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FACT SHEET: Tuberculosis (also known as TB; caused by Mycobacterium tuberculosis complex bacilli bacteria which attack the lungs in about 70% of cases, but can attack any part of the body)

Date of Publication: March 11, 2013

Is the initiation of non-invasive dental hygiene procedures* contra-indicated?

  • Potentially; this depends whether the patient/client has TB infection (formerly referred to as latent TB infection [LTBI], which is not contagious to others and therefore there is no contraindication) OR the patient/client has TB disease (formerly referred to as active TB disease) of the lungs, respiratory tract, or oral cavity (in which cases there is a contraindication until the patient/client is treated and becomes non-infectious).1
  • In cases of active pulmonary (lung) or respiratory tract tuberculosis (which pose contagious risk by airborne spread to others, particularly when the patient/client has a cough) or active oral tuberculosis (which is rare, but which poses a small risk of direct transmission), deferral is indicated until the patient/client is no longer contagious to others nor has oral lesions which interfere with non-invasive procedures.
  • A positive tuberculin skin test (TST) does not necessarily indicate TB disease (particularly if the test was performed as part of a routine screening process in an asymptomatic individual, rather than for diagnostic or contact investigation purposes). If the tuberculin positive patient/client has no signs or symptoms of TB coupled with a negative chest X-ray, the patient/client likely has TB infection, rather than TB disease. TB infection is not a contraindication to non-invasive or invasive dental hygiene procedures.

Is medical consult advised?  

  • Yes. Persons suspected of having TB infection or disease should be referred to a physician for work-up, which may include a medical history, physical examination, test for TB infection (tuberculin skin test2 or TB blood test3), chest X-ray, sputum collection4, and other tests as appropriate. A medical consult is particularly urgent where active pulmonary TB disease is suspected (see below) given the infectious risk to others. Depending on their risk status, persons diagnosed with TB infection may be prescribed a prophylactic anti-tuberculous antibiotic (e.g., rifampin [RMP] daily for 4 months, or isoniazid [INH] + rifapentine weekly for 3 months) to reduce the likelihood of future conversion from latent infection to active disease.5 Persons diagnosed with active pulmonary TB are usually treated with several anti-tuberculosis medications for 4 to 9 months and are closely monitored. Drug resistance is a growing concern in many countries, although a lesser concern in Canada.

Is the initiation of invasive dental hygiene procedures contra-indicated?**

  • Yes, for tuberculosis disease (as per Ontario Regulation 501/07 made under the Dental Hygiene Act, 1991). 

Is medical consult advised? 

  • Yes, see above.

Is medical clearance required? 

  • Yes − specifically for tuberculosis disease in patients/clients. Furthermore, if you, the dental hygienist, have been diagnosed with, and treated for, TB disease, you should receive medical clearance before returning to work.

Is antibiotic prophylaxis required?  

  • No (pertaining to prophylaxis for invasive dental procedures, as distinct from chemoprophylaxis [i.e., preventive treatment] for TB infection). 

Is postponing treatment advised?

  • Yes, if patient/client has active pulmonary/respiratory/oral TB; see above. Elective dental treatment should be deferred until the patient/client has been declared non-contagious by a physician. Urgent dental care for a person with suspected or active tuberculosis disease should be provided in a facility that has the capacity for isolation from airborne infection and a respiratory protection program in place; this includes use of appropriate respiratory protection, such as fitted N-95 respirators.6

Oral management implications

  • Mode of transmission for active pulmonary or respiratory tract TB is airborne via droplet spread from one person to another via coughing, sneezing, speaking, shouting, singing, or blowing out air. The tubercle bacilli may be inhaled by others and cause infection.7 TB disease is most contagious when TB bacilli are found in a person’s sputum (phlegm). Only persons with TB disease (as opposed to those with TB infection) can transmit the disease, and these persons generally have signs/symptoms. Once a person is infected with M. tuberculosis, the incubation period until demonstrable primary lesion or significant TST reaction and positivity of IGRA is typically 2–10 weeks. An infected person can develop TB disease within weeks of exposure or months to years later or never (see below).
  • A patient/client with TB infection (which is non-infectious to others) may be treated in the dental/dental hygiene office under standard infection control precautions. A person with a “positive”8 tuberculin skin test and no signs/symptoms/proof of active disease is not contagious to others and cannot transmit TB.
  • The transmission of TB in healthcare settings to both patients/clients and healthcare workers has been documented. If you think you have been exposed to someone with TB disease, contact your physician or nurse practitioner.
  • When entering a room where it is known that a patient/client has untreated or incompletely treated pulmonary TB, healthcare professionals should wear personal respiratory protective devices capable of filtering submicron particles (fitted N-95 respirator). Standard precautions are insufficient to prevent transmission of Mycobacterium tuberculosis, and ordinary surgical/procedure masks are not designed to protect against airborne transmission of M. tuberculosis.
  • If a patient/client with signs/symptoms suggest of TB disease presents to the dental hygiene office, that person should be promptly removed from the vicinity of other patients/clients or staff and be instructed to wear a surgical/procedure mask and immediately referred for medical care. 
  • Effective antimicrobial therapy for active pulmonary TB usually eliminates communicability within 2 to 4 weeks, although M. tuberculosis may be still cultured from sputum.9
  • In the case of oral TB disease (see below), it is possible, but unlikely, for oral health professionals to contract infection through contact with living tubercle bacilli. Direct invasion through mucous membranes or breaks in the skin may rarely occur.
  • Various anti-tuberculosis drugs should prompt careful choice of analgesics. For patients/clients taking isoniazid, acetaminophen should be avoided (due to hepatotoxicity). Aspirin (ASA) should avoided in patients/clients taking streptomycin or amikacin (due to kidney toxicity).10 
  • While a tuberculosis vaccine (BCG) exists, it is not widely used in Canada and the USA (beyond select populations at elevated risk, such as certain First Nations and Inuit populations) given the relatively low prevalence of TB in these countries, as well as issues associated with the vaccine itself. Thus, BCG immunization is not generally considered a preventive measure for Ontario healthcare workers, but may be considered on an individual basis in at-risk settings.
  • In most cases, a two-step baseline tuberculin skin test is recommended for all healthcare workers in all healthcare settings (as per the 2022 Canadian Tuberculosis Standards).11 A two-step baseline TST is particularly important for healthcare workers who may undergo tuberculin skin tests at regular intervals.12
  • In Ontario, tuberculosis is a specified Reportable Communicable Disease (as per Ontario Reg 559/91 and amendments under the Health Protection and Promotion Act). Thus, physicians and laboratories (and other specified parties) are obligated to report this disease to the local Medical Officer of Health so the local public health unit can ensure affected persons are appropriately treated and contact tracing occurs to minimize further disease transmission.13

Oral manifestations

  • While TB disease usually affects the lungs, TB bacilli can spread hematogenously (i.e., via the blood) to other parts of the body, including bones such as the mandible and maxilla. Tuberculous osteomyelitis can result from bony involvement of the mandible or maxilla. 
  • While uncommon (0.05% to 5% of all infections), tuberculous lesions of the oral cavity do occur. Lesions of the oral mucosa are usually secondary to pulmonary disease, whether via hematogenous spread or via sputum-borne organisms entering mucosal tissue through small breaks in the surface.
  • While lesions may occur at any site on the oral mucous membrane, the tongue is most commonly affected, followed by the palate, lips, buccal mucosa, gingiva and frenula. The tonsils, uvula, and salivary glands may also be affected. The typical tuberculous lesion is a chronic, indurated, irregular, superficial or deep, painless or painful, nonhealing ulcer, which tends to increase slowly in size. The ulcers may be singular or multiple. More rarely, mucosal lesions show swelling or fissuring without obvious ulceration. Tuberculous gingivitis is another unusual manifestation of TB. 
  • Pharyngeal involvement results in painful ulcers, which may cause dysphagia, odynophagia (painful swallowing), and voice changes. 
  • When oral tuberculosis arises as a primary lesion14, an ulcer is the most common presentation, often developing along the lateral margins of the tongue (that rub against rough, sharp, or broken teeth) or at sites of other soft tissue inflammation. The gingiva, mucobuccal fold, and extraction sites are other typical sites. As well, cervical lymph nodes may be palpable. Patients/clients with oral tubercular lesions often have a history of preexisting trauma, and persons with primary lesions tend to be younger than those with secondary lesions.
  • Involvement of the submandibular and cervical nodes (usually as a result of ingesting the microbe in non-pasteurized milk) causes enlargement of these nodes. This is called scrofula (tuberculous lymphadenitis). 
  • Of the various anti-tuberculosis drugs, rifampin in particular can cause oral manifestations, such as increasing incidence of infection, delayed healing, and gingival bleeding. Rifampin can also result in temporary discolouration (yellow, reddish-orange, or brown colour) of saliva and teeth.15
  • Anti-tuberculosis drug rifapentine can cause ulcers, sores, and white spots in the mouth, and less commonly can cause gingival (as well as other unusual) bleeding.

Related signs and symptoms

  • Tuberculosis is an infectious, chronic granulomatous disease, now classified as TB infection or TB disease (i.e., active — pulmonary and/or extrapulmonary).  
  • About one-quarter of the world’s human population is infected with TB, mostly in less-developed countries. In 2019, an estimated 10 million people worldwide fell ill with tuberculosis, and 1.4 million people died from TB.  
  • Canada has one of the world’s lowest rates of active tuberculosis, with 1,829 cases reported in 2021. Of these cases, about 77% were foreign-born, 17% were Canadian-born Indigenous, and 4% were Canadian-born non-Indigenous. In Ontario in 2022, 751 cases were reported, along with 47 deaths.
  • Symptoms of TB disease include: 
    • a bad cough that lasts 2–3 weeks or longer;
    • chest discomfort;
    • coughing up blood or sputum;
    • general weakness;
    • fatigue;
    • unintentional weight loss;
    • decreased appetite;
    • chills;
    • fever; and
    • night sweats.
  • In addition to the lungs, tuberculosis may affect any organ or tissue, including the lymph nodes, pleura, pericardium, kidneys, bones and joints, larynx, middle ear, intestines, peritoneum, eyes, brain, and spinal cord. Disseminated, or miliary, TB involves the whole body. 
  • If not treated properly, TB disease can be fatal. 
  • Certain population groups in Canada have an increased risk of TB infection and disease, including:
    • people who have come into close contact with individuals with known or suspected TB (e.g., family members or people sharing living spaces);
    • people with a history of TB disease who received inadequate treatment;
    • people living in communities with high rates of TB infection or disease (e.g., many First Nations and Inuit communities and immigrant and refugee populations from endemic countries in Asia, Africa, Latin America, the Caribbean, Eastern Europe, and Russia);
    • the poor, especially the urban homeless; 
    • residents of long-term care and correctional facilities; and
    • persons who work with any of the above groups (e.g., healthcare workers and correctional services staff).
  • While most people who have TB infection never go on to develop TB disease (5% to 10% lifetime risk in those infected)16, persons at elevated risk for the development of TB disease (including reactivation of the primary lesion which was previously walled off) include:
    • persons who became infected with TB bacteria in the last 2 years;
    • persons with HIV infection;
    • persons with other health problems that compromise the body’s ability to fight infection (e.g., diabetes, chronic kidney failure, or head and neck cancer);
    • babies and young children;
    • persons being treated with immunosuppressive drugs;
    • persons who abuse alcohol or use illegal drugs;
    • elderly people;
    • persons who were inadequately treated for TB in the past; and
    • persons with a chest X-ray showing signs of old TB.
  • Post-TB lung disease is a term that comprises diverse chronic lung disease and respiratory pathologies experienced by TB patients/clients after treatment for TB disease. Survivors have high rates of airway disease, including chronic obstructive pulmonary disease (COPD), bronchiectasis17, and airway stenosis, and they also experience higher rates of restrictive lung disease.
  • With regard to non-respiratory disease post-TB, survivors experience higher rates of cardiovascular disease, malignancy, mood disorders, smoking, and alcohol use disorder, in addition to infectious and immunosuppressive comorbidities placing persons at risk of TB.

References and sources of more detailed information

Date: January 28, 2013
Revised: May 10, 2020; April 14, 2024


1 The 2022 Canadian Tuberculosis Standards (8th edition) replaced the long-standing terms “active TB disease” and “latent TB infection (LTBI)” with “TB disease” and “TB infection” respectively.
2 A tuberculin skin test is also referred to as a Mantoux or PPD (purified protein derivative) test.
3 TB blood test = interferon gamma release assay (IGRA)
4 Two to three sputum samples are typically submitted for TB smear, PCR (polymerase chain reaction) test, and culture.
5 In 2019, the Centers for Disease Control and Prevention changed its previous recommendations to encourage treatment for all U.S. healthcare personnel with untreated LTBI, unless treatment is contraindicated. In the Canadian context, LTBI treatment is now referred to as tuberculosis preventive treatment (TPT).
6 Until a patient/client diagnosed with TB disease has been rendered non-contagious (see Footnote 9), the use of ultrasonic scalers or air polishers or anything else that may generate an aerosol is generally contraindicated.
7 Exposure risk depends on the concentration of droplet nuclei in the air and duration of exposure to a person with pulmonary/respiratory tract TB disease.
8 A “positive” TST is defined as a certain number of millimetres of induration (hardness) in the transverse diameter on the forearm, according to certain risk criteria.
9 According to the Centers for Disease Control and Prevention, in healthcare settings patients/clients can be considered non-contagious to others when they meet all of the following three criteria:

  • they have three consecutive negative acid-fast bacilli (AFB) sputum smears collected in 8- to 24-hour intervals (one should be an early morning specimen);
  • they are compliant with an adequate treatment regimen for two weeks or longer; and
  • their symptoms have improved clinically (for example, they are coughing less and they no longer have a fever).

10 Streptomycin (an older anti-TB drug with antibiotic resistance issues) and amikacin (which has significant draw-backs, including potential hearing loss) are not considered standard drugs for treatment of TB disease in Canada.
11 A baseline two-step tuberculin skin test should be done unless there is documentation of a prior negative two-step test, in which case a single-step test should be done. Tuberculin skin testing involves intradermal injection of an antigen called purified protein derivative (PPD).
12 In 2019, the Centers for Disease Control and Prevention (U.S.) changed its previous recommendations to state that no routine serial TB testing is recommended at any interval for U.S. healthcare personnel after baseline in the absence of a known exposure or ongoing transmission. In 2022, the Canadian Tuberculosis Standards from the Canadian Thoracic Society stated that recommendations for periodic and serial (repeated) tuberculin skin testing for healthcare workers vary with the setting, but periodic (repeated) testing is no longer routinely recommended for all healthcare workers.
13 It is also a requirement for Ontario-licensed dentists to report a suspected or confirmed case of a reportable communicable disease (including tuberculosis) to their local medical officer of health.
14 While the mechanism of primary inoculation is uncertain, it is likely that M. tuberculosis is inoculated directly into the oral mucosa.
15 Rifampin can also cause temporary discolouration of skin, urine, stool, sweat, and tears.
16 The development of TB disease occurs with greatest frequency in the first 2 years after infection. 50% of the total lifetime risk is estimated to occur in this period. TB infection can persist for a lifetime.
17 Bronchiectasis is characterized by enlargement and “pocketing” of the bronchi/bronchial tubes, in which mucus collects and bacteria breed, thereby leading to recurrent lung infections and cumulative damage to the airways.

* Includes oral hygiene instruction, fitting a mouth guard, taking an impression, etc.
** Ontario Regulation 501/07 made under the Dental Hygiene Act, 1991. Invasive dental hygiene procedures are scaling teeth and root planing, including curetting surrounding tissue.