Effect Of Static And Shaking Culture On Adhesion Of Streptococcus Mutans To The Surface Of Restorative Materials In Vitro

After teeth get missed ,patients wearing denture is effect method to restore some oral functions such as mastication, pronunciation, esthetic appearance.However, when dental restorative materials is put into mouth as a variant substance, some changes in microecological conditions like caries or periodontitis may take place in mouth. Adherence and colonization of micirobe on dental restorative materials is first and vital step for further aggravation. The process of adhesion is complex and affects by many factors,such as materials used ,surface characters,acquired pellicle, components of saliva. The oral conditions for restoration is a dynamic environment, and there is no report if flow of saliva caused by complex oral function ,such as mastication, pronunciation, rinsing,affects microbe attahing to dental materials. PurposeTo compare the adhesion of s.mutans to two dental restorative materials in different incubation condition (static and shaking incubation), and study the effect of vibration frequency on the adhesion,so as to test the influence of the oral activities to bacteria adhesion. Materials and methodsThe columniform specimen made of acrylic resin and dental Co-Cr alloy were polished step by step.Then the specimen were separately put into liquid BHI culture medium in which there are strptococcus mutans (ATCC 25175) and incubate in the condition of different vibrating speed for 24h.Afterwards the adhesive microbial amount and microbial amount in the culture medium were determined by the clone forming unit counting method,and adhesion morphology was analyzed with SEM. Results1. There are more adhesive microbe on both materials by stationary incubation method that by shaking incubation method ; and the differences are statistically significant (P<0.05).2. When the vibrating frequency exceeds 60r/min in acrylic resin group and 30 r/min in dental Co-Cr alloy group , the adhesive microbial amount declines while shaking frequency increases .3. SEM photos show that streptococcus mutans distribute relatively equally in stationary incubation groups and tend to gather and chain each orther,while in shaking incubation groups a larger proportion of streptococcus mutans is found in nicks and defects on surface of specenen.4. When the vibrating frequnce is between 0r/min-90r/min ,the amount of streptococcus mutans ascends while shaking frequency increases. While frequency still increases beyond 90r/min, theamount of mutans decreases. ConclusionThe results show that with the increase of vibrating frequency,the adhesive streptococcus mutans on surface of both dental materials declines,and it suggests oral functional movement may lead to decrease the adherence of microbe on the surface of dental restorative marterials ,and arcylic resin is more easy to attach oral microbe than dental Co-Cr alloy.