KHẢO SÁT HÌNH THÁI GÃY VỠ MẶT DÁN SỨ ZIRCONIA VÀ LITHIUM DISILICATE

Abstract

Objective:This study aimed to investigate the fracture morphology of zirconia and lithium disilicate ceramic veneers (CVs) fabricated using a digital workflow. Materials and Methods:
Forty maxillary central incisors on typodont models were prepared with two finish line designs: feathered-edge (FE) and palatal chamfer (PC). Multilayer zirconia (Z) and lithium disilicate (L) veneers were fabricated and divided into four groups: ZFE, LFE, ZPC, and LPC (n = 10 per group). All veneers were bonded using resin cement, following the manufacturer's instructions. Each specimen underwent axial compressive loading at a crosshead speed of 1.0 mm/min, using a universal testing machine. The data were analyzed using Fisher’s exact test to compare the fracture morphologies among the experimental groups. Results: Within the same finish line design, there was no statistically significant difference in fracture morphology between zirconia and lithium disilicate veneers (p > 0.05). However, within the same ceramic material, significant differences in fracture patterns were observed between the two preparation designs (p < 0.05). The PC design was primarily associated with ceramic fractures, whereas the FE design commonly showed adhesive failures or mixed failures involving both ceramic fracture and debonding. Zirconia veneers demonstrated fewer ceramic fractures but a higher tendency for debonding compared to lithium disilicate veneers (p > 0.05). Conclusion: Incisal design significantly influenced the fracture morphology of veneers. PC design was mainly associated with cohesive fractures, whereas FE design often resulted in adhesive or mixed failures. Zirconia fractured less but showed a higher tendency for debonding compared to lithium disilicate.