In-vivo Validated Finite Elements Analysis on Premolar Restoration Strategies

Method: The solid model consisted of MFP, periodontal ligament and the corresponding alveolar bone process. Four models were created representing different degrees of coronal tissue loss (0mm, 1mm, 2mm and 3mm). First set of computing runs was performed for in-vivo FE-model validation purposes. In the second part, a 400-N force was applied on the buccal cusp directed at 45° to the longitudinal axis of the tooth. Principal stresses values and distribution were recorded within root, abutment, posts, crown and all adhesive interfaces.

Result: All models showed similar stress distribution within roots, with highest stress present in the chamfer area. In composite abutments higher stress was observed when no ferrule was present compared to ferruled models. Stress distribution within crown and GFRR did not differ among the models. Stress values at the adhesive interfaces decreased with increasing ferrule height.

Conclusion: Irrespective of the presence of ferrule, the stress at abutment-crown and post-root interfaces overcomes their strength. Conversely, higher ferrule produced more favorable stress distribution at post-abutment and abutment-root interfaces.