ABSTRACT
Implant alignment is an important factor in overdentures retained by solitary abutments. In this study, the effect of implant angulations in two directions, on the amount of retention of attachments was evaluated. Ninety models were divided into nine groups of two blocks each; one for two implants and one for two attachments. The implants were placed either parallel to, at 5°, or at 10° relative to the reference plane. The attachments were related to the implants with a 0, 5, or 10° angulations. The direction of the implant was either labial or distolabial. The initial and the subsequent retention values of each sample were measured after each 500 cycles of insertion and removal. The measurements were repeated for five consecutive 3,000 cycles, and the results were analyzed by means of one-way ANOVA and Tukey HSD tests. Group 9 with a 10° distolabial tilt of the implants and of their attachments showed the highest initial retention, whereas group 1 with a 0° angulations and parallel attachments showed the lowest (6.9 ± 0.28 and 3.88 ± 0.19 N, respectively). The initial retention and the final loss of retention was significantly higher in those groups with the distolabial tilt of the implants (p < 0.05). Within the limitations of this study, it was demonstrated that the more divergent the implants and their retentive components, the higher their initial retention and the lower their final retention may be.
ABSTRACT
AIM: Occlusal errors during acryl processing affect the retention and stability of complete dentures. The aim of the present study was to assess the influence of a short curing technique on the number of occlusal contacts and the occlusal vertical dimension (OVD) of complete dentures. MATERIALS AND METHODS: Complete dentures were prepared. The number of occlusal contacts was recorded in centric relation (CR) using 60 µ articulation paper. The OVD was recorded with the waxed trial denture in place. Dentures were then invested and processed with compression molding and short cure water bath technique. The number of occlusal contacts was recorded again. The amount of pin opening was measured for all of the complete dentures on the articulator. Data were analyzed with paired t-test to determine the alterations. RESULTS: The mean number of occlusal contacts before and after processing was 10.9 ± 2.4 and 6.3 ± 3.1 respectively (4.7 ± 1.9 decrease; p < 0.001). A 2 mm mean increase in OVD was observed in 47.7% of the dentures with < 6 occlusal contact changes and 88.9% of the dentures with ≥ 6 occlusal contact changes (p < 0.003). A significant change in the number of occlusal contacts was associated with an OVD increased up to two times. CONCLUSION: The short curing technique seems to be related to the decreased occlusal contacts and increased OVD. CLINICAL SIGNIFICANCES: More time is needed to adjust the occlusal errors of this method, because it has a negative effect on the morphologic pattern of artificial teeth of complete dentures and thus should be used carefully.
