Operative Dentistry Flashcards
in terms of occlusion what are the 2 major mandibular movements
ROTATION
TRANSLOCATION (lateral translation)
describe the rotation movement in the mandible
occurs when the mandible makes a HINGE movement ( the condyle hinges within the articular fossa)
describe the translation movement in the mandible
Condyle and disc translate anteriorly as lateral pterygoid contracts
what does Posselt’s envelope of mandibular movement describe
border movements of the mandible in the Sagittal Plane
what is ICP
intercuspal position
- it is tooth position regardless of condylar position
- there is max interdigitation of the tooth
- can be called centric occlusion
describe protrusion (in Posselt’s envelope)
- condyle moves forwards and downwards on articular eminence
- only incisors +/- canines touch
at what point in Posselt’s envelope does it describe full translation of the condyle over the articular eminence
maximum opening
what is the Bennet Movement
bodily shift of the mandible at the working side
what is the Bennet angle
the path of the non working condyle in the horizontal plane during lateral excursion
In a relaxed upright patient what is the average distance in millimetres between ICP and resting position
2-3 mm
What TWO records are required for mounting casts on a semi adjustable or average value articulator?
Upper and lower impression
Facebow
a jaw registration
What is the average value of the sagittal condylar guidance angle which may be used on an articulator
set at 30degrees
What is the average value of the Bennet angle set at on an articulator
15 degrees
what are extrinsic causes of tooth colouration
smoking
tannins (tea, coffee, red wine)
chromogenic bacteria
chlorhexidine
iron supplements
what are intrinsic causes of tooth colouration
fluorosis
tetracycline
non-vitality
physiological
dental materials e.g. amalgam
porphyria (red primary teeth)
cystic fibrosis (grey)
Thalassemia, sickle cell anaemia
hyperbilirubinaemia
