SURFACE COMPOSITION AND NANO-MECHANICAL PROPERTIES OF HUMAN ENAMEL BRUSHED WITH TOOTHPASTE STANDARDIZED BY 10 WT % NANO-HYDROXYAPATITE | ||||
| Egyptian Dental Journal | ||||
| Article 17, Volume 63, Issue 3 - July (Fixed Prosthodontics, Dental Materials, Conservative Dentistry & Endodontics), July 2017, Page 2607-2617 PDF (1.59 MB) | ||||
| Document Type: Original Article | ||||
| DOI: 10.21608/edj.2017.76212 | ||||
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| Authors | ||||
| Dalia M Abdel-Hamid1; Norhan A El-Dokky2; Sherif B El-Tawil2 | ||||
| 1Assistant Professor of Dental Materials Science, Biomaterials Department, Faculty of Dentistry, Cairo University, Egypt. | ||||
| 2Assistant Professor of Pedodontics, Pediatric and Community Dentistry Department, Faculty of Dentistry, Cairo University, Egypt | ||||
| Abstract | ||||
| Purpose: Evaluation of the effect of simulated brushing with toothpaste standardized by 10 wt. % nano-hydroxyapatite (n-HAp) for one year on the surface composition and nano-mechanical properties (hardness and elastic modulus) of human enamel. Study design: 20 sliced human enamel/dentin slabs were divided into: control group (brushed with a commercial toothpaste) and test group (brushed with the same toothpaste with 10 wt. % n-HAp ~20 nm). Brushing was performed for one hour/day for 24 days. The nano-hardness and elastic modulus were measured (GPa) by the nano-indenter. SEM and EDXA were performed to study the morphology, thickness and the chemical composition of enamel surface. The Ca/P ratio was calculated (at. %). The data were statistically analyzed. Results: Insignificant difference (P = 0.070) between the nanohardness values of the 2 groups was obtained. However, the elastic modulus of the control group was significantly lower than that of the test group (P = 0.019). SEM of the test group revealed the precipitation of n-HAp layer (~5 µm thick). The Ca/P ratios and the other minerals of the two groups were not significantly different. Conclusions: Using dental products containing ≥10 wt. % n-AHp should be restricted to patients susceptible to demineralization; to avoid their detrimental effect on the elastic modulus that could be negatively reflected clinically on the mechanical behavior of the teeth. | ||||
| Keywords | ||||
| Surface composition; Nano-mechanical; enamel; nano-hydroxyapatite; Brushing; Toothpaste | ||||
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