Effect of Crown Height on the Screw Stability of Titanium Screw-Retained Crowns.

Yilmaz, Burak; Batak, Burcu; Seghi, Robert; Johnston, William M; Lang, Lisa A (2021). Effect of Crown Height on the Screw Stability of Titanium Screw-Retained Crowns. Journal of prosthodontics, 30(6), pp. 515-519. Wiley 10.1111/jopr.13352

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PURPOSE

The aim of this in vitro study was to evaluate the effect of crown height on the screw stability of screw-retained titanium implant crowns subjected to cyclic loading conditions.

MATERIALS AND METHODS

Twenty-one implants with internal hex connections were placed in epoxy resin holders. Mandibular first molar screw-retained titanium implant crowns with UCLA type, crown-abutment connections were CAD/CAM fabricated. Seven crowns of 3 different heights (6 mm, 10 mm, and 14 mm) were made. The crowns were seated onto the implants and screws were tightened to 30 Ncm. The implants were clamped into holders and stepwise cyclic loads were applied to the occlusal surface at 30-degree angles to the long axes of the crowns. The detorque values were measured after each 5 million cycles. Before increasing the applied load, the crowns were secured with new screws and tightened to 30 Ncm. Failure times, survival estimates and detorque values were then analyzed. (alpha = 0.05).

RESULTS

Crown height did not significantly affect detorque values. However, five 14-mm crowns failed with varying fractures during the 475 N loading condition. Overall, a significantly lower survival for 14 mm crowns was found compared to 6 mm and 10 mm crowns (p = 0.004).

CONCLUSIONS

Crown heights of one-piece screw-retained titanium implant crowns did not significantly affect detorque values. Screw fracture, however, was greater for crown height of 14 mm than those of 6 mm and 10 mm.

Item Type:

Journal Article (Original Article)

Division/Institute:

04 Faculty of Medicine > School of Dental Medicine > Department of Reconstructive Dentistry and Gerodontology
04 Faculty of Medicine > School of Dental Medicine > Department of Preventive, Restorative and Pediatric Dentistry
04 Faculty of Medicine > School of Dental Medicine > Restorative Dentistry, Research

UniBE Contributor:

Yilmaz, Burak

Subjects:

600 Technology > 610 Medicine & health

ISSN:

1532-849X

Publisher:

Wiley

Language:

English

Submitter:

Tina Lauper

Date Deposited:

28 Jun 2021 11:51

Last Modified:

03 Jul 2021 01:34

Publisher DOI:

10.1111/jopr.13352

PubMed ID:

33666307

Uncontrolled Keywords:

Height implant crown screw

BORIS DOI:

10.48350/156974

URI:

https://boris.unibe.ch/id/eprint/156974

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