A combination of scanning electrochemical cell microscopy (SECCM) and atomic force microscopy (AFM) is used to quantitatively study the acid-induced dissolution of dental enamel. A micron-scale liquid meniscus formed at the end of a dual barrelled pipette, which constitutes the SECCM probe, is brought into contact with the enamel surface for a defined period. Dissolution occurs at the interface of the meniscus and the enamel surface, under conditions of well-defined mass transport, creating etch pits that are then analysed via AFM. This technique is applied to bovine dental enamel, and the effect of various treatments of the enamel surface on acid dissolution (1mM HNO3) is studied. The treatments investigated are zinc ions, fluoride ions and the two combined. A finite element method (FEM) simulation of SECCM mass transport and interfacial reactivity, allows the intrinsic rate constant for acid-induced dissolution to be quantitatively determined. The dissolution of enamel, in terms of Ca(2+) flux ( [Formula: see text] ), is first order with respect to the interfacial proton concentration and given by the following rate law: [Formula: see text] , with k0=0.099±0.008cms(-1). Treating the enamel with either fluoride or zinc ions slows the dissolution rate, although in this model system the partly protective barrier only extends around 10-20nm into the enamel surface, so that after a period of a few seconds dissolution of modified surfaces tends towards that of native enamel. A combination of both treatments exhibits the greatest protection to the enamel surface, but the effect is again transient.
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http://dx.doi.org/10.1016/j.jcis.2016.05.018 | DOI Listing |
Lasers Med Sci
January 2025
Department of Stomatology, the First Medical Centre, Chinese PLA General Hospital, Beijing, 100853, China.
Objective: This study evaluated dentin morphology and pulp cavity temperature changes during nanosecond‑ and microsecond‑pulse Er, Cr: YSGG laser debonding restoration and residual adhesive.
Materials And Methods: Ten caries-free teeth had their enamel removed perpendicular to the long axis, followed by bonding of glass ceramic restorations. The samples were randomly divided into two groups and subjected to Er, Cr: YSGG laser (3 mJ, 100 Hz, 100 ns), (3 mJ, 100 Hz, 150 µs) for debonding of restoration and residual adhesive on dentin surfaces.
J Contemp Dent Pract
September 2024
Department of Orthodontic, Faculty of Dentistry, Mansoura University, Mansoura, Egypt.
Aim: This study evaluates long-term shear bond strength (SBS) and enamel micro cracks (MCs) healing after using adhesive pre-coated brackets (APC).
Materials And Methods: A total of eighty extracted human premolar teeth were randomly divided into four experimental groups ( = 20 per group): Control group: Teeth underwent indentation but no bracket bonding; group II : Teeth were subjected to indentation without exposure to thermocycling; group III: Teeth experienced both indentation and thermocycling; group IV: No indentation was applied to the teeth; groups III and IV were further divided into two subgroups to simulate different clinical timelines: Subgroup A (n = 10): Teeth underwent 5,000 thermocycles, equivalent to six months of clinical use. Subgroup B (n = 10): Teeth were subjected to 10,000 thermocycles, representing 12 months of use.
BMC Oral Health
January 2025
Department of Operative Dentistry, Faculty of Dentistry, Chulalongkorn University, Bangkok, Thailand.
Background: This in vitro study evaluated the efficacy of professional and home-use fluoride regimens for protecting irradiated enamel, undergoing pH cycling resembling xerostomia.
Methods: Sixty human premolar teeth were irradiated with a total dose of 70 Gy and subsequently sectioned into 3 × 3 cm enamel slabs. These slabs were randomly distributed into five groups (n = 12 per group): professional-use groups received fluoride varnish either weekly (FV1) or biweekly (FV2); home-use groups applied 5000 ppm (FT5) or 1450 ppm (FT) fluoride toothpaste; and a control group (control) received no treatment.
Morphologie
January 2025
Department of Biostatistics, KS Hegde Medical Academy, Nitte (deemed to be university), Mangalore, Karnataka, India.
Introduction: In the forensic field, having accurate understanding of the macroscopic and microscopic alterations that occur in teeth when exposed to temperatures has remarkable significance. The preservation of delicate incinerated teeth is crucial in fire investigations that pertain to the temperature exposed, as well as the identification of victims. This preservation is necessary in order to conduct macroscopic and microscopic ultra-structural examinations, which provide valuable insights into the structural alterations that dental tissues undergo when exposed to low to high temperatures.
View Article and Find Full Text PDFRegen Biomater
November 2024
National Engineering Research Center for Biomaterials, Sichuan University, Chengdu 610064, China.
Nanohydroxyapatite (nHA) is distinguished by its exceptional biocompatibility, bioactivity and biodegradability, qualities attributed to its similarity to the mineral component of human bone. This review discusses the synthesis techniques of nHA, highlighting how these methods shape its physicochemical attributes and, in turn, its utility in biomedical applications. The versatility of nHA is further enhanced by doping with biologically significant ions like magnesium or zinc, which can improve its bioactivity and confer therapeutic properties.
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