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

Leila Ahmadian

Date of original Performance / Presentation

January 2021

Publication Date / Copyright Date

1-1-2021

Abstract

Brief Background: Provisional restorations for long or short-term applications aim to promote gingival and periodontal health, stabilize teeth condition, and to prevent any cariogenic activities during the interim therapeutic period. With the variety of dental materials and technologies, some materials work better than others due to either the composition of the material, production methods, and the material’s polishability. Aim: The aim of this in-vitro study is to evaluate the bacterial adhesion to conventionally processed, milled, and 3D printed provisional resin materials after surface polishing. Methodology: Five tooth colored resin materials were used to fabricate 100 symmetrical disc-shaped samples (12x12x2 mm) (20/each) as: two 3D printed resins (NextDent® C&B MFH, NextDent, Netherlands and Dentca® Crown & Bridge, Dentca, CA), one CAD/CAM resin (Telio CAD®, Ivoclar Vivadent, Amherst, NY) and two auto-polymerizing resins, Luxatemp® Ultra, DMG, Germany, and Jet® Tooth Shade Acrylic, Wheeling, Illinois). Samples were immersed in distilled water at 37oC, stored in an incubator for 24 hours. The samples of each material were subgrouped to polished, using Sof Lex ™ (3M, ESPE, USA), and non-polished subgroups. Surface gloss (Gu) and surface roughness (Ra) measurements were done on 3 randomly selected samples from each subgroup. Scanning Electron Microscope (SEM) was used to visualize surface roughness with and without polishing. For bacterial adhesion evaluation, samples were coated by 1 ml of artificial saliva for 1 hour, then, 1x 108 CFU/ml bacterial suspension of Streptococcus mutans (S. mutans) was added to samples, incubated at 37°C for 24h. After that, samples were washed and brushed for 30 s. and washing product was diluted and added 100ul to Brain Heart Infusion (BHI) agar plates and incubated for 24 h. S. mutans colonies observed on the agar plate were counted as colony-forming units (CFU) per ml of stimulated suspension. Finally, Data were analyzed with general linear model procedure (ANOVA, followed by Tuckey’s t-test to measure differences. Results: Glossometric results showed a significant difference between polished and non-polished groups (P≤0.05). Milled samples are significantly glosser than others, no significant difference between 3D printed materials and between conventionally processed resins. Surface roughness means of non-polished groups are much higher than polished ones and there are no significant differences in the polished condition with all processing methods. For s. mutans adhesion, changes from non- polished to polished do not differ between groups. However, the main effects show that non-polished is higher than polished in the conventionally processed groups only. When looking only at production methods, there are no significant differences in the polished condition, but the conventional production is significantly higher than the 3D printed and milled production in the non-polished condition. Conclusion. It can be concluded that, polishing in all tests reflected the high importance on surface roughness and surface gloss. Although after polishing there was no significant difference between processing groups, for bacterial adhesion, digitally processed samples presented better but not significant results than conventionally processed materials.

Disciplines

Dentistry

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