Objectives: The aim of the study was to evaluate the marginal fit and fracture resistance after thermomechanical fatigue of two types of glass ceramic occlusal veneers constructed using two techniques for wax pattern.
Methods: Thirty-two non-carious maxillary molars were used in this study. Teeth were prepared to receive all ceramic occlusal veneers. Prepared teeth were randomly divided into two equal groups according to the fabrication material of the occlusal veneer: Group I (e-max): pressable lithium disilicate glass ceramics. Group II (Celtra): pressable zirconia-reinforced lithium silicate glass ceramics. Each group was further subdivided into two equal subgroups according to the technique of construction of the wax pattern: Subgroup A (CAD/CAM): CAD/CAM technique. Subgroup B (Conventional): Conventional technique. Wax patterns were sprued, invested and heat pressed to produce the two types of ceramic occlusal veneers. All occlusal veneers were cemented to their corresponding teeth using adhesive resin cement. Thermomechanical aging was performed on all the samples. Vertical marginal gap distance measurement and fracture resistance testing were done.
Results: The results of this study revealed that e.max (Conventional) recorded the highest vertical marginal gap mean values followed by Celtra (Conventional) then Celtra (CAD/CAM) while e.max (CAD/CAM) recorded the lowest mean values. It was found that e.max (conventional) recorded the highest fracture resistance mean values followed by Celtra (conventional) then e.max processed by (CAD/CAM) while Celtra processed by (CAD/CAM) recorded the lowest mean values.
Conclusions: CAD/CAM constructed wax pattern presents a viable alternative option to conventional wax pattern. Celtra Press material revealed promising results.