Syed Ershad Ahmed, (2016) Comparative Evaluation of the Effect of Cyclic Loading on the Abutment Screw Loosening of Premachined and Custom Cast Angled Implant Abutments: An In Vitro study. Masters thesis, Ragas Dental College and Hospital, Chennai.
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Abstract
Purpose of the study: To comparatively evaluate in vitro, the effect of cyclic loading on the abutment screw loosening of premachined and custom cast angled implant abutments. Materials and methods: Ten 250 angled premachined titanium abutments (Group I) and ten 250 angled custom cast cobalt-chromium abutments (Co-Cr) (Group II) were connected to their respective titanium implants which were then mounted in stainless steel blocks. Cement-cum-screw retained nickel-chromium cast crowns were fabricated. Abutment screws were torqued to 35Ncm to their respective implants. Reverse Torque Values were measured using a digital torque meter before cycling loading and all the twenty samples were subjected to cyclic loading simulating 6 months of function. Reverse torque values were measured after cyclic loading. The results were statistically analyzed using Paired ‘t’ test and Independent ‘t’ test. Results: Mean pre-cyclic loading reverse torque values were 28.96 Ncm (Group I) and 26.01 Ncm (Group II) and mean post-cyclic loading reverse torque values were 25.84 Ncm (Group I) and 23.82 Ncm (Group II) respectively. There was significantly greater loss of preload for Group II test samples prior to cyclic loading compared to Group I test samples. Cyclic loading resulted in a significant reduction (p<0.01) of the reverse torque values for both Group I and Group II test samples indicating screw loosening. Group II test samples showed significantly greater screw loosening than Group I test samples after cyclic loading. Conclusion: Cyclic loading resulted in significant screw loosening within both test groups. Screw loosening was found to be significantly less for 250 angled premachined titanium abutments than 250 custom cast cobalt chromium (Co-Cr) abutments both before and after cyclic loading.
| Item Type: | Thesis (Masters) |
|---|---|
| Uncontrolled Keywords: | angled abutments, cast angled abutments, reverse torque value, cyclic loading, digital torque meter, screw loosening. |
| Subjects: | DENTAL > Prosthodontics and Crown and Bridge |
| Depositing User: | Subramani R |
| Date Deposited: | 22 Sep 2021 10:39 |
| Last Modified: | 22 Sep 2021 10:39 |
| URI: | http://repository-tnmgrmu.ac.in/id/eprint/18075 |
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