Course Introduction

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Throughout history, plants have occupied central roles in health beliefs and practices, healthcare systems, sociopolitical controversy, and healthcare reform. In the 19th century, lobelia (Lobelia inflata), a plant indigenous to the North American continent and used medicinally for centuries by indigenous peoples, gained attention. The plant was used both to aid respiration and to induce vomiting for various health and spiritual concerns (Moerman, 1998). Lobelia became the focus of health care during a period of extensive healthcare reform (Berman & Flannery, 2001). There was debate about the safety of lobelia just as there is today with other controversial plants, such as ephedra (Ephedra sinensis), tobacco (Nicotiana tabacum), and marijuana (Cannabis spp.). Medicinal use of plants continues to be one of the cornerstones of healthcare cultures and systems around the world. Because of their accessibility, cultural history, and relatively safe record of traditional use, medicinal plants remain at the center of health care as traditional medicine (World Health Organization, 2013). Over the years, leading plant scientists such as Farnsworth and Soejarto (1991) reported the existence of more than 250,000 higher species of chemically distinct plants on Earth, of which between 35,000 and 70,000 have been used medicinally over the centuries. It is estimated that only a fraction of all flower-bearing plants have been examined and only a small subset have had their chemical constituents identified or had their healing properties researched in double-blind, placebo-controlled trials. The potential of the plant world for producing cures for disease and relief from everyday discomfort is recognized by botanists, ethnobotanists, and pharmacognosists (people who pursue drug discovery from plants). The public continues to be a driving force in medicinal plant use. People follow their time-honored plant-oriented healing traditions in self-care practices. They also urge the scientific community to develop new drugs and applications.

All healthcare paradigms – self-care, traditional medicine, and biomedical – are interested in the medicinal use of marijuana, but this course will specifically focus on the dental realm. This plant, which has been employed for centuries in self-care and traditional medicine, is now the focus of much interest in terms of biomedical development for use in alleviating diseases and in chronic pain management. Yet, as will be discussed in this course, marijuana is federally classified as an illegal drug.

This course is an introduction to the genus Cannabis (and species such as sativa and indica). It presents a synopsis of the plant’s history and the scientific information currently available to guide public and professional exploration, from self-care to biomedicine and clinical trials.

A review of the literature produces thousands of reports, theoretical and population research papers, and books, on medicinal marijuana. Few clinical trials exist, however, that might begin to answer some of the questions from the public and health professionals about the physical and psychological effects of the plant and its constituents. This course offers a synopsis of traditional and biomedical data about the plant and the issues related to public and professional use in an attempt to answer some of the most common questions that oral healthcare professionals (OHCPs) may have when counseling those currently using, or who are deciding whether to use marijuana. Marijuana, for both medicinal and recreational use, is a highly controversial and disputed subject. It is important to note that it is not the purpose of this course to sway opinion for or against marijuana but to inform based on current medical evidence.

Although healthcare professionals and leadership, including those at the National Institutes of Health (National Academies of Science, Engineering, and Medicine, 2017) and the World Health Organization (2013), call for medical marijuana research, federal prohibition of marijuana use in the United States creates a challenge for scientific analysis of this illicit drug. However, public attraction to marijuana for medical and recreational use drives medical science to explore emerging evidence of the role of the endocannabinoid system in health and disease. Establishment of a body of clinical-trial research on marijuana to complement current evidence is necessary to inform the public and establish best-practice guidelines for healthcare professionals. However, as will be demonstrated in this course, even if federal laws were to loosen or be abolished, the feasibility of developing and administering robust clinical trials would be met with considerable hurdles. This course includes references to the most current research evidence available, drawing, when possible, on clinical trial research.

There is much to learn about medicinal marijuana from evidence other than clinical trials. This course includes historical data and evidence from in vitro studies, literature reviews, meta-analyses, surveys, and community health studies that have contributed in a meaningful way to current scientific understanding of the health outcomes witnessed in the public sphere, where marijuana use is proliferating.

This course adopts the common name “marijuana” to refer to the species Cannabis sativa and C. indica, as well as hybrids of the two. The science of botanical nomenclature requires that a genus and species name be italicized and that the genus be capitalized. Much of the medical and scientific literature refers to marijuana as “cannabis” not Cannabis spp., and state registries use the term “marijuana,” not Cannabis. Marijuana is the term commonly employed by the public. Although supporters of marijuana use and legalization are concerned about the social stigma surrounding the use of the word “marijuana,” there is no intention to further stigmatize the plant in this course. The common name for the plant was chosen for the title of this course because it is likely to be more recognizable by OHCPs seeking continuing education courses that include the information provided here. For consistency, ease, and clarity, the term “marijuana” will be used. Botanical names may also be employed to add specificity to the information presented.

Designed for dentists, dental hygienists, and dental assistants, this intermediate-level course will review the pharmacology and current state of medicinal marijuana as it relates to oral health care. The information presented in this course should be considered essential knowledge for all OHCPs, both seasoned and newly credentialed.

Disclaimer: Throughout history, plants have been at the center of many controversies about health care. Marijuana (Cannabis spp.) is one of those plants. Medicinal marijuana is a highly controversial topic in the United States today. The act of authoring this course should not be misconstrued as agreement with or opposition to the use of marijuana, recreationally or medicinally, or alignment with the movement to legalize marijuana.

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