A study of oral and dental diseases in a population of European polecats (Mustela putorius)

Foto: Maja Čonč

Z dovoljenjem avtorjev objavljamo študijo o ustnih in dentalnih boleznih v populaciji evropskih dihurjev (M. putorius). Prispevek je bil predstavljen na IX. mednarodnem simpoziju  o prostoživečih živalskih vrstah v Košicah (Slovaška).
Avtorji so v študiji pregledali enaintrideset lobanj evropskih dihurjev iz muzejske zbirke Prirodoslovnega muzeja Slovenije. Lobanje so bile pregledane z vizualnim pregledom in zobozdravstveno radiografijo. Med pregledanimi dihurji je bilo 8 samcev, 4 samice, spol ostalih osebkov je neznan. Starost živali ni znana, na osnovi  širine zobne pulpe na radiografskih posnetkih, avtorji ugotavljajo, da je bila večina živali mlada (23 živali; 74,2 %).


Polecats (Mustela putorius) are widespread through most of Europe. However, data on oral and dental diseases of free-living European polecats are rather rare or lacking.


Thirty-one polecat skulls from a museum collection were examined by means of visual inspection and dental radiography. Specimens included 8 males and 4 females, sex of the rest was unknown. Age of animals was unknown, but based on radiographic width of the dental pulp (Figs. 1a-c), majority (23 animals; 74,2%) were young.

Fig. 1: Dental radiograph of the right maxillary canine tooth of 3 different specimens. Note the differences in the width of the pulp. In a juvenile animal, the pulp cavity is extremely large and the apex of the erupting permanent canine tooth is open, while deciduous canine tooth has not yet exfoliated (a). Fully formed permanent canine tooth in a young animal has large pulp cavity, but the apex has formed (b). With aging, secondary dentin is laid down by odontoblasts in the pulp and pulp cavity narrows (c).


Presence of teeth
Of potentially maximum 1054 teeth, 788 teeth (74,8%) were evaluated. Of the missing teeth, 248 (93,2%) were missing artefactually, 6 teeth (2,3%) were mising presumably acquired and 12 (4,5%) presumably congenital.

Occlusion and tooth form
Linguoversion of mandibular second incisor teeth was noted in 20 of  21 (95,2%) specimens (Fig. 2). Crowding of teeth was noted in 2 specimens. Apart one tooth with odontodysplasia, all teeth were normal in morphology. All incisor and canine teeth, as well as all maxillary second premolar teeth and mandibular third molar teeth were single-rooted. Mandibular second premolar teeth were mostly (97,1%) single-rooted. Maxillary third premolar teeth were mostly (98,4%) two-rooted. Mandibular third premolar teeth were either single-rooted (13,2%) or two-rooted (86,8%); of the latest 42,2% had either fused or convergent roots (Fig. 3). Mandibular fourth premolar teeth were all two-rooted with 19,0% having convergent roots. All maxillary fourth premolar teeth and first molar teeth as well as mandibular first molar teeth were three-rooted (Fig. 3).

Attrition/abrasion affected 16 (51,6%) animals and 85 (10,8%) teeth. Mandibular and maxillary teeth were almost equally affected (10,3%% vs. 9,8% of teeth evaluated, respectively). In the maxilla, incisor and canine teeth were much more commonly affected than premolar and molar teeth (17,7% vs. 2,2% of teeth evaluated, respectively) (Fig. 4).

Tooth fractures and periapical disease
Dental fractures affected 17 (54,8%) animals and 50 (6,3%) teeth. Maxillary teeth were more often affected than mandibular teeth (7,6% vs. 4,7%, respectively), and canine teeth were most commonly affected teeth (46,0% of fractures). Complicated tooth fractures were common (82,0% of all fracture types) (Fig. 5). Signs of endodontic disease were observed in 22,0% of the fractured teeth with exposed pulp. Radiographic signs included periapical radiolucency (Figs. 3, 6, 7) and failure of pulp cavity to narrow (Fig. 7). In one case (Figs. 5, 6) fenestration was noted above the root with localized bony changes, suggestive of an abscess and localized osteomyelitis.

Apart from the juvenile animal with mixed dentition, all animals showed signs of periodontitis. Majority of teeth were affected by mild-moderate periodontitis (stage 2 and 3) with only 3 showing severe horizontal and vertical bone loss (stage 4; Fig. 8). Maxillary teeth were more often affected (50,6% of the teeth) than mandibular teeth (25,1% of the teeth).

Other findings
In 24,6% maxillary first molars were found to have palatal root penetrating into the orbit. 34,7% of canine teeth were showing signs of axial extrusion. 17 specimens (54,8%) showed cranial lesions consistent with helminth parasites infestation.

Fig. 2: Rostral mandibles, occlusal view. Linguoversion of mandibular second incisor teeth. Note also mild abrasion of all incisor teeth and complicated fracture of both mandibular canine teeth.
Fig. 3: Dental radiograph of the right mandible. Canine tooth has complicated crown fracture and periapical radiolucency indicating periradicular infection. Second premolar tooth is missing. Third premolar tooth has convergent roots. First molar tooth is three-rooted with a slender middle root.


Fig. 4: Right maxilla, lingual view. Canine tooth has severe attrition/abrasion with exposure of dentin and pulp cavity with tertiray dentin formation. Second and third premolar teeth have only mild attrition/abrasion with minor exposure of dentin on the cuspal tip, more pronounced on the fourth premolar tooth.
Fig. 5: Right maxilla, buccal view. Second premolar tooth is missing. Fourth premolar tooth has complicated crown-root fracture. There is a fenestration at the apex of the distal root of this tooth and bony changes involving caudal maxilla and rostral part of the zygomatic arch. Note also moderate horizontal bone loss at third and fourth premolar teeth.


Fig. 6: Dental radiograph of the premolar and molar teeth from Fig. 5. Note periapical radiolucency at the distal root of the fractured fourth premolar tooth. Bone of the caudal maxilla and rostral part of the zygomatic arch has radiographically moth-eaten appearance, suggestive of osteomyelitis.
Fig. 7: Dental radiograph of the rostral maxillae. Note that the right maxillary canine tooth has shorter cusp (is fractured) and pulp cavity is wider comparing to the left canine tooth, indicating a non-vital right maxillary canine tooth (there are no vital odontoblasts to lay down secondary dentin). There is also a periapical radiolucency.
Fig. 8: Left mandible, buccal view. Second premolar tooth is missing. Note mild-moderate horizontal bone loss at the canine tooth and third and fourth premolar teeth, combined with a moderate-severe vertical bone loss at the mesial root of first mandibular molar tooth, suggestive of advanced periodontal disease. There is also moderate attrition/abrasion of the distal aspect of the canine tooth and mild of the cuspal tips of the two premolar teeth.



Variations in dental occlusion and number of roots were noted in comparison to published literature. Attrition/abrasion and dental fractures, especially of canine teeth, were commonly observed. Despite the high occurrence of complicated tooth fractures, periapical disease associated with dental fractures was rare. Periodontal disease was very common, although the animals were considered young.


The authors would like to thank to Slovenian museum of natural history  and Prof. dr. Boris Kryštufek and Mojca Jernejc Kodrič.

Authors: Ana Nemec1, dr. vet. med. PhD DAVDC DEVDC, Marko Zadravec2, dr. vet. med. PhD, Joško Račnik2, dr. vet. med. PhD DECZM (WPH)

Prispevek je v izvirniku objavljen v Book of abstracts IX international symposium on wild fauna, Košice (Slovakia), September 15 – 19, 2015, str. 107.