Volume 6, Issue 4 (9-2021)
J Res Dent Maxillofac Sci 2021, 6(4): 1-7 |
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Naseri N, Babasafari A, Jalalian E, Mazaheri A, Zarbakhsh A. Effects of cyclic loading on screw loosening, vertical misfit, and microleakage at the fixture-angulated abutment interface. J Res Dent Maxillofac Sci 2021; 6 (4) :1-7
URL: http://jrdms.dentaliau.ac.ir/article-1-322-en.html
URL: http://jrdms.dentaliau.ac.ir/article-1-322-en.html
1- Prosthodontics Dept, Prosthodontics Dept, Faculty of Dentistry, Tehran Medical Sciences, Islamic Azad University, Tehran, Iran
2- Prosthodontics Dept, Prosthodontics Dept, Faculty of Dentistry, Tehran Medical Sciences, Islamic Azad University, Tehran, Iran ,arezu.b.ab@gmail.com
2- Prosthodontics Dept, Prosthodontics Dept, Faculty of Dentistry, Tehran Medical Sciences, Islamic Azad University, Tehran, Iran ,
Abstract: (1953 Views)
Background and Aim: This study assessed the effects of cyclic loading on screw loosening, vertical misfit, and microleakage at the fixture-angulated abutment interface.
Materials and Methods: This in vitro study evaluated 12 implants in two groups (n=6). The implants were mounted in self-cure acrylic resin. The abutment screw was torqued to 30 N/cm by a digital torque-meter and re-torqued after 5 min. Six points at the fixture-abutment interface were inspected under a stereomicroscope (x75 magnification), and the distance between the two reference points was measured. Six implant-abutment assemblies then underwent cyclic loading (75 N, 1 Hz, 500,000 cycles) while the remaining six (control group) were stored at room temperature. The distance was measured again at the same 6 points after cyclic loading. Vertical misfit was calculated by subtracting the before and after values. The torque loss was measured by a digital torque-meter. The assemblies were then immersed in fuchsine and incubated at 37°C for 24 h. Next, the abutment was unscrewed and the fixtures were cut in half. The penetration depth of fuchsine was measured at 3 points of each fixture half under a stereomicroscope at x75 magnification, and the mean of the six measurements (entire fixture) was reported as the microleakage score of each sample. Data were analyzed using t-test.
Results: Cyclic loading significantly increased the misfit (P=0.001) and microleakage (P=0.01), and decreased the detorque value (P=0.04). No case of screw loosening was noted in any group.
Conclusion: Cyclic loading significantly increases the vertical misfit, microleakage, and torque loss.
Materials and Methods: This in vitro study evaluated 12 implants in two groups (n=6). The implants were mounted in self-cure acrylic resin. The abutment screw was torqued to 30 N/cm by a digital torque-meter and re-torqued after 5 min. Six points at the fixture-abutment interface were inspected under a stereomicroscope (x75 magnification), and the distance between the two reference points was measured. Six implant-abutment assemblies then underwent cyclic loading (75 N, 1 Hz, 500,000 cycles) while the remaining six (control group) were stored at room temperature. The distance was measured again at the same 6 points after cyclic loading. Vertical misfit was calculated by subtracting the before and after values. The torque loss was measured by a digital torque-meter. The assemblies were then immersed in fuchsine and incubated at 37°C for 24 h. Next, the abutment was unscrewed and the fixtures were cut in half. The penetration depth of fuchsine was measured at 3 points of each fixture half under a stereomicroscope at x75 magnification, and the mean of the six measurements (entire fixture) was reported as the microleakage score of each sample. Data were analyzed using t-test.
Results: Cyclic loading significantly increased the misfit (P=0.001) and microleakage (P=0.01), and decreased the detorque value (P=0.04). No case of screw loosening was noted in any group.
Conclusion: Cyclic loading significantly increases the vertical misfit, microleakage, and torque loss.
Type of Study: Original article |
Subject:
Dental implant
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