Student Theses, Dissertations and Capstones

Document Type

Thesis

Degree Name

Master of Science (M.S.) in Dentistry

Copyright Statement

All rights reserved. This publication is intended for use solely by faculty, students, and staff of Nova Southeastern University. No part of this publication may be reproduced, distributed, or transmitted in any form or by any means, now known or later developed, including but not limited to photocopying, recording, or other electronic or mechanical methods, without the prior written permission of the author or the publisher.

Department

College of Dental Medicine

First Advisor

Ana Karina Mascarenhas

Publication Date / Copyright Date

2018

Publisher

Nova Southeastern University

Abstract

Brief Background: The utilization of CAD/CAM technology for dental restorations has various benefits over conventional techniques. These benefits incorporate speed, convenience, quality, and eliminate needing a temporary crown. However, failure of dental restorations is a major issue in dental practice, it needs to be quantified and considered against the benefits here stated. Objectives: To evaluate the clinical performance of ceramic conventional and chairside CAD/CAM Onlay/ crowns placed on posterior teeth by postgraduate student in Operative department. Methods: This retrospective study employed patient record data stored in AxiUm. In total, 78 CAD/CAM all ceramic crowns/ onlays and 429 all ceramic conventional crowns/ onlays were placed on posterior teeth in 225 patients at the Postgraduate Operative clinic at Nova Southeastern University from 2012 to 2018. These restorations were evaluated using the information on the patients AxiUm records. Specifically, information from the medical records of patients attending the clinic from 2012-2018 were employed to determine the survival time of the crown(s) or onlay(s) by fabrication method. A query was conducted in AxiUm to identify all patients who received the restorations of interest from 2012-2018 and examined, across time, to determine if a restoration(s) was replaced or scheduled for replacement. Restorations replaced or scheduled for replacement were coded as failed restorations. A cox proportional-hazards model regression analysis was employed to determine the association between the survival time of crowns by fabrication method and selected predictor variables. Results: Results from the analysis of the data indicated that 429 (84.6%) restorations were fabricated conventionally, and 78 (15.4%) restorations were fabricated via CAD/CAM system. The majority of the patients were female (n=149, 66.2%), while 33.8% were male. Close to half of the patients were designated at or above high caries risk level (47%) and 53.8% of the patients were not using high fluoride toothpaste and/or mouthwash. Molar teeth were most frequently restored (59.5%) while (40%) were premolar teeth. Furthermore, 48% of the patients presented with multiple restorations. There were 19 failed restorations which is equivalent to an overall failure rate of approximately 4% for the restorations placed from 2012 to 2018. Of the 19 failed restorations only two were CAD/CAM fabrications. Overall, the amount of failed restorations was proportionally higher in males, specifically, 88.2% (n=15). The majority of the failed restorations were distributed between the high (n=6) and low (n=10) caries risk groups. There were no significant differences in the survival of crowns across fabrication method and overall survival rate from 2012-2018 was 96%. Results from the Cox regression analysis indicated that gender and high fluoride were associated with survival. In our study, gender was associated with survival time, particularly; the risk of crown failure for females was 5 times higher than for males. Additionally, the risk for crown failure for cases using high fluoride oral treatments was lower than for the group who did not use high fluoride treatment. Although not significant, cases with multiple crown restorations were 5 times more likely to fail. Conclusion: Our findings suggest there are no significant differences between the survival rate of CAD/CAM restorations and conventional restorations. Care needs to be taken in case selection when recommending these crown restorations, particularly multiple crown restorations, gender and use of high fluoride.

Disciplines

Dentistry

Keywords

Fluoride treatment, Survival time of crowns, Risk of crown failure, Crown restorations

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