Finite element evaluation of the effect of differences in the abutment and the fixture diameters on the cervical bone stresses

Yu, Wonjae; Lee, Kyu Bok

Abstract

STATEMENT OF PROBLEM: Higher stresses at the cervical bone around dental implants have been seen as a primary cause of the bone resorption at the site. PURPOSE: To determine the possibility of stress reduction by assembly of different abutment and implant in diameters. MATERIALS AND METHODS: Abutments of several different diameters assembled on the top of XiVE(R) implants were axisymmetrically modeled for a series of finite element analyses. Abutments of 3.4, 3.8, 4.5, and 5.5 mm diameters were assumed to be sit on implants of the same or bigger diameters. All the abutments with an exception of 3.4mm dia. are technically possible to be assembled on bigger implants. Main consideration was given to the stresses at the cervical cortical bone induced by loads of parallel to the implant axis. RESULTS AND CONCLUSIONS: 1. Higher stresses were observed at the cervical area of all the models of the same diameters of abutment and fixture. The peak stresses, which were shown to be a function of the fixture diameter, were from 1-1.85MPa. 2. Difference in the diameters of the abutments and the implants actually reduced the cervical bone stresses. 3. Downsizing of the abutment by one step resulted in 0.1MPa (5%) reduction of the stresses. In light of the relatively lower bone stress, however, this amount of stress reduction was decided to be biomechanically insignificant.