Minimally invasive tooth preparation allowed achievement of a higher fracture resistance of lithium disilicate ceramic veneers.

Linhares LA, Pottmaier LF, Lopes GC. Eur J Dent 2018; 12: 191–198.

This study compared the fracture resistance of ceramic veneers and composite resin veneers with and without dental preparation. Forty freshly extracted mandibular premolars were selected and randomly assigned into four groups. Group NPR = no dental preparation and direct veneer with 0.2 mm thick composite resin (Amelogen Plus, Ultradent); Group NPC = no dental preparation and 0.2 mm thick lithium disilicate ceramic veneer (IPS e.max Press, Ivoclar Vivadent); Group P2C = tooth preparation of 0.2 mm and 0.2 mm-thick ceramic veneer (IPS e.max Press); and Group P5C = tooth preparation of 0.5 mm and 0.5 mm-thick ceramic veneer (IPS e.max Press). In all groups, the restorations covered 1 mm of the occlusal surface of the buccal cusp. After luting, all groups were thermocycled and subjected to fracture resistance tests under compression. There were significant differences of the fracture resistance values between all groups. NPR and NPC groups showed mean values of fracture resistance significantly lower than P2C. P5C presented intermediate values without a significant difference from the other groups. The mode of failure for all groups was mixed (60%), cohesive failures (20%), root failures (15%), and adhesive failures (5%).