Caudal mucogingival lesions secondary to traumatic dental occlusion in 27 cats: macroscopic and microscopic description, treatment and follow-up

Abstract

The main aim of this retrospective study was to describe clinical and histopathological findings in cats with mucogingival lesions developed at the contact point of the premolar and molar teeth of the opposite quadrant. Cases were retrieved following manual review of the medical records, dental records and photographic documentation of all feline dental patients visited in the period between February 2001 and August 2011. Cats showing different lesions at different times were calculated as multiple cases. A total of 27 cats (31 cases) with 44 lesions (26 proliferations [59%], 11 clefts [25%] and seven foveae [16%]) were included. Mean age at the time of the first visit was 6.6 years. The lesion object of the study was the main reason for presentation in only five cases (16%). Proliferations showed two different histopathological patterns and had characteristics in common with human oral pyogenic granuloma. Successful treatment was achieved in all cases by removing the occlusal contact by dental extraction or coronal reduction, possibly associated with lesion excision. This study underlines the need for a thorough oral examination and evaluation of dental occlusion in all patients. Causes for the development of traumatic occlusion may include an acquired overbite (possibly secondary to selective dental extraction), congenital or post-traumatic malocclusion, abnormal latero-lateral mobility of the mandible, occlusal drift of the premolar and molar teeth, and/or alveolar bone expansion.

Figure 1

Left mandibular proliferative lesion (arrow) in contact with the mesiobuccal cusp of the maxillary fourth premolar tooth (asterisk) (case C). (a) Closed mouth; (b) open mouth

Figure 2

Foveae (arrows) on the gingiva of the mesial root of the right mandibular first molar and fourth premolar teeth in contact with the mesiobuccal cusp of the maxillary fourth premolar (red asterisk) and the middle cusp of the maxillary third premolar tooth (blue asterisk), respectively (case Alfa 1–2)

Figure 3

Buccal gingival cleft (arrow) at the mesial root of the right mandibular first molar tooth, in contact with the mesiobuccal cusp of the maxillary fourth premolar tooth (asterisk). Ten-year-old, female spayed, domestic shorthair cat (case not included in the current series)

Figure 4

Reduction of the mesial cusp of the maxillary fourth premolar tooth in contact with a gingival cleft developed on the buccal side of the right mandibular first molar tooth (case not included in the current series). (a) Preoperative image. (b) After dental scaling, polishing and radiographical examination, the portion of crown to be removed is marked with a pen. (c) Postoperative image. The exposed dentine may be protected with a layer of unfilled resin

Figure 5

Histological examination of a slightly elevated plaque-like mucosal lesion showing ulcerations and diffuse, superficial and deep, interstitial infiltrate, consisting of lymphocytes and plasma cells (type 1 histological pattern; case M) (haematoxylin and eosin stain; bar = 200 μm, x 4). Inset: magnified area (x 40)

Figure 6

Histological examination of an exophytic mucosal lesion characterised by massive fibrovascular hyperplasia (type 2 histological pattern; case A4) (haematoxylin and eosin stain; bar = 500 μm, x 4). Inset: magnified area showing granulation type tissue (x 40)

Figure 7

Histological examination of a proliferative mucosal lesion (case G). (a) Areas of hypercellular compact fibrous tissue with scant inflammation. (b) Hyperplastic fibrous tissue, low cellularity and abundant myxoid matrix. A mitotic figure is evident (arrow). Haematoxylin and eosin stain (bar = 40 μm, x 40)