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Updated: May 13, 2026
An Improved Mechanical Testing Method to Assess Bone-implant Anchorage
Published on: February 10, 2014
Comparison of mechanical properties of implant-supported prostheses fabricated with different materials and
Züliye Kurultay1, Rüştü Ersoy Sakarya2
1Researcher, Department of Prosthodontics, Faculty of Dentistry, Atatürk University, Erzurum, Turkey.
Statement Of Problem:
Screw loosening and fracture resistance are prevalent complications of implant-supported prostheses. Different materials and abutments and artificial aging should be investigated to prevent these complications.
Purpose:
The aim of this in vitro study was to compare the mechanical properties of 3-unit implant-supported prostheses fabricated using different materials (metal-ceramic, monolithic zirconia, zirconia-based ceramic) and abutments (standard titanium and Ti-base) after thermomechanical aging.
Material And Methods:
Screw-cement-retained metal-ceramic restorations on titanium and Ti-base abutments (Ti-PFM and Ti-base-PFM groups), screw-cement-retained monolithic zirconia restorations (Ti-MoZr and Ti-base-MoZr groups), and screw-cement-retained zirconia-based ceramic restorations (Ti-PFZr and Ti-base-PFZr groups) were fabricated. After tightening, the abutment screws were loosened using a digital torque device to record the initial reverse torque values (RTV1), and the tightening procedure was repeated. The specimens were subjected to cyclic loading (500 000 cycles, 1.6 Hz, 50 N), reverse torque values (RTV) were subsequently measured and recorded as RTV2. Following the same torque procedure, fracture resistance tests were performed using a universal testing machine. Reverse torque values were analyzed using repeated-measures ANOVA, while fracture resistance was evaluated with two-way ANOVA (Levene's test for homogeneity; Tukey HSD for post hoc comparisons).
Results:
Mean RTV decreased significantly after thermomechanical aging (P<.001). Abutment type significantly affected RTV (P<.001), whereas restoration material had no significant effect (P=.399). Postloading torque loss was significantly greater in the titanium-based groups than in the Ti-base groups (P<.05). Similarly, when torque loss (%) before and after loading was compared, groups with Ti-base abutments exhibited significantly higher values than the Ti-MoZr and Ti-PFZr groups (P<.05). PFM restorations showed significantly higher fracture resistance than MoZr and PFZr (P<.001), with no significant difference between MoZr and PFZr (P=.257).
Conclusions:
Thermomechanical aging resulted in screw loosening in all groups and occurred more frequently in Ti-base abutments. All tested materials demonstrated fracture resistance values exceeding physiological masticatory forces. Metal-ceramic restorations supported by titanium abutments demonstrated more favorable mechanical performance in terms of screw stability and fracture resistance.
