Cannabis Chronicles

Cannabis sativa (C. sativa) is considered one of the world’s oldest cultivated plants, and the enigmatic herb has been interwoven with human existence since the ancient world. The history of its use has been complex and variable across cultures, reflecting shifting societal attitudes, political dynamics, and evolving scientific understanding of the plant’s properties. In the US, the tension between its psycho-active and therapeutic uses is playing out today as a multi-dimensional debate as it transitions from a reviled substance with no medicinal value to one with therapeutic potential for human health, including oral health.

Cannabis began its human interaction in Asia where it was a favored element of spiritual and medicinal practices, and as a source of textile fiber (Hemp). Several hundred pharmacologically active compounds can be produced from C. sativa, which include cannabinoids, terpenes, and flavonoids. The most widely known cannabinoid of therapeutic value is cannabidiol (CBD). As a group, these active metabolites are known for their anti-inflammatory, anti-epileptic, antioxidant, antimicrobial, analgesic, and anxiolytic properties.^1,2 Although the same species of plant, the difference between medicinal cannabis (marijuana) and hemp lies in the concentration of the psychoactive cannabinoid D9-tetrahydrocannabinol (THC).

Legally, Hemp and its derivatives can contain no more than 0.3% concentration of THC as outlined by the 2018 Federal Farm Act. Prior to the 1990s the concentration of THC in marijuana was under 2%, but potency began to increase as more states approved its recreational use and the industry took advantage of the lack of regulation, taking a page from “big” tobacco. In 2017 popular marijuana strains sold in Colorado dispensaries reached between 17% and 28%, making the manufactured products more addictive and prone to abuse and accidental overdose.³

Medicinal uses of cannabis were first recorded around 2700 BC in China, where it was used for a variety of conditions, including pain and rheumatism.² From there, the plant made its way to India and Africa, and then to Europe, through trade along the silk road. For treatment of diseases in the oral cavity, it was a common ingredient in folk remedies for toothache, gum inflammation, and prevention of dental caries.^2,4

The American story of Cannabis began in colonial America with the growing of Hemp. It was a significant agricultural product and critical to the economic well-being at the time, as it was fast-growing and versatile, used to make paper, clothing, rope, and even used as legal tender in some of the colonies. As a medicine, cannabis was first chronicled in the 1850 United States Pharmacopoeia and, along with morphine, was added to patent formulations for pain, nausea, and the treatment of conditions such as migraine and epilepsy.² Given to an unsuspecting public, unregulated “quack” medicines led to a rapid increase in morphine addiction across the country. At the same time, as more of the population migrated from the country to cities for work and the distance between farm to marketplace increased, many food producers were adding dangerous substances like formaldehyde to prevent spoilage.

The year 1906 saw the passage of the first significant consumer protection law, the Pure Food and Drug Act. Meant to raise standards in these industries by regulating their passage through interstate commerce, the law in essence required “truth in labeling” to ensure that drugs containing addictive substances such as alcohol, morphine, and cannabis be accurately labeled as to content and dosage. This marked the beginning of regulatory drug policy in the US and the emergence of the Food and Drug Administration (FDA).

Smoking marijuana became popular with the rise of the golden age of Jazz through the 20s and 30s, but concerns increased over its health and societal impacts, especially on youth. Meant to sway public opinion, an anti-marijuana propaganda campaign known as “Reefer Madness” was launched to portray it as a dangerous drug that led to violent and criminal behavior.⁵ In 1937, the federal government prohibited cannabis use and sale with the passage of the Marihuana Tax Act, and shortly thereafter, it was removed from the US Pharmacopoeia. By the 1950s, the possession of marijuana earned a mandatory jail sentence. The counterculture movement in the 1960s and 1970s marked a time of renewed interest in and greater acceptance of the drug’s recreational use as the Vietnam war ended and more young people turned away from living in accordance with prevailing social norms.

The war on drugs began in earnest with the passage of the Controlled Substances Act of 1970. All substances regulated under existing federal law were categorized into one of five schedules, based upon potential for abuse, dependence liability, and medical use. As a most restricted, schedule I substance, developing an evidence-base for the therapeutic use of cannabis was greatly limited. The lack of meaningful research on short- and long-term health effects has been viewed as a significant barrier in the scientific understanding of cannabis, the guidance of public policy on use, and its impact on the nation’s public health, according to a 2017 report by The National Academies of Sciences, Engineering, and Medicine.⁶

Due to the US restriction, most of the early research on medicinal cannabis was conducted outside of the US, in Israel and Brazil. In 1960, a team of Israeli scientists, led by Dr Raphael Mechoulam, was the first to discover the chemical structure of CBD and THC molecules in the cannabis plant. Further research led them to identify the Endocannabinoid System (ECS), which is now recognized as a complex biological system that regulates several cognitive and physiological pathways, and whose CBD receptors mediate the pharmacological effects of the plant.⁷

The 1990s ushered in the medical marijuana movement as public sentiment began to shift, with scientific evidence increasingly demonstrating its therapeutic potential to treat conditions such as chronic pain and epilepsy. This prompted several states to begin decriminalization and legalization efforts. In 1996, California became the first state to legalize medicinal cannabis use under the supervision of a physician with the passage of the Compassionate Care Act. To date, there are four drugs based on cannabinoids that the FDA has licensed for medical use by prescription only, and it has not approved the use of cannabis to treat any specific condition due to lack of clinical trials demonstrating safety and efficacy.

Given emerging knowledge on the therapeutic benefits of medicinal cannabis and discovery of the ECS with its network of receptors dispersed throughout the oral cavity, research interest is increasing into discerning the mechanisms of action of CBD and other active metabolites on oral tissues.⁸ Potential promising applications for dentistry include modulation of the inflammatory response in periodontal disease and post-extraction pain management. Chronic, long-term recreational use of marijuana can be destructive to oral health. Like smoking tobacco, it has been associated with the development of leukoplakia, periodontal complications, and potential increased risk of head and neck cancers. However, the evidence to link marijuana use with oral diseases is limited and contradictory in the current published literature.⁹

In the last few years, cannabinoid-containing products have exploded onto the market and have joined the legions of other unregulated “natural supplements” and vitamins on drug store shelves. Some of these have targeted the consumer looking for oral health care products such as CBD-containing toothpastes, CBD-infused oral sprays and mouthwashes, and CBD chewing gum. With limited research on efficacy, safety, and quality, their claims for use remain unsubstantiated.

After completing an extensive scientific and medical review of cannabis, in September 2023, the Department of Health and Human Services (HHS) was confident in recommending to the Drug Enforcement Agency (DEA) that the reclassification of marijuana from a Schedule I to Schedule III controlled substance be considered. This would mark a significant shift in marijuana policy at the federal level and significantly change the economic dynamics for the industry.

Today marijuana laws are changing at a rapid pace across the country. Currently, 36 states and the District of Columbia have legalized medical marijuana to treat certain qualifying conditions, and 54% of the US population lives where cannabis is legal for recreational use. The continuing debate on cannabis demands careful consideration of competing interests as society wrestles with tension between medicinal benefits, social perceptions, potentially emergent “big” cannabis, and public health concerns. Developing a balanced, evidence-based regulatory structure will require a collaborative and informed discussion among all stakeholders. The story continues to unfold.