The damage and remineralization strategies of dental hard tissues following radiotherapy

Abstract

Objectives: This study pursued two main purposes. The first aim was to expound on the microscopic factors of radiation-related caries (RRC). Further, it aimed to compare the remineralization effect of different remineralizing agents on demineralized teeth after radiotherapy.

Methods: The enamel and dentin samples of bovine teeth were irradiated with different doses of radiation. After analysis of scanning electron microscope (SEM), X-Ray diffraction (XRD), and energy dispersive spectrometer (EDS), the samples irradiated with 50 Gy radiation were selected and divided into the demineralization group, the double distilled water (DDW) group, the Sodium fluoride (NaF) group, the Casein phosphopeptide-amorphous calcium phosphate (CPP-ACP) group, the NaF + CPP-ACP group, and the Titanium tetrafluoride (TiF₄) group. After demineralization, remineralizing agents treatment, and remineralization, the samples were evaluated using SEM, atomic force microscope (AFM), EDS, and transverse microradiography (TMR).

Results: A radiation dose of 30 Gy was sufficient to cause damage to the dentinal tubules, but 70 Gy radiation had little effect on the microstructure of enamel. Additionally, the NaF + CPP-ACP group and the TiF₄ group significantly promoted deposit formation, decreased surface roughness, and reduced mineral loss and lesion depth of demineralized enamel and dentin samples after radiation.

Conclusions: Radiation causes more significant damage to dentin compared to enamel. NaF + CPP-ACP and TiF₄ had a promising ability to promote remineralization of irradiated dental hard tissues.

Advances in knowledge: This in vitro study contributes to determining a safer radiation dose range for teeth and identifying the most effective remineralization approach for RRC.

Keywords: Casein phosphopeptide-amorphous calcium phosphate; Dental hard tissue remineralization; Radiation-related caries; Radiotherapy; Titanium tetrafluoride.

Fig. 1

The flowchart of the experimental procedure

Fig. 2

(A) Representative microstructure of enamel and (B) dentin after different doses of radiation (SEM images, 5000 × and 40,000 ×). (C) Representative longitudinal section of dentin after different doses of irradiation (SEM images, 40,000 ×). The red arrows indicate typical collagen fiber morphology

Fig. 3

(A) The XRD phase analysis of enamel after different doses of radiation. (B) The content of Ca, P, and C elements in enamel and (C) dentin at different depths under different radiation doses

Fig. 4

(A) Representative AFM images of enamel and (B) dentin surfaces in each group. (C) Representative SEM image of enamel in each group (5000 ×). (D) Representative SEM image of dentin in each group (5000 × and 40,000 ×)

Fig. 5

(A) The changes of Ca, P, F, and Ti elements content in irradiated enamel and (B) dentin at different depths after being treated with different remineralizing agents. (C) TMR images of demineralized enamel and (D) dentin treated with different remineralizing agents