The Influence Of Thermocycling On The Marginal adaptation Of Different Glass Ceramic Sectional Veneers

Abstract

Background: Sectional veneers constructed from different glass ceramic can show variations in the marginal adaptation before and after thermocycling. Methodology: 20 human central incisors were used to fabricate sectional laminate veneers SLV with preparation depth 0.5mm cervically and 0.7mm incisally. Samples were divided equally into groups according to material Group 1: Lithium disilicate Glass-Ceramic (IPS e-max press, Ivoclar, Schaan Liechtenstein) (n=10) and Group 2: zirconia reinforced lithium silicate Glass-Ceramic (Celtra Press, Dentsply Sirona) (n=10). SLV were bonded to the teeth using lightcure resin cement (Relyx veneer) (3M ESPE, Seefeld, Bayern, Germany). The samples were then subjected to 10,000 thermal cycles, the marginal adaptation was measured before and after thermocycling using stereomicroscope under magnification 40X using 8 measurement points for each margin (incisal, proximal, cervical and mid labial in two different positions) with total of 40 point per sample. Results: The results of ANOVA showed a significant interaction between material and thermocycling. Before thermocycling, e.max samples showed statistically significant higher gap values with (p<0.001) Mean and standard deviation (SD) values (34.80±0.71) than Celtra samples with (p<0.001) (26.33±2.28). While after thermocyling, Celtra samples had significantly higher gap values (53.77±6.67) than e.max samples (42.81±1.67). Conclusions: IPS e.max Press SLV showed better marginal adaptation compared to that of Celtra Press after thermocycling. Insufficient sealing between restoration and tooth may lead to leakage and marginal discoloration in sectional veneers after years of service.