Down syndrome

Oral health effects

• Early-onset, aggressive periodontal disease

  Periodontal disease is the most significant oral health problem in this population, affecting an estimated 90-96% of adults, with onset often in the teens and progression despite good plaque control.

  Mechanism: Innate/adaptive immune dysfunction (T-cell deficiencies, impaired neutrophil chemotaxis/phagocytosis), elevated gingival matrix metalloproteinases, and increased Th17-driven cytokine activity accelerate periodontal breakdown.

  Clinical management: Shortened recall intervals, reinforced caregiver-assisted hygiene, and a low threshold for non-surgical periodontal therapy.

• Large-appearing tongue (macroglossia, usually relative)

  The tongue often appears disproportionately large for the mouth; true macroglossia occurs in only about 8% of cases, with the remainder being 'relative' macroglossia from an undersized oral cavity.

  Mechanism: Midface/maxillary hypoplasia narrows the palate and oral cavity while tongue size is closer to typical; generalized hypotonia promotes a forward, protruded tongue posture.

  Clinical management: Consider contribution to open bite, mouth breathing, and airway risk (relevant to sedation planning); orofacial myofunctional approaches may be considered.

• Late-arriving and congenitally missing teeth (delayed eruption, hypodontia)

  Eruption of primary and permanent teeth is frequently delayed by up to several years and may occur out of the typical sequence; congenitally missing teeth occur roughly 10x more often than in the general population.

  Clinical management: Baseline and periodic radiographs to track eruption and agenesis, with orthodontic referral and space-maintenance planning as needed.

• Misaligned bite (malocclusion)

  Nearly universal occlusal disharmony is reported, most often Class III skeletal relationships and anterior open bite, from midface/maxillary hypoplasia and reduced orofacial muscle tone.

  Clinical management: Early orthodontic evaluation given the near-universal prevalence in this population.

• Bruxism and associated dental wear

  Parafunctional grinding is common and produces pronounced occlusal wear and reduced vertical dimension; it has also been implicated in failure of immediately-loaded dental implants.

  Clinical management: Occlusal splint/nightguard where tolerated; factor bruxism into restorative and implant treatment planning.

• Mouth breathing, open-mouth posture and fissured tongue/lips

  Low muscle tone, a small midface and narrow nasal airway lead to mouth breathing and an open-mouth posture; tongue and lip changes such as deep fissuring are common and trap plaque and food.

  Clinical management: Include gentle tongue cleaning in home care, watch for dry, inflamed anterior gingiva and cracked lips (recommend lip balm), and consider fluoride varnish where mouth breathing dries the teeth.