Periodontitis is a critical risk factor for the occurrence and development of diabetes.Porphyromonas gingivalis may participate in insulin resistance(IR)caused by periodontal inflammation,but the functional role and specific mechanisms of P.gingivalis in IR remain unclear.In the present study,clinical samples were analysed to determine the statistical correlation between P.gingivalis and IR occurrence.Through culturing of hepatocytes,myocytes,and adipocytes,and feeding mice P.gingivalis orally,the functional correlation between P.gingivalis and IR occurrence was further studied both in vitro and in vivo.Clinical data suggested that the amount of P.gingivalis isolated was correlated with the Homeostatic Model Assessment for IR score.In vitro studies suggested that coculture with P.gingivalis decreased glucose uptake and insulin receptor(INSR)protein expression in hepatocytes,myocytes,and adipocytes.Mice fed P.gingivalis tended to undergo IR.P.gingivalis was detectable in the liver,skeletal muscle,and adipose tissue of experimental mice.The distribution sites of gingipain coincided with the downregulation of INSR.Gingipain proteolysed the functional insulin-binding region of INSR.Coculture with P.gingivalis significantly decreased the INSR-insulin binding ability.Knocking out gingipain from P.gingivalis alleviated the negative effects of P.gingivalis on IR in vivo.Taken together,these findings indicate that distantly migrated P.gingivalis may directly proteolytically degrade INSR through gingipain,thereby leading to IR.The results provide a new strategy for preventing diabetes by targeting periodontal pathogens and provide new ideas for exploring novel mechanisms by which periodontal inflammation affects the systemic metabolic state.

Objective : To investigate the effects of N-cadherin silencing on the proliferation and migration of human dental pulp stem cells (DPSCs) and to provide experimental evidence for DPSCs-based dental pulp regeneration. Methods: DPSCs were transfected with N-cadherin shRNA lentivirus, and the knockdown efficiency of N-cadherin at both the mRNA and protein levels was confirmed by qRT-PCR and Western blot. The experiment included a negative control group (shRNA -NC) and an N-cadherin shRNA silencing group. Cell proliferation was detected by the CCK-8 method. Cell cycle and apoptosis were assessed by flow cytometry, and cell migration was detected using the Transwell method. Results: N-cadherin shRNA significantly reduced the expression levels of N-cadherin mRNA and protein in DPSCs (P<0.001). The proliferation activity of the N-cadherin shRNA group was significantly greater than that of the shRNA-NC group on the 3rd and 4th days after cell inoculation and lower than that of the shRNA-NC group from the 6th to 8th days (P<0.05). On the 3rd day after cell inoculation, the proportion of cells in S phase and G2 phase in the N-cadherin shRNA group was greater than that in the shRNA-NC group (P<0.05). On the 6th day after cell inoculation, the proportion of cells in S phase and G2 phase in the N-cadherin shRNA group was lower than that in the shRNA-NC group (P<0.05), and the proportion of apoptotic cells in the N-cadherin shRNA group was greater than that in the shRNA-NC group (P<0.01). Low densities cells and high densities cells were inoculated into Transwell upper chamber for 20 h, the number of cells passing through the membrane pores of upper chamber in the N-cadherin shRNA group was greater than that in the shRNA-NC group (P<0.001). Conclusion Silencing N-cadherin expression can promote the early proliferation and migration of DPSCs.

Vital pulp therapy aims to maintain healthy pulp tissue as much as possible to improve the long-term survival of teeth. It has limited indications and uncertain curative effects. The pathological changes in inflamed pulp are the histological basis for the determination of treatment strategies and the treatment outcome; however, pulp sensitivity testing cannot reflect the actual histological status of the pulp. With the development of basic and clinical research on vital pulp therapy, the innovation of modern diagnostic and therapeutic technology and capping material, vital pulp therapy can be used as a treatment of teeth on which it was previously thought pulpectomy was necessary. Based on the evidence-based literature, this paper analyzes and summarizes the pathological changes of pulpitis and clinical research on the treatment of pulpitis. Vital pulp therapy can be a treatment for mature teeth with carious exposure and symptoms of irreversible pulpitis if comprehensive applications, including laser Doppler flowmetry, tissue oxygen monitoring, magnetic resonance imaging and microscopy, are used to determine the degree of pulp retention and if infection control and the use of biocompatible capping material are emphasized. In the future, it will be necessary to improve the success rate of vital pulp therapy for the treatment of pulpitis through research on the mechanism of pulp repair and regeneration, the precise diagnosis of pulpitis, and the development of pulp capping materials.

Objective: To observe the permeability of four kinds of self-etching adhesives in aged glass-fiber-reinforced composite (GFRC). Methods: After light polymerization following the manufacturers’ instructions, a total of 80 pieces of bisphenol-A-glycodal-methacrylate (Bis-GMA)+ polymethyl methacrylate (PMMA) based GFRC were randomly divided into two main groups: test group and control group, each group was then divided into four subgroups with 10 samples for each subgroup. While the test group was conducted to be aged through thermocycling at 5 ℃/55 ℃, the control group remained fresh. After the addition of a fluorescent dye (rhodamine-B-isothiocyanate), four self-etching adhesives AdperEasy One (AEO), S 3 BOND (S 3B), Tetric N-Bond Self-Etch (TNB), G-Bond (GB) were correspondently applied to the test and control groups and were light polymerized. Specimens were sectioned using hard tissue cutting and grinding system. Slices from each subgroup were observed under a confocal laser scanning microscope, the depth of dye permeation (DDP) under the surface of GFRC in each group was measured and the Results were statistically analyzed. Results: The DDP of AEO was the deepest (32.58 ± 6.06) μm, and that of TNB was the shallowest (6.19 ± 1.38)μm among the four self-etching adhesive subgroups in the control group. The order of each group was AEO > GB > S 3B > TNB. The DDP of the four subgroups in the test group was significantly shallower than that in the control group (P < 0.05). The change in GB was the greatest (9.05 ± 2.35)μm/(28.93 ± 5.32)μm. In the test group, the DDP in AEO was the deepest (28.42 ± 5.32)μm, and the DDP in TNB was shallowest (1.93 ± 0.22)μm again. The order of each group was AEO > S 3B > GB > TNB. In the test group, while the layer of fluorescent dye of AEO and S 3 B could still be seen distinctly, that of TNB and GB was hard to recognize. The DDP of AEO was the deepest (32.58 ± 6.06) μm, and that of TNB was the shallowest (6.19 ± 1.38)μm among the four self-etching adhesive subgroups in the control group. The order of each group was AEO > GB > S 3B > TNB. The DDP of the four subgroups in the test group was significantly shallower than that in the control group (P < 0.05). The change in GB was the greatest (9.05 ± 2.35)μm/(28.93 ± 5.32)μm. In the test group, the DDP in AEO was the deepest (28.42 ± 5.32)μm, and the DDP in TNB was shallowest (1.93 ± 0.22)μm again. The order of each group was AEO > S 3B > GB > TNB. In the test group, while the layer of fluorescent dye of AEO and S 3 B could still be seen distinctly, that of TNB and GB was hard to recognize. The self-etching adhesives of AEO and S 3 B still have good permeation effect in this kind of aged GFRC, which can help to establish a good bond between these aged GFRC and the subsequent repair of composite resin.

OBJECTIVE: To explore the histological structure of the deciduous teeth and the tooth germs of Tibetan miniature pigs for studies of dental tissue diseases and tooth regeneration. METHODS: The structure of the deciduous teeth of Tibetan miniature pigs was observed by X-ray. The ultrastructure of the enamel and dentin of deciduous teeth was characterized by scanning electron microscopy. The jaws and teeth were three-dimensionally reconstructed using Mimics software based on Micro-CT scanning of the deciduous teeth. Image J software was used to calculate the gray value and the mineralization density of the deciduous teeth. Hisotological structure of the tooth germ and the pulp tissue of Tibetan miniature pigs was observed using HE staining. RESULTS: The deciduous teeth of Tibetan miniature pigs were composed of enamel, dentin and medullary pulp tissue. The permanent tooth germ were formed during the deciduous dentition. The enamel and dentin ultrastructure of deciduous teeth were consistent with that of human deciduous teeth. The enamel and dentin mineralization densities were 2.47±0.09 g/cm and 1.72±0.07 g/cm, respectively. The pathological structures of tooth germ and pulp tissue were similar to those of human teeth, and the pulp tissue of the deciduous teeth was in an undifferentiated state. CONCLUSIONS The deciduous teeth of Tibetan miniature pig have similar anatomy, ultrastructure and histopathological structure to human teeth and can serve as a good animal model for studying human dental tissue diseases and the mechanisms of tooth regeneration.
Animals ; Dental Enamel ; ultrastructure ; Dental Pulp ; Dentin ; ultrastructure ; Swine ; Swine, Miniature ; Tibet ; Tooth Germ ; Tooth, Deciduous ; anatomy & histology

Objective: To observe the stress distribution according to a model of the bucco-occluso-lingual (BOL) inlay of mandibular first molar after restoration to provide a basis for the clinical treatment of cracked tooth with BOL inlay. Methods: A three-dimensional finite element model of mandibular first molar was established by combining micro-CT scanning technology with Mimics, UG, Ansys and Midas-FEA software. Based on this model, a BOL inlay restoration model was established. The material parameter of inlay IPS e.max CAD was given, and a Von-mises stress distribution nephogram under the same loading condition was obtained. The results of the stress distribution in each model were compared. Results : The stress of intact teeth is mainly concentrated in the central fissure of the occlusal surface at the crown. The stress of the cavity after BOL inlay restoration is mainly concentrated in the mesial and distal walls of the cavity, the axial-pulpal line angle and the gingival wall. The stress of the inlay is mainly distributed at the bottom of the inlay, axial wall and the gingival wall. Conclusion BOL inlay restoration change the stress distribution in the complete dental model, which relieves the stress concentration in the fossa and groove of the occlusal surface and can play an active role in the treatment of cracked tooth.

Objective: To explore methods using modified tissue enzymatic separations for culturing primary hDPSCs in vitro and further identify the cells produced. Methods : Primary hDPSCs were cultured using the modified tissue enzymatic separation method, and cells were identified by morphology, cell surface markers, and differentiation potential and evaluated using flow cytometry and growth curves. Results : The hDPSCs were successfully isolated using the modified tissue enzymatic separation method. The morphology of these cells was similar to that of fibroblasts and mesenchymal stem cells, and the growth curve was "S" -type. The results of cell phenotype analysis indicated that the cells were positive for surface markers of mesenchymal stem cells, including CD29, CD44, and CD90, and negative for markers of hematopoietic stem cells, including CD34, CD45, and CD106. The cells were capable of differentiating into multiple cell types. Conclusion The modified tissue enzymatic separation method can successful be used to culture primary hDPSCs in vitro.

Tooth development is a complex process that involves precise and time-dependent orchestration of multiple genetic, molecular, and cellular interactions. Ameloblastin (AMBN, also named "amelin" or "sheathlin") is the second most abundant enamel matrix protein known to have a key role in amelogenesis. Amelogenesis imperfecta (AI [MIM: 104500]) refers to a genetically and phenotypically heterogeneous group of conditions characterized by inherited developmental enamel defects. The hereditary dentin disorders comprise a variety of autosomal-dominant genetic symptoms characterized by abnormal dentin structure affecting either the primary or both the primary and secondary teeth. The vital role of Ambn in amelogenesis has been confirmed experimentally using mouse models. Only two cases have been reported of mutations of AMBN associated with non-syndromic human AI. However, no AMBN missense mutations have been reported to be associated with both human AI and dentin disorders. We recruited one kindred with autosomal-dominant amelogenesis imperfecta (ADAI) and dentinogenesis imperfecta/dysplasia characterized by generalized severe enamel and dentin defects. Whole exome sequencing of the proband identified a novel heterozygous C-T point mutation at nucleotide position 1069 of the AMBN gene, causing a Pro to Ser mutation at the conserved amino acid position 357 of the protein. Exfoliated third molar teeth from the affected family members were found to have enamel and dentin of lower mineral density than control teeth, with thinner and easily fractured enamel, short and thick roots, and pulp obliteration. This study demonstrates, for the first time, that an AMBN missense mutation causes non-syndromic human AI and dentin disorders.
Adult ; Amelogenesis Imperfecta ; genetics ; Cells, Cultured ; China ; Codon ; Dentin ; abnormalities ; ultrastructure ; Female ; Humans ; Male ; Microsatellite Repeats ; Microscopy, Electron, Scanning ; Middle Aged ; Mutation, Missense ; Pedigree ; RNA ; analysis ; Transfection ; Whole Exome Sequencing

Objective : To investigate the short-term clinical effect of semiconductor laser exposure combined with total glucosides of paeony (TGP) capsules for the treatment of erosive oral lichen planus (OLP). Methods: Sixty-four patients with erosive oral lichen planus were randomly divided into two groups: the experimental group and the control group. Patients in the control group were treated with TGP capsules, while patients in the experimental group were treated with TGP capsules and semiconductor laser irradiation. The clinical effects were evaluated 3 months after treatment. The data were analyzed using the SPSS 17.0 software package. Results : Three months after treatment, the effective rate in the experimental group was 90.6%, which was significantly higher than that in the control group (59.4%, χ 2=5.62, P < 0.05). The physical condition and visual analogue scale (VAS) scores in the experimental group were 2.17 ± 1.49 and 1.25 ± 1.29, respectively. The physical condition and VAS scores in the control group were 3.55 ± 1.41 and 2.09 ± 1.24, respectively. The physical condition and VAS scores in both groups were significantly higher after treatment than before (P < 0.05). Three months after treatment, the physical condition score (t=3.805) and VAS score (t=2.655) in the experimental group were significant higher than those in the control group (P < 0.05). Conclusion Semiconductor laser irradiation combined with TGP capsules can improve the short-term clinical efficacy in the treatment of erosive OLP.

Tooth defects due to dental caries, trauma, abrasion, etc., are extremely common and can be treated by direct or indirect restoration. Compared with resin directly filling the body, an inlay can better restore the occlusal contact relationship and the adjacent surface contact relationship and has good mechanical properties. In recent years, with the development of ceramic materials and bonding systems and the popularity of chairside CAD/CAM technology, the chairside CAD/CAM porcelain inlay restoration program has been well received by doctors and patients because of its accuracy, convenience, aesthetics, hardness and stability, and this program is widely used clinically. This review covers the research status of various aspects such as indications and contraindications for chairside CAD/CAM inlay restoration, pre-restoration preparation, tooth preparation, hole type, impression taking and design, porcelain block selection, bonding, polishing, postoperative doctor’s instructions, and common postoperative complications. It is expected to provide a reference for the clinical application of and research on chairside CAD/CAM inlay restoration technology.