History and Physical Examination Findings

A 4-year-old 3.6-kg (7.9-lb) spayed female Miniature Pinscher was evaluated via oral and physical examinations. The dog had a history of being a voracious chewer. No dental care was provided at home, and the diet consisted of dry kibble.

Results of a general physical examination, including thoracic auscultation and abdominal palpation, were unremarkable. The dog's body condition score was 5 on a scale from 1 to 9. Oral examination revealed normal occlusion, mild to moderate calculus, and moderate gingivitis. Results of a CBC and serum biochemical profile were within reference limits, and the dog was anesthetized to allow a complete oral examination.

During oral examination while the dog was anesthetized, the maxillary left and right first premolars, maxillary left second premolar, and mandibular left and right third molars were found to be missing. Several of the remaining molars had excess mobility (> 1 mm of movement in any direction). There was exposure of the furcations of the maxillary right second and fourth premolars, the maxillary left first molar, and the mandibular right fourth premolar. There was attachment loss with root exposure involving multiple incisors and the buccal aspect of the maxillary left and right fourth premolars. There was root exposure and a probing depth of 6 mm on the mesial root of the mandibular right second molar and a probing depth of 8 mm on the distobuccal aspect of the mandibular right first molar. Intraoral radiographs were obtained while the dog was anesthetized (Figure 1).

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Intraoral parallel radiographic view of the mandibular right second and first molars and fourth premolar (from left to right) in a dog.

Citation: Journal of the American Veterinary Medical Association 228, 11; 10.2460/javma.228.11.1683

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Diagnostic Imaging Findings and Interpretation

There is severe periodontitis (> 50% bone loss) involving the entire mesial root of the mandibular right second molar and distal root of the mandibular right first molar, exposure of the furcation of the mandibular right second molar, and moderate periodontitis (25% to 50% bone loss) affecting the mesial aspect of the mesial root of the mandibular right first molar and distal root of the mandibular right fourth premolar (Figure 2). In addition, there is combined horizontal and vertical bone loss at the furcations of the fourth premolar and second molar and at the distal and mesial alveolar margins of the first molar.

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Same radiographic view as in Figure 1. Notice the extensive vertical (black arrows) and horizontal (white arrows) bone loss.

Citation: Journal of the American Veterinary Medical Association 228, 11; 10.2460/javma.228.11.1683

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Radiographic findings in conjunction with the excessive probing depths were considered indicative of an infrabony defect approaching a cup on the distal root of the mandibular right first molar and a 2-wall infrabony defect between the mandibular right first molar and fourth premolar. Periodontal disease involving the fourth premolar was described as moderate to severe, even though there was < 50% alveolar bone loss, on the basis of exposure of the furcation. A diagnosis of focal advanced periodontal disease with horizontal and vertical bone loss patterns was made.

Treatment and Outcome

The treatment plan included supra- and subgingival scaling and polishing, root planing, extraction of severely affected teeth, and periodontal surgery. Several molars, including the mandibular right second molar, were extracted on the basis of excessive mobility and severe periodontal disease. Root planing was performed by use of a closed technique on the distal root of the mandibular right first molar. All extraction sites were closed with absorbable suture. Amoxicillin-clavulanate (46.8 mg, PO, q 12 h) and carprofen (12.5 mg, PO, q 12 h) were dispensed, and additional periodontal treatment was scheduled.

Five weeks after the initial treatment, the extraction sites had healed. The probing depth was 6 mm on the distal aspect of the mandibular right first molar, 4 mm on the distobuccal aspect, 4 mm on the mesiobuccal aspect, and 5 mm on the mesiolingual aspect. The dog was anesthetized, and a right inferior alveolar nerve block was administered with bupivacaine. A full-thickness gingival flap with vertical releasing incisions was elevated distal to the mandibular right first molar and extending to the mesial line angle of the fourth premolar. The premolar was sectioned at the furcation and extracted in 2 fragments. Alveoloplasty was performed to remove sharp edges from the alveolar margin, and open root planing was performed on the distal and mesial root surfaces of the first molar with a periodontal curette. An osteoconductive bioactive glass particulate graft was applied in the distal and mesial infrabony pockets and alveolus of the fourth premolar. The gingival flap was closed with 5-0 absorbable suture.

The dog was reexamined 6 weeks after the second periodontal surgery. The gingival flap incision had healed, and the sutures had resorbed. There was a 3-mm probing depth on the mesiolingual aspect of the mandibular right first molar with subgingival calculus. Examination of an intraoral radiograph revealed radiographic healing of all infrabony defects.

Daily home dental hygiene and routine (ie, 2 to 3 times/y) periodontal treatment were planned to prevent further bone and tooth loss associated with progression of periodontal disease.

Comments

Advanced periodontal disease was not evident in this patient during the initial oral examination and unexpected in a dog of this age. However, in a study¹ involving 1,350 dogs, there was an association between body weight and severity of periodontal disease, with a rapid decrease in disease severity from very small dogs (< 8 kg [18 lb]) to medium-sized dogs (8 to 60 kg [18 to 132 lb]). Probing of the sulci and intraoral radiography revealed the extent of the disease in this dog.

Horizontal bone loss occurs when alveolar marginal bone resorption occurs parallel to the cementoenamel junction. Vertical (infrabony) bone loss occurs when resorption occurs in an apical direction along a specific root surface.² The goals of periodontal treatment include reduction of the infrabony defect and elimination of soft tissue and bony lesions, removal or arrest of the periodontal lesion with correction or cure of the deformity created by it, and alteration of conditions within the mouth that are conducive or contributory to the establishment of periodontal disease.³

In dogs, the canine and carnassial teeth are considered strategic. If moderate periodontal disease develops on a nonstrategic tooth adjacent to a strategic tooth such that viability of the strategic tooth is endangered, extraction of the nonstrategic tooth may be the best treatment option.⁴ In the dog described in the present report, the mandibular right fourth premolar was extracted as part of the treatment plan to save the mandibular right first molar.