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Biomedical subjects

H H Thayer

Publications and source records attributed to H H Thayer.

9 recordsLinked to original sources
PubMed1980

Photoelastic stess analysis of overdenture attachments.

This is a summary of various investigations designed to study the transmission of forces through overdenture abutments to the remaining oral structures: 1. The best design for uniform distribution of occlusal forces to the remaining structures was the conventional design, particularly the amalgam restored abutment. This design, however, provided less effective retention and stability than the other designs. 2. In the group of stud type attachments studied, the Ancrofix transferred stress in a more favorable manner to the remaining structures in the oral cavity when compared to the other stud attachments. 3. The Hader Bar provided more desirable effects to the abutments and remaining structures than did the other tissue bars. 4. The major objective in the choice of an overdenture attachment should be the consideration of how the stress is transferred from these attachments through the abutments and other structures, not the retnetion and stability.

Dental Abutments↗
PubMed1980

Overdentures and the periodontium.

Many reasons have been clarified for the retention of teeth in the oral cavity for use as overdenture abutments. The benefits afforded the patient by the preservation of the periodontium have been explained, and methods have been discussed to evaluate the zone of attached gingiva around overdenture abutments. Finally, some research has been discussed to compare some representative overdenture attachments and provide some guidelines for their use in order to more carefully preserve the periodontium.

Alveolar Process↗
PubMed1979

Occlusal force transmission by overdenture attachments.

This investigation utilized a composite photoelastic model to examine the load-transfer characteristics of several overdenture attachments. Tissue bar (Hader and King Connector) and stud (extracoronal) attachments (Rotherman, Gerber, and Ancrofix) were studied. The following observations may provide guidelines for the selection of overdenture attachments. 1. The more retentive tissue bar and extracoronal attachments produced higher stress concentrations. 2. Of the tissue bars tested, the Hader Bar produced less torquing forces on the abutment teeth. 3. The Ancrofix appeared to share the forces of occlusion between abutments and the posterior edentulous regions. 4. It must be emphasized that several other factors will also influence the choice of overdenture attachments, such as the judgment of the dentist, economics with respect to the patient, and the availability of laboratory expertise.

Alveolar Process↗
PubMed1977

Effects of overdentures upon remaining oral structures.

This study provided the following guidelines in the selection of specific designs for overdenture abutments: 1. The Dolder bar, which exhibits more cross-arch involvement than the Zest anchor, will share the occlusal load across the arch, between the abutments and the supporting structures. 2. The posterior edentulous regions will receive some physiologic stimulation with the Dolder bar, for it shares more stress here than the Zest anchor. 3. The forces on the Dolder bar produce stress directed more apically than that from the Zest anchor. Since this force is better tolerated, use of the Dolder bar may be indicated for a short-rooted tooth with less supporting bone. 4. The greater stress concentrated around the abutment teeth by the Zest anchor makes use of this design in a tooth that is periodontally sound and has a long root structure well imbedded in supporting bone seem logical.

Dental Abutments↗