Microbiological analysis of different prefabricated fiberglass posts

Objective: This study aims to evaluate the presence of microorganisms in fiberglass posts available in the dental market, aiming to better understand the contribution of these devices to maintaining asepsis after their insertion into the root canal. Materials and methods: Fifty-four smooth conical fiberglass posts from six different commercial brands were selected (n=9 for each brand): Whitepost DC-E®, Exacto®, Fiber Post®, Superpost®, Power Point®, and Rebilda Post®. Microbiological analyses were conducted by submerging the posts in tubes containing Brain-Heart Infusion (BHI) broth and then inoculating an aliquot of this broth onto four different culture media: BHI; Mitis Salivarius Agar supplemented with 1% potassium tellurite solution, M-Enterococcus Agar supplemented with 1g/L esculin; Sabouraud Dextrose Agar supplemented with 0.5g/L chloramphenicol. The number of colony-forming units (CFU/mL) in the inoculation suspension was determined by plate counting. DNA extraction was performed, and samples were analyzed in a spectrophotometer to quantify extracted DNA. After DNA extraction, the PCR technique was employed to amplify the 16S rRNA gene, followed by agarose gel electrophoresis to detect bands corresponding to amplified DNA. Results: No microbiological growth was observed in the samples from the posts on the selected culture media. PCR revealed amplification of the 16S rRNA gene in all post samples, indicating the presence of bacterial DNA. Conclusions: The evaluated fiberglass posts did not show detectable contamination through plate culturing. However, in the qualitative PCR analysis, bands indicating the presence of bacteria at concentrations not cultivable in the employed media, non-viable, or not susceptible to cultivation in these media were identified through agarose gel electrophoresis.