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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

Tribological properties of enamel before and after irradiation.SEM images of scratches in the perpendicular-sectioned enamel slides before and after irradiation, subjected to different normal loads: (a1) Fn = 20 mN before irradiation; (a2) Fn = 20 mN after irradiation; (a3) Fn = 40 mN before irradiation; (a4) Fn = 40 mN after irradiation; (a5) Fn = 60 mN before irradiation; (a6) Fn = 60 mN after irradiation; (a7) Fn = 80 mN before irradiation; and (a8) Fn = 80 mN after irradiation. SEM images of parallel-sectioned enamel slides before and after irradiation, subjected to different normal loads: (b1) Fn = 20 mN before irradiation; (b2) Fn = 20 mN after irradiation; (b3) Fn = 40 mN before irradiation; (b4) Fn = 40 mN after irradiation; (b5) Fn = 60 mN before irradiation; (b6) Fn = 60 mN after irradiation; (b7) Fn = 80 mN before irradiation; and (b8) Fn = 80 mN after irradiation.
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f1: Tribological properties of enamel before and after irradiation.SEM images of scratches in the perpendicular-sectioned enamel slides before and after irradiation, subjected to different normal loads: (a1) Fn = 20 mN before irradiation; (a2) Fn = 20 mN after irradiation; (a3) Fn = 40 mN before irradiation; (a4) Fn = 40 mN after irradiation; (a5) Fn = 60 mN before irradiation; (a6) Fn = 60 mN after irradiation; (a7) Fn = 80 mN before irradiation; and (a8) Fn = 80 mN after irradiation. SEM images of parallel-sectioned enamel slides before and after irradiation, subjected to different normal loads: (b1) Fn = 20 mN before irradiation; (b2) Fn = 20 mN after irradiation; (b3) Fn = 40 mN before irradiation; (b4) Fn = 40 mN after irradiation; (b5) Fn = 60 mN before irradiation; (b6) Fn = 60 mN after irradiation; (b7) Fn = 80 mN before irradiation; and (b8) Fn = 80 mN after irradiation.

Mentions: Figure 1a1-1a8 shows scanning electron microscopy (SEM) images of typical nanoscratch traces at different normal loads in perpendicular-sectioned enamel before and after irradiation. Distinct differences existed between the scratch morphologies of the enamel before and after irradiation. At a load of 20 mN, the grooves of the enamel both before (Fig. 1a1) and after irradiation (Fig. 1a2) were very shallow, and no obvious plastic deformation occurred. When the load was increased to 40 mN, a groove with clear edges became apparent due to significant plastic deformation. Meanwhile, no debris was found before irradiation (Fig. 1a3), while an obvious scratch with a small amount of debris at the edges of the scratch trace appeared after irradiation (Fig. 1a4). Under a load of 60 mN, a little debris accumulated at one edge of the scratch trace before irradiation (Fig. 1a5), whereas greater debris accumulated on edges along the length of the scratch traces after irradiation (Fig. 1a6). At the end of the scratch, more partial packing occurred with an increase in the load prior to irradiation (Fig. 1a7), and delaminations were observed at the edge of the scratch after irradiation (Fig. 1a8).


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)

Tribological properties of enamel before and after irradiation.SEM images of scratches in the perpendicular-sectioned enamel slides before and after irradiation, subjected to different normal loads: (a1) Fn = 20 mN before irradiation; (a2) Fn = 20 mN after irradiation; (a3) Fn = 40 mN before irradiation; (a4) Fn = 40 mN after irradiation; (a5) Fn = 60 mN before irradiation; (a6) Fn = 60 mN after irradiation; (a7) Fn = 80 mN before irradiation; and (a8) Fn = 80 mN after irradiation. SEM images of parallel-sectioned enamel slides before and after irradiation, subjected to different normal loads: (b1) Fn = 20 mN before irradiation; (b2) Fn = 20 mN after irradiation; (b3) Fn = 40 mN before irradiation; (b4) Fn = 40 mN after irradiation; (b5) Fn = 60 mN before irradiation; (b6) Fn = 60 mN after irradiation; (b7) Fn = 80 mN before irradiation; and (b8) Fn = 80 mN after irradiation.
© Copyright Policy - open-access
Related In: Results  -  Collection

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

f1: Tribological properties of enamel before and after irradiation.SEM images of scratches in the perpendicular-sectioned enamel slides before and after irradiation, subjected to different normal loads: (a1) Fn = 20 mN before irradiation; (a2) Fn = 20 mN after irradiation; (a3) Fn = 40 mN before irradiation; (a4) Fn = 40 mN after irradiation; (a5) Fn = 60 mN before irradiation; (a6) Fn = 60 mN after irradiation; (a7) Fn = 80 mN before irradiation; and (a8) Fn = 80 mN after irradiation. SEM images of parallel-sectioned enamel slides before and after irradiation, subjected to different normal loads: (b1) Fn = 20 mN before irradiation; (b2) Fn = 20 mN after irradiation; (b3) Fn = 40 mN before irradiation; (b4) Fn = 40 mN after irradiation; (b5) Fn = 60 mN before irradiation; (b6) Fn = 60 mN after irradiation; (b7) Fn = 80 mN before irradiation; and (b8) Fn = 80 mN after irradiation.
Mentions: Figure 1a1-1a8 shows scanning electron microscopy (SEM) images of typical nanoscratch traces at different normal loads in perpendicular-sectioned enamel before and after irradiation. Distinct differences existed between the scratch morphologies of the enamel before and after irradiation. At a load of 20 mN, the grooves of the enamel both before (Fig. 1a1) and after irradiation (Fig. 1a2) were very shallow, and no obvious plastic deformation occurred. When the load was increased to 40 mN, a groove with clear edges became apparent due to significant plastic deformation. Meanwhile, no debris was found before irradiation (Fig. 1a3), while an obvious scratch with a small amount of debris at the edges of the scratch trace appeared after irradiation (Fig. 1a4). Under a load of 60 mN, a little debris accumulated at one edge of the scratch trace before irradiation (Fig. 1a5), whereas greater debris accumulated on edges along the length of the scratch traces after irradiation (Fig. 1a6). At the end of the scratch, more partial packing occurred with an increase in the load prior to irradiation (Fig. 1a7), and delaminations were observed at the edge of the scratch after irradiation (Fig. 1a8).

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