RESUMO
Background ond Aim:Complete denture's retention is an important issue which sometimes in spite of all efforts does not provide patient and dentist's satisfaction. The aim of this study was to evaluate the effect of sandblasting the impression surface on the maxillary denture retention.
Materials and Methods: In this Before and After Clinical trial, for 15 patient of the Department of Prosthodontics of the Shahed University, 2 bases similar to their original upper dentwe were prepared. By applying a digital force transducer, the force needed to dislodge the base from the patients' palate was measured. The internal surface of the bases were air abraded by 50 micron Alumina particles for I minute except for the borders which were covered by Aluminum thin foils.
Results: By sandblasting, the mean retention of the bases increased from 30.89 +/- 10.74 N to 37.66 +/- 9.76 N [21.9%] which was statistically significant [p<0.000 I].
Conclusion: According to the findings of the present study, sandblasting the intaglio surface of the maxillary complete denture with abrasive particles will enhance the retention of the denture.
RESUMO
The bond strength between veneer ceramics and zirconia frameworks is the weakest component in the layered ceramics. Due to the possible effect of adding pigments to the core materials on the bond strength between core and veneer as well as the introduction of new ceramic materials in dentistry, the aim of this study was to compare the zirconia core-veneer microtensile bond strength using two ceramic veneers with or without coloring the core. In the experimental study, 12 disc-shaped specimens were fabricated using a manually aided design- manually aided manufactured [MAD/MAM] zirconia core [Zirkonzahn]. Two veneering ceramics of Ceram Kiss and Zirkonzahn ICE were also used to veneer the specimens. Half of the zirkonzahn discs were remained white and the others were colored by shade A2. Then, the discs were cut into microbars [30 for each group] and the microtensile bond strength of the core-veneer was calculated. The specimens were assessed using scanning electron microscopy [SEM] and the data were analyzed using two-way ANOVA and Student's t-test. Significant differences with respect to veneer layer were found [P<0.001]. No significant differences were seen among colored and uncolored cores [P=0.69]. According to the apparent effect of veneering ceramics on the core-veneer bond strength, careful selection of these agents is essential to achieve adequate bond strength between core and veneer to prevent delaminating and chipping failures of zirconia veneered restorations