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Flexural Strength and Radiodensity of Different Barium Sulfate-Containing Polymethyl Methacrylate Provisional
Niwut Juntavee1, Apa Juntavee2, Kesinee Rattanatussanee3
1Department of Prosthodontics, Faculty of Dentistry, Khon Kaen University, Khon Kaen, Thailand.
Objectives:
Provisional restoration fabricated from polymethyl methacrylate (PMMA) faces radiographic clarification due to its radiolucency. This study determined the appropriate radiodensity and strength of auto-polymerized PMMA (P) upon adding barium sulfate (B) at different concentrations.
Materials And Methods:
A total of 90 specimens (length × width × height = 30 × 12.5 × 2.0 mm) were prepared from P containing B at different ratios (volume %B): 5P-0B (0%), 4P-1B (20%), 3P-1B (25%), 2P-1B (33.3%), 1P-1B (50%), and 1P-2B (66.7%) (n = 15/group). Specimens were CBCT (cone-beam computed tomography)-scanned and their radiodensity measured in Hounsfield units (HU). A three-point bending test was used to determine flexural strength (σ).
Statistical Analysis:
ANOVA (analysis of variance) and Tukey tests were used for analyzing significant differences in radiodensity and σ among groups (α = 0.05). The correlation coefficient (R) between radiodensity and σ was determined with the Spearman test.
Results:
Radiodensity (HU) was intense in 1P-2B (1,080.28 ± 119.8) and softest in 5P-0B (-283.3 ± 73.8), whereas σ (MPa) was highest in 5P-0B (60.3 ± 15.2) and lowest in 1P-2B (15.9 ± 3.4). Significant differences in radiodensity among groups (p < 0.05) were indicated, except between 4P-1B/3P-1B/2P-1B and 2P-1B/1P-1B. Significant differences in σ among groups (p < 0.05) were indicated, except between 3P-1B/2P-1B and 1P-1B/1P-2B. Increasing amount of B intensified radiodensity, but diminished σ, with extreme negative correlation (R = -0.83).
Conclusion:
Radiodensity and σ were influenced by the amount of B addition. Raising B intensifies radiopacity but lessens σ. Adding B up to 25% provides adequate radiopacity and strength for provisional restorations for use in high-stress areas. However, adding B ≥33.3% provides better radiographic visibility but minimized strength, suggesting restorations in less-stress areas or other appliances, such as radiographic and surgical guides.
