Effect of radiation on microhardness and ultramorphological changes in dentin - An in vitro analysis

Radiation therapy, which is frequently used to treat head-and-neck cancers, significantly alters the characteristics of dentin, making it more vulnerable to radiation caries.

To analyse the effect of radiation on microhardness and morphology of dentin.

After obtaining the Institutional ethical clearance (Nu/CEC/BRNS-01/2015), 40 freshly extracted molar teeth were obtained from the Department of Oral and Maxillofacial Surgery at the A. B. Shetty Memorial Institute of Dental Sciences, Mangalore. The teeth were disinfected and cleaned as per Occupational Safety and Health Administration regulations. The tooth samples were stored in distilled water at 4°C-8°C for further use. The roots of the tooth were removed and bisected longitudinally in mesiodistal direction using carborundum disc and a micromotor. The dentin's microhardness and Scanning Electron Microscopy (SEM) were examined before and after radiation.

Following radiation, the microhardness of the superficial, intermediate, and deep dentin significantly decreased (P < 0.001). Dentin tubule loss following radiation was revealed by the SEM analysis.

The radiation treatment decreases the microhardness of the dentin. 70 Gy radiation is damaging to dental tissues and can cause radiation caries. Damage to collagen fibrils causes changes in dentin, which significantly lowers the hardness and stability of dentin and lowers the microhardness of superficial, intermediate, and deep dentin. The SEM analysis showed the total destruction of tubule morphology postradiation.