Objective: The objective of this in-vitro study was to investigate the effect of sintering time on the marginal and internal fits of monolithic zirconia crowns.
Method: For this study, 60 monolithic mandibular first molar crowns were fabricated from LAVA Plus, CEREC, and KATANA Y-TZP semi-sintered blocks over 4-mm highly cemented implant abutment analogs. The samples were divided into groups according to brand [n = 3] and sintering time [n = 2]. Bilateral analysis of variance was used to examine the effects of sintering time and brand on marginal and internal spacing simultaneously.
Results: In samples treated with a long sintering time, no significant difference in total cement film thickness was observed among brands. In crowns produced from CEREC and LAVA blocks, marginal spacing was not affected significantly by the sintering time [p > 0.0001]. In crowns produced from KATANA blocks, shortening of the sintering time caused a significant increase in marginal spacing [p < 0.0001].
Conclusions: We emphasize the need to apply the manufacturer-recommended sintering time.
Lava, CEREC, KATANA, cement spacing, sintering
