Bone Exostosis
Jump to navigation
Jump to search
- Nodular swellings of normal bone in the oral cavity
- Also known as tori (torus = singular)
- Common sites:
- Hard palate (torus palatinus)
- Lingual premolar region of the mandible (torus mandibularis)
- Buccal alveolar bone of maxilla or mandible
Epidemiology[edit | edit source]
- Incidence varies between different races[1]
- More common in Inuit, Native American and Asian populations
- Torus palatinus
- More common than mandibular tori
- Incidence - 9-66%
- ♀ > ♂
- Torus mandibularis
- Incidence - 0.5-63.4%
- ♂ > ♀
Clinical Features[edit | edit source]
- Firm swellings with normal overlying mucosa
- Whilst mucosa is normal it is usually thin and can have a blanched appearance (sometimes can ulcerate)
- Small-sized lesions → <3mm elevation and <10mm diameter
- Medium-sized lesions → 3-5mm elevation and 10-15mm diameter
- Large-sized lesions → >5mm elevation and >15mm diameter
- Usually only affects one site in an individual
- Torus palatinus
- Occurs in the midline of the palate (usually in the mid-third)
- Usually symmetrical but if large can also become an irregular rounded mass
- Torus mandibularis
- Found on the lingual surface of the mandible
- Usually adjacent to premolars and above the mylohyoid attachment
- If very large can interfere with tongue movement
- Common presentations:
- Bilateral solitary > bilateral multiple > unilateral solitary > unilateral multiple
- Other sites
- Multiple bone exposes can also affect the buccal aspect of maxilla or mandible
Aetiology and Pathogenesis[edit | edit source]
Aetiology[edit | edit source]
- Largely unknown
- Some suggestions:
- Hereditary (autosomal dominant inheritance has been described in some)
- Masticatory hyperfunction
Pathogenesis[edit | edit source]
- Also largely unknown
- In palatal tori, there is suggestion of continued activity of the embryonic osteoblasts which pile up at the palatal suture after the median palatal suture junction is completed
Investigations[edit | edit source]
Imaging[edit | edit source]
- Radiographically tori appear as radiopaque masses
- Dense bone ∴ they can obliterate details of the teeth and maxillary sinus in plain film radiographs
- In large tori - the spongy layer in the middle appears less dense than the cortical bone
Histology[edit | edit source]
- Torus palatinus
- Cross-sectional analysis of tori palatine demonstrate three layers:
- Nasal compact layer - same thickness irrespective of size of tori ∴ confirming that development occurs by downward growth (nasal floor always remains flat)
- Middle spongy layer - may not be seen in smaller tori
- Oral compact layer
- Cross-sectional analysis of tori palatine demonstrate three layers:
- Torus mandibularis
- Seen as lamellar periosteal outgrowth of the mandible
Management[edit | edit source]
- No active treatment needed
- Patient reassurance
- Removal is sometimes needed if they interfere with function or to facilitate dental prosthesis
- Tori have been described as a source of autogenous bone graft in implant placement[2][3][4]
Prognosis and Complications[edit | edit source]
- Benign
- Recurrent ulceration can occur due to thin overlying mucosa
- Large lesions can interfere with function and dental prosthesis
Follow-up[edit | edit source]
- None needed
References[edit | edit source]
- ↑ Seah YH. Torus palatinus and torus mandibular is: A review of the literature. Australian dental journal. 1995 Oct;40(5):318-21.
- ↑ Barker D, Walls AW, Meechan JG. Ridge augmentation using mandibular tori. British dental journal. 2001 May;190(9):474-6.
- ↑ Ganz SD. Mandibular tori as a source for onlay bone graft augmentation: a surgical procedure. Pract Periodontics Aesthet Dent. 1997 Nov 1;9(9):973-82.
- ↑ Proussaefs P. Clinical and histologic evaluation of the use of mandibular tori as donor site for mandibular block autografts: report of three cases. International Journal of Periodontics & Restorative Dentistry. 2006 Jan 1;26(1).