Effect of Abutment Preparation Designs Influencing Retention in Short Clinical Crowns Receiving All-ceramic Complete Veneer Restoration

dislodging forces, when all other features of retention are accomplished in the tooth preparation. 11This problem of decreased height of the clinical crowns is amplified in conditions like amelogenesis imperfecta, dentinogenesis imperfecta, dentin dysplasia, bruxism, physiological attrition, enamel hypoplasia, congenital microdontia, and regressive alterations in teeth.Reduced height of the abutments has always posed great challenges to clinicians achieving retention in complete veneer IntroductIonDespite the marked clinical performance and success rate, there are a few limitations that compromise the success of complete veneer restorations. 1One of the serious problems associated with failure in fixed restoration is retention, characterized by dislodgement of the restoration. 1,2There are several factors contributing to this phenomenon, such as compromised height of the abutments, preparation geometry, caries, salivary contamination of luting cements during cementation, dissolution of luting cements by saliva and gingival crevicular fluid, electrolytic corrosion, partial or complete abutment fracture, magnitude of dislodging forces, and types of occlusal rehabilitation schemes. 3,4he taper and geometry of the tooth preparation, the height of abutments, the surface area of the tooth involved, the degree of dislodging forces, occlusal stress, and luting agents are the most important elements affecting retention.The taper of the tooth preparation has a significant impact on retention. 5The amount of taper required for clinically optimal retention ranges from 6 to 20, according to accepted criteria.Numerous studies have shown that as the taper angle in the preparation increases, the amount of retention decreases. [6][7][8][9][10] Height of the abutments is an important skewing factor jeopardizing retention in complete veneer restoration against 1-