Possibilities of Gutta-Percha-centered Infection in Endodontically Treated Teeth: An In Vitro Study

Introduction: Implanted biomaterials could provide surface for bacterial adherence and formation of biofilm, eventually leading to biomaterial-centered infections (BCIs). In this in vitro study, we examined the biofilm-forming capacity of Enterococcus faecalis on gutta-percha (GP) points under different nutrient status and surface conditioning with saliva and serum. Methods: GP points (n = 420) coated with different root canal sealers (Sealapex or Roth) were conditioned with saliva or serum for 2-, 4-, and 12-week intervals and subsequently were incubated with E. faecalis for 2 weeks under nutrient-rich and nutrient-deprived environments. The biofilm-forming capacity and the nature of biofilm formed on GP were assessed by using a viable cell assay and scanning electron microscopy (SEM). Results: E. faecalis produced biofilms on GP points (with and without root canal sealers) under both nutrient-rich and nutrient-deprived environments after conditioning with saliva or serum. SEM reflected that the biofilms formed under nutrient-rich conditions were regular, whereas the biofilms formed under nutrient-deprived conditions were irregular and scanty. Under nutrient-deprived conditions, longer conditioning periods in saliva or serum were required for bacterial adherence. Conclusions: Under the conditions of this study, saliva and serum conditioning of GP points plays an important role in the biofilm formation under tough environmental conditions. (J Endod 2010;36:1241-1244)