Loss of tooth-supporting bone in the koala (Phascolarctos cinereus) with age

Abstract

This study investigated changes in alveolar bone height in free-ranging koalas of different age groups. Twenty-seven free-ranging Queensland koalas (15 female, 12 male), admitted to the Moggill Koala Hospital, Brisbane, were used in this study. Koalas were divided into three groups (young, adult, old) on the basis of tooth wear, each group containing nine animals. Defleshed jaws were examined for the presence of alveolar bone defects. The distance from the cemento-enamel junction and the interproximal crestal alveolar bone height was measured on the buccal aspects of the second and third molars. Jaws were photographed and radiographed. Bone defects (dehiscences and fenestrations) were observed in both jaws and were predominantly located on the buccal aspect of the alveolar process. The loss of height of crestal alveolar bone, relative to the cemento-enamel junction, increased with age, with 25 koalas showing moderate to severe bone loss and only two koalas having none/mild loss levels at all measurement sites. Female koalas had higher frequency of ‘none/mild’ cases of bone loss than did males. There was no variation in levels of alveolar bone loss between the upper and lower jaws or the corresponding right and left arches.

Oral health in South East Queensland Koalas: Prevalence of periodontal disease and other pathologies

“…Gingivitis and periodontitis was reported in koalas (Bird, 2002) some with severe loss of alveolar bone associated with age and conditions such as food impaction and tooth movement (Lee et al, 2011). The areas found most susceptible to interproximal alveolar bone loss were those adjacent to the second and third molars (Figure 2-13), in both the maxilla and mandible.…”

“…In dogs and cats when controlling for age the oral health index still increased in one study (Gawor et al, 2006). In the koala advanced tooth wear occurs in older animals, natural abrasion and attrition reduces the stability of the teeth which increases the risk of having bone loss (Lee et al, 2011). Sexual dimorphism occurs in many aspects of dentistry.…”

“…The areas found most susceptible to interproximal alveolar bone loss were those adjacent to the second and third molars (Figure 2-13), in both the maxilla and mandible. Displaced teeth, prior oral injuries, tongue abnormalities, gingival hyperplasia, tooth mobility, black stain, dehiscences, and fenestrations were also present (Lee et al, 2011).…”

“…Department employees provide veterinarian assessment and treatment, vegetation collection and facility maintenance (McKinnon, 2002). Trialling new veterinarian therapies, public relations and collaborations with researchers and similar Australian facilities are also ongoing functions of the staff (McKinnon, 2002, Lee et al, 2011, Pettett et al, 2012. Animals brought to the facility are diagnosed, treated and maintained after sustaining injury, disease or orphan status.…”

Marsupial oral cavity microbiome

“…There have been many studies determining which of the causative agent(s) initiate oral diseases in humans and domesticated animals. Marsupials also have oral diseases 3,4 and culture-dependent studies have shown a range of bacteria can be isolated from the marsupial oral cavity 5 . However culture-based studies, while useful to enable precise characterisation of putative periodontopathogens, generally underestimate microbial community diversity.…”