Fatigue resistance of a simulated single LOCATOR overdenture system

Mona Gibreel; Lippo V J Lassila; Timo O Närhi; Leila Perea-Lowery; Pekka K Vallittu

doi:10.1016/j.prosdent.2018.11.013

Fatigue resistance of a simulated single LOCATOR overdenture system

J Prosthet Dent. 2019 Dec;122(6):557-563. doi: 10.1016/j.prosdent.2018.11.013. Epub 2019 Apr 12.

Authors

Mona Gibreel¹, Lippo V J Lassila², Timo O Närhi³, Leila Perea-Lowery⁴, Pekka K Vallittu⁵

Affiliations

¹ Doctoral candidate, Department of Biomaterials Science and Turku Clinical Biomaterials Centre-TCBC, Institute of Dentistry, University of Turku, Turku, Finland. Electronic address: mona.f.gibreel@utu.fi.
² Laboratory Head, Turku Clinical Biomaterials Centre-TCBC, Institute of Dentistry, University of Turku, Turku, Finland.
³ Professor and Head, Department of Prosthetic Dentistry and Stomatognathic Physiology, University of Turku, Turku, Finland; Professor, Department of Oral Diseases, Turku University Hospital, Turku, Finland.
⁴ Assistant Professor, Department of Biomaterials Science, Turku Clinical Biomaterials Centre-TCBC, Institute of Dentistry, University of Turku, Turku, Finland.
⁵ Professor, and Chair of Biomaterials Science Department, University of Turku, Turku, Finland; City of Turku, Welfare Division, Turku, Finland.

PMID: 30982623
DOI: 10.1016/j.prosdent.2018.11.013

Abstract

Statement of problem: The incidence of fracture in a single-implant overdenture base increases in the region adjacent to the fulcrum implant.

Purpose: The purpose of this in vitro study was to evaluate the effect of bidirectional woven electrical glass (E-glass) fiber reinforcements on the fatigue resistance of a simulated single LOCATOR-retained overdenture.

Material and methods: Test specimens with a centrally positioned metal housing for a LOCATOR stud attachment were fabricated from autopolymerizing acrylic resin. Specimens for the control group were fabricated without glass fiber reinforcements. The 4L group specimens had 4 layers of E-glass fiber weaves and were divided according to the fiber location into the following 3 subgroups: 4L-A with 4 fiber layers above the metal housing; 4L-N with 4 fiber layers adjacent to the metal housing; and 4L-A+4L-N with 4 fiber layers above and 4 fiber layers adjacent to the housing. Specimens were stored in distilled water for 1 week at 23 °C before cyclic fatigue testing at 10 000 cycles by using a staircase approach (n=12). The results were analyzed with 1-way ANOVA and the Tukey multiple comparisons post hoc analysis (α=.05). A 2-way ANOVA (α=.05) was conducted to detect the effect of fatigue cyclic loading and the position of the fiber layers and their interaction on the fatigue resistance.

Results: The results of the investigated compressive fatigue limits for the test groups were 190 ±15.9 N for the control group, 265 ±15.9 N for the 4L-A subgroup, 220 ±15.9 N for the 4L-N subgroup, and 275 ±15.9 N for the 4L-A+4L-N subgroup. A nonsignificant difference was found for creep values between the control group and reinforced subgroups (P>.05). The postfatigue flexural strength values in the 4L-A and 4L-A+4L-N subgroups were significantly higher than those in the control group (P<.001) and the 4L-N subgroup (P=.004 and P=.005). However, no significant difference was found in postfatigue flexural strength between the control group and the 4L-N subgroup (P=.828).

Conclusions: Placing 4 layers of bidirectional E-glass fiber weaves above the metal housing can increase the fatigue resistance and the postfatigue flexural strength of single LOCATOR-retained overdentures.

MeSH terms

Acrylic Resins
Dental Stress Analysis
Denture, Overlay*
Glass*
Materials Testing
Stress, Mechanical

Substances

Acrylic Resins