Habits leading to dental mal-alignment in children

Certain habits exhibited by growing children could lead to abnormalities in the position of teeth and jaws. Such habitual patterns of muscle behavior are associated with faulty jaw growth and teeth positions, disturbed breathing habits, difficulties in speech, imbalance in the facial muscles and psychological problems. The same habits, if persistent could also prevent the correction of the mal-aligned teeth also.

Following are few of the commonly seen habits:

Tongue thrusting

Tongue thrusting is the abnormal habit of placing the tongue between / against the inner aspect of the front teeth before, and during the act of swallowing. It could be seen as one or more of any of the following:

1) Forward placement of tongue during swallowing so that the tip of the tongue contacts the lower lip.

2) Inappropriate placement of the tongue between or against the front teeth during speech.

3) Forward positioning of the tongue at rest.

During a normal swallow, the tongue touches the roof of the mouth.  When it is positioned between the front teeth or thrust against the inner aspect of the front teeth, it becomes abnormal. Since swallowing is a continuous process which occurs 24 hours per day and about 2000 times per day, the tongue exerts momentary pressures varying from 1 to 6 pounds on the surrounding structures of the mouth which will push the teeth and bone forward.

How does a child develop tongue thrust?

It is natural for all the infants to swallow with the tongue between the gums (gum pads) in order to facilitate the suckling of the milk from a mother’s breast. The gum pads (on which the milk teeth erupt later) will not be in contact during the act of swallowing. Gradually as the child grows and matures, the swallowing pattern also matures and the tongue retracts its position and gets placed against the roof of the mouth during the swallow. The teeth will be in full contact during a mature (adult) swallow. If this natural progression does not happen, it results in tongue thrusting habit. Here, the muscles surrounding the teeth and lips (circum-oral muscles) are used to gain suction rather than those of the throat.

How do we recognize if the child has tongue thrusting habit?

A person with tongue thrust may show one or more of the following signs or symptoms:

1.      Facial grimace and/or pursing of the lips while swallowing. Lip puckering and lip licking prior to a swallow are indicative of tongue thrusting.  

2.      When at rest (while watching television or reading a book), an open mouth position with a forward tongue posture might be noted.

3.      A lack of vertical overlap of front teeth. Teeth might be far apart instead of showing a normal overlap.

4.      Protrusion of the front teeth because of the constant pressure from the tongue.

5.      Difficulty with speech, especially the s and z sounds.

There is also a type of tongue thrust which is to the sides of the mouth along with the frontal thrust (complex tongue thrust) and is most commonly due to a large sized tongue. Tongue size could be large because of a hereditary pattern or due to an underlying systemic disease which needs evaluation. Complex tongue thrust prevents the back teeth from erupting to the normal level preventing normal bite development.

Thumb sucking habit

It is observed that more than 50% of the children tend to indulge in sucking their thumb.  Some children place their fingers also inside the mouth along with thumb. Majority of them abandon the habit by the age of four years. If they continue it beyond the age of eruption of permanent teeth, it might lead to disturbance in the position of the erupting teeth. A sucking habit which is considered normal till a certain age will be considered harmful when persisted upon for a longer period of time.

The presence of clean nails and callus on the finger is normally suggestive of thumb sucking.

There are certain factors which decide whether these habits will create any disturbance in the position of teeth / jaw or not.

1.      How long does the child keep sucking the thumb/fingers?

The longer the duration, the more harmful it could be.

2.      How often does he indulge in the habit?

The more frequent the habit, the more disturbances it could create.

3.      How vigorously he sucks?

Mere placement of the thumb or fingers is not as harmful as vigorous sucking where his/her facial muscles are also involved.

How does the child develop the habit?

Studies have shown that thumb sucking is practiced even before the child is born. It is postulated that it is needed for the normal psychological development of the child. Child is supposed to obtain emotional satisfaction by indulging in thumb sucking and forceful prevention of that habit could lead to emotional insecurity. It is believed that children deprived of parental love and care can indulge in thumb sucking. But there are some researchers who believe that it’s a mere learned behavior and there are no psychological reasons behind the habit. Persistence of the habit beyond three to four years should alert the parents and a doctor’s opinion should be sought if it continues beyond the fourth or fifth year of life

 

What are the effects of persistent thumb sucking?

1.      Because of the position of the thumb and/ or fingers against the inner surface of the upper front teeth, they tend to get forwardly placed along with the upper jaw. Spaces might be present between the front teeth.

2.      The prominent teeth prevent the upper lip from full closure leading to an open lip posture.  Prominences of these forwardly placed teeth make them particularly vulnerable to accidental fractures.

3.      The heavy muscle forces due to the sucking can constrict the upper arch making it narrow and tapered.  

4.      The lower teeth might get pushed inward or outward depending on the way of placement of the fingers. If pushed inward, it leads to an increased distance between the upper and lower front teeth.

5.      A space between the upper and lower front teeth when the child bite which might lead to a compensatory tongue thrusting habit and difficulties in speech.

Mouth breathing

It is quite frequent to see children breathing through their mouth instead of their nose. The mouth breathing per se may not bring about much damages but the posture of the jaws during the procedure and the dryness created by constantly inhaled air could produce some damaging effects.

Why is it important for a child to breathe through the nose?

Nasal breathing has certain advantages over the mouth breathing like

1.      Purification of the inspired air:  The nose filters and humidifies the inhaled air before its entry into the lungs. When air is inhaled through the mouth, it is not cleaned, warmed and moistened.  

2.      Normal development of nose, windpipe, lung and the stomach muscles which assist in breathing occur with a regular nasal breathing. With oral respiration, the airway resistance is lacking and normal development of lungs and chest does not occur.

3.      Certain studies have shown that mouth breathers have 20 % more carbon dioxide and 20% less oxygen in the blood as compared to nasal breathers.

In addition to these, the child might develop a long face as he / she bends the neck forward in order to straighten the airway. Mouth breathing may lead to middle ear infections and the speech could acquire nasal tone. In extreme cases, the sense of smell could be diluted and with it taste sensation and appetite could get affected.

Why does a child breathe through the mouth?

It could be due to any one of the following reasons:

1.      The child has an obstruction in the nose due to some deviation in the normal structure (deviated nasal septum) or some medical reasons (nasal polyps, allergic rhinitis, tumours etc.) which prevents him / her from breathing through the nose.

2.      Some children will have short upper lip or prominent front teeth which prevent the normal lip closure. They will also tend to breathe through the mouth (by virtue of open lip posture) along with nasal breathing.

3.      Habitually some people tend to breathe through the mouth even after correction of any existing obstruction or prominent teeth.

What happens if the child continues mouth breathing?

1.      Molding action of upper lip is lost thereby resulting in forward placement and spacing of upper front teeth. 

2.      Tongue is suspended between upper and lower jaws resulting in narrow jaws due to lack of normal muscle balance between the tongue and facial muscles.

3.      The lower jaw (mandible) tends to be pushed into a more vertical and backward direction, causing an increased lower facial height and retruded lower jaw.

4.      Mouth breathers hold their lips apart. So the gums become air-dried and cause irritation.

5.      Saliva over the exposed gums becomes thick and viscous; debris collects on the gums as well as on the tooth surfaces.

6.      Along with the gums, tongue and roof of the mouth also become dry. Most commonly the patients present with swelling of the gums related to the front teeth subsequent to mouth breathing. It may even develop on the inner aspect of upper front teeth also, even in presence of good oral hygiene.

7.      Due to stagnation of debris and bacteria in the front teeth, they are often affected by decay.

How do we confirm whether a child is a mouth breather or not?

Clinical signs and symptoms are suggestive of a mouth breathing habit. It could be confirmed with certain small tests as given below.

1.      Ask the child to hold water in mouth. A child who is habituated with mouth breathing will not be able to hold water for more than few seconds as he needs to breathe through the mouth.

2.      Hold a piece of cotton or feather below the nostrils. It will move up for a mouth breather where as it will move down if the child breathes through the nose.

3.      Hold a double sided mirror below the nostrils. Fogging at the side of nostrils suggests nasal breathing whereas fogging at the side of mouth suggests mouth breathing.

Bruxism (clenching of the teeth)

Grinding or clenching of the teeth other than for chewing purposes is called Bruxism.

Why does the child clench his teeth?

It is believed that children with psychological disturbances or emotional stresses tend to grind their teeth during night. If the child does not have a comfortable bite, he might also indulge in clenching. Sometimes a mild pain associated with gums or an erupting tooth could also lead to a clenching habit as it is a human tendency to clench on teeth when put under stress or pain.

How do we recognize Bruxism?

Clenching or night grinding could be observed directly. Teeth might be showing abnormal wear patterns. Teeth might become loose in their sockets. The child might complain of soreness of the facial muscles when he gets up in the morning.

Lip biting, lip sucking and nail biting are also some of the less frequently encountered habits which if left unattended could lead to harmful effects on teeth and jaws.

Significance of identifying whether the child indulges in these habits or not

Habits need to be broken to allow normal development of the teeth and jaws. Persistence of the habit even after correction of the faulty teeth and jaw position could push them back to their original position leading to failure of the treatment.

Do they require any treatment?

Habits need to be treated under the guidance of a trained clinician, provided there is adequate parental support and cooperation from the patient. Treatment could vary from educating the child and parent regarding the consequences of continuation of the habit to the use of appliance therapy as and when the case requires. The harmful effects which are already present need to be corrected by a specialist doctor.