Cement Thickness of CAD/ CAM Zirconia Laminate Veneers: Impact of Preparation Design.

INTRODUCTION: This study assessed cement thickness of three veneer preparation designs: feather edge, shoulder, and shoulder with wings. OBJECTIVES: The aim was to evaluate whether the modified shoulder with wings design produced a similar cement thickness compared to the traditional shoulder and feather edge designs. METHODS: The study measured vertical, horizontal, and overall cement thickness of 60 veneer cemented (20 per group) on typodont teeth. Ceramic veneers were fabricated using CAD/CAM with each veneer assessed for fit before cementation. Ten specimens were cut vertically, and 10 were cut horizontally in each group. The cement thickness was measured for each cross-section with scanning electron microscopy. Descriptive data analysis and hypothesis testing were conducted using the nonparametric Kruskal Wallis test (alpha=.05). RESULTS: In vertical dimension, shoulder with wings design showed the smallest cement thickness. When comparing horizontal and overall cement thickness, the shoulder and shoulder with wings designs were similar. Both shoulder designs produced less overall cement thickness than the feather edge design. CONCLUSIONS: Shoulder with wings preparation produced the thinnest cement layer in vertical dimension and a comparable overall cement thickness to the shoulder design. CLINICAL RELEVANCE: Modified shoulder with wings could enhance veneer longevity by reducing vertical cement thickness.