Biomechanical Evaluation of Platform Switching: Different Mismatch Sizes, Connection Types, and Implant Protocols

• Autores: Roberto S. Pessoa, Fábio J.B. Bezerra, Ravel M. Sousa, Marcio Zaffalon Casati
• Localización: Journal of periodontology, ISSN 0022-3492, Nº. 9, 2014, págs. 1161-1171
• Idioma: inglés
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• Resumen

  • Background: It is not yet well understood to what extent different implant�abutment mismatch sizes and implant�abutment connection types may influence the peri-implant biomechanical environment of implants in different clinical situations.

    Methods: Computed tomography�based finite element models comprising a maxillary central incisor socket and 4.5 × 13 mm outer-diameter implants with external and internal hex connection types were constructed. The abutments were designed with diameters of 3.5 mm (platform switching [PS] with 1 mm of diametral mismatch [PS - 1]), 4.0 mm (PS with 0.5 mm of diametral mismatch [PS - 0.5]), and 4.5 mm (conventional matching implant�abutment design [CD]). Analysis of variance at the 95% confidence interval was used to evaluate peak equivalent strain (EQV strain) in the bone, bone volume affected by a strain >4,000 ?? (EQV strain >4,000 ??), the peak von Mises stress (EQV stress) in abutment screw, and the bone�implant relative displacement.

    Results: Similar bone strain levels (EQV strain and EQV strain >4,000 ??) were encountered in PS - 1, PS - 0.5, and CD models for immediately placed implants, independent of the connection type. For immediately loaded implants, slightly smaller peak EQV strain and EQV strain >4,000 ?? were found for PS - 1. However, for both connection types in osseointegrated models, the higher the mismatch size, the lesser the amount of strain found.

    Conclusions: The increase in mismatch size of PS configuration results in a significant decrease of strain levels in bone for osseointegrated implants, principally for external hex connections. No significant effect of PS could be noted in immediately placed implants.

    KEYWORDS: Biomechanics, dental implant, abutment design, dental implants, finite element analysis, immediate dental implant loading, tensile strength