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FACT SHEET: Substance Use Disorder (also known as “SUD”, “drug use disorder”, and “substance-related disorder”1; includes “drug or alcohol dependency” [also known as “drug addiction or alcoholism”, “chemical dependence”, and “chemical dependency”], “drug or alcohol misuse” [also known as “substance misuse”]2, and “drug or alcohol abuse” [also known as “substance abuse”])

Date of Publication: June 20, 2019

Note: Cannabis is addressed in more detail in the dedicated Cannabis Fact Sheet.

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

  • No, unless:
    • the patient/client displays behavioural signs/symptoms that pose a risk to himself/herself or the dental hygienist during procedures (e.g., extreme restlessness or aggression); or
    • the patient/client is intoxicated or “high” and therefore is incapable of giving informed consent.

Is medical consult advised?  

  • Yes, if undiagnosed substance use disorder (misuse or dependence) is suspected. The patient/client’s primary physician may be able to assist with access to a treatment program or an addiction treatment specialist.
  • Yes, if poor response to substance misuse/dependence treatment is suspected.3

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

  • Yes, if drug or alcohol dependency is of a type or extent that may affect the appropriateness or safety of scaling and root planing, including curetting surrounding tissue (as per Ontario Regulation 501/107). 

Is medical consult advised? 

  • See above. Additionally, before aggressive nonsurgical (or surgical) periodontal therapy is undertaken, the patient/client’s physician should be consulted to confirm there is no immunosuppression or significant liver or kidney damage. Also, pain control should be coordinated with the primary care physician for patients/clients recovering from substance misuse/dependence. 

Is medical clearance required? 

  • Yes, if drug or alcohol dependency meets the proscribed initiation criteria of O. Reg. 510/107.   
  • Yes, if the patient/client has history of intravenous (IV) drug misuse.
  • Yes, if there is a bleeding disorder (e.g., caused by thrombocytopenia resulting from alcoholism or habitual cocaine use). 

Is antibiotic prophylaxis required?  

  • Possibly, if the patient/client has a history of intravenous drug misuse.4

Is postponing treatment advised?

  • Yes, in most circumstances where the patient/client has “self-medicated” with drugs of misuse or alcohol prior to the dental/dental hygiene appointment. If the patient/client is “high” or intoxicated, procedures should be deferred until the patient/client is not mentally impaired and not at undue risk of significant myocardial ischemia, cardiac arrhythmia, or other serious medical sequelae in the operatory (particularly with use of cocaine or methamphetamine). Patients/clients “high” on methamphetamine should not receive dental treatment for at least 8 hours (and ideally at least 24 hours) after last administration of the drug.  
  • Yes, if patient/client is medically unstable. An overdose of a misused substance requires immediate medical attention. Alcohol poisoning is a medical emergency. 
  • Yes, if the patient/client has untreated alcoholic liver disease. Elective, outpatient dental/dental hygiene care should be deferred pending assessment by a physician regarding bleeding risk, etc. 
  • Yes, until medical assessment has occurred regarding possible antibiotic prophylaxis in patients/clients with history of intravenous drug misuse.   
  • Yes, if the patient/client is unwilling or unable to comply with treatment. When recovery from addiction is further progressed, the patient/client may be more receptive to dental hygiene care.

Oral management implications

  • Patients/clients who are dependent on alcohol or drugs or who are receiving treatment for substance misuse pose complex issues for the dental hygienist related to preventive oral healthcare. In addition to poor self-care, there are numerous potential oral manifestations of substance abuse.
  • History-taking should include explicit questions about “recreational drugs” and “alcohol”, in addition to “prescribed medications”, “drugs”, and “over-the-counter medications”. Chemically dependent patients/clients should be identified to avoid interactions between drugs used in the dental office and abused substances.
  • Patients/clients with substance misuse issues typically seek dental care only when they are in severe pain. Furthermore, the oral health problem is often in an advanced state, because of neglect or because pain sensation has been blunted by the use of drugs. Chemically dependent patients/clients may also experience tolerance to analgesics and sedatives.
  • Red flags for suspicion of substance misuse in a patient/client include: frequently misses appointments; careless appearance and poor hygiene; lapses in concentration and/or memory; smell of substance on breath, body, or clothes; slurred speech; rapid mood swings; needle marks on arms; abnormal pupillary constriction or dilatation; wears sunglasses in operatory (to cover dilated or red pupils, red eyes, or blank stare); wears long clothes on a hot day (to cover needle marks); continually sniffs nose and uses tissues; hacking cough; tremors of hands or head; frequently requests specific medication for pain; and high tolerance to analgesics and sedatives. 
  • The dental hygienist should determine if the patient/client has “self-medicated” with alcohol or drugs prior to the dental/dental hygiene appointment. If so, then the care plan may need to be modified or cancelled to avoid any substance-associated behavioural problems, drug interactions (e.g., with local anaesthetics or nitrous oxide), or other safety issues. Drugs that depress brain activity ― such as opioids, benzodiazepines, and antihistamines ― can enhance the effects of local anaesthetics.
  • Because some drug-misusing patients/clients may seek dental/dental hygiene treatment to obtain prescriptions for misused substances, prescription pads should be kept out of sight and be inaccessible.
  • Multiple short appointments may be necessary to manage anxiety or emotional instability in drug-dependent patients/clients.
  • Blood pressure and pulse should be monitored during appointments for cocaine and methamphetamine misusers. Such patients/clients are at elevated risk for cardiac arrhythmias, myocardial infarction, and stroke
  • Malnutrition is common in substance misusers, and thus nutritional counselling and dietitian referral may be indicated.
  • Methamphetamine users tend to consume large amounts of soft drinks, which compounds the problems of “meth mouth”. The remaining dentition is often unsalvageable, with extractions being the only viable option.
  • Patients/clients who are in recovery programs may seek long-neglected oral healthcare as part of their recuperation efforts. However, recovering addicts may be very reluctant about taking any type of medication, thus complicating efforts to control pain during scaling and root debriding. Pain control should be coordinated with the primary physician.
  • If a chemically dependent patient/client requires sedation with nitrous oxide or benzodiazepines for dental treatment, he/she should be referred to practitioners experienced in treating such patients/clients. Persons with a significant substance misuse history and needing extensive dental treatment may require care in a hospital or operating room.
  • Opioid analgesics and other addictive substances should be avoided if possible in patients/clients with drug/alcohol misuse or dependence. If prescribed, the patient/client should be monitored to ensure proper medication use. A “pain contract” outlining specific pain management strategies may be indicated, and engagement of the patient/client’s primary physician in this process should be considered. In most circumstances, nonsteroidal anti-inflammatory drugs (NSAIDs) are recommended for post-procedure pain to avoid addiction issues posed by opioids. 
  • Epinephrine and other vasoconstrictors should be avoided for 24 hours after the last use of cocaine or methamphetamine.
  • Excessive bleeding may occur secondary to liver disease in alcoholism; lab tests may be needed for confirmation.
  • Complex oral procedures should only be performed when the patient/client is in a stable condition in the context of the substance use disorder.
  • Realistic goals for oral self-care should be set for both active drug misusers and recovering addicts. A daily fluoride rinse regimen is often appropriate, particularly if the patient/client has a moderate to high caries risk. Fluoride therapy is important for heroin addicts enrolled in a methadone program, because daily methadone is typically administered in a sugary syrup.
  • Fluoride and antimicrobial rinses recommended to patients/clients with alcoholism should be nonalcoholic in composition to avoid contributing to their addiction. Furthermore, even tiny amounts of alcohol ingested by a patient/client taking alcohol-sensitizing drugs (e.g., disulfiram) can cause severe gastrointestinal distress and hypotension. 

Oral manifestations

  • Substance misuse may result in xerostomia, increased caries rate, enamel erosion, periodontal disease, and impaired tissue healing.
  • Tremors of the tongue can occur during alcohol withdrawal.
  • Localized tissue necrosis may result from placement of drugs directly in the vestibule or sublingually. In particular, gingival lesions and recession may result from cocaine placement, as may dental erosion (particularly of the facial aspects of the maxillary teeth from persistent rubbing of powder over these surfaces). 
  • Buccal cervical caries can result from ingestion of large quantities of sweets and carbohydrates, as often craved by alcohol and drug misusers.
  • Oral candidiasis can result from immunosuppression and/or nutritional deficiencies. 
  • Glossodynia can result from malnutrition and immunosuppression.
  • Bruxism often occurs in persons using cocaine or methamphetamine, resulting in flat cuspal planes on the molars and premolars.
  • Bruxism and jaw clenching occur with MDMA5 (“ecstasy”) use (for which some “ravers” use pacifiers).
  • Angular cheilitis, glossitis, and loss of tongue papillae can result from nutritional deficiencies in patients/clients with chronic alcoholism. Furthermore, spontaneous gingival bleeding and mucosal ecchymoses and petechiae can result from vitamin K deficiency, impaired hemostasis, portal hypertension and splenomegaly (causing thrombocytopenia). A musty, sweet odour to the breath is associated with liver failure, as is jaundice of the mucosal tissue.
  • Sialadenosis6 is a common finding in patients/clients with cirrhosis of the liver, which can result from alcoholism. 
  • Risk of oral squamous cell carcinoma is elevated with long-term alcohol use (potentiated by smoking tobacco) or chronic smoking of cannabis. High-risk sites include the lateral border of the tongue and the floor of the mouth. 
  • “Meth mouth” results from smoking acidic methamphetamine. It is characterized by rampant caries, xerostomia, gingival inflammation, advanced periodontal disease, and poor oral hygiene. In methamphetamine-induced caries, damage begins at the gingiva with attack on the buccal smooth surfaces of posterior teeth and the interproximal spaces of anterior teeth, progressing to destruction of the coronal tooth structure. Vomiting also contributes to rampant caries and dental erosion in meth misusers. 
  • Halitosis occurs with long-term use of anabolic steroids.
  • Methadone treatment for opioid addiction can adversely affect oral health due to the high sugar content and acidity of the syrup. Complications include caries, erosion, and xerostomia.

Related signs and symptoms

  • Substance use disorder7 is a significant problem in Canada, involving legal (e.g., alcohol and cannabis) and prescribed psychoactive substances (e.g., certain opioids) as well as illegal psychoactive substances. More than 19% of Canadians aged 12 and older (or about 5.8 million people) are considered heavy drinkers8, with males more likely to report heavy alcohol use than females. As well, opioid addiction (often involving prescription narcotics) is an increasingly recognized area of concern in Ontario and Canada.
  • Substance misuse is a pattern of self-administered drug use that may lead to drug addiction and psychologic and physiologic dependence.9 Routes of administration vary amongst substances of misuse, and they include oral ingestion, injection (intravenous, intramuscular, or subcutaneous), snorting, inhalation, smoking, and rectal administration.
  • Denial is often an integral part of substance use disorder, which is an impediment to treatment and recovery and a precipitating factor for relapse.
  • Drug misuse occurs at elevated rates in dental office personnel compared with the general population due to ready access to opioid analgesics, sedative-hypnotic drugs, and nitrous oxide. 
  • A person who has developed physiologic drug dependence will go through drug withdrawal upon cessation of drug use. Withdrawal signs/symptoms may include sweating, anxiety, vomiting, diarrhea, cramps, high blood pressure, headaches, and seizures.
  • Drugs that are often misused include the following10:


Drug Drug Effects and Health Consequences
Alcohol Short-term use: reduced inhibitions; decreased anxiety; slowed reactions; slurred speech; impaired decision-making; unconsciousness

Long-term use: liver damage (including hepatitis and cirrhosis); increased risk of oral, breast, colorectal, and stomach cancers; heart failure; dementia

Depressants (including barbiturates [“downers”], benzodiazepines, and flunitrazepam) Lowered inhibitions; slowed pulse and breathing; lowered blood pressure; poor concentration; confusion; impaired memory, judgement, and coordination; slurred speech; dizziness
Opioids (including codeine, morphine, fentanyl, carfentanil, oxycodone, hydrocodone, hydromorphone, meperidine, and heroin) Euphoria; drowsiness; respiratory depression; nausea; constipation; confusion; sedation; unconsciousness
Anabolic steroids Short-term use: enhanced athletic performance; increased muscle mass; aggression; weight gain

Long-term use: shrinkage of testicles; breast development (in males); cessation of menses; facial hair (in females); acne; depression and mood swings; hypertension; liver damage; increased risk of injury to muscles, tendons, and ligaments

amphetamines (“uppers”) Feelings of exhilaration and energy; increased heart rate, blood pressure, and metabolism; irregular heart rhythm; reduced appetite; weight loss; heart failure
cocaine (“coke” or “crack”) Similar effects to amphetamines; increased temperature; chest pain; respiratory failure; stroke; seizures; malnutrition
methamphetamine (“meth”) Similar effects to amphetamines; aggression; psychotic behaviour; memory loss; impaired memory and learning; cardiac and neurologic damage; sensation of bugs crawling under the skin
methylphenidate Similar effects to amphetamines; increased or decreased blood pressure; psychosis; digestive problems
cannabinoids (including cannabis [marijuana], hashish, and sinsemilla) Short-term use: relaxation; euphoria; confusion; poor coordination; bloodshot eyes; hunger; difficulty with concentration, learning, and memory and problem-solving; sensory distortions; dilated pupils; tachycardia; bronchial hyperactivity

Long-term use: elevated risk of chronic obstructive pulmonary disease and lung cancer (when smoked); chronic use can result in withdrawal symptoms

lysergic acid (LSD) Short-term use: hallucinations; sensory distortions; extreme emotions from panic to euphoria; increased blood pressure and heart rate; hyperthermia; acute anxiety

Long-term use: paranoia; delusions of grandeur; depression; psychosis; flashbacks

mescaline (“buttons” or peyote) Hallucinations; hyperthermia; increased blood pressure; sweating; impulsive behaviour; rapid shifts in emotion
volatile solvents (including airplane glue, rubber cement, spray paint, hair spray, paint thinner, spot remover, and gasoline) Short-term use: reduced inhibitions; excitement; euphoria; irritability; slurred speech; dizziness; drowsiness

Long-term use: confusion; delirium; emotional instability; impaired thinking; psychomotor impairment; damage to brain/nervous system, liver, kidney, lung, and bone marrow

Systemic effects: respiratory arrest; asphyxia; cardiac arrhythmia; suicide

volatile nitrites (including amyl nitrite and room deodorizers) Short-term use: relaxation of smooth muscles; altered consciousness; enhanced sexual pleasure

Long-term use: headaches; dizziness; giddiness; shock; loss of consciousness; nitrite poisoning; damage to nervous system; impaired perception, reasoning, and memory; altered muscular coordination

anaesthetics (nitrous oxide) Short-term use: euphoria; giddiness

Long-term use: addiction; frostbite of nose and vocal cords from direct inhalation from pressured tank; peripheral nerve damage; brain damage due to oxygen deprivation

Dissociative Drugs
phencyclidine (PCP or “angel dust”) Short-term use: reduced inhibitions; sensory deprivation; reduced pain

Long-term use: combative behaviour; confusion, paranoia, and agitation; inability to speak; amnesia

Systemic effects: severe hypertension; respiratory depression; catatonia; seizures; coma; flashbacks11

ketamine Elevated blood pressure and heart rate; memory loss; nausea and vomiting; impaired motor function; delirium; depression ; respiratory depression and arrest
Club Drugs
MDMA (3,4-methyl​enedioxymethamphetamine or “ecstasy”) Mild hallucinogenic effects; increased tactile sensitivity; reduced inhibitions; anxiety; sweating; muscle cramping; impaired memory; hyperthermia; depression
GHB (gamma-hydroxybutyrate) Drowsiness; nausea; headache; disorientation; decreased coordination; memory loss; unconsciousness; seizures
flunitrazepam (Rohypnol®) Sedation; muscle relaxation; confusion; memory loss; dizziness; impaired coordination


  • Agitation or extreme depression may indicate a drug overdose.
  • A variety of cutaneous lesions may indicate parenteral drug abuse. These include skin “tracks” (chronic inflammation from repeated injections)12, cellulitis, and thrombophlebitis. Subcutaneous abscesses can result from “popping” of heroin.
  • Burns and scars on the thumb of the dominant hand may result from repeated use of a disposable lighter for smoking crack cocaine. 
  • Nosebleeds and significant nasal damage can result from snorting or inhaling drugs. 
  • Tremors of the hands and eyelids may be signs of alcohol withdrawal.
  • Extraoral facial signs of alcohol misuse include:
    • red facial skin and spider angiomas (from dilated blood vessels) on the nose;
    • yellow facial skin from jaundice caused by liver disease;
    • red or swollen eyes; and
    • angular cheilitis caused by vitamin B deficiency.
  • Nausea, vomiting, abdominal pain, and hypotension result if alcohol is ingested while a person is being treated with an alcohol sensitizing agent.
  • Infections with human immunodeficiency virus (HIV), hepatitis B, hepatitis C, and hepatitis D occur at elevated rates in patients/clients with a history of intravenous drug use.
  • Lung disease (including chronic obstructive pulmonary disease [COPD] and lung cancer) can result from misuse of inhaled or smoked drugs.
  • Long-term alcohol misuse can cause liver, kidney, heart, pancreas, brain, and reproductive system damage, in addition to affecting motor coordination. Malnutrition associated with alcoholism can lead to anemia due to dietary deficiencies in vitamin B12 and folic acid. Alcoholic liver disease can lead to bleeding tendencies, unpredictable metabolism of certain drugs, and risk for spread of infection. Alcoholic cirrhosis may be accompanied by ascites13, ankle edema, jaundice, and hemorrhage from esophageal varices. Consumption of alcohol during pregnancy can lead to fetal alcohol spectrum disorder.
  • Schizophrenia can be triggered by cannabis use in adolescents.
  • Drug and alcohol misuse can lead to homelessness, crime, unemployment, impaired driving, violence, stress, and child abuse.

References and sources of more detailed information

Date: December 2, 2018
Revised: April 5, 2023


1 “Substance-related disorder” also encompasses “substance-induced disorders” including intoxication, withdrawal, and other substance/medication-induced mental disorders. These conditions are also addressed to some degree in this fact sheet.
2 “Substance misuse” is a term that is roughly equivalent to “substance abuse”. However, “substance abuse” is increasingly being avoided by healthcare professionals due to its negative connotation.
3 Behavioural and pharmacologic treatments are used to treat drug or alcohol addiction. Medications used to treat depression and anxiety disorders are also used to treat patients/clients with addictive behaviour disorders. For alcoholism, alcohol sensitizing agents (e.g., disulfiram and citrated calcium carbamide), anti-craving agents (such as naltrexone), and antiemetic agents (such as ondansetron) may be employed. For patients/clients with addiction to heroin or narcotic painkillers, methadone (an opioid agonist) or buprenorphine (a partial opioid agonist/antagonist) can be used. Naloxone is an opioid antagonist used to block or reverse the effects of opioids, particularly for opioid overdoses.
4 Many IV drug users develop venous thrombosis and organic valvular heart disease. In particular, damage to the tricuspid valve is often associated with IV substance misuse. As well, IV drug use can result in endocarditis caused by Staphylococcus aureus on nonsterile needles.
5 MDMA = 3,4-methyl​enedioxymethamphetamine
6 Sialadenosis is bilateral, painless hypertrophy of the parotid glands.
7 In contradistinction to the fourth edition of the Diagnostic and Statistical Manual of Mental Disorders (DSM-4, published in 1994), DSM-5 (published in 2013) combines the DSM-4 categories of substance abuse and substance dependence into “substance use disorder” measured on a continuum from mild to severe.
8 In this context, heavy drinking refers to males who report having 5 or more drinks, or women who report having 4 or more drinks, on one occasion at least once a month in the past year. However, in 2023, the Canadian Centre on Substance Use and Addiction (CCSA) — in work funded by Health Canada — issued Canada’s Guidance on Alcohol and Health, which replaced Canada’s Low-Risk Drinking Guidelines of 2011. The 2023 evidence-based guidance document revised the concept of “safe drinking” downwards. The CCSA document noted that consumption of more than 2 standard drinks per occasion is associated with increased risk of harms to self and others, including injuries and violence. Furthermore, the 2023 CCSA document stated that there is a continuum of risk associated with weekly alcohol use. Consumption of more than 2 standard drinks per week elevates risk of several types of cancer (including colon and breast). At 7 standard drinks or more per week, risk of heart disease or stroke increases significantly. Each additional standard weekly drink greatly increases the risk of alcohol-related consequences.
9 Drug addiction is a compulsive and chronic need to use drugs despite causing physical harm to the user. Psychologic dependence relates to the user’s belief that the drug is needed to maintain a state of well-being. Physiologic dependence results from biologic alteration of the user’s brain from continual drug use, and drug tolerance ensues whereby increasingly large doses are required to produce the same effects obtained earlier with smaller doses. Withdrawal signs/symptoms occur upon abstinence from a habitually used substance.
10 Table modified from tables in 1/ Bowen DM (ed.) and Pieren JA (ed.). Darby and Walsh Dental Hygiene: Theory and Practice (5th edition). St. Louis: Elsevier; 2020 + 2/ Darby M (ed.) and Walsh M (ed.). Dental Hygiene: Theory and Practice (4th edition). St. Louis: Elsevier Saunders; 2015 + 3/ Little JW, Falace DA, Miller CS and Rhodus NL. Dental Management of the Medically Compromised Patient (9th edition). St. Louis: Elsevier; 2018.
11 PCP is retained in fat cells for several months after use, and it can be released during exercise, fasting, or in stressful situations.
12 Skin tracks typically appear as linear or bifurcated lesions, which become hyperpigmented and indurated.
13 Ascites is abnormal accumulation of fluid in the abdominal (i.e., peritoneal) cavity.

* 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.