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UBC Theses and Dissertations

Chemotherapeutic decontamination of dental implants colonized by multispecies oral biofilm Dostie, Sébastien


Objectives: A recent meta-analysis reported that 18.8% of patients treated with dental implants are affected by peri-implantitis. Chemotherapeutic agents are often used during surgical decontamination of the dental implant despite limited evidence to support their efficacy. It is also known that mature biofilms are more resistant to antimicrobial agents. No studies have tested disinfectants on mature multispecies oral biofilms on titanium substrata. The aim of this study is to develop a multispecies oral biofilm implant model and to determine its susceptibility to antimicrobial agents. The null hypothesis is that no chemical agent is more effective than saline rinse to decontaminate sandblasted acid etched (SLA) titanium dental implant. Methods: Collagen-coated SLA titanium discs were inoculated with dispersed dental plaque with minimum bacterial cell concentration of 3.2 × 10⁷ CFU/ml. After 21 days of anaerobic incubation, discs were rinsed with 0.9% NaCl to remove unattached biofilm, and exposed for 2 minutes to tetracycline paste, 1% chlorhexidine (CHX) gel, 35% phosphoric acid gel. Discs were rinsed again to remove the chemical agents. Bacterial counts were quantified from standardized scanning electron micrographs of the implant surface. Disinfectants were compared within each other and with the control groups (rinse and double-rinse). Results: After three weeks, the biofilm thickness on SLA discs was approximately 30 µm and showed the presence of multitude of rod and coccoid organisms. Rinsing the surfaces with 0.9% NaCl removed the majority of the biofilm. However, bacteria persisted in all specimens regardless of the treatment and none of the disinfectants was superior to the saline double-rinse group. CLSM analysis showed that CHX and Etch groups had a statistically significant reduction of viable bacteria within the biofilms, although small. New chemical and peeling-off techniques were also tested but did not remove significantly more bacteria than the double-rinse group. Conclusions: This mature multispecies biofilm model may be useful for the evaluation of decontamination of SLA implant surface. The tested chemical agents and the peeling-off techniques did not improve the decontamination effect when compared with the 0.9% NaCl rinse. CHX and Etch may provide a slight advantage in killing some of the remaining bacteria.

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