Flashcards in Midterm Questions from Drive Deck (53)
what is "mesial step"?
the permanent MD first molar is mesial to the permanent MX first molar
curve of spee
anterior-posterior 'curve' along the buccal cusp tips of the permanent MD posterior teeth
condylar path is determined by what skeletal component of mastication system?
articular eminence of the temporal bone
Class 3 dental occlusion?
MB cusp of the permanent MX first molar is DISTAL to the MB cusp of the permanent MD first molar
spaces MESIAL to the developing permanent first molars
spaces mesial to the primary MX canine and DISTAL to the primary MD canine
is a skeletal position and does not refer to a tooth contact position
*most upward, unrestrained position of mandible in glenoid fossa
What makes up the stationary component of the mastication system?
boundary lubrication refers to?
the movement of synovial fluid from one capsular area in the TMJ apparatus to another during joint movement
What muscle along with the masseter muscle forms a 'sling' at the MD angle?
medial pterygoid muscle
curve of wilson
transverse occlusal 'curve' in a buccal-lingual direction of the permanent posterior cusp tips is termed
as articular pressure increases the condyles seats on the?
thin, intermediate zone of the disc
which statement is true concerning the relationship of muscles and the articular surface of the glenoid fossa?
as articular pressure increases the condyles seats on the thin, intermediate zone of the disc
when the mandible and condyle/disc assembly are in a rest position, the condyle and disc are positioned?
when the mandible and condyle/disc assembly are in a rest position, the condyle and disc are positioned anteriorly what best describes the forces exerted by the superior lateral pterygoid muscle and posterior retrodiscal lamina?
the anterior and medial force exerted by the superior lateral pterygoid muscle exceeds the posterior elastic retrodiscal lamina force
motor unit consists of
one motor neuron and a varying number of muscle fibers
describe the motor unit in the lateral pterygoid muscle
lateral pterygoid muscle has a few muscle fibers per motor neuron and controls PROTRUSIVE change in mendibular position
*this reflex causes muscle contraction when a sudden force stretches the muscle
What is responsible for rotational movement in the TMJ?
inferior condyle/disc complex
T/F... ligaments of the TMJ stretch and produce functional movement
false (they do no stretch)
T/F... the articular disc is made of fibrocartilaginous tissue and functions as a true articular surface
what is responsible for the translational movement of TMJ?
superior condyle/disc complex
What type of sensory receptors convey afferent neuron information related to pain and discomfort
example of heterotropic pain? definition?
**where the SITE and SOURCE of the pain are different
major function of the masticatory system include?
mastication of speech
what two phases is the the "chewing stroke" in humans?
1) opening phase
2) closing phase
describe the chewing stroke assuming an Angle's Class 1 occlusion
the mandible drops downward and laterally in the opening phase and the closing phase involves crushing and grinding movements
range of force of mastication?
35-65kg in humans
where is the greatest chewing force in dentition?
1M and 2PM
what happens to occlusion if contact between teeth is lost?
opposing teeth tend to supererupt causing proximal drifting adjacent teeth
posterior teeth have inner and outer aspects of the total buccolingual width. describe the outer aspect?
the outer aspect is the area between the cusp tip and the external height of contour
what % of patients have a preferred chewing side?
T/F... incisal edges of the incisor teeth closely approximate when "S" sounds are made?
T/F... proximal forces on teeth can cause 'mesial drifting' over time?
T/F... the occlusal table is approximately 50% of the total buccolingual width of a posterior tooth?
T/F... in posterior cross-bite situation, the maxillary lingual cusps contact in the central fossa area of the mandibular teeth
T/F... centric cusps or supporting cusps are the mandibular buccal cusps and the maxillary lingual cusps
where does the ML cusp of th MX 1M occlude in class 1 occlusal relationship?
CF of MD 1M
where does the MB cusp of the MX 1M occlude in class 3?
embrasure space between the MD 1M and 2M
which acronym applies to posterior tooth contacts in protrusive MD movement?
describe a tooth contact in a left working side laterotrusice MD movement?
the inner inclines of the MX BCs oppose the outer inclines on the MD BCs
what occurs when the mandible has opened a distance of 20-25mm during a posterior border movement?
a translational opening continues to a distance of 40-60mm
T/F... MD anterior teeth usually contact the MX anterior teeth on the lingual surface 4mm gingival to the incisal edge?
MD tooth BCs may move ___mm _____ in a retrusive mandibular movement?
rotetional MD movement refers to?
translational movement of an object in the same direction
what is the most superior position of the MD condyles from which hinge axis movement can occur is called?
centric relation position
the absence of a slide from CR to the MI position occurs in only ___% of the pospulation
T/F... sagittal plane border movements of the mandible are defined by a "shield-shaped" pattern?
*vertical border movement
is a skeletal position which involves a tooth contact position
*HOW teeth come together in full occlusion
what is the movable component of the masticatory system? stationary?
**(maxillary make up stationary)
T/F... as articular pressure increases the condyles seats on the thin, intermediate zone of the disc
synovial fluid in one tissue goes into another