Zirconium Oxide Three-Unit Fixed Partial Denture Frameworks Supported by Dental Implants in Acceptable and Reduced Interocclusal Space Possibilities: Pilot In Vitro Fracture Strength and Fractographic Analyses

Abstract

This study investigated the effect of fracture strength and fracture mode characteristics related to reduced interocclusal space on computer-aided design/computer-aided manufacturing (CAD/CAM). ZrO 2 fixed partial denture (FPD) frameworks subjected to quasi-static loads. Materials and Methods: First, two dental implants (4 × 10 mm) were positioned simulating a three-unit FPD (second premolar and second molar abutments). The implants were distributed into two groups: control group (n = 10), positioned at the same level; and the test group (n = 10), where the interocclusal space corresponding to the second molar was reduced by 3 mm in relation to the second premolar to simulate a clinical situation. After FPD wax-up (25-mm long; connector height = 5 mm; connector width = 3 mm, proximal and lingual collar reinforcement), casting was made in a Co-Cr alloy to serve as a prototype. Upon scanning, screw-retained CAD/CAM ZrO 2 FPDs were fabricated for each group. Then, FPDs were subjected to quasi-static axial loading until fracture in the mid-occlusal pontic area using a universal testing machine at the crosshead speed of 0.5 mm/min. Next, the samples were analyzed by scanning electronic microscopy (SEM) to describe the fracture characteristics. Results: The mean fracture strength values for the control group (1,747.4 ± 122.3 N) and test group (1,817.7 ± 158.9 N) showed no significant difference (Student t test, P < .124). The SEM images of the fracture sites revealed two cleavage areas in the test group, providing representative sites with increased fracture energy storage in this group compared with the control group. Conclusion: Within the limitations of this study, the results showed that reduced interocclusal space and reduced length did not decrease the fracture strength of the ZrO 2 FPD frameworks.

Evaluation of Fracture Resistance of Long Span Implant Supported Fixed Dental Prostheses Fabricated from Different CAD/CAM Materials.

“…(20) Several studies measured the fracture load of zirconia restorations, the results were between (897-2489 N). (5,(21)(22)(23)(24)(25)(26)(27)(28)(29)(30)(31)(32)(33) Multiple studies evaluated the fracture load of PEEK restorations, the results were between (802-3132 N). (5,28,(32)(33)(34)(35)(36)(37) Several studies evaluated the fracture load of PEKK restorations, the results were between (310-2037N).…”

Stress distribution around dental implants, generated by six different ceramic materials for unitary restoration: An experimental photoelastic study

“…2,3 Zirconia is already widely accepted as a restorative material due to its biocompatibility and resistance properties, although it has poorer esthetic qualities as compared to the previously mentioned materials. 4,5 Actually, there is controversy about the use of zirconia without ceramic coating due to its great hardness. There is a possibility of excessive wear of the opposing part and of the transmission of loads to the supporting structures in the case of materials with such hardness.…”