Air-particle abrasion with Al(2)O(3) improved the shear bond strength between metal and ceramics used.

All of the techniques exhibited trueness and had acceptable precision. The variation of the angle of the implants did not affect the accuracy of the techniques.

The current study used strain gauge analysis to perform an in vitro evaluation of the effect of axial and non-axial loading on implant-supported fixed partial prostheses, varying the implant placement configurations and the loading points. Three internal hexagon implants were embedded in the center of each polyurethane block with in-line and offset placements. Microunit abutments were connected to the implants using a torque of 20 N · cm, and plastic prosthetic cylinders were screwed onto the abutments, which received standard patterns cast in Co-Cr alloy (n = 10). Four strain gauges (SGs) were bonded onto the surfaces of the blocks, tangentially to the implants: SG 01 mesially to implant 1, SG 02 and SG 03 mesially and distally to implant 2, respectively, and SG 04 distally to implant 3. Each metallic structure was screwed onto the abutments using a 10-N·cm torque, and axial and non-axial loads of 30 kg were applied at 5 predetermined points. The data obtained from the strain gauge analyses were analyzed statistically through the repeated measures analysis of variance and the Tukey test, with a conventional level of significance of P < 0.05. The results showed a statistically significant difference for the loading point (P = 0.0001), with point E (nonaxial) generating the highest microstrain (327.67 μ[Latin Small Letter Open E]) and point A (axial) generating the smallest microstrain (208.93 μ[Latin Small Letter Open E]). No statistically significant difference was found for implant placement configuration (P = 0.856). It was concluded that the offset implant placement did not reduce the magnitude of microstrain around the implants under axial and non-axial loading conditions, although loading location did influence this magnitude.

STATEMENT OF PROBLEM An imprecise fit between frameworks and supporting dental implants in loaded protocols increases the strain transferred to the periimplant bone, which may impair healing or generate microgaps. PURPOSE The purpose of this study was to investigate the microstrain between premachined 1-piece screw-retained frameworks (group STF) and screw-retained frameworks fabricated by cementing titanium cylinders to the prefabricated framework (group CTF). This procedure was developed to correct the misfit between frameworks and loaded implants. MATERIAL AND METH-ODS Four internal hexagon cylindrical implants were placed 10 mm apart in a polyurethane block by using the surgical guides of the corresponding implant system. Previously fabricated titanium frameworks (n=10) were divided into 2 groups. In group STF, prefabricated machined frameworks were used (n=5), and, in group CTF, the frameworks were fabricated by using a passive fit procedure, which was developed to correct the misfit between the cast titanium frameworks and supporting dental implants (n=5). Both groups were screw-retained under torque control (10 Ncm). Six strain gauges were placed on the upper surface of the polyurethane block, and 3 strain measurements were recorded for each framework. Data were analyzed with the Student t test (=.05). RESULTS The mean microstrain values between the framework and the implants were significantly higher for group STF (2517 m) than for group CTF (844 m) (P<.05). CONCLUSIONS Complete-arch implant frameworks designed for load application and fabricated by using the passive fit procedure decreased the strain between the frameworks and implants more than 1 piece prefabricated machined frameworks. Precision of fit between frameworks and supporting dental implants in immediately loaded protocols reduces the strain transfered to the peri-implant bone that may impair healing or generate micro-gaps. Purpose. This study investigated the microstrain between premachined one-piece screw-retained frameworks (STF) and screw-retained frameworks constructed by the procedure of cementing titanium cylinders to the pre-fabricated framework (CTF), which has been developed for correction of misfit between framework and immediately loaded implants. Material and methods. Four internal hex cylindrical implants were placed 10 mm distant to each other in a polyurethane block, using surgical guides of the corresponding implant system. Previously fabricated titanium frameworks (N=10) were distributed into 2 groups. While in group STF, pre-fabricated machined frameworks were used (n=5), in group CTF, the frameworks were constructed by a passive fit procedure, which has been developed for correction of misfit between cast titanium frameworks and supporting dental implants (n=5).CTF system was cemented first in the final cast and then screw retained to the implants. Both groups were screw-retained under torque control (10 N/cm). Six strain gauges were placed on the upper surface of the polyurethane block and 3 strain measurements...