Electrochemical Disinfection of Dental Implants Experimentally Contaminated with Microorganisms as a Model for Periimplantitis

Abstract

Despite several methods having been described for disinfecting implants affected by periimplantitis, none of these are universally effective and may even alter surfaces and mechanical properties of implants. Boron-doped diamond (BDD) electrodes were fabricated from niobium wires and assembled as a single instrument for implant cleaning. Chemo-mechanical debridement and air abrasion were used as control methods. Different mono-species biofilms, formed by bacteria and yeasts, were allowed to develop in rich medium at 37 °C for three days. In addition, natural multi-species biofilms were treated. Implants were placed in silicone, polyurethane foam and bovine ribs for simulating different clinical conditions. Following treatment, the implants were rolled on blood agar plates, which were subsequently incubated at 37 °C and microbial growth was analyzed. Complete electrochemical disinfection of implant surfaces was achieved with a maximum treatment time of 20 min for Candida albicans, Candida dubliniensis, Enterococcus faecalis, Roseomonas mucosa, Staphylococcus epidermidis and Streptococcus sanguinis, while in case of spore-forming Bacillus pumilus and Bacillus subtilis, a number of colonies appeared after BDD electrode treatment indicating an incomplete disinfection. Independent of the species tested, complete disinfection was never achieved when conventional techniques were used. During treatment with BDD electrodes, only minor changes in temperature and pH value were observed. The instrument used here requires optimization so that higher charge quantities can be applied in shorter treatment times.

Pilot Study on the Use of a Laser-Structured Double Diamond Electrode (DDE) for Biofilm Removal from Dental Implant Surfaces

“…The double diamond electrode (DDE) used for disinfection in this study is based on the unique electrochemical behavior of boron-doped diamond (BDD) electrodes producing oxidative reagents at the anodic surface, but it differs significantly from the state of the art of BDD in literature. In general, the diamond coating is performed on metallic substrates (W, Nb, Ti) as bulk material with thin interlayers (e.g., TiC or TiN) on top for better adhesion [ 32 , 33 , 34 , 35 , 36 ]. In this newly developed double diamond system, both the anode and cathode consist of a BDD layer, which is deposited to a non-conductive ceramic substrate (porcelain, Al 4 [(OH) 8 |Si 4 O 10 ], (Ca,Na,K)(Al,Si) 4 O 8 , SiO 2 , Flügel Porzellan, Selb, Germany) by Chemical Vapor Deposition (CVD).…”

“…In this newly developed double diamond system, both the anode and cathode consist of a BDD layer, which is deposited to a non-conductive ceramic substrate (porcelain, Al 4 [(OH) 8 |Si 4 O 10 ], (Ca,Na,K)(Al,Si) 4 O 8 , SiO 2 , Flügel Porzellan, Selb, Germany) by Chemical Vapor Deposition (CVD). The diamond coating is performed by a standard hot filament CVD process [ 32 , 33 , 34 , 35 ]. Due to the addition of B(OCH 3 ) 3 gas during the coating process, the diamond layer becomes conductive (doping), while the substrate stays non-conductive.…”

“…A potential of 9 V at an average current of 105 mA was applied to the electrode. Then, the implants were rolled on Columbia blood agar as described previously [ 34 ].…”

“…The diamond coating is performed by a standard hot filament CVD process [32][33][34][35]. Due to the addition of B(OCH 3 ) 3 gas during the coating process, the diamond layer becomes conductive (doping), while the substrate stays non-conductive.…”

“…A novel approach for disinfecting hardly accessible porous structures employs the use of boron-doped diamond (BDD) electrodes and has been derived from wastewater treatment [ 31 ]. Previous investigations using simplistic arrays of single electrodes have shown that electrochemical disinfection can effectively inactivate monospecies biofilm both during root canal treatment [ 32 ] and peri-implantitis treatment [ 33 ] without affecting surface characteristics, as may be the case with the use of curettes and airflow instruments [ 34 ]. Further developing this technology for clinical application, it was the goal of this study to fabricate and test a novel laser-structured, ceramic-based BDD electrode array for removing wild-type multispecies biofilm.…”