Optimum Design of the Dental Air-Turbine Handpiece System Using the Design of Experiment Method

Abstract

An air-turbine and associated air supply tube was optimized as a dental air-turbine handpiece system. The system consists of an air-turbine with an impeller and a housing, and an air supply tube which supplies compressed-air to the air-turbine. The flow characteristics of the dental air-turbine handpiece system were investigated using ANSYS CFX. The study aimed to find the significant design parameters, and optimize them in terms of the maximum torque. The number of blades, the blade angle of the impeller and the gap between the impeller and the housing were chosen as the three major design parameters. The design of experiment technique was used to optimize two dental air-turbine handpiece systems: Type 1 was an air turbine alone and Type 2 was the air-turbine with an air supply tube. The optimization results showed that the gap between the impeller and the housing was not a significant parameter for Type 1. The maximum torque was lower for Type 2 than for Type 1. The optimized optimum blade number was the same for both types, but the blade angle and the gap differed between the two types. The blade angle and blade number were significant for Type 1, and all three design parameters were significant for Type 2. The performance improvement was greater for Type 2 than for Type 1. The performance of both optimized handpiece systems was reviewed in terms of the experimental measurements of noise level, rotational speed, and withdrawal force.