Comparative analysis of dental fluorosis in roe deer (Capreolus capreolus)and red deer (Cervus elaphus): interdental variation and species differences

The interdental and interspecific variation in the prevalence and severity of macroscopic fluorotic alterations of the permanent mandibular cheek teet h (P2-4, M1-3) was studied in 331 roe deer and 62 red deer exhibiting sever e dental fluorosis. The material originated from the fluoride-polluted regi on of the Ore mountains and their southern foreland (Czech-German border re gion). Scoring of dental fluorosis was based on an ordinal measurement scal e with six scores (score 0: unfluorosed, scores 1-5. increasing severity of fluorotic alterations). The observed variation in dental fluorosis both wi thin the cheek tooth row of a species and between certain homologous teeth of roe and red deer could be related to the development of the dentition in the two species, especially the timing of tooth crown formation in relatio n to weaning and the subsequent period, where the animals feed upon (fluori de-contaminated) plant material. The lower prevalence (roe deer: 3%, red de er: 42%) and severity (fluorosis scores less than or equal to 2) of dental fluorosis in the M-1 compared to the other permanent cheek teeth were attri buted to the fact that the crown formation of this tooth takes place largel y (roe deer) or to a considerable extent (red deer) prenatally and during t he period of milk feeding. It is assumed that during these ontogenetic stag es several mechanisms (partial placental diffusion barrier to fluoride, low fluoride content of milk, rapid clearance of fluoride from the blood resul ting from a high skeletal growth rate) to some extent protect the developin g teeth from increased fluoride exposure. Therefore, in both species appare ntly only the (late) maturation stage of M-1 amelogenesis can be affected b y fluoride in a way to induce visible enamel changes. The higher prevalence and severity of fluorotic lesions in the M-2 of red than roe deer was rela ted to the fact that in the former species crown formation of this tooth, l ike in the P2-4 and M-3 of both species, takes place completely post-weanin g.