Part I: Oral health implications
On any given day, a “big green gorilla” can show up at your practice. The impact of efforts to legalize medical and recreational marijuana (cannabis) has been enormous in the 21st century, and that certainly holds true for the dental profession.
A December, 2019 Marist Poll found that 62% of adults believe federal marijuana legalization is a “good idea.”1
But a report published by the American Dental Association, updated July 12, 2019 on cannabis oral health effects,6 raises some concerns for dentists:
Recent studies have tested the relationship between periodontitis and frequent cannabis use and adjusted for confounding factors such as cigarette smoking, alcohol use, social status and other health issues. 8, 46, 47 Significantly higher rates of periodontitis were observed among the frequent users compared to non-users, with significantly higher numbers of sites with high pocket depths (≥4mm) and attachment loss.6
Sales of legal cannabis in the U.S. amounted to nearly $10 billion in 2018 alone,2 up from $3.4 billion in 2014, with $12.8 billion estimated for 2019.3 Over 17,000 cannabis cultivators produced more than 2.5 million pounds of legal cannabis in 2018 alone.3
As of 2018, U.S. cannabis dispensaries accounted for $1.2 billion in sales compared to $624 million in other cannabis retail, and a very small amount from CBD pharmaceuticals.3 However, if the FDA approves hemp-based CBD as a food additive in general retail products, projected numbers would grow, and the market mix would shift to $5.3 billion for dispensaries, $12.6 billion for general retail and $2.2 billion from CBD pharmaceuticals by 2024.3
The global legal marijuana market size is expected to reach USD 73.6 billion by 2027, according to a new report published by Grand View Research, Inc.4
On the heels of the Agricultural Act of 2014 opening up pilot hemp-growing products, the Agricultural Improvement Act of 2018 moved the ball forward, allowing for legal commercial hemp cultivation. This paved the way for hemp-derived CBD products (containing less than 0.3% THC). But the guidelines are unclear and subject to various interpretations, and CBD edibles and supplements are still federally illegal. (One exception is Epidiolex, the first hemp-derived CBD drug to receive FDA approval (2018) as a treatment shown efficacious for mitigation of Dravet and Lennox-Gastaut syndromes.)
CBD consumers have cited pain relief, improving quality of life and treating or managing health problems as the main reasons for purchasing both hemp- and cannabis-derived products.
Ingestibles including food, confections and beverages, along with tinctures, will become the larger part of the CBD product profile.
To date, inhalables and sublinguals have been the biggest product categories in the cannabis market, but consumers are moving away from inhalables and vaping products. Ingestibles including food, confections and beverages, along with tinctures, will become the larger part of the CBD product profile. Prescription medications containing CBD will also grow as the FDA continues to approve more options. Wellness, beauty/skin products and vitamins are other significant product categories to watch.3
On the basis of type, the medical segment held the leading revenue share of 71.0% in 2019, owing to the growing adoption of cannabis as a pharmaceutical product for treating severe medical conditions, such as cancer, arthritis, and Parkinson’s disease and Alzheimer’s disease among other neurological conditions. Moreover, increasing need for pain management therapies along with growing disease burden of chronic pain among elders is expected to boost the product demand.3
With all of this activity and consumption, cannabis inhalation, ingestion and medication are having an ever-increasing impact on oral health.
According to the Australian Dental Journal,5
Cannabis abusers generally have poorer oral health than non-users, with an increased risk of dental caries and periodontal diseases. Cannabis smoke acts as a carcinogen and is associated with dysplastic changes and pre-malignant lesions within the oral mucosa. Users are also prone to oral infections, possibly due to the immunosuppressive effects. Dental treatment on patients intoxicated on cannabis can result in the patient experiencing acute anxiety, dysphoria and psychotic-like paranoiac thoughts. The use of local anesthetic containing epinephrine may seriously prolong tachycardia already induced by an acute dose of cannabis. Oral health care providers should be aware of the diverse adverse effects of cannabis on general and oral health and incorporate questions about patients’ patterns of use in the medical history.
The American Dental Association report, on cannabis oral health effects,6 provides valuable information for dentists. Some of the high points include:
- The use of cannabis, particularly marijuana smoking, has been associated with poor quality of oral health; etiology has been complicated by the number of associated factors with frequent users, including high tobacco, alcohol, and other drug use; poor oral hygiene practices; and infrequent visits to dentists.
- Cannabis use leads to xerostomia (dry mouth), which can contribute to a number of oral health conditions.
- The main psychotropic agent, THC, is an appetite stimulant, which often leads users to consume cariogenic snack foods.
- Regular cannabis users are known to have significantly higher numbers of caries than nonusers, particularly on normally easy-to-reach smooth surfaces.
- Leukoedema is more common among cannabis users than non-users but it is unclear whether associated irritants, such as orally inhaled smoke, rather than cannabis itself, may be contributing causes.
- Smoking marijuana is associated with gingival enlargement, erythroplakia and chronic inflammation of the oral mucosa with hyperkeratosis and leukoplakia, sometimes referred to as “cannabis stomatitis,” that can develop into malignant neoplasias.
- A synergistic effect between tobacco and cannabis smoke may increase oral and neck cancer risk for people who smoke both.
- The immunosuppressive effects of cannabis may contribute to a higher prevalence of oral candidiasis compared to non-users.
- Viable microbiota may be transmitted from contaminated marijuana, which could further exacerbate a pathogenic oral environment.
- A number of studies have suggested a direct relationship between cannabis use and periodontal disease.
- A currently intoxicated (i.e., “high”) user may present several difficulties for the dental practitioner. Increased anxiety, paranoia and hyperactivity may heighten the stress experience of a dental visit.
- Increased heart rate and other cardiorespiratory effects of cannabis make the use of epinephrine potentially life threatening.
In part two of this Incisor series on cannabis and dentistry, we will share best practice guidelines for assessing marijuana use—even for those unwilling to self-report—discuss dental findings that indicate marijuana use, and explore recommendations for dental healthcare providers treating users.
- Cannabis Intelligence Briefing, BDS Analytical. https://bdsa.com/wp-content/uploads/2019/03/BDS_pharmaceuticals_8.5x11_v3.pdf
- Legal Marijuana Market Size Worth $73.6 Billion By 2027 | CAGR 18.1%. Media Release: February 2020. https://www.grandviewresearch.com/press-release/global-legal-marijuana-market
- Cho, C.; Hirsch, R; Johnstone, S. “General and oral health implications of cannabis use.” Australian Dental Journal, 2005; 50(2):70-74