November 2010
Dr Gerhard Steenkamp

A squirrel monkey of unknown age is presented. The monkey is slightly anorexic. According to the owner, the monkey fell from a branch and now has bleeding on the chin.


On clinical examination slight calculus is present on the teeth. Both central mandibular incisors are absent. On the ventral chin a hard lump is found in association with the open wound.

What would your next diagnostic step be?
Firstly, take a radiograph of the affected area. Intra-oral dental film/digital radiographs are ideal as the film are non-screen film and supply superior detail. They are also small enough to give very good detail of the mandible and teeth.

Here is the digital intraoral radiograph of the patient. (R)

What radiological pathology can you see on this intraoral ventro-dorsal view?
Similar to humans, primates have 2 incisors in each quadrant, one less than carnivores. The root remnants of both central incisors are present.

There is a large area of bone loss associated with the apices of the left mandibular canine tooth (33) and premolar (34). On intra-oral examination, tooth (33) was discoloured compared to tooth 34 and pulp exposure could also be detected on tooth 33 using a shepherd’s hook explorer. Tooth discolouration is a sign of loss of vitality of the tooth. The pulp infection/inflammation spread through the apex to the adjacent periapical bone which resulted in the recruitment of bone resorbing osteoclasts. Pulpitis/pulp necrosis may give rise to periapical granuloma/cyst/abscesses, all of which will give a similar radiological image and can only be diagnosed on histological examination.

Tooth 34 will be followed up.

What is your final diagnosis?

Presence of root remnants of teeth 31 and 41Pulpitis of non-vital tooth 33 with fistula formation associated with it.

How would you manage this patient?

Extraction of the root rests of teeth 31 and 41 as well as the non-vital canine tooth 33.Follow-up of tooth 34 in order to make sure that it has not been affected by the periapical infection.

Root canal treatment on tooth 33 would have been challenging. There is a good chance that conventional endodontic treatment would fail, especially if the periapical area represented a radicular cyst and a surgical endodontic procedure to remove the periapical tissue on such a small tooth would be extremely difficult.

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