Stress on implant-supported fixed prostheses with different numbers of abutments after the application of acrylic resin

Statement of problem. Clinical procedures and laboratory processing techniques inevitably induce stress in the implant/abutment/prosthesis system and may have negative effects when different numbers of implants are used. Purpose. The purpose of the study was to evaluate the tension on the abutments of implant-supported fixed prostheses and to determine the effect of the application of an esthetic veneer (acrylic resin) and the number of abutments (5 or 4). Material and methods. Four palladium-silver alloy cast bars were fabricated to simulate implant-supported fixed complete prostheses. Strain gauges were fixed on the abutments to measure the tension before and after the application of the esthetic veneer. The values of tension were measured in models with 5 or 4 abutments. Data were analyzed with a repeated measures ANOVA. Results. No statistically significant differences were found for the main factors (esthetic veneer, P=.22; number of abutments, P=.14) despite the large effect size. Conclusions. The results of this study suggest that the tension in the abutments of an implant-supported fixed prosthesis is not affected by the application of acrylic resin veneering or by reducing the number of abutments.