[Three-dimensional finite element analysis of implant restoration in aesthetic zone of resin-ceramic composite single crown].

PURPOSE: To observe and compare the stress distribution of implant, crown, abutment and surrounding bone tissues in the aesthetic zone after restoration of resin-ceramic composite single crown, and provide theoretical basis for clinical restoration. METHODS: Three-dimensional finite element models of alveolar bone, implant, crown, and the thickness of different adhesives between crown and abutment (0.05 mm and 0.1 mm) were established by using Mimics 17.0 software.Force was applied at the angle of 130° with the long axis of the implant, the loading position was 2 mm from the incisal cingulum, and other force on the incisal margin was loaded in parallel to the long axis of the implant. The size was 100 N. Linear static stress analysis was carried out to compare the Von Mises stress after single crown restoration with different materials. RESULTS: When the thickness of adhesive was 0.05 mm, and resin cement was selected, after restoration of Enamic, Ultimate resin ceramic composite crown, the peak stress of alveolar bone, implant, crown and abutment was more uniform and decreased slightly, but the difference was not significant compared with that of IPS Empress, blocs Mark Ⅱ ceramic crown. When the thickness of adhesive was 0.05 mm, the peak stress was significantly lower than that of 0.1 mm. There was no significant difference in the stress between glass ionomer cement and resin cement.Under the same conditions, restoration with Ultimate crown had smaller stress value of peak Von Mises. CONCLUSIONS: The stress of resin composite ceramics single crown when applied to implantation in aesthetic area is slightly less and more uniform. The proportion of resin in composites and the thickness of adhesive can affect the stress distribution and peak value.

[Effects of ultra thin porcelain veneers in repair of anterior teeth gaps].

PURPOSE: To evaluate the clinical effect of ultra thin porcelain veneers in the repair of the anterior teeth gaps. METHODS: The anterior teeth gaps in 42 patients were repaired from 2013 to 2014 with ultra thin porcelain veneers ,the clinical results of 145 porcelain veneers were evaluated at 6,12,24 and 36 months after repair. RESULTS: Thirty six months after repair, 145 ultra thin porcelain veneers were successful retained, 99.3% veneers were found to be intact.Small wane existed in one veneer at the incisal areas. 98.6% teeth had acceptable marginal adaptation .Few teeth had little hyperesthesia of dentin early after repair, but disappeared after 12 months. Patients were satisfied with the colour and shape of veneers. CONCLUSIONS: Ultra thin porcelain veneer is an satisfactory method to quickly repair anterior teeth gap.

Comparison of surface disinfection method on frequently touched objects in dental clinic / 口腔疾病防治

Objective @#To compare the bacteriostatic effect of two disinfections on the surface of frequently touched objects in dental clinic, so as to provide the reference for proper disinfection.@*Methods @#Specimens from the control panel and surface of examination table of comprehensive treatment chair were taken for bacterial culture, record the bacteria content on the objects surface. Then disinfect the objects surface by using 500 mg/L chlorine-containing disinfectant (routing group) and Gamma disinfecting wet wipes (test group) respectively, compare the qualified rate of bacteriostasis on object surfaces between two group. @*Results @# After 10-minute disinfection on surfaces, bacteriostatic rate of routing group and test group was (91.66 ± 7.52)% and (93.87 ± 6.12)% respectively, there was no significant difference between two groups (P > 0.05).@*Conclusion@#The quaternary ammonium disinfectant for the dental clinic objects can reach the same effect as chlorine-containing disinfectant.