IADR Abstract Archives
Evaluation of Crown Retention of CAD/CAM Hybrid Resin Ceramic Blocks
Objectives: To assess the effect of different surface treatments on mechanical crown retention of CAD/CAM hybrid resin ceramic blocks
Methods: Human molars were milled on a crown preparation device with uniform axial and occlusal reduction of 1.5-2.0mm with total occlusal convergence of 27-33°. Each tooth was individually scanned and designed on a laser scanner with a 50µm cement gap. Experimental CAD/CAM hybrid resin ceramic crown (EXP, Prismatik) were milled on a chairside mill. Restoration surfaces were treated with the following techniques; (1) micro-etched SB (SB), (2) micro-etched SB and saliva contamination (SBSC), (3) 5% HF etching (HF), (4) 5% HF etching plus silane (HFS). Optibond XTR Adhesive was then applied inside the restoration, and light-cured for 10s. Prepped dentin, either treated with (G) or without Gluma, (NG), were bonded with Optibond XTR, according to the manufacturer’s IFU. Crowns were cemented to dentin with Maxcem Elite and light-cured for 10s per marginal sides. Specimens were stored in DI water for 24hrs at 37°C. Using a pull-off method, crown retention force was measured with a Universal Testing Machine under a crosshead speed of 1mm/min. Crown retentive stress was calculated by considering retention force over contacted surface area. Data was analyzed using a two-factor ANOVA, followed by a post-hoc Tukey analysis (a=0.10).
Results: Crown retentive stress values (MPa) from non-aging condition were: 3.51±0.80 (G-SB), 4.44±1.31 (NG-SB), 3.20±1.40 (G-SBSC), 3.10±0.63 (NG-SBSC), 4.15±0.77 (G-HF), 3.85±1.68 (NG-HF), 4.19±1.75 (G-HFS), and 2.13±0.71 (NG-HFS). There was no difference between G and NG (p=0.216). Within NG-groups, SB and HF showed higher values than HFS (p=0.002 and p=0.032, respectively), but there is no difference between SB and HF (p=0.764). On the contrary, no difference was indicated for the surface treated groups with G use (p>0.10).
Conclusions: Crowns milled from the CAD/CAM hybrid resin ceramic block exhibited a promising crown retention when SB or HF were applied.
Methods: Human molars were milled on a crown preparation device with uniform axial and occlusal reduction of 1.5-2.0mm with total occlusal convergence of 27-33°. Each tooth was individually scanned and designed on a laser scanner with a 50µm cement gap. Experimental CAD/CAM hybrid resin ceramic crown (EXP, Prismatik) were milled on a chairside mill. Restoration surfaces were treated with the following techniques; (1) micro-etched SB (SB), (2) micro-etched SB and saliva contamination (SBSC), (3) 5% HF etching (HF), (4) 5% HF etching plus silane (HFS). Optibond XTR Adhesive was then applied inside the restoration, and light-cured for 10s. Prepped dentin, either treated with (G) or without Gluma, (NG), were bonded with Optibond XTR, according to the manufacturer’s IFU. Crowns were cemented to dentin with Maxcem Elite and light-cured for 10s per marginal sides. Specimens were stored in DI water for 24hrs at 37°C. Using a pull-off method, crown retention force was measured with a Universal Testing Machine under a crosshead speed of 1mm/min. Crown retentive stress was calculated by considering retention force over contacted surface area. Data was analyzed using a two-factor ANOVA, followed by a post-hoc Tukey analysis (a=0.10).
Results: Crown retentive stress values (MPa) from non-aging condition were: 3.51±0.80 (G-SB), 4.44±1.31 (NG-SB), 3.20±1.40 (G-SBSC), 3.10±0.63 (NG-SBSC), 4.15±0.77 (G-HF), 3.85±1.68 (NG-HF), 4.19±1.75 (G-HFS), and 2.13±0.71 (NG-HFS). There was no difference between G and NG (p=0.216). Within NG-groups, SB and HF showed higher values than HFS (p=0.002 and p=0.032, respectively), but there is no difference between SB and HF (p=0.764). On the contrary, no difference was indicated for the surface treated groups with G use (p>0.10).
Conclusions: Crowns milled from the CAD/CAM hybrid resin ceramic block exhibited a promising crown retention when SB or HF were applied.