DESCRIPTION: (provided by the applicant) Frequent repair and replacement of dental handpieces (DHs) represent major dental practice costs necessitating an immediate technological solution. Dental handpiece (DH) failure is primarily caused by the combined effects of poor cleaning of internal channels and surfaces, improper or inadequate lubrication of moving parts, and repeated steam sterilization. Currently, there is no technology that is capable of delivering standardized effective cleaning and lubrication of DHs. In Phase I, we demonstrated that a novel two-phase flow method is highly effective in cleaning DH internal channels and surfaces, consistently achieving more than 5-log reduction of Bacillus spores. If this two-phase cleaning can be incorporated into a device that delivers a standardized cleaning and lubrication protocol for each reprocessing cycle, the result will be better longevity and performance. Ultimately, if a validated two-phase cleaning and lubrication protocol is combined with an approved steam sterilization cycle, key causes of DH failure may be eliminated. The better cleaning afforded by the two-phase flow method will also assure that sterilization is achieved during every use, especially for the narrow air and water channels. The outcome of the study will be the development of a two-phase cleaning and lubrication to be used with an FDA-approved steam sterilization cycle. The specific aims of the Phase II study are to: 1) develop a prototype device for cleaning and lubricating DHs based on two-phase fluid dynamics: 2) optimize DH cleaning in the laboratory using simulated soils and microbial challenges in an appropriate soil matrix using direct and indirect methods; 3) define a final validated cleaning and lubrication protocol to be coupled with steam sterilization; 4) validate the cleaning and lubrication with steam sterilization protocol for clinical DHs; and 5) evaluate the effect of cleaning, lubrication and steam sterilization protocols on the longevity and performance of DHs. This development is expected to reduce DH costs for the dental practice, standardize DH cleaning and lubrication steps, and decrease exposure of dental workers to microbial contamination compared to the current practice.