Oral Ulcers/Aphthae and Microbiota

Mouth ulcers, commonly known as canker sores, are painful sores that occur in the soft tissues of the mouth. While their exact causes are not fully understood, scientific research is increasingly uncovering a strong connection between mouth ulcers and the oral microbiota.
In this article, we will delve into the impact of microbial communities living in the mouth on mouth ulcers and explore how probiotics might play a role in managing these stubborn and discomforting sores.

Understanding Mouth Ulcers

Mouth ulcers are a common complaint that affects a significant portion of the population. They are usually small, round, or oval in shape, with a yellow or white center surrounded by a red border. The pain associated with mouth ulcers can range from mild discomfort to severe interference with eating, speaking, and oral hygiene. The exact cause of mouth ulcers is unknown, but several factors are thought to contribute to their development:

• Immune system dysfunction: An overactive immune response may cause inflammation in the oral mucosa, leading to ulcer formation.
• Genetic predisposition: Some individuals may have a genetic susceptibility to developing mouth ulcers.
• Nutritional deficiencies: Deficiencies in iron, vitamin B12, and folate have been linked to mouth ulcers.
• Hormonal fluctuations: Some women experience mouth ulcers during menstruation or pregnancy.
• Stress: Emotional stress can act as a trigger for mouth ulcers.
• Local trauma: Injuries to the oral mucosa, such as biting the cheek or tongue, can also lead to ulcers.

Oral Microbiota

The oral cavity hosts a diverse and complex community of microorganisms, including bacteria, fungi, viruses, and archaea, collectively known as the 'oral microbiota.' In a healthy state, the oral microbiota exists in a delicate balance, contributing to various oral functions such as digestion, immune regulation, and protection against pathogenic microbes. However, disruptions in this balance, known as dysbiosis, have been associated with various oral diseases, including periodontitis, tooth decay, and potentially mouth ulcers.

Oral Microbiota and Mouth Ulcers

Emerging research suggests that changes in the oral microbiota may play a significant role in the development of mouth ulcers. Several studies have reported differences in the composition of the oral microbiota between individuals with mouth ulcers and healthy individuals. These studies have observed the following:

• Reduced microbial diversity: The overall diversity of the oral microbiota tends to be lower in individuals with mouth ulcers.
• Increased abundance of certain bacteria: Certain bacteria, such as Streptococcus sanguinis, Prevotella intermedia, and Capnocytophaga ochracea, have been found in higher numbers in patients with mouth ulcers.
• Decreased abundance of other bacteria: Beneficial bacteria, such as Lactobacillus species, have been found in lower numbers in patients with mouth ulcers.

These changes in the oral microbiota may contribute to the development of mouth ulcers in several ways:

• Inflammation: An imbalance in the oral microbiota may lead to an increase in pro-inflammatory bacteria, triggering inflammation in the oral mucosa.
• Compromised mucosal barrier: Disruptions in the microbial community may compromise the integrity of the oral mucosal barrier, making it more susceptible to injury and inflammation.
• Immune system dysfunction: Changes in the oral microbiota may affect the immune system's response, potentially leading to an overactive immune response and ulcer formation.

The Role of Probiotics in Mouth Ulcers

Probiotics are live microorganisms that provide health benefits to the host when consumed in adequate amounts. These microorganisms have been extensively studied for their potential benefits in managing various gastrointestinal disorders. Recent research has also highlighted their potential roles in oral health, including the management of mouth ulcers. The mechanisms through which probiotics can contribute to oral health include:

• Competitive inhibition: Probiotics can outcompete harmful bacteria by making it difficult for them to adhere to and proliferate in the mouth. This reduces the impact of pathogenic bacteria by competing for nutrients and adhesion sites.
• Production of antimicrobial substances: Some probiotics produce antimicrobial substances, such as bacteriocins, which can inhibit the growth of pathogenic bacteria.
• Modulation of the immune system: Probiotics can interact with the immune system to promote a balanced immune response and reduce inflammation.
• Strengthening the mucosal barrier: Some probiotics contribute to strengthening the oral mucosal barrier, protecting it from injury and inflammation.

Several studies have explored the use of probiotics in the management of mouth ulcers with promising results:

• Reduction in ulcer frequency and severity: Some studies have reported a reduction in the frequency and severity of mouth ulcers in patients who consumed probiotics.
• Improvement in healing: Probiotics may accelerate the healing of mouth ulcers.
• Modulation of oral microbiota: Probiotic supplementation may contribute to the restoration of a healthy oral microbiota.

Selecting the Right Probiotics

The effectiveness of probiotics depends on various factors, including the probiotic strain, dosage, and duration of use. Several probiotic strains have been studied for their potential benefits in oral health, including:

• Lactobacillus species: Lactobacillus rhamnosus and Lactobacillus reuteri, among others, have shown promising results in studies on mouth ulcers. These strains have demonstrated the ability to reduce the frequency and severity of ulcers, accelerate healing, and balance the oral microbiota.
• Bifidobacterium species: Bifidobacterium bifidum and Bifidobacterium infantis may potentially contribute to the healing of mouth ulcers. Due to their anti-inflammatory properties, these bacteria can reduce inflammation in the oral mucosa and speed up the wound healing process. Moreover, by maintaining the balance of the oral microbiota, they can also lower the risk of recurrence of ulcers.
• Akkermansia muciniphila: A bacterium typically known for its role in gut microbiota, Akkermansia has potential effects on oral health as well. While mouth ulcers, or canker sores, manifest as painful lesions in the oral mucosa, Akkermansia's anti-inflammatory properties may play a crucial role in the healing process of these lesions. By strengthening the mucosal barrier, Akkermansia can reduce inflammation in the mouth, thereby preventing the formation of mouth ulcers or contributing to the healing of existing sores.

When choosing probiotics for mouth ulcers, it is important to consult with a healthcare professional to select the most appropriate strain and dosage. Especially probiotic chewable tablets that are taken orally may be very effective for mouth ulcers. Additionally, it is crucial to look for probiotics that have been specifically tested and proven effective in clinical studies.

Other Strategies for Managing Mouth Ulcers

Other strategies that can help manage mouth ulcers include:

• Balanced diet: A well-balanced diet supports overall health and can help prevent nutritional deficiencies that may be associated with mouth ulcers.
• Stress management: Stress can act as a trigger for mouth ulcers. Stress management techniques such as regular exercise, yoga, and meditation may help reduce the frequency of mouth ulcers.
• Good oral hygiene: Good oral hygiene practices can help maintain the balance of the oral microbiota and prevent the formation of mouth ulcers.
• Zinc supplementation: Some studies suggest that zinc deficiency may be associated with mouth ulcers. Zinc supplementation may help manage mouth ulcers.

Conclusion

Mouth ulcers are a common and discomforting condition that affects a wide population. Increasing evidence reveals a strong relationship between mouth ulcers and the oral microbiota. Due to their potential in balancing the oral microbiota and improving oral health, probiotics offer a promising solution for managing mouth ulcers. In particular, their ability to reduce inflammation and strengthen the mucosal barrier may prevent the formation of ulcers or accelerate the healing of existing ulcers. However, it is important to consult with a healthcare professional before starting any probiotic supplement to select the most appropriate strain and dosage. It is also recommended to adopt a healthy lifestyle to reduce the risk of mouth ulcers.

San Francisco, California, USA
Ali R. Akın