The Role of Preparation Geometry in Ceramic Veneers: A Comprehensive Literature Review

Abstract

Background: Ceramic veneers are regarded as a conservative and esthetically favorable treatment modality for anterior teeth, particularly when tooth structure preservation is prioritized. Among the critical variables influencing their clinical performance, the preparation design—specifically the inclusion or omission of a cervical finish line—remains a subject of ongoing investigation. Objectives: This narrative review aimed to evaluate the impact of preparation design on fracture resistance, marginal adaptation, and long-term survival of ceramic veneers. Methods: A targeted literature search was conducted across PubMed, Scopus, and Web of Science for English-language publications from 2000 to 2024 using the terms “ceramic veneers,” “preparation design,” and “finish line.” Inclusion criteria focused on in vitro and in vivo studies comparing at least two preparation designs with reported clinical outcomes, while case reports, reviews, and non-comparative studies were excluded. Of the 379 initially retrieved records, 28 studies met the inclusion criteria. Results: Findings revealed that preparations incorporating a defined finish line, such as a shoulder or chamfer, consistently demonstrated superior marginal adaptation and biomechanical stability, particularly under functional stress. In contrast, shoulderless and ultra-conservative designs preserved greater enamel substrate, which contributed to effective bonding and comparable survival outcomes in non-load-bearing regions. Across studies, ceramic veneers exhibited a mean 5- to 7-year survival rate exceeding 95%, irrespective of preparation design, provided that proper adhesive protocols were followed. Conclusion: These results support a case-by-case approach guided by the principles of minimally invasive dentistry, emphasizing enamel preservation without compromising mechanical performance. A key limitation of this review is the absence of a pre-registered protocol, which should be addressed in future systematic evaluations.