Marginal Accuracy and Fracture Strength of Implant Supported Zirconia Copings Constructed Using CAD/CAM and MAD/MAM Techniques

Abstract

Purpose. The purpose of this study was to evaluate the marginal accuracy and fracture strength of single implant supported zirconia copings constructed using two different techniques; CAD/CAM and MAD/ MAM process. Materials and Methods: twenty titanium dummy implants with their respective zirconia abutments representing mandibularfirst premolar were embedded in epoxy resin blocks. Samples were divided into two groups according to the milling technique used for constructing zirconia copings: Group (I), (n=10): Zirconia copings milled using CAD/CAM system. Group (II), (n=10): Zirconia copings milled using MAD/MAM system. All samples were subjected to a fatigue procedurecomposed of 20,000 cycles of cyclic loading at 89 N. Marginal accuracy was determined using digital stereomicroscope. All specimens were loaded in a universal testing machine with the compressive load (N) applied within the long axis of the specimen to determine the fracture resisitance. Failure load was recorded for each specimen. Data were statistically analyzed. Results: CAD/CAM copings, group (I), recorded higher mean vertical marginal gap distance value (27.05 ±5.57μm) than MAD/MAM copings, group (II), which recorded lower vertical marginal gap distance (20.72 ± 4.35μm). MAD/MAM samples, group (II), recorded higher mean failure load value (703.35 ± 44.07 N) in comparison to CAD/CAM samples, group (I), (416.06 ± 25.59 N). Conclusions: MAD/MAM samples showed superior marginal accuracyand fracture strength than CAD/CAM samples.