Comparative analysis between the marginal gap of different copings

Objective: This study aims to conduct a comparative analysis between the marginal gap of copings in four different ceramic systems: metalloceramic with the use of an alternative alloy made of nickel, chromium, molybdenum and titanium (TiliteStar, Talladium USA); ceramic crown made of aluminum oxide (Procera AllCeram, NobelBiocare Sweden); and ceramic crown of zirconium oxide (Procera AllZircon, NobelBiocare Sweden) before the ceramic firing cycle, being the control group metalloceramic crown using a precious alloy of Au-Pt-Pd (DeguDent U, Dentsply USA).

Method: Forty copings were evaluated, being ten of each ceramic system: precious and non precious alloy-based metalloceramics obtained from the lost wax technique; Procera Alumina and Procera Zirconia obtained by double scanning, of the abutment and the waxing. All were built directly over a prefabricated 4.3 select abutment (Easy Abutment, NobelBiocare), with 5mm in height, with 6¢ª axial inclination and chamfer ending at 0.5mm-width.
Measurements to evaluate the marginal gap were performed in the vertical direction, using four reference points. This procedure was repeated so that each side was measured three times at each point of reference, totalizing twelve measurements in each sample. The specimens were analyzed in a profile projector (Deltronic DV 114-USA) with an increase of 20X. The groups were statistically analyzed using ANOVA and Multiple Comparison Test Newman-Keuls.

Result: Among the systems evaluated, the zirconium oxide showed the lowest average of the marginal gap, it was statistically significant for metal alloys and not significant for aluminum oxide. The aluminum oxide had a lower average marginal gap of the aura alloy (not statistically significant) and a better outcome than the Ni-Cr-Mo-Ti (statistically significant). The aura alloy obtained a lower average of marginal gap than the alternative alloy, statistically significant.

Conclusion:  All ceramic systems evaluated showed marginal gap values ​​within the clinically accepted limits described in the literature.