Evaluation of stress distribution of fixed partial dentures over straight and inclined implants in various macrodesigns by the photoelastic stress analysis method

Serhat Emre Ozkir; Hakan Terzioglu; Ahmet Kursad Culhaoglu

doi:10.4103/2278-9626.112321

European Journal of General Dentistry, Table of Contents

CC BY-NC-ND 4.0 · European Journal of General Dentistry 2013; 2(02): 163-168
DOI: 10.4103/2278-9626.112321

Original Article

Evaluation of stress distribution of fixed partial dentures over straight and inclined implants in various macrodesigns by the photoelastic stress analysis method

Authors

Serhat Emre Ozkir

Department of Prosthodontics, Afyon Kocatepe University, Faculty of Dentistry, Afyonkarahisar, Turkey
Hakan Terzioglu

¹Department of Prosthodontics, Ankara University, Faculty of Dentistry, Besevler, Turkey
Ahmet Kursad Culhaoglu

²Doktor Mediha Eldem Sokak. No: 70/11 Kocatepe, Ankara, Turkey

Abstract

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Abstract

Aims: Tooth loss results in many problems, such as functional and esthetic problems, which may also have psychological implications. Dental implants are revolutionary improvements in functional and esthetic rehabilitation. Biomechanics is the one of the main factors for achieving the long-term success of implant-supported prostheses. It is important to distinguish the effects of macrodesign differences over stress distribution. Materials and Methods: In this study, the photoelastic response of four different types of implants that were inserted with different angulations and restored with 3-unit fixed bridges were comparatively analyzed. The implant types investigated were screw cylinder (ITI, Straumann AG, Basel, Switzerland), stepped cylinder (Frialit2, Friadent GmbH, Manheim, Germany), root form (Camlog Rootline, Alatatec, Wilshelm, Germany) and cylindrical implant with microthreads on implant neck (Astra, AstraTech, Mölndal, Sweden). In the test models, one of the implants was inserted straight while the other one was aligned mesially with 15° angles. Superstructures were prepared as 3-unit fixed partial denture FPD restorations. A 150 N loading was applied to the restorations throughout the test. Observations showed that misaligned implants caused less stresses than the straight implants, but the stress concentrations were not homogenous. Results: The comparison of implant designs showed that there were no significant differences between straight implants; however, between inclined implants, the most favorable stress distribution was seen with the stepped cylinder implants. The least favorable stress concentration was observed around the root-formed implants. Microthreads around the implant neck appeared to be effective in homogenous stress distribution. Observations showed that misaligned implants caused less stresses than the straight implants but the stress concentrations were not homogenous. Conclusion: While loading on a single implant, the remaining implant was not very effective at stress distribution. Cylinder type implants were better at stress distribution then the tapered implants while stress concentrations were lower around the inclined implants than the straight implants.

Keywords

Biomechanics - inclined implants - implant macrodesigns - implant-supported fixed partial denture - photoelastic stress analysis - stress distribution

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References

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