Teaching Case

Buccal routine examination

A 34 year-old man, presented for buccal routine examination. Medical history was negative. Panthography was performed and revealed focal irregular areas of over density, obliterating details of some teeth roots. These imaging abnormalities where seen at the level of 33, 34 and 41 to 43 (Fig. 1). A HR-CT in axial plan, demonstrated their location on the lingual aspect of the mandible (Fig.2). Torus mandibularis was diagnosed.

Torus mandibularis (TM) is a nodular bony protuberance located on the lingual aspect of the mandible. This anatomic peculiarity is known since 1814. Its geographic repartition is described in the literature. The incidence varies between 0.5 to 85% and the highest prevalence is found in habitants of northern countries. For most of authors, TM is commonly observed in young adults and middle-age men and generally, does not cause any discomfort. The lesion is suspected on panthography since it is the first examination in a dental chek-up. Then the diagnosis is confirmed by occlusal mandibular radiography or computed tomography. On these imaging modalities, it appears as nodular swellings from the alveolar bone, that may be located between the lateral incisor and the last molar tooth. The histological feature of TM is described as lamellar periostal hyperplasia with a spongy layer if it becommes very large. The aetiology is still unclear. According to recent literature, TM is caused by an interplay of genetic, environmental factors and masticatory hyperfunction. Principal differential diagnosis is buccal exostosis (BE). BE and TM have the same histological aspect. The difference resides in the location of BE on the buccal aspect of the mandible at premolars and molars areas. Since TM is a benign lesion, the treatment is conservative. Surgical management would be needed for large and very symptomatic cases. The problem of this entity commes from its possible association with osteomyelitis, squamous cell carcinoma and temporomandibular disorders (TMD). In their article, Sirirungrojying et al. conclude that TM might be considered as an indicator of increased risk of TMD (clinical problems of masticatory musculature and temporomandibular joint).