PURPOSE: This in vitro study investigated 4 impression techniques to determine their dimensional accuracy in comparison with a standard technique. MATERIALS AND METHODS: A master metal framework with 2 inner hex implants (SIN; Sistema de Implante Nacional Ltda., Sao Paulo, Brazil) was used as a standard for the comparisons. Sixty master casts were prepared to evaluate 4 impression techniques: (1) indirect impression technique with tapered transfer copings, (2) direct impression technique with unsplinted squared transfer copings, (3) direct impression technique with squared transfer copings splinted with acrylic resin, and (4) direct impression technique with squared transfer copings with acrylic resin splints sectioned 17 minutes after setting and welded with the same resin. A profile projector was used to measure the distance between the copings attached to the analogs. Mean distances (mm) were calculated from 3 measurements for each sample in the master casts and in the master metal framework. RESULTS: Analysis of variance and the Tukey HSD test were used for statistical analysis of data (alpha = 0.05). The results for the direct technique with squared transfer copings with acrylic resin splints sectioned and welded after setting were not significantly different from results for the master metal framework. CONCLUSION: Considering the methodology used and the results obtained, the direct impression technique with squared transfer copings with acrylic resin splints sectioned and welded after setting had better results than the other techniques studied.
PURPOSE: This in vitro study investigated 4 impression techniques to determine their dimensional accuracy in comparison with a standard technique. MATERIALS AND METHODS: A master metal framework with 2 inner hex implants (SIN; Sistema de Implante Nacional Ltda., Sao Paulo, Brazil) was used as a standard for the comparisons. Sixty master casts were prepared to evaluate 4 impression techniques: (1) indirect impression technique with tapered transfer copings, (2) direct impression technique with unsplinted squared transfer copings, (3) direct impression technique with squared transfer copings splinted with acrylic resin, and (4) direct impression technique with squared transfer copings with acrylic resin splints sectioned 17 minutes after setting and welded with the same resin. A profile projector was used to measure the distance between the copings attached to the analogs. Mean distances (mm) were calculated from 3 measurements for each sample in the master casts and in the master metal framework. RESULTS: Analysis of variance and the Tukey HSD test were used for statistical analysis of data (alpha = 0.05). The results for the direct technique with squared transfer copings with acrylic resin splints sectioned and welded after setting were not significantly different from results for the master metal framework. CONCLUSION: Considering the methodology used and the results obtained, the direct impression technique with squared transfer copings with acrylic resin splints sectioned and welded after setting had better results than the other techniques studied.