Torus mandibularis (TM) is a common, non-cancerous condition characterized by bony growths appearing inside the mouth. These formations are generally benign and are frequently discovered incidentally during a routine dental examination. This article will explore the specific causes behind Torus Mandibularis, which are generally understood to result from a combination of inherited traits and mechanical forces.
Defining Torus Mandibularis
Torus Mandibularis is a dense, slow-growing bony nodule, or exostosis, found on the lower jawbone, the mandible. These growths are typically situated on the lingual side—the surface nearest the tongue—usually in the area near the canine and premolar teeth. They present as hard, rounded swellings covered by thin oral mucosa and are almost always asymptomatic. In approximately 90% of cases, these bony bumps occur bilaterally, appearing on both sides of the jaw, though their size may differ. The prevalence of TM varies widely across populations, with estimates suggesting they affect between 5% and 40% of the general population.
Primary Factors Influencing Development
The development of Torus Mandibularis is considered multifactorial, involving the interaction of genetic susceptibility and environmental factors. Current research suggests that the majority of the cause, approximately 70%, is attributable to environmental influences, while the remaining 30% is due to genetic factors. These growths represent a form of compensatory bone growth, known as hyperostosis, which is stimulated by excessive strain on the bone.
Genetic Predisposition
Genetic predisposition plays a fundamental role in determining an individual’s likelihood of developing the condition. The condition often exhibits familial patterns, appearing more frequently within certain families, and studies involving identical twins show a higher concordance rate than in fraternal twins. Although no single gene has been definitively isolated, this strong hereditary link suggests that some individuals possess a heightened genetic capacity for bone remodeling in response to stimuli.
Functional and Mechanical Stress
Functional and mechanical stress serves as the primary environmental trigger that stimulates the bone growth in susceptible individuals. Chronic clenching and grinding of the teeth, medically known as bruxism, are considered the most relevant local stresses. The powerful, sustained muscular forces generated during bruxism place excessive strain on the mandible, particularly in the premolar area. This constant, heavy masticatory force is thought to pressure the periodontal ligament, leading to new bone formation on the jaw’s inner surface as a reinforcing reaction. The size of the tori may even fluctuate throughout a person’s life, often correlating with periods of increased mechanical stress.
Clinical Significance and Management
Torus Mandibularis is a clinical finding that rarely causes symptoms and typically requires no treatment. Since the growth is slow and often small, it does not typically interfere with daily functions like speaking or eating. However, intervention may become necessary if the tori grow large enough to pose a practical complication for oral health or dental work. A dentist or oral surgeon may recommend surgical removal, a procedure called a torusectomy, under specific circumstances.
The most common reason for removal is when the bony protrusions interfere with the fitting or stability of a removable dental prosthesis, such as a full or partial denture. The tori can also develop repeated trauma from chewing or from hard foods, leading to chronic ulceration of the thin overlying mucosa, which can become painful. In these cases, the removal of the excess bone facilitates proper healing and allows for better long-term oral function.