Influence of ceramic thickness and dental substrate on the survival rate and failure load of non‐retentive occlusal veneers after fatigue

Abstract

ObjectiveTo investigate the effect of ceramic thickness and dental substrate (enamel vs. dentin/enamel) on the survival rate and failure load of non‐retentive occlusal veneers.Materials and MethodsHuman maxillary molars (n = 60) were divided into five test‐groups (n = 12). The groups (named DE‐1.5, DE‐1.0, DE‐0.5, E‐1.0, E‐0.5) differed in their dental substrate (E = enamel, DE = dentin/enamel) and restoration thickness (standard: 1.5 mm, thin: 1.0 mm, ultrathin: 0.5 mm). All teeth were prepared for non‐retentive monolithic lithium‐disilicate occlusal veneers (IPS e.max Press, Ivoclar). Restorations were adhesively cemented (Syntac Classic/Variolink II, Ivoclar) and exposed to thermomechanical fatigue (1.2 million cycles, 1.6 Hz, 49 N/ 5–55°C). Single load to failure was performed using a universal testing‐machine. A linear‐regression model was applied, pairwise comparisons used the Student–Newman–Keuls method (p < 0.05).ResultsThree dentin‐based occlusal veneers (one DE‐1.0, two DE‐0.5) revealed cracks after fatigue exposure, which corresponds to an overall‐survival rate of 95%. Load to failure resulted in the following ranking: 2142 N(DE‐0.5) > 2105 N(E‐1.0) > 2075 N(E‐0.5) > 1440 N(DE‐1.5) > 1430 N(DE‐1.0). Thin (E‐1.0) and ultrathin enamel‐based occlusal veneers (E‐0.5) revealed high failure loads and surpassed the standard thickness dentin‐based veneers (DE‐1.5) significantly (p = 0.044, p = 0.022).ConclusionAll tested monolithic lithium disilicate occlusal veneers obtained failure loads above physiological chewing forces. Thin and ultrathin enamel‐based occlusal veneers outperformed the standard thick dentin‐based occlusal veneers.Clinical SignificanceMinimally invasive enamel‐based occlusal veneer restorations with non‐retentive preparation design may serve as a conservative treatment option.

Minimally invasive CAD/CAM lithium disilicate partial‐coverage restorations show superior in‐vitro fatigue performance than single crowns

“…function and therefore subjected to single load to failure testing as in previous studies. 24,50,62,63 So far, neither clinical studies nor laboratory investigations could show that pre-damaged reconstructions exhibit a shorter service life or failure loads than non-damaged restorations. 29,48,63 A possible explanation might be that resulting cracks, depending on their locations, may require much larger driving forces to propagate across an anatomic restoration.…”

“…In contrast, minimally invasive LDS occlusal veneers (IPS e.max Press and IPS e.max CAD) showed extraordinary results in a systematic review on in-vitro and clinical studies. 15,[48][49][50] Nevertheless, clear recommendations for a minimally invasive preparation design for cases in which defects involve occlusal as well as buccal or cervical areas are currently missing. Therefore, the aim of this in-vitro study was to evaluate the fatigue survival and failure load of CAD/CAM fabricated LDS standard (1.5 mm), thin (1.0 mm), and ultrathin (0.5 mm) PCRs compared to crowns on molars after thermomechanical loading.…”

Effects of Ceramic Translucency and Thickness on Polymerization of a Photosensitive Resin Cement

“…However, there are several factors that affect overall success [6], and the cementation procedure is one such factor, directly affecting fatigue resistance and retention [7][8][9]. The adhesion of ceramic restorations to the tooth structure is a critical step that affects longevity and success of treatment.…”

“…The adhesion of ceramic restorations to the tooth structure is a critical step that affects longevity and success of treatment. A strong, durable bond achieved with well-polymerized resin cement provides high retention, improved marginal adaptation and increased ceramic fracture resistance [7]. Insufficient polymerization has been associated with microleakage, recurrent caries, post-operative sensitivity, discoloration and decreased mechanical properties [10].…”

“…Oral 2023, 3 Resin cements have been classified into different categories depending on their adhesive procedures and chemical components [7]. One type of classification is according to the mode of polymerization, chemical cure, light cure and dual cure.…”