Find a Registered Dental Hygienist


Knowledge Network

FACT SHEET: Down Syndrome (also known as “Down’s syndrome”, “DS”, and “trisomy 21”)

Date of Publication: June 20, 2019

Is the initiation of non-invasive dental hygiene procedures* contra-indicated?

  • No.

Is medical consult advised?

  • Yes, if previously undiagnosed Down syndrome is suspected1.
  • Yes, to assess for atlantoaxial instability that may need to be treated/managed prior to dental/dental hygiene therapy.

Is the initiation of invasive dental hygiene procedures contra-indicated?**

  • Yes, if the patient/client has any cardiac condition for which antibiotic prophylaxis is recommended in the guidelines set by the American Heart Association (AHA) unless the dental hygienist has consulted with either the patient/client’s physician, dentist, or registered nurse in the extended class and determined that it is appropriate to proceed if the patient/client has taken the prescribed medication per the AHA guidelines.

Is medical consult advised?

  • See above.

Is medical clearance required?2

  • Yes, for any cardiac condition requiring antibiotic prophylaxis.  Medical clearance may also be required for certain co-morbid conditions (e.g., significant seizure risk).

Is antibiotic prophylaxis required?

  • Possibly, because patients/clients with Down syndrome often have congenital heart disease. AHA antibiotic prophylaxis guidelines for infective endocarditis should be followed for patients/clients with unrepaired cyanotic congenital heart disease (including palliative surgical shunts and conduits) or repaired congenital heart disease with residual defects3 or prosthetic patches/devices within first 6 months of repair procedure.

Is postponing treatment advised?

  • Yes, if atlantoaxial instability cannot be appropriately managed in the dental hygiene setting.
  • Yes, if the patient/client exhibits behavioral signs/symptoms (e.g., aggressive or uncooperative behaviour) that may pose a risk during, or cause inability to perform, procedures.
  • Yes, if there is acute oral infection, in which case medical advice should be sought.
  • Possibly, if there is co-morbid epilepsy (depends on severity and level of control of the disease, including compliance with treatment regimen and presence/absence of oral pathology — such as tooth fractures — that may need to be addressed prior to dental hygiene treatment).

Oral management implications

  • Most patients/clients with Down syndrome can be successfully treated in the general dental/dental hygiene practice setting. Consultation with family, caregivers, and physicians is important in obtaining an accurate medical history and in determining who can legally provide informed consent for treatment.
  • Given the high prevalence of periodontal and gingival disease, the dental hygienist plays an important role in the maintenance of oral health. Frequent follow-up and establishing strict home care regimens (including supervision of oral hygiene procedures and dietary habits, as often indicated) are key. Nutritional counseling may be needed to emphasize noncariogenic foods and beverages as snacks.
  • Because intellectual impairment varies greatly amongst patients/clients with Down syndrome, in-office management and dental hygiene education should be tailored to the individual according to mental age as well as to the person’s caregiver, as applicable. Such tailoring of care should also consider possible co-existing visual, hearing, and/or motor impairments. The dental hygienist may need to speak particularly clearly, simply, and slowly and use visual aids. Active listening is desirable, because the patient/client may have difficulty speaking.
  • Common cognitive and behavioural problems include short attention span, impulsive behaviour, poor judgement, and slow learning.
  • Dental hygiene appointments should be scheduled at the best time of day for the patient/client, which is often early in the day when everyone is alert and attentive and when waiting time is reduced. Distractions in the oral care environment should be minimized. Skeletal cervical anomalies may require shorter appointments for comfort. Consistency (e.g., same staff, operatory, and appointment time) is conducive to building trust and cooperation. A pre-appointment (in person or phone) is helpful to discuss special needs prior to the first visit.
  • Atlantoaxial instability exists in 12% to 20% of patients/clients with Down syndrome4. Delay in recognizing, managing, or adjusting for this condition can result in irreversible spinal cord damage in patients/clients undergoing dental hygiene therapy (or general anaesthesia). The patient/client with atlantoaxial instability requires careful movement into the dental chair, giving special attention to the spine and neck. Pillows may be used to stabilize the patient/client and increase comfort, often directed by the caregiver.
  • Because hypotonia (low muscle tone) manifests as increased range of joint movement and motor function problems, the dental hygienist should consider this when positioning the patient/client and ensuring his/her comfort in the dental chair. The patient/client may also exhibit spastic movements and/or have limited neck movement and pain.
  • Lip balm during treatment can ease the strain on the patient/client’s fissured lips.
  • If the patient/client has hearing loss, the individual may wish to adjust or turn off hearing aids, because the sound of some instruments may cause auditory discomfort.
  • While persons with Down syndrome generally tend to be content and well natured, they can become aggressive if they are disoriented or confused. Occasionally, sedation or general anaesthesia may be required for procedures if the patient/client is unmanageable5.
  • Gag reflex may be increased during oral examinations — even in the anterior portion of the oral cavity — due to placement of the tongue and anxiety associated with any oral stimulation.
  • Hepatitis B antigen carrier status is higher than it is in the overall population.
  • A panoramic radiograph should be considered to determine whether teeth are congenitally missing. The patient/client may find this technique less threatening than individual films.
  • Persons with Down syndrome tend to learn better from visual rather than auditory teaching. Patients/clients who are capable of performing their own self-care should be encouraged to do so. Power toothbrushes are useful for some patients/clients with minimal motor control6.
  • Chlorhexidine or other antimicrobial agents should be considered for daily use, with the method of administration (e.g., rinsing, spraying, or via toothbrush) being tailored to the patient/client’s abilities. Rinsing may not be appropriate for the patient/client who has difficulty swallowing or expectorating.
  • Tongue brushing should be considered for inclusion as part of the daily oral hygiene regimen.
  • Preventive measures, such as topical fluoride and fissure sealants, should be tailored to the patient/client’s needs and abilities (e.g., fluoride toothpaste versus gel versus rinse).
  • Primary teeth should be maintained as along as possible. Space maintainers are a consideration where teeth are missing.
  • High-functioning children may be candidates for orthodontic intervention and maxillofacial surgery, as required. However, braces and orthodontic treatment may be best deferred to allow for speech development which can be delayed by orthodontic appliances.
  • Because physical abuse often presents as oral trauma and occurs more commonly in persons with developmental disabilities than in the general population, the dental hygienist should be alert to suspicious oral trauma during the examination. Findings should be noted in the chart and any suspected abuse or neglect in children should be reported to the Children’s Aid Society as required by law7.

Oral manifestations

  • Early onset, severe periodontal disease is the most significant oral health issue, with up to 90% of patient/clients being affected8. However, dental caries rates are not typically elevated in children and young adults despite poor oral hygiene9.
  • The mouth is typically small.
  • Hypodontia10, microdontia, abnormally shaped teeth (small “peg” lateral incisors and both root and crown malformations, typically with decreased root to crown ratio), and malposition and crowding of teeth (particularly anterior) are common secondary to developmental and eruption anomalies. Furthermore, eruption of primary and secondary dentitions is delayed in 75% of patients/clients11, often accompanied by abnormalities in eruption sequence.
  • Enamel hypocalcification occurs in about 20% of persons with Down syndrome.
  • Premature loss of teeth (particularly the mandibular incisors) is common, resulting from loss of alveolar bone.
  • Relative mandibular prognathism occurs given hypoplasia of the maxilla and sphenoid bones that results in a typically flattened midface.
  • Malocclusion is common due to the small mid-face and relative mandibular protrusion. This manifests as apertognathia (open bite)12, cross-bites (particularly posteriorly, but also anteriorly), crowding of teeth (particularly anteriorly), and impacted canines.
  • The palate may appear highly vaulted and narrow, resulting from increased thickness of the hard palate. This thickness restricts the space the tongue can occupy and consequently affects the ability to speak and chew.
  • Cleft palate and lip, as well as bifid uvula, are occasionally seen.
  • Fissured tongue is frequently seen as the patient/client ages, along with enlarged circumvallate papillae. Cracks in the tongue contribute to halitosis.
  • Macroglossia is usually relative due to the small oral cavity, but true macroglossia also occurs.
  • Open-mouth posture and mouth breathing are common due to low muscle tone and large tongue, and because a narrowed oropharynx and enlarged tonsils and adenoids tend to comprise the upper airway. Open-mouth posture is frequently accompanied by a protruding tongue and drooling.
  • Cracked, dry lips result from habitual mouth breathing and a protruding tongue.
  • Aphthous ulcers, oral candidiasis, and acute necrotizing ulcerative gingivitis are common, because a compromised immune system leads to more frequent oral and systemic infections.
  • Tongue thrusting, bruxism, and teeth clenching are common. Temporomandibular joint dysfunction also occurs due to laxity of supporting ligaments and muscles.
  • Dental trauma is frequent due to impaired motor development that results in falls and accidents.
  • Tooth loss occurs in about 50% of patients/clients due to the high prevalence of periodontal disease. Loss of anterior teeth is particularly common during the early teens.
  • Xerostomia may occur due to mouth breathing, as well as secondary to certain medications used to treat hypertension (e.g., calcium channel blockers).
  • Gingival hyperplasia is seen in patients/clients taking certain anticonvulsant medications (particularly phenytoin).
  • Pica (ingestion or mouthing of non-edible items) is common in children with DS.

Related signs and symptoms

  • Down syndrome is a common, lifelong, incurable, and usually easily recognizable congenital condition — with physical and mental traits — that results from aberration in chromosome 2113.
  • In Canada, 1 in 781 live births results in Down syndrome determination14, with risk increasing with advanced maternal age at the time of conception. About 45,000 Canadians live with Down syndrome.
  • While approximately 50 specific physical characteristics are associated with Down syndrome (with increased risk of abnormalities in nearly every organ system), not every patient/client manifests all of these, and they may occur in various degrees.
  • Persons with Down syndrome usually have a characteristic facial appearance that includes mid-face skeletal deficiency, with orbital hypertelorism (widely spaced eyes) flattened nasal bridge, and flat facial profile. The small nose is recessed with upturned nostrils, and deviations in the nasal septum are frequent. The head appears small, and the skull is shortened in the anterior-to-posterior diameter (i.e., from forehead to crown). Hence, there is a prominent forehead and flat occiput. Frontal and sphenoid sinuses are usually absent, and the maxillary sinuses are hypoplastic in more than 90% of patients/clients. Chronic sinusitis and rhinitis may be present.
  • Eyes are almond shaped, with upward slanting palpebral fissures15 and epicanthal folds16. Brushfield’s spots17 are often present in the iris. Ocular disease affects about 50% of patients/clients, including congenital cataracts, convergent strabismus (crossed eyes), amblyopia (“lazy eye”), nystagmus (involuntary eye movement), keratoconus18, refractive errors, and tear duct abnormalities19.
  • Ears are often small, low-set, and abnormal in structure and contour, resulting in a square or round appearance. Mild to moderate hearing loss is common, resulting from conductive abnormalities, persistent fluid in the middle ear, and/or chronic or recurrent middle ear infections.
  • The neck is usually short, with excess skin posteriorly at the nape.
  • Hands are usually short and wide, with a single, deep crease across the palm. Fingers are short, and nails are hyperconvex.
  • Height is usually significantly shorter than normal, and there is a tendency towards obesity.
  • Intelligence level varies from near normal to noticeably low20, and delayed language and speech development is common. Additionally, hearing and/or visual problems may affect learning and development. Despite IQ limitations, most children with DS develop into happy and, in some cases self-reliant, individuals.
  • Due to poor muscle tone, a child with Down syndrome may be slow to learn to sit, stand, and walk. Muscle tone tends to improve by late childhood.
  • Skeletal problems include scoliosis (curvature of the spine), rib and pelvic abnormalities, hip dislocation, and patellar subluxation (unstable kneecap). Excessive external hip rotation and abduction lead to wide-angled gait and widespread legs when sitting.
  • Congenital heart disease (CHD) is present in about 50% of persons with Down syndrome21. Mitral valve prolapse is experienced by about half of all adults with Down syndrome.
  • Endocrine disorders involving the thyroid, pituitary, or adrenal glands are common. Thyroid dysfunction (both congenital and acquired hypothyroidism and less frequently hyperthyroidism) occurs in 50% or more of patients/clients. Obesity occurs at elevated rates.
  • Seizure activity (especially generalized tonic-clonic seizures) after age 20 years occurs at an elevated rate compared with the general population.
  • Respiratory tract infections and other infectious diseases occur at elevated rates, likely due to aberrant immune system function.
  • Gastrointestinal problems may include celiac disease, gastro-esophageal reflux disease (GERD), chronic constipation, and intestinal blockages, the latter manifesting as pronounced vomiting.
  • Obstructive sleep apnea affects nearly half of patients/clients with Down syndrome.
  • Leukemia (both acute lymphocytic and acute myeloid) occurs at an elevated rate, particularly during childhood.
  • Dementia ultimately affects about 30% of patients/clients with Down syndrome, and early aging is common.
  • While recent technological advances have markedly improved life expectancy for many persons with Down syndrome (with affected persons generally living into their fifties)22, infants with significant congenital heart disease continue to have a poor prognosis. Common causes of death include cardiopulmonary complications, gastrointestinal malformations, and leukemia.

References and sources of more detailed information

Date: October 8, 2018
Revised: April 2, 2023


1 Such initial detection is unlikely to occur in the dental hygiene setting due to well-defined physical characteristics usually being identified at birth or shortly thereafter. However, diagnosis may be delayed if the patient/client has mild mosaic Down syndrome and hasn’t previously had prenatal or postnatal genetic screening or testing. Mosaicism in Down syndrome means that some cells of the body have an extra chromosome 21 while other cells have the normal number of chromosomes.
2 Although patients/clients with Down syndrome tend to have defects in their immune system, these are not typically significant enough to warrant medical clearance.
3 Residual defects include persisting leaks or abnormal flow at or adjacent to a prosthetic patch or prosthetic device.
4 This is caused by increased laxity of the transverse ligaments between the odontoid process and the axis. Most patients/clients with Down syndrome have no overt signs/symptoms of atlantoaxial instability, and radiographic examination should occur by 3 years of age. Spinal cord compression may manifest as difficulty walking, abnormal gait, extremity weakness, spasticity, limited neck movement, torticollis (head tilt), lack of coordination, hyperreflexia, or sensory deficits.
5 Note that in-office sedation may be inappropriate for some persons with Down syndrome due to small airway, low muscle tone causing airway collapse, and large tongue.
6 Some persons with developmental disabilities find it difficult to tolerate the vibration.
7 in accordance with Ontario’s Child and Family Services Act
8 A defective immune system is thought to contribute to rampant and early onset periodontal disease. The disease is not proportional to oral hygiene, and it is high even when compared to persons of the same age with other intellectual disabilities.
9 This seeming contradiction may be due to the greater buffering capacity of saliva (elevated bicarbonate ion) seen in persons with Down syndrome and/or due to the ability to control dietary intake in home and institutional settings. Also, small-sized teeth with wider spaces between them facilitates the removal of plaque. In contrast, some adults with Down syndrome are increased risk of caries due to xerostomia and cariogenic food choices.
10 The most common missing teeth are third molars, lateral incisors, and mandibular second bicuspids.
11 Babies with Down syndrome typically get their first teeth at 12 to 14 months, and sometimes as late as 24 months of age. A child with Down syndrome may be 4 or 5 years old before all primary teeth come in. The anterior permanent teeth and permanent 6-year molars may not erupt until 8 to 9 years of age. In some children, primary teeth are retained until age 14 or 15 years.
12 Apertognathia is characterized by premature occlusion of posterior teeth in the absence of anterior occlusion.
13 The most common chromosomal abnormality in humans, Down syndrome usually results from nondisjunction that results in an extra chromosome (94% of cases), with translocation (3%), mosaicism (2%), and very rare chromosomal abnormalities (1%) comprising the rest of cases. In 1/3 of cases resulting from translocation, there is a hereditary component, but this only accounts for 1% of all cases of Down syndrome. Persons with mosaicism may have more subtle features of the syndrome.
14 Many affected fetuses spontaneously abort during early pregnancy, and some women choose termination of pregnancy following prenatal screening.
15 Palpebral fissures are the medial and lateral openings between the eyelids.
16 An epicanthal fold is a skin fold of the upper eyelid covering the medial corner of the eye.
17 Brushfield spots are small white or brownish gray speckles on the periphery of the iris due to aggregation of connective tissue.
18 Keratoconus is a progressive eye disease in which the cornea thins and bulges into a cone shape. This causes distorted vision.
19 Regular ophthalmologic monitoring is important.
20 Many adults with Down syndrome function at the level of an 8- to 10-year-old.
21 CHD defects in children with Down’s syndrome include atrioventricular septal defect (most common, and which is often accompanied by defects in the mitral and tricuspid valves), ventricular septal defect, persistent ductus arteriosus, Tetralogy of Fallot, and atrial septal defect. Before the age of 4 months, an infant with Down syndrome should receive an electrocardiogram (ECG) and echocardiogram, followed by paediatric cardiologic consultation if cardiovascular abnormalities are detected.
22 In North America, life expectancy has increased from 25 years in 1983 to 60 years today.

* Includes oral hygiene instruction, fitting a mouth guard, taking an impression, etc.
** Ontario Regulation 501/07 made under the Dental Hygiene Act, 1991. Invasive dental hygiene procedures are scaling teeth and root planing, including curetting surrounding tissue.