Evaluation of decontamination methods of oral biofilms formed on screw-shaped, rough and machined surface implants: an ex vivo study

To evaluate the effect of several representative decontamination methods of oral biofilms on different implant surfaces.

Eleven participants wore a hard resin splint carrying 6 rough (GC Aadva® implant; 3.3-mm diameter, 8-mm length) or machined (not commercially available) surface implants for 4 days to accumulate dental plaque naturally on the titanium surfaces of the implants. Apart from surface roughness, the morphology of all implants was identical. After detaching the implants from the splints, the ability of the following decontamination methods—gauze soaked in saline (G), ultrasonic scaler (US), air abrasive (Air), rotary stainless steel instrument (Rot), and Er:YAG laser (Las)—to cleanse the contaminated implant surface for 1 min extra-orally was tested. The control (Cont) group did not receive any decontamination. Scanning electron microscopic (SEM) investigation of one participant’s samples was employed to examine the post-instrumented implant surface for qualitative analysis, and bacterial culture of the remaining 10 participants’ samples was performed to count the number of colony-forming units (CFU) for quantitative analysis. The experimental sequence was initially performed for the rough surface implants and then similarly repeated for the machined surface implants. Bacterial CFU counts among the six groups were analyzed using the Steel-Dwass test, and differences between rough and machined surface implants were determined using the Mann-Whitney U test.

G and Rot eliminated most biofilms on machined surface implants according to SEM analysis. G, Air, and Rot removed significantly more of the biofilms on rough and machined surface implants compared with US according to CFU counts. Moreover, G significantly reduced more biofilms than Las on machined surface implants. The analysis between rough and machined surface implants showed that Cont, G, and US were better able to cleanse biofilms on machined surface implants compared with rough surface implants.

Gauze soaked in saline and rotary stainless steel instruments may be advantageous for cleansing contaminated implant surfaces based on the qualitative and quantitative analyses. In contrast, air abrasives were not shown to be preferable in the qualitative analyses. Additionally, apart from the Er:YAG laser, the reduction of biofilms assessed in both qualitative and quantitative analyses demonstrated that all decontamination methods were better at cleansing machined surface implants compared with rough surface implants.