Marginal Adaptation and Fracture Resistance of Lithium Disilicate Laminate Veneers on Teeth with Different Preparation Depths

Abstract

The purpose of this study was to evaluate the marginal adaptation and fracture load of ceramic laminate veneers on teeth with different preparation depths. A total of 75 extracted intact human maxillary central incisors were prepared with three different preparation depths (P) and assigned to the following five groups (n = 15): P1 (0.3-mm depth of preparation; preparation entirely in enamel); P2 (0.5-mm depth of preparation; preparation in enamel and dentin complex); P3 (1-mm depth of preparation; preparation entirely in dentin); P4 (no preparation, only surface roughening); and P5 (unrestored, intact teeth as control). A total of 60 lithium disilicate laminate veneers were fabricated. The marginal adaptation of the veneers was evaluated by light microscope and scanning electron microscope after cementation with resin cement. Finally, the veneers were loaded until fracture at a 90-degree angle to the lingual surface of the tooth. Statistical analyses were performed using analysis of variance and Tukey multiple range test. There was a significant difference between the marginal gap value of the distocervical measurement points of P1 and P2 and the distal measurement points of P3 and P4 (P = .33 and P = .017, respectively). The highest fracture resistance values were observed in the P5 group (mean: 389.55 ± 22 N) and the P2 group (mean: 322.86 ± 79.38 N), and the lowest values were observed in the P3 group (mean: 219.21 ± 60.74 N). The marginal adaptation of the laminate veneer restorations was not related to the depth of preparation. Mean fracture resistance of laminate veneers with 0.5-mm preparation depth was greater than that of the 0.3-mm and 1-mm preparation depth laminate veneers and those with no preparation.

Marginal discrepancy and load to fracture of monolithic zirconia laminate veneers: The effect of preparation design and sintering protocol

“…In the current investigation, natural teeth were used to furnish a more clinically pertinent substrate with respect to preparation design, bonding protocol, and adhesive cementation that could affect the marginal fit and load to fracture values of monolithic zirconia laminate veneers 33,35) .…”

“…2). Each site was measured three times, and a mean value was calculated [33][34][35] . By calculating the mean values of the measurement areas in this manner, the total mean of incisal, axial, and marginal discrepancy values were recorded.…”

“…The load to fracture values were evaluated using a universal testing machine (AG-5 kNG, Shimadzu, Kyoto, Japan) equipped with a 1-kN load cell. The load was oriented at a 90-degree angle to the palatal aspect of the tooth using specially designed mounting jig [35][36][37] (Fig. 3).…”

Partial ceramic crowns. Esthetic and tissue conservative restorations – Part II: anterior teeth – Laminate Veneers

“…Therefore, if such a preparation design is chosen, ceramic thickness at the palatinal site should be increased (for leucitereinforced glass ceramic) to more than 0.5 mm. In vitro studies have also shown that the fracture resistance of laminate veneers with 0.5-mm preparation depth was greater than that of the 0.3-mm and 1-mm preparation depth [25], which, however, for the 1 mm thickness may have been due to the fact that the preparation mainly exposed dentin. It is generally accepted that the preparation should be kept -as much as clinically possible -to the enamel as bonding substrate and over-contour of the veneer should be avoided.…”

Multidisciplinary Dentistry - Ceramic Laminate Veneers for Orthodontic Finalization - Clinical Case Report

“…Changes in color and/or position of the anterior teeth may be limiting factors of this approach, often needing greater dental wearing and thicker crowns for adequate solutions 3 . The stability of color and marginal adaptation are essential to a successful esthetic rehabilitation 4 , favorable results in terms of marginal adaptation of ultra thin laminates are described in literature 5 .…”