Evaluation of the marginal precision of one-piece complete arch titanium frameworks fabricated using five different methods for implant-supported restorations.

摘要

OBJECTIVE: The aim of the present work was to compare the marginal precision of titanium frameworks for a complete arch-fixed prosthesis fabricated using five different methods. METHODS: A prospective study was designed. Fifteen titanium frameworks for totally edentulous upper or lower jaws, each supported by five to nine implants, were assigned to five study groups, so as to have three frameworks in each group for each technique: (1) lost wax technique frameworks, (2) cast titanium sovrastructures laser welded to prefabricated titanium copings, (3) Procera Implant Bridge, (4) Cresco Ti System and (5) CAM StructSURE Precision Milled Bar. The microgap between the framework and the shoulders of implant analogues was measured on the master cast with a stereomicroscope at a magnification of 100 x at four different locations, yielding a total of 364 data points on 91 implants. Data were analyzed using an ANOVA and a Tukey post hoc test (P=0.05). RESULTS: The mean values for the microgap were 78 microm (SD+/-48) for lost wax technique frameworks, 33 microm (SD+/-19) for cast titanium sovrastructures laser welded to titanium copyings, 21 microm (SD+/-10) for the Procera implant bridge, 18 microm (SD+/-8) for the Cresco Ti System and 27 microm (SD+/-15) for the CAM StructSURE. The differences among the mean values were statistically significant (P0.01 or P0.05). The comparisons among groups 3, 4, and 5 and between groups 2 and 5 were not significant (P0.05). CONCLUSION: The computer-aided procedures analyzed in the present study were able to produce a precision-fitting framework, with no significant differences among them and, at the same time, showed a greater precision compared with the traditional casting methods or with the use of prefabricated titanium copings. However, it should be noted that, even if group 2 frameworks were not as accurate as groups 3 and 4, cast titanium sovrastructures laser welded to prefabricated titanium copings showed significantly better marginal precision than the frameworks produced with the lost wax technique.