Thumb and Finger Sucking - When to Seek Help

Written by Dr. Brooke and Dr. Hadawi

Sucking is a normal, instinctive behaviour that is essential to survival. The habit is derived from a physiological need for nutrients, and is one of the first neurological reflexes to develop in humans. Generally, sucking habits during the first five years of a child’s life have little or no long term effects. If the habit persists beyond the time the adult teeth begin to grow in, numerous problems in a child’s bite may start to develop. These problems cover a wide spectrum of severity, both in terms of tooth position and jaw development. For this reason, it is recommended that parents have their children examined by an orthodontist around age seven.

The severity of bite problems which arise from any thumb and digit sucking habit are dependent upon the intensity, duration and frequency of the habit. Any activity that is minimally practiced once per day, for six hours or more, with enough force to draw milk or formula is enough to create significant changes in your child’s bite if left untreated.

Habit induced bite problems include anterior open bites, caused by a blockage of the eruption of both upper and lower front teeth. This form of dental pattern may be accompanied by a tongue thrust habit, where the tongue becomes wedged between the upper and lower teeth during swallowing. An excessive overjet (a.k.a overbite) from flared upper front teeth, collapsed lower teeth and a lower jaw growth disturbance may also develop as a result of sucking habits.   

Orthodontic intervention is often used as a last recourse to eliminated digit sucking habits when reminders and positive reinforcement have failed. Orthodontic habit breaking appliances work by making your child conscious of the sucking habit and by reducing any pleasurable sensations associated with digit sucking. These appliances primarily interfere in the placement of fingers or thumbs into your child’s mouth, and may act to restrain the tongue during swallowing. Older children sometimes stop the habit because they dislike the appearance of the appliance, requesting its removal as soon as possible. Any appliance should remain in place for at least three months after the habit is eliminated. Premature removal of an appliance may result in your child regressing back the digit sucking habit.

Commonly used orthodontic appliances used for habit breaking are the Bluegrass Appliance and the Palatal Crib. Both of these appliances are cemented to the teeth, therefore do not rely on your child’s compliance for their effects. The Bluegrass Appliance consists of a small plastic bead suspended onto a metal wire fitted to the roof of the mouth. This bead interferes with the placement of the digit into the mouth, permitting the tongue to assume it proper position (the roof of the mouth).

The Bluegrass Appliance does not offer any significant restraint against tongue thrust activities.  In severe situations of combined digit sucking and tongue thrusting habits, the Palatal Crib is the appliance of choice.  This appliance is similar in design to its Bluegrass counterpart, but differs to the extent that the plastic bead is replaced by a soldered metal “fence”. The Palatal Crib interferes with digit placement and completely eliminates tongue thrusting by trapping the tongue behind its downward directed fence.  It is important to teach your child that these appliances are not to act as punishments, but as reminders to stop the bad habit.

Prolonged digit sucking habits can have a negative impact on dental, skeletal, speech and emotional development. Children can be helped to eliminate their sucking habits effectively, without coercion, and in a positive way if their treatment is initiated at the correct time. It is therefore paramount, that children be seen by an orthodontist around the age of seven years.


Figure  A. Anterior openbite caused by finger sucking.
B. Finger sucking habit demonstrated by patient.

Dr. Kelly Brooke and Dr. Hisham Badawi are certified specialists in orthodontics and dentofacial orthopaedics. Questions regarding the subject of digit sucking, can be directed towards either, Dr. Brooke or Dr. Badawi care of: SMILE ELEMENTS ORTHODONTICS, Unit 140, 12024 Symons Valley Road NW, Calgary, AB T3P0A3, Phone: 730-6400.