Susceptibility of gamma-irradiated primary teeth to a cariogenic challenge: an in vitro study

This study aimed to evaluate whether radiotherapy with gamma radiation changes the susceptibility of primary teeth to a cariogenic challenge.

Specimens of primary teeth (n = 18) were subjected to gamma radiation simulating the radiotherapy treatment, and 18 specimens were used as control group. A microbiological model of caries induction by S. mutans was used to evaluate the susceptibility of these irradiated specimens to the caries development. The depth, area and volume of caries lesion formed were evaluated using microcomputer tomography analysis (μ-CT) and changes occurring on the enamel surface were evaluated using scanning electron microscopy (SEM). Data of the lesion depth, lesion area and volume were submitted to independent t test with a 5% of significance limit.

The lesion depth and the area of caries in the irradiated group (196.61 ± 60.41 µm and 564.52 ± 343.37 µm², respectively) were significantly higher (p = 0.02 and p = 0.03, respectively) than those in the nonirradiated group (151.70 ± 32.16 µm and 386.64 ± 169.75 µm², respectively). However, the lesion volume did not differ (p = 0.15) between the groups (7797.89 ± 3675.69 µm³ for irradiated and 6509.03 ± 2902.65 µm³ for nonirradiated group). The SEM images show greater enamel breakdown in the group of irradiated specimens.

The present study results reveal that the gamma radiation protocol used for cancer treatment renders primary teeth more susceptible to a cariogenic challenge.