosphatase activity of osteoblasts on UV/FN titanium was increased 1.8-, 1.8-, and 2.4-fold compared with that on FN-adsorbed, UV-treated, and control titanium, respectively. The UV/FN implants exhibited 25% and 150% greater in vivo biomechanical strength of bone integration than the FN- and control implants, respectively. Bone morphogenetic protein-2 (BMP-2) adsorption on UV-treated titanium was 4.5-fold greater than that on control titanium after 1-min incubation, resulting in a 4-fold increase in osteoblast attachment. Thus, UV-pre-treatment of titanium accelerated its protein adsorptivity and osteoconductivity, providing a novel strategy for enhancing its bioactivity.
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- 2020
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37. Daily concurrent chemoradiotherapy using retrograde superselective intra-arterial infusion for locally advanced squamous cell carcinoma of the mandibular gingiva
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Toshiyuki Koizumi, Toshinori Iwai, Senri Oguri, Masaharu Hata, Makoto Hirota, Kenji Mitsudo, Iwai Tohnai, Izumi Koike, Masaki Iida, and Mitomu Kioi
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medicine.medical_specialty ,business.industry ,Osteoradionecrosis ,Cancer ,030206 dentistry ,Neutropenia ,medicine.disease ,Pathology and Forensic Medicine ,Surgery ,stomatognathic diseases ,03 medical and health sciences ,0302 clinical medicine ,stomatognathic system ,Otorhinolaryngology ,Docetaxel ,030220 oncology & carcinogenesis ,Carcinoma ,Mucositis ,Medicine ,Oral Surgery ,business ,Adverse effect ,Chemoradiotherapy ,medicine.drug - Abstract
Objective We previously reported that daily concurrent chemoradiotherapy using retrograde superselective intra-arterial infusion for locally advanced oral cancer provided good local control and overall survival rates. This study was performed to evaluate the therapeutic results of daily concurrent intra-arterial chemoradiotherapy for patients with locally advanced squamous cell carcinoma of the mandibular gingiva. Methods Sixteen patients with T3, 4 mandibular gingiva cancer who refused surgery underwent definitive intra-arterial chemoradiotherapy between August 2006 and July 2014. Treatment consisted of concurrent chemoradiotherapy using retrograde superselective intra-arterial infusion (60 Gy, total dose; 60 mg/m2 for docetaxel and 150 mg/m2 for cisplatin). Results Complete response of the primary site was obtained in 14 patients (87.5%). Five-year local control and survival rates were 73.4%and 81.3%, respectively. Grade 3 or 4 toxicities including mucositis and neutropenia were seen in 13 patients (81.3%) and 6 patients (37.5%), respectively. Grade 3 osteoradionecrosis occurred as a late adverse event in 1 patient (6.3%). Conclusions Retrograde daily concurrent intra-arterial chemoradiotherapy for locally advanced carcinoma of the mandibular gingiva provided good local control and overall survival rates. This method can become one of the therapeutic options for patients with locally advanced carcinoma of the mandibular gingiva.
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- 2018
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38. Strato-hyperbolic instability: a new mechanism of instability in stably stratified vortices
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Makoto Hirota, Shota Suzuki, and Yuji Hattori
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Physics ,Mechanical Engineering ,Stratified flows ,Stratification (water) ,Mechanics ,Condensed Matter Physics ,01 natural sciences ,Instability ,010305 fluids & plasmas ,Vortex ,Physics::Fluid Dynamics ,Dipole ,Mechanics of Materials ,Normal mode ,0103 physical sciences ,Streamlines, streaklines, and pathlines ,Parametric oscillator ,010306 general physics - Abstract
The stability of stably stratified vortices is studied by local stability analysis. Three base flows that possess hyperbolic stagnation points are considered: the two-dimensional (2-D) Taylor–Green vortices, the Stuart vortices and the Lamb–Chaplygin dipole. It is shown that the elliptic instability is stabilized by stratification; it is completely stabilized for the 2-D Taylor–Green vortices, while it remains and merges into hyperbolic instability near the boundary or the heteroclinic streamlines connecting the hyperbolic stagnation points for the Stuart vortices and the Lamb–Chaplygin dipole. More importantly, a new instability caused by hyperbolic instability near the hyperbolic stagnation points and phase shift by the internal gravity waves is found; it is named the strato-hyperbolic instability; the underlying mechanism is parametric resonance as unstable band structures appear in contours of the growth rate. A simplified model explains the mechanism and the resonance curves. The growth rate of the strato-hyperbolic instability is comparable to that of the elliptic instability for the 2-D Taylor–Green vortices, while it is smaller for the Stuart vortices and the Lamb–Chaplygin dipole. For the Lamb–Chaplygin dipole, the tripolar instability is found to merge with the strato-hyperbolic instability as stratification becomes strong. The modal stability analysis is also performed for the 2-D Taylor–Green vortices. It is shown that global modes of the strato-hyperbolic instability exist; the structure of an unstable eigenmode is in good agreement with the results obtained by local stability analysis. The strato-hyperbolic mode becomes dominant depending on the parameter values.
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- 2018
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39. Biological and Physicochemical Characteristics of 2 Different Hydrophilic Surfaces Created by Saline-Storage and Ultraviolet Treatment
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Wonhee Park, Amirreza Ghassemi, Makoto Hirota, Masakazu Hasegawa, Manabu Ishijima, D. Douglas Miley, Takeo Sekiya, Kourosh Nakhaei, Yasuyoshi Torii, Takahiro Ogawa, and Naser Mohammadzadeh Rezaei
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Morphology (linguistics) ,Surface Properties ,Ultraviolet Rays ,Scanning electron microscope ,Energy-dispersive X-ray spectroscopy ,chemistry.chemical_element ,02 engineering and technology ,Sodium Chloride ,Mineralization (biology) ,Osseointegration ,03 medical and health sciences ,0302 clinical medicine ,Acid Etching, Dental ,X-ray photoelectron spectroscopy ,Cell Adhesion ,Titanium ,Osteoblasts ,Chemistry ,Photoelectron Spectroscopy ,Spectrometry, X-Ray Emission ,030206 dentistry ,Adhesion ,021001 nanoscience & nanotechnology ,Chemical engineering ,Microscopy, Electron, Scanning ,Oral Surgery ,0210 nano-technology ,Hydrophobic and Hydrophilic Interactions - Abstract
OBJECTIVES Hydrophilicity/hydrophobicity of titanium surfaces may affect osseointegration. Ordinary titanium surfaces are hydrophobic. Recently, 2 different methods of storing titanium in saline solution or treating it with ultraviolet (UV) light were introduced to generate surface hydrophilicity. This study compared biological and physicochemical properties of 2 different hydrophilic titanium surfaces created by these methods. MATERIALS Acid-etched control, saline-stored, and UV-treated titanium surfaces were assessed by scanning electron microscopy, energy dispersive spectroscopy, and x-ray photoelectron spectroscopy. The attachment, spreading behaviors, mineralization, and gene expression of osteoblasts were examined. RESULTS Similar microroughness was found on control and UV-treated surfaces, whereas foreign deposits were observed on saline-stored surfaces. Control and UV-treated surfaces consisted of Ti, O, and C, whereas saline-stored surfaces showed Na and Cl in addition to these 3 elements. Atomic percentage of surface carbon was higher in order of control, saline-stored, and UV-treated surfaces. Osteoblasts cultured on saline-stored surfaces showed higher levels of calcium deposition and collagen I expression than control. Osteoblasts on UV-treated surfaces showed significantly increased levels for all parameters related to cell attachment, cell spreading, the expression of adhesion and cytoskeletal proteins, mineralization, and gene expression compared with control, outperforming saline-stored surfaces for most parameters. CONCLUSION Despite similar hydrophilicity, saline-stored and UV light-treated surfaces showed substantially different biological effects on osseointegration, associated with different surface chemistry and morphology.
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- 2018
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40. Hemangiopericytoma/solitary fibrous tumor of the buccal mucosa: A case report
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Makoto Hirota, Naoko Udaka, Toshinori Iwai, Shuhei Minamiyama, Tomomichi Ozawa, and Kenji Mitsudo
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Hemangiopericytoma ,Pathology ,medicine.medical_specialty ,Solitary fibrous tumor ,Mitotic index ,business.industry ,030206 dentistry ,Malignancy ,medicine.disease ,Pathology and Forensic Medicine ,Metastasis ,Lesion ,Hemangioma ,03 medical and health sciences ,0302 clinical medicine ,Otorhinolaryngology ,030220 oncology & carcinogenesis ,Medicine ,Surgery ,Oral Surgery ,medicine.symptom ,business ,Immunostaining - Abstract
Hemangiopericytoma/solitary fibrous tumor (HPC/SFT) is a perivascular mesenchymal tumor often found unexpectedly on histopathological examination, and occasionally shows malignant behavior. The incidence of intraoral HPC/SFT is extremely rare. We report a case of HPC/SFT located in the buccal mucosa. A 50-year-old woman presented with a 5-year history of a painless mass in the left buccal mucosa. Clinical findings showed the lesion was a well-defined tumor between the cheek skin and buccal mucosa with two feeding arteries, indicating hemangioma. The tumor was completely resected under general anesthesia. Histopathologically, immunostaining for STAT6 revealed results consistent with HPC/SFT, and no findings suggestive of malignancy, such as tumor size greater than 5 cm and high proliferative activity as shown by mitotic index and Ki-67 index. No other distinct primary lesion or distant metastasis was detected on whole-body computed tomography. Dealing with the lesion as a precancerous or potentially malignant tumor, follow-up was performed for 5 years after surgery, but neither recurrence nor metastasis was observed. As recurrence or metastasis may be delayed by many years, follow-up needs to be continued long-term according to risk factors of malignant behavior such as tumor size, cell characteristics and proliferative activity.
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- 2019
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41. Role of 18F-fluorodeoxyglucose positron emission tomography/computed tomography in predicting pathological response to preoperative super-selective intra-arterial chemoradiotherapy for advanced squamous cell carcinoma of the mandible
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Yukihiko Ozawa, Makoto Hirota, Toshinori Iwai, Senri Oguri, Iwai Tohnai, Maiko Shibasaki, Toshiyuki Koizumi, and Kenji Mitsudo
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PET-CT ,medicine.diagnostic_test ,business.industry ,PET/CT ,Mandible ,Pathological response ,Standardized uptake value ,030218 nuclear medicine & medical imaging ,Lesion ,Intra-arterial chemoradiotherapy ,03 medical and health sciences ,0302 clinical medicine ,Oncology ,Positron emission tomography ,030220 oncology & carcinogenesis ,Squamous cell carcinoma ,medicine ,medicine.symptom ,business ,Nuclear medicine ,Pathological ,Chemoradiotherapy ,Research Article - Abstract
Introduction Although chemoradiotherapy (CRT) for oral squamous cell carcinoma (SCC) has been shown to preserve organ function and improve cosmetic results, site-specific data, especially mandible, are limited. The aim of this study was to evaluate the predictability of 18F-fluorodeoxyglucose positron emission tomography/computed tomography (FDG-PET/CT) on response to super-selective intra-arterial CRT for advanced SCC of the mandible. Methods Fifteen patients with advanced SCC of the mandible underwent super-selective intra-arterial CRT followed by radical resection. Maximum standardized uptake value (SUVmax) of the mandibular lesion was evaluated with FDG-PET/CT before and after CRT. The SUVmax before and after CRT was defined as pre-SUVmax and post-SUVmax, respectively. The difference between pre- and post-SUVmax was calculated as SUVmax reduction rate to evaluate treatment response of the mandibular lesion. Each SUVmax reduction rate and surgical specimen of the corresponding lesion was analyzed to evaluate an accuracy of the modality for predicting pathological response. Results The median of pre-SUVmax was significantly lower than that of post-SUVmax (p = 0.001). Of the 15 patients, 6 had a pathological complete response (pCR) and 9 had a non-pCR. Neither pCR patients nor non-pCR patients showed significant difference of the median of SUVmax between pre- and post-CRT (pre-CRT p = 0.099 post-CRT p =0.074). The SUVmax reduction rate in patients with pCR was significantly higher than that with non-pCR (p = 0.002). Receiver operating characteristic analysis revealed that the optimal cut-off point of the reduction rate was 64.7%, with 83% sensitivity and 100% specificity. Conclusions These results concluded that SUVmax reduction rate can predict pathological complete response of preoperative super-selective intra-arterial CRT for advanced SCC of the mandible.
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- 2018
42. Actinomyces -associated calcifications around an impacted third molar of the mandible
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Kenji Mitsudo, Maiko Shibasaki, Hiroshi Chikumaru, Toshinori Iwai, Takashi Hibiya, Iwai Tohnai, Kenichi Ohashi, and Makoto Hirota
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Molar ,Panoramic radiograph ,Dentistry ,Pathology and Forensic Medicine ,Mandibular second molar ,03 medical and health sciences ,0302 clinical medicine ,stomatognathic system ,medicine ,biology ,business.industry ,Mandible ,Soft tissue ,030206 dentistry ,Anatomy ,medicine.disease ,biology.organism_classification ,stomatognathic diseases ,030228 respiratory system ,Otorhinolaryngology ,Surgery ,Actinomycosis ,Oral Surgery ,business ,Actinomyces ,Calcification - Abstract
Actinomycosis is often considered an affliction of the soft tissues, but in fact, the process spreads to bone in up to 15% of cases. Although Actinomyces -associated lesions in the jaw, such as radicular cyst and osteomyelitis, have been reported by many authors, there are few reports have previously described Actinomyces -associated calcification in the jaw. We report here a rare case of Actinomyces -associated calcifications around an impacted third molar of the mandible. A 76-year-old man with left mandibular pericoronitis was referred to our department. A panoramic radiograph showed alveolar bone resorption caused by severe periodontitis of the left mandibular second molar and multiple small radiopaque spots around the crown of left mandibular third molar in a radiolucent lesion. Computed tomography revealed that the lesion of the left mandibular retromolar lesion was low density, with multiple high density spots surrounding the third molar crown surface. Removal of the lesion and the left mandibular second and third molars were performed and multiple small black pieces of hard tissue were present on the crown surface of the third molar. Histopathological examination of soft tissue specimen around the third molar revealed that collagenous fibroconnective tissue infiltrated by inflammatory cells with squamous epithelium on its surface. Black hard tissue consisted of calcification and conglomerations of Actinomyces which were densely stained by hematoxylin-eosin stain were observed at the margin of the hard tissue surrounding tiny filamentous structures. The postoperative course was uneventful without need for additional antibiotics and there has been no recurrence 22 months after surgery.
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- 2017
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43. Novel Osteogenic Behaviors around Hydrophilic and Radical-Free 4-META/MMA-TBB: Implications of an Osseointegrating Bone Cement
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Chika Iwasaki, Takahisa Okubo, Juri Saruta, Masaichi-Chang-il Lee, Makiko Saita, Makoto Hirota, Masakazu Hasegawa, Yasuyoshi Torii, Wonhee Park, Yoshihiko Sugita, Takashi Taniyama, Takahiro Ogawa, Manabu Ishijima, Naser Mohammadzadeh Rezaei, Hatsuhiko Maeda, Miyuki Tanaka, Takeo Sekiya, Masako Tabuchi, and Nobuaki Sato
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Male ,Bone Regeneration ,Arthroplasty, Replacement, Hip ,implants ,Biocompatible Materials ,02 engineering and technology ,Polymerization ,lcsh:Chemistry ,Rats, Sprague-Dawley ,chemistry.chemical_compound ,0302 clinical medicine ,Osteogenesis ,Materials Testing ,Methylmethacrylates ,Methyl methacrylate ,Boranes ,Cytotoxicity ,lcsh:QH301-705.5 ,Spectroscopy ,Chemistry ,Bone Cements ,food and beverages ,Prostheses and Implants ,General Medicine ,021001 nanoscience & nanotechnology ,Bone cement ,PMMA ,Computer Science Applications ,Phenotype ,Monomer ,Methacrylates ,cytotoxicity ,0210 nano-technology ,Hydrophobic and Hydrophilic Interactions ,medicine.drug ,Boron Compounds ,Free Radicals ,Cell Survival ,Bone Marrow Cells ,Benzoyl peroxide ,Methylmethacrylate ,Bone and Bones ,Article ,Catalysis ,Cell Line ,Inorganic Chemistry ,03 medical and health sciences ,Calcification, Physiologic ,medicine ,Animals ,Polymethyl Methacrylate ,Physical and Theoretical Chemistry ,Molecular Biology ,free radical ,Osteoblasts ,Organic Chemistry ,technology, industry, and agriculture ,030206 dentistry ,equipment and supplies ,Rats ,total hip replacement ,lcsh:Biology (General) ,lcsh:QD1-999 ,arthroplasty ,Implant ,Cysteine ,Nuclear chemistry - Abstract
Poly(methyl methacrylate) (PMMA)-based bone cement, which is widely used to affix orthopedic metallic implants, is considered bio-tolerant but lacks osteoconductivity and is cytotoxic. Implant loosening and toxic complications are significant and recognized problems. Here we devised two strategies to improve PMMA-based bone cement: (1) adding 4-methacryloyloxylethyl trimellitate anhydride (4-META) to MMA monomer to render it hydrophilic, and (2) using tri-n-butyl borane (TBB) as a polymerization initiator instead of benzoyl peroxide (BPO) to reduce free radical production. Rat bone marrow-derived osteoblasts were cultured on PMMA-BPO, common bone cement ingredients, and 4-META/MMA-TBB, newly formulated ingredients. After 24 h of incubation, more cells survived on 4-META/MMA-TBB than on PMMA-BPO. The mineralized area was 20-times greater on 4-META/MMA-TBB than PMMA-BPO at the later culture stage and was accompanied by upregulated osteogenic gene expression. The strength of bone-to-cement integration in rat femurs was 4- and 7-times greater for 4-META/MMA-TBB than PMMA-BPO during early- and late-stage healing, respectively. MicroCT and histomorphometric analyses revealed contact osteogenesis exclusively around 4-META/MMA-TBB, with minimal soft tissue interposition. Hydrophilicity of 4-META/MMA-TBB was sustained for 24 h, particularly under wet conditions, whereas PMMA-BPO was hydrophobic immediately after mixing and was unaffected by time or condition. Electron spin resonance (ESR) spectroscopy revealed that the free radical production for 4-META/MMA-TBB was 1/10 to 1/20 that of PMMA-BPO within 24 h, and the substantial difference persisted for at least 10 days. The compromised ability of PMMA-BPO in recruiting cells was substantially alleviated by adding free radical-scavenging amino-acid N-acetyl cysteine (NAC) into the material, whereas adding NAC did not affect the ability of 4-META/MMA-TBB. These results suggest that 4-META/MMA-TBB shows significantly reduced cytotoxicity compared to PMMA-BPO and induces osteoconductivity due to uniquely created hydrophilic and radical-free interface. Further pre-clinical and clinical validations are warranted.
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- 2020
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44. Airway obstruction caused by pharyngolaryngeal swelling after intraoral removal of a submandibular gland stone
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Satomi Sugiyama, Kenji Mitsudo, Senri Oguri, Toshinori Iwai, Nobuhide Ohashi, and Makoto Hirota
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medicine.medical_specialty ,Case Report ,complication ,03 medical and health sciences ,0302 clinical medicine ,stomatognathic system ,Medicine ,Pharmacology (medical) ,General Pharmacology, Toxicology and Pharmaceutics ,030223 otorhinolaryngology ,airway obstruction ,sialolithiasis ,submandibular gland stone ,Chemical Health and Safety ,business.industry ,Potential risk ,Left submandibular gland ,intraoral removal ,General Medicine ,Airway obstruction ,medicine.disease ,Submandibular gland ,Surgery ,medicine.anatomical_structure ,030220 oncology & carcinogenesis ,Stone removal ,Swelling ,medicine.symptom ,Complication ,business ,Airway ,Safety Research - Abstract
Intraoral removal of a submandibular gland stone is less invasive than submandibulectomy, with no life-threatening airway complications reported until now. We report a case involving airway obstruction caused by pharyngolaryngeal swelling after intraoral removal of a submandibular gland stone. A 31-year-old man with a left submandibular gland stone underwent intraoral removal of the stone under general anesthesia and was discharged 1 day after surgery. That night, he was transported back to our hospital by ambulance for dyspnea. Because computed tomography showed pharyngolaryngeal swelling, he was intubated and managed by a ventilator. Four days later, the pharyngolaryngeal swelling had mostly resolved and he was extubated and discharged. Surgeons should be vigilant of the potential risk of airway complications following an intraoral approach for submandibular gland stone removal.
- Published
- 2018
45. Peripheral osteoma arising from the lateral surface of the mandibular ramus
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Kohei Osawa, Toshinori Iwai, Hiroaki Kitajima, Junichi Baba, Iwai Tohnai, Makoto Hirota, Satomi Sugiyama, and Senri Oguri
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Facial trauma ,Periosteum ,business.industry ,030206 dentistry ,Anatomy ,medicine.disease ,Trismus ,030218 nuclear medicine & medical imaging ,Pathology and Forensic Medicine ,Temporomandibular joint ,body regions ,Lesion ,Masseter muscle ,03 medical and health sciences ,0302 clinical medicine ,medicine.anatomical_structure ,stomatognathic system ,Otorhinolaryngology ,medicine ,Surgery ,Oral Surgery ,medicine.symptom ,business ,Osteoma ,Facial symmetry - Abstract
Osteomas are benign, slow-growing osteogenic tumors that consist of compact or cancellous bone. They sometimes arise from the craniomaxillofacial region. Among the peripheral, central, and extraskeletal types, peripheral osteomas arise from the periosteum, usually as unilateral, pedunculated, mushroom-like masses. Here, we report an unusual peripheral osteoma arising from the lateral surface of the mandibular ramus. A 57-year-old woman with a mass at the left mandibular ramus was referred to us. The hard and immobile mass had been growing for 15 years, and she had facial asymmetry. She had no trismus, temporomandibular joint dysfunction, previous facial trauma, or infection. Computed tomography showed a mushroom-like lesion (21.1 × 13.4 × 13.1 mm) arising from the lateral surface of the left mandibular ramus. Clinical diagnosis was peripheral osteoma. The lesion was removed using rotary instruments and a chisel through an intraoral approach under general anesthesia. The lesion had intruded into the masseter muscle. Pathological diagnosis was compact osteoma. The postoperative course was uneventful and there has been no recurrence 1.5 years after surgery.
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- 2018
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46. Orthognathic Surgery and Implant-Supported Bridge in a Class III Patient Injured in a Motor Vehicle Accident
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Iwai Tohnai, Makoto Hirota, Koji Honda, Toshinori Iwai, Takashi Ono, Koichi Fujita, and Susumu Omura
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Adult ,Male ,medicine.medical_treatment ,Orthognathic surgery ,03 medical and health sciences ,Orthognathic Surgical Procedures ,0302 clinical medicine ,stomatognathic system ,Occlusion ,Maxilla ,medicine ,Humans ,Jaw, Edentulous ,Bridge (dentistry) ,Dental implant ,Anterior teeth ,Dental Implants ,Orthodontics ,Bone Transplantation ,business.industry ,Accidents, Traffic ,030206 dentistry ,General Medicine ,stomatognathic diseases ,Dental arch ,medicine.anatomical_structure ,Otorhinolaryngology ,030220 oncology & carcinogenesis ,Surgery ,business - Abstract
Occlusal and esthetic rehabilitation of jaw deformities in patients with partially edentulous maxilla are challenging procedures. This article describes a patient involving a skeletal Class III, 36-year-old male patient with a single bilateral anterior partially edentulous maxilla resulting from injuries sustained in a motor vehicle accident; his anterior teeth had been lost for more than 10 years. His lip protruded from the lateral view due to the proclined upper incisors and mandibular protrusion.Because of the facial deformity and inadequate prosthesis of the maxilla, the prosthesis had dropped out repeatedly. Bone deficiency was prominent in the area of the anterior maxillary region and required augmentation for implant restoration.Consultation among the prosthodontist, orthodontist, and patient led to a decision to perform an orthognathic surgery and bone graft before implant treatment. After orthodontic treatment combined with orthognathic surgery, 3 dental implants were placed with simultaneous iliac bone graft for prosthetic rehabilitation. The treatment restored the maxillary dental arch, which supported the upper lip with appropriate occlusion, both esthetically and functionally. After a 2-year clinical follow-up, the orthoprosthesis of the maxilla remained stable, and the patient was satisfied with the outcome of treatment. The combination of orthodontic, surgical, and dental implant treatment could be an option for skeletal Class III patients with bone-deficient, edentulous jaws.
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- 2018
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47. Disproportionate Effect of Sub-Micron Topography on Osteoconductive Capability of Titanium
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Nobuaki Sato, Juri Saruta, Takahisa Okubo, Takahiro Ogawa, Makoto Hirota, and Manabu Ishijima
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life_sciences_other ,Male ,02 engineering and technology ,Surface finish ,Calcium deposition ,Rats, Sprague-Dawley ,lcsh:Chemistry ,Osteoblast function ,0302 clinical medicine ,bone regeneration ,lcsh:QH301-705.5 ,Cells, Cultured ,Spectroscopy ,Titanium ,orthopedic implants ,General Medicine ,021001 nanoscience & nanotechnology ,bone integration ,Computer Science Applications ,sub-micro-rough ,0210 nano-technology ,Materials science ,chemistry.chemical_element ,micro-rough ,Article ,Catalysis ,Osseointegration ,Inorganic Chemistry ,03 medical and health sciences ,In vivo ,dental implants ,Bone-Implant Interface ,Animals ,Femur ,Physical and Theoretical Chemistry ,Bone regeneration ,Molecular Biology ,Cell Proliferation ,Osteoblasts ,Organic Chemistry ,osseointegration ,acid-etching ,030206 dentistry ,Rats ,chemistry ,lcsh:Biology (General) ,lcsh:QD1-999 ,Implant ,Biomedical engineering - Abstract
Titanium micro-scale topography offers excellent osteoconductivity and bone&ndash, implant integration. However, the biological effects of sub-micron topography are unknown. We compared osteoblastic phenotypes and in vivo bone and implant integration abilities between titanium surfaces with micro- (1&ndash, 5 µ, m) and sub-micro-scale (0.1&ndash, 0.5 µ, m) compartmental structures and machined titanium. The calculated average roughness was 12.5 ±, 0.65, 123 ±, 6.15, and 24 ±, 1.2 nm for machined, micro-rough, and sub-micro-rough surfaces, respectively. In culture studies using bone marrow-derived osteoblasts, the micro-rough surface showed the lowest proliferation and fewest cells attaching during the initial stage. Calcium deposition and expression of osteoblastic genes were highest on the sub-micro-rough surface. The bone&ndash, implant integration in the Sprague&ndash, Dawley male rat femur model was the strongest on the micro-rough surface. Thus, the biological effects of titanium surfaces are not necessarily proportional to the degree of roughness in osteoblastic cultures or in vivo. Sub-micro-rough titanium ameliorates the disadvantage of micro-rough titanium by restoring cell attachment and proliferation. However, bone integration and the ability to retain cells are compromised due to its lower interfacial mechanical locking. This is the first report on sub-micron topography on a titanium surface promoting osteoblast function with minimal osseointegration.
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- 2019
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48. Effects of Ultraviolet Photofunctionalization on Bone Augmentation and Integration Capabilities of Titanium Mesh and Implants.
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Makoto Hirota, Takayuki Ikeda, Masako Tabuchi, Tomomichi Ozawa, Iwai Tohnai, and Takahiro Ogawa
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THERAPEUTIC use of ultraviolet radiation ,OSSEOINTEGRATION ,TITANIUM ,TISSUE engineering ,DENTAL implants ,THERAPEUTICS ,BONES ,FEMUR - Abstract
Purpose: Ultraviolet (UV)-mediated photofunctionalization has earned considerable attention for the enhancement of the biologic capabilities of titanium. The effects of photofunctionalization on bone augmentation and gap closure were examined using titanium implants and mesh in a rat femur model. Materials and Methods: An acid-etched titanium implant (4-mm length, 1-mm diameter) was placed in the gluteal tuberosity that resembles a knife-edge–like edentulous ridge. The lower half of the implant was located in a 2-mm-diameter defect created in the bone without cortical bone support; the upper half was exposed and covered with a titanium mesh to provide augmentation space. After 12 and 24 days of healing, specimens were subjected to microcomputed tomography (micro-CT)- and histology-based bone morphometry in three zones of analysis: augmentation, cortical bone-implant gap, and bone marrow. A biomechanical push-in test was performed to examine the strength of bone-implant integration. Photofunctionalization was performed by treating titanium implants and mesh with UV light for 12 minutes. Results: Photofunctionalized titanium mesh and implants were hydrophilic, whereas untreated controls were hydrophobic. Bone volume was significantly greater in photofunctionalized implants and mesh than in untreated implants in all zones on days 12 and 24. Bone-to-implant contact of photofunctionalized implants was greater than that of untreated implants, not just in the bone marrow but also in the gap and augmented zones. The strength of osseointegration was three times greater for photofunctionalized implants than for untreated implants. Conclusion: Use of photofunctionalized titanium mesh and implants effectively enhanced vertical bone augmentation, cortical bone-implant gap closure, and osseointegration without innate bone support. [ABSTRACT FROM AUTHOR]
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- 2017
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49. Biomimetic Zirconia with Cactus-Inspired Meso-Scale Spikes and Nano-Trabeculae for Enhanced Bone Integration
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Ryotaro Ozawa, Hiroaki Kitajima, Makoto Hirota, Juri Saruta, Manabu Ishijima, Takahisa Okubo, Samira Rahim Taleghani, and Takahiro Ogawa
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Cactaceae ,Male ,dental and orthopedic implant ,Materials science ,QH301-705.5 ,laser etching ,Y-TZP ,Laser etching ,02 engineering and technology ,Surface finish ,Engraving ,Article ,Catalysis ,Rats, Sprague-Dawley ,Inorganic Chemistry ,Meso scale ,bone-implant integration ,03 medical and health sciences ,Biomimetic Materials ,Osteogenesis ,Nano ,medicine ,Animals ,Cubic zirconia ,Biology (General) ,Physical and Theoretical Chemistry ,QD1-999 ,Molecular Biology ,Spectroscopy ,030304 developmental biology ,0303 health sciences ,Osteoblasts ,Organic Chemistry ,Biomaterial ,Cell Differentiation ,Osteoblast ,General Medicine ,021001 nanoscience & nanotechnology ,Nanostructures ,Rats ,Computer Science Applications ,Chemistry ,medicine.anatomical_structure ,visual_art ,visual_art.visual_art_medium ,Zirconium ,0210 nano-technology ,Biomedical engineering - Abstract
Biomimetic design provides novel opportunities for enhancing and functionalizing biomaterials. Here we created a zirconia surface with cactus-inspired meso-scale spikes and bone-inspired nano-scale trabecular architecture and examined its biological activity in bone generation and integration. Crisscrossing laser etching successfully engraved 60 μm wide, cactus-inspired spikes on yttria-stabilized tetragonal zirconia polycrystal (Y-TZP) with 200–300 nm trabecular bone-inspired interwoven structures on the entire surface. The height of the spikes was varied from 20 to 80 μm for optimization. Average roughness (Sa) increased from 0.10 μm (polished smooth surface) to 18.14 μm (80 μm-high spikes), while the surface area increased by up to 4.43 times. The measured dimensions of the spikes almost perfectly correlated with their estimated dimensions (R2 = 0.998). The dimensional error of forming the architecture was 1% as a coefficient of variation. Bone marrow-derived osteoblasts were cultured on a polished surface and on meso- and nano-scale hybrid textured surfaces with different spike heights. The osteoblastic differentiation was significantly promoted on the hybrid-textured surfaces compared with the polished surface, and among them the hybrid-textured surface with 40 μm-high spikes showed unparalleled performance. In vivo bone-implant integration also peaked when the hybrid-textured surface had 40 μm-high spikes. The relationships between the spike height and measures of osteoblast differentiation and the strength of bone and implant integration were non-linear. The controllable creation of meso- and nano-scale hybrid biomimetic surfaces established in this study may provide a novel technological platform and design strategy for future development of biomaterial surfaces to improve bone integration and regeneration.
- Published
- 2021
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50. Bone Generation Profiling Around Photofunctionalized Titanium Mesh.
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Makoto Hirota, Takayuki Ikeda, Masako Tabuchi, Kaori Nakagawa, Wonhee Park, Manabu Ishijima, Naoki Tsukimura, Yoshiyuki Hagiwara, and Takahiro Ogawa
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SURGICAL equipment ,ALKALINE phosphatase ,ANIMAL experimentation ,BONE regeneration ,CELL culture ,COLORIMETRY ,COMPUTED tomography ,ENZYME-linked immunosorbent assay ,DENTAL implants ,RATS ,RESEARCH funding ,SCANNING electron microscopy ,T-test (Statistics) ,TITANIUM ,X-ray spectroscopy ,THREE-dimensional imaging ,DATA analysis software ,DESCRIPTIVE statistics - Abstract
Purpose: The aim of this study was to evaluate whether photofunctionalization of titanium mesh enhances its osteoconductive capability. Materials and Methods: The titanium mesh (0.2 mm thickness) used in this study was made of commercially pure grade-2 titanium and had hexagonal apertures (2 mm width). Photofunctionalization was performed by treating titanium mesh with UV light for 12 minutes using a photo device immediately before use. Untreated or photofunctionalized titanium mesh was placed into rat femurs, and bone generation around titanium mesh was profiled using three-dimensional (3D) microcomputed tomography (micro-CT). A set of in vitro experiments was conducted using bone marrow-derived osteoblasts. Results: Photofunctionalized titanium mesh surfaces were characterized by the regenerated hydrophilicity and significantly reduced surface carbon. Bone generation profiling at week 3 of healing showed that the hexagonal apertures in photofunctionalized mesh were 95% filled, but they were only 57% filled in untreated mesh, particularly with the center zone remaining as a gap. Bone profiling in slices parallel to the titanium surface showed that photofunctionalized titanium mesh achieved 90% bone occupancy 0 to 400 μm from the surface, compared with only 35% for untreated mesh. Bone occupancy remained as high as 55% 800 to 1,200 μm from photofunctionalized titanium mesh surfaces, compared with less than 20% for untreated mesh. In vitro, photofunctionalized titanium mesh expedited and enhanced attachment and spread of osteoblasts, and increased ALP activity and the rate of mineralization. Conclusion: This study may provide novel and advanced metrics describing the osteoconductive property of photofunctionalized titanium mesh. Specifically, photofunctionalization not only increased the breadth, but also the 3D range, of osteoconductivity of titanium mesh, enabling space-filling and far-reaching osteoconductivity. Further translational and clinical studies are warranted to establish photofunctionalized titanium mesh as a novel clinical tool for better bone regeneration and augmentation. [ABSTRACT FROM AUTHOR]
- Published
- 2016
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