Components of masticatory function. (3)
- mastacatory system
Components the of masticatory system. (3)
- temporomandibular joint
The static relationship between the incising or masticating surfaces of the maxillary or mandibular teeth or tooth analogues.
Types of occlusion. (2)
- static occlusion
- dynamic occlusion
Aspects of static occlusion. (3)
- maximum intercuspation
- centric relation
- centric occlusion
The complete intercuspation of the opposing teeth independent of condylar position, sometimes referred to as the best fit of the teeth regardless of the condylar position.
maximum intercuspal position (MICP)
The occlusion of opposing teeth when the mandible is in centric relation; this may or may not coincide with the maximal intercuspal position.
centric occlusion (CO)
A maxillomandibular relationship, independent of tooth contact, in which the condyles articulate in the anterior-superior position against the posterior slopes of the articular eminences.
centric relation (CR)
Three ways to define centric relation.
Anatomical definition of CR.
The position of the mandible in relation to the maxilla with intra-articular disc in place, in which the head of the condyle is against the most superior part of the distal facing incline of the glenoid fossa.
Conceptual definition of CR.
The position of the mandible in relation to the maxilla with intra-articular disc in place, in which the muscles that support the mandible are at their most relaxed and less strained position.
Geometric definition of CR.
The position of the mandible in relation to the maxilla with intra-articular disc in place, in which the head of the condyle is in terminal hinge axis.
Two types of movement occur in the TMJ.
The axis about which movement occurs when the condyles are in their most superior position in the articular fossae and the mouth is purely rotated open.
terminal hinge axis
Clinical significance of CR.
It is a reproducible position of the mandible relative to the maxilla, independent of tooth surfaces or occlusion; even completely edentulous patients still have a centric relation.
Aspects of dynamic occlusion. (3)
- posterior controlling factors (condylar guidance)
- anterior controlling factors (anterior guidance)
- ideal occlusion
Provides posterior guidance of the mandible.
temporomandibular joints (TMJs)
Determine the pathway of mandibular movement. (3)
- intra-articular disc
- articular surfaces of the glenoid fossa
- articular eminence
The angle at which the condyle moves away from a horizontal reference plane.
condylar guidance angle
Condylar guidance is naturally a (...) factor.
Provides anterior guidance of the mandible.
In eccentric movements, the mandibular (...) occlude with the (...) of the maxillary anterior teeth.
incisal edges; lingual surfaces
Anterior guidance is naturally a (...) factor.
Dynamic occlusion that occurs on the canines during a lateral excursion of the mandible.
When canine guidance is the only dynamic occlusal contact during excursive movement.
canine protected occlusion
When contacts are shared between several teeth on the working side during a lateral excursion.
Any tooth contact that inhibits the remaining occluding surfaces from achieving stable and harmonious contacts.
Occlusal interference is always problematic. True or false?
False; it may be considered as potentially damaging in some subjects, but others may adapt to it.
The side of mandible towards which the mandible is moving during a lateral excursion.
The side of mandible away from which the mandible is moving during a lateral excursion.
Any heavy or early occlusal contact of the teeth on the same side side as the direction of laterotrusion of the mandible.
working side interference
Any heavy or early occlusal contact of the teeth on the opposite side as the direction of laterotrusion of the mandible.
non-working side interference
When are non-working side contacts are desirable?
With removable complete dentures when establishing bilateral balanced articulation.
How does the position of a tooth in the mouth affect its likelihood of causing occlusal interference?
Since posterior teeth are closer to the TMJ, they are more likely to cause interference; anterior teeth are further from the TMJ, and are less likely to cause interference.
Anterior controlling factors on back teeth, while still providing anterior guidance, is described as a (...) because it may interfere with the posterior guidance system of the mandible.
Components of ideal occlusion. (3)
- anterior guidance of the mandible is solely the dynamic occlusal contacts between anterior teeth (joint)
- teeth fit together in a position where the muscles are at their most relaxed and less strained (muscles)
- anterior guidance is provided by incisal guidance in protrusion and canine guidance in lateral excursion (teeth)
Two joint systems of the TMJ.
- superior joint system
- inferior joint system
The superior joint system of the TMJ is responsible for (...) movement of the mandible.
The inferior joint system of the TMJ is responsible for (...) movement of the mandible.
In normal functional movement of the condyle and disc during the full range of opening and closing, the disc is rotated (...) on the condyle as the condyle is translated out of the fossa.
Three major skeletal components of the masticatory system.
- temporal bone
The maxilla is develops as two bones fused at the (...).
Superiorly, the maxilla forms the (...).
floor of the nasal cavity and orbits
Inferiorly, the maxilla forms the (...).
palate and alveolar ridges
The ascending ramus of the mandible extends upward to form the (...) and the (...).
coronoid proccess; condyle
In an anterior view of the condyle, the (...) pole is more prominent than the (...) pole.
In an inferior view of the mandible, the condyle seem to be slightly rotated so that if an imaginary line were drawn through the lateral and medial poles it would extend (...) toward the anterior border of the (...).
medially and posteriorly; foramen magnum
The articular surface on the (...) aspect of the condyle is greater than on the (...) aspect.
The articulating surface of the condyle is quite convex (...) and only slightly convex (...).
The posterior roof of the (...) is quite thin, indicating that this area of the temporal bone is not designed to sustain heavy forces.
Posterior to the mandibular fossa is the (...), which extends mediolaterally.
Immediately anterior to the mandibular fossa is a convex bony prominence called the (...), which consists of thick dense bone and is more likely to tolerate such forces.
A vital function to ensure ingested food is broken down and prepared for digestion.
Primary muscles of mastication. (4)
- medial pterygoid
- lateral pterygoid
Medial and lateral pterygoids lie in the (...) fossa.
The temporalis muscle is situated in the (...) fossa.
Five movements of the mandible.
- protrusion (forwards)
- retrusion (backwards)
- depression (downwards)
- elevation (upwards)
- rotation (side-to-side)
All muscles of mastication are innervated by motor fibers of the (...), while the main arterial supply is derived from branches of the (...).
mandibular nerve (V3); maxillary artery
A rectangular muscle that originates from the zygomatic arch and extends downward to the lateral aspect of the lower border of the ramus of the mandible.
The masseter is made up of two portions or heads: the superficial portion consists of fibers that run (...); the deep portion consists of fibers that run in a predominantly (...) direction.
downward and backward; vertical
Function of the masseter.
elevation and protrusion of the mandible
Innervation of the masseter.
masseteric branch of the mandibular nerve
Blood supply of the masseter.
The (...) provokes elevation of the mandible in response to a tap on the jaw; a pathological response indicates (...).
masseteric (jaw jerk) reflex; lesion of the trigeminal nerve
Infections and submasseteric abscesses of odontogenic origin are often confused with (...), and may cause (...).
parotid gland infections; trismus
The (...) is a large, fan-shaped muscle that originates from the temporal fossa and the lateral surface of the skull, forming a tendon that inserts on the coronoid process and anterior border of the ascending ramus.
The anterior portion of the temporalis consists of fibers that are directed almost (...).
The middle portion of the temporalis contains fibers that run (...) across the lateral aspect of the skull.
The posterior portion of the temporalis consists of fibers that are aligned almost (...).
Function of the temporalis.
elevation and retrusion of the mandible
Innervation of the temporalis.
deep temporal nerve from the mandibular nerve
Blood supply of the temporalis.
anterior, posterior, and superficial temporal arteries
Pain in the temporalis can be caused by excessive tension (e.g. bruxism, prolonged opening), but it is important to rule out (...).
vasculitides (e.g. giant cell arteritis)
The (...) originates from the pterygoid fossa and extends downward, backward, and outward to insert along the medial surface of the mandibular angle.
The deep head of the medial pterygoid is larger than its superficial head, which are separated by the (...) at their origin.
inferior head of lateral pterygoid muscle
Function of the medial pterygoid.
elevation and protrusion of the mandible
Innervation of the medial pterygoid.
medial pterygoid branches of mandibular nerve
Blood supply of the medial pterygoid.
pterygoid and buccal branches of maxillary artery
The medial pterygoid can be injured during (...), resulting in inability to open the mouth or pain when opening beyond the restriction.
inferior alveolar nerve block
The (...) originates at the outer surface of the lateral pterygoid plate and extends backward, upward, and outward to its insertion primarily on the neck of the condyle.
inferior lateral pterygoid
Function of the inferior lateral pterygoid.
protrusion and lateral movement of the mandible
Innervation of the inferior lateral pterygoid.
pterygoid branch of the trigeminal nerve
Blood supply of the inferior lateral pterygoid.
pterygoid branch of the maxillary artery
The (...) originates at the infratemporal surface of the greater sphenoid wing, extending almost horizontally, backward, and outward to insert on the articular capsule, the disc, and the neck of the condyle.
superior lateral pterygoid
Function of the superior lateral pterygoid.
stabilizes the condyle and disc
Innervation of the superior lateral pterygoid.
pterygoid branch of the trigeminal nerve
Blood supply of the superior lateral pterygoid.
pterygoid branch of the maxillary artery
While the (...) lateral pterygoid is active during opening, the (...) remains inactive, becoming active only in conjunction with the elevator muscles.
Muscles that function in elevation of the mandible.
- medial pterygoid
Muscles that function in protrusion of the mandible.
- medial pterygoid
- inferior lateral pterygoid
Muscles that function in retrusion of the mandible.
Accessory muscles directly associated with mandibular function. (8)
- suprahyoid muscles
- infrahyoid muscles
Accessory muscles indirectly associated with mandibular function. (4)
- scalenus anterior
- scalenus medius
- scalenus posterior
Extrinsic muscles of the tongue.
Intrinsic muscles of the tongue. (4)
- superior longitudinal
- inferior longitudinal
- transverse muscles
- vertical muscles
Six types of synovial joints.
- gliding (arthrodial)
- hinge (ginglymoid)
- pivot (trochoid)
- ball-and-socket (spheroid)
- saddle (modified ellipsoidal)
- condyloid (ellipsoidal)
Example of an arthrodial (gliding) joint.
Example of a ginglymoid (hinge) joint.
Example of a trochoid (pivot) joint
Example of a spheroid (ball-and-socket) joint.
Example of a modified ellipsoidal (saddle) joint.
Example of an ellipsoidal (condyloid) joint.
What type of joint is the TMJ?
The TMJ, made up of only two bones, is classified as a compound joint, which by definition requires the presence of at least three bones; this is because functionally, the (...) serves as a nonossified bone that permits the complex movements of the joint.
The articular disc is composed of (...), for the most part devoid of any blood vessels or nerve fibers; the (...) of the disc, however, is slightly innervated.
dense fibrous connective tissue; extreme periphery
In the sagittal plane, the articular disc can be divided into three regions according to thickness; the (...) is approximately 1 mm, the (...) is approximately 2 mm, and the (...) is approximately 3 mm.
- intermediate zone
- anterior border
- posterior border
From an anterior view, the articular disc is generally thicker (...) than (...), which corresponds to the increased space between the condyle and the articular fossa.
The articular disc is attached posteriorly to a region of loose connective tissue that is highly vascularized and innervated, known as the (...) or posterior attachment.
Superiorly, the retrodiscal tissue is bordered by the (...), which contains (...), and attaches the articular disc posteriorly to the (...).
superior retrodiscal lamina; elastic fibers; tympanic plate
Inferiorly, the retrodiscal tissue is bordered by the (...), which contains (...), and attaches the articular disc posteriorly to the (...).
inferior retrodiscal lamina; collagenous fibers; articular surface of the condyle
The remaining body of the retrodiscal tissue is attached posteriorly to a large (...), which fills with blood as the condyle moves forward.
The superior and inferior attachments of the anterior region of the articular disc are to the (...), which surrounds most of the joint.
The superior anterior attachment of the articular disc is to the anterior margin of the articular surface of the (...).
The inferior anterior attachment of the articular disc is to the anterior margin of the articular surface of the (...).
Anteriorly, between the attachments of the capsular ligament the articular disc is also attached by tendinous fibers to the (...) muscle.
superior lateral pterygoid
Articular disc is attached to the (...) medially and laterally, which divides the joint into two distinct cavities.
The (...) is bordered by the mandibular fossa and the superior surface of the articular disc.
upper or superior cavity
The (...) is bordered by the mandibular condyle and the inferior surface of the articular disc.
lower or inferior cavity
The internal surfaces of the superior and inferior joint cavities are surrounded by specialized (...) cells that form a (...).
endothelial; synovial lining
The synovial lining, along with a specialized (...) located at the anterior border of the retrodiscal tissues, produces (...).
synovial fringe; synovial fluid
A fibrous membrane that surrounds the joint and attaches to the articular eminence, the articular disc, and the neck of the mandibular condyle.
synovial (articular) capsule
A thin membrane of joints comprised of smooth connective tissue and that secretes synovial fluid.
A viscous fluid found in the cavities of synovial joints that reduces friction between the articular cartilage of synovial joints during movement.
A tough, elastic, fibrous connective tissue found covering the surfaces of articulating bones, and in other parts of the body such as the outer ear and larynx.
The synovial capsule is fibrous and continuous with the (...), surrounding the synovial joint and uniting the articulating bones.
periosteum of articulating bones
The synovial capsule consists of an outer (...) that may contain ligaments, and an inner (...) that secretes the synovial fluid.
fibrous membrane; synovial membrane
The synovial membrane lines the inner side of the capsule and articular disc, but not the (...).
The synovial membrane consists of an outer (...), which blends with the fibrous layers of the capsule, and an inner (...), which faces the joint cavity.
vascular subintima; cellular intima
Functions of synovial fluid. (2)
- acts as a medium for providing metabolic requirements to the avascular articular surfaces of the joint
- serves as a lubricant between articular surfaces during function
Type of lubrication that occurs when the joint is moved and the synovial fluid is forced from one area of the cavity into another.
Type of lubrication that occurs when forces drive a small amount of synovial fluid in and out of the articular tissues.
Primary mechanism of synovial fluid joint lubrication.
Primary mechanism of synovial fluid metabolic exchange.
The articular cartilage of the TMJ is set up very differently from typical articular cartilage because the mandible and TMJ form from (...) rather than from (...).
intermembranous ossification; endochondral ossification
Because the mandible and TMJ form from intermembranous ossification, the articular fibrocartilage of the TMJ keeps its (...) buried deep within it, unlike typical articular cartilage.
The four distinct layers or zones of articular cartilage.
- articular zone
- proliferative zone
- fibrocartilaginous zone
- calcified cartilage zone
The zone of articular cartilage found adjacent to the joint cavity, made of dense fibrous connective tissue rather than hyaline cartilage like in other most other synovial joints.
The zone of articular cartilage responsible for the proliferation of articular cartilage in response the functional demands placed on the articular surfaces during loading.
The zone of articular cartilage composed of collagen fibrils arranged in a crossing pattern, providing a three-dimensional network that offers resistance against compressive and lateral forces.
The zone of articular cartilage found deepest from the joint cavity, made up of chondrocytes and chondroblasts distributed throughout the articular cartilage.
calcified cartilage zone
The predominant vessels supplying the TMJ. (3)
- superficial temporal artery (from the posterior)
- middle meningeal artery (from the anterior)
- internal maxillary artery (from the inferior)
Other important arteries supplying the TMJ. (3)
- deep auricular
- anterior tympanic
- ascending pharyngeal arteries
Vascularization to the TMJ is (...) in nature only; within the capsule is supplied through (...).
superficial; synovial fluid
Most innervation of the TMJ.
Provide proprioception from the TMJ. (4)
- masticatory muscles
- skin receptors
- ligament receptors
Do not enter actively into joint function but instead act as passive restraining devices to limit and restrict border movements.
Ligaments are made up of (...) that do not stretch. However, if extensive forces are applied to a ligament, it can become (...).
collagenous connective tissues fibers; elongated
Functional ligaments of the TMJ. (3)
- collateral (discal) ligaments
- capsular ligament
- temporomandibular ligament (TML)
Accessory ligaments of the TMJ. (2)
- sphenomandibular ligament
- stylomandibular ligament
The (...) attach the medial and lateral borders of the articular disc to the poles of the condyle.
collateral (discal) ligaments
The medial discal ligament attaches the medial edge of the disc to the (...).
medial pole of the condyle
The lateral discal ligament attaches the lateral edge of the disc to the (...).
lateral pole of the condyle
The collateral (discal) ligaments are responsible for dividing the joint mediolaterally into the (...).
superior and inferior joint cavities
The discal ligaments have a (...) supply and are (...). Strain on these ligaments produces pain.
The discal ligaments function to restrict (...), which is enables the (...) movement of the TMJ.
movement of the disc away from the condyle; hinging
The entire TMJ is surrounded and encompassed by the (...).
The fibers of the capsular ligament are attached superiorly to the (...) and inferiorly to the (...).
temporal bone; neck of the condyle
The capsular ligament acts to resist any medial, lateral, or inferior forces that tend to (...).
separate or dislocate the articular surfaces
A significant function of the capsular ligament is to encompass the joint, thus retaining the (...).
The capsular ligament is well innervated and provides (...) feedback regarding position and movement of the joint.
The lateral aspect of the capsular ligament is reinforced by strong, tight fibers that make up the (...).
The temporomandibular ligament is composed of two parts, an outer (...) and an inner (...).
oblique portion; horizontal portion
The outer oblique portion of the TML extends from the outer surface of the (...) posteroinferiorly to the outer surface of the (...).
articular tubercle and zygomatic process; condylar neck
The inner horizontal portion of the TML extends from the outer surface of the (...) posteriorly and horizontally to the (...).
articular tubercle and zygomatic process; lateral pole of the condyle and posterior part of the articular disc
The oblique portion of the TM ligament resists excessive (...).
dropping of the condyle
The outer oblique portion of the TM ligament, which limits rotational opening, is unqiue because it is (...).
found only in humans
The inner horizontal portion of the TM ligament limits (...).
posterior movement of the condyle and disc
The inner horizontal portion of the TM ligament also protects the (...) muscle from overlengthening or extension.
The effectiveness of the inner horizontal portion of the TM ligament is demonstrated during cases of extreme trauma to the mandible, in which the (...) will be seen to fracture before the (...) are severed or the condyle enters the (...).
neck of the condyle; retrodiscal tissues; middle cranial fossa
Arises from the spine of the sphenoid bone and extends downward to lingula on the medial surface of the ramus of the mandible.
Arises from the styloid process and extends downward and forward to the angle and posterior border of the ramus of the mandible.
The stylomandibular ligament becomes taut when the mandible is (...), but is most relaxed when the mandible is (...).
The major opposing forces that influence tooth position originate from the (...).
Labial to the teeth are the lips and cheeks, which provide relatively light but constant (...) directed forces.
On the opposite side of the dental arches is the tongue, which provides (...) directed forces to the lingual surface of the teeth.
labially and buccally
The tooth position in the oral cavity where the labiolingual and buccolingual forces are equal.
neutral position or space
Occurs when there is inadequate space for the tooth within the dental arch and the tooth remains outside the normal arch form.
tooth size-arch length discrepancy (TSALD)
Formula for space analysis.
TSALD = Space Available (SA) –Space Required (SR)
Occurs when the tongue is unusually active or large, resulting in greater forces applied lingually than labially to the teeth.
In the case of anterior open bite, the neutral space is not lost but is merely (...).
displaced to the labial
The forces applied by the tongue when this patient swallows are responsible for the labial displacement or flaring of the anterior teeth. True or false?
Recent evidence does not substantiate this concept; it is more likely that the anterior teeth are displaced labially by the constant resting position of the tongue, and the tongue is thrust forward during swallowing in an attempt to seal the mouth.
Forces not directly derived from the oral musculature but associated with (...) can also influence tooth position.
oral habits (e.g. musical instruments)
(...) between adjacent teeth helps maintain the teeth in normal alignment.
A functional response of the alveolar bone and the gingival fibers surrounding the teeth appears to result in a (...) drifting of the teeth.
Mesial drifting of teeth helps maintain (...) between adjacent teeth and thus stabilizes the arch.
(...) prevents the extrusion or supereruption of teeth, maintaining arch stability.
Roth's (1979) five fundamental aspects of functional occlusion for completion of orthodontic treatment.
- teeth must present MIP with jaw in CR
- in CR, all posterior teeth must present axial occlusal contacts and anterior teeth must maintain an overbite and overlap
- presence of canine guidance
- presence of anterior guidance
- no occlusal interference on the balancing side
When the occlusal surface of a tooth is lost or altered, periodontal supportive structures will allow (...).
shifting of the tooth
Unopposed teeth are likely to (...) until occlusal contact is established.
With loss of the mandibular first molar, the mandibular second and third molars tip (...), the mandibular second premolar moves (...), and the opposing maxillary first molar is (...).
mesially; distally; supererupted
Refers to the relationship of the teeth to each other within the dental arch.
intraarch tooth alignment
The plane that would be established if a line were drawn through all the buccal cusp tips and incisal edges of the mandibular teeth, then broadened to include the lingual cusp tips and continuing across the arch to include the opposite side buccal and lingual cups tips.
plane of occlusion
The occlusal planes of the dental arches are (...) in a manner that permits maximum utilization of tooth contacts during function.
When examining the arches from the lateral view, the (...) axial relationship can be seen.
In a lateral view of the mandibular arch, both the anterior and the posterior teeth are (...) inclined.
In a lateral view of the maxillary arch, the anterior teeth are generally (...) inclined, with the most posterior molars being (...) inclined.
If an imaginary line is drawn through the buccal cusp tips of the posterior teeth, a curved line following the plane of occlusion will be established that is convex for the maxillary arch and concave for the mandibular arch, called the (...).
curve of Spee
When observing the dental arches from the frontal view, the (...) axial relationship can be seen.
In a frontal view of the maxillary arch, the posterior teeth generally have a slightly (...) inclination.
In a frontal view of the mandibular arch, the posterior teeth generally have a slightly (...) inclination.
If an imaginary line is drawn through the buccal and lingual cusp tips of both the right and the left posterior teeth, a curved plane of occlusion will be observed that is convex in the maxillary arch and concave in the mandibular arch, called the (...).
curve of Wilson
The area of the tooth between the buccal and lingual cusp tips of the posterior teeth.
The occlusal table represents approximately (...)% of the total buccolingual dimension of the posterior tooth and is positioned over the long axis of the root structure.
50% to 60%
The occlusal table is considered the (...) of the tooth, since it falls between the cusp tips, while the the occlusal area outside the cusp tips is called the (...).
inner aspect; outer aspects
The surfaces of the inner aspects that extend from the cusp tips to the central fossa areas.
The surfaces of the outer aspects that extend from the cusp tips to the height of the contour.
The surfaces of the cusp that face the mesial portion of the tooth.
The surfaces of the cusp that face the distal portion of the tooth.
Refers to the relationship of the teeth in one arch to those in the other.
interarch tooth alignment
When the two arches come into contact, as in mandibular closure, the (...) of the teeth is established.
The distance of a line that begins at the distal surface of the third molar extends mesially through all of the proximal contact areas around the entire arch, and ends at the distal surface of the opposite third molar.
Both arches have approximately the same length, with maxillary arch being (...) mm and mandibular arch (...) mm.
128 mm; 126 mm
This slight difference between the maxillary and mandibular arch lengths is a result of the (...).
narrower mesiodistal distance of the mandibular incisors compared to the maxillary incisors
The distance across the arch.
The width of the mandibular arch is slightly (...) than that of the maxillary arch; thus when the arches occlude, each maxillary tooth is more (...) positioned than the occluding mandibular tooth.
The (...) cusps of the mandibular posterior teeth and the (...) cusps of the maxillary posterior teeth occlude with the opposing central fossa areas.
The buccal cusps of the mandibular posterior teeth and the lingual cusps of the maxillary posterior teeth are called the (...).
supporting cusps or centric cusps
The centric cusps are primarily responsible for maintaining the distance between the maxilla and mandible, called the (...).
vertical dimension of occlusion
Centric cusps also play a major role in (...) since contact occurs on both the inner and the outer aspect of the cusps.
The centric cusps are broad and rounded, and when viewed from the occlusal, their tips are located approximately (...) the distance into the total buccolingual width of the tooth.
The buccal cusps of the maxillary posterior teeth and the lingual cusps of the mandibular posterior teeth are called the (...).
guiding or noncentric cusps
The major role of the noncentric cusps is to minimize (...), and to maintain the (...) for mastication.
tissue impingement; bolus of food on the occlusal table
The noncentric cusps are relatively sharp, with definite tips that are located approximately (...) the distance into the total buccolingual width of the tooth.
The small (about 1 mm) area located on the inner incline of the noncentric cusps near the central fossa of the tooth that contacts a small portion of the outer aspect of the opposing centric cusp.
functional outer aspect
Since this functional outer aspect assists in the shearing of food during mastication, the noncentric cusps have also been called (...).
If the mandible moves laterally from the intercuspal position, the noncentric contact will contact and guide it, therefore the noncentric cusps are also appropriately referred to as (...).
In a normal buccolingual arch relationship, the mandibular (...) cusps occlude in the central fossae of the maxillary teeth and the maxillary (...) cusps occlude in the central fossae of the mandibular teeth.
In posterior cross-bite, the mandibular (...) cusps occlude in the central fossae of the maxillary teeth and the maxillary (...) cusps occlude in the central fossae of the mandibular teeth.
An imaginary line extending through the buccal cusp tips of the mandibular posterior teeth.
buccoocclusal (B-O) line
An imaginary line extending through the lingual cusps of the maxillary posterior teeth.
linguo-occlusal (L-O) line
An imaginary line extending through the central developmental grooves of the maxillary and mandibular posterior teeth.
central fossa (C-F) line
The (...) line of the mandibular teeth occludes in the (...) line of the maxillary teeth.
buccoocclusal; central fossa
The (...) line of the maxillary teeth occludes in the (...) line of the mandibular teeth.
linguo-occlusal; central fossa
The proximal contact areas between posterior teeth are generally located (...) to the central fossa line.
The buccal location of the proximal contact on posterior teeth allows for a greater (...) embrasure area and a smaller (...) embrasure.
Viewed from the facial, centric cusps typically contact in one of two areas: (1) the (...) areas and (2) the (...) areas.
central fossa; marginal ridge and embrasure
When the normal interarch tooth relationship is viewed from the lateral, it can be seen that each tooth occludes with (...) opposing teeth, except for the (...), which occlude with (...).
two; mandibular central incisors and maxillary third molars; one
Each mandibular posterior tooth is situated slightly (...) to its maxillary counterpart.
lingual and mesial
Any given tooth is found to occlude with its (...) in the opposing arch plus (...).
namesake; an adjacent tooth
Some centric cusps occlude in the embrasures between opposing teeth, causing (...) contacts surrounding the cusp tip.
Some centric cusps occlude in an embrasure area and contact only (...) opposing marginal ridge.
The relationship between the mandibular first molar and maxillary first molar is referred to as its (...).
The (...) molar relationship is the most common found in the natural dentition.
In an Angle Class I molar relationship, the mesiobuccal cusp of the mandibular first molar occludes in the (...).
embrasure between the maxillary second premolar and first molar
In an Angle Class I molar relationship, the mesiobuccal cusp of the maxillary first molar is aligned directly over the (...).
buccal groove of the mandibular first molar
In an Angle Class I molar relationship, the mesiolingual cusp of the maxillary first molar is situated in the (...).
central fossa area of the mandibular first molar
In an Angle Class II molar relationship, the mesiobuccal cusp of the mandibular first molar occludes in the (...).
central fossa area of the maxillary first molar
In an Angle Class II molar relationship, the mesiobuccal cusp of the mandibular first molar is aligned with the (...).
buccal groove of the maxillary first molar
In an Angle Class II molar relationship, the distolingual cusp of the maxillary first molar occludes in the (...).
central fossa area of the mandibular first molar
When compared to the Class I relationship, each occlusal contact pair in Class II is situated to the (...) by approximately the (...).
distal; mesiodistal width of a premolar
In an Angle Class III molar relationship, the distobuccal cusp of the mandibular first molar is situated in the (...).
embrasure between the maxillary second premolar and first molar
In an Angle Class III molar relationship, the mesiobuccal cusp of the maxillary first molar is situated over the (...).
embrasure between the mandibular first and second molar
In an Angle Class III molar relationship, the mesiolingual cusp of the maxillary first molar is situated in the (...).
mesial pit of the mandibular second molar
When compared to the Class I relationship, each occlusal contact pair in Class III is situated to the (...) by approximately the (...).
mesial; mesiodistal width of a premolar
Like the maxillary posterior teeth, the maxillary anterior teeth are normally positioned (...) to the mandibular anterior teeth.
Unlike the posterior teeth, both maxillary and mandibular anteriors are inclined to the (...) by (...)° degrees from a vertical reference line.
labial; 12 to 28°
The normal occlusal relationship will find the (...) of the mandibular incisors contacting the (...) of the maxillary incisors.
incisal edges; lingual surfaces
Incisal contacts commonly occur in the lingual fossae of the maxillary incisors approximately (...) mm gingival to the incisal edges.
When viewed from the labial, (...) mm of the mandibular anterior teeth is hidden by the maxillary anterior teeth.
3 to 5 mm
The distance between the labial incisal edge of the maxillary incisor and the labial surface of the mandibular incisor in the intercuspal position.
horizontal overlap (sometimes called overjet)
The distance between the incisal edges of the opposing anterior teeth.
vertical overlap (sometimes called overbite)
When a person has an underdeveloped mandible, and the mandibular anterior teeth contact at the gingival third of the lingual surfaces of the maxillary teeth.
If the maxillary central and laterals are at a normal labial inclination in an anterior Class II relationship.
class II, division 1
If the maxillary incisors are lingually inclined in an anterior Class II relationship.
class II, division 2
When a person has pronounced mandibular growth, and the mandibular anterior teeth are positioned forward and contact with the incisal edges of the maxillary anterior teeth.
end-to-end (or edge-to-edge)
In anterior tooth relationship in which there is negative vertical overlap with the posterior teeth in maximum intercuspation.
Any movement of the mandible from the intercuspal position that results in tooth contact.
The three basic eccentric movements of the mandible.
A (...) mandibular movement occurs when the mandible moves forward from the intercuspal position.
Any area of a tooth that contacts an opposing tooth during protrusive movement is considered to be a (...).
Anterior protrusive contacts occur between the (...) of the mandibular incisors against the (...) of the maxillary incisors.
incisal and labial edges; lingual fossae and incisal edges
The (...) of the maxillary teeth are the surfaces responsible for the characteristics of anterior guidance.
guiding inclines (GI)
Posterior protrusive contacts can occur between (...) of maxillary teeth and (...) of mandibular teeth.
distal inclines; mesial inclines
During a (...) mandibular movement, the mandibular posterior teeth move across their opposing teeth in different directions.
Any contacts that occur on the left side during left laterotrusive movement are called (...).
laterotrusive (or working side) contacts
Any contacts that occur on the right side during left laterotrusive movement are called (...) contacts.
mediotrusive (or non-working side) contacts
Laterotrusive contacts can occur between (...) of maxillary buccal cusps and (...) of mandibular buccal cusps or between (...) of maxillary lingual cusps and (...) of mandibular lingual cusps.
inner inclines; outer inclines; outer inclines; inner inclines
Mediotrusive contacts can only occur between (...) of maxillary lingual cusps and (...) of mandibular buccal cusps.
inner inclines; inner inclines
A (...) movement occurs when the mandible moves posteriorly from the intercuspal position.
Compared to the other movements, retrusive movement is quite small (1 or 2 mm) because it is (...).
restricted by the ligamentous structures
Any area of a tooth that contacts an opposing tooth during retrusive movement is considered to be a (...).
Posterior retrusive contacts can occur between the (...) of the maxillary teeth and the (...) of the mandibular teeth.
mesial inclines; distal inclines
How many inclines of a centric cusp can potentially provide eccentric contact with the opposing tooth?
four (mesial, distal, inner, outer)
How many inclines of a noncentric cusp can potentially provide eccentric contact with the opposing tooth?
Although CR has had a variety of definitions over the years it , it is generally considered to designate the position of the mandible when the condyles are in an (...) position.
Earlier definitions described CR as the most (...) of the condyles, which is determined mainly by the ligaments of the TMJ.
Today the term centric relation suggests that the condyles are in their most (...) in the articular fossae.
How many areas is force is applied to the cranium when the mandible is elevated?
three (each TMJ and the teeth)
In establishing the criteria for the optimum orthopedically stable joint position, the (...) of the TMJ must be closely examined.
Ligaments determine the optimum orthopedically stable joint position. True or false?
False; ligaments act as limiting structures for certain extended or border joint movements, but do not actively participate in joint function.
The articular disc determines the optimum orthopedically stable joint position. True or false?
False; the articular disc is separates, protects, and stabilizes the condyle during functional movements, but it does not determine positional stability of the joint.
The directional forces of (...) determine the optimum orthopedically stable joint position.
Muscles stabilize joints, therefore every mobile joint must have a most (...) position.
The steady reflex contraction that resides in the muscles concerned in maintaining posture.
The major muscles that stabilize the TMJs are the (...).
elevators (masseter, temporalis, medial pterygoid)
The direction of the force placed on the condyles by the masseters and medial pterygoids is (...).
Although the temporalis has fibers that are oriented posteriorly, they predominantly elevate the condyles in a (...) direction.
Tonus in the inferior lateral pterygoids positions the condyles (...).
anteriorly against the posterior slopes of the articular eminences
The very thin bone located in the (...) of the mandibular fossa is not developed to support loading, but the (...) is composed of dense bone able to withstand the forces of loading.
superior aspect; articular eminence
The complete definition of the most orthopedically stable TMJ position is when the condyles are in their most (...) position in the articular fossae, resting against the (...) of the articular fossae with (...).
superoanterior; posterior slopes; discs properly interposed
(...) force to the mandible can displace the condyle from the musculoskeletally stable (MS) position; in this position, force can be applied to the posterior aspect of the disc, inferior retrodiscal lamina, and retrodiscal tissues.
(...) movement of the mandible brings the condyles down the articular eminences, which requires contraction of the inferior lateral pterygoid; this represents a “muscle stabilized” position, but not a “musculoskeletally stable” position.
If MICP were developed in an inferoanterior position, a discrepancy would exist between the most stable (...) and the most stable (...).
occlusal position; joint position
When closure of the mandible in the MS position creates an unstable occlusal condition, the (...) feeds back appropriate muscle action to locate a more stable occlusal condition. Therefore the MS position of the joints can be maintained only when it is in harmony with a (...).
neuromuscular system; stable occlusal condition
When only right side occlusal contacts are present, activity of the elevator muscles pivot the mandible using the tooth contacts as a fulcrum; the result is an increase in joint force to the (...) TMJ and a decreased force to the (...) TMJ.
With bilateral occlusal contacts, (...) stability is achieved at the same time there is (...) stability.
Bilateral occlusal contacts maintain mandibular stability; as the number of occluding teeth increases, the force to each tooth (...).
Understanding the progression of these illustrations leads to the conclusion that the optimum occlusal condition during mandibular closure would be provided by (...).
even and simultaneous contact of all possible teeth
The criteria for optimum functional occlusion are described as
- (...) contact of all possible teeth, when
- the mandibular condyles are in their most (...) position,
- resting against the (...) of the articular eminences,
- with the discs (...).
even and simultaneous; superoanterior; posterior slopes; properly interposed
In optimum functional occlusion, the (...) position of the condyles coincides with the (...) position of the teeth.
musculoskeletally stable (CR); maximum intercuspation (MICP)
The exact contact pattern of each tooth must be more closely examined so a precise description of the optimum relationship can be derived. To evaluate this better, the (...) and (...) of force applied to each tooth needs to be closely examined.
Since the teeth are constantly receiving occlusal forces, a (...) is present between the root of the tooth and the alveolar bone to help control these forces.
periodontal ligament (PDL)
When force is applied to the tooth, the fibers support it and tension is created at the alveolar attachment; pressure stimulates bone (...), but tension stimulates bone (...).
When cusp tips contact flat surfaces, the resultant force is directed vertically through the (...); this type of force is accepted well by the periodontal ligament.
long axes of the teeth
When opposing teeth contact on inclines, the direction of force is not through the long axes of the teeth; instead, (...) are created that tend to cause (...) of certain areas of the PDL and (...) of other areas.
tipping forces; compression; elongation
If a tooth is contacted such that the resultant forces are directed (...), the PDL is quite efficient in accepting the forces and breakdown is less likely.
If a tooth is contacted in such a manner that (...) forces are applied to the supportive structures, the likelihood of pathologic effects is greater.
The process of directing occlusal forces through the long axis of the tooth.
Two methods of achieving axial loading.
- development of tooth contacts on either cusp tips or relatively flat surfaces perpendicular to the long axis of the tooth
- development of tooth contacts such that each cusp produces three contacts surrounding the cusp tip (tripodization)
The amount of force that can be generated between the teeth depends on the distance from the temporomandibular joint and the muscle force vectors; much more force can be generated on the (...) teeth than on the (...) teeth
When heavy forces are applied to an object on the posterior teeth, the mandible is capable of shifting (...) to obtain the occlusal relationship that will best complete the desired task, creating an unstable mandibular position.
downward and forward
The damaging horizontal forces of eccentric movement must be directed to the (...) teeth, which are positioned farthest from the fulcrum and the force vectors.
Since the amount of force that can be applied to the (...) teeth is less than that which can be applied to the (...) teeth, the likelihood of breakdown is minimized.
When all the anterior teeth are examined, it becomes apparent that the (...) are best suited to accept the horizontal forces that occur during eccentric movements.
The canines are best suited to accept the horizontal forces because they have the best (...) and they are also surrounded by (...).
crown/root ratio; dense compact bone
When the mandible is moved in a right or left laterotrusive excursion, and the canines contact and dissipate the horizontal forces while disoccluding or disarticulating the posterior teeth.
Many patients’ canines, are not in the proper position to accept horizontal forces and other teeth must contact during eccentric movements. In fact, only about (...)% of the general population have bilateral canine guidance.
The most favorable alternative to canine guidance, in which several of the teeth on the working side contact during the laterotrusive movement.
Any laterotrusive contacts more posterior than the (...) are not desirable because of the increased amount of force that can be created as the contact gets closer to the fulcrum (TMJ).
mesialbuccal cusp of the first molar
It is reported that (...)% of the general population have group function guidance in the 20 to 30 age group and this percentage increases to (...)% in the 50 to 60 age group, likely due to (...).
41%; 68%; canine wear
During laterotrusive movement, contacts can occur between opposing (...) as well as opposing (...) cusps on both maxillary and mandibular teeth.
During mediotrusive movement, contacts occur only between the (...) cusps of maxillary teeth and the (...) cusps of mandibular teeth.
When group function guidance is desirable, the (...) contacts are utilized, while (...) contacts are not desirable during eccentric movement.
When the mandible moves forward into protrusive contact, damaging (...) forces can be applied to the teeth.
In protrusive movement, as with lateral movements, the (...) teeth can best receive and dissipate horizontal forces, and the (...) teeth should disocclude to minimize unfavorable forces to the masticatory system.
The (...) teeth function effectively in accepting forces applied during closure of the mouth because their position in the arch is such that the force can be directed through their long axes.
The (...) teeth are not positioned well in the arches to accept heavy forces because they are normally positioned at a labial angle to the direction of closure, so axial loading is nearly impossible.
If the maxillary anterior teeth receive heavy occlusal contacts during closure, there is a great likelihood that their supportive structures will not be able to tolerate the forces and they will be displaced (...).
It may be stated that (...) teeth function most effectively in stopping the mandible during closure, whereas (...) teeth function most effectively in guiding the mandible during eccentric movements.
When the posterior teeth contact slightly more heavily than anterior teeth when the teeth are occluded in the ICP.
mutually protected occlusion
In the normal upright head position, as well as the alert feeding position (head forward approximately 30 degrees), the (...) teeth should contact more heavily than the (...) teeth.
If an occlusal condition is established with the patient reclined in a dental chair, the mandibular postural position and resultant occlusal condition may be slightly (...) oriented.
If in the upright head position or the alert feeding position the patient’s mandible assumes a slightly anterior postural position, activity of the elevator muscles will result in heavy (...) tooth contacts.
When the mouth closes, the condyles are in their most (...) position, resting against the (...) of the articular eminences with the discs (...).
superoanterior (MS); posterior slopes; properly interposed.
In the MS postion, there should be (...) contact of all posterior teeth. The anterior teeth also contact but (...) than the posterior teeth.
even and simultaneous; more lightly
All tooth contacts should provide (...) loading of occlusal forces.
When the mandible moves into laterotrusive positions, there should be adequate tooth-guided contacts on the (...) side to disocclude the (...) side immediately; the most desirable guidance is provided by the (...).
laterotrusive (working); mediotrusive (nonworking); canines
When the mandible moves into a protrusive position, there should be adequate tooth-guided contacts on the (...) teeth to disocclude all (...) teeth immediately.
In the upright head position and alert feeding position, posterior tooth contacts are (...) than anterior tooth contacts.
Which ligament limits rotational movement?
Which ligament limits maximum opening?
Which ligament limits protrusive movement?