Mechanical Behavior of Thin Ceramic Laminates on Central Incisors

Restorative dentistry often uses ceramic laminate veneers for aesthetic anterior teeth restorations due to their natural appearance and minimal invasiveness. However, the understanding of their clinical performance and how ceramic microstructure and processing affect longevity is limited. This study aimed to address this gap by determining the mechanical behavior, fracture load, and failure modes of CAD-CAM processed laminate veneers made of either lithium-disilicate-based glass ceramic (IPS e.max CAD) or feldspathic porcelain (Vita Mark II). It also aimed to develop a mechanical cycling methodology capable of determining the lifetime and failure modes of thin ceramic laminate veneers. Eighteen human maxillary central incisors were used to create the specimens. Minimal enamel preparation was required to ensure the proper adaptation of the thin ceramic laminates. Ceramic laminates made from lithium disilicate and feldspathic porcelain (Vita Mark II) were produced via CAD-CAM, with the final thicknesses less than 0.5 mm, then cemented with resin cement. The mean fracture load for the glass ceramic was 431.8 ± 217.9 N, while for the porcelain, it was 454.4 ± 72.1 N. Failure modes differed considerably: porcelain showed more chipping, while lithium disilicate was associated with tooth structure failure. The material used did not significantly affect the fracture load of thin ceramic laminates in static tests. However, failure modes differed considerably. It was not possible to determine a set of mechanical cycling parameters that could establish the fatigue properties of thin ceramic laminates, as the maximum number of cycles reached was 536,818.