Fracture resistance of veneers in premolars

Abstract

Objective:The purpose of the study was to compare the fracture resistance of ceramic veneers and composite resin veneers with and without dental preparation.Materials and Methods:Forty freshly extracted mandibular premolars were selected and randomly assigned into four groups (n = 10): 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, and the thickness of this area was the same of the buccal area (0.2 mm or 0.5 mm). After the luting procedure, all groups were thermocycled (10,000 cycles, 5°C–55°C) and subjected to fracture resistance test under compression (Instron 4444 with a crosshead speed of 0.5 mm/min). The mode of failure analysis was performed under a ×10 magnification. Data were subjected to one-way ANOVA and Duncan's post hoc test (P < 0.05).Results:The mean fracture resistance (men ± standard deviation) was NPR = 690.33 ± 233, NPC = 790.52 ± 408, P2C = 1131.34 ± 341, and P5C = 983.56 ± 202. There were significant differences of the fracture resistance values between all groups (P = 0.013). NPR and NPC groups showed mean values of fracture resistance significantly lower than P2C. However, 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%).Conclusion:Minimally invasive tooth preparation (0.2-mm) allowed to achieve higher fracture resistance in premolars restored with lithium disilicate ceramic veneers. Attention should be given to the 0.5 mm preparation since catastrophic fractures only happened when this preparation depth was performed.

Management of Discolored Failure Root Canal-Treated Upper Lateral Incisor

“…Nonvital internal bleaching was first constructed for the tooth to achieve acceptable color appearance before proceeding with the indirect full veneer restoration. E-max veneers were chosen since they are made up of porcelain which is highly resistant to stain and only minimal enamel reduction is needed to fit a 0.3 mm thickness of the material [14,15].…”

Evaluation of the fracture strength of porcelain sectional veneers made from different sintered feldspathic porcelains: An in vitro study

“…However, 1 study found that minimally invasive tooth preparation (0.2 mm) allowed higher fracture resistance in the case of restorations with lithium disilicate ceramic veneers. 34 Another study compared the fracture strength and other properties of the veneers fabricated using different techniques and materials, and concluded that there were fewer marginal discrepancies with feldsphatic porcelain and that the fracture strength decreased when more covering to the dental tissue was applied. 24 Yet another study showed that more preparation for the dental tissue could be associated with a decreased shear strength of lithium disilicate laminate veneers.…”

“…6). A possible reason for this could be that the load was high enough to exceed the proportional limit of the tooth, [33][34][35][36][37][38][39] especially in the teeth with thin roots. In general, extracted human teeth vary in quality and standardizing this factor is difficult.…”

Resin Gingival Barrier as a Polymerizable Try-In Paste for Dynamic Try-In of Crowns and Veneers

“…It is reported in the literature that surface microcracks will cause significant decrease in the strength of ceramic veneers, and therefore it is recommended that all bite adjustments to be performed during the try-in session to allow for a final laboratory glaze fire. 3 Try-in pastes are fabricated with the primary concern that the optical properties of the paste should be identical to those of the cement. The viscosity and adherence power during the cementation are not given adequate attention by companies and the commercially available products are "water-runny" try-in pastes.…”