Objective： To study the effect of sodium ferulate on periodontal tissue microcirculation of periodontitis with diabetes in rats. Methods： A self-constructed rat model of periodontitis with diabetes was used to detect gingival bleeding index, degrees of the loosening and alveolar bone resorption after intervention with sodium ferulate for 1 month, 3 months and vascular endothelial growth factor (VEGF) inhibitor (as positive control). The pathological condition of rat periodontal tissue was detected by HE staining. The vascular permeability of the gingiva was detected by vascular permeability staining； The expression of VEGF and CD34 in the periodontal tissues of each group was detected by immunohistochemistry, then the microvessel density (MVD) was calculated. Results： The gingival bleeding index and loose degrees were significantly reduced after the intervention of sodium ferulate, and the degree of alveolar bone loss was improved, whose effect was more obviously over time with the intervention. HE staining results showed that after the intervention of sodium ferulate, the inflammatory cells in the gingival tissues were significantly reduced, and the periodontal ligaments were arranged neatly, even osteoblasts were observed. The results of vascular permeability staining showed that the vascular permeability of the gingiva was significantly reduced after the intervention of sodium ferulate compared with the non-intervention group. The results of immunohistochemistry showed that the MVD count was significantly decreased after sodium ferulate intervention, and the VEGF positive cells were significantly reduced and the staining was weakened in the rats’ gingiva. The effect of VEGF inhibitor is the same as the results of intervention of sodium ferulate after 3 months. Conclusions： Sodium ferulate can improve the periodontal tissue microcirculation of periodontitis with diabetes by inhibiting the expression of VEGF in periodontal tissues.

Objective： To investigate the effect of local periodontitis on orthodontic tooth movement in a mouse model. Methods: 12-week-old C57 mice were enrolled, and injected with lipopolysaccharide (LPS) via the gingiva lateral to the maxillary molar region to establish a model of periodontitis. Mice injected with the same volume of saline were included into the control group. Alveolar bone loss was scanned and quantitatively analyzed using Micro-CT. A mouse model of orthodontic tooth movement was established during the stationary phase of periodontitis. The density of maxillary bone and the distance of tooth movement were scanned and quantitatively analyzed using Micro-CT with the force value set at 30 g at a duration of 7 days. Results：The orthodontic tooth movement during the stationary phase of LPS-induced periodontitis demonstrated a slight decrease in the bone mineral density of maxillary bone (P < 0.05), and a remarkable increase in the distance of tooth movement (P < 0.05) when compared to that after saline injection. Conclusions: Local periodontitiscan facilitate orthodontic tooth movement in mice. Our findings will provide references for the effect and risk assessment of tooth movement in the combined therapy of periodontics and orthodontics in clinical practice, and provide guidance for the optimization of orthodontic tooth movement.

Objective:This study aimed to evaluate the effect of the thickness and tooth preparation on fracture strength and failure mode of full-contour zirconia occlusal veneer. Methods：Standard artificial molars of 3 different groups(n=72) were prepared:Group A: the occlusal surface was ground of evenly by 0.5 mm; Group B: the occlusal surface was ground of evenly by 0.5 mm, and the axial surface was parceled for 1.5 mm; Group C: the occlusal surface was ground of evenly by 0.5 mm, and cavity fixation was prepared. Three different models of full contour zirconia occlusal veneers were designed with different thickness of 0.5 mm, 1.0 mm, and 1.5 mm respectively using CAD/CAM system and Dental Designer software. Fracture strength and failure mode of zirconia occlusal veneers were measured and recorded. Results：The average fracture strength value of full-contour zirconia occlusal veneer with different thicknesses and different preparation were: Group A:（1275.9±205.6）N（0.5 mm）,（2320.6±296.7）N（1.0 mm）,（4909.1±399.3）N（1.5 mm）；Group B:（1404.5±215.3）N（0.5 mm）,（2509.8±380.6）N（1.0 mm）,（4917.8±320.4）N（1.5 mm）；Group C:（1279.6±248.4）N（0.5 mm）,（2346.6±260.2）N（1.0 mm）,（4575.3±458.7）N（1.5 mm）. Fracture strength of full-contour zirconia occlusal veneers increased in parallel with the increase of their thickness. Fracture strength of occlusal veneers with different thickness and preparation was significantly different, while that of occlusal veneers with the same thickness but different preparation showed no significant difference. The failure mode of 0.5 mm group was similar to that of 1.0 mm group but different from that of 1.5 mm group. Conclusions：Thickness is a positive correlation factor for the fracture strength of full-contour zirconia occlusal veneers. Preparation has no effect on the fracture strength of occlusal veneers. 0.5 mm is an acceptable thickness for zirconia occlusal veneers in clinical practice.

Objective： To investigate the effect of dopamine and dopamine/Type I collagen on the adhesion behavior of MC3T3-E1 cells. Methods： To evaluate the cell adhsion, the surface dopamine-coated (DOPA) and dopamine/collagen surface-coated (DOPA+Col) were prepared respectively. The surface without coating was set as control. MC3T3-E1 cells were chosen to seed onto the three groups (DOPA, DOPA+Col, Control), respectively. CCK-8 were used to evaluate the cell proliferation. The adhesion of MC3T3-E1 cells were observed by field emission scanning electron microscope (FESEM), confocal laser scanning microscope (CLSM) and stereo microscope. Results： There was no difference in cell proliferation at 1 d, 3 d or 7 d (P > 0.05) in each group. For adhesion morphology, MC3T3-E1 extended and adhered more on the DOPA and DOPA+Col treated surfaces. Conclusions： It revealed that dopamine or dopamine + Type I collagen were favorable for cell adhesion. Both treatments have good application prospects in bone tissue engineering.

Objective：To explore the application of computer-aided dynamic navigation system in zygomatic implantation. Methods：A 48-year-old male with severely atrophicmaxilla was selected and then two bilateral zygomatic implants were implanted with computer-aided dynamic navigation system according to the angulation of anterior teeth. The final restoration was completed six months after the implantation.Results：The patient achieved good therapeutic effect and his masticatory function recovered well. After three years of observation, no obvious bone resorption was found in both implants, and the patient was satisfied with the therapeutic effect. Conclusions：Computer-aided dynamic navigation system enjoys bright application prospects since it can effectively avoid the risk of zygomatic implant.

Objective： To compare the clinical and radiographic outcomes of pulp revascularization and apexification on immature permanent necrotic teeth with apical periodontitis. Methods： Clinical and radiographic data were collected from 26 immature permanent teeth with apical periodontitis at Affiliated Stomatology Hospital of Nanjing Medical University(follow-up time lasted up to 6 months). Teeth treated with pulp revascularization were in the experimental group while those treated with apexification were in the control group(13 cases per group). Clinical success rate was evaluated. The increase of root length, radiographic root area(RRA) and apical diameter of the revascularized teeth and the apexificated teeth were measured and compared according to the periapical radiographs. Results： At the end of 3 months’ follow-up, the experimental group showed a significant change in apical diameter and radiographic root area compared with the control group（P<0.05).There was no significant difference in the root canal length between the two groups. At the end of 6 months’ follow-up, the experimental group showed a significant change in radiographic root area compared with the control group（P<0.05).There was no significant difference in the root canal length and apical diameter between the two groups. Conclusions： Pulp revascularization in immature permanent necrotic teeth with apical periodontitis showed a better outcome than apexification.

Objective: To evaluate the clinical efficacy of variation design of the upper margin of cingulum in all-ceramic crown restoration for upper anterior teeth in deep over-bite patients. Methods: 60 anterior teeth from 36 deep overbite patients were restored with zirconia all-ceramic restorations (upper margin of lingual cingulum). The restorations were evaluated 6 months later according to the Modified USPHS Criteria. Results: 96.67% of 60 restorations were scored A in indices like crown integrity , margin sealing, margin coloring,color, shape, secondary caries, and gingival 6 months later. Conclusions: The variation design of the upper margin of cingulum provides clinically effective method in all-ceramic crown restoration for upper anterior teeth in deep overbite patients.

Objective： To compare the short-term effects of Nd:YAG laser and fluor protector in the treatment of dentin hypersensitivity after periodontal initial therapy. Methods：42 cases of chronic periodontitis patients with dentin hypersensitivity after periodontal initial therapy (scaling and root planing, SRP), were randomly divided into two groups. Laser group (60 teeth): treated with Nd:YAG laser; Fluor protector group (60 teeth): fluor protector smeared. The degree of pain was recorded before and after treatment immediately, 1 week and 1 month later. Total effective rate was calculated to evaluate short-term clinical effect. Results： Immediately after treatment, the total effective rates of laser group and fluor protector group were respectively 95% and 93.33% (P＞0.05). One week later, the total effective rates of two groups were 91.67% and 90% (P＞0.05). A month after therapy, the total effective rate of laser group was 88.33%, whereas the total effective rate of fluor protector group was 78.33% (P＜0.05). Conclusions： There is no difference in treating dentin hyper sensitivity after SRP between Nd: YAG laser and fluor protector group within 1 week, but laser irradiation is superior in 1 month post-operative observation.

Objective： To compare the effect of high speed turbine method and traditional bone chisel method in mandibular impacted third molar extraction. Methods： Eighty patients with bilaterally symmetrical middle and low mesioangular impaction mandibular third molars were randomly divided into high-speed turbine method and traditional bone chisel method. The operative time were recorded. The patients were followed up for 2 and 5 days after operation. The postoperative complications such as swelling, pain, limitation of mouth opening, dry socket, numbness of lower lip were recorded. Results： The average operation time of the high speed turbine group was (12.40±3.85)min, which was significantly lower than that of the traditional method group by (17.27±4.47) min (P＜0.05). High speed turbine group was also superior to the traditional bone chisel method group in postoperative pain, swelling and limitation of mouth opening (P＜0.05). There was no statistical significance between the two groups in postoperative bleeding, dry socket and the lower lip numbness (P＞0.05). Conclusions： High-speed turbine method has the advantages of less trauma, shorter operative time and less complications.

Caries is a chronic progressive disease, dental plaque biofilm is the microenvironment in which caries occur, and is the initiating factor of caries.Streptococcus mutans is currently recognized as the main cariogenic bacteria, and the search for effective methods against the biofilm of mutans has become a hot topic.This paper reviews the methods of removing Streptococcus mutans biofilm from the three layers of physics, chemistry and biology, aiming to provide new ideas and means for the prevention and treatment of caries.