RESUMEN
Purpose@#The aim of this study was (1) to compare the reverse engineering technique with other existing measurement methods and (2) to analyze the effect of implant angulations and impression coping types on implant impression accuracy with reverse engineering technique. @*Materials and methods@#Three different master models were fabricated and the distance between the two implant center points in parallel master model was measured with different three methods; digital caliper measurement (Group DC), optical measuring (Group OM), and reverse engineering technique (Group RE). The 90 experimental models were fabricated with three types of impression copings for the three different implant angulation and the angular and distance error rate were calculated. One-way ANOVA was used for comparison among the evaluation methods (P .05). The standard deviations in reverse engineering were much lower than those of digital caliper and optical measurement. Hybrid groups had no significant difference from the pick-up groups in distance error rates (P > .05). @*Conclusion@#The reverse engineering technique demonstrated its potential as an evaluation technique of 3D accuracy of impression techniques.
RESUMEN
Purpose@#The aim of this study was (1) to compare the reverse engineering technique with other existing measurement methods and (2) to analyze the effect of implant angulations and impression coping types on implant impression accuracy with reverse engineering technique. @*Materials and methods@#Three different master models were fabricated and the distance between the two implant center points in parallel master model was measured with different three methods; digital caliper measurement (Group DC), optical measuring (Group OM), and reverse engineering technique (Group RE). The 90 experimental models were fabricated with three types of impression copings for the three different implant angulation and the angular and distance error rate were calculated. One-way ANOVA was used for comparison among the evaluation methods (P .05). The standard deviations in reverse engineering were much lower than those of digital caliper and optical measurement. Hybrid groups had no significant difference from the pick-up groups in distance error rates (P > .05). @*Conclusion@#The reverse engineering technique demonstrated its potential as an evaluation technique of 3D accuracy of impression techniques.
RESUMEN
PURPOSE: The aim of this study is to evaluate the effects of various primers on the microtensile bond strength (µTBS) of resin cements to cobalt-chromium (Co-Cr) dental casting alloy. MATERIALS AND METHODS: Four adhesive primers (Universal primer, Metal primer II, Alloy primer, and Metal/Zirconia primer) and two resin cements (Panavia F2.0, G-CEM LinkAce) were tested. One hundred fifty Co-Cr beams were prepared from Co-Cr ingots via casting (6 mm length × 1 mm width × 1 mm thick). The metal beams were randomly divided into ten groups according to the adhesive primers and resin cements used; the no-primer groups served as the control (n = 15). After sandblasting with aluminum oxide (125 µm grain), the metal and resin cements were bonded together using a silicone mold. Prior to testing, all metal-resin beams were examined under stereomicroscope, and subjected to the µTBS test. The mean value of each group was analyzed via one-way ANOVA with Tukey's test as post hoc (α = .05) using SPSS software. RESULTS: The mean µTBS of all groups was ranged from 20 to 28 MPa. There is no statistically significant difference between groups (P > .05). Mixed failure, which is the combination of adhesive and cohesive failures, is the most prevalent failure mode in both the Panavia F2.0 and G-Cem LinkAce groups. CONCLUSION: The µTBS of all tested groups are relatively high; however, the primers used in this study result in no favorable effect in the µTBS of Panavia F2.0 and G-Cem LinkAce resin cement to Co-Cr alloy.