Filling Materials Efficacy on Preventing Biofilm Formation Inside Screw Access Channels of Implant Abutments

Abstract

The choice of the material used to fill screw access channels in implant-supported prostheses depends, in most cases, on operator's preference, without considering the susceptibility of biofilm colonization. Therefore, the aim of this study was to determine and compare the total amount of biofilm formed on different materials used to fill screw access channels in implant abutments. For this propose, titanium implant analogs were attached on abutments and divided into 5 groups: positive control (no filling material); negative control (closed with resin); and filled with cotton, gutta-percha, or polytetrafluoroethylene (PTFE). The analogs with attached abutments were then immersed in a brain heart infusion medium containing Candida albicans (strain 10231 from American Type Culture Collection [ATCC]) and incubated aerobically at 37°C with gentle agitation. After 15 days, materials were removed, and total viable biofilm on each material was quantified by methyl tetrazolium reduction assay at 490 nm. All experiments were performed in triplicate. Data were processed by IBM SPSS Statistic software using 1-way analysis of variance and Bonferroni post hoc tests to analyze differences between groups, with an overall significance level of P < .001. A significant difference was observed between cotton and gutta-percha (P < .017) and between cotton and PTFE (P < .025). However, there was no statistical difference between gutta-percha and PTFE (P > .050). Thus, this in vitro experiment showed that gutta-percha and PTFE presented lower biofilm formation compared with cotton when used to fill screw access channels. These results can provide a basis for future clinical studies that can be a guide to decreasing the occurrence of gaps and bacterial growth inside the implant/abutment attachment site. In addition, controlled in vivo studies are necessary to confirm the clinical viability of findings of this study.