Finite Element Stress Analysis of Overdenture Abutment as a Function of Crown-to-root Ratio

Abstract

In partially edentulous patients with considerable loss of tooth structure, it is recommended that a remaining tooth with a C/R ratio greater than approximately 1.5 should be used as an overdenture abutment to minimize lateral occlusal forces. Abstract Purpose:The clinical decision to use abutments for overdentures in cases with loss of tooth structure has not been fully assessed in relation to the periodontal condition. The aim of this study was to investigate the stresses around overdenture abutments with and without crown restoration for various bone heights.Methods: Three-dimensional finite element models of the mandibular right first and second premolars, a periodontal ligament, and one of five alveolar bone models of different heights were constructed. The crown-to-root ratios at the second premolar were 0.86 (Model A), 1.05 (Model B), 1.28 (Model C), 1.56 (Model D), and 1.96 (Model E). The second premolar root was also modeled without crown restoration. A single oblique load of 80 N at a 30-degree angle distal from the vertical axis was directed at the center of the occlusal or root surface of the second premolar. Results:The maximum stresses were observed at the distal cervical regions for all models. These increased as the crown-to-root ratio increased. The highest maximum stress in the cortical bone (35.8 MPa) was observed in Model E with crown restoration. In the regions near the overdenture abutments, the maximum stresses in the bone and the periodontal ligament were 33.9% to 61.7% lower than those observed near the crown restorations. Conclusion:The use of the premolar as an overdenture abutment in cases with loss of tooth structure can effectively sustain the stress in the periodontal tissues, particularly under conditions of reduced bone height.

Finite Element Study of Stress Distribution with Tooth-Supported Mandibular Overdenture Retained by Ball Attachments or Resilient Telescopic Crowns

“…The maximum von Mises stress of the cortical bone around the canine was concentrated at the cervical region. This result is similar to that found by Tanaka et al and Pan et al 37 38…”

“…The maximum von Mises stress of the cortical bone around the canine was concentrated at the cervical region. This result is similar to that found by Tanaka et al and Pan et al 37,38 Bone overload leads to resorption, whereas no load over the bone induces atrophy and loss of bone. 39 The level of stress associated with bone resorption has not been clearly established in the literature.…”

Comparison of using different bridge prosthetic designs for partial defect restoration through mathematical modeling

“…Total load was 400 N. Such occlusal load was chosen based on the results of previous analogical studies published in peer-reviewed journals. [ 16 17 ] Analysis of stresses and strains at the different components of the model was carried out by colorful representation of stress distribution and the numerical data to provide objective comparison; the stress–strain state of dentition in the normal condition without any defect was determined. All the original data, such as the geometric structure of the model, properties of tissues, size, direction, and load location, were preserved for further comparison with all three mentioned above scenarios of possible prosthetic rehabilitation.…”