Radiation therapy

Radiation directed at the oral cavity or surrounding structures increases the risk of dental anomalies because ameloblasts can be permanently damaged by doses as low as 10 Gy. In addition, salivary function is impacted by exposure to major and minor glands.[3-5]

The most significant degree of tooth aplasia or delayed eruption occurs in younger children (aged <4 years) who are exposed to radiation doses of 20 Gy or higher.[13]

Developing teeth may be irradiated when treating head and neck sarcomas, Hodgkin lymphoma, neuroblastoma, central nervous system leukemia, nasopharyngeal cancer, and brain tumors, or during total-body irradiation (TBI) for HSCT.

Doses of 10 Gy to 40 Gy can cause root shortening or abnormal curvature, dwarfism, and hypocalcification.[14]

Significant dental abnormalities, including mandibular or maxillary hypoplasia, increased caries, hypodontia, microdontia, root stunting, and xerostomia have been reported in more than 85% of survivors of head and neck rhabdomyosarcoma treated with radiation doses higher than 40 Gy.[4,15]

In the St. Jude Life (SJLIFE) cohort, survivors who received radiation therapy that potentially exposed the oral cavity were more likely to report at least one dental health problem (odds ratio [OR], 1.48; 95% confidence interval [CI], 1.26–1.72) and at least one soft tissue abnormality (OR, 1.52; 95% CI, 1.25–1.84) after controlling for socioeconomic factors, age at last follow-up and diagnosis, other treatment exposures, and access to dental services.[12]