Date of Award
Spring 2022
Document Type
Thesis - Restricted
Degree Name
Master of Science (MS)
Department
Dentistry
First Advisor
Ibrahim, Mohamed
Second Advisor
Hashimoto, Lance
Third Advisor
Gaffney, Joseph
Abstract
INTRODUCTION: Endodontic surgery, including root-end resection and root amputation, has been performed for many years with the goal to retain the tooth despite the reduced amount of root structure. The aim of this study was to evaluate the influence of multiple root-end surgery and/or root amputation on the stress distribution in a maxillary first molar using Finite Element Analysis. METHODS: Five 3D printed, pre-accessed maxillary first molars were endodontically treated. Four received surgical retreatment involving root-end resection of the MB root or MB and DB roots or MB root amputation or MB root amputation with root-end resection of the DB root. One left as a control. The five teeth were digitized using a micro-computed tomographic scanner, and stereolithograpic reconstructions were produced for FEA. All sample teeth were evaluated in load scenarios of 250 N and 800 N. The von Mises stresses were analyzed as gradients in axial sections, maximum and minimum values in coronal, middle, and apical thirds, and on the tooth surface. RESULTS: The greatest von Mises stress was in the tooth that received MB root amputation with DB root-end resection at all axial sections. The stress concentrations in the teeth treated with root amputation occurred at the lingual CEJ, DB root CEJ, and buccal aspect of the palatal root. CONCLUSIONS: Based on this 3-D FEA analysis, MB root amputation of maxillary first molars produced greater stresses and altered stress distribution on the remaining root surfaces compared to root-end surgery which might lead to reduced fracture resistance of these teeth.