How long does mucositis last?

Sandra asked how long before the mouth ulcers would stop after her chemo/radiotherapy.

In a study (Long-term oral Candida colonization, mucositis and salivary function after head and neck radiotherapy. ) that followed the long-term effects of radiation therapy of head and neck malignancies on oral yeast colonization, mucositis and salivary function, examiner-rated mucositis and patient-rated xerostomia showed no significant recovery after 6 or 12 months. In this prospective study, 32 patients had radiation therapy of a malignancy of the head and neck. In all patients the salivary glands lay within the radiation field and the patients had at least five teeth. The first examination was performed after oral hygiene instruction and removal of questionable teeth before the start of radiotherapy. The following examinations were conducted after 3, 6, 9 and 12 months.