The Importance of Occlusion and Occlusal Diagnosis in Restorative Dentistry
Ceramic restorations are at an increased risk when a patient suffers from a traumatic occlusion combined with a parafunctional activity (occlusal disease). In fact, longevity studies point to the decrease in durability of ceramic restorations in patients with parafunctional habits (Figure 12.1a,b) . The reality of the shorter durability of bonded ceramic restoration should be tempered with the reality that all restorations and the teeth restored, including porcelain-fused-to-metal and gold crowns, will have shorter durability and other problems when the patient has a severely traumatic occlusion and parafunctional activity (Figure 12.2a,b) . Because of the fear of fractured restorations, many contraindicate partial coverage ceramic restoration, thus suggesting the use of more aggressive procedures such as full crowns of any type, including full zirconia crowns [3,4,5,6]. Ultimately, parafunctional activity combined with a traumatic bite (occlusal disease) is the reason for restoration failures , and good occlusal management can lead to success even in difficult cases (Figure 12.3a–h).
If unbreakable restorations are used without proper occlusal management, the unbreakable restoration will only transfer the forces and the damage into deeper tissues, or create other problems. The uncontrolled occlusal forces are great and will be expressed in many other ways, such as loose restoration, loose teeth, pain and sensitivity, tooth fractures at the neck or root level (Figure 12.4a,b), periodontal damage, headaches, migraines, and others. The following is a clinical example of how improper occlusal management can lead to restorative failure (Figure 12.5a–c). Figure 12.5a shows the gold onlay of a patient who suffered from postoperative pain and sensitivity for almost 2 years. She was scheduled for root canal treatment in the next few days. After differential diagnosis, occlusal trauma was considered to be a possible etiology for the pain, and within 2 days of a bite adjustment, the tooth stopped hurting permanently. Although the restoration did not break and it had great margins, the improper occlusal management led to patient dissatisfaction, long-term discomfort and almost an unnecessary endodontic procedure. Restorative success is far more than a restoration which does not break. Restorative success will encompass leaving the teeth needing repair or restoration in a healthy state, free of pulpal damage, and periodontal disease, and a patient who is satisfied with the esthetics of the restoration.
Understanding the great importance of occlusion and occlusal management improves the quality of dentistry, and the health of patients because:
- It allows better differential diagnosis in complicated cases, because undiagnosed occlusal problems are responsible for many catastrophic treatment decisions and results.
- It encourages healthier dentistry, more supragingival minimally invasive dentistry, because the fear of fractured restorations forces the dentist to cut crowns, rather than using partial coverage.
- It permits better, more comprehensive treatment for patients. Fear of fractures or failure prevents the dentist from undertaking single-tooth dentistry and encourages them to shy away from more comprehensive cases.
- Ultimately, it provides a healthier dental life for patients with occlusal disease. Early diagnosis and minimally invasive management permits patients to have a more satisfying, healthier dental life.
Attention to occlusion goes beyond restorative success, as occlusion is one of the leading causes of tooth loss and is also one of the three main enemies of human dentition, alongside caries and periodontal disease . An excellent example is shown in the comparative photographs in Figures 12.6 and 12.7 of two patients, both in their early thirties, which show the devastating effect of occlusal disease. The patients are of similar age, both with good home care, free of caries and periodontal disease, but one has normal-looking dentition and the other has fractures, chips, abfractions and excessive incisal wear. There are similar examples in every practice. In this way, patients’ dentition is compromised by occlusal disease, and it must be treated. Dentistry’s goal is to help patients to keep their teeth for life, and occlusal disease can compromise this goal, inasmuch as caries and periodontal disease. Excessive incisal wear, fractures and other signs of occlusal disease are not an inevitable result of aging (Figure 12.8).
Occlusion and the treatment of occlusal disease is completely vital to dentistry. This is because everything that a dentist does affects the patient’s occlusion, and in turn everything a dentist does is affected by the patient’s occlusion (Figure 12.9). Even so, millions of patients with severe occlusal disease go untreated . A primary obstacle for managing occlusal disease is the patient’s absolute disinterest in their bite and refusal to accept grinding, clenching, or the importance of wearing a night guard. This leads to the question: whose fault is it that patients are so ignorant of the very negative effects of occlusal disease? Yes, the dental community. The problem is the failure to explain to the patient how occlusal disease is not just wear. There are, however, other deeper and more damaging signs and symptoms occurring beneath the visible wear. Another major obstacle in implementing occlusal diagnosis and management is the erroneous idea that extensive rehabilitation is the best way of managing worn dentition. The idea that function follows form instigates full rehabilitations. Occlusal management can and should be minimally invasive.
The dictionary definition of disease is “an impairment of the normal state of the living animal or plant body or one of its parts that interrupts or modifies the performance of the vital functions, is typically manifested by distinguishing signs and symptoms, and is a response to environmental factors, to specific infective agents, to inherent defects of the organism (as genetic anomalies), or to combinations of these factors” . Negative effects of occlusion have typically been referred to as “problems” or “conditions”.Based on the definition above, however, disease is the more appropriate term, giving the term “occlusal disease”. The etiology of occlusal disease is a combination of inherent defects or malocclusion (traumatic bite), environmental factors or maladjusted restorations, and abnormal masticatory parafunctional activities, which will lead to degeneration and dysfunction of the masticatory system, expressed in signs and symptoms. For occlusal disease to exist, both conditions must coexist. Because a perfectly balanced, atraumatic bite does not usually exist in nature, and parafunctional activities are uncontrollable central nervous system activities that can be exacerbated by stress and certain drugs, it can be said that occlusal disease is extremely common, and it is also a chronic, incurable disease [11,12]. A more appropriate definition would be; “Occlusal disease is a chronic destructive process evident in any part of the masticatory apparatus (joint, muscles, periodontium or teeth), as a consequence of occlusal disharmony and parafunction. It has specific signs and symptoms and as any chronic disease it cannot be cured, but it can be managed” .
It is important to differentiate temporomandibular joint disease (TMD) from occlusal disease. Occlusal disease is the damage caused by the combination of parafunctional activity and a traumatic occlusion, while TMD is associated with internal damage of the joint. Occlusion and the management of occlusal disease is more mechanical, with the goal of harmonizing the occlusion based on well-known functional principles, as well as protecting the masticatory structures from the damage from parafunctional habits with appliances. Early diagnosis and management of occlusion is of great importance to any dentist, as occlusion affects every aspect of dental treatment. While all dentists need to be experts in occlusion, it is also important to be able to diagnose when there is true temporomandibular joint damage. The treatment of TMD is more complicated, because it is a joint condition and as such requires a more medical approach, as would any other joint. The restorative clinician can choose to train in the treatment of TMD or can choose to refer such cases to other experts or specialists.
A crucial step in implementing occlusal management is patient education. Once the patient accepts the importance of occlusal health, appropriate occlusal therapy will be a regular part of their oral health maintenance (Figure 12.10). Using the word “disease” instead of “condition,” “wear,” or “aging” is important in patient education. The latter terms lead the patient to perceive occlusal problems as a natural consequence of wear or aging. The first step in educating and managing occlusal disease is the implementation of a simple, yet effective system for accomplishing early diagnosis. It is also important to evaluate the severity of the disease (signs and symptoms) to present the most minimally invasive management possible, appropriate to the severity of the condition. Diagnosis using the seven signs and symptoms of occlusal disease makes this possible.
Regardless of what we choose to call occlusal problems, it is paramount to have a simple, methodical and fast way of diagnosing occlusal problems. Traditionally, diagnosing occlusal problems has been via a mounted cast and extensive interviews. It is virtually impossible and impractical for most dental practices to mount a cast on each patient, and it has been an obstacle in the implementation of routine occlusal diagnosis. Diagnosis of occlusal disease should not be limited to patients with severely damaged teeth, nor should the ability to diagnose be limited to certain dentists. Early diagnosis can prevent many problems from occurring (Figure 12.11) or worsening, so it is vital that dentists have a simple way of quickly and efficiently implementing occlusal examination and diagnosis into their routine examinations.
The Occlusal Disease Management System [7,13] is incremental, based on severity, and incorporates patients’ willingness to accept diagnosis and treatment. It allows even the busiest of dentists to incorporate occlusal diagnosis and therapy for every patient, as it only takes 3 minutes to do a simple occlusal diagnosis. Knowing the seven signs and symptoms of occlusal disease (Box 12.1) is part of the first stage, aiding in diagnosis . Every patient in the practice must have an occlusal examination as part of a comprehensive examination, as well as at periodic examinations; this is Stage 1. Stage 2 is reserved for patients with moderate to severe signs and symptoms or those who wish esthetic rehabilitations or are in need of extensive restorative dentistry and are motivated to pay for a complete occlusal analysis with mounted casts (see Chapter 13). Stage 3 is when the patient is diagnosed with true joint disease or TMD, which usually means referral to a specialist or treatment if the clinician is trained to treat those cases.