RECURRENT APHTHOUS ULCER (CANKER SORE)

Recurrent aphthous ulcers (RAUs) have following characteristics:

1. They are recurrent, painful, superficial oral ulcers that persist 8 to 14 days;

2. They are associated with a tender regional lymphadenopathv (swelling of lymph nodes in the head and neck area);

3. They heal spontaneously, usually without sequelae in healthy patients.

The causes and the course of the disease

Several theories about the cause of recurrent aphthous ulcers have been proposed; they include psychic, allergic, microbial, endocrine, hereditary, and autoimmune mechanisms.  Many dentists also find mechanical trauma play a role in the precipitation of these ulcers.

A study reported patients, who were challenged with certain foods, begins their ulcers. No causative effect was found on tomatoes, strawberries, or walnuts. Hay and Reade (1984) reported the results of their study clearly showed that some food ingredients contributed to the cause of some cases of recurrent aphthous ulcers.

The inheritance of recurrent aphthous ulcers was studied by Miller et al. (1980). Their results showed the incidence of the disease in children was significantly higher when RAUs were present in one or both parents. Another study reported that recurrent aphthous ulcers occurred more commonly in patients from higher socioeconomic groups.

Studies about the stress-related vitamin B12 and folate levels in recurrent aphthous ulcers have yielded conflicting results. Some found several RAU patients with decreased folate levels; others failed to find signilicantly lower serum levels of yitamin B12 or folate in RAU patients.

Currently it seems likely that the recurrent aphthous ulcers develop because of several different mechanisms. Studies showing shifts in immune balance are many.  Ferguson et al. (1981) reported the highest incidence occurred in menstruating women.

The clinical features

The recurrent aphthous ulcers, in the usual course of events, appear, regress, and heal within 4 to 10 clays. The patients are requested not to brush their teeth in the affected area until the lesions have completely disappeared.

However, in rare cases, the lesions may appear without remission for as long as 2 or 3 months. In these cases the patient has reported the lesions are constantly present but have shifted location during the disease. Necrotic tissue and uncharacteristic ulceration are usually present in these cases. Instead of forming on the oral mucosa, the lesions characteristically occur on the attached gingiva. Typically, the lesions usually disappear within 2 weeks after starting a regimen of tetracycline mouthwash, which wipes out the superimposed bacterial infection and allows healing.

The differential diagnosis

The dentists will need to distinguish between recurrent aphthous ulcers (RAU) and intraoral recurrent herpes simplex (IRHS) ulcers in most cases.  Herpangina and hand-foot-mouth disease are two other conditions that must be differentiated.

The recommended treatment

Most of recurrent aphthous ulcers resolve in 8 to 14 days without treatment. However, our Houston dentist recommends these:

1. Tetracycline mouthwash (an oral suspension of uncoated Achromycin crystals 250 mg/tsp in 5 ml water) to be flushed over the affected region for at least 2 minutes.

2. After cleaning the affected area with the tetracycline mouthwash, the ulcer is applied with a thick laver of triamcinolone acetonide in emollient dental paste (Kenalog in Orabase) after meals and before bed. Alternatively, aloe vera leaves may also be used.

3. Oral and topical analgesics are administered if necessary.

Our Houston dentist found the above treatment regimen gives satisfactory results. Other dentists reported that ulcer duration was shortened with chlorhexidine mouthwash.  Recently, a new hvdroxypropyl cellulose material (Zilactin) has been proposed for the treatment. In addition, various topical steroids have been promoted, but their benefits have not been consistent.