Objective To explore SD rat bone marrow mesenchymal stem cells (BMSCs) induced by combined application of vascular endothelial growth factor (VEGF) and plateletderived growth factorBB (PDGFBB); to explore its feasibility in vivo and the expression of related angiogenesis, after bone marrow mesenchymal stem cells cell membranered antler powder/PVA scaffold is replanted in animals. Methods Thirtysix 10weekold male SD rats were selected and their weight was controlled at (250±30)g, and they were randomly divided into 3 groups, each with 12 rats. The 3D printed red deer antler powder/PVA scaffold was replanted into the rat kidney capsule, and then gross observation, HE staining, blood vessel count and RTPCR were performed. The animals were classified into 3 groups, experimental group:growth factor induced BMSCs patchstent complex; control group:BMSCs patchstent complex; blank group:no materials were transplanted after modeling. Results After replanting, the expression of factors related to angiogenesis, hypoxia inducible factor1α (hypoxia inducible factor1α, HIF1α), angiopoietin1 (angiopoietin1, Ang1), hepatocyte growth factor (HGF) and insulinlike growth factor1 (IGF1), were all increased (P＜0.05) in experimental group. The HE staining showed obvious angiogenesis in the experimental group. The number of blood vessels in the experimental group was higher than that in the control group. Conclusion The BMSCs membranered antler powder scaffold induced by VEGF and PDGFBB can effectively promote the formation of new blood vessels and contribute to the vascularization of tissue engineered bone.

Objective To study oxidative stress antibacterial mechanism of rare earth nanomaterial Ce/Ag/ZnO against oral Saccharomyces albicans. Methods Bacterial plate culture, bacterial growth curve drawing and scanning electron microscopy (SEM) and oxidative stress related biochemical indexes detection and other experimental methods were adopted. Results The MIC and MBC of Ce/Ag/ZnO on Saccharomyces albicans were 0.156 mg/mL and 0.313 mg/mL, respectively. SEM showed that the bacteria crumpled and collapsed; the contents leaked; the cell membrane was seriously damaged. The level of reactive oxygen species (ROS), the degree of lipid peroxidation (LPO) and the activity value of catalase (CAT) of bacteria were significantly increased (P＜0.05). Conclusion This experiment proves that nanomaterials modified by rare earth still have good antibacterial effect, and reveals their antibacterial mechanism of inducing oxidative stress reaction inside saccharomyces albicans. This provides theoretical support for the application of this material in the manufacture of denture base and for the prevention of denture stomatitis in the future.

Objective To study the effect of naringin solution with different concentration on the remineralization of early enamel caries. Methods Models of early enamel caries of human premolars were established by external demineralization method. The samples were remineralized with different concentrations of naringin solution, NaF and deionized water (DW) as positive and negative controls, respectively. The changes of image and the ratio of calcium and phosphorus of melt surface before and after demineralization were observed by electron probe and Xray energy spectrometer. Results The results of electron probe showed that the enamel surface of the deionized water group showed a typical demineralization, which was a honeycomb loose structure. The NaF group could form a uniform spherical sedimentary area. Irregular sediments covered the honeycomb surface of the demineralization in naringin solution groups, and with the increase of concentration, the sediments gradually changed from porous to dense. The Ca/P in the experimental group was lower than that in the NaF group (P＜0.05). The Ca/P in the 1, 10, 20 and 50 mg/mL naringin solution groups was similar to that in the DW group, and the difference was not statistically significant. Compared with 1, 10 mg/mL naringin solution groups and DW group, 100 mg/mL naringin solution group had statistical significance (P＜0.05). Conclusion Different concentrations of naringin solution can promote the remineralization of early enamel caries, and the effect of naringin solution increases with the increase of concentration.

Objective To retrospectively analyze the clinical effect of implantsupported fixed dental prostheses in patients with edentulous maxillaries. Methods A total of 109 implants in 20 patients with edentulous maxillaries in the Affiliated Stomatological Hospital of Nanjing Medical University from January 2017 to January 2020 were reviewed. Panoramic radiographs were taken immediately after the operation and during the followup, and the implant survival rate and periimplant marginal bone loss (MBL) were observed and compared. The clinical effect was measured by the OHIPEDENT questionnaire (Oral Health Impact ProfileEDENT) and a visual analog scale (VAS), and SPSS software was used for descriptive statistical analysis. Results During the followup, 3 out of 109 implants were removed due to the failure of osseointegration, and the implant survival rate was 97.24%. The MBL was about 0.74 mm/year; the average score of the OHIPEDENT questionnaire was 8.00, and the VAS score was 9.15 on average. Conclusion The shortterm clinical effect of maxillary edentulous implantsupported fixed dental prostheses is stable, and patient satisfaction is high.

Objective To observe the longterm clinical outcome of the resin restoration plus multiple coronally advanced flap technique (MCAF) for the treatment of gingival recession associated with noncarious cervical lesion (NCCL). Methods Three patients with multiple gingiva recession with NCCL were selected, and the resin restoration + MCAF combined with subepithelial connective tissue graft (SCTG) was performed to repair the soft and hard tissue defects. Pocket depth (PD), bleeding index (BI), plaque index (PLI), recession height (RD), keratinized tissue width (KTW) and gingiva thickness (GT) were measured at baseline and followup 3year after treatment and the root coverage esthetic score (RES) was calculated. Results Totally 3 patients and 10 sites were treated. The mean PD at baseline and followup were (1.10±0.32) mm and (1.65±0.34) mm, P=0.001. The mean BI at baseline and followup were (0.10±0.32) and (0.50±0.53) mm, P=0.037. The mean PLI at baseline and followup were (0.30±0.48) mm and (0.40±0.52) mm, P=0.660. All sites achieved 100% root coverage and significant augmentation of KTW and GT, and the P value was ＜0.000, 0.003 and ＜0.000. The mean RES at 3year followup was 9.40±0.95. Conclusion The resin restoration plus MCAF could efficiently repair the soft and hard tissue defects caused by NCCLs, and present a great esthetic outcome.

Objective Based on cone beam computed tomography (CBCT), the distribution and related data of bifid mandibular canals were studied, so as to provide guidance and basis for clinical practice. Methods Fourhundred adult people (800 sides of mandible) in Shanxi Province were taken CBCT to measure and analyze the prevalence, length, diameter and angle of bifid mandibular canals, and to explore the influence of gender, left and right sides and different age groups on bifid mandibular canals. Results The incidence of bifid mandibular canal was 40.75% (163/400), which occurred in 248 sides (31.0%). In the classification of bifid mandibular canals, the proportion of retromolar canal, dental canal, forward canal and buccolingual canal was 45.97%, 23.39%, 28.63% and 2.02%, respectively. The average diameter and length of bifid mandibular canals were（1.18±0.36）mm and（12.58±4.72）mm respectively, and the average angle with the main mandibular canal was (42.46±18.14)°. Conclusions The incidence of bifid mandibular canal is high in adults in Shanxi Province, especially in the posterior molar area. CBCT should be taken to estimate the risk before surgery, so as to avoid serious complications caused by intraoperative injury.

Objective To perform occlusal contact analysis using a digital model and guide occlusal adjustment and reconstruction. To evaluate the application value of digital technology in treating food impaction. Methods Seventyfour patients with vertical food impaction were randomly divided into two groups. In the experimental group, the information about anatomical morphology and occlusal relationship of teeth was obtained by using an oral digital impression scanner to generate a digital model. The food impaction was analyzed and diagnosed according to the contact distribution and intensity in the occlusal contact area shown on the digital model. In the control group, occlusal contact was checked with occlusal paper. Patients in both groups were treated with occlusal adjustment and minimally invasive repair to improve occlusal contact. Clinical effect was evaluated one month after operation. The overlap rate of occlusal contact sites between the two methods was counted. Results The effective rate of treating food impaction was 94.59% in the experimental group and 97.30% in the control group, and there was no statistical difference between them (P＞0.05). The overlap rate of occlusal contact site between the two methods was 95.7%. Conclusion Using digital model to analyze and diagnose food impaction is simple and intuitive, which can accurately guide occlusal adjustment and occlusal contact reconstruction.

Objective To evaluate the clinical effect of miniscrews combined with NiTi segment arch on the longdistance mesial movement of the mandibular second and third molars to close the extraction space of first molars. Methods Sixteen cases with severe caries of mandibular first molar, healthy second molar and third molar were selected. The mesial and distal roots of mandibular first molar were extracted in different stages. Miniscrew was used to provide anchorage, and NiTi segmental archwire was used to provide single couple and double couple for realizing bodily movement of molars in the space closing. Graphpad prism 6.0 software package was used for paired t test with data collected before and after treatment. Results All the second molars moved in place and a good occlusal relationship was established. There was no significant difference in the axis of the second molar and mandibular incisor and the probing depth after treatment. Ten third molars moved in place by themselves and another 6 cases were assisted by local segmental archwire. Conclusion The miniscrews combined with NiTi segment archwire can provide the necessary force and moment to realize mesial bodily movement of the molars.

Objective To measure the morphological chin characteristics of skeletal Class Ⅰ adult females with congenital absence of mandibular incisors by conebeam computed tomography, and investigate the effect on chin morphology. Methods According to the inclusion criteria, CBCT data of 113 adult female patients before treatment were selected, and were divided into study group (60 cases) and control group (53 cases) for the measurement and statistical analysis of line, space area and volume. Results There were statistically significant differences in chin, mandible development and facial aesthetic evaluation between the study group and the control group. In the study group, the comprehensive and transverse length of the mandible, the alveolar bone width between the lower canines, the volume of the alveolar process above the chin process, the development of the mandible in front of the mental foramina and the sagittal sectional area of the mandible were weaker than those of the control group. The Po point was relatively far from the facial plane. Conclusion Congenital absence of mandibular incisors impacts the development of mandible, mainly on the transverse growth of lower anterior alveolar process and the overall development of the mandible. The chin volume is not significantly affected, but the convexity increases relatively, which results in a better evaluation for the facial profile.

Oral mucosal traumatic ulcer is a common type of oral ulcer in infants and adolescents. Nervous system disease is a rare cause of the disease. This article reports on the diagnosis and treatment of a case of severe intractable oral mucosal traumatic ulcers in a 2 years and 9 months old child with athetosic cerebral palsy. Combined with the literature, we discussed similar cases, the underlying mechanism and the characteristics of clinical diagnosis and treatment, and emphasized the importance of removing traumatic factors and strengthening monitoring and behavior management in the treatment of severe and refractory traumatic oral mucosal ulcers in infants and adolescents.

Deficiency of bone height in the posterior maxilla is one of the common problems in implant surgery. Maxillary sinus floor elevation expands indications for implanting in the posterior maxillary area. With the progress of clinical technology and the development of oral materials, the bone grafting strategy of maxillary sinus floor elevation surgery has been constantly updated. Although the mechanism of maxillary sinus floor osteogenesis has not been fully elucidated, there is increasing recognition of maxillary sinus lifting without bone grafting. How to select and grasp indications is the key to this strategy. Traditional bone graft materials have different degrees of defects. Therefore, new bone graft auxiliary materials emerge as the time requires, and some of them have been used in clinic. This paper reviewed the research progress on bone augmentation strategy of maxillary sinus floor elevation.

Occlusal splint is a commonly used method for treating bruxism. By mechanically isolating the direct contact between maxillary and mandibular teeth, relaxing the masticatory muscles and eliminating occlusal interference, it can effectively reduce the symptoms of bruxism and its damage to the function of stomatognathic system. There are many kinds of occlusal splints in clinical practice. Different manufacturing methods, coverage area, materials and occlusal contact modes bring different treatment outcomes. Especially with the development of digital technology, biofeedback technology and artificial intelligence technology, researches on new occlusal splints have gradually become a hotspot. In this paper, the characteristics of different types of occlusal splints and their clinical effects on treating bruxism were reviewed. It is proposed to provide suggestions for clinical selection of appropriate occlusal splints for bruxism and to enlighten future clinical researches.

Oral cavity is a complex biological environment where a variety of bacteria exist. Flora imbalance will lead to various oral diseases. Many scholars have found that graphene and its derivatives have strong antibacterial effects on the pathogens of common oral diseases, so it can be used as a new type of antibacterial material in oral cavity. This paper mainly reviews the antibacterial mechanism of graphene and its derivatives, and summarizes its antibacterial applications in stomatology.

Periodontitis is one of the most common diseases in stomatology. It involves periodontal supporting tissues. As the disease progresses, it will cause attachment loss, periodontal pocket formation, alveolar bone resorption, and eventually tooth looseness and loss. Since the alveolar bone damaged and absorbed by periodontitis has very limited selfhealing ability, the goal of periodontitis treatment is to get as much periodontal tissue regeneration as possible on the basis of completely removing the plaque biofilm. Periodontal ligament stem cells are widely studied as the most suitable cells for periodontal tissue regeneration. Wnt signaling pathway can be divided into canonical Wnt pathway and noncanonical Wnt signaling pathway, which are very complex and highly conservative pathways. This pathway is closely related to the osteogenic differentiation of periodontal ligament stem cells which is important for periodontal tissue regeneration. This article reviewed the research status of canonical Wnt signaling pathway and the osteogenic differentiation of periodontal ligament stem cells.

Dens invaginatus is a developmental malformation in dental morphology. The complex anatomy of affected teeth can make diagnosis and endodontic management challenging. The diagnosis, treatment and prognosis of dens invaginatus has made progress with the application of threedimensional imaging techniques such as cone beam CT combined with digital software in endodontics. Advanced treatment options such as dental operation microscope, ultrasonic technology and biomaterials bring hope for maintaining pulp vitality and teeth that could not be saved before. Treatment depends on the clinical symptoms, pulp infection, complexity of invagination, development of apical and periapical tissue destruction. The aim of this article is to review the etiology, prevalence, classification, diagnosis and management of teeth affected by dens invaginatus. Emphasis will be placed on its classification and treatment.

Primary failure of eruption (PFE) is a rare abnormal tooth eruption disorder, which is caused by an abnormal mechanism of tooth eruption rather than other local or systemic factors. The pathogenesis is not very clear and may be related to gene mutations. Mutation of parathyroid hormone receptor 1 (PTH1R) is one of the proven etiologies. The clinical manifestations are mainly characterized by incomplete tooth eruption and posterior teeth open bite. Orthodontic extrusion is ineffective. Due to its obvious family aggregation, genetic analysis is a necessary auxiliary examination method, which is of great significance to the screening, diagnosis and treatment of PFE. There is no effective treatment method for PFE at present. Removable partial denture, implant denture and surgical treatment are available for reference. The aim of this study is to systematically evaluate the pathogenesis, clinical characteristics, diagnosis and treatment of PFE.

Tumor associated macrophages (TAMs) are important immune cells and inflammatory cells in tumor microenvironment, and play an important role in the initiation, progression, invasion and metastasis of human cancers. In this essay, the origin, polarization of TAMs and their clinical effect on oral cancer and precancerous lesions are discussed. The role of TAMs in cancer invasion and metastasis is also studied, in order to provide new ideas and strategies for OSCC research and treatment.

Patients with atrophic posterior maxilla challenge implant surgeons for the low bone quality and quantity. In recent years, pterygoid implants have gained extensive attention, and have vast potentials as an alternative for the rehabilitation of atrophic posterior maxilla. Pterygoid implants with no need of grafting, avoid related complications, reduce the treatment cost and shorten the treatment cycle. Pterygoid is the dense bone which provides ideal primary stability for implants and avoids the biomechanical overload risk caused by cantilever, showing more successful clinical effects. This article reviews related anatomy, indications, insertion methods, immediate loading and complications of pterygoid implants.