Examination Of Occlusion Flashcards
What components make up the articulatory system?
- TMJ
- Muscles of mastication
- Occlusion (tooth surfaces contact during jaw movement)
What are the basic movements of the TMJ?
- Hinge - initial rotation
- Gliding - sliding from Mandibular fossa onto articulate tubercle (translation)
What happens in a hinge movement?
Head of mandible rotates around transverse axis
What happens in a gliding movement
Mandible head leaves Mandibular fossa and slides forwards onto articular tubercle
- Translation
What are muscles of mastication innervated by?
CNV3 - Trigeminal Mandibular division
What are functional movements of the TMJ?
- Protrusion
- Retrusion
- Elevation
- Depression
- Lateral excursion
How is the TMJ examined in E/O?
- Palpitation of pre-Auricular area (outside)
- Palpation of intra-Auricular area (inside)
What is looked for in TMJ examination?
- Sounds e.g. clicking
- Abnormal movement of joint
How are the muscles of mastication innervated?
Mandibular division of trigeminal merve (CNV3)
What muscles of mastication can’t be examined?
- Lateral pterygoid
- Medial Pterygoid
What is felt for when examining muscles of mastication?
- Tenderness - this can be caused by overworking (Hypotrophy) e.g from clenching jaw
- Muscle spasms
What movement does the temporalis do?
- Closes jaw
- Retracts jaw
What movement does the masster do?
Closes jaw
Retracts jaw
What is occlusion?
This is where the tooth surface come into contact when the jaw is closed or moving
What is ICP?
Intercuspal position
- this is position of maximum intercuspation of teeth
What is occlusal contacts?
Where cusps meet each other in stable forces e.g. cusp lies in lossa so there is no excess force on the tooth, when jaw is out of line excess force can be applied to sides of tooth causing them to break
What is protrusive excursion?
This is when the incisal teeth are touching, the mandible is moved anteriorly and posterior teeth generally aren’t in contact
How does lateral excursion work?
This is when the jaw moves to the side
e.g. when the jaw moves right the right side is called the “working” side and then left is the non working side
What teeth occlude for lateral excursion?
Most commonly canines touch and also lateral incisors (on working side)
What is articulating paper held in?
Millers forceps
What is the ideal occlusion?
- Even contacts for ICP
- Anterior guidance for anterior teeth
- No contact on non working side for lateral excursion
- Disoclusion of posterior teeth when there is excursion
What is the conformative approach to dentistry?
This is the idea of not changing the natural occlusion pattern too much so it Belen harmoniously with existing pattern
What are the reference point when it comes to classifying incisors?
Upper incisor - Singulum
Lower incisor - Incisal edge
What is a class 1 incisor?
- This is when the upper incisal edge occludes or lies slightly below cingulum
What is a class 2 div 1 incisor?
This is called an overjet
- The lower incisor is most posterior and incisal edge lies posterior to the upper incisal cingulum
What is a class 2 div 2 incisor?
This is called an overbite
The lower incisor edge lies posterior to the cingulum of upper incisor
- The upper incisors over the lower incisors
What is a class 3 incisor?
This is when the lower incisor edge is anterior, or occludes anterior to the cingulum of the upper incisors
- can have an overjet but this is called negative as the lower incisor is further in front
What is are centrelines?
This is a line drawn to see the symmetry of the jaw and see if mandible and maxilla are lined up
What is the reference point for molar classification?
Upper 6 - mesio-buccal cusp
Lower 6 - mesio-buccal groove
What is a class 1 molar?
This is when the mesio-buccal cusp lies/ occludes with the mesio-buccal groove
What are class 2 molars?
This is when the mesio-buccal cusp is more anterior to the mesiobuccal groove
- Upper jaw is anterior
What is a class 3 molar?
This is when the messio-buccal cusps is more posterior to the mesiobuccal groove
- lower jaw in more anterior
What is the RCP?
This is retruded contact position, is the position when thr condyle are in their most retruded position and teeth and in contact
What do pateint have to do to get into the RCP position?
- Open mouth wide
- Curl tongue to the roof of the mouth
- Close teeth together till first tooth contact
What is the freeway space?
This is the natural gap between teeth when the jaw is resting around 2-4mm
When should upper and lower teeth be in contact?
- Chewing
- Swallowing
