Master of Science (M.S.) in Dentistry
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College of Dental Medicine
Publication Date / Copyright Date
Nova Southeastern University
Fahad Algahtani. 2018. Evaluation Of Surface Characteristics For Three Milled CAD/CAM Monolithic Ceramic Restorations. Master's thesis. Nova Southeastern University. Retrieved from NSUWorks, College of Dental Medicine. (84)
Background: Dental ceramics have been chosen as the material of choice by patients and clinicians because of their aesthetics, color stability, and low thermal conductivity. Clinically, almost all restorations need some adjustments to allow adequate occlusion and contacts. However, these adjustments will create rough surfaces. Therefore, different surface treatments have been developed to improve surface smoothness and gloss of dental ceramics. Objective: To evaluate the average surface roughness (Ra) and gloss (GU) of three different monolithic ceramics: Lithium Disilicate (IPS e.max CAD), Leucite reinforced (IPS Empress CAD) and Feldspathic (Vitablocs Mark II) subjected to two different surface treatments (mechanical polishing vs reglazing firing procedure). Material and methods: Ten disc-shaped samples (10-mm diameter and 2-mm thick) of each ceramic were prepared, for a total of 60 samples. Ceramics were CAD designed by E4D Technologies and milled to size specification. Then, specimens were glazed following manufacturer’s recommendation and fired in a furnace. A fully adjustable device was used to hold the hand piece to have a standardized pressure. After adjustment, specimens were randomly assigned to one of the surface treatment options: mechanical finishing and polishing by Dialite LD System; or reglazing firing procedure using Enamelite Low-Fusing Ceramic Spray Glaze. A surface profiler was used to assess the surface roughness and gloss values were measured using a gloss meter. Results: Post-hoc tests were conducted using a Bonferroni adjustment. R Studio and R 3.2.2 was used for all statistical analysis, and significance was accepted at p < 0.05. Post-hoc Tukey results indicate mechanical polishing had a significantly lower Ra average than reglazing firing procedure (difference = 1.51, 95% CI:1.27,1.75]. Post-hoc Tukey results indicate reglazing firing procedure had a significantly higher GU average than mechanical polishing (difference = 15.01, 95% CI:14.04,15.96]. Conclusion: All tested CAD/CAM monolithic ceramics presented smoother surfaces and higher gloss at baseline than after subjected to adjustment and surface treatments.
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