Change in surface characteristics and permeability of human enamel after subjecting to radiation therapy.

Abstract

Radiation-related caries is a complex destructive lesion leading to uncompromising damage of enamel and dentin in patients suffering from head and neck cancer managed with radiotherapy. The purpose of this study was to evaluate the changes in the permeability of enamel and to assess the morphological and chemical changes of teeth surface subjected to 6 MV photon beam irradiation. For this in vitro study, coronal portion of 20 premolars were sectioned mesiodistally into halves and then grouped into two. Samples in group 1 (control) were not subjected to cycles of irradiation and those in group 2 (experimental) were subjected to a cumulative uniform radiation dose of 70 Gray fractioned in 35 fractions with 6 MV photons. The silver nitrate penetration method was used to assess the change in permeability of enamel. The variations in surface topography and mineral content were assessed using scanning electron microscopy with energy dispersive X-ray analysis. Dye penetration scores of surface texture changes were compared between the two groups utilizing the Chi-square test. The change in the elemental levels between enamel surfaces of the two groups was compared using an independent t-test. The application of 6 MV photon radiation did not change enamel permeability and surface topography. However, a noteworthy reduction in the carbon content (P = 0.002) was observed in teeth subjected to irradiation. Though radiation exposure did not alter the enamel permeability and surface topography, it had caused significant chemical compositional changes. Carbon content was significantly reduced in irradiated enamel samples.