Purpose: The aim of this in vitro study was to comparatively evaluate the influence of three different light curing units (QTH Hilux, LED SmartLite, PAC Plasmaster) on shear bond strength of an adhesive system (Clearfil SE Bond ) after bleaching.
Materials And Methods: Sixty molars were used for this study. Carbamide peroxide was applied to the floor and wall of the dentin surfaces in bleached groups for 3 weeks. Each week the paste was renewed for the bleached group. Teeth were sectioned mesiodistally. The roots of the sectioned teeth were mounted in a cylindrical mold using chemically cured acrylic resin. Composite resin was added to the center of flattened dentin surfaces with an internal diameter of 3 mm and height of 3 mm. The bonding procedure was performed in the bleached test groups as follows: G1: immediately/QTH; G2: after 1 week/QTH; G3: after 2 weeks/QTH; G4: immediately/LED; G5: after 1 week/LED; G6: after 2 weeks/LED; G7: immediately/PAC; G8: after 1 week/PAC; G9: after 2 weeks/PAC. The non-bleached groups (control group) were G10: QTH; G11: LED; G12: PAC. Specimens were mounted in a universal testing machine and shear load was applied at a crosshead speed of 1 mm/min until failure. Bond strength values were calculated as MPa and the comparisons were made statistically using one-way ANOVA with light source and bleaching treatment) as the two factors.
Results: The mean values of shear bond strength in MPa were: G1 (12.23), G2 (19.18), G3 (23.08), G4 (13.07), G5 (21.01), G6 (25.27), G7 (12.55), G8 (19.06), G9 (25.41), G10 (24.54), G11 (26.99), G12 (25.97). No statistical difference was found between the control group and groups bonded two weeks later. The bond strength values of the control group and those bonded 2 weeks later were higher than other groups. Statistically significant differences were found between the immediate and 1-week groups (p < 0.01). Immediately bonded groups had the lowest bond strength compared to the others (p < 0.05). No significant differences in bond strength were observed among three lightcuring units (p > 0.05).
Conclusion: It was concluded that different light-curing units had no effect on shear bond strength of bleached dentin. A 2-week delay in restoration after bleaching improved the reduced bond strength of resin composite.
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J Comput Chem
January 2025
Department of Chemistry, Dr. Harisingh Gour Vishwavidyalaya, (A Central University), Sagar, India.
We report a direct application of the molecular tailoring approach-based (MTA-based) method to calculate the individual hydrogen bond (HB) energy in molecular crystal. For this purpose, molecular crystals of nitromalonamide (NMA) and salicylic acid (SA) were taken as test cases. Notably, doing a correlated computation using a large molecular crystal structure is difficult.
View Article and Find Full Text PDFEnviron Sci Pollut Res Int
January 2025
Faculty of Civil Engineering, Universiti Teknologi Malaysia, 81310, Skudai, Johor, Malaysia.
Sustainable pavement is essential for country development, offering durable, environmentally friendly, and cost-effective infrastructure. For Malaysia, sustainable pavement supports Sustainable Development Goals (SDGs) 9 and 11 while addressing road deterioration caused by increasing traffic volumes and loads. This deterioration shortens pavement service life and necessitates frequent maintenance, driving the need for innovative solutions.
View Article and Find Full Text PDFSci Rep
January 2025
College of Mechanical and Electrical Engineering, Shihezi University, Shihezi, 832003, China.
In response to the rotary ploughing equipment in the stubble land to implement protective operations, the stubble is large in number and strong in toughness, not easy to crush, resulting in rotary ploughing equipment to produce entanglement and increased resistance to rotary ploughing and other issues. In this study, researchers designed a bionic rotary tillage blade (B-RTB) based on the bionic structural equations of the Marmota claw. A straw-soil complex shear performance test was conducted to investigate the effect of straw on soil shear strength.
View Article and Find Full Text PDFJ Prosthet Dent
January 2025
Assistant Professor, Department of Prosthodontic, College of Dental Medicine, Rangsit University, Phatum Thani, Thailand. Electronic address:
Statement Of Problem: Comprehensive data are needed on the performance of chemically activated, chairside hard reline materials when used with computer-aided design and computer-aided manufacturing (CAD-CAM) milled polymethyl methacrylate (PMMA) denture bases and conventionally processed bases. This lack of data affects decisions regarding the chairside reline material to be used for improving the fit and retention of relined complete dentures.
Purpose: The purpose of this in vitro study was to evaluate and compare the shear bond strength (SBS) of 3 chemically activated, chairside hard reline materials on CAD-CAM milled and conventional heat-polymerized PMMA denture bases.
J Am Chem Soc
January 2025
Institute of Materials for Electronics and Energy Technology (i-MEET), Department of Materials Science and Engineering, Friedrich-Alexander-Universität Erlangen-Nürnberg (FAU), Martensstraße 7, 91058 Erlangen, Germany.
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