Early bacterial colonization on CAD/CAM dental materials

Bacterial adhesion on dental restorative materials, prostheses, and various oral appliances poses a significant risk for the development of secondary caries, periodontal disease, peri-implantitis, denture stomatitis, and other conditions. Thus, reducing bacterial colonization on different dental materials is a key milestone in contemporary dental material science. Despite being introduced in dentistry fifty years ago, computer-aided design and computer-aided manufacturing (CAD/CAM) technology continues to play a significant role in modern dentistry. The aim of this study was to investigate bacterial adhesion on five different CAD/CAM-derived dental materials: resin-based composite (RBC), polymethyl methacrylate (PMMA), zirconia glazed (ZG), cobalt- chromium (CoCr) alloy, and polyetheretherketone (PEEK). The study included ten healthy volunteers who were instructed to carry individually made intraoral splints embedded with five different CAD/CAM-prepared discs (50 in total). After 24 hours of intraoral exposure, discs were removed from the splints, briefly soaked in saline and then subjected to bacterial DNA isolation procedure. Bacterial load on each CAD/CAM disc was quantified by real-time polymerase chain reaction. Collected data were analyzed on SPSS v25.0 (IBM SPSS, Chicago, IL, USA) statistical package and presented as median±IQR. PEEK specimens exhibited the highest amount of adhered bacterial biofilm (33.25±40.12×10E13), while RBC specimens had the least bacterial accumulation compared to all other materials (2.66±7.33×10E13). Bacterial load on RBC was significantly lower than on ZG (p=0,039) and PEEK (p=0.004). In addition, cobalt-chromium alloy collected fewer bacteria than PEEK (p=0.015). The results of this study suggest that CAD/CAM RBC is advantageous for use in oral environment compared to other tested materials.