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In the Sagittal view, the anterior mandibular teeth are inclined labially (mesially).
Curve of ……. is the curve of the occlusal plane when viewed from the sagittal view.
Which of the following is a supporting cusp?
- Select one or more:
- Maxillary Lingual
What percentage does the occlusal table of a posterior tooth make of the total buccolingual dimension of the tooth?
In the incisal guidance variations,The incisal guidance in class III patients is almost 0.
The TMJ has the capability of rotating on a hinge and translating.
Which of the following muscles of mastication inserts into the lateral surface of the mandibular angle?
Identify the part of the articulator labeled #7
Which of the following muscles of mastication move the mandible from side to side?
Which one of the following is an accessory ligament?
The space between maxillary and mandibular teeth when the mandible is at the physiologic rest position is:
The diagram shows the path of the mesio-buccal cusp of mandibular right molar on the right maxillary molar in …………….
The centric relation position of the mandible:
- occurs when the condyles are in the upper most anterior most position in the gleoid fossa
- might not be coincide with the MIP of the mandible
- is a repeatable position of the mandible at various degree of jaw separation
- is bone to bone relationship not tooth to tooth relationship
In left latero-trusion, the outer inclines of the buccal cusps of tooth # 19 may contact the inner inclines of the buccal cusps of tooth # 14
The border movement can not be reproducible because it is limited by ligaments. The only movement that can be reproducible is the functional intra border movement.
both statements are false
The rotation around the terminal hinge axis (Hinge Movement) takes place only in the inferior cavity of the TMJ.
Rotation around the sagittal axis it will give the movement in the ……….
In the right mandibular movement:
the right condyle is the rotating condyle and the left condyle is the orbiting condyle
Pure rotation of the mandible occurs when:
the mandible opens and closes in CR position
The diagram shows the movement of the mandible in the frontal plane, the shape of the upper border is dictated by the teeth and TMJ morphology.
left mandibular movement due to contraction of the right lateral Pterygoid muscle
What does the movement of # 10 represent?
- functional movement
- intraborder movement
- tear drop movement Incorrect
- opening in posterior direction and closing in anterior direction
when the incisal edges of the mandibular incisors move along the path of #5 to the maximum opening #4
- they are in the border movement
- they are translating and rotating
What position does #11 in the image represents?
Edge to edge
The following is true about axial loading
- cusp to fossa occlusion
- tripodization occlusion
- it is about the direction of the forces not the intensity of the force
What term is defined by "bilateral simultaneous stable anterior and posterior occlusal contact in centric and eccentric positions"
The MS position of the joints can be maintained only when it is in harmony with a stable occlusal condition ICP.
In the canine guidance occlusion
- the canine is used because it has long root with more propioception fibers
- the canines are far away from the fulcrum
- it is a mutually protected occlusion
The optimal Stable TMJs position
- when the condyles are in the most superior-anterior position in the articular fossa
- when the condyles are in CR position
- when the muscular position is in optimal position
Edward Angle in 1899 was Orthodontist and the first to describe the occlusal relationships of the teeth.
- bilateral and balancing tooth contacts during all lateral and protrusive movements.
- primarily for stabilizing complete dentures
- later carried over into the field of fixed prosthodontics
unilateral eccentric contact
- developed for natural dentition
- laterotrusive contacts (working contacts) and protrusive contacts should occur only on the anterior teeth.
- during this time gnathology was first used
- considered the ideal occlusal scheme by Gnatholgists
- the science of mandibular movement and resultant occlusal contacts.
- consider unilateral eccentric contact the ideal, any other occlusal scheme malocclusion and to be corrected.
dynamic individual occlusion
focus around the health and function of the masticatory system, not any specific occlusal configuration.
CRITERIA FOR THE OPTIMUM FUNCTIONAL OCCLUSION
TMJs and teeth achieve the stable orthopedic position which will prevent, minimize, or eliminate any breakdown or trauma.
When the elevator muscles function, the mandible is raised and force is applied to ____________.
the two temporomandibular joints (TMJs) and the teeth
centric relation (CR)
- generally considered to designate the position of the mandible when the condyles are in an orthopedically stable position
- Because this position is determined mainly by the ligaments of the TMJ, it has been called a ligamentous position.
- Positional stability of the TMJ is determined by the muscles; musculoskeletally stable (MS) position
- reproducible and reliable mandibular position for complete dentures and fixed prosthodontics.
Optimal orthopedically stable joint position
the condyles are at the most superior and anterior position resting on the discs against the posterior slopes of the articular eminences. also the optimal MS position of the condyles.
Optimum Functional Tooth Contact
- occlusal contact pattern can modify muscular control of mandibular position.
- during unstable occlusal condition, neuromuscular system quickly feeds back appropriate muscle action to change the mandibular position to a more stable occlusal condition. For Example When CR ≠ ICP
- MS position can be maintained only when in harmony with a stable occlusal condition. MS=ICP
- Stable occlusal condition allows for effective functioning while minimizing damage to any components of the masticatory system.
- If CR ≠ ICP, the optimum functional occlusion can be related to the modified stable MS position of the condyles
PDL is composed of _________ that suspend the tooth in the bony socket. Most fibers run _______ from the ________, extending _______ to attach in the ______.
- collagenous connective tissue fibers
PDL is capable of converting a ________ into _________ as a shock absorber controlling the occlusal forces on the bone.
- destructive force (pressure)
- an acceptable force (tension)
PDL are aligned to withstand forces directed ________. When a tooth is contacted on a cusp tip or a relatively flat surface such as the bottom of a fossa, the resultant force is directed _______. When a tooth is contacted on an incline, however, _________ and tends to cause __________.
- vertically through the tooth long axis
- vertically through its long axis
- a horizontal component is incorporated
- tipping, i.e. compression of certain areas of PDL and elongation of other areas with pathologic effect
The process of directing occlusal forces through the long axis of the tooth is known as ______.
Two methods of Axial Loading:
- Cusp to fossa/marginal ridge
- Tripodization - The cusp contacting an opposing fossa such that it produces three contacts surrounding the actual cusp tip.
eccentric movements such as lateral and protrusive excursions produce _______.
lateral horizontal forces
the most desirable position for generating high occlusal forces is between the _____ teeth, because it is ____ to the fulcrum (the TMJ) of the lever system of the mandible.
The damaging horizontal forces of eccentric movement must be directed to the ______ teeth, which are positioned _______ from the fulcrum.
The _______ are best suited to accept the horizontal forces with posterior teeth disclusion (_______ Guidance) because: the longest and largest roots hence the best _______; surrounded by ____; have ________ and the resultant effect of immediate shutdown of most of the elevators muscles which minimize the lateral destructive forces on the anterior teeth.
- crown/root ratio
- dense compact bone
- sensory input
The most favorable alternative to canine guidance occlusion is _______, in which several teeth on the working side _________ contact during the laterotrusive movement.
- Group Function occlusion
- (canines, premolars, MBC of first molar)
The laterotrusive contacts need to provide adequate guidance to _______.
disocclude the teeth on the opposite side of the arch (mediotrusive or nonworking side)
During protrusion __________ should be in contact, since _____.
- the anterior and not the posterior teeth
- the anterior teeth can best receive and dissipate these forces
Mutually Protected Occlusion
- Posterior teeth function most effectively in stopping the mandible during closure
- Anterior teeth function most effectively in guiding the mandible during eccentric movements.
- Posterior teeth should contact slightly more heavily than anterior teeth when the teeth are occluded in the ICP
- This condition is described as Mutually Protected Occlusion
Temporomandibular joints (TMJs) and anterior teeth determine the movement patterns of mandible, dictating precise and repeatable pathways.
To maintain harmony of the occlusal condition, the posterior teeth must ___________ their opposing teeth during mandibular movement.
pass close to but must not contact
The structures that control mandibular movement are divided into two types:
- those that influence posterior mandible movement
- those that influence anterior mandible movement
The _____ are considered the Posterior Controlling Factors (PCFs), and the _______ are considered the Anterior Controlling Factors (ACFs). The _________ are positioned between these two controlling factors and thus can be affected by both to varying degrees.
- anterior teeth
- posterior teeth
Condylar Guidance Angle
The angle at which the condyle moves away from a horizontal reference plane
The condylar guidance angle generated by the orbiting condyle when the mandible moves laterally is _________ than when the mandible protrudes straightforward. This is because _____________.
- larger (steeper)
- the medial wall of the mandibular fossa is generally steeper than the articular eminence of the fossa
The condylar guidance is considered to be a ___ factor.
Anterior (Incisal) Guidance
- = Vertical overlap + Horizontal overlap
- considered as a variable factor
Factors that influence the heights of cusps and the depths of fossae are the vertical determinants of occlusal morphology:
- The PCF of mandibular movement, condylar guidance
- The ACF of mandibular movement, anterior guidance
- The nearness of the cusp to these controlling factors
EFFECT OF CONDYLAR GUIDANCE (ANGLE OF THE EMINENCE) ON CUSP HEIGHT
The steeper the eminence, the steeper the posterior cusps.
EFFECT OF ANTERIOR GUIDANCE ON CUSP HEIGHT
The steeper the incisal giudace, the steeper the posterior cusps.
EFFECT OF THE CURVE OF SPEE ON CUSP HEIGHT
The flatter the plane of occlusion, the taller the cusp. The more acute the plane of occlusion, the flatter the teeth.
EFFECT OF MANDIBULAR LATERAL TRANSLATION MOVEMENT ON CUSP HEIGHT (Amount)
- The degree of this movement is determined by morphology of the medial wall of the mandibular fossa of the orbiting condyle & the tightness of temporomandibular (TM) ligament of the rotating condyle
- The more the lateral translation movement, the shorter the posterior cusps.
EFFECT OF MANDIBULAR LATERAL TRANSLATION MOVEMENT ON CUSP HEIGHT (Direction)
The more superior the lateral translation movement of the rotating condyle, the shorter the posterior cusp.
EFFECT OF MANDIBULAR LATERAL TRANSLATION MOVEMENT ON CUSP HEIGHT (Timing)
The more immediate the lateral translation, the shorter the posterior cusp.
The wider the angle between the laterotrusive & mediotrusive patways, the ________ is the groove on the maxillary tooth and ________ is the groove on the mandibular tooth.
EFFECT OF DISTANCE FROM THE ROTATING CONDYLE ON RIDGE AND GROOVE DIRECTION
The greater the distance of the tooth from the rotating condyle, the wider the angle formed by the laterotrusive and mediotrusive pathways, the more mesial are the ridges & grooves in mandibular teeth
EFFECT OF amount of LATERAL TRANSLATION MOVEMENT ON RIDGE AND GROOVE DIRECTION
the more the amount of lateral translation movement, the wider the angle between mediotrusive and laterotrusive pathways.
EFFECT OF INTER CONDYLER DISTANCE ON RIDGE AND GROOVE DIRECTION
The greater the intercondylar distances, the smaller the angle formed by the laterotrusive and mediotrusive cusp pathways, the more distal are the ridges & grooves in mandibular teeth