Implant Volume Loss, Misfit, Screw Loosening, and Stress In Custom Titanium and Zirconia Abutments.

Sales Antônio Barbosa Jr,Ricardo Armini Caldas,Rafael Leonardo Xediek Consani,Ataís Bacchi,João Felipe Bruniera,Yara Teresinha Corrêa Silva-Sousa,Valentim Adelino Ricardo Barão

doi:10.1590/0103-6440202003643

Abstract

The aim of this study was to verify the effect of the implant volume loss, vertical misfit between abutment and prosthetic platform, prosthetic screw loosening torque, and screw stress distribution in titanium and zirconia abutments. Ten CAD/CAM system custom abutments of each material were milled and attached to the titanium implants. The implant volume loss was evaluated by microtomography, the vertical misfit with optical microscopy, and digital torque wrench measured the prosthetic screw loosening. All experimental analyses were performed before and after mechanical cycle (1,000,000 cycles, 100 N/2 Hz). Virtual models of the structures were created for finite element analysis, and the stress on the screw obtained with von Mises procedure. Data were analyzed using an independent t-test, two-way ANOVA for repeated measures, and Tukey's HSD test (a=0.05). There was no significant difference in the implant volume loss for the two abutment materials (p=0.662). Titanium abutments provided higher loosening torque values after mechanical cycling (p<0.001). Lesser marginal misfit was obtained with titanium abutments before and after mechanical cycling (p<0.001). The stress distribution on the screw was similar between abutment materials. In conclusion, CAD/CAM custom titanium abutment reduced the marginal misfit and increased the torque maintenance of prosthetic screws when compared to CAD/CAM custom zirconia abutment.

Highlights

Despite the recognized success of dental implants, mechanical problems associated with implant-supported single crowns are still a challenge to the dentist, mainly in relation to loosening and fracture of the prosthetic screws [1,2]
Screw Loosening Torque ANOVA showed that the factors abutment material (p=0.398) and mechanical cycling (p=0.099) were not significant for screw loosening torque, the factors interaction was significant (p
This study verified the mechanical behavior of custom titanium and zirconia abutments manufactured with the computer-aided design (CAD)/CAM system

Summary

Introduction

Despite the recognized success of dental implants, mechanical problems associated with implant-supported single crowns are still a challenge to the dentist, mainly in relation to loosening and fracture of the prosthetic screws [1,2]. The cemented technique is generally an adequate esthetic solution to cover the screw access hole, especially for tilted implants [3]. CAD/CAM milled lithium-disilicate crowns seem to be a preserving factor for dental implants [4]. Vestibular fractures are restricted to ceramic abutments and lesser gingival discoloration with zirconia abutments; but there is no differences in patient’s esthetic satisfaction between ceramic and metal abutments. Implant with internal connection and custom metal abutment showed the least mechanical complications [5]

Objectives

Methods

Results

Conclusion