Samah Saker1, Walid Al-Zordk1, Mutlu Özcan2. 1. Fixed Prosthodontics Department, Faculty of Dentistry, Mansoura University, Mansoura, Egypt. 2. University of Zurich, Center of Dental Medicine, Division of Dental Biomaterials, Clinic for Reconstructive Dentistry, Zurich, Switzerland.
Abstract
OBJECTIVE: The aim of this study was to assess the impact of implant platform diameters on ultimate force to failure of zirconia abutments with different angulation. MATERIALS AND METHODS: Forty-two zirconia abutments with either 0 degree (ST) or 15-degree (AN) angulation were assembled on tapered internal connection titanium implants (Direct's Legacy; 13 mm Implant Direct, LLC, Las Vegas, United States) with a platform diameter of Ø3.0, Ø3.5, and Ø4.5 mm (14 per group). Zirconia crowns (Ceramill Zolid; Amann Girrbach GmbH) were fabricated and cemented using self-adhesive resin cement (MaxCem Elite, Kerr). The specimens were thermomechanically loaded (TCML= 6,000 cycles of 5 to 50°C for 2 minutes/cycle followed by cyclic loading 600,000 cycles) followed by static loading until fracture. The data of load (N) at which fracture occurred were statistically analyzed by using Kruskal-Wallis analysis of variance and Mann-Whitney U tests at 5% significance level. RESULTS: Higher load to fracture was reported for zirconia crowns in straight abutments groups and a platform of 4.5, 3.5, and 3 mm diameter was 438.2± 85.4, 345.5± 71.3, and 331.1± 59.1 N, respectively. However, the groups restored with zirconia crowns in angulated abutments groups and a platform of 4.5, 3.5, or 3 mm diameter showed a fracture load of 411.4 ± 49.8, 354.2 ± 52.5, and 302.8 ± 52.5 N, respectively. CONCLUSION: Straight and angulated zirconia abutments presented similar load to fracture on 3 and 3.5 mm platform diameters yet being significantly less for 4.5 mm diameter.
OBJECTIVE: The aim of this study was to assess the impact of implant platform diameters on ultimate force to failure of zirconia abutments with different angulation. MATERIALS AND METHODS: Forty-two zirconia abutments with either 0 degree (ST) or 15-degree (AN) angulation were assembled on tapered internal connection titanium implants (Direct's Legacy; 13 mm Implant Direct, LLC, Las Vegas, United States) with a platform diameter of Ø3.0, Ø3.5, and Ø4.5 mm (14 per group). Zirconia crowns (Ceramill Zolid; Amann Girrbach GmbH) were fabricated and cemented using self-adhesive resin cement (MaxCem Elite, Kerr). The specimens were thermomechanically loaded (TCML= 6,000 cycles of 5 to 50°C for 2 minutes/cycle followed by cyclic loading 600,000 cycles) followed by static loading until fracture. The data of load (N) at which fracture occurred were statistically analyzed by using Kruskal-Wallis analysis of variance and Mann-Whitney U tests at 5% significance level. RESULTS: Higher load to fracture was reported for zirconia crowns in straight abutments groups and a platform of 4.5, 3.5, and 3 mm diameter was 438.2± 85.4, 345.5± 71.3, and 331.1± 59.1 N, respectively. However, the groups restored with zirconia crowns in angulated abutments groups and a platform of 4.5, 3.5, or 3 mm diameter showed a fracture load of 411.4 ± 49.8, 354.2 ± 52.5, and 302.8 ± 52.5 N, respectively. CONCLUSION: Straight and angulated zirconia abutments presented similar load to fracture on 3 and 3.5 mm platform diameters yet being significantly less for 4.5 mm diameter.