Canker Sores and Dry Mouth: What's the Connection?

Canker sores (aphthous ulcers) do not directly cause dry mouth (xerostomia). They are distinct conditions with different etiologies, though they can coexist or share triggers.

Canker Sores

• Small, round/oval ulcers with yellow-white center and erythematous halo.
• Non-contagious, recurrent.
• Triggers: Stress, trauma (biting, dental work), food sensitivities (citrus, gluten), hormonal changes, nutritional deficiencies (B12, iron, folate, zinc), SLS in toothpaste, immune dysregulation.
• Self-limited: 7–14 days. Topical corticosteroids, barrier pastes, laser therapy for pain.

Dry Mouth (Xerostomia)

• Subjective sensation of oral dryness due to reduced salivary flow (hyposalivation).
• Causes: Medications (anticholinergics, antihistamines, antidepressants, diuretics – #1 cause), Sjögren's syndrome, radiation to head/neck, diabetes, dehydration, mouth breathing, aging.
• Complications: Caries, candidiasis, dysphagia, taste alteration, mucosal trauma.

Overlap / Interaction

• Xerostomia → loss of salivary protection → ↑ frequency/severity of aphthae.
• Shared triggers: Stress, medications, nutritional deficiencies, autoimmune conditions.
• SLS-free toothpaste helps both.

Management

• Hydration, humidifier, sugar-free gum/xylitol lozenges (stimulate saliva).
• Saliva substitutes (carboxymethylcellulose).
• Review medications with prescriber.
• Treat underlying cause (e.g., Sjögren's, diabetes).
• Topical therapy for aphthae as above.

See dentist/physician if ulcers >2 weeks, recurrent (>6/yr), large (>1 cm), or with systemic symptoms.