Effect of grinding conditions on flexural strength and surface finish of dental ceramics
Date
2016
DOI
Authors
Alayad, Abdullah Saeed
Version
OA Version
Citation
Abstract
Objectives: Intraoral adjustments and grinding are necessary procedures to achieve accurate fit and proper function of CAD /CA M milled prostheses. However, they are also an important factor that may incur surface damage and clinical failure of dental prosthesis. Objectives of this study were to evaluate and compare the effects of different diamond grit size, different coolant fluids, two depth of cuts and two number of cuts on flexural strength, surface roughness in longitudinal and transverse directions and microstructural changes of four CAD /CAM dental ceramics.
Materials and methods: Four CAD/CAM dental ceramics were used in this study, Vita In-Ceram YZ, IPS e.max CAD, VITABLOCS Mark II and Vita ENA MIC. The blocks of each material were sectioned into bending bars 15 x 5 x 2 mm dimensions. Required sintering or crystallization was applied and recommended polishing procedures were conducted using specific sequence. The initial flexural strength and surface roughness in longitudinal and transverse directions measured on 3 specimens for each material. The remaining bending bars were allocated into testing groups according to design of experiment (DOE) based on the factors of standardized grinding with different grit size (fine 27-76µrn, medium 64- I 26 tm and coarse I 07-181 tm) diamond bur, three coolant fluids (Water, l :5 mouthwash and 4%boric ac id), two depth of cuts (25 µm and 50 tm) and number of cuts (one cut and two cuts). The surface roughness of ground specimens were measured and subsequently loaded to fracture (three point bend test) and analyzed by SEM. Data were statistically analyzed using ANOVA and Post Hoc tests Tukey-Kramer HSD test for multiple comparisons at a=0.05.
Result: The effect of grit size, coolant fluids, depth of cuts and number of cuts on decreasing the flexural strength and increasing surface roughness are different from material to material.
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Dissertation (DScD)--Boston University, Henry M. Goldman School of Dental Medicine, 2016 (Department of Restorative Sciences and Biomaterials)
Includes bibliographic references: leaves 211-225.
Dissertation (DScD)--Boston University, Henry M. Goldman School of Dental Medicine, 2016 (Department of Restorative Sciences and Biomaterials)
Includes bibliographic references: leaves 211-225.
License
This work is protected by copyright. Downloading is restricted to the BU community. If you are the author of this work and would like to make it publicly available, please contact open-help@bu.edu.