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A tricalcium-silicate-nanoparticle-containing cement (Biodentine) was developed to overcome the disadvantages of existing mineral trioxide aggregate (MTA) dental materials. This study aimed at evaluating the effects of Biodentine on the osteogenic differentiation of human periodontal ligament fibroblasts (HPLFs) in vitro and the healing of furcal perforations created experimentally in rat molars in vivo, in comparison to MTA. The in vitro studies performed the following assays: pH measurement using a pH meter, the release of calcium ions using a calcium assay kit, cell attachment and morphology using SEM, cell proliferation using a coulter counter, marker expression using quantitative reverse transcription polymerase chain reaction (qRT-PCR) and cell mineralized deposit formation using Alizarin Red S (ARS) staining. In the in vivo studies, MTA and Biodentine were used to fill the rat molar perforations. Rat molars were processed at 7, 14 and 28 days for analysis of inflammatory processes using hematoxylin and eosin (HE) staining, immunohistochemical staining of Runx2 and tartrate-resistant acid phosphate (TRAP) staining. The results demonstrate that the nanoparticle size distribution of Biodentine is critical for osteogenic potential at an earlier stage compared to MTA. Further studies are required to elucidate the mechanism of action of Biodentine in osteogenic differentiation. [ABSTRACT FROM AUTHOR]

Odontoblasts are involved in sensory generation as sensory receptor cells and in dentin formation. We previously reported that an increase in intracellular cAMP levels by cannabinoid 1 receptor activation induces Ca2+ influx via transient receptor potential vanilloid subfamily member 1 channels in odontoblasts, indicating that intracellular cAMP/Ca2+ signal coupling is involved in dentinal pain generation and reactionary dentin formation. Here, intracellular cAMP dynamics in cultured human odontoblasts were investigated to understand the detailed expression patterns of the intracellular cAMP signaling pathway activated by the Gs protein-coupled receptor and to clarify its role in cellular functions. The presence of plasma membrane Gαs as well as prostaglandin I2 (IP), 5-hydroxytryptamine 5-HT4 (5-HT4), dopamine D1 (D1), adenosine A2A (A2A), and vasoactive intestinal polypeptide (VIP) receptor immunoreactivity was observed in human odontoblasts. In the presence of extracellular Ca2+, the application of agonists for the IP (beraprost), 5-HT4 (BIMU8), D1 (SKF83959), A2A (PSB0777), and VIP (VIP) receptors increased intracellular cAMP levels. This increase in cAMP levels was inhibited by the application of the adenylyl cyclase (AC) inhibitor SQ22536 and each receptor antagonist, dose-dependently. These results suggested that odontoblasts express Gs protein-coupled IP, 5-HT4, D1, A2A, and VIP receptors. In addition, activation of these receptors increased intracellular cAMP levels by activating AC in odontoblasts. [ABSTRACT FROM AUTHOR]

Author(s): Tatsuya Shimoda [1, 4]; Yasuo Matsuki [2, 4]; Masahiro Furusawa (corresponding author) [1, 4]; Takashi Aoki [1]; Ichio Yudasaka [1]; Hideki Tanaka [1]; Haruo Iwasawa [2]; Daohai Wang [2]; [...]

CD90 expression and immunoreactive cell localisation in rat dental pulp cells after cavity preparation was investigated. Cavity preparation was performed on the maxillary first molar of 8‐week‐old Wistar rats (n = 36), and immunohistochemistry and quantitative real‐time PCR were performed. CD90‐immunoreactivity was observed among subodontoblastic cells in the control group. One day after cavity preparation, the CD90‐immunoreactivity disappeared under the cavity area. While CD90‐immunoreactivity was faint after 3 days, the re‐arrangement of odontoblasts was detected in contact with dentine. After 5 days, the odontoblasts were observed beneath the dentine, and CD90‐immunoreactive cells were localised under the odontoblast layer. Immunofluorescence showed co‐localisation of CD90 and nestin was detected after 3 days. After 5 days, CD90‐immunoreactivity increased at the subodontoblastic layer. mRNA expression of CD90 and DSPP decreased after cavity preparation, and gradually recovered (P < 0.01). These results suggest that CD90‐immunoreactive cells in the subodontoblastic layer contribute to regeneration of odontoblast and subodontoblastic layers following cavity preparation. [ABSTRACT FROM AUTHOR]

This study evaluated the microtensile bond strength (μTBS) of 1-step self-etch adhesives (1-SEAs) and 2-step self-etch adhesives (2-SEAs) to pulp chamber dentin immediately after bleaching with 2 types of common bleaching techniques. Pulp chamber dentin of bovine teeth was bleached using 30% hydrogen peroxide (H2O2) solution with quartz-tungsten-halogen light-curing unit (Group 1) and 3.5% H2O2-containing titanium dioxide (TiO2) (Pyrenees®) activated with 405-nm violet diode laser for 15 min (Group 2). Unbleached specimens were placed in distilled water for 15 min and used as controls. After treatment, dentin was bonded with resin composite using 1-SEA or 2-SEA and stored in water at 37°C for 24 h. Each specimen was sectioned and trimmed to an hourglass-shape and μTBS was measured. Fractured specimens were examined under a scanning electron microscope to determine fracture modes. All specimens in Group 1 failed before proper bonding tests. In Group 2, the μTBS of 2-SEA was significantly greater (with no failed specimens) than 1-SEA (where 21 out of 36 failed). These results indicate that 2-SEA is a better adhesive system than 1-SEA on bleached dentin. Our results also demonstrated that application of H2O2 significantly decreases bond strength of resin to dentin; however, in the case of nonvital tooth bleaching, Pyrenees® is a better alternative to the conventional 30% H2O2 bleaching. [ABSTRACT FROM AUTHOR]

ABSTRACT Gap junctions play an important role in differentiation of odontoblasts. Gap junction protein, connexin 43 is expressed in odontoblast. However, the detailed localization in odontoblasts has yet to be fully investigated. We investigated the localization of connexin43 in rat odontoblasts immuno-electron microscopically. The rats were transcardially fixed with 1% paraformaldehyde in 0.1M phosphate buffer, and mandibles were decalcified with 10% ethylenediamine tetraacetic acid. Pre-embedding method was carried out for immuno-electron microscopic analysis. Microscopically, gap junctions were localized between bodies of odontoblasts, and between bodies and processes of odontoblasts. The gap junctions were labeled with gold particles that indicated connexin43. These results suggest that gap junctions between odontoblasts are definitely composed of connexin43 in rats, and our methods used in this study is useful to investigate localization of connexin43 immuno-electron microscopically. Microsc. Res. Tech., 76:988-991, 2013. © 2013 Wiley Periodicals, Inc. [ABSTRACT FROM AUTHOR]

The aim of this study was to investigate whether atmospheric-pressure plasma (APP) or ultraviolet (UV) irradiation could alter the hydrophilicity of a computer-aided design/computer-aided manufacturing (CAD/CAM) glass ceramic surface, and thereby enhance the repair bond strength between the ceramic and a resin composite. Forty-eight leucite-reinforced glass ceramic discs were treated with 40% phosphoric acid and randomly assigned into one of six groups: Group 1, control; Group 2, treated with a mixture of Clearfil SE Bond primer (SEP) and Clearfil Porcelain Bond Activator (PBA); Group 3, subjected to APP irradiation for 10 s; Group 4, subjected to UV irradiation for 60 min; Group 5, APP irradiation followed by SEP/PBA; and Group 6, UV irradiation followed by SEP/PBA. After treatment, discs were bonded with resin composite using Clearfil SE Bond and stored in water at 37 °C for 1 week. We then tested how these treatments affected the microtensile bond strength (µTBS) and measured changes in the water contact angle (CA). Samples from Group 2 showed the highest µTBS (44.3 ± 6.0 MPa) and CA (33.8 ± 2.3°), with no significant differences measured between Groups 1, 3, and 4 (p < 0.05). Furthermore, the additional treatments of APP or UV before SEP/PBA had no effect (Group 5, p = 0.229) or a reduced effect (Group 6, p = 0.006), respectively, on µTBS. Overall, APP or UV irradiation before SEP/PBA treatment did not enhance the repair bond strength. [ABSTRACT FROM AUTHOR]

Abstract: Objectives: This study is aimed to test whether glucose-free conditions induce the activation of adenosine monophosphate-activated protein kinase (AMPK) and, to investigate association with AMPK expression and cell viability in human dental pulp cells. Design: Human dental pulp cells were initially maintained in culture medium containing glucose and the medium was subsequently changed to glucose-free medium. To evaluate the expression of AMPK, quantitative real-time RT-PCR, Western blot analysis and immunofluorescence were carried out. Cell viability was evaluated by MTT assay. Results: The expression of AMPK mRNA in glucose free conditions was 2.0–2.5 fold higher than the control at 1, 2 and 3h (P <0.01). The expression of phosphorylated-AMPK was characterized by Western blot analysis and by immunofluorescence. Compound C-pre-treated group showed a decline of both AMPK expression and cell viability, while AICAR-pre-treated group showed an increase of AMPK and maintain of cell viability at regular level. Conclusions: AMPK plays an important role on fluctuating in accordance with glucose availability and protects cell viability from glucose free condition in human dental pulp cells. [Copyright &y& Elsevier]

Abstract: Calcitonin gene-related peptides (CGRP) and adrenomedullin (ADM) belong to the calcitonin family of peptides and are structurally related. Both peptides are found in the neurons of the CNS and play a role in many neuronal functions, including the control of blood pressure. The nucleus tractus solitarius (NTS) is known to play a major role in the regulation of cardiovascular, respiratory, gustatory, hepatic and swallowing functions. Recently, hypotension and bradycardia were observed after CGRP and ADM injection in the NTS. Voltage-dependent Ca2+ channels (VDCCs) serve as crucial mediators of membrane excitability and Ca2+-dependent functions, such as neurotransmitter release, enzyme activity, and gene expression. The purpose of this study is to investigate the effects of CGRP and ADM on VDCC currents (I Ca) carried by Ba2+ (I Ba) in the NTS, using patch-clamp recording methods. Application of CGRP and ADM caused facilitation of I Ba in a concentration-dependent manner. Intracellular dialysis of the anti-Gαs-protein antibody attenuated CGRP-induced facilitation of I Ba. Intracellular dialysis of the anti-Gαi-protein antibody attenuated ADM-induced facilitation of I Ba. Pretreatment with SQ22536 (an adenylate cyclase inhibitor) and intracellular dialysis of PKI(5–24) (a protein kinase A inhibitor) attenuated CGRP-induced facilitation of I Ba. In contrast, pretreatment with PD98,059 (a mitogen-activated protein kinas inhibitor) attenuated ADM-induced facilitation of I Ba. Mainly L-type VDCCs were facilitated by both CGRP and ADM. These results indicate that CGRP facilitates L-type VDCCs via Gαs-protein involving adenylate cyclase and protein kinase A. In contrast, ADM facilitates L-type VDCCs via Gαi-protein involving mitogen-activated protein kinase in the NTS. [Copyright &y& Elsevier]

Aim: To compare the bond strength of two resin cements to leucite-reinforced ceramics using three different boding agents and evaluate the compatibility of bonding agents., Materials and Methods: Twenty extracted sound human molars were sectioned horizontally 2-3 mm above the cementoenamel junction (CEJ). CAD/CAM ceramic blocks for inLab were also sectioned to create 4 mm thick and bonded to the dentin. The adhesive groups assigned were divided into four adhesive groups: Group I: Variolink II dual-cure resin cement and Scotchbond Multi-Purpose Plus adhesive, group II: Multilink Automix dual-cure resin cement and Multilink primers, group III: Multilink Automix and Clearfil SE bond 2 (CSE2) adhesive, group IV: Multilink Automix and CSE2 with light curing after adhesive application. Five specimens of each group were sectioned perpendicular to obtain six microsticks of 1 × 1 mm width from each sample. Microtensile bond strength data were expressed in MPa. Fracture modes (FrMs) analyzed for the surfaces were divided into six patterns. Microtensile bond strength data were statistically analyzed with one-way ANOVA and Tukey post hoc tests (α = 0.05). T -test was performed at the 5% significance level to analyze groups III and IV with and without light curing., Results: Group I showed the highest μTBS average of 13.67 MPa, group IV showed 12.26 MPa, group III showed 12.15 MPa, and group II showed the lowest average of 10.84 MPa. No significant differences were found between the bonding agents. However, the six types of failure modes, although all observed, were characterized by the adhesive system: Type I: adhesive failure of laminated dentin and ceramic; type II: adhesive failure of laminated ceramic; type III: adhesive failure of laminated dentin; type IV: cohesive failure of luting agent; type V: cohesive failure of dentin, and type VI: mixed failure of adhesion and cohesion. As a result, the FrM most commonly observed was the adhesive failure at the luting cement-ceramic block interface., Conclusion: The combination of resin cements and bonding agents did not significantly affect the bond strength of CAD/CAM ceramic restorations and dentin., Clinical Significance: Several universal bonding agents are currently available for direct and indirect bonding, and using the same bonding agent for direct and indirect restorations could simplify inventory and benefit routine clinical practice. How to cite this article: Aida N, Koi K, Amaya-Pajares SP, et al . Bond Strength of Two Resin Cements with Leucite-reinforced Ceramic Using Different Bonding Agents. J Contemp Dent Pract 2023;24(11):859-863.

Dens invaginatus is a morphological abnormality of the tooth that results from a developmental anomaly during tooth formation, in which part of the enamel and dentin of the crown invaginates into the pulp cavity. This report describes a case of a maxillary lateral incisor with apical periodontitis apparently caused by Oehlers Type III dens invaginatus. The patient was a 69-year-old man who visited our clinic complaining of discomfort in the maxillary right lateral incisor. Cone-beam computed tomography (CBCT) revealed dens invaginatus of the maxillary lateral incisor and a sinus tract in the maxillary central incisor region, which was derived from apical periodontitis of the maxillary lateral incisor. The dens invaginatus was accompanied by a complex root canal morphology. Treatment, which was performed using a dental surgical microscope, had a favorable outcome. The patient remains in good condition at 1 year postoperatively.

The recent use of cone beam computed tomography (CBCT) in the field of dentistry to obtain 3-dimensional (3D) images has enabled more effective examination and diagnosis in endodontic treatment. Such information has also been reported to be of benefit in surgical endodontic treatment such as intentional replantation. Here, we report a case of intentional replantation with the assistance of CBCT in which a good therapeutic outcome was achieved. The patient was a 30-year-old woman who visited our hospital with the chief complaint of spontaneous pain in the right maxillary first molar. Dental radiographs revealed a radiolucent area in the apical portion of the distal root, and a radiopaque area thought to be a broken shard from a small surgical instrument measuring approximately 1.5 mm in length. The shard was located outside the distal apical foramen. Based on these findings, the diagnosis was acute suppurative apical periodontitis of the right maxillary first molar. Infected root canal therapy was subsequently commenced. The patient's symptoms showed no improvement, however, and the pain persisted. Therefore, dental CBCT was performed to obtain 3D images, which confirmed a radiopaque area thought to be a broken shard from a small surgical instrument located outside the apical foramen of the distal root and facing in a direction that made it impossible to remove from the root canal. Because the patient's symptoms had shown no improvement and a foreign body was observed outside the apical foramen, intentional replantation combined with root resection was performed with informed consent. At a 1-year follow-up visit, progress was good, and there were no reported symptoms or signs. When reaching a diagnosis is difficult based on clinical findings and dental radiographs alone, the 3D images provided by CBCT offer a means of securing a more reliable diagnosis, allowing planning of treatment to be more effective.

Hypobromous acid (HOBr) is generated not only by eosinophils but also by neutrophils in the presence of Br - at the plasma concentration. Reactivity of HOBr is greatly modulated by coexistent compounds such as amines and amides. In this study, we investigated effects of urea in the reaction of nucleosides with HOBr. When nucleosides were incubated with HOBr without urea in potassium phosphate buffer at pH 7.4 and 37°C, the reactions almost completed within 10 min, with consumptions in the order of 2'-deoxyguanosine > 2'-deoxycytidine > 2'-deoxythymidine > 2'-deoxyadenosine, generating 8-bromo-2'-deoxyguanosine and 5-bromo-2'-deoxycytidine. In the presence of urea, the reaction of nucleosides with HOBr was relatively slow, continuing over several hours. When HOBr was preincubated without urea in potassium phosphate buffer at pH 7.4 and 37°C for 48 h, the preincubated HOBr solution did not react with nucleosides. However, a similar preincubated solution of HOBr with urea reacted with nucleosides to generate 8-bromo-2'-deoxyguanosine and 5-bromo-2'-deoxycytidine. These results imply that a reactive bromine compound with a long life, probably bromourea, is generated by HOBr in neutral urea solution and reacts with nucleosides, resulting in brominated nucleosides.

Apical periodontitis is usually diagnosed based on clinical findings and dental X-rays. Recently, however, dental cone beam computed tomography (CBCT), which provides 3-D images of the maxillofacial region, has enabled dentists to examine patients undergoing endodontic therapy more effectively, improving diagnostic accuracy. Here, we describe a positive treatment outcome achieved using CBCT to diagnose apical periodontitis of the maxillary premolars, which had proven difficult to diagnose based on clinical findings and dental radiography alone. The patient was a 42-year-old Japanese man who presented with the chief complaint of gingival swelling in the maxillary right premolar region. Our initial diagnosis, based on clinical findings and dental X-ray, was apical periodontitis of the maxillary right second premolar, and treatment was started. However, after the patient failed to respond to the treatment, CBCT was performed. Based on these new findings, the diagnosis was changed to one of apical periodontitis of the upper right first premolar, and the patient was treated accordingly. Previous studies have described the complex anatomical morphology of the upper premolars, noting multiple roots and variation in the morphology of the root canals. The 3-D images provided by dental CBCT allow better assessment of oral conditions than the traditional 2-D images provided by dental X-rays, which in turn enables the dentist to better select the most appropriate treatment. Here, the patient showed no symptoms and was progressing well at a 6-month follow-up visit. The present results indicate that when clinical findings and dental X-rays alone are insufficient to allow a secure diagnosis, CBCT offers an effective alternative which will enable the appropriate treatment to be selected more reliably.

The objective of this study is to investigate the responses of human cementoblasts to light compressive force in vitro. A human cementoblast cell line (HCEM) was loaded for 12 h by mounting coverslips (0.25 gf/cm 2 ). The coverslips were removed and the cells were cultured for up to 21 days. Cells without glass loading were used as controls. Cell growth, morphological changes, and the mRNA expression of RUNX2, ALP, WNT5A and SPON1 were investigated. No significant differences were observed in cell numbers between the compressed group and control group. Morphology of the compressed cells was slightly flattened on day 0; however, no indications of cell death were detected. Expression of differentiation markers including RUNX2, ALP and WNT5A was significantly lower in the compressed group (0.7, 0.75 and 0.75-fold respectively, P < 0.05) than in the control group on day 7. The expression levels of SPON1, a differentiation marker of cementoblasts, were higher on days 7 and 14 than on day 0, but were lower in the compressed group than in the control group (P < 0.01). These results suggest that light compressive force does not affect cell growth and morphology, but restrains higher expression of cementogenic differentiation markers in human cementoblasts in vitro.

As of fiscal year 2006, it became compulsory for all newly licensed dentists in Japan to undergo a year of practical training at one of the designated training facilities found throughout the country as part of their postgraduate programs. The goal of this training is for the trainees to acquire diagnostic and therapeutic skills. While officially trainees, they are nonetheless regarded as members of staff. Clinical training emphasizes improving both technical skills and theoretical knowledge. However, taking on such trainees is sometimes considered unprofitable, as work productivity is claimed to be low. The purpose of this study was to compare work outcomes and income generated between trainees and part-time dentists working at the Tokyo Dental College Suidobashi Hospital. The part-time dentists comprised clinical instructors and dentists responsible for outpatients. Postgraduate dental trainees also generally conduct dental treatment for outpatients. Therefore, part-time dentists were considered the most suitable for a control group. No significant difference was observed in the total number of patients seen by either group by the final term of clinical training. Furthermore, no significant difference was observed in insurance-based dental treatment unit income (insured care unit income) per patient between the two groups from the mid-term period of training onwards. These results suggest that, although the trainees were less efficient in terms of time taken to provide a diagnosis and treatment, their performance was almost equal when viewed from the viewpoint of insured care provided. Taken together, this suggests that time-related care efficiency must be increased and specific training policies and strategies developed to improve the work productivity of dental trainees.

Calcium deposited within a root canal due to exogenous stimuli may hamper root canal treatment. In endodontic treatment, an operating microscope allows the conditions within the root canal to be directly viewed and evaluated. This report describes a case in which an operating microscope was used to facilitate the excision of a calcified structure from within a root canal at an early stage in the treatment of an infection. An 18-year-old man was referred to our clinic due to suspected chronic suppurative apical periodontitis of the right maxillary central incisor. Periapical radiography confirmed the presence of a radioopaque structure inside the root canal that was likely to pose an obstacle to endodontic treatment. After opening the pulp chamber, an operating microscope was used to directly confirm the presence of the calcified structure in the root canal, which was removed using an ultrasonic tip. The infected root canal was treated using calcium hydroxide. Two months later, closure of the apical foramen as a result of calcification of the apical foramen was confirmed and the root canal filled. Using an operating microscope to directly view a structure posing an obstacle to root canal treatment made it possible to perform an excision while avoiding risks such as canal perforation.

The purpose of this study was to investigate the influence of superhydrophilic treatments of titanium on the behavior of osteoblastlike cells. Superhydrophilic specimens were prepared with sandblast and acid-etching (DW), oxygen plasma (Plasma) and ultraviolet light (UV), and were stored in distilled water for 3 days immediately after these treatments. Specimens stored in air for 3 weeks were used as a control Air group. Initial cell attachment, proliferation, alkaline phosphatase activity, and osteocalcin secretion of mouse osteoblast-like cells MC3T3-E1 were enhanced more on superhydrophilic groups than were Air specimens. On confocal laser scanning microscope images of cell morphology, the expression of actin filaments was observed on the superhydrophilic groups, whereas relatively little actin filament expression was seen on the Air surfaces on all culture periods. These results indicate that DW, Plasma, or UV treatment has potential for the creation and maintenance of superhydrophilic surfaces and the enhancement of the initial attachment, proliferation, and differentiation of osteoblast-like cells.

The microflora in the periodontal pockets can affect the dental pulp and cause endodontic-periodontal lesions or retrograde pulpitis. Here we report an endodontic-periodontal lesion together with its bacterial profile. The lesion occurred in the maxillary right first molar of a 40-year-old woman who presented at our hospital complaining of a violent toothache since the previous night. Clinically, the tooth was caries-free and an electric pulp test showed it to be vital. The tooth showed signs of advanced periodontitis and the periodontal pocket was deep, reaching the apex of the palatal root. The clinical diagnosis was an endodontic-periodontal lesion with primary periodontal disease. Subsequent endodontic treatment comprised pulp extirpation and root canal filling, followed by periodontal treatment consisting of scaling and root planing. The tooth was finally restored with a full metal crown. No further signs of periodontal disease or periapical lesions have been observed to date. Bacteria were sampled from the root canal and periodontal pocket for a microbiological assessment using 16S rRNA gene-based PCR. Microbiologically, the profile of the bacterial species from the palatal root canal was similar to that from the periodontal pocket of the palatal root. Porphyromonas gingivalis, Fusobacterium nucleatum and Eikenella corrodens were detected in both samples. The occurrence of bacteria common to both sites in this patient further supports the proposition that periodontal disease is the definitive source of root canal infections. The present results suggest that a bacterial examination would be helpful in confirming and supporting the clinical diagnosis in such lesions.

Career paths and aspirations were investigated among postgraduate dental trainees on completion of clinical training at Tokyo Dental College between 2006, when clinical residency became mandatory, and 2011. Overall, those finding employment with independent general dental practitioners accounted for the majority (34%), followed by those entering postgraduate courses at the Chiba Hospital (20%), those embarking on a postgraduate clinical specialty course at the Chiba Hospital (16%), and those going on to other universities (7%). At the Chiba Hospital, the number selecting postgraduate courses, residency training (including further residency training or a postgraduate clinical specialty course), or employment with a general dental practitioner was almost the same; however, the number selecting postgraduate courses at the Suidobashi Hospital was low, showing a strong tendency toward becoming a general or clinical practitioner. At the Ichikawa General Hospital, most of the trainees decided to remain at the same school or hospital as postgraduate students or residents, showing an aspiration toward further specialization. The results of the Fisher's exact test showed a significant difference in career paths between the Chiba, Suidobashi, and Ichikawa General Hospitals. Trends among postgraduate dental trainees from this and other schools completing the clinical residency program here and subsequently entering postgraduate courses, further residency training, or a postgraduate clinical specialty course at this school were investigated. No major difference was observed in the percentage of trainees remaining at the same school or entering postgraduate courses between those from this and those from other schools; however, more trainees from other schools selected further residency training, while fewer selected a postgraduate clinical specialty course.

The success of root canal therapy is dependent not only on removal of infected pulp (pulpectomy) followed by root canal enlargement, but also on the pharmacological effects of intracanal medications. Various intracanal medications are used. Formaldehyde preparations such as formocresol were common in the past, but these are no longer used in Europe or the US due to the biological toxicity of formaldehyde. In this study, a questionnaire was used to determine current trends in the use of intracanal medications at dental care facilities where dental hygiene students undergo practical training. The questionnaire comprised questions regarding the types of frequently used intracanal medications and their methods of application at dental care facilities in Saitama and Shizuoka prefectures. The results indicated that calcium hydroxide preparations were more commonly used in Europe or the US. However, these results also revealed that formaldehyde preparations were frequently used, which slightly differs from the scenario in Europe and the US. This study revealed that multiple intracanal medications were used for root canal therapy. Furthermore, it was also observed that cotton plugs were generally used as applicator tips for intracanal medications, whereas the use of absorbent paper points was relatively uncommon. The results suggest that the cost of absorbent paper points needs to be reduced.

Trends among dental residents at Tokyo Dental College between 2006, at which time clinical residency became mandatory, and 2011 were analyzed and the following results obtained. Almost all the eligible students from our school participated in the orientation seminar on dental residency programs. Although the number varied slightly by year, approximately 70 to 150 students from other schools also participated in these orientation seminars. Almost all the students from our school and 60 to 80% of those from other schools participating in the orientation seminar each year applied to sit the dental residency entrance examination. The number of candidates was highest in 2006 (318) and lowest in 2010 (205) (average: 248), and the applicant-to-seat ratio for residency was 1.59. The examination pass rate was 59.02%. Approximately 10% of the students from other schools were admitted as dental residents.

We report a case of apical fenestration misdiagnosed as persistent apical periodontitis. The patient was a 55-year-old woman who presented with persistent tooth pain at the right maxillary canine, despite repeated root canal treatment by a general practitioner. When the patient visited Tokyo Dental College Suidobashi Hospital, a CT examination was performed and apical fenestration diagnosed. The patient received an apicoectomy after which the symptoms disappeared. This suggests that dentists should consider the possibility of apical fenestration when examining patients with persistent tooth pain after repeated root canal treatment.

This study aimed to investigate retrospectively the outcome of surgical periodontal therapy. Periodontal surgeries implemented at General Dentistry, Tokyo Dental College Suidobashi Hospital during the period of April 2010 through March 2012 were subjected to data analysis. After initial periodontal therapy, 17 clinicians performed a total of 138 periodontal surgeries in 80 patients with moderate to advanced periodontitis (31 men and 49 women; mean age 54). Cases (sites) operated were as follows: open flap debridement=102, periodontal regenerative therapy=29 (17 for intrabony defects, 12 for furcation involvements) and periodontal plastic surgery=7. Enamel matrix derivative or bone graft was used for regenerative therapy. Clinical data were analyzed focusing on the comparison between open flap debridement and regenerative therapy. At 5 months after open flap debridement, mean reduction in probing depth (PD) and gain in clinical attachment level (CAL) was 3.9 mm (range -1.0-9.0) and 2.3 mm (range -1.0-9.0), respectively. The corresponding values with regenerative therapy were 4.0 mm (range 0-8.0) and 2.8 mm (-1.0-6.0), respectively. At sites with initial PD≥8 mm, a significantly greater gain in CAL was obtained with the regenerative therapy than with flap surgery (mean CAL gain 4.3 mm vs. 2.9 mm, p<0.05). Periodontal surgery performed in our clinical setting demonstrated a favorable short-term outcome. Our data suggest the efficacy of regenerative therapy, in particular for the treatment of deep pockets.

This study aimed to evaluate the effectiveness of Calvital(®), which is a calcium hydroxide formulation, on persistent apical periodontitis caused by over-enlargement of the apical foramen. The study included patients referred to the Department of General Dentistry at Tokyo Dental College Suidobashi Hospital on a diagnosis of persistent apical periodontitis at an external dental clinic. Of them, 20 showing considerable enlargement of the apical foramina were included in the study. Complete disappearance of symptoms was observed in all patients after intracanal application of Calvital(®). We believe that this was due to effective wound-healing brought about the strong alkaline nature of this formulation. We regard Calvital(®) as a highly effective agent for root canal treatment of teeth with persistent apical periodontitis.

The aim of the present study was to investigate the profile of surgical periodontal therapy performed at the Suidobashi Hospital of Tokyo Dental College, during the period of April 2010 through March 2011. A total of 112 periodontal surgeries in 69 patients (mean age: 51.4 years; 28 men and 41 women) were registered for the data analysis. The surgical interventions performed by 17 dentists comprised 79 cases of open flap debridement, 27 cases of periodontal regenerative therapy with enamel matrix derivative and 6 cases of periodontal plastic surgery. Eighty percent of the surgical sites were in the molar region and 41 cases had furcation involvement. In these patients, an improvement in oral hygiene status was observed prior to surgery: the mean plaque score of 45% at initial visit was significantly reduced to 31% after initial periodontal therapy (p<0.01). At sites that subsequently received open flap debridement or periodontal regenerative therapy, the mean probing depth and clinical attachment level after initial therapy was 6.4 mm and 7.6 mm, respectively. These values were significantly lower than those at initial visit (p<0.01). Lower prevalence of sites with positive bleeding on probing was observed after initial therapy. The initial periodontal therapy performed was considered to be effective in improving the periodontal condition of the sites prior to surgery. More effort, however, is indicated in improvement of patient oral hygiene status.

The purpose of this study was to compare the effectiveness of dental checkups incorporating tooth-brushing instruction (TBI) with that of conventional dental checkups. A team consisting of one dentist and three dental hygienists saw an average of 60 employees per day on-site at an airline company. The patient's teeth were stained with a disclosing tablet and the results recorded on a Plaque Control Record (PCR) chart. The patient was then given TBI. After recording the relevant data, including TBI given and PCR scores, the charts were stored. Checkups were performed in a total of 3,854 patients between 2001 and 2005 and changes in annual scores investigated. In addition, annual shifts in mean score in patients receiving checkups over all five years were compared with those in patients receiving checkups for the first time in each of the five years. The mean score in patients receiving a checkup in 2001 was 35.1%, declining by 2.6 points to 32.5% in 2005. Among patients receiving checkups over all five years, the mean score in 2001 was 34.0%, declining by 11.2 points to 22.8% in 2005. Over the five-year period, the mean score in patients receiving checkups was 34.1%. In patients receiving checkups over all five years, the proportion with PCR scores <30% increased each year. This was because the number of patients with PCR scores ≥60% decreased each year. These findings suggest that TBI is effective in reducing poor plaque control. When compared with in patients who had not received TBI, five consecutive years of checkups was clearly effective. These results indicate that checkups incorporating TBI are more effective than conventional dental checkups that simply check for caries. In future, this type of checkup should contribute to improved preventative dentistry with minimal intervention.

This report describes a case of orthokeratinized odontogenic cyst arising in the mandibular molar region of a 39-year-old man. Under the initial clinical diagnosis of radicular cyst, root canal treatment was performed on the mandibular right second molar. The treatment that continued for six months did not achieve healing. Subsequently surgical intervention was selected since the tooth fracture was found, and the prognosis was judged to be poor. After atraumatic tooth extraction, the apical cystic lesion was enucleated, and the tooth was replanted. A definite diagnosis of orthokeratinized odontogenic cyst was made by histopathological examination of the biopsy specimen. The radiograph taken seven months after the operation showed an improvement in the radiolucent lesion. No clinical signs of tooth mobility, pain, and swelling were present. The tooth was then successfully retained with the final restoration. Careful follow-up is needed in order to detect any signs of recurrence.

The purpose of this study was to examine the apical foramen of root apices extracted during apicotomies. A total of 25 teeth extracted from 25 patients admitted to the Department of Conservative Dentistry at Tokyo Dental College's Chiba Hospital were used for the study. All patients were between 22 to 56 years of age at the time of the study, and each of the 25 cases was determined clinically on radiographs to be chronic apical suppurative periodontitis. Microsurgery was performed on all cases, and the extracted root apices were then observed using SEM. The results demonstrated a wide opening, greater than 350 microns as measured along the major axis, of the apical foramen in 80% of the cases. Various characteristics indicative of resorption were observed around the apical foramen. These features included those believed to have been caused by overinstrumentation during root canal treatment as well as irregularly shaped areas presumed to be apical lesions that had enlarged and eroded. We observed a high frequency of manifestations of cementum resorption surrounding the root apices of teeth with apical lesions. Furthermore, we concluded that in the majority of cases in the present study, due to the fact that the apical foramen exceeded normal opening dimensions as a result of overinstrumentation during root canal treatment or resorption around the root apex, prolongation of the lesions had occurred in response to direct contact of microbial infectious matter and tissues surrounding the root apex over a large area. The above finding suggested that, in cases in which the apical foramen is destroyed through overinstrumentation larger than #35 or in which the apical foramen opens up to dimensions greater than 350 microns due to pathologic resorption, surgical intervention may be indicated. On the other hand, in 64% of the cases, an accessory canal was observed in the root apical lesion. Based on this observation, the presence of an accessory canal in the root apex may contribute to some degree to the prolongation of the lesion.