Antiviral effects of different sterilization and disinfection methods on internal tubes of dental handpiece

Dental handpieces are the most commonly used instruments in dentistry and their cross contamination is very high due to their direct contact with blood and saliva. The purpose of this study was to evaluate the antiviral effects of formalin tablets and autoclave on internal lumens of dental handpieces. This experimental study was designed in order to evaluate the effect of different materials and methods of sterilization and disinfection on virus elimination from internal spaces and interior chambers of dental turbines. Four study groups were composed of: 1) Vacuum autoclave, 2) Non vacuum autoclave, 3) Ten Para Formaldehyde tablets, and 4) Twenty Para Formaldehyde tablets. Nine turbines were tested in each group after preliminary washing, drying and autoclaving. The internal tubes and spaces were then contaminated with Polio and Herpes Simplex virus type I. Antiviral agents and devices were used according to the manufacturers’ instructions. Two cell culture samples were obtained from each handpiece, after washing them with sterile distilled water and MEM (Minimum Essential Medium). In each group one handpiece was designated as control. The culture results were recorded after one week. Autoclaving was perfectly effective on both Polio and Herpes Simplex virus type I in all groups (vacuumed, non-vacuumed, with or without lubricant). Formalin tablets were 100% effective only on polio virus, and in the 20 tablet group turbines without lubricant. These tablets killed the Herpes Simplex virus in all groups. According to the results of this study, autoclaving is the best method of virus elimination in dental handpiece.