VETERINARSKI ARHIV 68 (2), 63-70, 1998

ISSN 0372-5480
Printed in Croatia





Mandibulectomy as a method of treatment of a mandibular canine tooth retention and
secondary fibrous epulis in a dog

Ivan Borissov1*, Michail Pascalev1, Ivan Dinev2, and Ivan Valchev2

1Department of Surgery and Radiology, Faculty of Veterinary Medicine,
University of Thrace, Stara Zagora, Bulgaria

2Department of Pathologic Anatomy, Faculty of Veterinary Medicine,
University of Thrace, Stara Zagora, Bulgaria





* Contact address:
Prof. Dr. Ivan Borissov,
Department of Surgery and Radiology, Faculty of Veterinary Medicine, University of Thrace, 6000 Stara Zagora, Bulgaria,
Phone: 359 42 280 128 97; Fax: 359 42 395 46


BORISSOV, I., M. PASCALEV, I. DINEV, I. VALCHEV: Mandibulectomy as a method of treatment of a mandibular canine tooth retention and secondary fibrous epulis in a dog. Vet. arhiv 68, 63-70, 1998.

ABSTRACT

A clinical case of mandibular canine tooth retention and secondary fibrous epulis in a dog was described. Clinical, paraclinical and radiological studies, as well as rostral mandibulectomy, were performed. The histological study of gingival and bone tissue cross-sections of the affected mandibular part revealed dystrophic, necrotic, inflammatory and reparatory-compensatory changes, characteristic of that type of lesion. The performance of mandibulectomy was found to be justified in cases of permanent and irreversible changes in both solid and soft peridental tissues, accompanied by destructive changes in the mandible in young and valuable animals.

Key words: epulis, dog, mandibulectomy, tooth retention



Introduction

The incidence of oral malformations of dental origin in dogs is increasing, as is the interest in veterinary dentistry.

According to HOYT and WITHROW (1984) and PATNAIK et al. (1975) those tumours represent about 5.4% of all canine tumours. JUBB et al. (1985) reported that the oral and pharyngeal mucoses are in fourth place in the localisation of neoplastic and neoplastic-like growths in the dog.

One of the commonest lesions in canine oral pathology is the tumour, known as epulis. According to GARDNER (1982) the use of this term in veterinary medicine has been inconsistent. Later, studying oral pathology in the dog, he divided the canine epulides into two main classes: reactive lesions and peripheral odontogenic tumours (GARDNER, 1996). The fibrous epulis in the dog was similar to the human reactive fibroma. Recent data has determined the lesion as an inflammatory fibrous hyperplasia (REICHART et al., 1992) or as a focal fibrous hyperplasia (VERSTRAETE et al., 1992). Etiologically, these kinds of tumour are related to the presence of a large amount of subgingival dental tartar in older animals. Compressing the gingiva, it provoked hyperaemia, hypertrophy and thus - epulides. When the appearance of an epulis coincided with the period of replacement of deciduous teeth by permanent ones, the involvement of the retention, or disposition, of a permanent tooth was strongly suspected.

The aim of the present report was to describe a rare case of fibrous hyperplasia in a dog, caused by a retention of a mandibular canine tooth.

Materials and methods

The observations, clinical, paraclinical, radiological and pathohistological studies were performed on a male 8-month-old Drathaar dog, referred to the Surgical Clinic of the Faculty of Veterinary Medicine, Stara Zagora, Bulgaria.

The radiological study was realised with a stationary unit TUR-800, using an intraoral ventrodorsal radiological view.

Clinical and paraclinical observations were carried out in accordance with routine methods.

Following confirmation of the presence of all clinical and radiological indications, a rostral unilateral mandibulectomy was performed according to the method described by BOJRAB et al. (1990).

Samples from the soft and solid tissues of the resected mandibular part were taken for histological study. After fixation in 10% neutral formalin and demineralisation of the bone tissue in HNO3, the materials were embedded in paraffin and the cross-sections stained with hematoxillin-eosin (H&E).

Results

The history of the disease revealed that two months previously, when the dog was six months old, a protuberance appeared in the left mandibular region, close to the site of localisation of the mandibular canine tooth. The size of the protuberance increased very rapidly, reaching the size of an apple in less than two months and occupying the whole space caudal to the third incisor up to the first premolar (Fig. 1). The consistency of the formation was hard, and in the central part a fistula with a spare exudation was found.

Fig. 1.

Fig. 1. Macroscopic view of growth before the operation


Paraclinical studies showed no abnormalities (Hb - 140 g/l; Hc - 0.43 l/l; Er - 6.75 T/l; Leuc - 10.8 G/l; total protein 58 g/l; blood sugar 4.2 mmol/l) except for elevated values of plasma sialic acid (325 E).

Radiography showed a retention of the permanent left mandibular canine tooth (Fig. 2).

Fig. 2.

Fig. 2. Radiograph of the retention canine tooth


Because of its retention and disposition, the permanent tooth could not achieve its natural position, causing hyperplasia of both solid and soft tissue in the area. The chronicity of the case, the irreversible changes, as well as a lack of alternative methods of treatment, justified the performance of rostral mandibulectomy.

The operation was performed routinely (BOJRAB et al., 1990). The abnormal mandibular part was excised to the mandibular symphysis rostrally and to the space between the second and third premolar caudally. The cheek and both lips were subjected to skin plastics. The postoperative period was without complications and the patient was discharged after 10 days (Fig. 3).

Fig. 3.

Fig. 3. Exterior of the patient after the mandibulectomy and skin plastics


After the mandibulectomy, via removal of medial bone tissue, a hyperplasia of the canine tooth rostrally was observed. The hyperplasia involved both the gingiva and the alveolar bone component (Figs. 4 and 5). The compact bone structure of the mandible had become cancellous, and the gingiva was hyperplastic and firm. The disposition of the tooth resulted in the formation of a sinus, filled with seropurulent exudate that opened on the lateral side.

Fig. 4.

Fig. 4. Gingival hyperplasia of affected region


Fig. 5.

Fig. 5. Position of the retention canine tooth in bone tissue after the mandibulectomy


The histological study showed hyperplasia of a well-vascularised, compact fibrous tissue covered with a multilayered squamous epithelium. Within, foci with necrosis, ulcerations and neutrophil-leucocytic infiltration were observed.

The histological samples of demineralized bone tissue of the affected mandible showed osteolytic change, with formation of lacunae (Fig. 6) and hyperplastic changes, following a compensatory-reparatory reaction manifested through fibrous osteodystrophy (Fig. 7). Separate osteoclasts from the primary bone tissue were found in several areas. (Fig. 8).

Fig. 6.

Fig. 6. Formation of bone lacunae in the lysed bone tissue.
H&E; scale bar = 350 Ám.


Fig. 7.

Fig. 7. Fibrous osteodystrophy. H&E; scale bar = 350 Ám.


Fig. 8.

Fig. 8. Residual osteoclasts within the fibrous tissue. H&E; scale bar = 350 Ám.


Discussion

The appearance of the described growth coincided with the period of replacement of deciduous teeth by permanent teeth. We therefore concluded that the cause was the retention and the disposition of the permanent canine tooth, which was confirmed by radiology. The trauma, resulting from the compression of both solid and soft tissues, was probably the cause of hyperplasia.

The histology proved the reactive character of the lesion. Our results are similar to those of LANGHAM et al. (1965), who reported that oral fibrous hyperplasia was a reactive and not a neoplastic process.

The reactive character of those hyperplastic aseptic inflammatory lesions was confirmed by the clinical status of the patient, monitored for six months after the operation. The latter resulted in no difficulties when feeding and drinking. The exterior appearance was also good.

Conclusions

1. The retention of permanent teeth is a prerequisite for the development of the reactive hyperplastic processes of both solid and soft peridental tissues.

2. Pathohistologically, that lesion could be classified as reactive epulis, similar to the human classification.

3. The performance of mandibulectomy is justified in cases of permanent and irreversible changes in the mandible in young and valuable animals.

References

BOJRAB, M. J., M. A. TOLEN (1990): Surgical Management of Oral Neoplasia. In: Small Animal Oral Medicine and Surgery. Lea and Febiger. Philadelphia. pp. 110-112.

GARDNER, D. G. (1982): The peripheral odontogenic fibroma - an attempt at classification, Oral. Surg., Oral Med., Oral Pathol. 54, 8.

GARDNER, D. G. (1996): Epulides in the dog: a review. J. Oral Pathol. Med. 25, 7.

HOYT, R. F., WITHROW, S. J. (1984): Oral malignancy in the dog. J. Anim. Hosp. Assoc. 20, 83.

JUBB, K. F., P. C. KENNEDY, N. PALMER (1985): The alimentary system. In: Pathology of Domestic Animals, 3rd ed., vol. 2. Academic Press. Orlando, Florida. pp. 17-22.

LANGHAM, R. F., K. K. KEAHEY, U. V. MOSTOSKY, R. G. SCHIRMER (1965): Oral adamantinomas in the dog. J. Am. Vet. Med. Assoc. 146, 474-480.

PATNAIK A. V., A. I. HURVITZ, G. R. F. JOHNSON (1975): Nonhematopoetic neoplasms in cats. J. Nat. Cancer Inst. 54, 855-859.

REICHART, P. A., H. P. PHILIPSEN, U. M. DURR (1992): Epulides in dogs, J. Comp. Pathol. 106, 82-86.

VERSTRAETE, F. J. M., A. J. LIGHELM, A. WEBER (1992): The histological nature of epulides in dogs. J. Comp. Pathol. 106, 169-182.

Received: 25 August 1997
Accepted: 11 March 1998



BORISSOV, I., M. PASCALEV, I. DINEV, I. VALCHEV: Mandibulektomija kao nacin lijecenja retencije donjeg ocnjaka i sekundarnog fibroznog epulisa u psa. Vet. arhiv 68, 63-70, 1998.

SAZETAK

Opisan je klinicki slucaj retencije donjeg ocnjaka i sekundarni fibrozni epulis u psa. Obavljena su klinicka, paraklinicka i radioloska istrazivanja, kao i rostralna mandibulektomija. Histoloskom pretragom rezova gingive i kostanog tkiva zahvacenog mandibularnog podrucja otkrivene su distroficne, nekroticne, upalne i reparatorno-kompenzatorne promjene, osebujne za ovaj tip lezija. Mandibulektomija je opravdana u slucajevima permanentnih i ireverzibilnih promjena na tvrdom i mekom peridentalnom tkivu, pracenima destruktivnim promjenama donje celjusti u mladih i vrijednih zivotinja.

Kljucne rijeci: epulis, pas, mandibulektomija, retencija zuba


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