Vertical root fractures are frequently challenging to diagnose in their early stages. However, cemental tears, which exhibit similar clinical manifestations, are often associated with a more favorable prognosis compared to VRFs. Therefore, early and accurate differential diagnosis between these conditions is of critical importance. In recent years, advances in treatment modalities for Vertical root fractures—particularly in root canal-based adhesive techniques—have contributed to improved clinical outcomes. The long-term prognosis is influenced by multiple factors, including the extent of preoperative bone defects and the magnitude of postoperative occlusal loading. Notably, in cases without such unfavorable conditions, a 10-year survival rate exceeding 90% has been reported. These findings indicate that, with accurate diagnosis, appropriate case selection, and proper treatment, Vertical root fractures can achieve a clinically acceptable and predictable long-term prognosis.

Among the surgical approaches to prosthetic replacement, tooth transplantation and replantation are excellent treatment methods with low ethical barriers due to the use of autologous materials and high patient benefits. This requires general knowledge of transplant medicine and the accumulation of information (dental examination) obtained from the preceding permanent tooth, donor tooth, and surrounding periodontal tissue, making it a highly predictable treatment method. The key point is to classify the contact surfaces of the donor tooth and the graft bed into pathological surfaces (Morbid Surface) and healthy (non-infected) surfaces (Intact Surface), and which surfaces are placed in contact with which is the key. This article provides an overview and presents case studies.

Root fracture is a condition frequently encountered in usual clinical practice, and it goes without saying that managing with the pathology can be challenging. The primary approach to treating root fracture is adhesion of the fractured site, but under certain conditions, intentional replantation may be indicated as an alternative. On the other hand, when extraction of a fractured tooth is required, if the patient has a healthy wisdom tooth and meets the necessary criteria, tooth autotransplantation may be considered; otherwise, general prosthetic treatment for the missing tooth is selected. In this article, I would like to express my humble opinion about prosthetic treatment strategies for root fractures, dividing them into 1) cases when the fractured tooth is preserved and 2) cases when the fractured tooth is extracted, with actual clinical cases.

In the context of functional rehabilitation utilizing removable partial dentures (RPDs), denture stability is a critical prerequisite. Denture stability is influenced by several factors, including (1) abutment tooth selection, (2) components such as retainers, and (3) denture base outline—factors that can be regarded as “static factors” within the target dental arch. Additionally, (4) the occlusal relationship with the antagonists and (5) the patient’s occlusal force constitute “dynamic factors” that also influence denture stability. The static factors pertain to the RPD design itself, which must be determined by dentists and accurately communicated to dental technicians. However, even if the RPD is appropriately designed, insufficient communication between the dentist and technician may result in denture dysfunction. This article focuses on the static factors within the target dental arch and discusses the specific information that must be shared from the dentist to the dental technician to ensure the fabrication of well-functioning RPDs.

It is very important to understand the features of partially edentulous arches. Kennedy classification is used to classify each partially edentulous arch, and Cummer classification is used to classify the relationship of occluding condition. These are also used to diagnose supporting conditions and occluding factors. The proper designs of rest and rest sheet, and guide plane and proximal plate are basic concepts and can contribute to better functions. It is critical to share information and collaborate with dental technicians for well-functioning removable partial dentures.

Randomized controlled trials (RCTs) are considered as the study design with the highest level of evidence. However, it is often challenging to conduct large-scale and long-term RCTs, and the generalizability of the findings from RCTs is limited. In contrast, recent advances in epidemiologic theory and the accumulation of large-scale data have increased the value of evidence derived from observational studies. RCTs and observational studies have different advantages and disadvantages. Therefore, it is important to understand their characteristics. This article introduces observational studies in dentistry and explains key points for increasing the value of evidence derived from observational studies.

Alveolar ridge augmentation can generalize difficult prosthetic treatment and improve the predictability of treatment. However, in order to realize safe and reliable regeneration of the alveolar ridge, detailed protocols must be drawn up in accordance with various laws and based on accurate evidence, and manufacturing methods for transplantation agents must be established. The fact that many regenerative medicines using blood concentrates are provided in the field of dentistry in Japan indicates that there is a high need for regenerative medicine. The authors have previously identified the causes of the low adipogenic differentiation potential of mesenchymal stem cells derived from jawbone marrow and various predictive markers of bone formation in vivo for transplanted cells. The authors have developed a novel bone regenerative agent that combines specialized cell sheets with scaffolds, with the aim of applying it to clinical practice.

This article provides a comprehensive review, based on existing literature, of the utility of single-retainer resin-bonded fixed dental prostheses (RBFDPs) and endocrowns, modalities developed in line with the Minimal Intervention (MI) concept. The single-retainer RBFDPs utilize only one abutment tooth, minimizing the removal of tooth structure. Evidence suggests a more favorable long-term prognosis for this design compared to conventional two-retainer prostheses. Meanwhile, the endocrown is a post-free restoration for non-vital teeth that gains retention from the morphology of the pulp chamber, thereby reducing invasive procedures on the root and conserving enamel. The clinical success of both treatments depends on appropriate case selection, a thorough understanding of material properties, and meticulous adhesive techniques. Consequently, these restorations are anticipated to become standard options in the future for prosthodontic treatments.

Purpose: This study aimed to determine the usefulness of machine learning techniques, specifically supervised and unsupervised learning, for assessing the cementation condition between a fixed partial denture (FPD) and its abutment using a resonance frequency analysis (RFA) system.

Methods: An in vitro mandibular model was used with a single crown and three-unit bridge made of a high-gold alloy. Two cementation conditions for the single crown and its abutment were set: cemented and uncemented. Four cementation conditions were set for the bridge and abutments: both crowns were firmly cemented, only the premolar crown was cemented, only the molar crown was cemented, and both crowns were uncemented. For RFA under cementation conditions, 16 impulsive forces were directly applied to the buccal side of the tested tooth at a frequency of 4 Hz using a Periotest device. Frequency responses were measured using a 3D accelerometer mounted on the occlusal surface of the tested tooth. Both supervised and unsupervised learning methods were used to analyze the datasets.

Results: Using supervised learning, the fully cemented condition had the highest feature importance scores at approximately 3000 Hz; the partially cemented condition had the highest scores between 1000 and 2000 Hz; and the highest scores for the uncemented condition were observed between 0 and 500 Hz. Using unsupervised learning, the uncemented and partially cemented conditions exhibited the highest anomaly scores.

Conclusions: Machine learning combined with RFA exhibits good potential to assess the cementation condition of an FPD and hence facilitate the early diagnosis of FPD retention loss.

Patient: A 52-year-old female presented to our hospital with a chief complaint of difficulty chewing due to tooth eruption and tooth movement. Teeth diagnosed with severe periodontitis that could not be retained were extracted, while maintaining occlusion with treatment dentures. Four implants were placed in the maxilla and six implants were placed in the mandible, and fixed final prostheses were installed.

Discussion: Cleaning instructions were given to the patient and the morphology was modified while using the provisional restorations to improve not only function and esthetics but also cleanability, which was reflected in the final prostheses and was considered to have led to a good prognosis.

Conclusion: Treatment with implant-supported fixed prostheses using stepwise provisional prostheses improved the oral health-related quality of life in a patient with masticatory disturbance due to severe periodontal disease.

Patient: The patient was an 84-year-old woman who came to our hospital with the chief complaint of difficulty with mastication. There was only one remaining occlusal support, and the dentures she was wearing had poor form and occlusion. She was diagnosed with a masticatory disorder due to ill-fitting dentures.

Discussion: The remaining teeth were connected by prosthetics to distribute the load and occlusal support in the molar area was established with dentures, because it was predicted that the loss of occlusal support would lead to a transition to non-vertical stop occlusion. As a result, there were no problems with the abutment teeth or prosthetic device and the outcome was also favorable according to subjective and objective evaluations at 3 years after the treatment.

Conclusion: Full-arch prosthetic treatment not only improved functionality but also prevented transition to non-vertical stop occlusion, thereby contributing to an improvement in the patient’s QOL.

Patient: A 67-year-old female presented with a chief complaint of poor denture retention. She had an edentulous mandible with severe residual ridge resorption. Piezography was used to evaluate the denture space, and a denture was designed in harmony with orofacial muscular function to improve mandibular denture retention.

Discussion: Piezography enabled the arrangement of artificial teeth within the functional denture space, and the denture base was extended to its maximal physiologically acceptable extent. This approach likely achieved both physical and physiological retention, resulting in improved stability and masticatory function of the mandibular denture.

Conclusion: Using piezography, a denture in harmony with orofacial muscular function and resistant to dislodgement during use was fabricated for an edentulous patient with severe mandibular ridge resorption, resulting in a favorable clinical outcome.