Efficacy of Disinfection Procedures for Irreversible Hydrocolloid Impression Materials

Objectives: This study primarily investigated the dimensional accuracy and the antimicrobial efficacy of disinfection procedures. Methods: Irreversible hydrocolloid impression materials tested were Blueprint (Dentsply, Konstanz,Germany) and Zetaplus(Zhermack, Badia Polesine, Italy). The disinfectants were Virkon (Antec International, Sudburry,UK), Carefree(Carefree Clearwater LTD, GA), Gluteraldehyde (Cidex, Johnson&Johnson Med Ltd, Skipton,UK) and Sterigum (Zhermack, Badia Polesine, Italy). Gluteraldehyde and sterigum were recommended by the manufacturer for blueprint and zhermack respectively. For the dimensional accuracy impressions were made of an edentulous mandibular metallic model containing three grooves and The difference of mean values between master and gypsum model and the percentage of change were recorded. For the antimicrobial efficacy, bacterial suspensions were prepared with the referenced strains of the microorganisms (S.salivarius I and II, S.mutans, A.viscosum). All specimens (7mm x 4mm) were contaminated in bouillon containing 109 cfu/ml one of each microorganism. Bacterial counts were recorded according to the log10 base and standardized as spectrophotometric value. Results: The mean values of three measurements after disinfection were 49.5099± 0.19256, 35.4014 ± 0.17597, 38.5711 ±0.19266. Virkon at 10, 5 and 2 minutes achieved a 4-log10 or greater reduction, as Sterigum and %2 gluteraldehyde, for all microorganisms and impression materials. In control specimens the reduction was 8-log10. Conclusion: On the basis of antimicrobial activity and dimensional accuracy, virkon may be possible alternative for the disinfection of alginate materials.