Effectiveness of various decontamination methods on CAD/CAM camera mirror sleeves

Aim: The purpose of this study was to evaluate the effectiveness of several methods of disinfection and sterilization of computer-aided design/computer-aided manufacturing (CAD/CAM) camera mirror sleeves (Omnicam; Dentsply Sirona). Materials and methods: The outer surface of seven groups of mirror sleeves were inoculated by submerging them in suspensions of Staphylococcus aureus and Pseudomonas aeruginosa. Post inoculation, the groups were decontaminated as follows: Group A: no decontamination or sterilization following inoculation (positive control); Group B: surface cleaning with a neutral soap (Dawn Dish Soap, Procter & Gamble) and water only; Group C: surface disinfection with 17% isopropanol (CaviWipes; Metrex). Groups D to F received a different high-level disinfection (HLD) solution in an HLD container (Dentsply Sirona) as follows: Group D: 0.55% ortho-phthalaldehyde (OPA) (Cidex OPA; Johnson & Johnson); Group E: 7.5% hydrogen peroxide (H2O2) (Sporox II; Sultan); Group F: 7.35% H2O2 and 0.23% peracetic acid (PAA) (Compliance; Metrex). Group G received dry-heat sterilization (Rapid Heat Sterilizer; Cox). Also, dry-heat sterilized mirror sleeves that were not exposed to bacteria and not disinfected served as a negative control. The presence of bacteria was tested on the inside and outside of the sleeves by plating samples on TSA II. A percent reduction in CFU/ml from the positive control group was determined per group. Results: All methods of disinfection except Dawn Dish Soap resulted in greater than 99.99% reduction in CFU/ml compared with the positive control group. Conclusions: Both HLD or dry-heat sterilization resulted in no growth of microorganisms in cultures taken from both the outside and inside surfaces of the bacteria-contaminated mirror sleeves. Keywords: bacteria, decontamination, CAD/CAM, mirror sleeves