Objective: The aim of this study was to observe the resin/dentin interfaces of universal adhesives by using scanning electron microscopy (SEM), and to compare their morphologies with conventional etch & rinse (ER) and self-etch (SE) adhesive systems.
Methods: Two three-step and one two-step ER adhesives and two two-step and two single-step SE adhesives were used for comparison with seven universal adhesives in ER mode and SE mode, respectively. Bonded surfaces with bovine teeth were longitudinally sectioned and mirror-polished. Half of the samples were treated with HCl and NaOCl solutions. The interfaces were subjected to argon ion beam etching and then observed by scanning electron microscopy.
Results: The thickness of the adhesive layer (AL) of most of the seven universal adhesives and single-step SE adhesives was similar. Universal adhesives in SE mode formed a hybrid smear layer as a high-density zone between the AL and dentin. The thickness of the hybrid layer (HL) of the universal adhesives in ER mode was ∼1-2μm, with a high-density zone (reaction layer [RL]) below the HL.
Conclusion: The morphological features of most universal adhesives in SE mode and single-step SE adhesives are similar. Although resin-dentin interfaces of universal adhesives in ER mode resemble those of ER adhesives, universal adhesives have a distinctive feature, an RL.
Significance: The RL might be a sign of chemical bonding even when using universal adhesives in ER mode.
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http://dx.doi.org/10.1016/j.dental.2019.10.006 | DOI Listing |
Research (Wash D C)
October 2023
State Key Laboratory of Analytical Chemistry for Life Science, State Key Laboratory of Pollution Control and Resource Reuse, School of Chemistry and Chemical Engineering, School of the Environment, Nanjing University, Nanjing 210023, P. R. China.
Electrochemiluminescence (ECL) has established itself as an excellent transduction technique in biosensing and light-emitting device, while conventional ECL mechanism depending on spontaneous emission of luminophores lacks reversibility and tunable emission characters, limiting the universality of ECL technique in the fields of fundamental research and clinical applications. Here, we report the first observation of stimulated emission route in ECL and thus establish a reversible tuning ECL microscopy for single-cell imaging. This microscopy uses a focused red-shifted beam to transfer spontaneous ECL into stimulated ECL, which enables selective and reversible tuning of ECL emission from homogeneous solution, single particles, and single cells.
View Article and Find Full Text PDFMed Sci Monit
January 2025
College of Dentistry, King Khalid University, Abha, Saudi Arabia.
BACKGROUND Indirect ceramic restorations often need multiple firings to match the shade of natural teeth or need after-correction and ceramic addition during the clinical trial stage. Many studies have examined how multiple firings affect the mechanical characteristics of zirconia-veneered prostheses. The effect of firing number on adhesion between these core and heat-pressed lithium disilicate veneering ceramics is unclear.
View Article and Find Full Text PDFSci Rep
January 2025
Conservative Dentistry Department, Faculty of Dentistry, Mansoura University, Mansoura, Egypt.
This study aimed to compare the bonding efficacy three bioactive self-adhesive restorative systems to dentin. A total of 80 permanent human molars were utilized in this study. The occlusal enamel was removed to exposed mid-coronal dentin; 40 molars were used for microshear bond strength testing, while the remaining molars were used for micromorphological analysis of restoration/dentin interface.
View Article and Find Full Text PDFLasers Med Sci
January 2025
Department of Preventive and Restorative Dentistry, Discipline of Endodontics, Araçatuba School of Dentistry, São Paulo State University - UNESP, Araçatuba, SP, Brazil.
Investigate the impact of antimicrobial photodynamic therapy (aPDT) using different photosensitizers (PSs) such as indocyanine green (IG), curcumin (CC), and methylene blue (MB), with or without intracanal application of calcium hydroxide (CH), on the push-out bond strength of glass-fiber posts (GFPs) to intraradicular dentin, the chemical composition of the root substrate, and the sealing of the adhesive interface across different thirds of intraradicular dentin. A total of 112 bovine teeth underwent biomechanical preparation and were divided into eight experimental groups (n = 14 each): Negative control with deionized water; positive control with deionized water + CH; IG group with indocyanine green and infrared laser; IG + CH group; CC group with curcumin and blue LED; CC + CH group; MB group with methylene blue and red laser; and MB + CH group. The push-out bond strength was measured using a universal testing machine (n = 8), and scanning electron microscopy characterized the fracture patterns.
View Article and Find Full Text PDFJ Contemp Dent Pract
October 2024
Department of Dental Biomaterials, Faculty of Dental Medicine for Girls, Al-Azhar University, Cairo, Egypt, Orcid: https://orcid.org/0000-0002-3420-4146.
Aim: To assess the effect of mushrooms, ozone gas, and their combination as cavity disinfectants on the bonding strength of composite to dentin.
Materials And Methods: The study was conducted on 40 sound premolar teeth randomly divided into four groups. Group I: control group, Group II: mushroom group, Group III: Ozone group, and Group IV: mushroom + ozone gas (combination) group.
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