Final Flashcards
What type of movements does an articulator imitate?
MN!
Is an occlusal exam alone diagnostic of a disorder?
NO! NEED ARTICULATOR. Improve visualization of both static and functional interrelationships of teeth. Allows lingual examination of pts occlusion.
What are the types of articulators?
Non-adjustable, semi adjustable, fully adjustable.
What is the general rule of accuracy of articulators?
More adjustable, more accurate.
What did Bonwill do?
Equilateral triangle hypothesis. Arbitrary axis to orient casts. Apply theories of MN movement. Condyle centers for lateral, opening and closing.
Average Axis Facebow
A facebow that relates the MX teeth to the average location of the transverse horizontal axis.
What is an Ear Bow?
A face bow. Indexes to the external auditory meatus and registers the relation of the MX dental arch to the external auditory meatus and a horizontal reference plane. Used to transfer the MX cast to the articulator. Provides an avg anatomic dimension between the external auditory meatus and the transverse horizontal axis of the MN.
What is are the advantages and disadvantages of a non-adjustable articulator?
It is a “cast relator” Simple, inexpensive. But, limited accuracy in duplication of MN movements.
What are the advantages of a semi-adjustable articulator?
Allows 3 types of adjustments for more accurate reproduction of the condyles.
What are the 3 adjustments of a semi-adjustable articulator?
Condylar inclination, lateral translation movement (bennett angle) inter condylar distance.
What are the determinants of MN movement in a normal joint?
The farther anterior a tooth is located, the less influence the TMJ and greater the influence of the anterior guidance.
What do do lateral interocclusal record program?
Capture the exact position of the teeth and condyles during lateral movement. Condylar inclination and bennett angle are adjusted to duplicate this condylar position.
Condylar Inclination
Angle at which the condyle descends along the articular eminence.
Progressive (Bennett) Angle
The angle formed by the sagittal plane and the path of the non-working condyle during lateral movement of the MN as viewed in the horizontal plane.
Movement of the orbiting (non-working) condyle. Correct groove placement and fossa width.
Intercondylar Distance
The distance between the rotational centers of the condyles.
What does intercondylar distance effect?
Effects mediotrusive and laterotrusive pathways of posterior cusps over opposing occlusal surfaces.
What are the 3 points used to orient the MX cast?
Rt condyle, Lt condyle, anterior point.
Purpose of face bow?
Triangulates AP and laterally. Orients the MX cast in 3 dimensions to the articular using 3 pts. Rt condyle, Lt condyle and anterior pt.
What are the advantages and disadvantages of a fully adjustable articulator?
Advantages: Most precise condylar movement.
Disadvantages: Cost, time needed to properly adjust.
Semi vs. Fully adjustable condylar inclination
Semi is capable of producing a protrusive condylar movement in a straight line only. Fully is capable of duplicating the angle and curvature of the protrusive condylar movement.
Semi vs. fully orbiting condyle
Semi can record the progressive angle movement in a straight line only. Unable to reproduce any immediate lateral sideshift. Fully can duplicate the exact pathway taken by the condyle in laterotrusive movement and any immediate lateral side shift.
Semi vs. fully Rotating condyle?
Semi, no adjustment possible. Fully is capable of duplicating the lateral, superior, inferior, forward or backwards sideshift as the working condyle rotates.
Semi vs. Fully intercondylar distance
Semi has small, medium and large. Fully can exactly match the distance between condyles.
Immediate MN lateral translation
Bennett movement. It is the movement of the rotating (working) condyle. Influences fossa depth, cusp height, ridge and groove direction of posterior teeth.
What are the procedures required for the fully adjustable articulator?
Exact hinge axis location. Pantographic reading. CR record.
Pantographic recording
Identifies the exact MN movements. Protrusive and laterotrusive. Determined by pts condyles moving against the discs and fossae. Acts as face-bow transfer
The more adjustable an articulator is…..
Better accuracy, higher expense, more time transferring info from pt to articulator, less time adjusting intraorally, need to determine which articulator is right for treatment.
What do you use to select an articulator?
Characteristics of pts occlusion. Extent of the restorative procedures. Limitation of articulators. Skillz of the clinician.
When is a fully indicated?
Complex full mouth reconstruction. Cases with OVD changes of greater than 2 mm. NEED ADVANCED TRAINING.
MI
A closed contacting and static relationship of the teeth.
What is the total contacting area of teeth?
May not exceed 4 mm2
What provides consistency to occluding parts?
Elevations and depressions. Cusps and fossas. Ridges and grooves.
Determinants of occlusal morphology?
Recognized that patterns of occlusal surfaces are resultants of patterns of MN movement.
Is occlusion a primary factor in perio disease?
No! But it can be a severe secondary factor.
What does a proper occlusal analysis require?
Accurate diagnostic casts. CR mounting of the casts on a semi-adjustable articulator. Condyle controls set by lateral interocclusal records or by matching wear facets on teeth.
What are the cusp to fossa occlusion advantages?
Forces in line with the long axis of teeth. Eliminates the “plunger cusp” effect. Greater stability. Less tendency towards tooth mobility.
On the MX vs MN which way do the lines point?
Out on the MX in on the MN
What are the elevations?
Cusp tips, marginal ridges, triangular ridges, central ridges (buccal/lingual contours), supplemental ridges.
What are the depressions?
Supplemental grooves, developmental grooves, fossas.
What cusps are the stamp cusps?
Upper lingual and lower buccal.
What cusps are the shearing cusps?
Uppper buccal and lower lingual.
What is a unit of occlusion?
A cusp and a fossa.
What are the A contacts?
Non working cusps of the MX teeth occlude with the working cusps of the MN teeth.
What are the B contacts?
Working cusps of the MX teeth occlude with the working cusps of the MN teeth. Most difficult to attain and maintain.