Rafael Resende de Miranda1, Anielle Christine Almeida Silva2, Noelio Oliveira Dantas2, Carlos José Soares1, Veridiana Resende Novais3. 1. Department of Operative Dentistry and Dental Materials, School of Dentistry, Federal University of Uberlândia, Av Pará 1720, Block 4L, room A32, Campus Umuarama, Uberlândia, Minas Gerais, 38405-320, Brazil. 2. Laboratory of New Nanostructured and Functional Materials, Institute of Physics, Federal University of Alagoas, Av Lourival Melo Mota S/N, Campus A. C. Simões, Maceió, Alagoas, 57072-970, Brazil. 3. Department of Operative Dentistry and Dental Materials, School of Dentistry, Federal University of Uberlândia, Av Pará 1720, Block 4L, room A32, Campus Umuarama, Uberlândia, Minas Gerais, 38405-320, Brazil. veridianaresende@hotmail.com.
Abstract
OBJECTIVES: To evaluate the effect of in vivo radiotherapy on the chemical properties of human dentine by Fourier-transform infrared spectroscopy (FTIR) and Raman analysis. MATERIALS AND METHODS: Chemical composition was evaluated comparing control and irradiated group (n = 8). Irradiated teeth were obtained from radiotherapy patients subjected to fractionated X-ray radiation of 1.8 Gy daily totaling 72 Gy. The teeth were sectioned according to the type of dentine (crown or root dentine), obtaining 3-mm dentine cervical slices. The analyzed parameters by FTIR and Raman spectroscopies were mineral/matrix ratio (M:M), carbonate/mineral ratio (C:M), amide I/amide III ratio, and amide I/CH2 ratio. Raman also calculated the phosphate and carbonate crystallinity. RESULTS: FTIR revealed that M:M had a decrease in both factors (p = 0.008; p = 0.043, respectively) and root dentine showed a lower C:M in the irradiated group (p = 0.003). Raman revealed a higher phosphate crystallinity and a lower carbonate crystallinity in crown dentine of irradiated group (p = 0.021; p = 0.039). For amide I/amide III, the irradiated showed a lower ratio when compared to the control group (FTIR p = 0.002; Raman p = 0.017). For amide I/CH2, the root dentine showed a higher ratio than the crown dentine in both methods (p < 0.001). CONCLUSIONS: Radiotherapy altered the chemical composition of human dentine. The exchange of phosphate-carbonate ions in the hydroxyapatite and higher concentration of organic components was found after radiotherapy. CLINICAL RELEVANCE: The increased risk of radiation-related caries in patients undergoing head and neck radiotherapy is due not only to salivary, dietary, and microbiological changes but also to changes in tooth chemical composition.
OBJECTIVES: To evaluate the effect of in vivo radiotherapy on the chemical properties of human dentine by Fourier-transform infrared spectroscopy (FTIR) and Raman analysis. MATERIALS AND METHODS: Chemical composition was evaluated comparing control and irradiated group (n = 8). Irradiated teeth were obtained from radiotherapy patients subjected to fractionated X-ray radiation of 1.8 Gy daily totaling 72 Gy. The teeth were sectioned according to the type of dentine (crown or root dentine), obtaining 3-mm dentine cervical slices. The analyzed parameters by FTIR and Raman spectroscopies were mineral/matrix ratio (M:M), carbonate/mineral ratio (C:M), amide I/amide III ratio, and amide I/CH2 ratio. Raman also calculated the phosphate and carbonate crystallinity. RESULTS: FTIR revealed that M:M had a decrease in both factors (p = 0.008; p = 0.043, respectively) and root dentine showed a lower C:M in the irradiated group (p = 0.003). Raman revealed a higher phosphate crystallinity and a lower carbonate crystallinity in crown dentine of irradiated group (p = 0.021; p = 0.039). For amide I/amide III, the irradiated showed a lower ratio when compared to the control group (FTIR p = 0.002; Raman p = 0.017). For amide I/CH2, the root dentine showed a higher ratio than the crown dentine in both methods (p < 0.001). CONCLUSIONS: Radiotherapy altered the chemical composition of human dentine. The exchange of phosphate-carbonate ions in the hydroxyapatite and higher concentration of organic components was found after radiotherapy. CLINICAL RELEVANCE: The increased risk of radiation-related caries in patients undergoing head and neck radiotherapy is due not only to salivary, dietary, and microbiological changes but also to changes in tooth chemical composition.
Entities:
Keywords:
Dentine; Fourier-transform infrared spectroscopy; Head and neck cancer; Radiotherapy; Raman spectroscopy
Authors: C J Soares; C G Castro; N A Neiva; P V Soares; P C F Santos-Filho; L Z Naves; P N R Pereira Journal: J Dent Res Date: 2009-12-30 Impact factor: 6.116
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