Comparison of occlusal contacts in maximum intercuspation for two impression techniques

Statement of problem. At the insertion of a fixed prosthesis, occlusal interferences in maximum intercuspation are often present. Purpose. This study investigated and compared the accuracy of interocclusal relationships in maximum intercuspation for mounted casts obtained from a quadrant dual-arch impression technique and conventional full-arch impression techniques. Material and methods. Comparisons were made between an intraoral interocclusal record and interocclusal records made on mounted casts. Irreversible hydrocolloid, reversible hydrocolloid, polysulfide, polyether, and polyvinyl siloxane were used for the full-arch impression technique. For the quadrant dual-arch impression technique, rigid polyvinyl siloxane and light-body polyvinyl siloxane injection materials were used. Results. Statistical analysis revealed a statistically significant difference ( p = 0.0017) in the median values among treatment groups. All pairwise multiple comparison procedures (Student-Newman-Keuls) indicated the average error of the quadrant dual-arch records was significantly different from the average error of each group of records produced with the full-arch techniques ( p < 0.05). Comparison of the records of the full-arch impressions did not reveal any statistically significant differences. The average error of the full-arch records was 72 ± 33 μm and the quadrant dual-arch average error was 5 ± 5 μm. Conclusion. The quadrant dual-arch impression technique produced mounted casts with significantly more accurate maximal intercuspal relationships than mounted casts from full-arch impressions. (J Prosthet Dent 1997;78:255-9.).