The Effects of Paan (Betel Leaf) On Teeth and Oral Mucosa: A Comprehensive Review

Chewing betel leaf with or without various additives is popular in the Indian culture.  Betel leaf has been documented to possess many anti-inflammatory and antibiotic-like effects. These effects have been postulated to arise due to presence of polyphenols, sterols and terpenes in betel leaf. However, betel leaf consumption may also promote many harmful effects in the oral mucosal, like oral submucous fibrosis and oral cancer. All these things have been reviewed here.

The use of herbal medicine in dentistry and dental practice has grown exponentially with time. Currently, herbal medicine is considered as an effective oral hygiene aid [1].  Paan (betel leaf), a traditional chewing substance which is popular in South and Southeast Asia, is composed of betel leaves, areca nut, slaked lime, and sometimes other flavouring agents or spices. History of consuming paan leaves in India dates back to antiquity. While it holds tremendous cultural significance and is consumed for its stimulant effects, the practice of chewing paan has been associated with a range of oral health issues and effects. This review article explores the effects of paan on teeth and oral mucosa, focusing on both the beneficial and harmful consequences for oral health.
Chemical Composition of Paan
The ingredients of paan vary regionally, but the core components include
Betel leaf (Piper beetle): Known for its mild stimulant properties, betel leaves contain alkaloids like pipeline, which has mild antimicrobial effects.
Areca nut (betel nut): A psychoactive substance that contains alkaloids such as arecoline, which may have effects on the central nervous system.
Slaked lime (calcium hydroxide): Enhances the release of alkaloids from the areca nut and is thought to increase the absorption of these substances into the body.
Flavouring agents: These may include spices, sweeteners, or tobacco, which can influence the overall health impact of paan.
Betel leaf per se contains sterols, terpenes, flavonoids and catechol’s, which contribute top its anti-inflammatory and antibiotic effects. 
Effects on Teeth: The impact of paan on dental health is primarily due to the combination of areca nut, slaked lime, and the mechanical act of chewing. The effects can be categorized into the following areas:
Staining and Discoloration: The betel leaf itself does not significantly stain teeth, but the areca nut and slaked lime can cause persistent discoloration. The tannins and polyphenols in the betel leaf can contribute to brownish staining, particularly when paan is chewed frequently. Additionally, the alkaline nature of slaked lime can alter the pH in the oral cavity, facilitating the deposition of pigments on the teeth.
Dental Erosion and Enamel Damage: Slaked lime, being highly alkaline, can erode tooth enamel over time. The abrasive nature of areca nut particles also contributes to wear on the enamel, making teeth more susceptible to decay. Repeated exposure to these substances leads to thinning of the enamel, which can exacerbate tooth sensitivity and increase the risk of cavities.
Increased Risk of Dental Caries: Frequent paan chewing has been associated with an increased risk of dental caries. The high carbohydrate content from added sweeteners in paan provides a substrate for bacteria in the oral cavity. Combined with the enamel-damaging effects of areca nut and slaked lime, this creates an environment conducive to tooth decay. However, betel leaf or paan per se may have antibacterial and anti-biofilm activity, as seen against Bacillus gamogenesis, a bacterium causing dental caries with biofilm [2]. 
Periodontal Disease: The chronic use of paan has been linked to periodontal disease, characterized by inflammation and infection of the gums. The local irritants in paan, particularly from the lime and areca nut, contribute to the formation of plaque and tartar on the teeth, leading to gum irritation, bleeding, and even tooth loss in severe cases. However, betel leaf itself has anti-inflammatory and antibacterial effects. The harmful and carcinogenic effects are mainly due to the additives present in betel leaf. An image of betel leaf is appended in figures 1 and 2 below.

Figure 1: Paan leaf (source: - internet)

Basis of action
Antibacterial effect of paan: Betel leaf is known to have antibacterial effects. Found in high concentrations in the extracts of piper betel leaf is sterol, which is a biologically active molecule that is responsible for the antibacterial effects [3]. Hence betel leaf has bene used as an essential component of dentifrices or toothpastes, but long-term use may lead to enamel surface roughness [2,4].
Antioxidant effects: Vitamin C and Polyphenolice compounds found in betel leaves can neutralize harm-ful free radicals and thereby lower inflammation [5].
Effects on Oral Mucosa:  Paan chewing has both short-term and long-term effects on the soft tissues of the oral cavity, which can range from mild irritation to severe pathological changes. 
Oral Mucosal Irritation: The alkaline nature of slaked lime when present in paan can cause local irritation of the soft tissues in the mouth, including the gums and inner cheeks. The lime (calcium hydroxide) used along with paan can lead to an alkaline pH, thereby triggering ROS (reactive Oxygen species) release and thus causing irritation of the oral mucosa and hyperplasia [6]. This can lead to a burning sensation, redness, and swelling, which may progress to more serious mucosal lesions with prolonged use.
Leucoplakia and Oral Cancer: One of the most concerning long-term effects of paan consumption is its potential carcinogenicity. The areca nut is classified as a Group 1 carcinogen by the International Agency for Research on Cancer (IARC) [7]. Chronic use of paan, especially when combined with tobacco, increases the risk of developing leucoplakia, a condition characterized by the formation of white patches on the mucosa, which are precursors to oral cancer. Studies have shown that individuals who chew paan are significantly more likely to develop oral cancers, particularly in the mouth, tongue, and throat.
Submucous Fibrosis: Another significant oral health consequence of regular paan use is oral submucous fibrosis (OSF), a condition where the connective tissues in the mouth become stiff and fibrous, leading to restricted mouth opening, pain, and difficulty in swallowing [8]. OSF is considered a pre-cancerous condition, and it is more commonly seen in individuals who chew paan mixed with tobacco.
Ulcers and Soft Tissue Damage: The mechanical act of chewing areca nut, combined with the abrasiveness of the ingredients, can lead to the formation of oral ulcers, particularly in the mucosa of the cheeks and gums. These lesions can be painful and may become infected, further complicating the oral health of paan users.
Health Risks and Addictive Potential: Apart from the direct effects on oral health, the ingredients in paan, particularly areca nut, are associated with addictive behaviours. The psychoactive effects of arecoline can lead to dependence in some individuals, which further increases the frequency of paan consumption and the risk of developing the oral health issues outlined above. Arecoline causes neurological effects for the chewers such as initiating a sense of euphoria, being alert and attentive, and feeling relaxed while chewing [9]. The inclusion of tobacco in some paan preparations only amplifies these risks, contributing to systemic health issues such as cardiovascular disease, lung cancer, and respiratory disorders.
Antibacterial effects: Other than this, paan leaf alone can reduce pathogenic bacteria present in mouth cavity. This has been discussed earlier.
Antifungal effects: We have observed antifungal effects of paan leaf. It is also useful as a medium for Dalmau technique for yeast identification. 
Potential Benefits of Paan: Despite its potential harms, some components of paan offer mild benefits. Betel leaves, for instance, have antimicrobial properties that can reduce the growth of oral bacteria and may help in controlling bad breath [10]. Some studies suggest that chewing paan with a mix of spices or herbs may aid digestion and provide temporary relief from certain oral discomforts. However, these benefits are generally outweighed by the negative effects when consumed regularly or in large quantities.

Betel leaf is very popular as mouth freshener in India and other South East Asian countries. It is consumed singly or with additives like areca nut and tobacco.  Various properties of betel leaf include antioxidant, antidiabetic, antifungal, antiulcerogenic, antiplatelet, immunomodulatory, antileishmanial, ant amoebic, anti-inflammatory, ant filarial and antibacterial [11]. However, chewing paan may also promote some premalignant lesions and even oral cancer. The adverse effects of chewing betel leaf arise more commonly due to the areca nut and other sweeteners and additives present in ready-to-eat paan. These things concern all and hence are of tremendous importance for clinicians, cancer specialists and also public health specialists at large. More research should be dedicated to this field.

While paan holds cultural significance and may offer some short-term oral benefits, its long-term impact on teeth and oral mucosa may be predominantly harmful. The combination of areca nut, slaked lime, and the frequent mechanical irritation caused by chewing leads to a range of oral health issues, including tooth discoloration, enamel erosion, periodontal disease, mucosal lesions, and an increased risk of oral cancer. Public health campaigns are essential to raise awareness about the detrimental effects of paan and to encourage safer oral habits. Individuals who engage in regular paan consumption should be counselled on the risks and consider reducing or eliminating their use to preserve oral and overall health.