Bacterial Adhesion on Direct Metal Laser Sintering Titanium, Zirconia, and Polyether Ether Ketone Dental Implant Abutments: An In vitro Study

Introduction: Microbial adhesion on dental implant abutment can compromise the soft-tissue seal and result in periimplant infection. The aim of the present study is to compare the adherence of Streptococcus mutans , Streptococcus sanguinis , and Escherichia coli on the surface of direct metal laser sintering (DMLS) titanium, zirconia, and polyether ether ketone (PEEK) dental implant abutment materials. Settings: The study was conducted in the Department of Prosthodontics and Crown and Bridge, Government Dental College, Thiruvananthapuram. Design: The study design was in-vitro observational study. Materials and Methods: Disks of 2 mm thickness and 8 mm diameter of each material were placed in trypticase soy broth inoculated with E. coli and brain heart infusion broth inoculated with S. mutans and S. sanguinis , and incubated at 37°C for 72 h under agitation mode. The microorganisms adhered to the samples were extracted and plated for viable count. Surface roughness was evaluated using a profilometer, and average surface average roughness was estimated for each of the materials. The contact angle of each disk was computed. Statistical Analysis Used: One-way analysis of variance test ( F -test) and Scheffe multiple comparisons ( post hoc test) were carried out to compare quantitative parameters. Results: There was a statistically significant increase in the mean bacterial adherence of S. mutans in Zirconia (13.1 ± 4.8) as compared to PEEK (5.5 ± 0.5) ( P < 0.05). S. sanguinis in DMLS Titanium (11.4 ± 0.9) and E. coli in PEEK. Titanium exhibited the highest surface roughness and contact angle. Conclusions: Bacterial adhesion on DMLS titanium, zirconia, and PEEK presented varied results depending on the organisms tested. S. sanguinis adhered more to DMLS titanium and S. mutans showed more affinity toward zirconia, and E. coli adhered more to PEEK. Although DMLS titanium showed the highest surface roughness and contact angle, no significant correlation between surface characteristics and bacterial adhesion could be drawn.