Assessment of Marginal Adaptation of Two CAD/CAM Glass Ceramic Occlusal Veneers at Different thickness After Thermodynamic aging

Abstract

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.

Non-Invasive Digital Technique for Examination of Marginal and Internal Adaptation of Different Ceramic Table-Tops

“…(67) Group CD table-tops fabricated from Celtra DUO, showed better marginal and internal adaptation than table-tops fabricated from e.max CAD in group ED. This result came in agreement with Ahmed et al, (74) Basheer et al, (75) , and Abuhajar et al, (42) , the microstructure of Celtra Duo, as manufacturer claims, presented increased edge stability, so offering satisfactory margins. (76) While inferior marginal and internal adaptation of e. max CAD resulted from dimension changes that happened during the crystallization firing stage as CD restorations were milled in a fully crystallized state, while ED restorations were milled in partially crystallized form.…”

“…(39) In addition, keeping a minimal cement thickness enhances the accurate insertion of the table-tops and allows insertion of an even thickness of cement layer with average values ranged from 25 to 50µm at the margin. (40) Table-tops of 1 mm thickness were applied in the present study simulating many published literature, (41,42) As a systematic review by Albelasy et al who concluded that lithium disilicate glass ceramic showed a satisfactory fracture strength results of the table-tops fabricated at a thickness of 0.7-1.0 mm. (43) Marginal adaptation is crucial as cement exposure to the oral environment leads to subsequent cement dissolution and development of secondary caries.…”

The Impact of Different Preparation Designs on Marginal Adaptation of Pressable Ceramics (An In-vitro Study)

“…The most important technical factor for long-term restoration success and enhanced prosthesis retention is marginal adaptation of fixed prosthodontics (31) . Marginally, the tissues surrounding restorations and their long-term durability are affected by design of the finish line and materials used (34) .…”

“…Each etched surface was rinsed with water spray for 60 seconds and then air dried for 20 seconds. A layer of silane coupling agent (Bisco, Company, USA) was applied for 60 seconds to the etched surface, and then air thinned (31) . Each tooth was etched using 37% phosphoric acid (Meta Biomed, Korea) and then a universal bond (Bisco, Company, USA) was applied.…”

“…Each tooth was etched using 37% phosphoric acid (Meta Biomed, Korea) and then a universal bond (Bisco, Company, USA) was applied. Dual cured self-etch and self-adhesive resin cement (Bisco, Company, USA) was then loaded into the fitting surface of each treated crown (31) . Each crown was then cemented to its corresponding prepared abutment.…”