IN SITU EFFECTS OF HEAD AND NECK RADIATION THERAPY ON MICROSTRUCTURE AND COMPOSITION OF HUMAN TEETH

Head and neck radiotherapy presents relevant collateral effects. This work aimed to evaluate possible in vivo compositional modifications through micro-X-ray fluorescence (m-XRF) and morphological changes through atomic force microscopy (AFM) and scanning electron microscopy (SEM) of enamel and dentin caused by radiation exposure related to head and neck cancer. Six well-preserved mandibular premolars with minimum structure loss were obtained from three patients who underwent radiotherapy. A control group with six mandibular premolars obtained from similar teeth extracted for periodontal indications was used to compare the analysis results. The compositional analysis considered the elements phosphorus (P), calcium (Ca), zinc (Zn), strontium (Sr), and the Ca/P ratio. Evaluations comprised the superficial enamel (SE), the enamel-dentin junction (EDJ), the medium dentin (MD), and deep dentin (DD). The compositional analysis considered the elements phosphorus (P), calcium (Ca), zinc (Zn), strontium (Sr), and the Ca/P ratio. The independent samples T-test was used to evaluate the compositional differences between the control and irradiated groups (P < .05). The results showed statistically significant differences considering Ca (EDJ, MD, and DD), Zn (SE), and Sr (SE, EDJ, and MD). The most noticeable morphological changes were in the superficial enamel. The results presented demonstrate significant changes in the irradiated teeth. These results encourage the search for methods to reduce the direct effects of radiation on the dental structure and the development of preventive intervention strategies that promote less damage.