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Background/purpose: The chemo-mechanical caries-removal technique is known to offer advantages of selective dentin caries treatment while leaving healthy dental tissues intact. However, current sodium hypochlorite based reagents usually excessively damage dentin collagen. Therefore, the purpose of this study was to develop a novel chemo-mechanical caries-removal system to preserve the collagen network for subsequent prosthetic restorations. Materials and methods: The calfskin-derived collagen was chosen as a model system to investigate the dissolution behavior of collagen under different operating conditions of chemical-ultrasonic treatment systems. The molecular weight, triple-helix structure, the morphology, and functional group of collagen after treatment were investigated. Results: Various concentrations of sodium hypochlorite or zinc chloride together with ultrasonic machinery were chosen to investigate. The outcomes of circular dichroism (CD) spectra demonstrated stability of the triple-helix structure after treatment of a zinc chloride solution. In addition, two apparent bands at molecular weights (MWs) of 130 and 121 kDa evidenced the stability of collagen network. The positive 222 nm and 195 nm negative CD absorption band indicated the existence of a triple-helix structure for type I collagen. The preservation of the morphology and functional group of the collagen network on the etched dentin surface were investigated by in vitro dentin decalcification model. Conclusion: Unlike NaOCl, the 5 wt% zinc chloride solution combined with ultra-sonication showed dissolution rather than denature as well as degradation of the dentin collagen network. Additional in vivo evaluations are needed to verify its usefulness in clinical applications.

Progesterone (P4) plays a pivotal role in regulating the cancer progression of various types, including breast cancer, primarily through its interaction with the P4 receptor (PR). In PR-negative breast cancer cells, P4 appears to function in mediating cancer progression, such as cell growth. However, the mechanisms underlying the roles of P4 in PR-negative breast cancer cells remain incompletely understood. This study aimed to investigate the effects of P4 on cell proliferation, gene expression, and signal transduction in PR-negative MDA-MB-231 breast cancer cells. P4-activated genes, associated with proliferation in breast cancer cells, exhibit a stimulating effect on cell growth in PR-negative MDA-MB-231 cells, while demonstrating an inhibitory impact in PR-positive MCF-7 cells. The use of arginine-glycine-aspartate (RGD) peptide successfully blocked P4-induced extracellular signal-regulated kinase 1/2 (ERK1/2) activation, aligning with computational models of P4 binding to integrin αvβ3. Disrupting integrin αvβ3 binding with RGD peptide or anti-integrin αvβ3 antibody altered P4-induced expression of proliferative genes and modified P4-induced cell growth in breast cancer cells. In conclusion, integrin αvβ3 appears to mediate P4-induced ERK1/2 signal pathway to regulate proliferation via alteration of proliferation-related gene expression in PR-negative breast cancer cells.

Abstract: Background/purpose: Overlay restorations can be used clinically as a treatment option to preserve natural dentine. However, whether the residual enamel thickness and overlay thickness affect the adhesion between the restoration and tooth is still unknown. This study was to investigate effects of the overlay thickness and residual enamel thickness on bonding strength. Materials and methods: Overlays of different thicknesses were prepared with natural teeth which had 2, 4, and 6 mm of occlusal reduction (n = 10). Specimens were subjected to 10,000 cycles in water at 5–55 °C, and finally compressive strength tests were used to evaluate the bonding strength. Results: All groups showed good bond strength (P > 0.05). The overlay restorations of different thicknesses reduced the preparation amount by 30.3%–7.2% and significantly preserved more of the tooth structure (P

Background/purpose: Culture environments play a critical role in stem cell expansion. This study aimed to evaluate the effects of 2,3,5,4′-tetrahydroxystilbene-2-O-b-D-glucoside (THSG) on the proliferation and differentiation of human dental pulp stem cells (DPSCs) in 2-dimensional (2D) and 3-dimensional (3D) culture systems. Materials and methods: Human DPSCs were seeded in T25 flasks for 2D cultivation. For the 3D culture system, DPSCs were mixed with microcarriers and cultured in spinner flasks. Cells in both culture systems were treated with THSG, and cell proliferation was determined using a cell counter and a 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl-tetrazolium bromide assay. In THSG-treated DPSCs, the genes associated with proliferation, adipogenesis, neurogenesis, osteogenesis, pluripotency, oncogenesis, and apoptosis were analyzed using real-time polymerase chain reactions. Results: The spinner flask time-dependently improved cell numbers, cell viability, and expansion rates in THSG-treated DPSCs. In both the T25 and spinner flasks, the messenger RNA (mRNA) levels of proliferation, osteogenesis, and pluripotent-related genes had a significant maximum expression with 10 μM THSG treatment. However, 0.1 μM of THSG may be the most suitable condition for triggering neurogenesis and adipogenesis gene expression when DPSCs were cultured in spinner flasks. Furthermore, the number of oncogenes and apoptotic genes decreased considerably in the presence of THSG in both the T25 and spinner flasks. Conclusion: The spinner flask bioreactor combined with THSG may upregulate proliferation and lineage-specific differentiation in DPSCs. Thus, the combination can be used to mass-produce and cultivate human DPSCs for regenerative dentistry.

Abstract Background/Purpose: Although 2,3,5,4′-Tetrahydroxystilbene-2-O-beta-glucoside (THSG) reportedly has anti-inflammatory properties, its role in inducing the dedifferentiation of human dental pulp stem cells (DPSC) into pluripotent-like stem cells remains to be determined. The purpose of this study is to evaluate the effects of THSG on the pluripotent-like possibility and mechanism of DPSC. Materials and methods: DPSCs were treated with THSG, and cell viability was determined using the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl-tetrazolium bromide (MTS) assay. Real-time polymerase chain reaction was used to analyze the mRNA expression levels of pluripotency-associated genes and oncogenes and to detect telomerase activity in the cells. Embryoid body formation assay was conducted, and pluripotency-related proteins were identified using Western blotting. Data were analyzed using one-way analysis of variance. Results: Cell viability, telomerase activity, and embryoid body formation were enhanced in THSG-treated DPSCs. The mRNA expression levels of pluripotent-like genes (including Nanog homeobox [NANOG], SRY-box 2 [SOX2], and POU class 5 homeobox 1 [POU5F1/OCT4]) significantly increased after THSG treatment. The expression levels of pluripotency-related genes (Janus kinase-signal transducer 2 [JAK2] and signal transducer and activator of transcription 3 [STAT3]) increased, whereas those of oncogenes (Ras, SRC, HER2, and C-sis) decreased. Furthermore, the expression levels of the phosphorylated JAK2 and STAT3 proteins significantly increased after THSG treatment. Conclusion: THSG treatment may enhance the pluripotent-like possibility of DPSC through the JAK2/STAT3 axis. Hence, it may be used as an alternative cell-based therapeutic strategy in regenerative dentistry.

Background/purpose: Dental pulp stem cells (DPSCs) contribute to the regeneration of various tissues and have superior proliferation, immune privilege, and anti-inflammation properties to other mesenchymal stem cells. 2,3,5,4′-tetrahydroxystilbene-2-O-β-D-glucoside (THSG) not only enhances the aforementioned properties of DPSCs but also promotes self-renewal and reprogramming-like ability. However, whether THSG enhances the aforementioned properties and abilities through direct or indirect interaction mechanisms remains unclear. To address this knowledge gap, we examined the effects of THSG-stimulated DPSC-derived conditioned medium (THSG-CM) on the activity and anti-inflammation properties of cells. Materials and methods: DPSCs were treated with various concentrations of THSG to produce THSG-CM, which was then collected, analyzed, and lyophilized. A cytokine profiling antibody assay was used to compare protein components between THSG-treated and nontreated CM. Human skin fibroblasts (HSFs) and human gingival fibroblasts (HGFs) were used to investigate the effect of THSG-CM on cell proliferation, anti-inflammation, and wound healing abilities; for this investigation, MTS assay, quantitative real-time PCR analysis, and 2-well silicone inserts wound model were conducted. Results: We observed that THSG enhanced the secretion of growth- and immune-associated proteins in THSG-CM and increased the proliferation of HSFs and HGFs. Furthermore, THSG-CM significantly attenuated lipopolysaccharide-stimulated mRNA levels of cytokines in both cells and improved wound healing abilities. Conclusion: We conclude that THSG-CM had more beneficial effects on cell activity and anti-inflammation in the HSFs and HGFs than DPSC-derived CM. DPSC-derived CM can be developed into a cell-free regenerative strategy in the future, and its therapeutic efficacy may be improved by THSG-CM.

Background/purpose: Dysregulation of cell cycle checkpoint control may lead to the independence of growth regulating signals. Checkpoint protein such as the PD-1/PD-L1 immune checkpoint involving tumor cells and host immune defense lymphocytes is a well-studied therapeutic target in oncology. Acting at a cell surface receptor on plasma membrane integrin αvβ3, thyroxine stimulates intracellular accumulation of PD-L1 in cancer cells. Although resveratrol also binds to integrin αvβ3, it reduces PD-L1 expression. Materials and methods: In current studies, we investigated the roles of resveratrol and thyroxine in regulating expression of proliferation-related genes and checkpoint genes, PD-L1, BTLA in two oral cancer cell lines. Results: Thyroxine suppressed the expression of pro-apoptotic BAD but induced proliferative CCND1 expression in SSC-25 cells and OEC-M1 cells. It activated expression of PD-L1 and BTLA in both cell lines. On the other hand, resveratrol suppressed the expression of all. Alternatively, it activated BAD expression. Thus thyroxine induces checkpoint gene expression which may promote proliferation in cancer cells. Alternatively, resveratrol reverses the stimulatory effects of thyroid hormone to induce anti-proliferation. Conclusion: These findings provide new insights into the antagonizing effect of resveratrol on the thyroxine-induced expression of checkpoint genes and proliferative genes in oral cancers. Keywords: L-thyroxine, Resveratrol, Checkpoint genes, Oral cancer

Background/purpose: To evaluate the measurement accuracy of hard-tissue thicknesses adjacent to dental implants with different thread designs on images obtained from cone beam computed tomography (CBCT) using an in vitro model. Materials and methods: On 4 × 13-mm implant, the neck of the implant was designed with micro-threads, and the apical part was covered by macro-threads; these implants were placed in a vinyl polysiloxane block that mimicked hard-tissue. Models were prepared with various thicknesses of 2.0, 1.0, 0.5 and 0.3 mm adjacent to the dental implant. Each model was scanned using CBCT, and the thickness of the cortical bone from the outer surface of the micro-threads and macro-threads were recorded. Ground sections were prepared, and the thickness was measured with electronic calipers as the gold standard (GS) measurement. Results: CBCT measurements of the micro-thread surface were consistently underestimated compared to the GS measurement when the thickness of the hard-tissue-mimicking material was ≤1.0 mm. In comparison, CBCT measurements of the macro-thread surface closely approximated the standard measurement, except when the thickness of the hard-tissue-mimicking material was 0.3 mm. The mean percentage errors from the standard measurement for the 2.0-, 1.0-, 0.5-, and 0.3-mm thickness groups were 4.8%, 16.4%, 37.8%, and 92.6%, respectively, for the micro-thread group, and were 0.6%, 2.9%, 9.5%, and 40.8%, respectively, for the macro-thread group. Conclusion: Within the limitations of this study, we conclude that CBCT may not produce sufficient resolution for thin sections of hard tissue-mimicking materials adjacent to micro-thread surfaces. Keywords: Cone beam computed tomography, Bone thickness, Dental implant

Background/purpose: The aim of this study was to investigate whether storage of extracted teeth in transportation solution for 24 hours has a negative effect on the cell density and mechanical properties of thawed pulp tissue extracted from frozen intact teeth. Material and methods: Human premolars were kept in transportation solution for 0 hours or 24 hours. For each transportation time, the tested teeth were divided into two experimental groups: teeth that had been frozen in a magnetic programmed freezer (PF, n = 5) and in a traditional freezer at −20°C (TF, n = 5). The tested teeth were then stored at −150°C for 7 days. After thawing, the extracted pulp was subjected to a histological examination and mechanical testing. Results: Storage in transportation solution for 24 hours had no significant negative effects on the histological or mechanical properties of the pulp tissue extracted from the cryopreserved intact teeth. The elastic modulus of pulp from the teeth that had been frozen at −20°C was significantly higher (P

Background/purpose: Distal radius fractures are amongst the most common musculoskeletal bone injuries treated in emergency departments. The objective of this study was to evaluate the functional and radiologic outcomes of treating distal radius fractures with a resorbable volar polymeric implant system. Materials and methods: We applied the volar poly-5D/95L-lactide (PLA95) plate/screw system (Bonamates, BioTech One, New Taipei City, Taiwan) for intraosseous fixation after open reduction of distally displaced radius fracture in four patients (three males and one female, ages range: 7–67 years). Another four patients [three females and one male, ages 68–70 (68.8 ± 1.0)] were treated with 3.5-mm metal volar T locking plates (Synthes, Paoli, PA, USA) as the control group. The minimum follow-up period was longer than 2.5 months for all cases. Results: At final functional and radiologic assessment, all of the distal radius fracture sites were united and one patient achieved excellent results, two patients had good results, and one had a fair result. All patient outcomes were satisfactory, and no major material-related infections or allergies were found. Conclusion: Within the limitations of this early clinical experiment, we conclude that the volar PLA95 copolymer plate/screw system can be used to treat distal radial fractures.

Background/purpose: The aim of this study was to examine the effects of the time period between tooth extraction and the freezing procedure on pulp cells in frozen intact teeth of rats. Material and methods: In total, 120 incisors from 30 rats were extracted and kept in transportation solution for 0 hour, 12 hours, and 24 hours. The tested teeth were divided into 2 experimental groups, where the extracted incisors were first frozen in a magnetic-programmed freezer (PF) or a traditional −20°C freezer (TF). The tested teeth were then stored at −150°C for 7 days. Incisors extracted from the opposite side of the same rat were treated as the non-frozen control. After thawing, the pulp was extracted and dissected. Hematoxylin and eosin staining was performed to observe the cell distributions. Cell densities in the odontoblast region and cell-rich zone were calculated using an optical microscope. Results: When samples were immediately frozen after extraction, the cell density of odontoblastic cells was higher in the PF group compared with analogs which were frozen in the −20°C freezer (P

Unlike other deep cancers, oral squamous cell carcinoma (OSCC), which occurs in the oral cavity, is more easily monitored, and specimens for diagnosis are easier to collect. However, identifying reliable and sensitive markers for the early diagnosis and markers for identification of the recurrence of OSCC remains a challenge. This article mainly focused on reviewing recently identified potential biomarkers for a cytologic diagnosis during OSCC development. In addition, markers used in modern diagnostic technologies, including a sensitive labeling method and a photodynamic approach for cytologic diagnosis, are also described. Cytologic examinations using sensitive and specific biomarkers can improve the accuracy of the diagnosis. Hence, they can lead to appropriate treatment without delay and to the reduced recurrence of OSCC.

Poorly crystalline hydroxyapatite was improved so that it has better cell affinity in vitro. We studied the efficacy of a novel resorbable poorly crystalline hydroxyapatite-based biphasic calcium phosphate, BonaGraft, for bone regeneration in vivo. Materials and methods: The beagle was used as an animal model, and cylindrical artificial bone defects (3 mm in diameter and 6 mm long) were produced in the alveolar bone. The BonaGraft (ratio of poorly crystalline hydroxyapatite to b-tricalcium phosphate, 60:40) was used to fill in the defect, and unfilled defects served as a control group. At 5, 8 and 10 weeks after the operation, the size of the residual graft and new bone formation were evaluation by a histomorphometric analysis. In a clinical trial, 33 enrolled patients included 15 males and 18 females with ages ranging from 35 to 54 years. The main indications were ridge augmentation (n = 12), sinus lifting (n = 2), repair of periodontal disease (n= 14), and repair of radicular cysts (n= 5). The clinical outcomes of the surgery were primarily evaluated by clinical radiographs. Results: In the animal study, implanting BonaGraft produced greater new-bone formation (74.5% ± 1.0%) at 10 weeks postoperatively than that of the control (40.2% ± 0.3%). BonaGraft particles were gradually resorbed and substituted by bone. The in vivo graft resorption time and bone healing time of 12.1 weeks were mathematically determined by the least squares method. In the clinical test, all patients implanted with BonaGraft reported satisfactory clinical outcomes without major material-related side effects. According to the radiographic pictures, implantation of BonaGraft enhanced bone formation. Conclusion: According to the animal study results, BonaGraft has a suitable resorption period and satisfactory outcomes of new bone formation. The clinical study produced high satisfaction with clinical results both objectively and subjectively. For this reason, BonaGraft seems to be an alternative choice for a bone substitute in dental applications.

The bionator is one of the most commonly used functional appliances in treating Angle Class II division 1 malocclusions. However, the original type of bionator often causes lower incisor flaring and is limited in cases with mild crowding. There is little published literature on treating Angle Class II division 2 malocclusions using bionators. Our group suggested some modifications to the original-type bionator, including addition of an anterior resin cap, upper and lower labial bows, an expansion screw and a posterior resin wedge, to attempt to overcome limitations of the original design. This article shows our results on two male patients, one with an Angle Class II division 1 malocclusion with a large overjet and the other with an Angle Class II division 2 malocclusion. The treatment was completed using a newly modified bionator with no other fixed appliance and resulted in a decrease in facial convexity, a reduced overjet and overbite, ideal interincisal relationships, and a harmonious profile.

Assessing periodontal conditions has always been a concern for dental researchers. In this study, we evaluated the potential of a natural frequency (NF) analysis to detect the health status of natural human canine teeth. Materials and methods: Three-dimensional finite element models of the human maxillary canine were constructed. NF values of the canine model were calculated with one-, two- and three-sided vertical bone loss. Results: By simulating a modal testing experiment, the NF value for a healthy canine was found to be 2581 Hz. As the bone level was lowered, a strong linear relationship between the frequency and attachment level was demonstrated in all three models. Results from this study demonstrated that the change in the NF was < 12% in canines with a one-sided defect when the bone level varied by 10 mm from the cementoenamel junction. However, when a three-sided bony defect was simulated, the change in NF ranged from 20% to 60%. Conclusion: This study demonstrates that the NF of the human canine decreases with various degrees of periodontal bone height loss.