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Effect of gamma irradiation on the wear behaviour of human tooth enamel.

Qing P, Huang S, Gao S, Qian L, Yu H - Sci Rep (2015)

Bottom Line: Surface microhardness (SMH) alteration was also evaluated.An inferior nanoscratch resistance was observed independent of prism orientation.Moreover, the variation of wear behaviours was closely related to changes in the crystallography, chemical composition and SMH of the enamel.

View Article: PubMed Central - PubMed

Affiliation: State Key Laboratory of Oral Diseases, West China Hospital of Stomatology, Sichuan University, Chengdu, PR China.

ABSTRACT
Radiotherapy is a frequently used treatment for oral cancer. Extensive research has been conducted to detect the mechanical properties of dental hard tissues after irradiation at the macroscale. However, little is known about the influence of irradiation on the tribological properties of enamel at the micro- or nanoscale. Therefore, this study aimed to investigate the effect of gamma irradiation on the wear behaviour of human tooth enamel in relation to prism orientation. Nanoscratch tests, surface profilometer and scanning electron microscope (SEM) analysis were used to evaluate the friction behaviour of enamel slabs before and after treatment with identical irradiation procedures. X-ray diffraction (XRD) and Fourier transform infrared spectroscopy (FTIR) were performed to analyse the changes in crystallography and chemical composition induced by irradiation. Surface microhardness (SMH) alteration was also evaluated. The results showed that irradiation resulted in different scratch morphologies, friction coefficients and remnant depth and width at different loads. An inferior nanoscratch resistance was observed independent of prism orientation. Moreover, the variation of wear behaviours was closely related to changes in the crystallography, chemical composition and SMH of the enamel. Together, these measures indicated that irradiation had a direct deleterious effect on the wear behaviour of human tooth enamel.

No MeSH data available.


Related in: MedlinePlus

Specimen preparation.The cutting directions were adjusted to make the testing surface perpendicular (a) or parallel (b) to the direction of the enamel rod.
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f4: Specimen preparation.The cutting directions were adjusted to make the testing surface perpendicular (a) or parallel (b) to the direction of the enamel rod.

Mentions: A total of nineteen human teeth were used in this study. Enamel slides were sectioned from each tooth using a diamond-coated band saw (Minitom; Struers, Copenhagen, Denmark) under running water. The cutting direction was adjusted to be perpendicular (2 slides) or parallel (2 slides) to the direction of the enamel rod (Fig. 4). Thirteen human teeth were randomly selected for scratch resistance and microhardness testing. These enamel blocks were embedded using polymethyl methacrylate, with a 2 mm × 2 mm exposure window for treatment. Another six human teeth, not imbedded in polymethyl methacrylate, were prepared for XRD and FTIR analysis. All of the specimens were first ground using silicon carbide papers (500, 800, 1,200, 2,000, 3,000, or 4,000 grit) in sequence and then polished with diamond paste of 10, 5, or 2.5 μm in turn. Grinding and polishing were conducted under water-cooling conditions in order to avoid the dehydration caused by local overheating. All of the specimens were then washed ultrasonically for 10 min with distilled water to remove debris, according to the method described in our previous studies1032.


Effect of gamma irradiation on the wear behaviour of human tooth enamel.

Qing P, Huang S, Gao S, Qian L, Yu H - Sci Rep (2015)

Specimen preparation.The cutting directions were adjusted to make the testing surface perpendicular (a) or parallel (b) to the direction of the enamel rod.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4477323&req=5

f4: Specimen preparation.The cutting directions were adjusted to make the testing surface perpendicular (a) or parallel (b) to the direction of the enamel rod.
Mentions: A total of nineteen human teeth were used in this study. Enamel slides were sectioned from each tooth using a diamond-coated band saw (Minitom; Struers, Copenhagen, Denmark) under running water. The cutting direction was adjusted to be perpendicular (2 slides) or parallel (2 slides) to the direction of the enamel rod (Fig. 4). Thirteen human teeth were randomly selected for scratch resistance and microhardness testing. These enamel blocks were embedded using polymethyl methacrylate, with a 2 mm × 2 mm exposure window for treatment. Another six human teeth, not imbedded in polymethyl methacrylate, were prepared for XRD and FTIR analysis. All of the specimens were first ground using silicon carbide papers (500, 800, 1,200, 2,000, 3,000, or 4,000 grit) in sequence and then polished with diamond paste of 10, 5, or 2.5 μm in turn. Grinding and polishing were conducted under water-cooling conditions in order to avoid the dehydration caused by local overheating. All of the specimens were then washed ultrasonically for 10 min with distilled water to remove debris, according to the method described in our previous studies1032.

Bottom Line: Surface microhardness (SMH) alteration was also evaluated.An inferior nanoscratch resistance was observed independent of prism orientation.Moreover, the variation of wear behaviours was closely related to changes in the crystallography, chemical composition and SMH of the enamel.

View Article: PubMed Central - PubMed

Affiliation: State Key Laboratory of Oral Diseases, West China Hospital of Stomatology, Sichuan University, Chengdu, PR China.

ABSTRACT
Radiotherapy is a frequently used treatment for oral cancer. Extensive research has been conducted to detect the mechanical properties of dental hard tissues after irradiation at the macroscale. However, little is known about the influence of irradiation on the tribological properties of enamel at the micro- or nanoscale. Therefore, this study aimed to investigate the effect of gamma irradiation on the wear behaviour of human tooth enamel in relation to prism orientation. Nanoscratch tests, surface profilometer and scanning electron microscope (SEM) analysis were used to evaluate the friction behaviour of enamel slabs before and after treatment with identical irradiation procedures. X-ray diffraction (XRD) and Fourier transform infrared spectroscopy (FTIR) were performed to analyse the changes in crystallography and chemical composition induced by irradiation. Surface microhardness (SMH) alteration was also evaluated. The results showed that irradiation resulted in different scratch morphologies, friction coefficients and remnant depth and width at different loads. An inferior nanoscratch resistance was observed independent of prism orientation. Moreover, the variation of wear behaviours was closely related to changes in the crystallography, chemical composition and SMH of the enamel. Together, these measures indicated that irradiation had a direct deleterious effect on the wear behaviour of human tooth enamel.

No MeSH data available.


Related in: MedlinePlus