Occlusion clinical examination Flashcards
What are the indications for occlusal analysis?
Prosthodontic treatment
TMJ/Muscles assessment
Periodontal assessment
Mobility assessment
Functional discomfort
Mechanically failed restorative treatment
Bruxism diagnosis
Orthodontic treatment
Why is occlusal analysis done?
To replicate what the patient has in the mouth when mounting the models
Why is it important to get a good record of patient’s occlusion?
Provides a base line record
To monitor occlusal changes over time
To monitor disease development
To assess treatment implications
Which parameters are measured during a clinical examination of the articulatory apparatus?
E/O:
Masticatory muscles such as masseter, temporalis, medial pterygoid, cervical muscles and suprahyoid)
TMJ
I/O:
Masticatory muscles: lateral pterygoind, medial pterygoid
Dental occlusion
What should be investigated when examining the TMJ clinically?
Pain (chronic/acute)
Crepitus (clicking, crepitus)
Limited opening (locking, trismus)
Midline deviation and midline deflection
What causes trismus?
Can be caused by intraarticular causes and extraarticular causes (eg inflammation around joint following 3rd molar extraction)
How should TMD be treated?
Occlusal alteration has not been supported by evidence as a treatment for TMD. For this reason it is best to use conservative and reversible treatment to treat the problem.
Patient should be informed that prosthodontic treatment is not aimed to restore TMJ health.
How is the TMJ examined?
Palpate the TMJ capsules
Posterior palpation - index fingers in ears as patient opens and closes
Lateral palpation
Evaluate: Pain, joint sound, and disc movement
Mandibular movement examination (Smoothness and mandibular translation)
The interincisal space should be checked to see if there is good enough space for prosthodontic treatment (>40mm)
How can you know which side TMJ is affected?
The mandible always moves in the direction of the affected TMJ
What is midline deviation?
Mandible deviates then returns to the centered position. This indicates interference during condyle movement.
This is a sign of anterior disc displacement with reduction.
How is the masseter palpated?
Masseter is between the zygomatic arch and the mandible ramus. Palpate the muscle at rest and when clenching.
How is the temporalis muscle palpated?
Should be palpated anteriorly and posteriorly while the patient is clenching as well as where the masseter is to check the anterior fibers and the posterior fibers (retrusive and clinching parts)
How can the medial pterygoid be palpated?
Medial to the mandibular angle from outside the body or intraorally
Where does the medial pterygoid originate and insert?
Medial pterygoid plate onto ramus of the mandible
How are the suprahyoid muscles palpated?
Palpated near the chin underneath the mouth
What do the suprahyoid muscles do?
Mylohyoid, geniohyoid, digastric forming the floor of the mouth
Promote depression of the mandible
How is the lateral pterygoind muscle palpated?
Intraorally in the deepest depression within the buccal sulcus.
What do the 2 segments of the lateral pterygoid muscle connect?
Both originate on lateral pterygoid plate of the sphenoid
Upper head inserts onto articular disc
Lower head inserts onto neck of condyle
What role does the lateral pterygoid muscle have in allowing the jaw to protrude and relax?
When protruding the jaw the upper head is relaxed and the lower head pulls the jaw forward and downward.
When returning to normal posiiton the lower half relaxes and the upper half contracts in combination with the masseter and the temporalis muscle.
How are the muscles of mastication examined?
Degree of opening (should be >40mm)
Dynamic movements against resistance
What are the types of static occlusion measurements?
Centric occlusion (Contacts in this position) or centric or eccentric
Freedom in centric
Extent of posterior tooth support
Angle’s classification
Overbite and overjet
Cross bite
What is long centric?
Centric in patients with loss of tooth structure that leads to the jaw moving forward.
What is freedom in centric?
Sometimes centric occlusion is not the same as MIP position. The difference is the freedom in centric
What is investigated with dynamic occlusion?
Protrusion
Lateral movements (canine guidance and group function)
Interferences
What is investigated in dental occlusion?
Bruxism/clenching (worn teeth, muscle tenderness, muscle hypertrophy, cracked teeth, TMJ pain/locking/clicking)
Mobility (occlusal overlaod can cause wear in teeth splinting may be indicated)
Periodontitis (alteration of occlusion for periodontitis has not been shown to work)
Tooth stability (posterior tooth loss can result in drifting of maxillary incisors, over-eruption of unopposed teeth can occur, drifting/tilting is also possible)
Mechanical failure (poor restoration design or lack of occlusal stability)
Fremitus (Vibration when biting indicates deflective contacts)
What are the measured vertical dimensions?
Rest vertical dimension (RVD) (Muscles are in muscle tone)
Occlusal vertical dimension (OVD) (Muscles are contracted)
FWS (most patients are 3mm)
Why should freeway space be preserved?
If it isn’t preserved it can adversely affect phonation as well as making patient feel tired
What is the freeway space?
The distance between the incisors at rest
What are the criteria for ideal occlusion?
Mandibular stability (Bilateral contacts)
Axial occlusal load
During lateral excursions: No interference in the working side (Canine guidance/group function)
During lateral excursions: disocclusion in the non-working side
During protrusion: Disocclusion of posterior teeth
How is treatment of occlusion problems done?
Usually provided in conjunction with prosthodontic treatment.
Choice of which approach should be applied is made at the planning stage before any irreversible work.
What should treatment of occlusion problems depend on?
Complexity of treatment
Required modifications
Conditions of existing dentition/occlusion
Presence of occlusal abnormalities
What are the prosthodontic apporaches to occlusal issues?
Confirmative: Provision of restorations in harmony with existing jaw relationships according to the maximum intercuspation position.
Restorations must fit into the existing occlusal scheme. Following the restoration the occlusal contacts on other teeth are unaltered
Reorganized: Altering the existing occlusal scheme and establishing an ideal occlusion (or close to ideal) according to centric relation.
Requires additional stages of designing and establishing a new occlusion before providing a definitive prosthesis. Then confirmative treatment of new occlusion.
What are the advantages of using the confirmative approach?
Most cost effective restoration method with the least restorative intervention
Most commonly applied method in restorative dentistry
Applied for single restorations to multiple restorations
Easiest
Safest
Less likely to introduce problems for tooth periodontium muscles and TMJ
What are the indications for a reorganized approach to prosthodontics?
Increase in occlusal vertical dimension
Teeth significantly out of position
History of repeated restoration failure at the existing occlusion scheme
No posterior occlusal contacts at the desired vertical dimension.
