Canker sores, also known as aphthous ulcers, are small, painful lesions that develop on the soft tissues inside the mouth or at the base of the gums. They typically appear round or oval with a white or yellow center surrounded by a bright red border. Unlike cold sores, canker sores are not contagious and are not caused by the herpes virus. Minor trauma to the mouth is a recognized trigger for their development, meaning dental work can indeed cause these sores. This article explains the connection between physical trauma and canker sores and outlines how to manage them following a dental procedure.
How Physical Trauma Causes Canker Sores
The development of a canker sore is closely linked to an injury to the delicate lining of the mouth, called the oral mucosa. While the precise cause of recurrent sores involves an abnormal immune response, local trauma often acts as the initiating event. This minor injury breaks the protective surface layer, allowing the inflammatory process to begin.
When the oral tissue is damaged, the immune system reacts, leading to a localized inflammatory response. This reaction results in the characteristic ulcer, which can be triggered by mechanical abrasion or chemical irritation.
Stress, often associated with dental visits, also plays a contributing role by potentially weakening the immune system. Furthermore, certain chemical irritants, such as the foaming agent sodium lauryl sulfate found in some toothpastes, may increase susceptibility or prolong healing. The trauma from dental work provides the physical injury that initiates this chain reaction in susceptible individuals.
Common Dental Procedures That Act as Triggers
Many routine dental activities can inadvertently cause the minor trauma necessary to trigger an aphthous ulcer. The use of specialized tools, such as retractors and suction devices, during procedures like fillings or crown preparations can stress and abrade the soft tissues of the cheeks and lips. Prolonged opening of the mouth can also stretch the tissue, making it more vulnerable to injury from contact with instruments.
Orthodontic treatments are a frequent source of trauma, particularly when wires are adjusted or new brackets are placed, creating sharp edges that constantly rub against the inner cheek. Ill-fitting temporary appliances or sharp edges on newly placed restorations can also continuously irritate a specific area, leading to the formation of a sore. Procedures like deep scaling or root planing, which involve tools scraping near the gum line, may also cause abrasions to the surrounding gums or cheeks.
Even seemingly minor interventions, such as the injection of local anesthetic, can create a small wound at the injection site that develops into an ulcer. Any procedure that involves sustained contact or accidental friction against the non-keratinized (softer) tissue inside the mouth carries a risk of triggering a canker sore.
Managing Post-Procedure Sores and Promoting Recovery
Once a canker sore has appeared, the primary goal is to manage the discomfort and encourage the natural healing process, which typically takes between seven to fourteen days for minor ulcers. Pain relief can be achieved using over-the-counter topical numbing agents, such as gels or liquids containing benzocaine, which temporarily desensitize the nerve endings at the site of the lesion. Applying a protective barrier paste directly onto the sore can also help shield it from further irritation while eating or speaking.
Regular rinsing with a warm saltwater solution or a mixture of baking soda and water can soothe the area and help maintain oral hygiene around the ulcer. Patients should temporarily avoid consuming highly acidic foods, like citrus fruits and tomatoes, as well as spicy or abrasive items, which can intensify the pain and delay healing. If the sores are numerous, large, or do not show signs of healing within two weeks, a dentist may prescribe a specialized mouth rinse containing a steroid like dexamethasone to reduce inflammation, or a topical anesthetic like lidocaine for pain relief.