Relationship Between Internal Accuracy and Load-Bearing Capacity of Minimally Invasive Lithium Disilicate Occlusal Veneers

Abstract

Purpose: To test whether internal accuracy affects the load-bearing capacity of 0.5-mm-thick occlusal veneers made out of milled or heat-pressed lithium disilicate (LS2). Materials and methods: Extracted human molars (N = 80) were divided into four groups (n = 20 each) depending on the bonding substrate (enamel [E] or dentin [D]) and the fabrication method (milling [CAD] or heat pressing [PRE]) for the occlusal LS2 veneers: (1) E-CAD, (2) D-CAD, (3) E-PRE, or (4) D-PRE. After restoration fabrication, the abutment teeth and the corresponding restorations were scanned and superimposed in order to measure the marginal and internal accuracy. After adhesive cementation, the specimens were thermomechanically aged and thereafter loaded until fracture. The load-bearing capacities (Fmax) were measured. Fmax and the marginal and internal accuracy between the groups were compared using Kruskal-Wallis test (P < .05) and pairwise group comparisons. In addition, the relationship between Fmax and the internal accuracy was analyzed using Spearman rank correlation. Results: Median Fmax values (and first and third quartiles) per group were as follows:

Posterior minimally invasive full‐veneers: Effect of ceramic thicknesses, bonding substrate, and preparation designs on failure‐load and ‐mode after fatigue

“…An article reviewing preclinical studies concerning CAD/CAM occlusal veneers suggests 0.7–1.0 mm of thickness to be appropriate for LDS occlusal veneers 23 . It was additionally shown that good internal accuracy of LDS occlusal veneers increased their failure load 8 with a superior performance of pressed restorations 29 …”

“…7 An article reviewing preclinical studies concerning CAD/CAM occlusal veneers suggests 0.7-1.0 mm of thickness to be appropriate for LDS occlusal veneers. 23 It was additionally shown that good internal accuracy of LDS occlusal veneers increased their failure load 8 with a superior performance of pressed restorations. 29 However, preclinical data on premolar restorations is scarce and mostly focuses on occlusal onlays not covering the labial aspect 6,10 or describe labial veneers without covering the occlusal surface.…”

“…Regarding LDS veneer restorations, several in vitro studies investigating occlusal veneers with different ceramic thicknesses and substrates, mainly in molars, have been published. [7][8][9] In one of the studies, the occlusal ceramic thickness was reduced to 0.3-0.6 mm and restorations still revealed load-bearing capacities that are comparable to healthy teeth. 7 An article reviewing preclinical studies concerning CAD/CAM occlusal veneers suggests 0.7-1.0 mm of thickness to be appropriate for LDS occlusal veneers.…”

“…In the anterior dentition, ceramic laminate veneers have proven to be a reliable, functional, and esthetic treatment option 4 . Occlusal veneers and onlays aim to replace the lost occlusal tooth substance in the posterior region 5–12 . However, when defects additionally involve cervical areas, options are either to perform a full‐crown preparation or to add a cervical Class V resin filling to occlusal restorations.…”

“…4 Occlusal veneers and onlays aim to replace the lost occlusal tooth substance in the posterior region. [5][6][7][8][9][10][11][12] However, when defects additionally involve cervical areas, options are either to perform a full-crown preparation or to add a cervical Class V resin filling to occlusal restorations. Whereas crown preparation requires 63%-72% removal of coronal tooth structures, 13 Class V restorations reveal limited survival and impaired esthetics in the worn dentition.…”