Finite element Stress analysis of immediate and delayed loading of solid titanium and porous tantalum single implant In edentolous maxilla model

Abstract

In conventional implant loading protocol spending a non-loading period of 3-6 months unpleasant for some of the patients due to delay of the final restoration delivery. To solve this problem immediate loading protocol was introduced. Proper stress distribution in bone surrounding implants depends on and lack of micromovement more than 150 micrometer are some of affective factors in immediate and delayed loaded implants as well as factors such as implant material and design. If the modulus of elasticity of the implant material, is close to the bone, stress distribution will be improved. Porous structure, creates more surface area and gets better stress distribution In this research by simulating and evaluation immediate and delayed loading condition in control (solid titanium) and study (porous tantalum) zimmer Indiana implant models with 4.7mm diameter and 11.5mm length we will compare these two protocols for stress distribution by finite element stress analyzing method. In this study a force of 100n was applied vertically in center of cingulum of modeled crown to simulate delayed loading, bone-implant surface designed connected, for immediate loading protocol a coefferent of friction was considered for this area. Results obtained from this finite element analyze showed more homogeneous stress distribution in boath trabecular and cortical bone around tantalum implant under both loading protocols. In delayed loading condition highest value of stress was approximately 0.8 megapascals in boath implant models, under immediate loading protocol however the highest amount of stress was 11.8MPa in titanium and 2.2Mpa in tatnalum implant model. In delayed loading condition micromovement of tantalum model was 25 and titanium model 30 micrones. Under immediate loading 40 micrones of vertical movement was evaluated for titanium implant and for porous tantalum implant this amount was 37.5 micro meters. Under immediate loading conditions micromovement of the solid titanium implant was more than the other fixture and bone around titanium implant had a more non-uniform distribution. Despite existence of micro movement in all of the four models, none of them had more than 150 micro movement which is threshold of implant encapsulation and failure.