Purpose:The purpose of this study was to evaluate the effect of sodium hypochlorite (NaOCl) as an etching agent following phosphoric acid (PA) and hydrofluoric acid (HF) etching on the fracture strength and surface roughness of lithium disilicate veneers.Materials and methods: A total of 36 lithium disilicate samples were fabricated based on inclusion criteria.The samples were divided into three groups based on the etching agent used.Group A samples were etched using 9% HF, group B samples were etched using 37% PA followed by NaOCl, and group C samples were etched using 9% HF followed by NaOCl.The surface roughness of all the samples was tested using scanning electron microscopy (SEM).All samples were subjected to a universal testing machine to assess the fracture strength.The data were analyzed by one-way ANOVA and Tukey post hoc test.Results: Samples etched with 9% HF followed by NaOCl (group C) demonstrated the highest fracture strength (120.358 26.286 N), followed by samples etched only with 9% HF (group A) (52.171 3.875 N) and samples etched with 37% PA followed by NaOCl (group B) (22.158 7.511 N).The surface roughness was maximum in group A (1.453 0.314 m) while group B showed the lowest roughness (0.356 0.258 m).One-way ANOVA showed significant differences among the groups for both fracture strength and surface roughness (p = 0.001).Tukey's post hoc test showed a significant difference between all the groups for fracture strength and surface roughness, except between group A and group C; the difference in surface roughness was insignificant (p = 1.000).Collectively, the SEM findings highlight clear morphological variation among the treatment groups, each producing a distinct pattern of surface roughness that may influence adhesive performance. Conclusion:The lithium disilicate veneers treated with HF and NaOCl achieved higher fracture strength and surface roughness with enhanced mechanical properties.Within the limitations of the in vitro design and loading condition, this combined protocol demonstrated potential to improve surface characteristics and bonding behavior.
Sundaram et al. (Thu,) studied this question.