International Journal of Prosthodontics and Restorative Dentistry

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VOLUME 3 , ISSUE 2 ( April-June, 2013 ) > List of Articles

RESEARCH ARTICLE

Comparison between Acetal Resin and Cobalt-Chromium Removable Partial Denture Clasp Retention: An in vitro Study

Tarek Mohamed, Osama Abdulmoneam Baraka, Magdy Mostafa Badawy

Citation Information : Mohamed T, Baraka OA, Badawy MM. Comparison between Acetal Resin and Cobalt-Chromium Removable Partial Denture Clasp Retention: An in vitro Study. Int J Prosthodont Restor Dent 2013; 3 (2):50-56.

DOI: 10.5005/jp-journals-10019-1076

Published Online: 01-06-2013

Copyright Statement:  Copyright © 2013; The Author(s).


Abstract

Statement of problem

The retention qualities of acetal resin clasps are questionable.

Purpose

To asses the initial retention and after cycling for 1,200 cycles of acetal resin clasps as compared to cobalt-chromium clasps.

Materials and methods

Extracted maxillary first premolars and molars were collected. Each tooth was embedded in acrylic block up to the cementoenamel junction. On each block, partial denture model consisted of Akers clasp, minor connector, cobalt-chromium horizontal plate representing the denture base, and a vertical arm on the horizontal plate was constructed. Models were divided into four groups (five each). Group I had acetal resin clasps on premolars. Group II had cobalt-chromium clasps on premolars. Group III had acetal resin clasps on molars. Group IV had cobalt-chromium clasps on molars. Akers clasps were designed to utilize 0.01 inch undercut. Each model was connected to the universal testing machine through the vertical arm. The model was placed in artificial saliva and a tensile load was applied to measure the initial retention. Then retention was measured after cycling for 200, 400, 600, 800, 1,000 and 1,200 cycles. One-way analysis of variance followed by Duncan's multiple range test was used to test the effect of groups and cycling on tensile load required for clasp dislodgment.

Results

Groups I and III showed no change in retention on cycling up to 1,200 cycles. Group I showed significantly higher retention than group III. Groups II and IV showed significant reduction in retention upon cycling more than 800 cycles. In spite of this reduction in retention, it is still higher than that in groups I and III.

Conclusion

Cobalt-chromium clasps showed higher retention than acetal resin clasps despite the deformation encountered in the former. Acetal resin clasps showed more retention qualities on premolar teeth than that on molar teeth.

Clinical implications

Acetal resin clasps can be used to retain Kennedy's class III partial denture. However, when used on molar teeth, it is recommended to increase the thickness of the retentive clasp arm or to use a deeper undercut.

How to cite this article

Mohamed T, Baraka OA, Badawy MM. Comparison between Acetal Resin and Cobalt-Chromium Removable Partial Denture Clasp Retention: An in vitro Study. Int J Prosthodont Restor Dent 2013;3(2):50-56.


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  1. The physical properties of a polyacetal denture resin. Clin Mater 1994;17:125-129.
  2. In vitro deformation of acetyl resin and metal alloy removable partial denture direct retainers. J Prosthet Dent 2003;90:586-590.
  3. An in vitro comparison of retentive force and deformation of acetal resin and cobalt-chromium clasps. J Prosthet Dent 2005;94:267-274.
  4. Flexural properties and surface finishing of acetal resin denture clasps. J Prosthet Dent 1999;8:188-195.
  5. Hidden clasps versus C clasps and I bars: a comparison of retention. J Prosthet Dent 1996;75:622-625.
  6. Stress- relaxation testing (part IV): Clasp pattern dimensions and their influence on clasp behavior. J Prosthet Dent 1983;50:319-326.
  7. Properties of a custom-made hinge clasp compared with a conventional circumferential clasp. J Prosthet Dent 1996;75:326-331.
  8. Effect of clasp design upon retention of removable partial dentures. J Prosthet Dent 1968;20:43-52.
  9. Retention of two types of clasp designs in a long term in vitro study. Cairo, Egypt: DDS Thesis, Al-Azhar University; 2004.
  10. A study of enamel abrasion as related to partial denture clasps. J Prosthet Dent 1956;6:657-671.
  11. Studies on the retention of cobalt-chromium partial dentures. Br Dent J 1968;125:97-102.
  12. Abrasion of enamel and composite resin by removable partial denture clasps. J Prosthet Dent 1984;52:389-397.
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