Intervention
carious lesions, ΔE, Oxiguard II, tooth, Axis
ROBINSON
All participant underwent clinical, radiographic evaluation of all cases with shade selection using Vita System 3-D Master (VITA) was performed. During the preparatory visit, any carious lesions were removed and restored using a core build-up restorative material (GC Fuji lining LC; GC Corp, Tokyo, Japan) upon requirements. All teeth were prepared in a standardized reduction parameters following the manufacturer’s recommendations with a deep chamfer finish line, 1–1.5 mm occlusal reduction and 0.8–1.5 mm axial reduction. Astringent retraction paste (VOCO GmbH) was used into sulcus prior to digital impression.CEREC, Dentsply Sirona was used to scan and construct the entire crowns in current study. An intra-oral impression was captured using a powder-free intraoral scanner CEREC Omnicam (Dentsply Sirona) following the manufacturer’s recommendations. The prepared tooth, opposing teeth and interocclusal relationship was recorded and the biogeneric individual design mode of CAD software was used for the design. CEREC MCXL milling machine (Dentsply Sirona) was used for CAM fabrication of both groups. Checking of all crowns for proper fit with adjustments to occlusal and proximal contacts were made followed by final finishing with NTI CeraGlaze (Axis, Coppell) on an electric handpiece while following the manufacturer’s instructions at 10,000 rpm for 10 s with a fine finishing wheel and at 5,000 rpm for 10 s with a high-shine polishing wheel.At delivery visit, all prepared teeth followed same protocol for cementation. All prepared teeth were cleaned using Pumice and Robinson brush before isolated with rubber dam. Phosphoric acid etchant 37% was applied for 20 s, washed and air dried & bonding agent was applied. The fitting surfaces of all crowns were etched 60 s using 5% hydrofluoric acid according to the manufacturer’s instructions. The etched surfaces were thoroughly water sprayed and oil-free dried before application of silane coupling agent for 60 s. Dual-cure resin cement (Vriolink Esthetic, Ivoclar Viadent AG, Schaan, Liechtenstein) was used. Using a sharp explorer, extra cement was scraped off. Air-blocking gel (Oxiguard II: Kuraray Noritake Dental Inc.: Tokyo, Japan) was finally applied and light-cured (Elipar Deepcure-S: 3 M Espe: St. Paul, USA) about 20 s.A spectrophotometer (VITA Easy-shade Advance 4.0, VITA Zahnfabrik, Bad Säckingen, Germany) was used to assess the color of all participants at the follow-up appointments (baseline = 24 h after cementation, 6 months and 12 months). It was calibrated before each measurement. CIELAB parameters (L*, a*, b*) were recorded in at each follow-up appointment with the same operator who was blinded. L* indicated the material lightness, a* denotes hues change across the red-green axis, while b* showed the hues difference across the yellow-blue axis. Finally, ΔL*, Δa*, Δb*and ΔE were calculated for 6, 12 month and finally the overall color changes over the year. CIELAB (ΔE