Multiple bony overgrowths in the mouth - report of two cases

Summary

Tori and exostoses are benign bony protuberances that arise from bone surfaces in the oral cavity. The etiology of these growths has been implicated as multifactorial, but no consensus has been reached so far. These painless overgrowths seldom present as a complaint in the dental office unless functional or esthetic complications set in, and there is a fear for cancer. Here we discuss two rare cases where bony overgrowths present in the mouth were extensive and multiple.

Introduction

Tori and exostoses are sessile nodular protuberances of mature bone that arise from the maxilla and mandible. The designation of tori and exostoses depends on their location in the oral cavity; torus palatinus is found along the midline of the palate, while torus mandibularis is found along the lingual aspect of the mandible and is usually bilateral. Buccal exostoses occur along the buccal/facial aspect of the maxilla or mandible, while palatal exostoses develop on the palatal aspect of the maxilla. These benign bony hamartomas are generally asymptomatic and consist of mature cortical and trabecular bone (1, 2). This paper reports two cases showing multiple bony overgrowths in the mouth.

Case report

The first case was a 40-year-old male patient who exhibited multiple bony projections along the buccal surfaces of the maxilla and mandible as an incidental finding (Figure 1). The patient did not have any discomfort from these bony lesions which were present for more than 20 years. They were diagnosed as buccal exostoses.

Figure 1.

Case 1 - Multiple buccal exostoses in the maxilla and mandible.

The second case was a 55-year-old male patient who exhibited a large palatal tori and palatal exostoses bilaterally (Figure 2). The bony overgrowths had been present for the past 15 years. They slowly increased in size causing food lodgement between them which was difficult to clean resulting in oral malodour.

Figure 2.

Case 2 - Concurrent palatal tori and palatal exostoses.

History proved to be non-contributory. Both patients gave no family history of similar bony overgrowths in the mouth or elsewhere in the body. There was no history of parafunctional habits and temporomandibular joint disorders. However, when enquired about their dietary habits, almost every meal their diet included consumption of fish and other seafood in various forms.

Panoramic radiographs for both patients and maxillary occlusal view for Case 2 were taken to rule out underlying bone pathology. The radiographic findings were unremarkable.

Discussion

The etiology of tori is thought to be multifactorial where there is an interaction of genetic and environmental factors. The quasi continuous genetic or threshold theory has been considered as the best explanation for etiology of tori. This theory states that the environmental factors must first reach a threshold level before the genetic factors can express themselves in an individual (1, 3–6). An autosomal-dominant pattern of inheritance was noted by Gorsky et al. (3). Since tori appears during the middle phases of life functional factors like masticatory stress have also been considered to play a major role for its occurrence. Eggen and Natvig (7) proposed that the presence of tori was 30% genetic and 70% environmental in terms of masticatory stress. A correlation between the presence of tori and exostoses in patients with parafunctional habits like clenching and grinding has also been demonstrated. Other causative factors include dietary habits (eating supplements or food rich in calcium) and nutritional disturbances (vitamin deficiencies) (8). Consumption of excessive fish has been related to the presence of tori; it was hypothesized that this may be connected to the nutrients present in salt water fish, probably omega-3 polyunsaturated fatty acids and vitamin D (7, 9). Recently studies have reported a correlation of tori with obstructive sleep apnea and temporomandibular joint dysfunction (10, 11).

Prevalence of tori and exostoses varies greatly depending on the population studied. It is generally higher in mongoloids than in caucasoids. The prevalence rate among the mongoloid race was observed to range from 1.4 to 61.7% (6).

Patients with tori or exostoses rarely complain of unaesthetic appearance, speech difficulties due to limited tongue movement and food lodgement resulting in malodour. Certain patients may fear that the lesion is cancerous. In Case 2, the concurrent large palatal tori and palatal exostoses were in close approximation causing food lodgement and cleaning difficulties. Patients may experience trauma or ulceration when masticating hard and sharp food since the soft tissue covering the bony protuberances is reported to be thinner than the surrounding mucosa (9). In addition, recording oral impressions and seating of dentures are difficult in these patients.

The diagnosis of tori or exostoses is done by simple clinical examination. Radiographs are required in situations where the bony protuberances are extremely large, or multiple, or vary in consistency to rule out underlying bone pathology. Radiographs may show normal bone pattern or a slightly radiodense image with a higher density than that of the surrounding bone (9). Distinction between these bony overgrowths and osteomas (exosteal) is often difficult to determine. Other differential diagnoses include organized subperiosteal hematoma, a mature ossifying fibroma with expansion of the cortical plate, and early osteosarcoma or chondrosarcoma (2). Bone disorders like sclerosteosis, high bone mass trait and fibrous dysplasia should also be excluded.

Patients with multiple bony growths or lesions not in the classic torus or exostoses locations have to be evaluated for Gardner’s syndrome. Features of this syndrome which inherited in an autosomal dominant pattern include multiple osteomas (especially of skull), sebaceous cysts and soft tissue tumors of the skin, intestinal polyposis and multiple impacted supernumerary teeth. This syndrome is considered as a precancerous condition, as the intestinal polyps frequently located in the colon and rectum if left untreated develop into colorectal adenocarcinoma. In our cases, clinically the patients were apparently healthy with no other skin or bone lesions, and the orthopantomogram of the jaws did not show any impacted or unerupted extra teeth. However, follow-up visits were advised to allow constant surveillance (2).

In both cases, removal of the bony protuberances was not indicated. Surgical intervention and removal is advised only when requested by patients for esthetic reasons, or when there is interference with oral function, and also to facilitate denture fabrication (3). Besides, tori and exostoses can be used as a source of autogenous bone graft for correction of intraoral bone defects (9, 12).

In summary, we have reported two cases with multiple bony overgrowths in the mouth which were diagnosed as tori and exostoses. The cause for its occurrence could not be clearly delineated; however an interesting finding in both cases was a casual association with frequent consumption of fish. This finding may require further exploration and may be an area of future research.