[Detection of anaerobes and drug sensitivity from the periodontal pockets of patients with combined periodontal-endodontic lesions].

PURPOSE: To investigate the correlation between the composition of bacterial flora isolated from deep periodontal pockets with combined periodontal-endodontic lesions, and to test the antibiotic susceptibility of anaerobes. METHODS: Microbial samples were taken from 82 deep periodontal pockets with combined periodontal-endodontic lesions using adequate techniques, and divided into two groups: endo-perio group and perio-endo group. Antibiotic susceptibility of cultivable anaerobes were tested with agar dilution method. RESULTS: Eighty-six cultivable anaerobes were isolated, including Streptococcus spp, Prevotella spp, Actinomycetes spp, Veillonella spp, Fusobacterium spp and etc. 53.4% were gram-positive anaerobes, while 46.51% were gram-negative anaerobes. The detection rate of anaerobes in endo-perio group and that in perio-endo group had significant difference. Most isolated anaerobes were sensitive to six drugs. The resistance rates of penicillin, clindamycin, metronidazole were 6.8%, 13.9% and 2.2%. CONCLUSIONS: There is a close relationship between anaerobes and combined periodontal-endodontic lesions. Drug sensitive susceptibility should be detected prior to clinical treatment of combined periodontal-endodontic lesions.

[Clinical effect of pit and fissure sealant used in combination with different etching adhesive and 3M-Z350 flowable resin on young permanent teeth].

PURPOSE: To compare the effect of different etching adhesive and flowable resin in deep pits and fissures of young permanent molars sealant technique. METHODS: Children aged 6-8 years old were included in the study. The split mouth design was used. The first permanent molars were randomly assigned into 2 experimental groups:A and B.The teeth in group A were sealed with flowable resin and self-etching adhesive,while the teeth in group B were sealed with flowable resin and phosphate acid system. The children were followed up every year, and the sealants were observed and evaluated. SPSS13.0 software package was used for statistical analysis. RESULTS: After 1 year, 2 and 3 years,the retention rate of group A was significantly lower than that of group B(P<0.05),while group A had more caries than group B(P<0.05) except at 1-year. CONCLUSION: Self-etching adhesive and flowable resin doesn't have excellent clinical effect on caries prevention.

Genipin-cross-linked collagen/chitosan biomimetic scaffolds for articular cartilage tissue engineering applications.

In this study, genipin-cross-linked collagen/chitosan biodegradable porous scaffolds were prepared for articular cartilage regeneration. The influence of chitosan amount and genipin concentration on the scaffolds physicochemical properties was evaluated. The morphologies of the scaffolds were characterized by scanning electron microscope (SEM) and cross-linking degree was investigated by ninhydrin assay. Additionally, the mechanical properties of the scaffolds were assessed under dynamic compression. To study the swelling ratio and the biostability of the collagen/chitosan scaffold, in vitro tests were also carried out by immersion of the scaffolds in PBS solution or digestion in collagenase, respectively. The results showed that the morphologies of the scaffolds underwent a fiber-like to a sheet-like structural transition by increasing chitosan amount. Genipin cross-linking remarkably changed the morphologies and pore sizes of the scaffolds when chitosan amount was less than 25%. Either by increasing the chitosan ratio or performing cross-linking treatment, the swelling ratio of the scaffolds can be tailored. The ninhydrin assay demonstrated that the addition of chitosan could obviously increase the cross-linking efficiency. The degradation studies indicated that genipin cross-linking can effectively enhance the biostability of the scaffolds. The biocompatibility of the scaffolds was evaluated by culturing rabbit chondrocytes in vitro. This study demonstrated that a good viability of the chondrocytes seeded on the scaffold was achieved. The SEM analysis has revealed that the chondrocytes adhered well to the surface of the scaffolds and contacted each other. These results suggest that the genipin-cross-linked collagen/chitosan matrix may be a promising formulation for articular cartilage scaffolding.

[A preliminary analysis of the ratio between the upper and lower anterior teeth].

PURPOSE: The widths of anterior teeth are measured and compared to see if there was any specific ratio between the anterior teeth, and to provide some referential data for clinical application in esthetic dentistry. METHODS: Gypsum casts of the maxillary and mandibular arches were made by traditional ways. With the help of dividers and vernier calipers, the widths of anterior teeth were measured. The mean values were gained by doing the measurement several times. SAS6.12 software package was used for grouped t test, paired t test and REG regression. RESULTS: Statistically significant difference(P<0.01) was observed, when comparing the widths of anterior teeth with their ideal golden section(0.618 or 1.618). There were statistically significant differences in the correlation coefficient of anterior teeth(P=0.0001). CONCLUSIONS: The golden section is not found in the anterior teeth. There is some proportional relationships between the upper and lower anterior teeth.

[Clinical evaluation of fluor protector and glass-ionomer cement used as pit and fissure sealant for preventing pit and fissure caries in children].

PURPOSE: To study the clinical effect of the fluor protector and glass-ionomer cement used as pit and fissure sealant for preventing pit and fissure caries in children. METHODS: 622 health permanent teeth in 6-8 years old children were divided into three groups. Children in the experimental group A (n=207,335 teeth) underwent fluor protector every six months, experimental group B(n=205, 327 teeth) with glass-ionomer cement used as pit and fissure sealant and children in the control group(n=210, 354 teeth) underwent no treatment. The incidence of caries were compared among the three groups using SPSS10.0 software package after 3 years. RESULTS: After 3 years, the incidence of caries in A and B experimental groups were lower than in the control group, the difference was significant (P<0.01), but there were no significant difference between group A and group B (P>0.05). CONCLUSION: Fluor protector and glass-ionomer cement used as pit and fissure sealant also have good clinical effect in preventing caries.

[Clinical evaluation of two light cured pit and fissure sealants for preventing pit and fissure caries in children].

PURPOSE: To evaluate the clinical effect of two light cured pit and fissure sealants for preventing pit and fissure caries. METHODS: 416 health permanent teeth in 162 children aged 6 to 8 years old children were divided into two groups, enameloplasty sealant technique (EST) and cup-shaped brush sealant technique (CST) were used in two groups, respeitively. 90 and 112 contralateral healthy teeth were used as self controls respectively. The rate of the sealant reservation and the incidence of caries were compared in the two groups, and the clinical effect of the two groups was compared using SPSS10.0 software package for Chi-square test. RESULTS: After 3 years, the rate of the sealant reservation and the incidence of caries of EST were 85.4% and 0.9% respectively, the rate of the sealant reservation and the incidence of caries of CST were 63.8% and 6.7% respectively. Statistical analysis revealed a significant difference (P<0.05) between the two groups. CONCLUSION: EST and CST both have good clinical effects, While EST is superior to CST in preventing pit and fissure caries.

[Primary culture and identification of mouse odontoblast-like cells].

PURPOSE: To culture primary mouse odontoblast and to provide a base for study on inducing ES cells to odontoblast. METHODS: Lower incisor germs were removed from 1-week-old mouse. The dental papillae were isolated in microscope, and the dental papillae cells were dispersed using 0.25% collagenase and 0.25% trypsin. The cell clones, which had similar morphology to odontoblasts, were selected for further culturing. The primary cultured cells were identified by light and electron microscopes and mRNA expression of mouse dentin sialophoprotein. RESULTS: The cultured cells had the same morphology and ultrastructure. They were rich in Golgi's complex, ribosome and rough endoplasmic reticulum. These cells expressed DSPP at mRNA levels. CONCLUSION: The cultured cells were mouse odontoblast-like cells. The method could be used for the study of odontal cells in vitro.

[A three-year clinical evaluation of ceramic optimized polymer posterior inlays].

PURPOSE: To evaluate the clinical results of ceramic optimized polymer (Targis) posterior inlays. METHODS: 345 type I cavities were divided into two groups: 170 in Targis inlays group (42 premolars and 128 molars) and 175 in control group (composite resin inlays, 45 premolars and 130 molars). The clinical effects of Targis inlays and composite resin inlays in posterior teeth were compared in marginal discoloration, marginal adaption, secondary caries, anatomic shape integrity, fractures of tooth and color match 3 years later. The data were analyzed using Chi-square test. RESULTS: 3 years after treatment, 166 Targis inlays were followed up, 2 had marginal discoloration, 158 had good marginal adaption, 162 had anatomic shape integrity, 1 had secondary caries, 161 had color match, and 5 had fractures of teeth. 169 composite resin inlays were followed up, 27 had marginal discoloration, 134 had good marginal adaption, 150 had anatomic shape integrity, 20 had secondary caries, 164 had color match,5 had fractures of teeth. The marginal discoloration, marginal adaption, secondary caries, anatomic shape integrity of Targis inlays were better than that of composite resin inlays (P < 0.05), but fractures of teeth was not different between inlays in the two group (P > 0.05). CONCLUSION: Targis posterior inlays is a good newly developed prosthesis.

[Induction of mouse embryonic stem cells forming odontoblast-like cells by co-culture with pulp fibroblast].

PURPOSE: To investigate the methods of induction of mouse embryonic stem cells to differentiate into odontoblast-like cells by co-culture with pulp fibroblast. METHODS: By suspension culture, embryonic stem cells were induced to form embryoid bodies. Then the cells from embryoid bodies were co-cultured with pulp fibroblast in Transwell system for differentiation toward odontoblast-like cells. RESULTS: By RT-PCR analysis, embryoid body cells gave rise to the cell population expressing DSPP, a specific odontoblast cell marker, after 10 days of co-culture with pulp fibroblast and the expression of DSPP was enhanced after 15 days of co-culture. On the other hand, the expression of DSPP was not detected in the isolately cultured embryoid body cells. CONCLUSIONS: Embryonic stem cells can be induced into odontoblast-like cells by co-culture with pulp fibroblast. Supported by Science and Technology Development Fund of Shanghai Municipality (Grant No. 03ZR14027).

[The effect of teeth brushing education on oral health of school children].

PURPOSE: To investigate the state of oral health of children after education of teeth-brushing. METHODS: The experimental group included 145 pupils in school after education of teeth-brushing for two years. The control group included the 147 pupils in school without education of teeth-brushing. The prevalence rate of dental caries, caries average, the gingival index and the oral hygiene index-simplified were examined and statistically analyzed by chi(2) test and student's t test. RESULTS: The indexes of the prevalence rate of dental caries, caries average, GI, OHI-s in the experimental group after teeth brushing education were better than in the control group (P<0.01). CONCLUSION: The education of teeth-brushing improves the oral health of children significantly.