title: Effect of gamma irradiation on the wear behaviour of human tooth enamel.
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.
authors.affiliation: State Key Laboratory of Oral Diseases, West China Hospital of Stomatology, Sichuan University, Chengdu, PR China.
authors.forename: Ping
authors.initials: P
authors.lastname: Qing
authors.affiliation: Department of Prosthodontics, School and Hospital of Stomatology, Wenzhou Medical University, Wenzhou, PR China.
authors.forename: Shengbin
authors.initials: S
authors.lastname: Huang
authors.affiliation: State Key Laboratory of Oral Diseases, West China Hospital of Stomatology, Sichuan University, Chengdu, PR China.
authors.forename: ShanShan
authors.initials: S
authors.lastname: Gao
authors.affiliation: Tribology Research Institute, National Traction Power Laboratory, Southwest Jiaotong University, Chengdu, PR China.
authors.forename: LinMao
authors.initials: L
authors.lastname: Qian
authors.affiliation: State Key Laboratory of Oral Diseases, West China Hospital of Stomatology, Sichuan University, Chengdu, PR China.
authors.forename: HaiYang
authors.initials: H
authors.lastname: Yu
mesh_terms: D003460:Crystallization; D003743:Dental Enamel / Q000528:radiation effects*; D017276:Friction; D005720:Gamma Rays; D006244:Hardness; D006801:Humans; D017550:Spectroscopy, Fourier Transform Infrared; D014070:Tooth / Q000528:radiation effects*; D014961:X-Ray Diffraction