Exam 1 Flashcards
What are the criteria for optimum functional occlusion?
- Temporal Bone
- Mandible
- Condyles - in their fossae
- Muscles / Ligaments
- Dentition (secondary to role of muscles)
What two bones is the mandibular or glenoid fossa comprised of?
- Temporal
- Mandible
With the articular disc in between
What is the articular eminence a part of and what are the two sections of it?
Temporal bone:
- Posterior Slope
- Inferior Border
What will guide all mandibular movement?
The angle of the articular eminence (steepness or flatness)
What does the synovial cavities provide?
- Joint Lubrication
- Boundary Lubrication from motion
- What limits excessive protrusive movement of the mandible?
- What plays a roleof limiting protrusive movement and lateral mandibular movement of either the right or left side?
- Stylomandibular Ligament
- Sphenomandibular Ligament
What is the position of the Temporomandibular Ligament designed to do?
Limit the pure hinge axis rotational movement of the mandible
The full length of the temporomandibular ligament occurs at no more than ________ of opening, as measured between the ________ of the maxillary and mandibular incisors. –> Which is classifiesd as _________, then commences?
- 15-20 mm
- Incisal Edges
- Translation
Give the characteristics of the Temporomandibular or Articular Disc. (7 things)
- Fibrous connective tissue
- In between mandible and temporal bone
- Somewhat pliable in texture
- Bi-concave shape
- Collateral ligaments attach it to the condyle in a medial and lateral position
- No innvervation
- No vascularization
What are some characteristics of the muscles of mastication?
- Produces smooth movement
- Limited movement by ligamentous structures
- Bone structures are starting, driven by muscles
- Occlusal interferences or premature occlusal contact MAY lead to spasms
- Opening, closing and lateral movements are most notable types of movement (not protrusion)
- 4 main muscles of mastication
- Muscles are the main driver of the craniomandibular apparatus
- Normal function vs parafunctional
What are the Normal vs Parafunctional actions of the Temporalis?
Normal:
- Elevate the mandible
- Retract or retrude the mandible (helps seat condyles)
- Positions mandible to obtain centric relation
Parafunctional:
- Clenching
- Not normally invovled in lateral movements
What are the normal vs parafunctional actions of the Medial Pterygoid?
Normal:
- Elevate the mandible
- Aids in protrusive movement
- Produces mediotrusive movement (PRIMARY muscle to do so)
Parafunctional:
- Minor player in clenching
What are the normal vs parafunctional actions of the Lateral Pterygoid - Inferior Head?
Normal:
- Active during opening movement
- Primary muscle of mastication for protrusive movement
- Primary muscle of mastication for lateral movement
Parafunctional
- Most frequent muscle to exhibit a spasm - from occlusal dysfunction
- Deep in placement - not easily palpated
Describe the actions of BOTH heads of the Lateral Pterygoid muscles.
- Equally significant roles, but different roles in mandibular movement
- When one is active, the other is minimally contracting
- The coordination of normal activity of both heads is very critical - lack of coordination causes breakdown of normal functioning of the craniomandibular apparatus
What are the actions or functions of the Suprahyoid Accessory Muscles?
- Elevate hyoid bone
- Elevate base of tongue
- Depress mandible (when hyoid fixed)
- Assist in stabilizing the cranium and mandbile during normal movements
- Important for control over the pharynx and esophagus during swallowing and speaking
What muscles display the most problems as a result of occlusal or temporomandibular dysfunction?
- Sternocleidomastoid
- Trapezius
Which teeth only have ONE antagonist in the opposing arch?
- Mandibular central incisors
- Maxillary 3rd molars
Regarding the angulation of the Mandibular Teeth, how do the Anteriors, Premolars and Molars line up?
- Anterior teeth & Molars - incline toward the mesial or anterior region
- Premolars - almost lined up with vertical axis
- Compensating occlusal surface = ?
- The ideal plane is not ______?
- A flat plane allows for what?
- The proper plane of occlusion will permit?
- A curved plane permits?
- How are the teeth positioned?
- Curve of Wilson + Curve of Spee
- Flat
- Too many contacts on most posterior teeth
- Simultaneous functional contacts to occur in controlled areas of the dental arch
- Maximum use of tooth contacts during function
- Strategically in arches at varied and coordinated degrees of inclination
Describe Class 1, Class 2 and Class 3 Lever Designs, and which one do humans have?
- Class 1 - Fulcrum (condyles) in the middle with Load (teeth) and Effort (muscles) on opposite sides = minimal forces, little work, long duration of dentition
- Class 2 - Effort on opposite end of fulcrum, a lot of work can be done on the load, = shorter dention time
- Class 3 - (humans have this) Effort is located in between the load and fulcrum, optimized for 80 years
What does the distal cusp of the mandibular first molar come in contact with (static occlusion) on the maxillary arch?
Distal fossa of the maxillary first molar
What does the mesiolingual cusp of the maxillary second molar line up with (static occlusion) on the mandibular arch?
Central fossa of the mandibular second molar
For the pathways of the Maxillary cusps positioned over the mandibular teeth, define:
Protrusion, Working, Non-Working and Lateral Protrusive
- Protrusion: parallel to the central groove and travels posteriorly
- Working: parallel to the lingual groove and travels toward the tongue
- Non-Working: Parallel to the distofacial groove on the first molar and travels diagonally toward the condyle
- Lateral Protrusive: Located at a 45˚ angle between protrusion and working movements
What is a good, or the only example of translation in the craniomandibular apparatus?
Protrusion of the Mandible
- What is the terminal hinge?
- What are the condyles doing during terminal hinge?
- Is ternimal hinge a reproducible and consistent?
- The rotational movement that occurs from centric relation to the terminal hinge axis position
- Rotating completely within the glenoid fossa
- Yes
In the Sagittal plane, regarding Border Movements:
- What is the most Superior?
- What is the most Anterior?
- What is the most Inferior?
- Which borders invovle tooth contact?
- Maximum Intercuspation
- Maximum Protrusion Point
- Maximum Opening Point
- Centric Relation, Maxiumum Intercuspation, Edge to Edge Incisal, Maximum Protrusion Point
As the mandbile opens, the size of the horizontal plane border ___________ until it reaches a “point” at the ________________?
- Decreases
- Maximum Opening Position
Regarding the Border Movements in the Frontal Plane, Which ones are involved with Tooth contact, and which ones aren’t?
Tooth Contact:
- MI - Maximum Intercuspation
- ELL - Extreme Left Lateral
- ERL - Extreme Right Lateral
No Tooth Contact:
- MO - Max Opening
- CL - Chewing Loop
- RP - Rest Position
What can be seen on the mandibular movement traced at the mandibular incisor level - horizontal plane?
- MP - Max Protrusion
- LL - Left Lateral
- RL - Right Lateral
- CR - Centric Relation
Cant see:
- Maximum Opening
- Rest Position
- Chewing Loop
- Terminal Hinge
How is Mandibular Lateral Translation (Bennet Movement, Immediate Sideshift) of the mandible measured?
The distance between the medial pole of the non-working condyle and the medial wall of the glenoid fossa.
As the condyle moves out of centric relation and descend along the articular eminence, the rate at which it moves inferiorly depends on what?
The steepness or flatness of the eminence
What is the Condylar Guidance Angle?
The angle between the condylar pathway and the horizontal plane
- What are the controlling factors of mandibular movement?
- How does the Medial Wall of the mandibular fossa relate to the articular eminence?
- Are condyles fixed or movable?
- Temporomandibular Joints
- It is generally steeper - contributing to controlling factor for the “non-working condyle”
- Fixed
As Horizontal Overlap increases the anterior guidance angle _________?
An increase in Horizontal Overlap results in less vertical displacement of the mandible and ________________ cusps?
- Decreases
- Flatter posterior
If the movement of the mandible at 4 units horizontally and vertically, what will happen?
It will be ideal because they’re moving at the same rate, moving away from the horizontal plane
The greater the distance of the tooth from the axis or rotation (working condyle) the _________ the angle formed by the laterotrusive and mediotrusive pathways.
Wider
The greater the intercondylar distances, the ___________ the angle formed by the laterotrusive and mediotrusive pathways.
Smaller
(BIG head = smaller angle, SMALL head = bigger angle)
