Effects of the Presence of Adjacent Tooth and Material Type on the Marginal and Internal Adaptation of Endocrowns Fabricated by the Digital Impression Technique

Purpose

To assess the effects of the presence of adjacent tooth and material type on the marginal and internal adaptation of endocrowns fabricated by the digital impression technique.

Material and Methods

An endodontically treated molar tooth was used for the fabrication of endocrowns in this in vitro study. Five groups of specimens (n = 17) were evaluated based on the material type and presence of adjacent tooth: three groups of monolithic zirconia (Zir), lithium disilicate (LDS), and zirconia-reinforced lithium silicate (ZLS) in the presence of adjacent teeth, and two groups of zirconia endocrowns, one in the absence of an adjacent anterior tooth (second premolar; Zir-no ant.) and one in the absence of a posterior adjacent tooth (second molar; Zir-no post.). Marginal and internal adaptation of endocrowns was evaluated by the silicone replica technique. Data were analyzed by ANOVA with Tukey test for pairwise comparisons and generalized estimating equation with Bonferroni correction for pairwise comparisons (α = 0.05).

Results

The largest marginal gap was found in the ZLS, followed by the LDS and Zir groups (p < 0.05). The Zir group showed significantly higher internal adaptation than the ZLS group (p < 0.05); LDS had no significant difference with the ZLS and Zir groups (p > 0.05). The Zir group showed larger marginal and internal gaps than the Zir-no ant. and Zir-no post. groups (p < 0.05); the latter two groups had no significant difference (p > 0.05). All groups showed the largest gap at the pulpal and the smallest gap at the marginal and cervical areas (p < 0.05).

Conclusion

Zirconia endocrowns showed the highest marginal and internal adaptation. Digital impression technique in absence of anterior or posterior adjacent tooth would result in higher marginal and internal adaptation of endocrowns.