Many US states and Canada have legalized the personal use and research of Cannabis. With full legalization, we have seen a surge of such use, in its variety of forms (smoking or eating). In fact, in a survey done, over one third of respondent reported using cannabis at least once by their 15th birthday. Cannabis has over 350 chemicals, with the two main psychoactive and physiologically active chemicals being THC (delta-9-tetrahydrocannabinol) and CBD (cannabidiol). Unfortunately, the scientific research on the implications of oral health and oral health care are very limited. As most of us will encounter patients actively using cannabis, it is important to know how to manage and treat these patients accordingly.
23 studies were reviewed, following a link between cannabis use and oral health or to dental care.
Cannabis and Periodontal Health
In the studies evaluated, cannabis use has a significantly higher associated with poorer periodontal health. In one study, over half of the participants who used cannabis for 15 cumulative years, were diagnosed with periodontal disease. This was also true when controlling for possible alcohol use, tobacco use, or previous periodontal disease diagnosis.
Although there is no scientific finding linking cannabis use to periodontal disease through a physiological pathway, there are some strong hypotheses made. First, the combustion heat of cannabis during use can cause dryness of the oral mucosa. Furthermore, THC activates the parasympathetic nervous system, therefore reducing salivary flow. This xerostomia can lower the buffering capacity of saliva, therefore compromising the oral cavity to fungal, bacterial or viral infections.
Cannabis use has also been linked to poorer oral hygiene practices. It has been shown that cannabis users brush their teeth and visit their dentist less frequently. Cannabis users also have a higher chance of using other harmful substances such as tobacco, which can further damage periodontal health.
Cannabis and Cavities
There is no significant increase in dental caries with cannabis use. In the studies examined, there is no difference in the caries incidence rate of cannabis users to non-users.
Cannabis and Oral Cancer
There is no significant association between cannabis use (smoking or eating) and an increased risk to oral cancer. However, some studies have shown a positive association to oropharyngeal cancer. Although research with cannabis and cancer are still at its infancy, THC has been shown to have both carcinogenic and anti-carcinogenic properties, which can account for its site-specific carcinogenic effects.
Cannabis and Clinical Care
The most common difficulty stated by oral health professionals regarding patient cannabis use is the reluctance of the patient to disclose this information, and therefore the inability to obtain an accurate medical history. Furthermore, patients who are under the influence of cannabis during their appointment cannot give informed consent to treatment, which leads to missed or postponed appointments.
Furthermore, cannabis use and local anesthesia containing epinephrine can heighten the tachycardia brought upon by cannabis use alone. Patients who use cannabis 72 hours before general anesthesia experience sustained tachycardia, which can trigger a life threatening cardiac event.
Going Forward
It is our job to inform our patients about cannabis use and its potential side effects. It is also our job to clinically manage those patients who use cannabis. We have to inform our patients and staff when one needs extra care with periodontal health, home oral hygiene and more frequent visit to the dentist. As the legalization of cannabis becomes more widespread, so does it acceptance in a social and cultural context. We must be prepared to continue to treat our patients with the latest knowledge available.