Stress distributions in maxillary bone surrounding overdenture implants with different overdenture attachments

Abstract

In this study, effects of different overdenture attachments on the stress distributions in the maxillary bone surrounding the overdenture implants are studied. Four different types of attachment are considered. They are rigid Dalbo Stud, movable Dalbo Stress Broken, movable Dalro, and movable O-ring attachments. Three-dimensional finite element analysis was conducted with commercial package to obtain the stress distributions in the maxillary bone. Varying the attachment types and angle of inclination of load, the stress distributions in the portions of compact bone and trabecular bone were monitored separately. The analysis was conducted by assuming two different boundary conditions at the interface between cap and overdenture abutment in order to evaluate influence of interface boundary condition on stress distribution in the maxillary bone. They were perfect bonding condition and contact with friction at the interfaces. However, it is preferable to assume perfect bond condition at the interface for rigid type attachment systems and contact with friction at the interface for movable type attachment systems. From the numerical results, it was found that the load transfer mechanism of the implant system is altered significantly by the types of the overdenture attachment and also special care must be taken to assign proper boundary conditions at the interface for the analysis. The movable type Dalro attachment generated the highest maximum effective stress in the maxillary bone among the models under the same inclined loading condition for contact with friction. The rigid type Dalbo Stud attachment generated the smallest maximum effective stress in the maxillary bone among the models under the same inclined loading condition for perfect bonding condition.

The influence of implant diameter and length on stress distribution of osseointegrated implants related to crestal bone geometry: A three-dimensional finite element analysis

“…In agreement with a number of studies, [33][34][35][36][37][38][39][40][41][42][43][44][45][46][47][48][49][50][51][52] the von Mises stress field (σ VM ) was used as an indicator of the average stress level at the periimplant region, providing a global measure of load transfer mechanisms. Moreover, in agreement with the maximum normal stress criterion, 60 principal stresses were used at the bone-implant interface to define local risk indicators of physiological bone failure and of the activation of bone resorption.…”

“…Implants and abutments were assumed to be constituted of a titanium alloy, Ti6Al4V, with a Young's modulus and Poisson's ratio of 114 GPa and 0.34, respectively. 42,56 In agreement with data available in the literature, the Poisson's ratio of bone tissue (both cortical and trabecular) was assumed to be 0.3, 52 Young's modulus of both maxillary and mandibular cortical bone was assumed to be 13.7 GPa, 42,57 and Young's modulus for maxillary (mandibular) cancellous bone was set to 0.5 GPa 52 (1 GPa 42 ). These properties approximate type II bone quality, 58 and maxillary trabecular bone was assumed to be less dense than mandibular, resulting in a smaller Young's modulus.…”

Importance of diameter-to-length ratio in selecting dental implants: a methodological finite element study

“…Implants and abutments were assumed to be manufactured from titanium alloy Ti6Al4V, with the modulus of elasticity (Young's modulus) and Poisson's ratio of 114 GPa and 0.34, respectively (Lemons and DietshMisch 1999;Bozkaya et al 2004). Poisson's ratio of bone tissue (both cortical and cancellous) was assumed to be 0.3 (Meijer et al 1992(Meijer et al , 1993Papavasiliou et al 1996;Menicucci et al 2002;Himmlova et al 2004;Chun et al 2005;Caglar et al 2006;Baggi et al 2008;Chou et al 2010). Young's modulus for mandibular cortical bone was 13.7 GPa (Carter and Hayes 1997;Borchers and Reichart 1983;Meijer et al 1992Meijer et al , 1993Papavasiliou et al 1996;Van Oosterwyck et al 1998;Menicucci et al 2002;Ishigaki et al 2003;Bozkaya et al 2004;Himmlova et al 2004;Caglar et al 2006;Anitua et al 2010), and that for a mandibular cancellous bone was 1.0 GPa (Papavasiliou et 1996).…”

Stresses Transmitted to Tilted One-Piece Narrow-Diameter Implants Retaining Mandibular Over Dentures (A 3 Dimensional Finite Element Stress Analysis)

“…Cortical bone [20] 13700 0.30 Cancellous bone [20] 1370 0.30 Grade 4 titanium [21] 110000 0.30 Heat-curePMMA [21] 3000 0.35 Nylon rubber [22] 5 0.45…”