Dental pulp stem cells are a kind of ecto-mesenchymal stem cells with the ability of self-renewal, multidirectional differentiation and high proliferation, which can be used as a cell source for tissue and organ repair and treatment of many diseases. In this review, the general biological characteristics of dental pulp stem cells are reviewed, and the mechanisms of osteoblast/odontoblast, myoblast/angiogenesis, and nerve regeneration as well as their preclinical applications in diabetes mellitus and ocular diseases are discussed. At the same time, combined with the latest clinical application progress of dental pulp stem cells at home and abroad, this review is aimed to provide theoretical and clinical practice reference for broader clinical application of dental pulp stem cells in the future.

Due to its strong ability of feature extraction and learning, deep learning has been proven to have significant potential in the field of artificial intelligence. We in this paper review the general concept of this technology and its application in various fields of stomatology, including image preprocessing, auxiliary diagnosis and treatment and postoperative evaluation, and explore the new direction of stomatology reform under the support of deep learning. By combining advanced algorithms and expert experience, deep learning is expected to solve challenging problems in clinical stomatology, offer clinicians intelligent auxiliary plan and support and provide new ideas for personalized diagnosis and treatment of oral diseases.

Oral and maxillofacial system consists of several components, which are mutually restricted and coordinated. Patients with dysfunction of oral and maxillofacial system system were conducted with comprehensive assessments to fully understand the static and dynamic contact state, the temporomandibular joint structure and movement coordination. This is particularly important for recognizing causes of the disease, damage to chew system especially the temporomandibular joint and disease outcome, and also lays the foundation of the follow-up treatment. In recent years, with the development of digital technology, multi-modal data fusion of the data of CT, magnetic resonance imaging (MRI) and internal oral and external oral scanning has become possible, which can help evaluate the temporomandibular joint and occlusal function more comprehensively.

Combined orthodontic and orthognathic surgical treatment is often used to correct skeletal malocclusion. The treatment process is divided into orthodontic first or surgery first, the latter can better meet patients' expectation due to the rapid change of face shape. However, some deficiencies restrict the extensive use of surgery first approach. With the development of digital technology, disadvantages of surgery first approach are gradually being improved. This research will elaborate on the development of surgery first approach, introduce our improved fully digital “accurate tooth-bone movement surgery first approach”, and put forward new indications and treatment strategies.

Entering the era of big data, more and more attention has been paid to the development and implementation of multidisciplinary approaches. In recent years, machine learning, as a branch of artificial intelligence, has been used more widely in orthodontics, and has already assisted physicians in clinical practice in many fields. Through the review of application of machine learning in three aspects: craniofacial imaging processing and analysis, orthodontic diagnosis and treatment, and related clinical research, this paper intends to explore current research status quo and project its development trend, in order to give readers a more comprehensive understanding of the application of machine learning in orthodontics.

Oral and maxillofacial trauma is a common disease in oral and maxillofacial surgery. Due to the treatment of craniocerebral trauma or limitation of regional medical technology, the optimal treatment opportunity for maxillofacial trauma may be missed. However, accurate treatment of maxillofacial trauma based on dental and maxillofacial function and facial reconstruction is a new requirement with the development of times. Relatively systematic oral and maxillofacial trauma treatment and management began in modern times, from the initial simple suture, splint ligation fixation and steel wire fixation, to titanium plate rigid internal fixation, and then to the precise restoration by digital technology. Oral and maxillofacial trauma treatment has made great progress. This paper reviews the development of oral and maxillofacial trauma, the application of digital technology, and prospects the future development trend.

Objective To establish the model of Enterococcus faecalis root canal infection in vitro and to compare the antibacterial properties of three bio-ceramic root canal sealers. Methods Forty-eight isolated anterior teeth of human single straight root canal were inoculated with Enterococcus faecalis and incubated for 4 weeks to construct an in vitro root canal infection model. After shaping and cleaning, samples were randomly divided into three experimental groups and two control groups. Each group was filled according to the following methods: A, Biodentine; B, iRoot BP; C, MTA; D, positive control group (simple cone filling); E, negative control group (sterile root canal). Samples were taken on day 1, 3, 7 and 14 respectively, and the powder after grinding off the filling material and dentin was collected. After gradient dilution, bacteria were cultured and counted. Results Compared with the positive control group, three experimental groups showed antibacterial activity against Enterococcus faecalis during four time points, which was statistically significant (P<0.05), and there was no significant difference among three experimental groups (P>0.05). In addition, germicidal efficacy of the three materials increased gradually with the extension of time, and reached the highest value in the 14^th day. Conclusion Biodentine, iRoot BP and MTA have similar antibacterial properties and can effectively kill Enterococcus faecalis.

Objective To evaluate the biocompatibility of zirconia ceramic fabricated by stereolithography. Methods According to GB/T 16886.5—2017, GB/T 16886.10—2017, YY/T 0127.14—2009 and YY/T 0127.13—2018, samples were prepared and tested with general cytotoxicity test, skin sensitization test, acute oral toxicity test and oral mucous irritation test. Results General cytotoxicity test showed that the survival rate of cells cultured for 24 h in different concentration extract groups was >90%. The degree and incidence of erythema reaction in the skin sensitization test group were equal to those in the negative control group, which proved that the ceramic material had no sensitization effect on skin. Acute oral toxicity test of rats in the experimental group showed no obvious abnormalities in gross organs and HE staining. Results of oral mucous irritation test showed that no hyperemia and erosion were observed in the cheek pouch mucosa of hamster; no dyskeratosis and vacuolar changes of basal cells were observed in HE staining, which proved that the ceramic material had no irritation on mucosa. Conclusion The biocompatibility of zirconia ceramic fabricated by stereolithography meets elementary clinical requirements.

Objective To evaluate the position change of incisor and lip after orthodontic extraction treatment in adult female patients with convex facial profiles and its correlation. Methods Thirty-nine adult female patients with convex facial profiles who received orthodontic treatment from 2017 to 2019 were selected. All subjects had undergone orthodontic tooth extraction. 3D superimpositions of CBCT scans before and after treatment, were analyzed for hard and soft tissue measurement. Results The study showed that SNA, U1-SN, UL-EP, LL-EP and naso-labial angle changed significantly after treatment. The retraction of the upper incisors was positively correlated with the degree of U1-SN and UL-EP before orthodontic treatment. There was a positive correlation between lower lip retraction and LL-EP before orthodontic treatment. Besides, the linear regression equation between the upper incisors and lip was y=0.174x+1.103(y, the retraction of upper lip; x, the retraction of upper incisors); the linear regression equation between the lower incisors and lip was y=0. 520x+1.590(y, the retraction of lower lip; x, the retraction of lower incisors). Conclusion Based on the study on superimpositions of 3D images, it is verified that orthodontists can effectively alleviate lip and facial protrusion, improve soft tissue profile, through orthodontic extraction treatment and by controlling the position of incisors in adult female patients with convex facial profiles.

Objective To evaluate serum visfatin and leptin levels in patients with periodontitis living in Xining, Qinghai Province and to explore associations between serum visfatin and leptin levels and periodontal indexes. Methods Fifty patients with periodontitis (periodontitis group) and 50 healthy periodontal patients (healthy control group) were randomly selected from from March 2019 to December 2019. Demographic and clinical data including probing depth (PD), clinical attachment loss (CAL), gingival index (GI), sulcular bleeding index (SBI) were obtained by the same senior periodontist. Serum visfatin and leptin levels were measured by enzyme linked immunosorbent assay (ELISA) technique. Results Compared with the healthy control group, the level of serum VF was higher and the level of serum LP was lower in the periodontitis group (P<0.01), and these differences were statistically significant. The level of serum VF was positively correlated with PD (r=0.97, P<0.01) and CAL(r=0.94, P<0.01). The level of serum LP was negatively correlated with PD (r=-0.86, P<0.01) and CAL (r=-0.88, P<0.01). VF and LP were not correlated with GI and SBI (P>0.05). Conclusion In periodontitis patients living in plateau section, the level of serum VF and LP is closely related to the occurrence and development of periodontitis, which can reflect the degree of periodontal tissue damage to a certain extent.

Objective To systematically review the effect of Hall technique on treating caries of primary molars. Methods Weipu Database, China Biomedicine, Web of Science, Wanfang Database, The Cochrone library, CNKI, PubMed, Embase were electronically searched from inception to May 2021. After screening literature, quality assessment and data extraction, the final analysis was performed with RevMan 5.3 software. Results Fourteen RCTs were included, including 1 169 patients and 2 021 teeth. Results of Meta analysis showed that: the success rate of Hall technique in treating deciduous molar tooth caries was equivalent to that of traditional preformed crowns (P=0.52), which was more efficient than filling treatment (P<0.01). Treatment time of Hall technique was shorter than traditional preformed crowns (P<0.01), with no statistically significant difference from filling treatment (P=0.65), the facial pain of children treated with Hall technique was lighter than that of traditional preformed crowns (P<0.05), with no statistically significant difference from filling treatment (P=0.55). Compared with Hall technique, children were more coordinating with traditional pre-coronal treatment (P<0.01), which was not statistically different from filling therapy (P=0.79). Conclusion Existing evidence shows that Hall technology may be more effective in treating deciduous molar caries, and that doctors and children respond well to treatment. However, due to the limited number of included studies, the above conclusions need to be verified by more studies.

Objective To estimate the demineralization of anterior primary teeth pretreated by NaF-chitosan gel and to discuss the potentiality of NaF-chitosan gel for early stage caries treatment. Method NaF-chitosan gel was prepared, and its basic performance observed; NaF-chitosan gel's F ion release rate was tested. Anterior primary teeth samples were prepared and divided into 4 groups randomly. Three groups were pretreated with Duraphat, NaF-chitosan gel and chitosan gel respectively. The 4th group was the blank control group. All samples were demineralized with lactic acid. The liquid was collected and its Ca²⁺ ion concentration was tested. The calcium ion concentration was measured by ion flame method. The variance of Ca²⁺ ion concentration in different groups was analyzed with SPSS 19.0. Results NaF-chitosan gel was light yellow clear liquid at room temperature. It changed into ivory jelly gel at 37 ℃. NaF-chitosan gel could release fluorine ion 70.22% in 4 h. There was no difference between NaF-chitosan gel (4.29 mg/L) and gold standard duraphat (4.22 mg/L) in reducing demineralization by lactic acid. The Ca²⁺ ion concentration was much lower in NaF-chitosan gel group than in chitosan gel (7.20 mg/L) and control group (7.34 mg/L) (P<0.05). Conclusion NaF-chitosan gel can improve the anti-acid ability of enamel in anterior teeth, and it can be used to prevent early caries of anterior teeth.

Implant-supported fixed denture is a safe and effective method for edentulous jaw restoration. Photogrammetry technology has been applied to the digital impression of oral implants, which can virtually transfer the implant position in patient's mouth to a computer-aided design software program and be used to make implant-supported prostheses. This paper reports a case of edentulous maxillary immediate implant and immediate restoration with ICam4D photogrammetry system, and reviews the literature from aspects of technical principles, technical advantages and application limitations of photogrammetry system.

Calcitonin gene-related peptide (CGRP) is a neuropeptide secreted by nerve endings. In recent years, it has attracted much attention because it has been found to be a key factor in nerve regulation of bone remodeling and is related to the remodeling of blood vessels and collagen fibers. During orthodontic tooth movement (OTM), the remodeling of the local periodontal microenvironment includes alveolar bone, periodontal ligament, gums and also mainly covers nerves, blood vessels, collagen and bone tissues. Exploring the specific mechanism of CGRP regulating nerve, bone, blood vessel, and collagen remodeling is particularly important for understanding the remodeling of microenvironment during orthodontic movement, but the specific mechanism is not yet fully understood. This article reviews its research progress.

Ectodermal hypoplasia (ED) is a group of congenital genetic diseases caused by ectodermal structural hypoplasia, which can be characterized by hypohidrosis, the scarcity of hair, abnormal nails, congenital lack of teeth or no teeth. Most patients have the typical symptoms of congenital missing teeth or edentulous jaws, but clinical treatment methods for the restoration of missing teeth are different at present and there is no relevant consensus guidance. This review summarizes the oral clinical treatment of ectodermal dysplasia from the aspects of the restoration of missing teeth and the improvement of maxillofacial appearance in patients with ectodermal dysplasia, in order to provide more standardized and comprehensive oral treatment and intervention programs for patients.

Dentin hypersensitivity is a common symptom in the field of stomatology. There has been no ideal treatment method at present. Among all treatment methods, laser desensitization is accurate and clear, and the response is rapid, which has attracted widespread attention. Nd:YAG laser is the most widely used laser. This article summarizes the specific mechanism and application progress of Nd:YAG laser treatment of dentin hypersensitivity, hoping to provide reference for clinical application and scientific research.

Periodontitis is a common oral inflammatory disease. An enormous amount of literature has reported that periodontitis is closely related to systemic diseases, such as cardiovascular disease, type 2 diabetes, premature low-birth weight infants and so on. Periodontitis and prostate diseases have similar risk factors. Age, smoking, obesity and diabetes, as well as inflammatory stimulation, have a significant impact on the disease. This article mainly reviews the research status of the relationship between periodontitis and prostate diseases, common influencing factors, and related biological mechanisms.