Underweight and Dental Health: How BMI Influences Malocclusion and Bruxism

Understanding Bruxism and Malocclusion

What is Bruxism?

Bruxism, defined as the parafunctional grinding of teeth, is an oral habit consisting of involuntary rhythmic or spasmodic non-functional gnashing, grinding, or clenching of the teeth other than chewing movements of the mandible. Although this definition is commonly used by dental professionals, there is no link to the sleep-wake state of the condition. Sleep bruxism is clearly defined as ‘an oral parafunction characterized by grinding or clenching of the teeth during sleep that is associated with excessive sleep arousal activity’. However, awake bruxism still lacks a clear definition.


As a patient advocate for those suffering from clenching, grinding, facial pain, and headaches, I have seen the significant impact bruxism can have on individuals’ lives. Bruxism can lead to a range of dental and health issues, including severe tooth wear, muscle pain, tension-type headaches, and temporomandibular joint (TMJ) disorders. Whether occurring during sleep or while awake, bruxism can greatly affect one’s quality of life.

Defining Malocclusion

Malocclusion refers to the misalignment of teeth when the jaws are closed. This misalignment can manifest in various ways, such as crowded teeth, crossbites, overbites, and underbites. Each of these conditions not only affects the appearance of one’s smile but also has functional implications. Malocclusion can interfere with proper chewing, increase the risk of tooth decay and gum disease, and even cause speech problems.

Causes of Malocclusion

Malocclusion can be caused by a variety of factors, including genetic predisposition, developmental issues, and habits such as thumb sucking during childhood. Injuries to the jaw and teeth can also result in misalignment. Understanding these causes is crucial for developing preventive strategies and effective treatments.

Types of Bruxism

There are two main types of bruxism: awake bruxism and sleep bruxism. Awake bruxism often occurs during periods of concentration, stress, or anxiety, and involves clenching or grinding of the teeth while awake. Sleep bruxism, on the other hand, happens involuntarily during sleep and is often associated with arousal activities during sleep. Both types of bruxism can have detrimental effects on dental health and overall well-being.


The Connection Between BMI and Dental Health

Impact of Underweight Status on Dental Health

Underweight individuals, particularly those with a BMI below 18.5, have been found to have a significant correlation with malocclusion. This relationship is due to various factors, including skeletal maturation and nutritional deficiencies that can affect tooth and jaw development. As a patient advocate, it is important to highlight the importance of maintaining a healthy BMI not just for general health, but also for optimal dental health.

Skeletal Maturation and Malocclusion

There is a positive correlation between BMI and cervical vertebral maturation. Underweight individuals often exhibit skeletal prematurity, which can contribute to malocclusion due to underdeveloped jaw structures. Proper skeletal development is essential for maintaining the alignment and health of the teeth and jaw.

Diet & Dental Health

Nutritional Deficiencies And Dental Health

Nutritional deficiencies commonly associated with being underweight can impair dental health. Essential nutrients such as calcium, vitamin D, and phosphorus are critical for the development and strength of teeth and jawbones. A lack of these nutrients can lead to weaker bones and teeth, increasing the risk of malocclusion and other dental problems.

Clenching and Its Effects on Tooth Alignment

Daytime Clenching and Tooth Movement

Clenching during the day exerts significant force on the teeth, which can lead to tooth movement and the development of malocclusion. The increased tightness of proximal tooth contact caused by clenching is a key factor in this process. According to present-day knowledge, in cases with frontal crowding, the tangential stiffening of the anterior teeth is inadequate. This means that the front teeth are not adequately supported, making them more susceptible to movement and misalignment.


During maximum jaw opening and mandibular protrusion, translatory and rotational force components resulting from the elastic deformation of the mandible can cause the movement of rotated front teeth. This can lead to further misalignment and crowding, which can exacerbate dental problems. Additionally, tongue thrusting and front to lateral bruxism lead to force vectors in the vestibular direction, affecting the delicate periodontal tissues. These statements are confirmed by in-vivo experimental studies measuring the amount of tooth displacement during test persons’ functional movements.


Gender Differences in Clenching Impact

Research indicates that males tend to have a greater bite force compared to females, making them more susceptible to tooth movement and malocclusion due to clenching. This difference explains why malocclusion related to bruxism is more prevalent in males. The greater bite force in males can lead to more pronounced tooth displacement and misalignment, particularly in the presence of bruxism.


In the long term, anterior crowding will mostly trigger incorrect anterior guidance, meaning that guidance is predominantly by the rotated or ectopically positioned front tooth, with subsequent overloading of the antagonist. This can lead to increased wear and tear on the teeth, further contributing to dental issues.

Psychological Factors Influencing Clenching

Stress and anxiety are significant psychological factors that can lead to increased clenching and grinding, exacerbating dental issues. Many individuals clench or grind their teeth as a response to stress, often without being aware of it. This involuntary habit can place tremendous pressure on the teeth and jaw, leading to misalignment, pain, and damage to the TMJ and muscles of mastication.


Addressing the psychological factors that contribute to clenching is crucial for managing bruxism and its effects. Techniques such as stress management, relaxation exercises, and cognitive-behavioral therapy can be effective in reducing the frequency and intensity of clenching and grinding.

Malocclusion, Masticatory Performance, and BMI

How Malocclusion Affects Eating

Malocclusion can impair an individual’s ability to process and break down food effectively, reducing masticatory performance. This inefficiency can contribute to underweight conditions, as it may hinder proper nutritional intake and digestion. When the teeth are misaligned, it becomes difficult to chew food properly, which can lead to inadequate nutrient absorption and digestive issues.


The improper alignment of teeth can also cause discomfort while eating, leading individuals to avoid certain foods that are harder to chew. This can result in a limited diet, further contributing to nutritional deficiencies and underweight status.

The Cycle of Malocclusion and Underweight

The relationship between malocclusion and underweight status can be cyclical. Malocclusion leads to reduced masticatory performance, which in turn can exacerbate underweight conditions. Conversely, being underweight can contribute to skeletal issues that result in malocclusion. This cycle can be challenging to break, as each condition can perpetuate the other.


For instance, an individual with malocclusion may struggle to eat a balanced diet, leading to weight loss and a lower BMI. This underweight status can then impair skeletal development, further worsening the malocclusion. Addressing both malocclusion and nutritional deficiencies simultaneously is essential for breaking this cycle and improving overall health.

Impact on Overall Health

Malocclusion and poor masticatory performance can have broader health implications, including gastrointestinal issues and decreased quality of life. When food is not adequately chewed, it can lead to digestive problems such as bloating, gas, and indigestion. Additionally, the discomfort and pain associated with malocclusion and bruxism can affect an individual’s ability to enjoy meals and maintain a healthy diet.


Addressing malocclusion and improving masticatory performance can significantly enhance overall health and well-being. Proper dental alignment allows for efficient chewing, better nutrient absorption, and improved digestive health. It also reduces the risk of dental issues such as tooth decay and gum disease, contributing to a healthier mouth and body.

Clinical Indicators and Diagnosis of Bruxism

Maximum Occlusal Tooth Wear

Tooth wear is a common indicator of bruxism, often assessed through the maximum occlusal tooth wear index. This index measures the extent of wear on the surfaces of the teeth, which can reveal the impact of grinding and clenching habits. Significant wear patterns, such as flattened or chipped teeth, can indicate chronic bruxism. For those experiencing facial pain and headaches, tooth wear is a crucial sign to look for, as it often correlates with the severity of their symptoms.

Other Clinical Signs

There are additional clinical indicators of bruxism that can help in diagnosis. These include:

  • Buccal Mucosa Ridging: This occurs when the lining of the cheeks develops ridges or lines due to continuous pressure from the teeth. It’s a visible sign often seen in individuals who clench their teeth.
  • Tongue Indentation: Also known as scalloped tongue, this condition occurs when the sides of the tongue develop indentations from being pressed against the teeth repeatedly.
  • Palatal Torus: This is a bony growth on the roof of the mouth. While not directly caused by bruxism, its presence can be more common in those who clench or grind their teeth.
  • Mandibular Torus: Similar to the palatal torus, this bony growth occurs on the lower jaw and can be influenced by the forces exerted during bruxism.

These signs are crucial for non-clinical individuals to recognize, as they often accompany the pain and discomfort associated with clenching and grinding.

Use of Diagnostic Tools

Advanced diagnostic tools can provide more accurate assessments of bruxism. For instance, electromyography (EMG) measures the electrical activity of muscles during clenching and grinding, offering detailed insights into the severity of bruxism. Polysomnography, a type of sleep study, can monitor bruxism during sleep and is especially useful for diagnosing sleep bruxism.


While these tools are typically used in clinical settings, being aware of them can help patients understand the comprehensive nature of diagnosing bruxism and advocate for themselves during medical appointments.

Self-Reported Bruxism

Self-reported questionnaires are commonly used for large-scale studies to assess the prevalence of bruxism. These questionnaires can help identify patterns and triggers of bruxism in individuals. However, it’s important to note that self-reports may have limitations in accuracy, as they rely on individuals’ awareness and recall of their symptoms.


For those experiencing facial pain, headaches, and other symptoms associated with bruxism, self-reporting can be a valuable tool in communicating their experiences to healthcare providers.

Addressing Bruxism and Malocclusion

Importance of Early Detection

Early detection of bruxism and malocclusion is crucial for preventing long-term dental issues. Regular dental check-ups and monitoring for signs of clenching and grinding can help manage these conditions effectively. Catching these issues early can prevent more severe dental damage and reduce the risk of chronic pain associated with TMJ disorders and tension-type headaches.

Strategies for Managing Bruxism

Management strategies for bruxism include a combination of behavioral and medical approaches:

  • Stress Reduction Techniques: Practices such as mindfulness, yoga, and meditation can help reduce the stress and anxiety that often trigger bruxism.
  • Occlusal Appliances: Night guards or splints can protect the teeth from the damaging effects of grinding during sleep. These devices are custom-made by dentists to fit comfortably and provide a barrier between the upper and lower teeth.
  • Behavioral Therapies: Cognitive-behavioral therapy (CBT) and Biofeedback devices can help individuals change the behaviors and thought patterns that contribute to bruxism. This approach is particularly effective for awake bruxism.

Addressing the underlying stress and anxiety that contribute to clenching and grinding is essential for long-term management.

Orthodontic Treatments for Malocclusion

Orthodontic treatments can correct malocclusion and improve dental alignment. Options include:

  • Braces: Traditional metal or ceramic braces gradually move the teeth into proper alignment.
  • Clear Aligners: These removable aligners, such as Invisalign, are a more aesthetic option for straightening teeth.
  • Retainers: Post-treatment retainers help maintain the new alignment of teeth after braces or clear aligners.

Orthodontic treatments can significantly reduce the risk of future dental issues and improve overall oral health.

Role of Diet and Nutrition

A balanced diet rich in essential nutrients supports dental health and can help prevent malocclusion and other dental issues. Nutrients such as calcium, vitamin D, and phosphorus are vital for maintaining strong teeth and bones.

Lifestyle Modifications

Incorporating lifestyle modifications such as avoiding hard foods, practicing good oral hygiene, and managing stress can help in managing and preventing bruxism and malocclusion. Simple changes like avoiding chewing gum and being mindful of teeth clenching during the day can make a significant difference.


By understanding these clinical indicators and adopting effective management strategies, individuals can take proactive steps towards improving their dental health and alleviating the pain and discomfort associated with bruxism and malocclusion.

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