Mastering Occlusion and Parafunction: A Comprehensive Guide to Steven D. Bender’s “Occlusion, Function, and Parafunction”

Mastering Occlusion and Parafunction: A Comprehensive Guide to Steven D. Bender’s “Occlusion, Function, and Parafunction”

Introduction

In dentistry, parafunctional activities—those that fall outside of normal oral functions—like bruxism (tooth grinding) and cheek chewing can lead to significant long-term oral health issues if left unmanaged. These activities can cause tooth wear, jaw pain, and even conditions like migraines. Understanding parafunction and effective treatment, particularly with oral appliance therapy, is critical for dental professionals.

In his course, “Occlusion, Function, and Parafunction: Understanding the Dynamics of a Healthy Stomatagnathic System”, Dr. Steven D. Bender provides an in-depth look at parafunctional activities, how to diagnose them, and how to treat them effectively. The course allows dental professionals to earn 4 Continuing Education (CE) credits while offering practical knowledge for managing these common yet serious dental issues.

Below is a detailed breakdown of the course content and why it’s essential for dental professionals.

Chapter 1: Introduction to Occlusion and Parafunction

The opening chapter introduces the concept of occlusion—the way the upper and lower teeth meet during chewing, speaking, and other oral functions. Occlusion is a fundamental aspect of dentistry, as it affects every patient’s bite alignment, jaw function, and overall oral health.

Dr. Bender provides a clear definition of occlusion, citing widely accepted sources, including the Glossary of Prosthodontic Terms and Okeson’s description of occlusion as the basic static relationship of teeth. These definitions lay the foundation for understanding occlusal dynamics and the role they play in dental health.

The chapter also introduces parafunctional activities, which are behaviors outside the realm of normal oral function—activities such as lip and cheek chewing, nail biting, and teeth clenching. These activities, while seemingly harmless in the short term, can have profound effects on the teeth and the overall structure of the stomatagnathic system over time.

Chapter 2: Understanding Bruxism and Other Parafunctional Activities

The second chapter delves deeper into parafunction, with a specific focus on bruxism. Bruxism is defined as the excessive grinding or clenching of teeth and is categorized into two types: awake bruxism and sleep bruxism. While awake bruxism often involves clenching during the day, sleep bruxism is characterized by rhythmic or sustained jaw muscle contractions during rest.

Dr. Bender explains the prevalence of these activities, noting that:

• Around 20% of adults experience awake clenching,
• 8% of adults report grinding their teeth during sleep, often discovered through reports from sleep partners or roommates.

The chapter identifies the signs and symptoms of bruxism, including jaw stiffness, muscle hypertrophy, and tooth sensitivity. It also introduces the concept of Rhythmic Masticatory Muscle Activity (RMMA), which occurs in 60% of normal sleepers and can sometimes be confused with bruxism. The chapter highlights the importance of distinguishing between RMMA and actual sleep bruxism to provide accurate diagnosis and treatment.

Chapter 3: Signs, Symptoms, and Sequelae of Bruxism

This chapter focuses on the clinical signs and symptoms of parafunction and bruxism. Patients with sleep bruxism are more likely to experience jaw pain and movement limitations, with up to 65% reporting frequent headaches. The chapter also discusses the associated condition known as parotid-masseter syndrome, wherein patients experience pain when biting into food, which dissipates as the meal progresses.

The physical damage caused by parafunctional activities can be severe. Bruxism can generate forces as high as 975 pounds per square inch, leading to tooth wear, fractures, and tooth mobility. Muscle pain is also a common symptom, particularly after sustained clenching episodes that last between 20-40 seconds.

Additionally, radiographic changes in the mandibular condyles and flattening of the condyle are noted as common outcomes of severe bruxism. These changes are indicators of parafunctional activity and should be monitored closely.

The chapter concludes with a list of common signs and symptoms, including:

• Tooth wear
• Abfractions
• Jaw pain or stiffness
• Hypertrophy of the masseter and temporalis muscles
• Headaches and even neck and back pain

Chapter 4: The Migraine Connection

In this chapter, Dr. Bender explores the relationship between parafunctional activities and migraines. Migraine is a chronic neurological disorder, and bruxism has been identified as a contributing factor in many cases. The prevalence of migraine is higher in women (about 18%) than in men (6%), and it is considered one of the most disabling diseases by the World Health Organization.

The chapter explains how central sensitization and cortical spreading depression (CSD) contribute to migraine development. By stimulating the trigeminal vascular system, bruxism can trigger neurogenic inflammation, resulting in prolonged migraine attacks. Dental professionals are encouraged to consider the stomatagnathic system when evaluating patients with recurring migraines.

Chapter 5: Diagnosis of Parafunction and Migraine

This chapter provides a detailed guide to diagnosing parafunction and migraine. For parafunction, the diagnosis is primarily based on identifying characteristic symptoms such as jaw pain, muscle stiffness, and tooth wear. Other telltale signs include tongue scalloping and exostoses on the maxillary and mandibular arches.

A migraine diagnosis is based on specific criteria, including:

• A history of at least five attacks lasting 4-72 hours,
• Headache symptoms such as unilateral pain, pulsating sensation, and moderate-to-severe pain,
• Additional symptoms like nausea, photophobia, or phonophobia.

The chapter also advises caution when using imaging studies for diagnosis, recommending that imaging only be pursued in cases where patients show systemic symptoms, such as fever or weight loss, or in patients over 50 with new onset headaches.

Chapter 6: Management of Parafunction and Bruxism

In this key chapter, Dr. Bender presents the management strategies for bruxism and other parafunctional activities. While there is no curative treatment for bruxism, dental professionals can manage the condition using a combination of oral appliances, behavioral modification, and physical therapy.

The primary goal of treatment is to prevent damage to the teeth and reduce pain. The chapter highlights the use of oral appliances, which can protect the teeth from grinding and clenching forces. These appliances are also used as diagnostic tools to assess the extent of parafunctional activity.

Chapter 7: Oral Appliance Therapy

This chapter dives deep into the use of oral appliances to manage parafunction. There are several types of appliances available, including:

• Full-arch appliances: These cover either the maxillary or mandibular arches and are commonly used to treat severe grinders.
• Anterior coverage designs: These appliances cover only the anterior teeth, reducing muscle activity and minimizing occlusal forces.

The chapter introduces the NTI-tss (Nociceptive Trigeminal Inhibition Tension Suppression System), a device designed to reduce migraine pain, tension headaches, and temporomandibular joint disorders by limiting contact to the anterior teeth.

Dr. Bender also discusses the advantages and disadvantages of hard vs. soft appliances. Soft appliances are typically recommended for short-term use, while hard appliances offer long-term protection but may require more adjustments.

Chapter 8: Selecting and Monitoring Oral Appliances

The final chapter focuses on the selection and monitoring of oral appliances. Dental professionals must carefully choose the right appliance based on the patient’s needs and level of parafunctional activity. Regular follow-ups are essential to ensure that the appliance is working as intended and to adjust it if necessary.

Soft appliances may increase bruxism in some individuals, making hard acrylic appliances the preferred choice for long-term use. Additionally, mandibular appliances are recommended for patients with sleep apnea, as they can help improve airway patency during sleep.

What Is Parafunction in Dentistry?

Parafunction refers to activities within the stomatagnathic system that do not fall under normal functions such as chewing or speaking. Examples of parafunctional activities include nail biting, cheek chewing, and most notably, bruxism. Bruxism can be categorized into two types:

• Awake bruxism: This involves clenching or tapping of the teeth during the day, often linked to stress or concentration.
• Sleep bruxism: This is characterized by rhythmic muscle contractions of the jaw during sleep, often resulting in grinding sounds or tooth damage.

Dr. Bender notes that approximately 20% of adults experience awake bruxism, while 8% report grinding their teeth during sleep. Diagnosing and addressing these activities early can prevent long-term damage such as tooth fractures, wear, and even jaw disorders.

Bruxism: Signs, Symptoms, and Consequences

Bruxism is one of the most common parafunctional activities and has a range of recognizable symptoms:

• Morning jaw stiffness.
• Hypertrophy (enlargement) of the masseter and temporalis muscles.
• Sensitivity in the teeth.
• Tooth wear or fractures due to excessive grinding.

Sleep bruxism, in particular, can lead to severe consequences, including chronic jaw pain and headaches. Patients with bruxism are also 3 to 4 times more likely to experience jaw pain and movement limitations compared to those who do not grind their teeth.

The forces exerted during bruxism can reach 60% of maximum voluntary clenching, which can lead to severe tooth wear and damage to the temporomandibular joint (TMJ). In severe cases, radiographic changes in the jawbone may be visible, indicating chronic stress on the mandibular condyle.

Diagnosing Parafunction and Bruxism

Diagnosing bruxism and other parafunctional activities involves a thorough clinical evaluation. Dental professionals should look for signs such as:

• Tooth wear.
• Jaw stiffness and muscle pain.
• Scalloping on the tongue.
• Abfractions (small notches near the gum line).

Additionally, patients may report morning headaches or jaw pain upon waking. These symptoms, combined with a visual examination of the teeth and jaw, often point toward sleep bruxism as the underlying cause.

Dr. Bender emphasizes the importance of early diagnosis, as untreated bruxism can lead to more severe conditions, including chronic migraines and temporomandibular joint disorders (TMD).

The Migraine-Bruxism Connection

Bruxism is closely linked to migraines. Many patients with chronic migraines also exhibit parafunctional activity, especially sleep bruxism. Research has shown that bruxism can exacerbate migraines due to the involvement of the trigeminal nerve, which plays a significant role in the onset of migraine attacks.

The course explains how central sensitization and cortical spreading depression (CSD)—mechanisms involved in migraines—can be triggered by the stress and strain placed on the stomatagnathic system during bruxism. Patients with both bruxism and migraines require careful management to address both conditions simultaneously.

Managing Parafunction and Bruxism with Oral Appliance Therapy

Although there is no definitive cure for bruxism, oral appliance therapy is one of the most effective management strategies. These appliances, which are worn at night, help protect the teeth from grinding forces and alleviate jaw pain by reducing muscle activity.

There are several types of oral appliances available, including:

• Full-arch appliances: These cover either the upper or lower teeth, providing full protection against grinding.
• Anterior coverage appliances: These appliances, such as the NTI-tss (Nociceptive Trigeminal Inhibition Tension Suppression System), only cover the front teeth, helping to reduce clenching forces.

Each type of appliance has its advantages and disadvantages, and the choice of appliance depends on the patient’s specific needs. Dr. Bender’s course provides a comprehensive guide on how to select the appropriate appliance for each patient and how to monitor its effectiveness over time.

Selecting the Right Oral Appliance

Choosing the right oral appliance is crucial for effective management of parafunction and bruxism. Factors to consider include:

• Comfort: The appliance must be comfortable enough for the patient to wear consistently during sleep.
• Durability: Some appliances are designed for short-term use, while others are more durable for long-term management.
• Patient needs: For patients with severe grinding, a full-arch appliance may be necessary to protect all teeth. For those with migraines or tension headaches, an anterior appliance may be more effective.

Dr. Bender advises that regular follow-ups are necessary to ensure the appliance is functioning correctly and to adjust it as needed. Patients should also be educated on how to properly care for their appliances to maintain their effectiveness.

Conclusion

Occlusion, Function, and Parafunction by Dr. Steven D. Bender is a valuable resource for dental professionals seeking to expand their knowledge of parafunctional activities and their management. By understanding the dynamics of occlusion, bruxism, and oral appliance therapy, dental practitioners can significantly improve their patients’ oral health and quality of life.

For those looking to enhance their clinical expertise and earn 4 CE credits, this course offers an in-depth exploration of the key issues surrounding parafunction and provides practical solutions for managing these conditions in daily practice.