The presence of ridges on the sides of the tongue is a common observation. Medically, this appearance is known as a crenated or scalloped tongue. The distinctive, wavy pattern is not a disease itself but a physical symptom resulting from the tongue being pressed against the adjacent teeth. This indentation pattern signifies an underlying issue that causes the tongue to either swell slightly or habitually press against the dental arch. The cause can range from a simple habit to a systemic health condition, making it a valuable diagnostic sign.
Understanding Crenated or Scalloped Tongue
A scalloped tongue is characterized by indentations that line up precisely with the spaces between the teeth. These ridges typically occur along the lateral borders of the tongue, where pressure is greatest against the dental structures. The mechanism is purely mechanical: the soft tissue is compressed between the upper and lower teeth, causing the surface to mold into the shape of the opposing structure. This molding happens over time due to consistent contact, leading to the scalloped edge.
Direct Causes: Mechanical Stress and Oral Habits
The most common reasons for tongue scalloping involve mechanical forces or behavioral habits that increase pressure on the tongue’s margins. One frequent cause is bruxism, the habitual grinding or clenching of teeth, often occurring during sleep or in response to stress. This clenching action pushes the tongue outward against the teeth, creating the indentations. Stress and anxiety are frequently linked to this habit, as they cause subconscious muscle tension in the jaw and mouth.
Another significant contributor is the resting position of the tongue, known as tongue thrusting or other parafunctional habits. If the tongue habitually rests too far forward or presses against the lingual surfaces of the teeth during swallowing or speaking, chronic pressure is applied. This consistent, low-level pressure causes the soft tissue to conform to the shape of the teeth over time.
Dental structure can also play a role, particularly in cases of malocclusion or temporomandibular joint (TMJ) disorders. An irregular bite or a misaligned jaw joint changes the spatial relationship between the tongue and the teeth. This forces the tongue to press harder against the dental arch to maintain a comfortable resting position. Dehydration can also contribute by causing a slight, generalized swelling of the tongue. When the tongue tissue swells marginally due to lack of fluid intake, it occupies more space and is more likely to press against the teeth, especially during sleep.
Internal Causes: Systemic Health Conditions
While mechanical stress is a primary driver, the ridges can also signal a systemic condition that causes the tongue to enlarge, known as macroglossia. One common internal cause is hypothyroidism, where the thyroid gland does not produce enough hormone. Low thyroid function can lead to myxedema, a form of swelling that affects soft tissues, including the tongue, causing it to swell and press against the teeth.
Nutritional deficiencies can also contribute to tongue enlargement and scalloping. A lack of certain B-vitamins (B12, niacin, and riboflavin) or an iron deficiency can result in glossitis—the inflammation and swelling of the tongue tissue. This inflammation increases the tongue’s volume, forcing it into contact with the teeth and creating the ridges. Addressing these deficiencies often requires dietary changes or supplements.
Another medically relevant cause is obstructive sleep apnea (OSA). Individuals with OSA may subconsciously press their tongue against the lower teeth during sleep. This is an instinctive attempt to stabilize the lower jaw and keep the airway open. This sustained, nocturnal pressure leads to the formation of scalloped edges, suggesting the need for a comprehensive evaluation of breathing during sleep.
Seeking Professional Diagnosis and Management
If you notice persistent scalloping on your tongue, consulting a healthcare professional, such as a dentist or primary care physician, is the appropriate next step. Diagnosis of the underlying cause guides the management strategy, as treating the symptom alone will not resolve the issue. A dentist may perform an oral exam to check for signs of bruxism, such as worn tooth surfaces, or assess for malocclusion and TMJ issues.
If a systemic cause is suspected, a physician may order blood tests to check thyroid hormone levels or screen for nutritional deficiencies. Treatment for mechanical causes may involve a custom-fitted nightguard to reduce pressure from clenching or referral for myofunctional therapy to correct tongue posture. For internal causes, management focuses on treating the root condition, such as medication for hypothyroidism or supplements for confirmed deficiencies. Seek prompt medical attention if scalloping is accompanied by pain, difficulty swallowing, chronic fatigue, or unexplained weight changes.