Dental paediatric imaging - an investigation into low dose radiation-induced risks

Liese Gilles, Niels Belmans, Marjan Moreels

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    During the last decade dental cone beam CT (CBCT) has become a popular diagnostic tool in paediatric dentistry. Although dental CBCT is considered a low dose imaging modality, it remains uncertain whether low dose radiation exposure causes adverse health effects. This is especially important regarding children as they are more sensitive to ionizing radiation than adults. Therefore, we hypothesize that low-dose radiation exposure, as used in dental CBCT, induces DNA damage and oxidative stress, in dental stem cells (in-vitro) and in buccal cells and saliva (ex-vivo) in an age-dependent manner. Dental pulp stem cells, stem cells of the apical papilla and dental follicle stem cells were isolated from children and irradiated in vitro with low dose (0, 5, 10, 20, 50, 100 mGy) ionizing radiation. After X-ray exposure, oxidative stress and the induction and repair kinetics of DNA double strand breaks (DSBs) were analysed at multiple time points. Furthermore, exfoliated oral mucosa cells and saliva were collected, from children and adults, to compare the frequency of DNA DSBs and the level of oxidative stress before and after dental CBCT exposure. We observed that the frequency of DNA DSBs increased with the dose (0 - 100 mGy) with a peak response 0.5 - 1 hour post irradiation (p.i.), after which the number of DNA DSBs continuously decreased returning to basal levels 24 hours p.i.. Our ex vivo data revealed that in both children and adults, dental CBCT exposure did not significantly increase the number of DNA DSBs 30 minutes and 24 hours after exposure. Finally, only in children, a significant increase in salivary 8-OHdG concentration was observed after dental CBCT exposure. In summary, our results support the linear non-threshold dose-response-relationship as observed in dental stem cells exposed to low dose X-irradiation (in vitro). Furthermore, it appears that dental CBCT does not induce more DNA DSBs in children and adults, but induces more oxidative DNA damage (8-OHdG) in children. The results of this study contribute to a better understanding of the potential biological effects of dental CBCT in children.
    Original languageEnglish
    Awarding Institution
    • Uhasselt - Hasselt University
    • Belmans, Niels, Supervisor
    • Moreels, Marjan, Supervisor
    • Lambrichts, Ivo, Supervisor, External person
    Date of Award6 Jun 2017
    StatePublished - 21 Jun 2017

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