Effect of Different Wall Thicknesses on Fracture Strength, Marginal Accuracy and Translucency of Monolithic Ceramic Restorations

Authors

1 Specialist at El Matarya Teaching Hospital.

2 Professor of Crowns and Bridges, Faculty of Dental Medicine for Girls Al-Azhar University

3 Assistant professor of Crowns and Bridges, Faculty of Dental Medicine for Girls Al-Azhar University

Abstract

The present study was conducted to evaluate the effect of different crown wall thicknesses (0.5mm, 1mm and 1.5mm) on the fracture load, marginal accuracy, and translucency of monolithic CAD-CAM manufactured lithium disilicate and Zirconia crowns. Materials and Methods: 60 monolithic single were constructed using CAD/CAM machine divided into two groups according to the material of construction Group (E): Monolithic IPS e.max CAD lithium disilicate crowns and Group (B): Monolithic BruxZir Solid zirconia based crowns. Each group was divided into three subgroups according to the axial wall thickness of the crown into Subgroup (0.5): 0.5 mm margin thickness, Subgroup (1): 1mm margin thickness and Subgroup (1.5): 1.5mm margin thickness. The Vertical Marginal gap was determined using Digital microscope, while translucency parameter was determined using a Spectrophotometer, then the fracture load was determined using universal testing machine and finally fracture pattern was detected by scanning electron microscope. The collected data were statistically analyzed. Results: Vertical marginal gap values for both groups (E and B) were within the acceptable clinical range. The translucency parameters (TP) values in group E revealed a higher mean value than in group B for all subgroups. The fracture load in group B revealed a higher mean value than in group E for all subgroups.
Conclusion: Increasing the wall thickness can effectively increase the fracture strength while decrease the marginal gap and translucency of the monolithic lithium disilicate ceramic crowns and zirconia crowns.

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