In vitro assessment of maximum insertion and removal torque with three different miniscrews on artificial maxilla and mandible

Abstract

ObjectiveThe aim of this study was to measure and correlate the values of maximum insertion and removal torques of miniscrews in artificial posterior maxilla and posterior mandible. This study also aimed at assessing the effect of bone density and screw design on these values. MethodsThree groups of self-drilling miniscrews obtained from three different manufacturing companies, having same diameters (1.4 mm) and lengths (8 mm) were used. All screws were inserted in artificial bone samples (Sawbones) and the maximum insertion and removal torque values were recorded with digital torque sensor. ResultsThere were significant differences, statistically, between maximum insertion and removal torque values of different groups of miniscrews. Insertion torque values in the posterior mandible were significantly higher than those in the posterior maxilla and the maximum insertion and removal torques were directly proportional to each other. ConclusionIt is suggested to perform a pre-insertion drilling due to the higher insertion torque in the posterior mandible, to maintain an acceptable range of maximum insertion torque and achieve primary stability without unnecessary bone damage. It is concluded that the screw design as well as bone characteristics have significant effects on the stability of the screw.