Student Theses, Dissertations and Capstones

Document Type

Thesis - NSU Access Only

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

Jeffrey Thompson

Date of original Performance / Presentation

January 2023

Publication Date / Copyright Date

1-1-2023

Abstract

INFLUENCE OF MATERIAL & TECHNIQUE OF CONVERSION ON INTERIM PROSTHESIS FRACTURE DEGREE DATE: AUGUST 2023 JOHN V BENDER, D.M.D. COLLEGE OF DENTAL MEDICINE, NOVA SOUTHEASTERN UNIVERISTY Thesis Directed By: JEFFREY Y. THOMPSON, Ph.D., COMMITTEE CHAIR JACK PIERMATTI, D.M.D., COMMITTEE MEMBER DANIEL FEIT, D.M.D., COMMITTEE MEMBER Introduction: Denture conversions are life-changing dental appointments and have been happening every day for the last 35 years. The “denture conversion” is a dental procedure where a patient’s existing removable denture gets converted into a full arch of teeth that is screwed onto dental implants. In one appointment, the dental patient goes from living with removable teeth to fixed teeth. Literature has recognized a flaw in the denture conversion prosthesis – high incidence of interim prosthesis fracture. Prosthetic fracture is a complication that has led to implant failure, especially dangerous during the osseointegration period. While the grinding of holes in the denture makes for a rapid and predictable conversion process, it also weakens the temporary teeth.1 The author believes that due to smaller preparation holes, the “Smart Denture Conversion” (SDC) technique produces more durable prosthetics. Materials and Methods: Three materials (3D Printed resin, Injection Molded PMMA, Milled PMMA) were used to fabricate 180 specimens, 60 specimens per material. Then, all 180 specimens were divided in half and assigned a conversion technique: either the traditional denture conversion or the Smart Denture Conversion. All denture conversions were performed on a pick-up jig with two multiunit abutment replicas encased in the pick-up jig. 30 Ivoclar PMMA injection molding specimens underwent a conventional denture conversion and 30 Ivoclar PMMA injection molding specimens underwent a “Smart Denture Conversion” (SDC) protocol. 30 AvaDent Milled PMMA specimens underwent conventional conversion and 30 AvaDent milled PMMA specimens underwent “Smart Denture Conversion” (SDC) protocol. 30 SprintRay OnX Tough resin 3D printed specimens underwent conventional conversion, and 30 SprintRay OnX Tough resin 3D printed specimens underwent “Smart Denture Conversion” (SDC) protocol. A long temporary cylinder is picked up in the conventional conversion technique, while a short TiBase is picked up in the (SDC) technique. All 180 specimens were filled with general purpose acrylic resin powder & monomer during the pick-up step of the denture conversion. All excess was removed while maintaining the uniform dimensions of specimens. All specimens were then gradually finished with 600-grit sandpaper. Each specimen was fractured using a 3-point bend test on an Instron machine with a static load test (Instron, Canton, MA, USA). A two-way ANOVA with Material (3D Printed Resin, Injection PMMA, Milled PMMA), Method of Conversion (Conventional, Smart Denture Conversion), and the interaction of Material by Method of Conversion was conducted with a Tukey HSD post-hoc comparisons. STATA 18.0 was used in the analysis and a p value less than 0.05 are considered statistically significant. Results: Results from this study are described as: method of conversion, material, and method of conversion*material. Method of conversion was statistically significant for mean fracture strength resulting in a P value < 0.037. Choice of material showed statistically significant results for mean fracture strength with a P value < 0.000. Combination of Method of Conversion * Material showed a statistically significant result for mean fracture strength with a P value < 0.000. Summary statistics are presented in Table 1. The ANOVA table with omega-squared (effect size) are presented in Table 2. False discovery comparisons are presented in Table 3. A significant difference was found by method of conversion, material, and the interaction of method of conversion by material. The combination of OnX Tough 3D printed specimens converted with Smart Denture Conversion yielded the highest mean fracture strength, and also the highest individual fracture strength value. Reviewing the Omega squared indicates that the interaction of Method of Conversion by Material accounts for 8.8% of the variation, Material 8.7%, and Method of Conversion 2%. Conclusion: In conclusion, the specimens made from OnX Tough 3D printed material converted using the “Smart Denture Conversion” technique had the highest mean fracture strength and highest individual fracture strength value at 79.2 MPa (mean) and 120.7 MPA (individual). The lowest mean fracture strength and lowest individual fracture strength recorded were specimens made from Injection Molding PMMA converted using the conventional conversion technique at 54.4 MPa and 19.9 MPA. The mutilation of denture base when preparing “through and through” access holes during the conventional conversion technique is a contributing factor towards decreased mean fracture strength and individual fracture strength values. Based on this study, the author advises dental clinicians to adopt the “Smart Denture Conversion” technique in combination with 3D printed resin material for fabrication the strongest interim denture conversion prosthesis. Using Smart Denture Conversion technique is also much simpler and faster than the conventional denture conversion technique. This study was supported by NSU HPD Research Grant #334560 and Smart Denture Conversions.

Disciplines

Dentistry

Keywords

Conversion Prosthesis; Dental Implants; Dentist; Implant Denture; Prosthesis Fracture; Smart Denture Conversion

Download

Download Full Text (4.0 MB)

Download
To access this thesis/dissertation you must have a valid nova.edu OR mynsu.nova.edu email address and create an account for NSUWorks.

Free My Thesis

If you are the author of this work and would like to grant permission to make it openly accessible to all, please click the Free My Thesis button.

  Contact Author

Share

 
COinS