Occlusion sheet #8 - mohammed Okdeh!

Occlusal diseases
(Last for Dr Yara)
T
oday we will talk about the occlusal diseases that we may encounter during life.
- Signs of occlusal diseases can be easily observed in an early stage where the progression of the abnormality still can be intercepted, whereas symptoms may not be that obvious.
(A sign is a physical manifestation of illness, injury or disease, while a symptom is subjective. It’s defined as what the patient experiences about the illness, injury or disease)
- If treatment is not delayed until damage is severe, the complexity and course of treatment can be greatly reduced. This in particular what makes proper diagnosis of great importance in the process of treatment, the earlier the diagnosis the milder the symptoms and the less complex the treatment.
- In cases of early diagnosed lucky patient, the treatment could be limited to simple contouring of the teeth, selective grinding or splint treatment .
- Occlusal diseases are the most common destructive disorders of the dentition and they are a contributing factor of the eventual loss of teeth.
- They can be considered as a reason for needing an extensive treatment especially in the advanced stages of the disease.
-they also contribute to discomfort felt in one of the masticatory system structures or all of them (teeth, muscles and the TMJ),
- They contribute to instability in orthodontic treatment, because the presence of a deflective contact between teeth may ruin the whole orthodontic treatment, causing teeth to move from their proper positions
- Occlusal diseases are the most misdiagnosed dental disease that dentist are not aware of until sever damage is too obvious to be ignored. This misdiagnosis commonly leads to unnecessary endodontic treatment due to the continuous toothache – a common indication for endodontic treatment.

- “Lytle” was the first to introduce the term occlusal disease and defined it as the process resulting in noticeable loss or destruction of the occluding surfaces of the teeth.
- “Abrahamsen” defined different causes for destruction of tooth structure, and showed that how combined mechanisms of chemical effects could interact with occlusal overloads to intensify destruction of the tooth surface.
- The basic mechanism of tooth surface destruction is a combination of different forces; these forces are stress, friction and corrosion.
* Stress which is the outcome of the interaction between teeth results in compression and tension and this can produce microfracture and abfraction as a dental manifestation.
*Friction include abrasion from an exogenous material like hard food particles, nail biting, pens biting and attrition which results from endogenous factors like empty mouth bruxing and parafunction that end up with wear of the tooth surface.
*Corrosion is the result of chemical or electrochemical degradation of the teeth.
- These diseases are usually multifactorial, and the different mechanisms could overlap and interact to accelerate the structural damage and this particularly why the formation of teeth is considered to be multifactorial with occlusal overload being almost always the dominant factor.

- The following terms are very important to know, each one of them relates to a specific occlusal disease that has its own characteristics. we have to know them by heart:
* Attrition : is defined as wear due to tooth to tooth friction, this kind of wear result from bruxism and empty mouth parafunction. Where wear penetrate enamel to dentin the wear increases because of the increased organic content in dentin which leads to softer dentin.
- As we see in the picture, half of the crown is lost in the lower incisors due to attritional wear. Wear of the lower anterior teeth is one of the most common untreated problems. You can find this type of wear in most of your relatives especially those above 25 years old. Finding this type of wear is an indication for one of two causes:
 Deflective contact on posterior teeth that is caused by interferences between deflective inclines and centric relation, so when the patient closes in centric relation and due to the deflective contact the mandible slides forwards causing lower anterior teeth to collide with the upper teeth. This collision forces muscle to rub teeth against each other to make closure easier.
 The second cause of this disease is direct interferences between lower and upper anteriors that is most probably caused by an improper restoration or improper tooth inclination after orthodontic treatment.
*Abrasion is defined as wear due to friction between a tooth and an exogenous agent, this kind of wear comes from chewing of food, for example those who consume raw materials like fruits, vegetables or even have the bad habit of chewing tobacco are at an increased risk of developing abrasion. Excessive prolonged tooth brushing using a hard tooth brush is also an important cause of abrasion, so we always advise our patients to use medium type of tooth brushes. As we said before nail or pens biting or improper use of dental floss are all considered to contribute to the manifestations.


*Erosion is tooth surface loss due to, as stated above, chemical or electrochemical action which doesn’t include bacterial activity.
- Factors that cause erosion are either endogenous coming from the stomach or exogenous coming from consumed materials.
Endogenous factors may be one of the following:
1. Bulimic patients .
2. Patients with gastroesophageal reflux, if the reflux was to sever and reached the oral cavity the acidic and enzymatic content can cause teeth erosion.
3. Gingival crevicular fluid acidity also can cause erosion.
Exogenous erosion may be caused by any of the following :
1. Consumption of acidic food and juice, such as apple juice, lemon …etc.
2. Working in an environment that contains acidic vapor, like cars’ batteries workshops.
- this disease results from a combination of acid from fruit, abrasion from mulling fruit between end-to-end anterior contacts and attrition from bruxing resulting in invagination of the incisal enamel. But how to differentiate between erosion and other similar occlusal diseases?! This is known by that exposed dentine is not contacting opposing tooth structure, so borders of enamel are higher and well demarcated, because of the higher progress in dentine.

*Abfraction:
though the actual cause of abfraction is not known yet, it’s well established the role of occlusal overloads in causing fractures in the cervical third of teeth through bending under these forces which will lead eventually to chipping of surface enamel leaving a lesion (cavity) in that area.
- Numerous investigators have claimed that occlusal loading forces do cause flexure of the teeth that produces microfractures and structural loss of the cervical area. Acids penetrate these microcracks and undermine the tooth surfaces leaving them more susceptible to mechanical deformation.
- Some others suggest that these cracks have nothing to do with occlusal forces.
*splayed teeth:
The same type of mandibular deflection that causes wear problems can, in a different patient, force the upper anterior teeth forward. This disease is common in short lip patients because they lack any supporting forces to counteract the effect of this force. Splaying of teeth is a common sign of occlusal disease that should be diagnosed and treated early by eliminating the deflective interferences that forces the mandible forward. If splaying occur then orthodontic treatment is the treatment.
- Other signs of the same problem are fremitus and soreness of the anterior teeth in the early stage. Improperly contoured restorations that are too thick on the lingual of the upper anterior teeth or overcontoured lower restoration are causes of splaying.

*Destroyed dentition :
This is the worst condition that a patient might have. It results from not intercepting occlusal disease early. Signs of sever wear, fractured anterior teeth, and elongated alveolar processes are common. This elongation is due to the dento-alveolar compensation that compensate for vertical dimension loss. Treatment is so complex and results are compromised.

*Advanced occlusal disease:
This disease results from a combination of attritional wear and moved teeth. So many factors combine to make occlusal disease more advanced and thus harder to be treated.

*Anterior guidance attrition:
This occurs when anterior teeth that either interfere with centric relation closure or interfere with functional jaw movement patterns develop early signs of attritional wear of the lingual enamel on upper anterior teeth. This type of occlusal disease too often goes undiagnosed until the incisal edge become so thin they start to chip and fracture.

*Sensitive teeth:
One of the most missed diagnoses is failure to recognize that a common cause of hypersensitivity is occlusal overload. This sensitivity can result from pulpal hyperemia or from effects of non-cervical cracks.

*Sore teeth:
Compression of periodontal ligaments can be combined with pulpal hyperemia to cause considerable soreness or pain on biting. If empty mouth clenching causes any discomfort in a tooth, it is an indication that the sore tooth is in occlusal interference.
-The simple clench test is the best way to diagnose this disease, this diagnosis will reduce unnecessary endodontic treatment chances.
* Hypermobility:
An early sign of occlusal disease is tooth Hypermobility. It can result in widened periodontal space and greater susceptibility to periodontal disease. All loose teeth should be evaluated to see if a deflective contact or occlusal overload is a factor.

* Split teeth and fractured cusps:
Sometimes occlusal overloads may result in splitting of tooth structure. You can notice fracture lines that routinely develop when a cusp incline interferes with strong occlusal forces. This commonly precedes cusp fracture or split tooth.


*Painful musculature
Soreness in muscles, in temporalis, in masseter, or in the medial pterygoid is an example of this disease. So it is important to understand that diagnosis and treatment of all forms of occlusal disharmony are dependent on the clinician’s knowledge of the total masticatory system design and function.
That’s all for today


God bless you
Occlusion, 8th lecture
Mohammed A. Okdeh