Objectives: The aim of the current study was to compare the accuracy of different restorative materials currently used in porcelain laminate veneers (PLV) fabrication, in terms of external and internal adaptation, and to evaluate the longevity of the PLV seal in response to thermocycling, in terms of microleakage.
Methods: 30 (PLV) preparations were performed on maxillary central incisor to be restored with restorations fabricated by milling ceramic blocks using a CAD/CAM system. Samples were divided randomly into three groups (n=10) according to the restorative material ([Prettau, Zirkonzahn, Pustertal, Italy], [IPS e.max CAD, Ivoclar, Schaan, Liechtenstein] and VITA SUPRINITY, VITA Zahnfabrik, Bad Sackingen, Germany]). The veneers were cemented using total-etch resin cement according to manufacturer instructions, then subjected to artificial aging program after which they were immersed in basic fuchsine dye for 24 hours. All specimens were sectioned in labio-lingual direction using a precision cutting machine, and vertical gap distance, internal adaptation, and dye penetration were measured using stereomicroscope. Data were statistically-analyzed using one-way ANOVA, two-way ANOVA, Tukey's post-hoc and Student t-tests (P≤0.05).
Results: The highest statistically significant marginal gap distance and lowest internal adaptation values were recorded with Prettau group followed by IPS e.max CAD group while the lowest statistically significant marginal gap distance and highest internal adaptation values were for VITA SUPRINITY group. For the microleakage, the highest statistically significant leakage values were recorded with IPS e.max CAD group followed by Prettau group. The lowest statistically significant leakage values were for VITA SUPRINITY group. Irrespective of material's group, it was found that incisal margin recorded statistically significant higher marginal gap distance mean values than cervical one. For the microleakage, the reverse was found.
Conclusions: Under the test conditions, the following could be concluded: 1. All ceramic materials used in this study were within the clinically acceptable range of marginal accuracy. 2. CAD/CAM technology does not necessarily present highly accurate restorations, in terms of external and internal adaptation. 3. Lithium disilicate-based restorations showed better external and internal adaptation, and microleakage than monolithic Zirconia-based restorations. 4. The correlation between external and internal adaptation and microleakage is still questionable.