Background: Occlusal veneers fabricated with different materials and thicknesses
can reveal different marginal adaptation after thermodynamic aging.
Methodology: Extracted maxillary premolar teeth (n=28) were collected and
embedded in epoxy resin block with light body material then randomized according
to materials into two groups (n=14): Lithium disilicate IPS e.max CAD (A) and
Zirconia reinforced lithium silicate Celtra Duo (B) then further randomized into four
subgroups (n=7) according to occlusal veneer thicknesses 1 mm and 1.5 mm. Teeth
were prepared by a customized milling machine then the exposed dentine was
immediately sealed by dentine bonding agent. Fabrication of the occlusal veneers was
done by CAD/CAM milling machine. Occlusal veneers were adhesively cemented by
dual cure resin cement (Panavia F 2.0). All samples were subjected to thermocycling
and cyclic loading equivalent to one year of service (150,000). Marginal gap
measurements then were done with A digital microscope at 35x magnification was
used to photograph each specimen. Marginal gap was measured and evaluated using
a computerized image analysis system.
Results: two-way ANOVA showed that the materials only IPS e.max CAD
(39.30±5.14) had significantly higher value than Celtra Duo (31.52 ± 5.69) (p<0.001).
While regarding the thicknesses 1 mm thick samples (36.78 ± 6.06) had significantly
higher value than 1.5 mm thick samples (34.04 ± 7.02) (p=0.020).
Conclusion: Zirconia reinforced lithium silicate (Celtra DUO) occlusal veneers
showed better marginal adaptation than lithium disilicate (IPS e.max CAD) in
different thicknesses. Zirconia reinforced lithium silicate (Celtra DUO) marginal
adaptation was influenced by occlusal veneer thickness (the thicker 1.5 mm showed
better adaptation than 1mm.
