What Problems are Caused by Non-Nutritive Sucking Habits?

Patient Presentation
A 4-year-old female came to clinic for upper respiratory tract symptoms. She had had green rhinorrhea for 3 days with a temperature maximum of 38.5°C. She had been pulling on her ears and her mother wanted her checked for a possible ear infection. She had not verbalized pain in her ears, throat or other places. Her mother denied any wheezing and there was minimal coughing. The past medical history showed impetigo and asthma. The social history revealed a difficult social situation with intermittent times of homelessness for the family and inconsistent health care.

The pertinent physical exam showed a happy female with normal vital signs and growth. She was sucking on a pacifier. HEENT showed copious rhinorrhea but normal tympanic membranes. Her oropharynx showed multiple caries and slightly protruding upper teeth. She had transmitted upper airway sounds to her lungs but no wheezing. She also was noted to have xerosis diffusely. The diagnosis of upper respiratory infection, caries and xerosis was made. The pediatrician discussed symptomatic treatment for the upper respiratory tract infection and xerosis. He also discussed oral hygiene, and with the help of the clinic social worker arranged for a dental appointment and transportation from the family’s temporary housing to the dentist. The patient’s clinical course over the next 4 months showed that she had been to the dentist and had started oral rehabilitation and restoration with some capping of her teeth. The family was still not as consistent as recommended with brushing her teeth and not giving her sweetened beverages in a sippy cup at night, but had stopped the pacifier use after the dentist had told them that her teeth were malaligned.

Facial growth is affected by the normal activities of breathing, sucking, chewing and swallowing. Sucking habits effects on facial structures “…depend[s] on the frequency, intensity and duration of the habits, the osteogenic development and the genetic endowment of the child.”

Breastfeeding assists normal development of the facial structures (mainly maxilla, mandible and dental arches) by proper muscle activity and tongue positions. With bottle, finger, or pacifier sucking, there is overuse of the chin and cheek muscles, underuse of the orbicular oris and masseter muscles, and malpositioning of the tongue which can impede proper facial growth.

Non-nutritive sucking (NNS) is a very common behavior in infants and young children. Prevalence varies “…based upon age, gender, ethnic origin, socioeconomic status, type of feeding, duration of breastfeeding, mother’s age, number of siblings and cultural level.” NNS objects such as pacifiers, thumb or fingers, or another external object such as blanket, or clothing are commonly used to help with self-soothing and for sleep. These may be used of other transitional objects (e.g. blankets, stuffed animals, etc.) which help with emotional regulation. However non-nutritive sucking habits (NNSH) can cause problems, mainly with dental malocclusion. Malocclusions can be seen in the deciduous teeth of even toddlers caused by NNSH. The American Academy of Pediatric Dentists recommends to cease the NNSH by age 3 stating “…professional evaluation has been recommended for children beyond the age of 3 years, with subsequent intervention to cease the habit initiated if indicated.”

“Malocclusion is the dental term for an improper bite relationship between the upper and lower teeth.” A basic description of the malocclusions is below along with planes of reference.

Vertical Relationship Problems

  • Frontal or vertical plane – plane running through the head perpendicular to the sagittal plane dividing the head in anterior and posterior halves.
    • Basically a plane from the top of the head to the bottom running through the ears. The face is separated from the back of the head by this plane.
    • Used to describe superior-inferior relationships
  • Overbite – the upper incisors overlap the lower incisors more than they should.
  • Open bite – the upper incisors do not overlap the lower incisors at all and there is an open space between them.

Transverse Relationship Problems

  • Transverse or horizontal plane – plane running through the head perpendicular to the sagittal and frontal planes dividing the head into upper and lower halves.
    • Basically a plane parallel to the ground running through the nose, across the top of the ears to the back of the head. The top of the head and eyes are separated from the lower part of the head and mouth by this plane.
    • Used to describe lateral or right-left relationships
  • Crossbites – a problem with the alignment of the upper and lower dental arches in the lateral plane. A tooth or teeth are located closer to the cheek or the tongue than they should be. These can be anterior or posterior.

Sagittal Relationship problems

  • Sagittal or median plane – plane running anterior to posterior dividing the head into right and left halves
    • Basically a plane running from the tip of the nose down the center of the head parallel with the spine. The left half of the head is separated from the right half of the head by this plane.
    • Used to describe anterior-posterior relationships
  • Retrognathic means the mandible and/or maxilla are positioned too far backward
  • Prognathic means the mandible and/or maxilla is positioned too far forward
  • Overjet – is when the anterior-posterior distances between upper incisors and lower incisors is increased.
    • Normally there is a small space between the upper incisors and lower incisors when the teeth are occluded that allows the teeth to overlap. An overjet is an increase in this space between the teeth and a reverse overjet or underjet is the opposite.

Learning Point
Malocclusions are very common with NNSH with just anterior overbite prevalence ranging from 15-84% in studies.
Pacifier use causes more problems in both anterior and posterior occlusions.
But as pacifier use is usually discontinued earlier than digit sucking, digit sucking can cause more longer term effects.
In one study at age 5 years the prevalence of malocclusion in deciduous teeth was 22% in the NNSH group verses 6.5% in the non-NNSH group. Anterior overbite is one of the most common malocclusions found in NNSH patients.

Digit sucking and nail biting also increases the risk of microbial exposure so potentially these children may have more infections. However there is data showing children with these habits are less likely to be atopic in childhood and adulthood suggesting this exposure is helpful to immune development.

Questions for Further Discussion
1. What are some techniques to stop NNSH?
2. Is there a correlation with NNSH and need for orthodontia in later life?
3. Is there a correlation with NNSH and dental caries or poor oral hygiene?

Related Cases

To Learn More
To view pediatric review articles on this topic from the past year check PubMed.

Evidence-based medicine information on this topic can be found at SearchingPediatrics.com, the National Guideline Clearinghouse and the Cochrane Database of Systematic Reviews.

Information prescriptions for patients can be found at MedlinePlus for these topics: Child Behavior Disorder and Child Dental Health.

To view current news articles on this topic check Google News.

To view images related to this topic check Google Images.

To view videos related to this topic check YouTube Videos.

American Academy of Pediatric Dentistry. Policy on Oral Habits. 2006. Available from the Internet at http://www.aapd.org/media/Policies_Guidelines/P_OralHabits.pdf (rev. 2006, cited 1/25/18).

Gallios, RG. Classification of Malocclusion. Slide set. Available from the Internet at http://www.columbia.edu/itc/hs/dental/D5300/Classification%20of%20Malocclusion%20GALLOIS%2006%20final_BW.pdf (cited 1/25/18).

Malocclusion. ToothIQ.com. Available from the Internet at https://www.toothiq.com/dental-diagnosis/malocclusion/ (rev. 2018, cited 1/25/18).

Isaacs D, Isaacs S. Transitional objects and thumb sucking. J Paediatr Child Health. 2014 Nov;50(11):845-6.

Chen X, Xia B, Ge L. Effects of breast-feeding duration, bottle-feeding duration and non-nutritive sucking habits on the occlusal characteristics of primary dentition. BMC Pediatr. 2015 Apr 21;15:46.

Rijpstra C, Lisson JA. Etiology of anterior open bite: a review. J Orofac Orthop. 2016 Jul;77(4):281-6.

Lynch SJ, Sears MR, Hancox RJ. Thumb-Sucking, Nail-Biting, and Atopic Sensitization, Asthma, and Hay Fever. Pediatrics. 2016 Aug;138(2).

Kolawole KA, Folayan MO, Agbaje HO, Oyedele TA, Oziegbe EO, Onyejaka NK, Chukwumah NM, Oshomoji OV. Digit Sucking Habit and Association with Dental Caries and Oral Hygiene Status of Children Aged 6 Months to 12 Years Resident in Semi-Urban Nigeria. PLoS One. 2016 Feb 18;11(2):e0148322.

Silvestrini-Biavati A, Salamone S, Silvestrini-Biavati F, Agostino P, Ugolini A. Anterior open-bite and sucking habits in Italian preschool children. Eur J Paediatr Dent. 2016 Mar;17(1):43-6.

Lopes Freire GM, Espasa Suarez de Deza JE, Rodrigues da Silva IC, Butini Oliveira L, Ustrell Torrent JM, Boj Quesada JR. Non-nutritive sucking habits and their effects on the occlusion in the deciduous dentition in children. Eur J Paediatr Dent. 2016 Dec;17(4):301-306.

Donna M. D’Alessandro, MD
Professor of Pediatrics, University of Iowa