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Objective: To quantify component volumes (mineral, organic, total water, firmly and loosely bound water volumes, and permeability) at histological points in bovine enamel and investigate their association with bovine enamel's optical behavior and fracture toughness (FT).
Design: In vitro, cross-sectional, and experimental study. Longitudinal ground sections of ten permanent bovine incisors were analyzed using microradiography, polarizing microscopy, microhardness tester, and confocal laser fluorescence microscopy (CLFM). Continuous data were analyzed using regression and correlation tests.
Results: Bovine enamel exhibited gradients in both composition and FT from the surface inward, with the inner third showing positive birefringence in water immersion and opaque areas under immersion in air (explained by composition gradients), along with intermediate FT. Bovine enamel presented mineral volume of 79.6 % ( ± 2.7 %), water volume of 11.4 % ( ± 20.4 %), organic volume of 9.1 % ( ± 2.4 %), and permeability of 6.5 % ( ± 0.5 %). Water loss upon air drying was 1/5th of that in human enamel, representing a novel finding in enamel biology. The organic gradient was confirmed by CLFM. The ratio of firmly bound water to organic content was negatively associated with fracture toughness across the enamel layer.
Conclusion: bovine enamel differs from human enamel in terms of composition, birefringence, and permeability, requiring caution when interpreting results from studies using it to test dental products intended for humans. The composition of bovine enamel fully explained its optical behavior and partially explained its FT gradient.
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http://dx.doi.org/10.1016/j.archoralbio.2025.106215 | DOI Listing |
J Appl Oral Sci
September 2025
Universidade de São Paulo, Faculdade de Odontologia, Departamento de Dentística, São Paulo, Brasil.
Background: Considering that a single passive application of hydrochloric acid (HCl) as a resin infiltration pretreatment can remove between 20 and 45 µm of enamel and cause etching that extends up to 2 mm beyond the white spot lesions (WSLs), it is plausible that its repeated and active applications could result in a greater amount of dental tissue being removed.
Objective: To evaluate the enamel surface loss and micromorphology after etching with 15% HCl using two application methods (passive-P and active-A) and varying numbers of applications (C-placebo - 120 s; 1x HCl - 120 s; 2x HCl - 120 s + 120 s; 3x HCl - 120 s + 120 s + 120 s).
Methodology: Bovine incisors with ≤0.
Materials (Basel)
August 2025
Department of Conservative Dentistry and Periodontology, Jena University Hospital, An der alten Post 4, 07743 Jena, Germany.
In adhesive dentistry, debonding-on-demand is attractive for situations where no permanent attachment is required. Due to its destructive nature, ultraviolet (UV) light may be of interest for attenuating bond forces. The aim of this study was to investigate the impact of UV light on the shear bond strength (SBS) of etch-and-rinse (n = 4) and universal adhesives (n = 3).
View Article and Find Full Text PDFJ Dent
August 2025
Department of Biological Sciences, Bauru School of Dentistry, University of São Paulo. Bauru-SP, Brazil. Electronic address:
Objectives: This study aimed to evaluate the antibacterial activity and anticariogenic effect of a hydroalcoholic extract of Matricaria chamomilla L., associated or not with fluoride, under a microcosm biofilm model.
Methods: Bovine enamel were divided into five groups (n = 12): (1) Fluoride, (2) M.
Am J Dent
August 2025
Department of Restorative Dentistry, Institute of Science and Technology, São Paulo State University- UNESP, São Paulo, Brazil,
Purpose: To evaluate the efficacy of low and high-concentrated bleaching gels in both at-home and in-office techniques and their effects on enamel properties.
Methods: Bovine enamel/dentin specimens were randomly allocated to five groups (n=12): deionized water (negative control - DW), 6% hydrogen peroxide (6HP), 40% hydrogen peroxide (40HP), 10% carbamide peroxide (10CP), and 45% carbamide peroxide (45CP). For 6HP and 40HP, the gel was applied 3x20 minutes in 1 day.
Dent J (Basel)
July 2025
Discipline of Dental Medicine, Faculty of Medicine and Pharmacy, University of Oradea, 410073 Oradea, Romania.
The rising demand for aesthetic dental treatments has spurred interest in peroxide-free color correctors as alternatives to traditional hydrogen peroxide formulations, which are associated with tooth sensitivity and potential enamel demineralization. This systematic review evaluates the whitening efficacy and safety profile of hydrogen peroxide-free color corrector (HPFCC) products, focusing on color change metrics, enamel and dentin integrity, and adverse effects. Following PRISMA guidelines, we searched PubMed, Scopus, and Web of Science throughout January 2025 for randomized controlled trials, observational studies, and in vitro experiments comparing HPFCC to placebo or peroxide-based agents.
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