Occlusion and Restorative Dentistry Flashcards
capsule of TMJ
fibrous membrane that surrounds the joint and attaches to the articular eminence, articular disk and neck of the condyle
articular disc of TMJ
fibrous extension of joint capsule that runs between the two articulating surfaces of the joint and divides the joint into 2 sections (superior and inferior) each with their own synovial membrane
does the articular disc have a nerve and blood supply
no
how is the articular disc attached to the condyle
attached laterally and medially to the condyle by the collateral ligaments
where does the anterior and posterior aspects of the articular disc attach to
anterior - superior head of lateral pterygoid
posterior - mandibular fossa
what is the posterior portion of the articular disc known as and discuss its vascular and nervous supply
retrodiscal tissue
highly vascularised and highly innervated - due to this it is a major contributor to pain in TMJD
what are the two main types of mandibular movement in terms of occlusion
rotation and translation
mandibular movement - rotation
occurs when there is a very small amount of mouth opening - up to 20mm
condyle and disc remain within articular fossa
a ‘hinge’ like movement around an imaginary line known as the terminal hinge axis
purpose of a face bow
records the relationship of the maxilla to the terminal hinge axis of rotation of the mandible
allows for the maxillary cast to be placed at an equivalent relationship on the articulator
mandibular movements - translation
condyle and disc translate anteriorly as lateral pterygoid contracts. movement is towards the articular eminence then downwards along the incline of eminence
what is the working side when talking about lateral translation of the mandible
side the mandible moves towards
what is lateral translation of the mandible also known as
Bennet movement
Bennet angle
angle formed by the sagittal plane and the path of the non working mandibular condyle during lateral movement when viewed in the horizontal plane
discuss the most common TMJ disorder - anterior displacement
Articular disc displaced anteriorly so retrodiscal tissue is pulled forward between the condyle and mandibular fossa. This can be very painful due to it being highly innervated.
In order for mouth to fully open in these circumstances condyle must jump over back end of articular disc which might result in a clicking or popping sound - the same would be heard upon closure as it jumps back down
Over time sorts itself out as retrodiscal tissue becomes scar tissue and functions almost identically to the original articular disc
