The Influence of Implant Number and Location on Load Transfer in Maxillary Overdenture
Date Issued
2015
Date
2015
Author(s)
Chen, Yi-Chen
Abstract
Objectives: Using the conventional complete dentures in clinical application, dentists often face the patient’s complaint about dentures loosening or poor stability. With the help of dental implants, most of these problems can be solved. In recent years, there have been many studies supporting that the use of two-implant overdenture should be the first choice of treatment for the edentulous mandible. However, similar studies about maxillary overdentures are not sufficient to make any recommendation. Therefore, the purpose of this study was to evaluate the influence of implant number and location in maxillary overdenture on load transfer, by miniature strain gauge and load cell methods. Materials and Methods: A maxillary edentulous model with three identical single dentures (n=3) were fabricated by using a polymethyl methacrylate resin. Six implants (3.75x10 mm, MarkIII, Brånemark, Sweden) were embedded at canine, second premolar and first molar regions bilaterally. A miniature strain gauge (KFG-02-120-C1-11, Kyowa, Japan) was attached on the model adjacent to each implant mesially or distally site. A load cell (LMA-A-200 N, Kyowa, Japan) was placed at the hard palate area. The control group without any attachments (Locator, Zest Anchors, Inc, Escondido, Calif., U.S.A) connected was abbreviated as IOD 0. The group with 2 attachments connected at bilateral canine regions was abbreviated as IOD 2; the group with 4 attachments connected at bilateral canine and second premolar regions was abbreviated as IOD 4(3-5); the group with 4 attachments connected at bilateral canine and first molar regions was abbreviated as IOD 4(3-6); the group with 6 attachments connected at bilateral canine, second premolar and first molar regions was abbreviated as IOD 6. A vertical static load of 100N was applied to the overdenture on a biting plate for 10 times on each group. (p<0.05) Results: Regarding to the strain occurring around implants, the largest strain value was found at the most posterior implant when an attachment was connected. Besides, comparing to the control group, the stress value from load cell decreased as the number of implants increased and the distal implant located more distally. Conclusion: Within the limitation of this study, we concluded: 1. Implant numbers and locations will influence the stress distribution. 2. Four implants may provide sufficient support for maxillary overdentures while Locator attachment using. 3. Increasing the distance between the most anterior and posterior implants resulted in additional support which changed the overdenture from tissue-implant-supported to fully implant-supported.
Subjects
stress distribution
strain gauge
load cell
implant overdenture
attachment
Type
thesis
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