Abstract
Objectives Teeth exposed to therapeutic radiation have an increased susceptibility to a highly destructive form of dental disease. As part of a 5-year investigation, the overall goal is to analyze predictors of the severity of postradiation dental lesions and potentially determine if there is a link between postradiation dental lesions and radiation dose.
Methods During year 1 of the investigation, 21 subjects who had received head and neck radiotherapy were evaluated concerning individual tooth-level radiation dose, elapsed time after radiation, frequency of topical fluoride, xerostomia, and oral hygiene status. Subjects' teeth were also evaluated using an index developed to assess postradiation tooth destruction and associated restorations. Tooth destruction was operationalized as a mean tooth surface score (MSS). Tooth restoration was operationalized in a similar manner as a mean restoration score (MRS). Descriptive statistics were used to characterize the subject population. To account for the nesting of teeth within individuals and account for radiation dose varying for different teeth within individuals, multivariate analysis was conducted using generalized estimating equations, with exchangeable working matrices and robust standard errors. A significance level of p ≤ .05 was used.
Results Subjects (6 females, 15 males), most of whom reported xerostomia, ranged in age from 18 to 82 years. Four hundred seventeen teeth were evaluated. Elapsed time since radiation varied from 1 to 133 months; individual tooth-level radiation doses ranged from 0 to 69 Gy. Results showed that there were significant interaction effects of elapsed time*radiation dose, elapsed time*oral hygiene, elapsed time*fluoride, fluoride*oral hygiene, and oral hygiene*radiation dose, as well as main effects of radiation dose, xerostomia, oral hygiene, and fluoride frequency on tooth destruction (MSS). In contrast, only elapsed time and time*oral hygiene had a significant effect on the restoration score (MRS).
Conclusions The preliminary evidence suggests that radiation dose and dose*elapsed time following radiotherapy might be linked to the severity of postradiation lesions. Furthermore, factors such as xerostomia, oral hygiene, and the use of topical fluoride might also play a role in lesion severity.
Supported in part by NIH/NIDCR K23 DE01623.