TMD - Final Flashcards
Angle formed between the sagittal plane and
the average path of the advancing condyle as
viewed in the horizontal plane during lateral mandibular movements
Bennett angle
Imaginary anteroposterior line around which the mandible may rotate when viewed in the frontal plane
Sagittal axis
Imaginary line around which the mandible may rotate through the horizontal plane
Vertical axis
Imaginary line around which the mandible may rotate within the sagittal plane
Transverse horizontal axis
Anteroposterior curve
Spee curve
Anatomic curve established by the occlusal alignment of the teeth, beginning with the cusp tip of the mandibular canine and following the buccal cusp of the premolar and molar teeth, continuing through the anterior border of the mandibular ramus, ending with the anterior-most portion of the mandibular condyle
Spee curve
Mediolateral curve
Wilson curve
Curvature of the cusps as projected on the frontal plane expressed in both arches
Wilson curve
The curve in the lower arch = concave
The curve in the upper arch = convex
Wilson curve
Any plane parallel to the long axis of the body and at right angles to the median plane, thus dividing the body into front and back parts
Frontal plane (coronal)
Any plane passing through the body at right angles to both the median and frontal planes, thus dividing the body into upper and lower parts
Horizontal plane
Any vertical plane or section parallel to the median plane of the body that divides a body into right and left portions
Sagittal plane
The static and dynamic contact relationship between the occlusal surfaces of the teeth during function
Articulation
Form of mutually protected articulation in which the vertical and horizontal overlap of the canine teeth disengage the posterior teeth in the excursive movements of the mandible
Canine guidance
When the posterior teeth prevent excessive contact of the anterior teeth in MIP, and the
anterior teeth disengage the posterior teeth in all mandibular excursive movements
Mutually protected articulation
Multiple contact relations between the
maxillary and mandibular teeth in lateral movements on the working side
Group function
Normal occlusion or neutrocclusion
Class I
Normal anteroposterior relationship of the jaws, as indicated by correct interdigitation of
maxillary and mandibular 1st molars
Class I
Distocclusion
Class II
Mandibular dental arch is posterior to the maxillary dental arch in one or both lateral
segments; mandibular 1st molar is distal to the maxillary 1st molar
Class II
Which division of Class II?
Narrow maxillary arch and protruding maxillary incisors
Divison 1
Which division of Class II?
Normal maxillary arch with maxillary centrals and excessive vertical overlap
Division 2
Messiocclusion
Class III
Mandibular arch is anterior to the maxillary
arch in one or both lateral segments; mandibular 1st molar is mesial to the maxillary 1st molar
Class III
Mandibular incisors are usually in anterior cross bite
Class III
Range of motion of the mandible
Posselt’s envelope of motion
The shape of Posselt’s envelope varies depending on the plane, but it generally resembles what 3 things?
Beak
Shield
Diamond
mandibular movement in the sagittal plane, frontal plane, and horizontal plane (look at slides 5-7 for pics)
What are the 2 movements for mouth opening?
Rotation
Translation
Occurs in inferior join cavity
Rotation
Opening of 20-25mm
Rotation
Occurs in superior joint cavity
Translation
Opening of 25-35mm
Translation
How many mm is maximum opening?
45-55mm
How many mm is lateral movement?
10-12mm
How many mm is protrusive movement?
8-10mm
All normal, proper or characteristic movements of the mandible made during speech, mastication, yawning, swallowing, and other associated movements
Functional mandibular movements
Trauma to the periodontium from functional or
parafunctional forces causing damages to its
attachment by exceeding its adaptive and reparative capacities
Occlusal trauma
Forces acting on teeth w/ normal periodontal support
Primary occlusal trauma
Forces acting on teeth with decreased periodontal support
Secondary occlusal trauma
Disordered function like clenching/grinding
Parafunction
Parafunctional grinding of teeth
Bruxism
Oral habit of involuntary rhythmic or spasmodic non-functional gnashing, grinding, or clenching of teeth; may lead to occlusal trauma
Bruxism
The influence of the contacting surfaces of anterior teeth on tooth limiting mandibular
movements
Anterior guidance
The steepness of the lingual surfaces of max
anterior teeth determines the amount of vertical movement of the mandible
Anterior guidance
Mandibular guidance generated by the condyle and articular disc traversing the contour of the
glenoid fossa; depends on the steepness of the articular eminence
Condylar guidance
Contacts of teeth made on the side of the articulation toward which the mandible is moved during working movements
Working side contacts
Undesirable contacts of the opposing occlusal surfaces on the nonworking side (which interferes with the working side occlusal contacts)
Non-working side contacts
One of the features of ideal occlusion is absence of ____________ interferences
posterior
The modification of the occlusal form of the teeth with the intent of equalizing occlusal stress, producing simultaneous occlusal contacts or harmonizing cuspal relations
Occlusal equilibration
With the condyles in CR (musculoskeletal stable position) and the articular discs properly interposed, all possible posterior teeth contact evenly and simultaneously between centric ___________ and opposing ____________
cusp tips; flat surfaces
When excursive movements happen, laterotrusive contacts on the anterior teeth ____________ the posterior teeth
disocclude
When the mandible is protruded, contacts on the anterior teeth _______________ the posterior teeth
disocclude
Mechanical instrument that represents the
TMJs and jaws, to which maxillary and mandibular casts may be attached to simulate some or all mandibular movements
Articulator
Instrument used to record the spatial
relationship of the maxillary arch to some anatomic reference point or points (condyles
horizontal axis and one other selected anterior point) and then transfer the relationship to an articulator
Facebow
Which articulator classification?
Only vertical motion is possible
Class I
Which articulator classification?
Accepts a single static registration
Class I
Which articulator classification?
Permits horizontal and vertical motion, but does not orient the motion to TMJs
Class II
Which articulator classification?
Instrument that stimulates condylar pathways by using averages of mechanical equivalents for all or part of the motion
Class III
Which articulator classification?
Semi-adjustable
Class III
Which articulator classification?
Instrument that will accept 3D dynamic registrations, allow for orientation of the casts to the TMJs, and stimulate mandibular movements
Class IV
Which articulator classification?
Fully adjustable
Class IV
What part of the articulator?
Lateral and horizontal condylar inclination- represents the posterior determinants
Condylar guidance
What part of the articulator?
Rigid rod attached to one member contacting the anterior guide table of the opposing member; maintains vertical separation
Anterior guide pin
What part of the articulator?
Where the anterior guide pin rests to maintain VDO and influence articulator movements. It influences the degree of separation of the casts in all relationships
Anterior guide table
What part of the articulator?
Upper member holds maxillary cast and lower member holds mandibular cas
Member
What part of the articulator?
Removable metal or resin devices that attaches to the superior and inferior members of the articulator which are used to attach casts to articulator
Mounting plate
What are the skeletal components of the TMJ?
Maxilla
Mandible
Temporal bone
What are the 5 ligaments involved with the TMJ?
Collateral (discal)
Capsular
Temporomandibular
Sphenomandibular
Stylomandibular
What are the muscles of mastication involved with the TMJ?
Masseter
Temporalis
Lateral pterygoid
Medial pterygoid
Composed of dense fibrous CT; it is very slightly innervated
Disc
The articular surface of the condyle is located on the _____________ zone of the disc
intermediate
T/F: The disc maintains morphology unless destructive forces or structural changes occur in the joint
True
T/F: The morphology of the disc can be irreversibly altered, producing biomechanical changes
True
The disc acts as a _____________ bone contributing to both joint systems
non-ossified
The disc functions as a true ____________ ____________ in both joint systems
articular surface
Both joint cavities are filled with what?
Synovial fluid
Synovial fluid serves as a ___________ btwn the articular surfaces during function
lubricant
Since the articular surfaces are ___________, the synovial fluid acts a medium for providing _____________ requirements to these tissues
non-vascular; metabolic
Loose CT that attaches to the posterior part of the disc
Retrodiscal tissue
Highly vascularized and innervated
Retrodiscal tissue
What nerve provides innervation to the TMJ?
Trigeminal nerve V3
(auriculotemporal nerve)
T/F: The TMJ is an extremely complex joint system
True
T/F: Both TMJs connect to the mandible, so they can’t act without influencing the other
True
What do the following describe?
- Tissues that surround the inferior synovial cavity (condyle + articular disc; rotational)
- Condyle-disc complex functioning against the surface of the mandibular fossa (translation)
2 joint systems of the TMJ
What is the disc and its attachment to the condyle called?
Condyle-disc complex
What is responsible for rotational movement in the TMJ?
Condyle-disc complex
___________ occurs in this superior joint cavity btwn the disc and mandibular fossa
Translation
The articular surfaces of the joint have no structural attachment or ________, yet contact must be maintained constantly for ________ __________
union; joint stability
What is stability of the TMJ maintained by?
Constant activity of muscles
What is the only structure capable of retracting the disc posteriorly on the condyle?
Superior retrodiscal lamina
Which muscle is attached to the anterior border of the disc?
Superior lateral pterygoid
When the superior lateral pterygoid is active, which way are the fibers pulled?
Anterior + medially
Which muscle attaches to the neck of the condyle?
Lateral pterygoid
What muscle is inactive when the inferior lateral pterygoid is protracting the condyle forward?
Superior lateral pterygoid
Which muscle activates during mandibular closure?
Superior lateral pterygoid
The mechanism by which the disc is maintained with the translating condyle is dependent on what?
Morphology of disc and interarticular pressure
What are the 3 important principles of biomechanics of the TMJ?
- Ligaments do NOT actively participate in normal function of TMJ
- Ligaments elongate (they do NOT stretch!)
- Articular surfaces of the TMJ must maintain constant contact (produced by muscles of mastication (elevator))
Occurs as movement within the inferior cavity of the joint; between the superior surface of the condyle and the inferior surface of the articular disc
Rotation
Rotation occurs in all 3 planes. Name them
Horizontal
Sagittal
Frontal
20-25 mm
Rotation
Occurs when the mandible moves forward; it happens within the superior cavity of the joint between the superior surface of the articular disc and the inferior surface of the articular fossa
Translation
40-60 mm max opening
Translation
Collective term embracing several clinical problems that involve the masticatory
musculature, the TMJ and associated structures or both.
TMD
Identified as a major cause of non-dental pain
TMD
What are the most common symptoms of TMD?
Pain
TMJ sounds
Limited/asymmetric mandibular movements
Headaches, earaches, jaw pain, facial pain
What often coexists with other craniomandibular and orofacial pain conditions?
TMD
What % of people have at least 1 sign of joint dysfunction?
40-75%
What % of people have at least 1 symptom of TMD?
33%
What % of people have joint sounds?
50%
What % of people have mouth opening limitations?
5%
T/F: Adults experience more TMD problems than children
True
Who experiences more TMD problems: women or men?
Women
(studies show 3:1 and 9:1)
Who seeks treatment for TMD more often: women or men?
Women
T/F: It is estimated that only 3.6-7% of people with TMD need treatment
True
Factors that increase the risk of TMD
Predisposing factors
Factors that cause the onset of TMD
Initiating factors
Factors that interfere with healing or enchance progression of TMD
Perpetuating factors
What was labeled “Important” for the etiology of TMD?
Long term successful management
Any force applied to mastication structures that exceeds normal function load
Trauma
What are the 3 types of trauma?
Direct
Indirect
Micro
Which type of trauma?
Direct blow to structures
Produces injury via impact
Inflammation
Structural failure
Loss of function
Onset occurs within 24-72 hrs of the trauma
Direct
Which type of trauma?
Sudden blow w/o direct contact to affected structures
Whiplash injury
Pathways of pain from cervical area to trigeminal area
Not uncommon to see symptoms of TMD following injury to neck w/o direct trauma to face or jaw
Indirect
Which type of trauma?
Sustained and repetitious adverse loading of the masticatory system through postural imbalance or parafunctional habits
Micro
Which type of trauma?
Intensity and frequency of parafunctional jaw activity may be exacerbated by stress and anxiety, sleep disorders, and meds
Micro
Which type of trauma?
Intense and persistent parafunction can also occur in pts w/ neurologic disorders such as cerebral palsy, orofacial dyskinesia, and epilepsy
Micro
Which type of trauma?
Related to postural habits
Micro
What are the 2 main anatomic factors that play a role in TMD?
Skeletal relationships
Occlusal relationships
Skeletal malformations, arch discrepancies, past injuries to teeth, steepness of articular eminence
Skeletal relationships
T/F: Literature does not support the role of occlusion in etiology of TMD
True!
Associated w/ more joint sounds and muscle tenderness
Overbite
Associated w/ condylar changes and rheumatoid arthritis
Anterior open bite
Associated w/ TMD symptoms and osteoarthritic changes
Overjet
More common in TMD patients
Unilateral posterior crossbite
Associated w/ internal derangement and osteoarthritc changes
Missing posterior teeth
Systemic factors of TMD need to be managed in cooperation with a __________
physician
What are the 7 pathophysiologic factors of TMD?
Degenerative
Endocrine
Infectious
Metabolic
Neurologic
Rheumatologic
Vascular disorders
Include individual, interpersonal, and situational variables that impact the pt’s capacity to function adaptively
Psychosocial factors
May alter the pt’s perception and tolerance of physical symptoms
Psychosocial factors
What are 2 psychosocial factors of TMD?
Anxiety
Depression
What is chronic TMD defined by?
More than 4 months in pain
T/F: Clinical reports suggest that the psychologic conflicts and emotional distress of preexisting psychiatric conditions may contribute to the etiology and exacerbation of TMD conditions
True
The use of what 3 things can contribute to the chronicity of many TMD pts?
Alcohol
Tranquilizers
Narcotics
Upper facial skeleton
Maxilla
Made up of 2 maxillary bones fused at midpalatal suture
Maxilla
Has dentoalveolar support and bony attachment to skull
Maxilla
Composed of body and ramus
Mandible
Lower facial skeleton
Mandible
Has dentoalveolar support, but no bony attachment to the skull
Mandible
Has muscle and ligament suspension and is mobile
Mandible
What are the 2 processes of the ramus of the mandible?
Coronoid process
Condylar process
Supports the mandible at articulation with the cranium
Temporal bone
Portion of the mandible that articulates with cranium bilaterally
Mandibular condyles
Made of condyle and condylar neck
Condylar process
Has medial and lateral poles
Condyle
What are the dimensions of the mandibular condyles?
Medio-lateral (18-23 mm)
Antero-posterior (8-10 mm)
Site of mandibular condyle articulation
Glenoid fossa
Oval depression on inferior aspect of temporal bone
Glenoid fossa
Anterior to external auditory meatus
Glenoid fossa
Forms anterior limit of the mandibular fossa
Articular eminence
Convex prominence of thick dense bone
Articular eminence
The articular eminence has variable degree of _________, which dictates the ____________ path of mandibular condyle
convexity; protrusive
Complex diarthrodial joint with 2 functional movements
TMJ
The TMJ has ____________ movement in the __________ compartment between the mandibular condyle and articular disc
rotational; inferior
The TMJ has ____________ movement in the ___________ compartment between the disc and temporal component
translational (sliding); superior
Divides the TMJ space into superior and inferior compartments
Articular disc
The ____________ compartment is between the disc and mandibular fossa
superior
The ____________ compartment is between the disc and condyle
inferior
What type of CT is the articular disc made up of?
Avascular dense fibrous CT
What shape is the articular disc?
Biconcave + oval
Has anterior and posterior bands with an intermediate zone in between
Articular disc
Has medial and lateral attachments
Articular disc
Posterior attachment zone
Retrodiscal tissue
Known as bilaminar zone
Retrodiscal tissue
Loose neurovascular CT bordered by 2 lamina
Retrodiscal tissue
What is the attachment for the superior lamina of the retrodiscal tissue?
Temporal posterior attachment
What is the attachment for the inferior lamina of the retrodiscal tissue?
Condylar posterior attachment
Fibrous, non-elastic membrane surrounding the TMJ
TMJ capsule
TMJ ligaments are thick, fibrous tissue that limit what?
Joint movement
Function is to create a seal for joint space and provide stability
TMJ capsule
Limits separation and range of movement of articular components; prevents tissue damage and lateral + medial dislocation of joint
TMJ capsule
Muscles of mastication maintain ___________ position of ____________ at rest against grvity
postural; mandible
TMD frequently involves pain in which muscles?
Muscles of mastication
Which accessory muscles of mastication?
Digastric
Stylohyoid
Mylohyoid
Geniohyoid
Suprahyoid
Which accessory muscles of mastication?
Omohyoid
Sternohyoid
Sternothyroid
Thyrohyoid
Infrahyoid
What are the other 3 accessory muscles of mastication? (not in suprahyoid or infrahyoid categories)
Platysma
Orbicularis oris
Buccinator
Which muscle?
Quadrilateral in shape, covers lateral aspect of ramus
Masseter
Which part of masseter?
Origin = inferior border of anterior 2/3 of zygomatic arch
Insertion = angle of mandible
Superior part of masseter
Which part of the masseter?
Actions:
Elevation, bilateral
Excursion, ipsilateral
Protrusion, bilateral
Superior part of masseter
Which part of masseter?
Origin = inferior border of posterior 1/3 and internal aspect of zygomatic arch
Insertion = lateral superior ramus
Deep head of masseter
Which part of masseter?
Actions:
Elevation, bilateral
Excursion, ipsilateral
Retrusion, bilateral
Deep head of masseter
Which muscle?
Fan shaped
Temporalis
Which muscle?
Origin = inferior temporal line of skull, temporal fossa
Insertion = coronoid process
Temporalis
Which muscle?
Actions:
Elevation, bilateral
Retrusion (posterior fibers)
Temporalis
Which part of medial pterygoid?
Origin = pterygoid fossa btwn lateral and medial pterygoid plates
Deep head of medial pterygoid
Which part of medial pterygoid?
Origin = pyramidal process of palatine bone, maxillary tuberosity
Superficial head of medial pterygoid
Which muscle?
Insertion = angle of mandible medial ramus
Medial pterygoid
Which muscle?
Actions:
Elevation, bilateral
Contralateral excursion, unilateral
Protrusion, bilateral
Medial pterygoid
Which part of lateral pterygoid?
Origin = greater wing of sphenoid bone, inferior aspect
Insertion = TMJ capsule, disc, anterior condylar neck
Superior head of lateral pterygoid
Which part of lateral pterygoid?
Action:
Stabilize disc position
Superior head of lateral pytergoid
Which part of lateral pterygoid?
Origin = lateral pterygoid plate of sphenoid bone
Insertion = condylar neck
Inferior head of lateral pterygoid
Which part of lateral pterygoid?
Actions:
Protrusion, bilateral
Contralateral excursion, unilateral
Depression, bilateral
Inferior head of lateral pterygoid
