In root canal therapy, the method of root canal obturation is selected based on the morphology of the prepared root canal. The single point obturation technique involves filling the root canal space using a single gutta-percha point in a canal that has been enlarged and shaped by reaming. However, the fit between the root canal morphology after preparation and the gutta-percha point is often poor, making it difficult to achieve a tight seal. Therefore, a root canal obturation technique that tightly fills the canal using lateral or vertical condensation of the gutta-percha point is necessary. Stainless steel files (abbreviated as SS files) are used in curved canals by applying a pre-curve, but they are prone to causing transportation at the apical potion. On the other hand, NiTi rotary files (abbreviated as NiTi files) possess superelasticity and can prevent transportation due to their excellent adaptability to curved canals; however, they have a tendency to fracture, leading to ongoing improvements over the years. Since NiTi files are used with rotational motion, the cross-section of the canal becomes circular after preparation, and the morphology matches that of the final working file. Consequently, tapered products such as 4%, 6%, and confit guttapercha point were developed, establishing a root canal filling system with high adaptability to root canal morphology. Furthermore, new materials for root canal sealer (abbreviated as RC sealer) have been developed, featuring properties such as adhesion, bonding, biocompatibility, and expansion. As a result, the single-point root canal filling method was established, which uses a newly developed RC sealer with a single gutta-percha point that fits the circular root canal formed by NiTi files. This article provides an overview of standard root canal treatment using ISO international standard instruments and the singlepoint root canal filling method, which has achieved innovative advancements.

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This study aimed to evaluate the long-term cumulative survival rates (CSR) of implants subjected to immediate loading in the molar regions, stratifying outcomes by jaws (maxilla vs. mandible), opposing dentition status, and location (free-end vs. non-free-end configurations). A retrospective cohort of 75 cases involving immediately loaded implant-supported prostheses in the maxillary and mandibular molar regions utilizing Brånemark Clone implants was followed for up to 6,522 days (approximately 17 years). Implant removal was defined as treatment failure. CSRs were calculated and compared across variables using the log-rank test, and hazard ratios (HRs) were estimated. The level of statistical significance was set at p = 0.05. The mandible had a significantly higher CSR than the maxilla (p ＜ 0.0092; HR = 5.018). Conversely, no statistically significant differences in CSR were observed when stratifying by opposing dentition conditions or free-end versus non-free-end status. Within the limitations of this 17-year follow-up study, immediate loading in the molar region yielded a significantly superior cumulative survival rate in the mandible compared to the maxilla. Opposing tooth conditions and arch positioning did not significantly impact long-term implant survival. Further investigation is warranted to analyze diverse implant systems while accounting for confounding variables, such as the number and distribution of implants and the specific design of the superstructure.

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This study sought to assess the diagnostic performance of distinct digital radiographic systems in detecting microgaps at the implant–impression coping interface. Experimental assemblies with either a controlled 0 μm-100 μm microgap or complete adaptation were irradiated at angulations of 0-25, and the resulting radiographs were evaluated by multiple calibrated clinicians. CCD-based systems demonstrated superior spatial resolution compared with IP-based systems. Diagnostic reliability remained stable in external connection implants across the tested angulations. Conversely, internal connection implants exhibited substantial interpretive variability, including false-positive gap identifications. These findings suggest that the deeply situated engagement interface characteristic of internal connection designs diminishes radiographic discernibility. The results underscore the necessity of precise beam angulation and standardized radiographic protocols to ensure accurate verification of impression coping seating during implant prosthodontic procedures.

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Oligodontia is defined as the congenital absence of six or more teeth, excluding third molars. Since April 2012, Japanese public health insurance has covered orthodontic treatment for this condition, yet clinical reports on its prevalence and characteristics remain scarce. This study surveyed eight patients (3 males, 5 females) with nonsyndromic oligodontia at an orthodontic clinic to evaluate their clinical profiles. The mean age at the initial visit was 13.1 years, with an average of 8 missing teeth per patient. The second premolars in both arches were the most frequently absent, whereas the maxillary central incisors and all first molars were most frequently present. These results indicate that the patterns of tooth agenesis in oligodontia differ from those in milder cases. Clinicians should prioritize monitoring dental development and tooth replacement sequences to facilitate early diagnosis and comprehensive treatment of oligodontia during the growth phase.

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This case report describes the successful management of severe dental discoloration using a combined minimally invasive approach involving internal and external bleaching techniques, followed by conservative restorative treatment. A 52-year-old female presented with a chief complaint of spontaneous pain and severe discoloration of #11. Clinical and radiographic examinations revealed pulpal necrosis of #11. In addition to treating the affected tooth, the patient desired comprehensive esthetic improvement and shade optimization of the entire dentition. Following successful non-surgical root canal treatment of #11, a comprehensive whitening protocol was initiated. This consisted of two sessions of internal bleaching (walking bleach) on #11, followed by a dual-whitening regimen (combined in-office and at-home bleaching) for the complete maxillary and mandibular arches. This protocol successfully harmonized the shade of #11 with the rest of the dentition, achieving significant objective brightness improvement. At the 30-month follow-up, the esthetic outcomes remained stable with minimal shade relapse. Furthermore, to address an associated esthetic concern regarding a discolored and microdontic #12, a minimally invasive lithium disilicate laminate veneer was fabricated and bonded. This combined approach successfully resolved complex anterior discoloration and structural disharmony without aggressive enamel reduction, demonstrating that a synergy of advanced whitening protocols and conservative prosthodontics can provide highly predictable, stable, and minimally invasive esthetic outcomes.

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This case report describes the clinical management of a patient with severe periodontitis, occlusal collapse, and mandibular instability, in whom the application of a mandibular implant overdenture (IOD) successfully stabilized mandibular position and enhanced oral health–related quality of life (OHRQOL). A 77-year-old female presented with a chief complaint of acute swelling and pain in the mandibular right molar region. Following clinical and radiographic evaluation, teeth with a hopeless periodontal prognosis in both arches were extracted, and interim oral function was restored immediately with complete dentures. During the healing phase, significant mandibular functional disturbances and asymmetric mandibular border movements were observed. To address this, therapeutic treatment dentures were fabricated and dynamically modified to reestablish a stable, functional musculoskeletal position. Following the confirmation of objective mandibular stability, definitive prosthodontic rehabilitation was performed, consisting of a maxillary conventional complete denture and a mandibular two-implant overdenture. At the 3-year post-insertion follow-up, the peri-implant tissues and residual ridge mucosa remained healthy, and the overall clinical course was stable. The strategic reestablishment of occlusal support and vertical dimension via therapeutic dentures promoted a symmetrical mandibular movement pathway. This comprehensive workflow reliably stabilized the mandibular position and significantly improved the patient’s long-term OHRQOL.

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Purpose: This case report describes comprehensive prosthetic treatment performed on a patient with crossbite who declined orthognathic surgery. Methods: Following a diagnostic wax-up, full-arch provisional restorations were fabricated. The jaw position, occlusal plane, and vertical dimension of the bite were adjusted using facebow transfer and electronic mandibular movement recording. To address underlying functional issues, oral myofunctional therapy̶including tongue posture guidance, deglutition training, and nasal breathing instruction̶was implemented. Pre-prosthetic partial orthodontics addressed anterior crowding. For the final restoration, a telescopic denture system was selected to ensure long-term predictability and functional stability. Results: Improvement in occlusal function, facial esthetics, and oral perioral muscle function was achieved without surgical intervention. Functional improvement was confirmed by post-treatment evaluation using a mandibular movement analyzer. Conclusion: This case demonstrates that comprehensive prosthetic treatment, combining mandibular movement analysis and oral muscle function therapy, can serve as an effective alternative when surgical interventions are not applicable.

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Introduction: Calcium hydroxide exhibits bactericidal effects and hard tissue formation capabilities. However, if the sources of infection remain beyond the bactericidal effect, hard tissue formation will not occur. Perforation makes it difficult to remove the sources of infection, leading to tooth loss due to embrittlement. Reports indicate that the success rate of perforation treatment has increased with the use of dental microscopes and bioceramics. However, if the source of infection remains, sufficient healing may not be achieved even with the use of bioceramics. Therefore, we applied a calcium hydroxide preparation to the perforation site and evaluated the infection status from alveolar bone radiolucency. Good results were obtained. We report this case with a literature review. Case: A 64-year-old female presented in 2012 with pain in the mandibular left first molar. Diffuse radiolucency was observed at the distal root apex on X-ray. Radiolucency was also observed directly below the root bifurcation. She was diagnosed with pulp chamber floor perforation and acute periapical abscess. Root canal treatment and perforation treatment were performed. A calcium hydroxide preparation was applied to the perforation site. After two months, improvement in the radiolucency directly below the root bifurcation was confirmed. Hard tissue formation was confirmed at the perforation site, and it was sealed with an adhesive material. The patient has remained asymptomatic with stable clinical findings for over 10 years.

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