Understanding the etiology and mechanism of early malocclusion and the characteristics of craniofacial growth and development is a necessary prerequisite for scientific early treatment. Clarifying the basic principles of early orthodontic treatment is conducive to the coordinated development of the orognathic system.In order to improve the success rate of early treatment and reduce the difficulty of orthodontic sequential treatment in the future, it is necessary to identify indications of temporary malocclusion and early treatment with bad prognosis. This article starts from the basic concept, in order to provide guidance for clinical practice.

Objective To investigate the effects of fiber surface deposited with silicon dioxide films by atomic layer deposition on properties of dental fiber-reinforced composites. Methods SiO₂ films were deposited on the surface of quartz fiber by atomic layer deposition(ALD). Then the quartz fiber was used to manufacture fiber resin composites, which were divided into four groups: A(no soaking agent removal), B(soaking agent removed), C(soaking agent removed and silanization), and D(soaking agent removed, 600 ALD cycles performed and then silanization). Scanning electron microscopy, water contact angle test, hygroscopicity test, CCK8 test and three-point bending test were used to investigate the properties of fiber resin composites. Results The surface morphology of the quartz fiber treated by ALD was smooth and had no obvious change compared with that before treatment. Moreover, the quartz fiber showed hydrophobicity after silanization. The results of three-point bending test revealed that the mechanical properties of fiber-resin composites modified by ALD were significantly improved(P<0.05). When viewed by scanning electron microscopy, a good interfacial bonding could be seen between quartz fibers and the resin matrix in Group D. In addition, it was found that Group D had low absorbability, low solubility and good biocompatibility. Conclusion It is shown that deposition of SiO₂ films on the quartz fiber by ALD can significantly enhance the mechanical properties of fiber-reinforced composites.

Objective To investigate the mechanism of vascular endothelial growth factor(VEGF) inducing tolerogenic dendritic cells(DCs) in oral squamous cell carcinoma (OSCC). Methods The DCs were divided into four groups: Control group (DC), VEGF group (VEGF added into DC), Co-culture group (DC co-cultured with SCC7) and Anti-VEGF group (anti-VEGF antibody added into DC co-cultured with SCC7). Flow cytometry (FCM) was used to detect DC surface markers. To detect the effect of DC on proliferation activity of T lymphocyte, the experiment included five groups: Nc group (T lymphocyte), Control group (T lymphocyte added into DC), VEGF group (T lymphocyte + DC + VEGF), Co-culture group (T lymphocyte + DC + supernatant of SCC7) and Anti-VEGF group (T lymphocyte + DC + supernatant of SCC7 + anti-VEGF antibody). Subsequently, the mixed lymphocyte reaction(MLR) was conducted. The expression levels of indole-2, 3-doxygenase(IDO)and programmed cell death 1 ligand 1(PD-L1)in DC were detected by western blot, real time PCR and FCM respectively. For the cytotoxic lymphocyte (CTL) assay, SCC7 cells and CTLs were mixed and CTL-mediated SCC7 cells cytotoxicity was tested. The experiment included four groups: Control group (T lymphocyte + DC), IDO inhibition group (T lymphocyte + DC + IDO inhibitor), Anti-PD-L1 antibody group (T lymphocyte + DC + anti-PD-L1 antibody) and Combination group (T lymphocyte + DC + IDO inhibitor + anti-PD-L1 antibody). The SCC7 tumor-bearing mice treated with IDO inhibitor and the anti-PD-L1 antibody were sacrificed and the tumor inhibition rate and the spleen index were determined. Results Compared with Control group, exogenous VEGF or SCC7 co-culture inhibited the relative number of DC expressing CD11C, CD80, CD86, CD40 and MHC Ⅱ. The positive DCs were increased in the Anti-VEGF group compared with VEGF or Co-culture group. In VEGF or Co-culture group, the number of T cells stimulated by SCC7-pulsed DCs was decreased compared with Control group. However, the ability of Anti-VEGF group to induce T cell proliferation was significantly increased compared with VEGF or Co-culture group. Significantly increased expression of IDO and PD-L1 were observed in VEGF and Co-culture group. However, this was partially reversed by addition of anti-VEGF antibody into the co-culture system. Compared with Control group, the expressions of CD11C and CD86 in DC in both the IDO inhibition group and Anti-PD-L1 antibody group were increased, and were significantly higher in the Combination group compared with the single drug groups. The similar results were exhibited in MLR and CTL assay. In vivo, the results revealed that the tumors obtained from the mice in three experimental groups were smaller than those in the control group. Furthermore, the tumor volume of the Combination group was the smallest. The spleen index of each group was calculated and the results showed the spleen index of the three experimental groups was significantly higher than that of Control group. Conclusion VEGF in OSCC micro-environment inhibits the maturation and function of DC that are transformed into tolerogenic DC by high expression of IDO and PD-L1.

Objective To prepare a composite membrane by chitosan/β-sodium glycerophosphate(CS/β-GP) thermosensitive hydrogel combined with stromal cell derived factor-1(SDF-1) and observe its biological characteristics in vitro. Methods Different doses of SDF-1 were added into CS/β-GP solution and then the thermosensitive gel time was measured. The SDF-1/CS/β-GP solution was membrane paved and dried to prepare composite membranes. The morphological characteristics were observed by scanning electron microscope(SEM). Composite membranes were placed into cell culture medium, and the supernatant(n=3) was extracted after standing at 6, 12, 24, 36, 48, 60 h, respectively. The concentration of SDF-1 in the solution was measured. Bone mesenchymal stem cells(BMSCs) were cultured in the Transwell room, and the composite membranes containing different concentrations of SDF-1 were placed in the lower chamber. There were four groups(n=3): Group M0 used CS/β-GP membrane(control group), Group M1, M2, M3 used SDF-1/CS/β-GP membrane(SDF-1 was 100, 200, 400 ng/mL respectively). After culture for 6, 12 and 24 h, the cells under the membrane were preserved and Giemsa stained and counted. The absorbance(OD) value was measured by MTT method to calculate the cell proliferation rate. SPSS 19.0 was used for multi-factor analysis of variance. Results After adding a certain amount of SDF-1 into CS/β-GP solution, the gel time did not change significantly(P>0.05). The SDF-1/CS/β-GP membrane was translucent and porous at 37 ℃. In this experiment, the volumic mass of SDF-1 released by SDF-1/CS/β-GP composite membrane increased gradually with the experimental time(P<0.01). Transwell cell chemotaxis test showed that the number of BMSCs cells with directional migration increased with the prolongation of observation time(P<0.01) and the increase of SDF-1 volumic mass(P<0.01). In MTT test, the OD value of migration cell solution increased with the prolongation of time(P<0.01) and the increase of SDF-1 volumic mass(P<0.01). Conclusion The SDF-1/CS/β-GP composite membrane has a porous structure and biological activity of chemotactic BMSCs directional migration. It is a potential membrane for guided tissue regeneration.

Objective To investigate the efficacy of different bleaching methods on white-spot lesions of the enamel using optical coherence tomography and to evaluate its feasibility for monitoring the therapeutic effects on white-spot lesions. Methods Forty-eight sound premolars extracted for orthodontic reasons were selected and cut for 4 mm×4 mm×2 mm enamel blocks in buccal surfaces of the crowns. The samples were covered with acid-resistant varnish (except for the buccal surfaces) and immersed in demineralization solution for 18 days to establish the white-spot lesion models of the enamels. Samples were randomly divided into four groups (n=12). Group A was given demineralization only. Specimens in Group B, C and D were treated with 40% hydrogen peroxide, resin infiltration and 40% hydrogen peroxide combined with resin infiltration, respectively. Eight samples in each group were randomly selected. OCT was applied to observe the optical changes of the enamel surface and according to the OCT scanning results, the demineralization depth of enamel samples in each group was calculated. Then, the enamel blocks were embedded in epoxy resins, except the buccal surfaces, and measured for the microhardness values of the enamel surface by a microindentation hardness tester. Four samples in each group were cut longitudinally, and the ultrastructural changes of enamel samples in each group were observed by scanning electron microscope. Results OCT showed that the light scattering characteristics of enamel surface changed in all groups, and the bright layer was formed, but the thickness of bright layer in Group C and D was significantly lower than that in Group A and B (P<0.05). The microhardness values (kg/mm²) of the samples in Group A-D were (214.99±31.70), (250.66±33.64), (312.42±18.01) and(286.53±26.65), respectively. The microhardness of enamel surfaces in Group C and D was significantly higher than that in Group A and B (P<0.05), and the ultrastructure of enamel surfaces in Group C and D were more flat and dense in SEM observation (P<0.05). Conclusion The methods of resin infiltration therapy or 40% hydrogen peroxide combined with resin infiltration could effectively improve white-spot lesions of the enamel and the non-invasive OCT can be used as a better evaluation method for the diagnosis and treatment of white-spot lesions of the enamel.

Objective To analyze and investigate the effects of implant location and axial direction on the stress distribution of implants, abutments, central screws, and crowns during immediate loading of maxillary mesial incisors with different alveolar fossa morphology based on three-dimensional finite element method. Methods Referring to the oral CBCT images of a healthy adult, a three-dimensional finite element model was established for immediate implant loading of maxillary central incisors with three alveolar fossa morphs: labial, intermediate, and palatal; different implant sites(apical site, palatal/labial site) and axes(tooth long axis, alveolar bone long axis) were simulated; the established model was loaded with a force of 100 N. ANSYS software was applied to analyze the stress values of the implants, abutments, central screwss, and crownss. Results The 3D finite element models of 12 maxillary central incisors with different alveolar sockets were successfully established;the implants and their superstructures were least stressed when the maxillary central incisors with partial labial and partial palatal shape were placed along the long axis of the alveolar bone in the palatal/labial position for immediate implant loading;the implants and their superstructures were least stressed when the maxillary central incisors with central shape were placed along the long axis of the tooth in the palatal position for immediate implant loading. The implant and its superstructure were subjected to the least stress when the implant was placed along the long axis of the tooth in the immediate loading position. Conclusion The bio-mechanical characteristics of the implant and its superstructure are influenced by the different socket morphology, implantation sites and axes. Therefore, in clinical practice, different implantation axes and implantation sites should be developed for different socket morphs.

Objective To analyze the condylar and inclination of the occlusal plane features in skeletal Class Ⅲ malocclusion patients with mandibular asymmetry by using cone beam computed tomography(CBCT). Methods Forty eligible patients with Angle Class Ⅲ malocclusion were enrolled. All individuals were classified based on the distance from Me point to median sagittal plane. The left and right angles between OP and FH plane, the position and morphology of the condyle were measured in both groups.Then the data collected were statistically analyzed. Results Compared to the opposite side, there was a statistically significant difference(P<0.05) in angle between OP and FH plane, the anterior joint space, superior joint space, lateral joint space and condylar mediolateral diameter, with a higher proportion of joint posteriority in deviated side. Mandibular deviations were positively correlated with both the anterior joint space of the deviated side and the angle between OP and FH plane of the opposite side(P<0.01). There was no statistical difference between the left and right side of angles between OP and FH plane, the position and morphology of the condyle in skeletal Class Ⅲ patients without mandibular deviation(P>0.05); the joint was predominantly in anterior and middle position. Conclusion There is asymmetry on the left and right sides of the inclination ofocclusal plane, the position and morphology of the condyle of skeletal Class Ⅲ malocclusion patients with mandibular asymmetry. Compared with the opposite side, the deviated side has smaller angle between OP and FH plane and smaller condylar mediolateral diameter, and the condyle shows generally more posterior, inferior and inward movement in glenoid fossa. The inclination of the occlusal plane and the position of condyle are significantly and positively correlated with the distance from Me point to median sagittal plane.

Objective To study the effect of a space stabilizing device on the capacity for osteogenesis in the bone-grafted area. Methods Patients with anterior teeth defects as well as labial alveolar ridge defects were randomly divided into two groups: the experimental group was treated using a space stabilization device after guided bone regeneration whereas the control group received regular guided bone regeneration. The CBCT data was analyzed prior to, immediately and 6 months after procedure to compare the osteogenesis with or without the device. Results Seventeen bone-grafted sites were examined(7 in the experimental group and 10 in the control group). At 2 mm and 4 mm below the alveolar ridge, the horizontal bone resorption rate in the experimental group was significantly lower than the corresponding level in the control group(P=0.001). The horizontal bone resorption rate at 2 mm below the alveolar ridge of each group was significantly higher than that at 4 mm below the alveolar ridge in corresponding groups(P=0.003). Conclusion The space stabilizing device used in this study has a positive clinical impact on preserving space stability and minimizing bone resorption.

Objective To investigate the efficacy of antibacterial peptides in the adjuvant therapy of stage Ⅲ periodontitis. Methods Fifty-one patients were randomly divided into simple mechanical curettage group, minocycline hydrochloride group and antibacterial peptide group according to the treatment mode. Three groups received periodontal sequential treatment, and after the ultrasonic supragingival scaling, they were performed with curettage, root surface planing, polishing and flushing. After treatment in the minocycline hydrochloride group and the biological antibacterial peptide group, minocycline hydrochloride ointment and biological antibacterial peptide periodontal gel were injected into the periodontal pocket respectively. The mechanical curettage group did not take medicine. Periodontal checklists at baseline and 90 d after treatment were recorded to compare differences of the three groups in periodontal probing depth (PD), bleeding index (BI) and attachment level (AL). Enzyme-linked immunosorbent assay (ELSIA) was used to detect the change of tumour necrosis factor-α (TNF-α), interleukin (IL)-1β by collecting the gingival crevicular fluid of the three sets at baseline, 7 d after treatment and 90 d after treatment. Results There was no statistically significant difference in periodontal clinical examination indexes(PD,BI,AL) and contents of TNF-α and IL-1β in the gingival crevicular fluid between the three groups at baseline (P>0.05). At 7 and 90 d after treatment, all indexes in the three groups were improved compared with those before treatment. The comparison between groups showed that in periodontal pockets with PD≤5 mm, there was no statistically significant difference in the indicators between the three groups. In periodontal pockets with PD≥6 mm, the minocycline hydrochloride group and the bio-antibacterial peptide group had no statistically significant difference in various indicators, but they were all better than the mechanical scaling group. Conclusion Basic periodontal therapy is an important treatment for stage Ⅲ periodontitis. Minocycline hydrochloride and biological antibacterial peptides are both effective adjuvant drugs for deep periodontal pockets with PD≥6 mm.

Objective To evaluate the effects of non-bracket invisible appliance mandibular advance(MA) on skeletal Class Ⅱ growing patients with mandibular retrusion. Methods Nineteen skeletal Class Ⅱ growing patients with mandibular retrusion who were treated in the department of stomatology of Changshu traditional Chinese medicine hospital from January 2018 to May 2021 were selected. They had an average age of (12.32±1.51) years old. The treatment group consisted of 10 children who were treated with MA. The control group consisted of 9 children who refused to treat their malocclusion. Cephalometrics of all patients were taken before and after the observation or treatment. The cephalometric data of two groups were analyzed. Results Compared with the control group, in the treatment gruop SNB angle, L1-NB angle, L1-NB distance, L6-MP distance, Z angle increased significantly (P<0.05);Co-Go distance, Co-Gn distance, SL increased more greatly than the control group; ANB angle, U1-SN angle, U1-NA angle, U1-NA distance, L1-MP distance, FCA angle decreased significantly (P<0.05); SE did not change significantly in the treatment group, but increased significantly in the control group (P<0.05). Conclusion MA can promote mandibular growth and improve lateral profile. The angle of the lower teeth and the angle of the mandible plane can be controlled by MA appliance.

An oral synechia is a fibrous or soft tissue adhesion between the maxilla and the mandible. These synechiae can appear at various locations in the oral cavity, with alveolar synechia being one of the manifestations. Alveolar synechia is a rare congenital deformity and often accompanied by additional congenital defects, such as cleft lip or palate, microglossia, micrognathia, or TMJ anomalies. Among these, cleft palate is the most common. A case of congenital alveolar synechiae with cleft palate is reported. The child is in good condition after surgical treatment. The etiology and treatment are discussed.

Laser therapy has become an important means of treating peri-implant diseases, and diode laser shows unique advantages in the adjuvant therapy of peri-implant diseases due to its excellent biological regulation, sterilization effect and biological safety. This article reviews the principle, characteristics, safety, biological effects of and clinical research on diode laser, in order to provide reference for its clinical application in the treatment of peri-implant diseases.

Dental caries, trauma, and iatrogenic stimulation can cause damage to the dentin-pulp complex. Preserving the viable pulp and promoting damage repair of the dentin-pulp complex is of great clinical significance at present. In recent years, studies have found that various small molecular compounds can regulate inflammation, promote the migration, proliferation, and differentiation of dental pulp stem cells, promote blood vessel, nerve regeneration and other biological processes by regulating key intracellular signaling pathways and metabolic pathways, and could thereby promote damage repair of the dentin-pulp complex. The objective of this paper is to review recent research on various small molecular compounds used in promoting the repair of dentin-pulp complex.

The ultimate treatment goal of periodontitis is the structural and functional regeneration of periodontium. However, existing methods for periodontal regeneration have difficulties in regenerating the hierarchical structure. Therefore, stem cell-based tissue engineering has attracted more and more attention for its advantages of self-renewal and multi-lineage differentiation potential. This review summarized the progress of research on periodontal tissue regeneration by combined biomaterials of dental-derived stem cells. It is pointed out that the application of autologous stem cell transplantation is limited by the donor source, and the subsequent research should focus on the development of multi-phase scaffold materials and the attempt to establish a stem cell bank.

Periodontitis is one of the most common oral diseases in humans. As the initiating factor of periodontitis, dental plaque bacteria, is the primary factor leading to periodontitis. Quorum-sensing system relies on quorum-sensing signaling molecules to regulate and strengthenthe communication between different kinds of bacteria, strengthen the communication between bacteria, and promote the occurrence and development of diseases. Quorum-sensing system also plays an important role in promoting the formation of dental plaque biofilm by dental plaque bacteria. In recent years, many studies have shown that quorum-sensing inhibitors can effectively attenuate quorum sensing between bacteria and inhibit and reduce the formation of plaque biofilms between bacteria and the expression of their virulence factors. In this paper, we will review the progress of research on the effects of quorum-sensing signaling molecules on periodontitis pathogens.

In recent years, more and more attention has been paid to the correlation between periodontitis and prostatic diseases. Aging, obesity, smoking and psychological factors are common risk factors of these two diseases, but the key correlation mechanism is not clear. This article reviews the research on and possible biological mechanism of chronic periodontitis and prostatic diseases, in order to provide basis for disease management and clinical research in the future.

In recent years, clear aligner technology has been maturing and is rapidly gaining popularity in the orthodontic market for its aesthetic and removable properties. However, despite the background of its large-scale clinical application, mechanical properties of clear aligners need to be studied in depth. This paper reviews the factors influencing mechanical properties of clear aligners and the current status of research to provide evidence-based guidance for clinical application.

With the development of molecular biology, biomaterials and tissue engineering, regenerative treatment of pulpal and periradicular diseases is facing new opportunities. At present, a large number of studies on dental pulp regeneration reveal that cytokines are essential for promoting migration, proliferation and osteogenic differentiation of dental pulp stem cells. In this paper, we review several kinds of cytokines related to dental pulp regeneration, and analyze their roles and regulatory mechanisms in dental pulp regeneration.