Long-Term Effects of Exposure to Ionizing Irradiation on Periodontal Health Status – The Tinea capitis Cohort Study

Abstract

Studies among long-term survivors of childhood cancer who had received high-dose irradiation therapy of 4–60 Gy, demonstrated acute and chronic dental effects, including periodontal diseases. However, the possible effects of low to moderate doses of radiation on dental health are sparse. The aim of this study is to investigate the association between childhood exposure to low–moderate doses of ionizing radiation and periodontal health following 50 years since exposure. The study population included 253 irradiated subjects (treated for Tinea capitis in the 1950s) and, 162 non-irradiated subjects. The estimated dose to the teeth was 0.2–0.4 Gy. Dental examination was performed according to the community periodontal index (CPI). Socioeconomic and health behavior variables were obtained through a personal questionnaire. Periodontal disease was operationally defined as “deep periodontal pockets.” A multivariate logistic regression model was used for the association of irradiation status and other independent variables with periodontal status. The results showed that among the irradiated subjects, 23%, (95% CI 18–28%) demonstrated complete edentulousness or insufficient teeth for CPI scoring as compared to 13% (95% CI 8–19%) among the non-irradiated subjects (p = 0.01). Periodontal disease was detected among 54% of the irradiated subjects as compared to 40% of the non-irradiated (p = 0.008). Controlling for education and smoking, the ORs for the association between radiation and periodontal disease were 1.61 (95% CI 1.01–2.57) and 1.95 (95% CI 1.1–3.5) for ever never and per 1 Gy absorbed in the salivary gland, respectively. In line with other studies, a protective effect for periodontal diseases among those with high education and an increased risk for ever smokers were observed. In conclusion, childhood exposure to low-moderate doses of ionizing radiation might be associated with later outcomes of dental health. The results add valuable data on the long-term health effects of exposure to ionizing radiation and support the implementation of the ALARA principle in childhood exposure to diagnostic procedure involving radiation.

Caries Experience among Adults Exposed to Low to Moderate Doses of Ionizing Radiation in Childhood – The Tinea Capitis Cohort

“…Exclusion criteria included death and medical conditions that did not allow an interview such as mental disease. The sample of individuals who comply with these eligibility criteria included 827 individuals (426 irradiated and 401 non-exposed population controls)” ( 16 ). Of them, “20% ( n = 171) could not participate in the study due to unavailable addresses and 415 individuals were interviewed (79 and 48% of the traceable irradiated and non-irradiated groups respectively).…”

“…Participants and non-participants of each study group did not differ significantly by gender and place of birth, and by age in the irradiated group. Participants of the non-irradiated group tended to be slightly younger than non-participants (mean ages 58 vs. 59 years, respectively; p = 0.02)” ( 16 ).…”

“…Prior to irradiation, the subject’s hair was shaved and remaining hair was removed by a waxing process. In the 1960s, dosimetry was estimated retrospectively using one of the original X-ray machines and a specially designed head phantom” ( 16 ). In the 1980s, individual average doses to different organs were estimated for each irradiated case.…”

“…The mean average doses for all irradiated individuals were 1.5, 0.09, and 0.78 Gy to the brain, thyroid and parotid glands respectively ( 7 ). The estimated dose to the teeth ranged between 0.2 to 0.4 Gy, with the higher dose to the posterior molars” ( 16 ).…”

“…“Between 1946 and 1960, about 20,000 Israeli children were treated with IR to the head for tinea capitis (TC), a benign fungal disease of the scalp” ( 14 – 16 ). “In 1968, a comprehensive follow-up of a cohort including the irradiated group and two comparison groups was initiated to determine possible delayed side effects of irradiation” ( 16 – 18 ). The aim of the present study was to assess the association of childhood exposure to low–moderate doses of IR on dental caries cumulative experience.…”