Background and objectives : Radiation-related caries (radiation caries) is a frequently complication of patients with radiotherapy in the head and neck region. The aim of this study is to investigate the crystallinity of the mineral part of the irradiated teeth by Raman spectroscopy.

Methods : Two extracted third molar from patients with/without radiotherapy (total dosage of 65 Gy) were collected. We use a micro-Raman spectroscopy with a spatial resolution of 1 μm; the beam was focus on occlusive enamel, bacterial infected enamel, and dentin regions of both radiated and controlled samples. The Knoop¡¦s microhardness were measured on occlusive enamel samples ( n = 13) using a Matsuzausa MXT 70 at a load of 500 g for 15 s.

Results : The Raman main band positions (in cm ⁻¹ ) of enamel are identified as v2 PO43-(432), £h2 PO43-(450, 588, 608), £h1 PO43-(960), £h3 PO43-(1030, 1046, 1071), B type £h1 CO32-(1069), and A type £h1 CO32-(1102) which were similar to previous studies. After t -test analysis, we found that there is no significant difference between the mean values of microhardness (KHN) of radiated enamel (247.3¡Ó17.3) and controlled enamel (239.3¡Ó10.5).

Conclusions : The micro-Raman spectrums show that the radiation damage may have an effect on the crystal integrity of the enamel and dentine.