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Dentin dysplasia type Ⅱ (DD-Ⅱ) is a subtype of hereditary dentin disorders. The dentin sialophosphoprotein (DSPP) gene has been revealed to be the causative gene, whose mutations could affect the normal tooth development process. The lesions involve both deciduous and permanent dentition, mainly manifested as tooth discoloration, attrition and even the subsequent malocclusion. If not treated in time, it will significantly affect the physical and psychological health of patients. The disease is difficult to be diagnosed in clinic accurately as its low incidence and hidden manifestations. The present article aims to discuss the clinical and radiographic characteristics, diagnosis, treatment of DD-Ⅱ, in order to improve the overall understanding on DD-Ⅱ for clinicians.

The biological samples of oral genetic diseases and rare diseases are extremely precious. Collecting and preserving these biological samples are helpful to elucidate the mechanisms and improve the level of diagnose and treatment of oral genetic diseases and rare diseases. The standardized construction of biobanks for oral genetic diseases and rare diseases is important for achieving these goals. At present, there is very little information on the construction of these biobanks, and the standards or suggestions for the classification and coding of biological samples from oral and maxillofacial sources, and this is not conducive to the standardization and information construction of biobanks for special oral diseases. This consensus summarizes the background, necessity, principles, and key points of constructing the biobank for oral genetic diseases and rare diseases. On the base of the group standard "Classification and Coding for Human Biomaterial" (GB/T 39768-2021) issued by the National Technical Committee for Standardization of Biological Samples, we suggest 76 new coding numbers for different of biological samples from oral and maxillofacial sources. We hope the consensus may promote the standardization, and smartization on the biobank construction as well as the overall research level of oral genetic diseases and rare diseases in China.

Circadian rhythm is regulated by circadian clock, which is formed by the body response to external cyclic stimuli through the endogenous circadian clock. Circadian rhythm disturbance is closely related to the risks of a variety of diseases, and its impact on oral health cannot be ignored. Exploring the relationship and related molecular mechanism between circadian rhythm and dental hard tissues development are helpful to deeply understand the pathogenesis of developmental defects on these tissues, which could provide a theoretical basis for prevention and treatment on disorders of dental hard tissues. In order to provide guidance for the disease prevention and treatment, based on the summarization of current research progress, this paper focuses on the involvement of biorhythm in the development of tooth hard tissues as well as the disturbance of circadian rhythm on the formation of enamel and dentin, and analyzes the related regulating mechanism of circadian rhythm and genes during the development of tooth hard tissues.

Diabetes mellitus is a relative contraindication of dental implant therapy, that limits the application of implant therapy severely. Diabetic status often leads to secondary vascular and bone lesions, which affect treatment adversely and lead to an increased failure rate. Therefore, how to implement implant therapy for diabetic patients has become a difficult question for dentists. According to the research and experience over the years on diabetic patients, and referring to the current research progress on this topic, the authors will discuss the clinical characteristics of diabetic patients and the details of treatment process, for reference.

Objective: To investigate the effect of guided bone regeneration (GBR) on marginal bone loss (MBL) in the region of the mandibular posterior tooth by using a retrospective cohort study, in order to provide reference for clinical practice. Methods: The research subjects were patients who received dental implants from October 2008 to June 2011 in the region of the mandibular posterior tooth at the Department of Oral Implantology, School of Stomatology, The Fourth Military Medical University. According to whether GBR was performed or not and the time of implant insertion, the patients were divided into the controls group (patients without bone grafting), simultaneous GBR implantation group, and delayed GBR implantation group. On this basis, the MBL was measured according to radiographs by comparing the marginal bone level from that of immediate postoperation 10 years ago. General data was collected and compared among groups, including modified plaque index (mPI), modified sulcus bleeding index (mSBI), probing depth (PD), and gingival papilla height. Results: The controls group (patients without bone grafting), implantation group, and delayed GBR implantation group followed 58, 76, 26 implants in 26, 32, 13 patients aging at (46.5±9.9), (45.5±10.7), (58.3±6.4) respectively. The duration of the follow-up was (11.2±0.7), (11.1±0.8), (11.1±0.9) years respectively. The 10-year implant survival rate was 100% (58/58), 100% (76/76), 100% (26/26). The MBL was (0.91±0.28), (0.84±0.27), (1.01±0.27) mm respectively. The MBL difference of patients with simultaneous GBR implantation and delayed GBR implantation showed statistical significance ( P <0.05), but these two groups showed no statistical significance compared with the controls group ( P >0.05). The mPI, mSBI, PD, and gingival papilla height of the three groups all had no significance on statistics ( P >0.05). Conclusions: It can be concluded that there is no difference in long-term marginal bone resorption between simultaneous and delayed implantation with or without GBR (using autologous blood mixed with granular bone meal) in the posterior mandibular area.

With the development of dental implant prosthodontic technique, many new concepts and methods have emerged. In the light of present situation, implant prosthodontic technique is developing towards precision, comfortability, immediacy and digitization. Meanwhile, the research area is focusing on expanding immediate restoration indications, clinical selection strategies of different prosthodontic materials and the accuracy of digitalized prosthodontics. The paper aims to discuss the developing trend in prosthodontics of dental implantology for clinical reference.

Developmental disorders of dental hard tissues are important components of non-carious diseases, which mainly include amelogenesis imperfecta and hereditary dentin disorders with various subtypes. In the absence of effective intervention, these disorders would lead to tooth sensitivity, defects of tooth structure or even loss of tooth, affecting the masticatory function and facial aesthetic configuration. At present, many dental clinicians may not have sufficient understanding of the diseases, and it is urgent to pay attention to the diseases per se and the patients affected. Based on the summary of the current research progresses, this article focuses on the clinical classification, the disease phenotype and the pathogenesis of gene mutations, in order to provide reference and help for the dental clinicians as well as the patients.

Objective: To evaluate the effect of semaphorin 3A (Sema3A) pre-treated bone marrow mesenchymal stem cells (BMSC) sheets on new bone formation in type 2 diabetes mellitus rats. Methods: Type 2 diabetes mellitus (T2DM) were induced by injection of streptozotocin, and the BMSC were isolated, controlled, identified and induced into cell sheets. Fifteen T2DM rats were randomly divided into control, sheets and Sema3A-sheets group and the calvarial critical size defect (CSD) model of rats were established. The defect zone of rats from control group were implanted with bone powder. The defect zone of rats from sheets group were implanted with bone powder and BMSC sheets. The defect zone of rats from Sema3A-sheets group were implanted with bone powder and BMSC sheets pretreated with 1.0 mg/L Sema3A. After 8 weeks, the bone samples were harvested and analyzed by micro-CT scanning, HE staining for the evaluation of new bone formation, and the immunohistochemical analysis for the expression of osteogenesis-related proteins including type Ⅰ collagen (COL- Ⅰ ), bone morphogenetic protein-2 (BMP-2), and osteocalcin (OCN). Results: The BMSC were isolated and cultured, and oil red O and Alizarin red S staining proved the multi-potential differentiation. Eight weeks after the establishment of calvarial CSD model, Sema3A-sheet group showed the most abundant new bone formation (0.516±0.070), with increased bone volume fraction, namely bone volume/tissue volume (BV/TV) compared with sheets group (0.319±0.050) and control group (0.224±0.037) ( P <0.05), and the sheets group showed increased BV/TV compared with control group ( P <0.05). While trabecular thickness (Tb.Th) control group showed no difference in three groups ( P >0.05). HE staining also confirmed that Sema3A-sheets group showed the most new bone formation. Sheet group (0.174±0.051) compared showed difference with control group (0.099±0.033) ( P < 0.05), and Sema3A-sheet group (0.421±0.069) showed increased bone formation compared with sheet group and control group ( P <0.05). Immunohistochemistry showed that BMSC sheet increased the expression of osteogenesis-related proteins including COL-Ⅰ, BMP-2 and OCN, while Sema3A pretreatment showed more obvious increase of the expression of COL-Ⅰ and OCN. Conclusions: The combined implantation of bone powder and Sema3A stimulated BMSC sheets significantly increased bone regeneration in vivo . Therefore, Sema3A pre-treated BMSC sheets transplantation provides a new strategy for restoring bone defect in T2DM.

The implant prosthesis has been extensively used in clinic recently, and implant failure is appearing. Many factors may cause the failure, and they work together generally. This paper summarizes and analyzes the failure cases related to implant treatment and relevant risk factors of oral implants in Department of Implantation, School of Stomatology, The Fourth Military Medical University during the past six years, in order to improve the success rate of implant prosthesis and provide guidance for clinical application.

At present, dental implant technology with high chewing efficiency and good appearance in esthetics has been widely used. However, some problems may be found in the follow-up procedure of implant prostheses, and one of them is food impaction. This article discussed the causes of food impaction in the posterior region with implant prostheses and provided treatment strategies to this biological complication.