Use LEFT and RIGHT arrow keys to navigate between flashcards;
Use UP and DOWN arrow keys to flip the card;
H to show hint;
A reads text to speech;
57 Cards in this Set
- Front
- Back
|
Condylar poles
|
The medial pole is wider than the lateral
|
|
|
What is the transverse horizontal axis
|
line between the two condyles
|
|
|
Maximal Intercuspation (MI)
|
occurs when the jaws are closed in a position that produces maximal stable contact between the occluding surfaces of the maxillary and mandibular teeth.
|
|
|
Centric Occlusion (CO)
|
refers to the relationship of the mandible to the maxilla when the teeth are in MI (Maximum Intercuspation) irrespective of the position or alignment of the Condylar Disc assemblies. This is also referred to as Acquired Centric.
|
|
|
Centric Relation (CR)
|
is the relationship of the Mandible to the Maxilla with properly aligned condyle-disc assembly in the most SUPERIOR (highest) position against the eminentia, irrespective of tooth position or vertical dimension.
|
|
|
What type of joint is the TMJ
|
GinglymoarthrodialJoint
|
|
|
What is the function of ligaments
|
limit and restrict mandibular movement, not meant to stretch
|
|
|
Functional ligaments
|
–Collateral (discal) ligaments –Capsular ligaments –Temporomandibularligaments
|
|
|
Accesory ligaments
|
Sphenomandibularligaments –Stylomandibular ligaments
|
|
|
Function of the collateral (discal) ligaments
|
attach disc to condyle, create sup and inf joint space, allow disc to move passively w/condyle There is medial and lateral discal ligament. |
|
|
Function of the capsular ligaments
|
Encircle the joint, attach sup to temporal bone and inf to neck of condyle, resist separation of articular surfaces, encompass joint, retaining the synovial fluid
|
|
|
What are the two portions of the temporomandibular ligaments and what is their function
|
outer oblique portion and inner horizontal portion Limit rotational opening, protect retrodiscal tissue from trauma, protect lateral pterygoid muscle from over lengthening |
|
|
Two movements of TMJ
|
Rotation: occurs primarily in inferior joint cavity, which has a tight joint capsule Translation: occurs in the superior joint cavity which has a loose capsule |
|
|
Where is the outer oblique portion located?
|
OOP extends from outer surface of articular tubercle and zygomatic process posteroinferiorly to the outer surface of the condylar neck
|
|
|
Where is the IHP located
|
from outer surface of articular tubercle and zygomatic process posteriorly and horizontally to lateral pole of condyle and posterior part of articular disc
|
|
|
What are the retrodiscal tissues and what are they made up of?
|
superior retrodiscal lamina (elastic); IRL, inferior retrodiscal lamina (collagenous); ACL, anterior capsular ligament (collagenous)
|
|
|
What are the muscles of the TMJ innervated by?
|
Mandibular division of trigeminal nerve (V3)
|
|
|
Sphenomandibular
|
Extends from spine of sphenoid to lingulaof mn No known fxnrole |
|
|
Stylomandibular
|
Extends from styloidprocess to medial border of angle of mn May limit excessive protrusion |
|
|
What are the muscles that close the jaw?
|
Masseter, temporalis, and medial pterygoid
|
|
|
What are the muscles that open the jaw?
|
Lateral pterygoid, digastric and geniohyoid
|
|
|
Masseter
|
Elevates and protrudes Zygomatic arch angle of the ramus |
|
|
Temporalis
|
Temporal fossa, coronoid process & anterior border of the ascending ramus Elevates… various portions can contract making this an important muscle in positioning the mandible -important for closing, positioning and retraction |
|
|
Medial Pterygoid
|
Pterygoid fossato medial surface of the mandibular angle forming a sling w/ Masseter elevates the mandible Unilateral contraction mediotrusive movement |
|
|
Lateral ptergyogoid
|
Originates from two heads – Superior head (sphenoid bone) – Inferior head (lateral pterygoid plate) ▪ Inserts on the neck of the mn Pulls condyle forward and medially opening the jaw and causing medial rotation and medial excursion on the same side |
|
|
Simple hinge articulator
|
Only capable of hinging/rotation
|
|
|
Semi-Adjustable Articulator
|
closer approximation of anatomical distance b/w axis of rotation and the teeth -> less error (crowns, FPDs) Capable of adjusting some jaw movements like: Protrusive and Lateral movement receives a face-bow transfer Two types: arcon and non-arcon |
|
|
Arcon
|
Mimics the natural joint with the condyle part of The lower member of the articulator
|
|
|
Non-Arcon
|
Reverse configuration of the natural joint Condyle part of the upper member of the articulator
|
|
|
One issue with a small articulators is
|
a smaller radius closure path, which results in premature contact at the clinical try-in between the premolars during hinge closure since the radius of the arc affects the likelihood of interferences
|
|
|
Fully Adjustable Articulator
|
Reproduces entire character of border movements Immediate & progressive lateral translation Curvature & direction of condylar inclination Adjustable intercondylar distance
|
|
|
When putting casts into the articulator where should there be contact?
|
•Second molarsmust be in contact, bilaterally. •In addition, ideally bilateral contact of the first premolars
|
|
|
Rotation Around the Horizontal Axis
|
Both condyles are in RCP can rotate around Horizontal axis Open close motion First 20-25mm rotation, then combines w/translation |
|
|
Rotation Around the Frontal Axis
|
-one condyle moves anteriorly out of RCP while opposite condyle stays in RCP -does not naturally occur: moving condyle forced to slide anteriorly and inferiorly down the articular eminence |
|
|
Mandibular movement as the mouth opens (more advanced description not really flashcard, just for info)
|
The mandible initially opens with a hinge movement about a horizontal axis known as the retruded axis or terminal hinge axis (THA), with the condyles in the retruded position (RP) (centric relation).This is described as the most superior position of the condyles in their fossae. The RP is clinically reproducible in both dentate and edentulous patients. lWhen the mandible rotates around this axis the first tooth contact occurs – the retruded contact position (RCP).l The mandible then slides forwards bringing the teeth into maximum intercuspation – the intercuspal position (ICP) (centric occlusion).
|
|
|
Rotation Around the Sagittal Axis
|
-one condyle moves inferiorly out of RCP while the other remains in RCP -Not naturally occurring: ligaments restrict this motion |
|
|
Rotation occurs in
|
in the inferior joint cavity (b/w the superior surface of the condyle and the inferior surface of the articular disc).
|
|
|
Translation occurs
|
in the superior joint cavity (b/w the superior surface of the articular disc and the inferior surface of the articular eminence).
|
|
|
Protrusion
|
A position of the mandible anterior to centric relation.
|
|
|
Lateral Excursions
|
Movement to the side basically: -rotating condyle is working -orbiting condyle is non-working/ balancing |
|
|
Centric Relation (CR)
|
The maxillomandibularrelationship in which the condyles articulate with the thinnest avascular portion of their respective discs with the complex in the most anterior-superior position against the shapes of the articular eminences. This position is independent of tooth contact (doesn't matter if the patient has teeth or not, since it is a stable joint position)
|
|
|
Centric Occlusion (CO)
|
▪The occlusion of opposing teeth when the mandible is in centric relation. This may or may not coincide with the maximal intercuspalposition
|
|
|
Maximal Intercuspal Position (MIP)
|
The complete intercuspationof the opposing teeth independent of condylar position, sometimes referred to as the best fit of the teeth regardless of the condylar position ▪MIP = MI (maximum intercuspation)= ICP (intercuspal position) = IP (intercuspal position) |
|
|
Is CO=MI?
|
Generally no, In approximately 90% of the population CO≠MI.Slide 1.25 ±1 mm from CO to MI
|
|
|
Bilaterally Balanced Articulation
|
All teeth contact in centric and eccentric positions to promote denture stability In dentate patients you get inceased wear, periodontal breakdown and TMD |
|
|
How do group function occlusion and mutually protected occlusion affect the working side and the non-working side?
|
The working side discludes (doesn't include) the non-working side
|
|
|
Working side
|
same side as the rotating condyle. The side toward which the mandible moves.
|
|
|
Non-working side
|
–same side as the orbiting condyle. The side moving toward the midline.
|
|
|
Group function occlusion
|
-unilaterally balanced articulation (all teeth must contact in unison) -No excursive contacts on the non-working side -Posterior teeth contact on the working side ▪ Simultaneous contact of several teeth acting as a group to distribute occlusal forces |
|
|
Mutually Protected Occlusion
|
▪ Anterior guidance during excursive movements ▪ “Canine protected occlusion” ▪ No posterior occlusal contacts in lateral or protrusive movements ▪ None or light contact of anterior teeth when posterior teeth are in MI
|
|
|
Optimum Occlusion
|
▪ “Occlusion which requires a minimum of adaptation by the patient.” ▪ Uniform contact of all teeth when the condylesare in CR (MI=CO) ▪ Anterior guidance is in harmony with the patients border movements (mandibular movement at the limits dictated by anatomical structures ) ▪ Posterior tooth contacts are directed down the long axis of the tooth ▪ No contact of posterior teeth in protrusion ▪ No contact of posterior teeth in lateral excursions |
|
|
How is group function occlusion different from mutually protected occlusion?
|
Group function occlusion distributes lateral stresses to a group of teeth, rather than a single tooth.
|
|
|
When is anterior guidance not possible?
|
– Class 2 occlusion with extreme Horizontal Overlap – Class 3 occlusion with all mandibular anterior teeth outside of the maxillary anterior teeth – Some end-to-end bites – Anterior open bite – In these scenarios, the anterior teeth do not couple. Coupling is contact of the anterior teeth in complete closure.
|
|
|
Centric Interference
|
– Retrusive Contact – (Closure Interference)
|
|
|
Working interference
|
Premature contact on the working side during lateral mandibular movement. – LaterotrusiveContact |
|
|
Nonworking Interference
|
– Mediotrusive Contact – (Balancing Interference) Premature contact on the nonworking side during lateral mandibular movement. |
|
|
Protrusive interference
|
Premature contact between the mesial aspects of mandibular posterior teeth and the distal aspects of maxillary posterior teeth. – Protrusive Contact |
