Interfacial nanoleakage and internal cement thickness of three esthetic crown systems

To evaluate interfacial nanoleakage expression of the combination of different cementation procedures and different crown systems.

Forty-five human premolars prepared to receive single crowns were randomly divided into three groups (n=15) based on the materials to be used for crown fabrication and cementation: group 1: Zirc (Ivoclar-Vivadent) cemented with Multilink Automix; group 2: Ivoclar disilicate IPS Empress 2 luted with Excite DSC in combination with Variolink II; group 3: AAdva Zirconia (GC) cemented with G-Cem Automix. The specimens were then assessed for interfacial nanoleakage expression and the amount of silver deposits along the interface was quantified. The thickness of the cement was assessed at 5 different levels: cervical margins, midway between the cervical margin and the occlusal wall along the axial walls and at the occlusal wall. The nanoleakage scores and the cement thickness were analyzed with Kruskall-Wallis non-parametric Analysis of Variance and Dunn's Multiple-range post hoc test.

Group 2 showed significantly less nanoleakage expression than group 1 (p<0.05). The groups can be ranked in the following order 3<1<2 with regard to the cement thickness.

There was no correlation among combination of different cementation procedures and different crown systems and interfacial nanoleakage. Also the cement thickness and the degree of nanoleakage cannot be related. The amount of cement found at the cervical margins of all groups showed discrepancies within a clinical acceptable range.