INCISOR TOOTH BREAKAGE, ENAMEL DEFECTS, AND PERIODONTITIS IN A DECLINING ALASKAN MOOSE POPULATION

Abstract

We examined 56 anterior segments of mandibles from moose harvested from a declining population that was affected by tooth wear and breakage at higher rates than in moose elsewhere on the Seward Peninsula, Alaska. Incisor teeth were examined for extent of tooth wear and breakage, the degree and prevalence of surface enamel defects, and radiographic evidence of periodontitis. Body size (incisor arcade width of adult moose) and body condition index (timing of tooth eruption in yearlings) of the Seward Peninsula population were compared to other Alaskan moose populations. Mean (± SE) age of adult moose in the study was 4.6 ± 0.4 years. The age distribution of harvested moose was 32% yearling, 61% young adult (2-6 years old), 4% prime adult (7-11 years old), and 4% old moose (> 11 years old). Comparatively smaller body size in moose observed in this study probably reflects the absence of older animals in the 2002 harvest. Timing of tooth eruption in yearlings was within the range of other moose populations. Mean tooth wear and breakage score was 2.1 ± 0.2. Ninety-three percent of the teeth exhibited hypoplastic enamel defects (pits) and staining, while 59% exhibited vertical and horizontal fracture lines on both labial and lingual tooth surfaces. Fifty-three percent of examined
teeth showed radiographic signs consistent with periodontitis. Evidence of osteoporosis was present in 74% of the examined jaws. We hypothesize that observed enamel defects exacerbate age-related tooth wear and breakage in this population thereby resulting in accelerated demise of older animals. The skewed age distribution, with very few animals > 7 years supports this conclusion. The etiology of the observed enamel defects is unclear and requires further investigation.