In-vitro evaluation of the effects of insertion and sterilization procedures on the mechanical and surface characteristics of mini screws

Abstract

Purpose The aim of the present study was to investigate the effects of insertion and sterilization on primary stability and to examine the mechanical and surface characteristics of mini screws. Materials and methods 140 miniscrews (70 Dual-Top; 70 Ortho-Easy) were divided into 3 groups. Group 1: control group, 10 miniscrews of each brand, evaluated without any primary procedure. Group 2: 30 miniscrews of each brand, each inserted into the sawbone once, then sterilized and tested. Group 3: 30 miniscrews of each brand, each inserted into the sawbone twice, sterilized after each insertion and then tested. The miniscrews were evaluated for changes in primary stability, mechanical and surface characteristics with scanning electron microscopy (SEM) analysis, torsion tests, maximum insertion-removal torques and vertical-horizontal pull out strength tests. Results The maximum insertion torque values of the unused miniscrews (Group 1) were found to be significantly higher than those of the reused (Groups 2, 3) mini screws (p