Pediatric Dentist in Ontario

What Is the Purpose of the Tongue-Thrust Reflex in Infants? | Ontario Children's Dentist

Newborns are at a huge disadvantage. They can move their arms and legs and wave hands and feet in the air. They can cry. They can pee and poop. But only with the assistance of adults can they eat. They are totally dependent on their parents for continued life.

Nature has, however, provided them with a few tricks up their non-existent sleeves. They have reflexes, automatic reactions to certain types of stimulus. These reflexes, such as the tongue-thrust reflex, are all they have to help them survive.

Newborn Reflexes

  • Rooting reflex - If the cheek, or especially the corner of the mouth, is touched gently, the child will turn its head in that direction. This is the reproduction of the reflex that occurs when the baby's mouth touches the nipple or the skin of the breast. The baby will 'root' in that direction, making it easier to find the nipple. The infant will make sucking motions with its mouth to encourage the mother to feed it. The reflex develops in the fetus at about 28 weeks gestational age. It is an involuntary motion that will last for the first four to six months of the infant's life. Then the brain has developed enough that the movement becomes voluntary. Persistence of the involuntary movement beyond six months can indicate brain abnormalities.
  • Sucking reflex - This reflex is triggered when the roof of the mouth is touched, as by a nipple. The baby takes the nipple, whether human or bottle, and squeezes it between the tongue and the roof of the mouth. There is another component to this reflex - breathing. Coordinating the maintenance of suction, the withdrawal of liquid from the breast, while keeping a clear airway, generally goes together well. However, some babies may have problems. Your pediatrician will be able to help. The sucking reflex doesn't develop in the fetus until about 32 weeks and it isn't fully developed until 36 weeks. Premature babies may have difficulty sucking for the first few weeks.
  • Tonic neck reflex - When you turn a baby's head to one side, you will see the arm on that side stretch out and the arm on the other side curl up. It looks like a fencer's pose and is sometimes termed 'the fencer's reflex'. This reflex lasts until about 6 months of age and then disappears.
  • Grasp reflex - If you place your finger in a baby's palm, those tiny fingers will close tight around it. When the palm is touched, the fingers curl in and hold on tight. This reflex disappears at about 5 to 6 months.
  • Babinski reflex - This is basically the same as the grasp reflex, except that it's in the foot.
  • Stepping reflex - while holding the baby in the air, if the foot is touched to a firm surface, the baby will begin 'stepping'. It will place one foot in front of another. The baby cannot stand, however, at this age, let alone walk. This is a reflex to help it reach the mother's breast. It disappears at about 2 months.
  • Moro reflex - This is the 'startle' reflex, a reaction to a sudden noise or movement that startles the infant. The head will be thrown back, arms and legs will be spread wide, and the child will begin to cry. Then it will draw the arms and legs in to its body as it relaxes. The reflex is generally present at 30 weeks gestational age. It disappears normally at 3 to 4 months. A weak Moro response or an asymmetrical response is cause for concern.
  • Tongue-thrust reflex - Some researchers feel that this is part of the sucking reflex. Others consider an independent involuntary act. When something solid is placed on the baby's tongue before 4 to 6 months of age, the tongue will push the object out. This is also called the 'extrusion' reflex and prevents the baby from choking. The baby simply doesn't have sufficient control of the throat muscles to swallow anything more than liquids until age 5 or 6 months. When the tongue-thrust reflex disappears, your baby may be ready to handle soft foods.

When any of these involuntary reflexes persist in a baby, there is reason for concern. Sometimes babies will persist with the tongue-thrust reflex into early childhood. This may be evidence of a congenital abnormality, but it is usually due to habit. This habit, however, can cause significant problems with the development of the mouth and with teething. It can also interfere with the acquisition of language skills, causing a lisp.

Early Infant Oral Care

If the tongue thrust continues past 6 months, the child needs to be evaluated. Starting with your pediatrician is always a good idea. The pediatrician may recommend that you take the baby to a children's dentist or orthodontist for infant oral care. The earlier treatment is started, the less damage is done. If not treated, tongue thrust can cause malformations of the teeth.

Persistence of the tongue-thrust reflex may indicate an underlying problem.

  • Allergies, especially associated with swelling of the tonsils and adenoids, can force the tongue forward.
  • Thumb sucking for a long time can cause abnormal patterns in the movement of the tongue.
  • Reverse swallow or orofacial muscular imbalance is a condition in which the tongue protrudes between the teeth at rest and when swallowing.
  • Tongue-tie, where there is a short band of tissue beneath the tongue, is also thought to contribute.

If you're concerned about your child's tooth development, seeing a children's dentist is wise. A children's dentist is the best kids' dentist. They are the experts in pain-free dentistry and the best cosmetic dentists for kids. In Ontario, Canada, the Ontario children's dentist to go to is at the Kids Dental Specialty, where they start with infant oral care and follow their patients through the years and growth. Call and make an appointment for your child today.