Fracture load of CAD/CAM ultrathin occlusal veneers luted to enamel or dentin

Abstract

Objectives To evaluate, in vitro, the fracture load of IPS e.max CAD occlusal veneers at thicknesses of either 0.3 or 0.6 mm luted to enamel or dentin. Materials and methods Fifty human molars were randomly distributed into five groups (n = 10): G1 ‐ healthy teeth (control); G2‐0.3‐mm‐thick veneers luted to enamel; G3‐0.6‐mm‐thick veneers luted to enamel; G4‐0.3‐mm‐thick veneers luted to dentin; and G5‐0.6‐mm‐thick veneers luted to dentin. After the luting procedures, the specimens were immersed in distilled water at 37°C for 24 hours and then subjected to mechanical loading (106 cycles at 200 N load). The specimens were subjected to a fracture load test in a universal testing machine. Two‐way ANOVA and Tukey's test (α = 0.05) were used to analyze data. Results Only the thickness factor was significant (P = .002). Values of fracture load followed by distinct letters represent significant differences (P < .05): G1 (3204 N ± 730)ab; G2 (3144 N ± 729)ab; G3 (2489 N ± 606)b; G4 (3591 N ± 776)a; and G5 (2770 N ± 598)ab. Conclusion IPS e.max ultrathin occlusal veneers luted to enamel or dentin obtained fracture load comparable to that of the healthy tooth. Clinical significance IPS e.max CAD ultrathin occlusal veneers at 0.3 or 0.6‐mm‐thick seem to provide good perspectives in relation to the clinical use.

Fracture Resistance and Failure Mode of Occlusal Veneer Restorations: Effect of Material Type and Bonded Substrate

“…17 There was no statistical significant difference between the tested substrates. This comes in accordance to Valenzuela et al (2020) 18 19 in which fracture resistance of lithium disilicate occlusal veneers with a class I cavity was higher than fracture resistance of restorations where a composite filling in the class I dentin cavity. These findings have shown that the restoration of a tooth with a lithium disilicate ceramic material does not require composite in the cavity preparation of the class I with the cavity design optimization approach.…”

Fracture Resistance and Failure Mode of Mandibular Molar Restored by Occlusal Veneer: Effect of Material Type and Dental Bonding Surface

“…With occlusal veneers, the dental bonding surfaces can vary greatly, and may be purely enamel, dentin, or composite fillings, and each of these bonding substrates could affect the fracture resistance differently [34,38,39]. The strength of tooth-restoration complex is influenced by the elastic moduli of the material and substrate, as well as the material's flexural resistance [40,41].…”

Effect of Different Bonding Substrates on Fracture Resistance of Thin and Ultra-thin Occlusal Veneers constructed using Different CAD/CAM Materials

“…These results may be attributed to the greater flexibility that was given to the ceramic network of the hybrid ceramics after being infiltrated with polymers which lessens the crack propagation property that was recorded as a common problem with the ceramic materials. (61,62) Many previous studies had explained the importance of the slight mismatch of the modulus of elasticity between the restoration and the supporting tissues or substrates (3,17,51,63) and its positive effect on the fracture strength of these restorations. Restorative materials that better matches the modulus of elasticity of enamel or dentin gives better stress distribution and hence better fracture resistance values.…”

“…They correlate the improved fracture resistance values of the samples bonded with selective etching technique to the stability of the adhesively bonded occlusal veneers in the enamel marginal area. (59) Valenzuela et al (3) studied the effect of reduction of the occlusal veneer thickness on fracture resistance of glass ceramics. They obtained higher fracture strength values for occlusal veneers with 0.3mm thickness than that with 0.6mm thickness regardless of the bonding substrate and they linked their results to the successful adhesive bonding.…”

“…(1) Occlusal surfaces of premolars and molars may suffer from dental erosion while its progression goes on slowly and the diagnosis is obscure as well. (2,3) The extent of tooth wear plays an important role in achieving the appropriate treatment decision. (4,5) The extent of mutilation of the eroded worn dentition is irregular and may involve enamel only, enamel and minor part of dentin or enormous part of dentin with or without enamel margin.…”