sterilizing agent and cauterizing material, and it is also present in some over-the-counter agents intended to treat aphthous ulcerations. mucosal necrosis has been reported to occur with concentrations of 0.5%. other materials used in endodontics are also caustic, which is part of the reason why use of a rubber dam is now recommended. irradiation as a result of radiotherapy to the mouth, radiation-induced stomatitis may develop, which can be associated with mucosal erosions and ulceration. if the salivary glands are irradiated, there may also be xerostomia (dry mouth), making the oral mucosa more vulnerable to frictional damage as the lubricating function of saliva is lost, and mucosal atrophy (thinning), which makes a breach of the epithelium more likely. radiation to the bones of the jaws causes damage to osteocytes and impairs the blood supply. the affected hard tissues become hypovascular (reduced number of blood vessels), hypocellular (reduced number of cells), and hypoxic (low levels of oxygen). osteoradionecrosis is the term for when such an area of irradiated bone does not heal from this damage. this usually occurs in the mandible, and causes chronic pain and surface ulceration, sometimes resulting in non-healing bone being exposed through a soft tissue defect. prevention of osteradionecrosis is part of the reason why all teeth of questionable prognosis are removed before the start of a course of radiotherapy. aphthous stomatitis an aphthous ulcer on the labial mucosa (note erythematous "halo" surrounding lesion) main article: aphthous stomatitis aphthous stomatitis (also termed recurrent aphthous stomatitis, ras, and commonly called "canker sores") is a very common cause of oral ulceration. 10–25% of the general population have this non-contagious condition. three types of aphthous stomatitis exists based on their appearance, namely minor, major and herpetiform major aphthous ulceration. minor aphthous ulceration is the most common type, presenting with 1–6 small (2-4mm diameter), round/oval ulcers with a yellow-grey color and an erythematous (red) "halo". these ulcers heal with no permanent scarring in about 7–10 days. ulcers recur at intervals of about 1–4 months. major aphthous ulceration is less common than the minor type, but produces more severe lesions and symptoms. major aphthous ulceration presents with larger (>1 cm diameter) ulcers that take much longer to heal (10–40 days) and may leave scarring. the minor and major subtypes of aphthous stomatitis usually produce lesions on the non-keratinized oral mucosa (i.e. the inside of the cheeks, lips, underneath the tongue and the floor of mouth), but less commonly major aphthous ulcers may occur in other parts of the mouth on keratinized mucosal surfaces. the least common type is herpetiform ulceration, so named because the condition resembles primary herpetic gingivostomatitis. herpetiform ulcers begin as small blisters (vesicles) which break down into 2-3mm sized ulcers. herpetiform ulcers appear in "crops" sometimes hundreds in number, which can coalesce to form larger areas of ulceration. this subtype may cause extreme pain, heals with scarring and may recur frequently. the exact cause of aphthous stomatitis is unknown, but there may be a genetic predisposition in some people. other possible causes include hematinic deficiency (folate, vitamin b, iron), stopping smoking, stress, menstruation, trauma, food allergies or hypersensitivity to sodium lauryl sulphate (found in many brands of toothpaste). aphthous stomatitis has no clinically detectable signs or symptoms outside the mouth, but the recurrent ulceration can cause much discomfort to those affected. treatment is aimed at reducing the pain and swelling and speeding healing, and may involve systemic or topical steroids, analgesics (pain killers), antiseptics, anti-inflammatories or barrier pastes to protect the raw area(s). infection infectious causes of oral ulceration agentexample(s) viralchickenpox, hand, foot and mouth disease, herpangina, herpetic stomatitis, human immunodeficiency virus, infectious mononucleosis bacterialacute necrotizing ulcerative gingivitis, gangrenous stomatitis, syphilis, tuberculosis fungalblastomycosis, cryptococcosis, histoplasmosis, paracoccidioidomycosis parasiticleishmaniasis many infections can cause oral ulceration (see table). the most common are herpes simplex virus (herpes labialis, primary herpetic gingivostomatitis), varicella zoster (chicken pox, shingles), and coxsackie a virus (hand, foot and mouth disease). human immunodeficiency virus (hiv) creates immunodeficiencies which allow opportunistic infections or neoplasms to proliferate. bacterial processes leading to ulceration can be caused by mycobacterium tuberculosis (tuberculosis) and treponema pallidum (syphilis). opportunistic activity by combinations of otherwise normal bacterial flora, such as aerobic streptococci, neisseria, actinomyces, spirochetes, and bacteroides species can prolong the ulcerative process. fungal causes include coccidioides immitis (valley fever), cryptococcus neoformans (cryptococcosis), and blastomyces dermatitidis ("north american blastomycosis"). entamoeba histolytica, a parasitic protozoan, is sometimes known to cause mouth ulcers through formation of cysts. epstein-barr virus-positive mucocutaneous ulcer is a rare form of the epstein-barr virus-associated lymphoproliferative diseases in which infiltrating, epstein-barr virus (i.e. ebv)-infected b cells cause solitary, well-circumscribed ulcers in mucous membranes and skin. drug-induced many drugs can cause mouth ulcers as a side effect. common examples are alendronate (a bisphosphonate, commonly prescribed for osteoporosis), cytotoxic drugs (e.g. methotrexate, i.e. chemotherapy), non-steroidal anti-inflammatory drugs, nicorandil (may be prescribed for angina) and propylthiouracil (e.g. used for hyperthyroidism). some recreational drugs can cause ulceration, e.g. cocaine. malignancy advanced oral cancer (t4 n2 m0, stage 4). note rolled margins of central ulcer and surrounding areas of premalignant change. the patient died two months after subsequent partial glossectomy (removal of part of the tongue) main article: oral cancer rarely, a persistent, non-healing mouth ulcer may be a cancerous lesion. malignancies in the mouth are usually carcinomas, but lymphomas, sarcomas and others may also be possible. either the tumor arises in the mouth, or it may grow to involve the mouth, e.g. from the maxillary sinus, salivary glands, nasal cavity or peri-oral skin. the most common type of oral cancer is squamous cell carcinoma. the main risk factors are long-term smoking and alcohol consumption (particularly when combined) and betel use. common sites of oral cancer are the lower lip, the floor of the mouth, and the sides, underside of the tongue and mandibular alveolar ridge, but it is possible to have a tumor anywhere in the mouth. appearances vary greatly, but a typical malignant ulcer would be a persistent, expanding lesion that is totally red (erythroplasia) or speckled red and white (erythroleukoplakia). malignant lesions also typically feel indurated (hardened) and attached to adjacent structures, with "rolled" margins or a punched out appearance and bleeds easily on gentle manipulation. if someone has an unexplained mouth ulcer persisting for more than 3 weeks this may indicate a need for a referral from the gdp or gp to hospital to exclude oral cancer. vesiculobullous diseases main article: vesiculobullous disease some of the viral infections mentioned above are also classified as vesiculobullous diseases. other example vesiculobullous diseases include pemphigus vulgaris, mucous membrane pemphigoid, bullous pemphigoid, dermatitis herpetiformis, linear iga disease, and epidermolysis bullosa.: 1, 22 allergy main article: stomatitis § allergic contact stomatitis rarely, allergic reactions of the mouth and lips may manifest as erosions; however, such reactions usually do not produce frank ulceration. an example of one common allergen is balsam of peru. if individuals allergic to this substance have oral exposure they may experience stomatitis and cheilitis (inflammation, rash, or painful erosion of the lips, oropharyngeal mucosa, or angles of their mouth). balsam of peru is used in foods and drinks for flavoring, in perfumes and toiletries for fragrance, and in medicine and pharmaceutical items for healing properties. other causes a wide range of other diseases may cause mouth ulcers. hematological causes include anemia, hematinic deficiencies, neutropenia, hypereosinophilic syndrome, leukemia, myelodysplastic syndromes, other white cell dyscrasias, and gammopathies. gastrointestinal causes include celiac disease, crohn's disease (orofacial granulomatosis), and ulcerative colitis. dermatological causes include chronic ulcerative stomatitis, erythema multiforme (stevens-johnson syndrome), angina bullosa haemorrhagica and lichen planus. other examples of systemic disease capable of causing mouth ulcers include lupus erythematosus, sweet syndrome, reactive arthritis, behçet syndrome, granulomatosis with polyangiitis, periarteritis nodosa, giant cell arteritis, diabetes, glucagonoma, sarcoidosis and periodic fever, aphthous stomatitis, pharyngitis and adenitis. the conditions eosinophilic ulcer and necrotizing sialometaplasia may present as oral ulceration. macroglossia, an abnormally large tongue, can be associated with ulceration if the tongue protrudes constantly from the mouth. caliber persistent artery describes a common vascular anomaly where a main arterial branch extends into superficial submucosal tissues without a reduction of diameter. this commonly occurs in elderly people on the lip and may be associated with ulceration. treatment treatment is cause-related, but also symptomatic if the underlying cause is unknown or not correctable. it is also important to note that most ulcers will heal completely without any intervention. treatment can range from: smoothing or removing a local cause of trauma addressing dry mouth substituting a problem medication or switching to sls-free toothpaste maintaining good oral hygiene and use of an antiseptic mouthwash or spray (e.g. chlorhexidine), which can prevent secondary infection and therefore hasten healing a topical analgesic (e.g. benzydamine mouthwash) to reduce pain topical (gels, creams or inhalers) or systemic steroids may be used to reduce inflammation an antifungal drug may be used to prevent oral candidiasis developing in those who use prolonged steroids people with mouth ulcers may prefer to avoid hot or spicy foods, which can increase the pain self-inflicted ulceration can be difficult to manage, and psychiatric input may be required in some people: 53 for recurrent ulcers, vitamin b12 has been shown to be effective epidemiology oral ulceration is a common reason for people to seek medical or dental advice.: 52 a breach of the oral mucosa probably affects most people at various times during life. for a discussion of the epidemiology of aphthous stomatitis, see the epidemiology of aphthous stomatitis.