Canker Sores (Mouth Ulcers) Unbearably Painful? A Dentist Breaks Down the Causes and 3 Quick Relief Methods

Suffering from Mouth Ulcers? Too Painful to Eat? This common oral mucosal condition is medically known as Recurrent Aphthous Stomatitis. Although mouth ulcers typically appear as small, round or oval sores (white in the centre with red, swollen edges) and are generally non-contagious, the intense pain during a flare-up often makes eating or speaking extremely difficult. Most mouth ulcers heal naturally within 7 to 14 days. If an ulcer has not improved after 3 weeks, it is important to be alert to the possibility of other underlying conditions.

Why Do Mouth Ulcers Develop? 3 Key Internal and External Causes Explained

In dental clinical practice, patients frequently ask: "Why do I keep getting mouth ulcers lately?" The answer is rarely a single cause — it is usually the combined effect of the following factors:

1. Physical Trauma

This is the most direct cause.

• Everyday injuries: Brushing too vigorously and injuring the gums, or accidentally biting the tongue or cheek while chewing.

• Braces discomfort: Metal components of orthodontic appliances rubbing against the oral mucosa.

• Food irritation: Consuming overly rough (e.g. crisps), hard, or very hot foods that scratch the mucosal lining.

2. Nutritional Imbalance

The health of the oral mucosa reflects the body's nutritional status. Research shows that deficiencies in the following nutrients can slow mucosal repair and make mouth ulcers more prone to recurrence:

• Vitamin B12

• Iron

• Folic Acid

• Zinc

3. Immune System and Stress

The fast pace of modern life means that high stress levels and insufficient sleep can weaken the immune system and disrupt the oral microbiome. In addition, hormonal fluctuations before menstruation are a common trigger in women.

What to Do When a Mouth Ulcer Hurts? Your Dentist's Guide to Proper First Aid and Care

Although mouth ulcers heal on their own, proper care can significantly reduce pain:

1. Maintain oral hygiene (don't avoid brushing because of the pain): Many people avoid brushing due to discomfort, but this allows bacteria to accumulate and worsen inflammation. It is advisable to switch to a soft-bristled toothbrush and brush gently, and to rinse with warm salt water, which has mild antibacterial and anti-inflammatory properties that help protect the wound.

2. Dietary adjustments: Temporarily avoid spicy, highly acidic (e.g. lemon, tomato), very salty, or very hot foods. Opt for soft, easy-to-eat foods (such as congee or steamed egg), and drink plenty of water to keep the mouth moist and benefit from saliva's natural antibacterial properties.

3. Medicated relief: Over-the-counter mouth ulcer gels and patches typically contain local anaesthetics (such as Benzocaine) or corticosteroids, which form a protective barrier over the wound to shield it from irritants and relieve pain.

When Should You See a Dentist? Watch Out for Oral Cancer Warning Signs

While most mouth ulcers are benign, please seek professional dental advice if any of the following apply:

• Prolonged non-healing: The ulcer has not healed after 2 to 3 weeks.

• Spreading or worsening: The number or size of ulcers is increasing, accompanied by fever or swollen lymph nodes.

• Painless ulcer: An ulcer that is painless yet persistently unhealed may be an early sign of oral cancer.

• Caused by dental issues: If the ulcer is the result of prolonged friction from a chipped or sharp tooth, or ill-fitting dentures, dental treatment is necessary to resolve the underlying problem.

In summary, maintaining good oral hygiene, eating a balanced diet, and managing stress effectively are the cornerstones of mouth ulcer prevention.