Radiographic Assessment of Dental Pathology and Abnormalities in Dolphins

Abstract

This study proposes a simple standardized method for the production of analog X-ray images of dolphin teeth, and to explore its potential use as a complementary technique in the evaluation of dental pathology in small cetaceans. We investigated exposure times that produced the best results, and whether radiographs helped in the diagnosis of macroscopic abnormalities. Teeth of six species of dolphins (Delphinidae: Tursiops truncatus, Steno bredanensis, Sotalia guianensis, Delphinus sp., Stenella coeruleoalba, and Stenella frontalis) were X-rayed in an analog dental X-ray machine operating at 70 kVp and 7 mA. Intraoral size 2 standard films were used, and the focus-film distance was standardised at 35 cm. Those species with smaller teeth (total length 12-20 mm) had the best results when exposed for 0.3 seconds, while species with larger teeth (30-45 mm) had to be exposed for 0.4 seconds for their best result. Three independent examiners analysed all the images taken. The average pairwise percent agreement was 73% (Fleiss' Kappa = 0.229), suggesting fair agreement between examiners. Analog X-ray images produced were useful in complementing the diagnosis of dental pathology and abnormalities in dolphins, in addition to allowing the observation of internal details and lesion depths, which would not be possible with conventional macroscopic methods. The use of analog X-ray imaging is easily applicable to the study of dolphin teeth, with low operating costs and simple logistics compared to other non-destructive analytical approaches such as Micro-CT.