Indian Journal of Dental Research

: 2012  |  Volume : 23  |  Issue : 5  |  Page : 680--682

Onychophagia (Nail biting), anxiety, and malocclusion

Avesh Sachan, TP Chaturvedi 
 Department of Orthodontics, Faculty of Dental Sciences, Institute of Medical Sciences, Banaras Hindu University, Varanasi, India

Correspondence Address:
Avesh Sachan
Department of Orthodontics, Faculty of Dental Sciences, Institute of Medical Sciences, Banaras Hindu University, Varanasi


Nail biting is a stress removing habit adopted by many children and adults. People usually do it when they are nervous, stressed, hungry, or bored. All of these situations are having a common phenomenon between them is anxiety. Onychophagia is also a sign of other emotional or mental disorders. It is a habit that is not easy to quit and reflection of extreme nervousness or inability to handle stressful conditions. This abnormal habit may cause various malocclusions associated with dentoalveolar segment of the oral cavity. Crowding and rotations of incisors are common with this habit.

How to cite this article:
Sachan A, Chaturvedi T P. Onychophagia (Nail biting), anxiety, and malocclusion.Indian J Dent Res 2012;23:680-682

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Sachan A, Chaturvedi T P. Onychophagia (Nail biting), anxiety, and malocclusion. Indian J Dent Res [serial online] 2012 [cited 2023 Feb 3 ];23:680-682
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Full Text

Nail biting or onychophagia is a common stress-relieving oral habit. Onychophagia, the habit of biting one's nails is commonly observed in both children and young adults. Nail biting includes biting the cuticle and soft tissue surrounding the nail as well as biting the nail itself. Onychophagy is a nail disease caused by repeated injuries of nails. Nail biting as auto destruction and onychophagy are its most aggressive forms. The need to bite or eat fingernails is related to a psycho emotional state of anxiety. A nail biting child is exhibiting an evolutionary disturbance related to the oral stage of psychological development. [1]

The problem is usually not observed before the age of 3 or 4 years. Most cases of nail biting or onychophagia are seen between the ages of 4 and 6 years; it stabilizes from 7 to 10 and increases considerably during adolescence, because this period is a time of crisis. To most adolescents, this is a difficult and even traumatic passage. Up to 10 years of age, the incidence of nail biting is relatively equal but thereafter it is observed that boys are significantly higher than girls as nail biters. [2]

Dentofacial or dentoalveolar functional abnormalities like nail biting can associated with other dentofacial conditions and should be diagnosed and managed according to requirements of clinical situation. Correction or control of this functional problem might involve alteration of behavior patterns and multidisciplinary treatment. Nail biting should be evaluated to identify specific concerns regarding stability and to suggest methods of retention to improve stability.


Nail biting, demonstrating anxiety made worse by tense moments, is seen as a reflex of emotional unbalances. [3] Nail biting has a sequence of four distinct postures.

The hands are placed close to the mouth and keep there for a few seconds to half a minute.The fingers are quickly tapped against the front teeth.A series of quick spasmodic biting follows, with the fingernails pressed tightly against the biting edge of the teeth.The finger is withdrawn from the mouth.

The basic cause of onychophagia is difficult to determine. Although it has been observed that nail biters have more anxiety than those who do not have the habit. People bite their nails during moments of stress. Children do it in moments of anguish, when they do not know a lesson, read sad stories, listen to horror stories, watching television, or talking on the phone. It can also be a learned behavior from family members. Nail biting is the most common of the typical "nervous habits," which include thumb-sucking, nose-picking, hair-twisting or pulling, tooth-grinding, and picking at skin.


When nail biting associated with other problems, it gets more complex, and requires specialized help. When a child swallows the bitten-off nails, stomach problems like stomach infection can develop, in addition to the hygienic aspect of nails, which are seldom clean, and various diseases can be transmitted. After adolescence, onychophagia is usually replaced by the habit of lip "pinching," chewing of pencils or other objects, nose scratching, or hair twirling. In adults, smoking or gum chewing seems to be a common substitute.

Nail biting children are at risk of developing malocclusion of the anterior teeth. Non-physiological forces acting on the teeth, such as those from nail biting, can speed up resorption or cause apical root resorption. [4] Dental examinations of these patients can show crowding, rotation, and attrition on the incisal edges of the mandibular incisors and protrusion of the maxillary incisors. [5] These malocclusions are created by pressures from the onychophagia habit. The forceful and continuous habit of nail biting causes alveolar destruction in the area of the involved teeth. [6] Chronic nail biting can produce small fractures at the edges of the incisors, and gingivitis might result from continued nail biting. [7]

Bacterial infection can occur from diseases of the nail such as onychomycosis and paronychia and nail biting might spread the infection to the mouth. A nail biter with oral herpes can develop herpetic whitlow of the bitten finger. [8] A positive aspect of nail biting is that fingernail growth is not retarded but it increases nail growth by approximately 20%, perhaps because frequent manipulation of the nail stimulates the circulation to the germinal area in the nail root. [9] Rarely, nail biting may be a symptom of obsessive-compulsive disorder (OCD). OCD symptoms are usually treated with medicines.


Several treatment measures may help to stop nail biting, some focus on behavior changes and some focus on physical barriers to nail-biting. To control or correct the nail biting habit, the patient must be motivated. Patient must be aware of the need to abandon the habit, and here the professional role acquires relevance, offering helpful suggestions in overcoming the addiction. Sudden suppression might introduce personality alterations. Some people spontaneously quit onychophagia because of fear of developing infections; others quit to imitate friends who have attractive nails. [10] No treatment is needed for mild cases of onychophagia. For more serious situations, treatment should involve removal of the emotional factors inducing the habit, in most cases; a little more attention, love, affection, and comprehension are enough to break the habit.

Outdoor activities requiring great physical effort might be indicated. Outdoor play and opportunities to use the mind, hands, and emotions in arts and crafts are recommended, since they function as tensions releasers. When the habit is corrected early, especially in mild cases before the permanent damage to incisal edge of incisors and sever rotations, the malocclusion will usually revert without treatment. [11] Application of a bitter-tasting commercial preparation to the nail, in the hope of stopping the habit, is ineffective; these procedures cause greater tension in young people. Techniques such as application of olive oil to the nails, make them soft and pliable, and removes the temptation to chew off nails with the teeth.

Keeping the nails well trimmed is another useful measure, so that poorly trimmed corners and cuticles are not temptations. For girls, having the nails manicured could have a positive and surprising result. Boys might apply bandages to their fingers, letting their friends believe they are treating injuries, rather than fighting onychophagy.

An effective alternative is to ask the patient to use the rubber bite piece when he or she feels the urge for nail biting or has anxiety. Chewing sugar-free gum, if not compulsively done, could also be a way to keep the mouth occupied and render the habit difficult or impossible. Occupying the hands with another activity, such as handicrafts or a musical instrument, might also be effective in keeping the hands away from the mouth. [12]

The best way to treat a nail biter is to educate them, stimulate good habits, develop conscious awareness, and thus guarantee effective results, because no other way to stop the habit is more efficient, intelligent, and satisfactory. During treatment, the child should be given emotional support and encouragement. A multidisciplinary approach should focus on efforts to build up the child's self-confidence and self-esteem. [13]


Nail biters have crowding, rotation, and attrition on the incisal edges of the mandibular incisors and protrusion of the maxillary incisors. Mild cases of onychophagia do not cause severe malocclusion. Severity of malocclusion associated with nail biting depends upon intensity, duration, and frequency of habit. Behavioral modification techniques, positive reinforcements, and regular follow-ups are important for the treatment of nail biting or onychophagia with a multidisciplinary approach, if necessary.


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