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Objective: This study compared the flexural strength, surface hardness, and surface roughness of conventional, milled, and three-dimensional (3D)-printed provisional restorations.
Materials And Methods: Bar-shaped polymethyl methacrylate (PMMA) specimens (25 × 2 × 2 mm) and disc-shaped specimens (9 × 2 mm) were fabricated using three different techniques ( = 10/group): conventional (SR Ivocron C&B, Ivoclar Vivadent, Schaan, Liechtenstein), milling (Aidite Temp PMMA Blocks, Aidite, Qinhuangdao, China), and 3D printing (Asiga DentaTOOTH, Asiga, Sydney, Australia). Flexural strength was evaluated using a universal testing machine until fracture occurred. Vickers hardness and surface roughness tests were performed on the disc-shaped specimens using a micro-Vickers hardness tester and atomic force microscopy, respectively.
Statistical Analysis: Data were statistically analyzed using one-way ANOVA. The post hoc Tukey's honest significant difference was conducted to compare the differences value between groups ( < 0.05).
Results: The milled computer-aided design/computer-aided manufacturing (CAD/CAM) provisional restorative material exhibited a significantly higher flexural strength (125.16 ± 6.83 MPa) compared with both the traditional (109.74 ± 14.14 MPa) and 3D-printed (71.09 ± 9.09 MPa) materials ( < 0.05). The conventional material had a higher Vickers hardness (19.27 ± 0.41 kgf/mm) compared with the milled (18.53 ± 0.32 kgf/mm) and 3D-printed (17.80 ± 1.85 kgf/mm) materials, though the difference was statistically significant only between the conventional and 3D-printed groups. The surface roughness of the milled CAD/CAM material (8.80 ± 2.70 nm) was significantly lower than that of the 3D-printed material (24.27 ± 9.82 nm) ( < 0.05).
Conclusion: The provisional restorations fabricated using milled PMMA technology provide adequate flexural strength, surface hardness, and low surface roughness, offering a viable alternative for creating provisional restorations.
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http://dx.doi.org/10.1055/s-0044-1791965 | DOI Listing |
Environ Res
September 2025
School of Resources and Safety Engineering, University of Science and Technology Beijing, Beijing 100083, China; Key Laboratory of Safe and Green Mining of Metal Mines with Cemented Paste Backfill, National Mine Safety Administration, University of Science and Technology Beijing, Beijing 100083, Chi
Cemented paste backfill has made outstanding contributions to the large-scale consumption of phosphogypsum (PG), but poor water resistance significantly weakens the mechanical strength, promotes the leaching of total soluble phosphate (TP) and fluoride ions (F), and reduces its attractiveness in mine engineering. This research synthesized a curing agent (CA) using sodium methylsilicate, sodium silicate, and polyaluminum chloride (PAC). PG produced from Deyang Haohua Qingping Phosphate Mine Co.
View Article and Find Full Text PDFProc Inst Mech Eng H
September 2025
Faculty of Medicine, Sirindhorn School of Prosthetics and Orthotics, Siriraj Hospital, Mahidol University, Bangkok, 10700 Thailand.
This study provides valuable guidance for simplifying fabrication procedures and enhancing the structural integrity and safety of carbon fiber (CF) laminate transfemoral (TF) prosthetic sockets. While the high specific strength of CF laminate sockets offers advantages over conventional plastics, essential production data-their orientation-dependent strength and optimal cure conditions-are lacking, often requiring complex, costly cure cycles. This study investigated (i) the influence of fiber orientation on TF prosthetic CF socket strength via finite element analysis (FEA) during standing, and (ii) optimal single-step Vacuum-Bag-Only (VBO) cure conditions for prepreg in a low-cost conventional oven.
View Article and Find Full Text PDFUnlabelled: Dual-energy x-ray absorptiometry (DXA)-derived areal bone mineral density (BMD) remains the clinical standard for assessing osteoporosis risk, yet it fails to identify over 75% of individuals who sustain fragility fractures. Direct in vivo mechanical assessment of cortical bone strength may address this diagnostic gap by capturing structural and material properties that govern whole-bone strength but are not reflected by BMD. We conducted a multicenter case-control study with cross-sectional assessment to compare ulna flexural rigidity, a biomechanical property correlated with whole-bone strength (R² ≈ 0.
View Article and Find Full Text PDFInt J Biol Macromol
September 2025
Department of Mechanical Engineering, Punjab Engineering College, Chandigarh 160012, India.
Natural fiber-reinforced biocomposites have gained the attention of researchers in the fields of household, aerospace, and automobile due to their low density, biodegradability, and recyclability. Regardless of these advantages, biocomposites possess certain limitations, such as moisture absorption, weak fiber-matrix adhesion, and poor flammability. To address this issue, fiber surfaces were modified in the present research investigation with a novel electroless copper coating process.
View Article and Find Full Text PDFJ Prosthet Dent
September 2025
Associate Professor, Division of Restorative Sciences, Adams School of Dentistry, University of North Carolina at Chapel Hill, Chapel Hill, NC.
Statement Of Problem: The effect of food-simulating solvents (FSSs) on the staining susceptibility and mechanical properties of partially and fully crystallized lithium disilicate glass-ceramics (LDGCs) remains unclear.
Purpose: The purpose of this in vitro study was to evaluate the color change, hardness, flexural strength, and reliability of LDGCs exposed to FSSs.
Material And Methods: Two machinable LDGCs, partially crystallized (IPS e.