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Occlusion 6800 Final Examination Review.ppt

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					      Occlusion 6800
Final Examination Review

  For the exam to be administered on:
         Tuesday, May 15, 2012
                 Lab 30
           2:00 pm – 4:00 pm


    Charles J. Arcoria, DDS, MBA
        Associate Professor
      Exam Construction

•   There are fifty questions on the examination.
•   It is comprehensive.
•   Twenty questions will be over the material,
    prior to the mid-term examination.
•   Thirty questions will be over the material after
    the mid-term examination.
•   Multiple choice, five answer possibilities for
    each question.
        Basic Structures of the
       Temporomandibular Joint



                                                                   Articular Disc



                Condyle
>Mandibular/Glenoid Fossa
>Articular eminence: 1) Posterior slope, 2) Steepness/flatness guides movement
>Synovial cavities: 1) Joint lubrication, 2) boundary lubrication from motion
        The Temporomandibular
                Disc
• Fibrous connective
  tissue
• Interface between
  bones, somewhat
  pliable
• Bi-concave shape
• Collateral ligaments
• No Innervation
• No Vascularization
Muscles of Mastication
       Actions and Purposes
•   Produce smooth movement in a variety of directions
•   Movement is limited by strategically placed
    ligamentous structures
•   Bony structures are starting, guiding and sometimes
    end points of movement driven by the musculature
•   Normal activity does not cause spasms
•   Occlusal interferences may lead to spasms
•   Opening, closing and lateral movement are most
    notable
•   Main driver of the Craniomandibular apparatus
•   There are 4 main muscles of mastication and several
    other accessory or supplemental muscles of
    mastication
•   Important to differentiate between normal function
    and parafunctional activities
  Limitation of Movement with TM Ligament




Designed to limit the pure hinge axis rotation movement. Full length occurs at
15-20 mm of opening, which has a pivot point at which translation commences.
                Lateral Pterygoid

• Inferior belly
   – Slow muscle fibers
   – Origin: Lateral surface of the
     lateral pterygoid plate
   – Insertion: Neck of the
     condyle
   – Active during opening and
     protrusion and lateral
     movements
  Anesthetized Lateral Pterygoid Muscle




                          X




If the right lateral pterygoid is anesthetized and the patient is instructed to open
      their mouth, the mandible will deviate or move to the same side as the
                 anesthetized lateral pterygoid muscle is located on.
Mandibular Movement is Controlled
     by the Lateral Pterygoid
• Lateral Pterygoid Contracts
   – Inferior belly
• Condyle moves anteriorly
   – Down the slope of the articular
     eminence
• Mandibular movement produced:
   – Movement to the opposite side (I.e., the
     left lateral pterygoid will cause
     movement to the right side
Muscles involved in seating
   Condyles in Fossa
Medial Pole of Condyle and Medial Pterygoid Muscle




  The relationship of the medial pole of the condyle and the medial pterygoid
  muscle on one side establishes the mid-most position of the mandible at centric
  relation. The normal curve of occlusion is possible because the medial pole
  prevents the mandibular posterior teeth from moving horizontally toward the
  midline. As a result, mandibular lateral translation is impossible from the fully
  seated positions of the condyle in the fossa.
         Activities During Normal Closure
Muscles that contract:
>Temporalis anterior fibers
>Medial pterygoid
>Masseter


Condylar action that is occurring:
>Retrusion (posteriorly oriented
translation) & hinge axis closure


Muscles that are relaxed:
>Suprahyoids
>Lateral pterygoid
    Early Jaw Opening Movement
• Lateral Pterygoid Contracts
   – Inferior belly
• Condyle moves anteriorly
   – Down the slope of the articular
     eminence
• Condyle is translating
• Articular Disc moves with
  Condyle
   – Superior belly of lateral pterygoid
     will minimally contract
   – Superior retrodiscal tissues will
     exhibit a minimal amount of tautness,
     in response to the anterior movement
     of the disc
   – Thinnest, avascular portion of the
     articular disc articulates between the
     condyle and the temporal bone
Potential Temporalis Spasm
             •   Action of the Temporalis:
             •   Elevates mandible, retracts
                 and positions mandible,
                 clenches teeth

             •   Spasm Activity:
             •   A severe spasm of the right
                 temporalis muscle that
                 overrides the action of the
                 other closing muscles will
                 showcase the mandible
                 moving to the same side
                 (right)
Single Antagonist Contact in
     Opposing Arches




 In an ideal intercuspal relation, the maxillary third molars and mandibular
       central incisors have a single antagonist in the opposing arch.
                 Static Occlusion Contacts
                  In the Intercuspal Position




                                                                                     X
The lingual cusps of the permanent mandibular first premolar and mandibular
    second molar will articulate in the intercuspal position as follows:
•   The lingual cusp of the first premolar will articulate with NO maxillary tooth entity
•   The distolingual cusp will articulate in the lingual groove between the mesiolingual and
    distolingual cusps of the maxillary second molar
Key to Occlusion Minimums

•   Angle’s Class I Occlusion:
     – ML cusp of Maxillary 1st
       molar occludes in the
       central fossa of Mandibular
       1st molar

     – MF cusp of Maxillary 1st
       molar occludes in the MF
       groove of Mandibular 1st
       molar

     – Cusp tip of maxillary canine
       articulating with the facial
       embrasure between the
       mandibular canine and first
       premolar
               Static Occlusion Contacts
                In the Intercuspal Position




The distofacial cusp of the permanent maxillary first molar will articulate in the
    intercuspal position in the facial embrasure between the mandibular first and
    second molars.
Moving Occlusion Pathway – Non-Working




   Left lateral Movement
                                              Right Side Pathway
    For left lateral movement, the lingual cusp of the maxillary right
     second premolar will travel over the mesiofacial cusp of the
                         mandibular first molar.
Moving Occlusion Pathway - Working




Left lateral Movement
                                          Right Side Pathway
    During left lateral movement, the distolingual cusp of the
 maxillary left second molar passes through the lingual embrasure
         between the mandibular second and third molars.
 Moving Occlusion Pathway – Specific Anatomy




         Right lateral Movement


                                                   Right Side Pathway
During right lateral movement, the mesial cuspal ridge of the mesiolingual
 cusp of the maxillary right first molar passes over the triangular ridge of
           the mesiolingual cusp of the mandibular first molar.
        Protrusive Movement




 During a protrusive movement of the mandible, the mesial marginal ridge of
the maxillary first molar would contact the mesiofacial cusp of the mandibular
                                  first molar
           Know the Moving Occlusion Booklet




Left lateral non-working (mediotrusive); right side
                                                                Non-functional movement; right side




      Right lateral non-working (mediotrusive); left side   Left lateral working (protrusive); left side
Border Movements in Sagittal Plane
                                 Legend:
                    MI           CR = Centric Relation
                         E-T-E   MI = Maximum Intercuspation
                                 E-T-E = Edge to Edge Incisal
               CR                MP = Maximum Protrusion Point
                           MP
          HA                     MOA = Maximum Opening Arc
                                 MO = Maximum Opening Point
                          RP     HA-MO = Hinge Axis to Maximum
      HAT
                         CL                 Opening
                                 HAT = Hinge Axis Terminating
  HA-MO                  MOA            Point
                                 HA = Hinge Axis Arc
                                 RP = Rest Position or Postural
                                      Position of the Mandible
               MO                CL = Chewing Loop
Protrusive Movement

             Protruded contact of
             Maxillary and
             Mandibular Incisors.
             Mandible is continuing
             to protrude forward
             from Edge-to-Edge
             Incisal, maintaining
             some type of tooth
             contact throughout. The
             condyles have translated
             forward, in an anterior
             position.
Immediate & Progressive Sideshift
Immediate Sideshift: When the lateral
translation movement occurs before the
condyle translates from the fossa.
Progressive Sideshift: The progressive
Lateral Translation movement of the
condyle in a downward, forward, and
inward (medial) direction. It occurs during
the middle to late stage of lateral movement.
       The more severe the immediate
   sideshift, the shorter the posterior cusps
   and the wider are the fossae & grooves.
  Immediate Sideshift + Progressive Sideshift =
             Bennett Movement
                 MI to CR Effects




                                                                 PRP
ICP (MI)                   CR
                                              Overlap
Moving the mandible from a maximum intercuspal position to a retruded
contact position in centric relation, in a patient with a typical slide, usually
results in increased occlusal vertical dimension, increased horizontal overlap,
decreased vertical overlap, and an altered physiological rest position.
     Immediate Sideshift Measurement
                                                       Non-Working,
                                                      Translating, or
                                                      Orbiting Condyle




                                                     L


                                                   Left Side
Mandibular lateral translation (immediate side shift) will characterize the
distance between the medial pole of the condyle and the medial wall of the
fossa on the non-working side.
           Frontal Plane
      Rest Position (RP) & Chewing Loop (CL)
        MI        ELL
ERL                           Legend:
                              MI = Maximum Intercuspation
             RP
                              ELL = Extreme Left Lateral
                              MO = Maximum Opening
                              CL = Chewing Loop
                              RP = Rest Position
             CL
                              ERL = Extreme Right Lateral




             MO
           Horizontal & Vertical Factors
1. Condylar Guidance Angle (fixed)
2. Anterior Guidance (variable)
3. Nearness of cusp to the Controlling Factors (variable)
4. Plane of Occlusion (variable)
5. Curve of Spee (variable)
6. Mandibular Lateral Translation aka Bennet Movement (fixed)
7. Timing of MLT: (a) Immediate Sideshift aka Bennet Shift & (b) Progressive Sideshift (fixed)



                    •Cusps & ridges have vertical (height) and horizontal (incline/slope)
                    •Cusps & ridges have vertical (height) and horizontal (incline/slope)
                    dimensions.
                    dimensions.


                    •Fossae & grooves also have vertical (depth) & horizontal (width &
                    •Fossae & grooves also have vertical (depth) & horizontal (width &
                    direction) dimensions.
                    direction) dimensions.


         How the mandible moves vertically and horizontally
         How the mandible moves vertically and horizontally
          determines the occlusal morphology of the teeth.
          determines the occlusal morphology of the teeth.
     Immediate Sideshift Measurement
                                    Non-Working,
 R: Working or                     Translating, or
 Rotating Condyle                  Orbiting Condyle


                                                   L



              R


The medial wall of the non-working condyle can affect the height of the maxillary
lingual cusps and mandibular facial cusps on the non-working side. The working
side cusps are more affected by the canine rise on that working side.
   Anterior Guidance Influence
• An increase in Vertical Overlap results in more of a vertical
  component to mandibular movement and steeper posterior
  cusps.
• An increase in Horizontal Overlap (diminished anterior
  guidance angle) results in less vertical displacement of the
  mandible and flatter posterior cusps.
• Variations in the anatomy of the TMJ’s and/or the anterior
  teeth will lead to changes in the movement pattern of the
  mandible.
• The occlusal morphology of posterior teeth must be in
  harmony with their opposing teeth during eccentric
  mandibular movements.
• The exact morphology of a posterior tooth is influenced by
  the pathway it travels across its opposing tooth or teeth.
• These factors influence wax-ups of restorations
    Occlusal Determinant Factors

                    Point “X” is equidistant from the controlling
                    factors and is controlled equally by each.
                  The nearer a point is to a controlling
                  factor, the more its movement is
                  controlled by that factor.
                                                                    Plane of Occlusion


                                                                         Fossae width and depth



•The nearer the tooth to the TMJ, the more the joint anatomy influences the eccentric movement
•The nearer a specific tooth is to the anterior teeth, the more the anatomy of the anterior teeth
influence its eccentric movement.
•The width of fossae and the direction of grooves are horizontal considerations of occlusal
morphology
•The depth of fossae and the height of cusps are vertical considerations of occlusal morphology
•The occlusal forces placed on posterior teeth are best distributed in maximum intercuspation
•As the plane of occlusion approaches parallelism with the articular eminence, the shorter the
posterior cusps will need to be in order to avoid collision
          Tall vs. Short Cusp Height Allowances




Articular Eminence




                              Non-Working
                              Cusp Heights
   Curve of Spee
                                                       Medial Wall Distance
>A steep condylar guidance angle will allow for taller cusps
>The more acute the Curve of Spee, the shorter the cusps will need to be to avoid
collisions
>The greater the distance between the orbiting condyle and the medial wall, the greater
the amount immediate sideshift
>The greater the amount of the immediate sideshift, the shorter the cusps will need to be
>The greater the amount of the immediate sideshift, the wider the grooves will need to be
Variable vs. Fixed Determinants

 1. Condylar Guidance Angle (fixed)
 2. Anterior Guidance (variable)
 3. Nearness of cusp to the Controlling Factors (variable)
 4. Plane of Occlusion (variable)
 5. Curve of Spee (variable)
 6. Mandibular Lateral Translation aka Bennet Movement (fixed)
 7. Timing of MLT: (a) Immediate Sideshift aka Bennet Shift & (b)
 Progressive Sideshift (fixed)
   Non-Adjustable Articulators
•• No adjustments are possible
    No adjustments are possible
•• Allow for eccentric movements within limitations of the
    Allow for eccentric movements within limitations of the
   instrument
    instrument
•• Cannot duplicate a patient’s specific movements
    Cannot duplicate a patient’s specific movements
•• Sometimes referred to as a “Barn door hinge”
    Sometimes referred to as a “Barn door hinge”
•• Closed occlusal contact position only one that is
    Closed occlusal contact position only one that is
   reproducible (MI or ICP)
    reproducible (MI or ICP)
•• Arbitrary mounting procedures used to locate & fix the
    Arbitrary mounting procedures used to locate & fix the
   casts
    casts
•• Casts are located equidistant between the Mx & Mn
    Casts are located equidistant between the Mx & Mn
   components of the articulator
    components of the articulator
•• Casts are held together with the teeth in maximum
    Casts are held together with the teeth in maximum
   intercuspation
    intercuspation
•• Any bite registration material that allows the teeth to
    Any bite registration material that allows the teeth to
   separate will result in an inaccurate replication of the ICP
    separate will result in an inaccurate replication of the ICP
           Facebow Device
•• Used to orient & mount the maxillary cast
   Used to orient & mount the maxillary cast
   on the articulator relative to the TMJ’s
   on the articulator relative to the TMJ’s
•• Utilizes three (3) distinct reference points
   Utilizes three (3) distinct reference points
   (two posterior & one anterior) …
   (two posterior & one anterior) …
       Posterior: hinge axis of each condyle
        Posterior: hinge axis of each condyle
       Anterior: arbitrary- established by
        Anterior: arbitrary- established by
                   manufacturer
                    manufacturer
•• Transfers the intercondylar distance of the
   Transfers the intercondylar distance of the
   patient to the articulator
   patient to the articulator
•• Is it not used to mount the mandibular cast
   Is it not used to mount the mandibular cast
    Dominant Factors Regarding
      Mandibular Movements




•   Anterior Guidance
•   Condylar Guidance Angle
•   Immediate Sideshift
    When a patient has adequate & immediate anterior guidance, these tooth
    When a patient has adequate & immediate anterior guidance, these tooth
            contacts dominate and control mandibular movement.
             contacts dominate and control mandibular movement.
Wide Intercondylar Distance on a Patient – Using a Non-adjustable Articulator




                                            Occlusal Collisions will
                                            likely occur if you use a
                                           non-adjustable articulator


 One of the primary reasons for using an articulator is to minimize the
••Oneof the primary reasons for using an articulator is to minimize the
need for intraoral adjustments
 need for intraoral adjustments
••The more sophisticated the instrument, the less likelihood for the need of
  The more sophisticated the instrument, the less likelihood for the need of
adjustments
 adjustments
••When utilizing a fully-adjustable articulator, the chair time to transfer
   When utilizing a fully-adjustable articulator, the chair time to transfer
information from the patient to the articulator makes it impractical for
 information from the patient to the articulator makes it impractical for
single units
 single units
••The more complex the case, the more complex the articulator
  The more complex the case, the more complex the articulator
Location of Non-Working Interferences - Maxilla

                                      >Facial
                                      inclines of the
                                      maxillary
                                      posterior
                                      lingual cusps




                                       >Parallel to
                                       the distal
                                       oblique
                                       groove – Max
                                       1st Molars
        Class III Crossbite




In an acquired Class III crossbite relationship, as the
   mandible retrudes, the maxillary central incisor
 contacts the mandibular central and lateral incisors
 Non-Working Interferences




  Non-working interferences are portrayed as
traveling in an oblique direction, parallel to the
 Distal Oblique Groove of the Maxillary Molars
Working Side Interferences




   >Lingual inclines of      >Lingual inclines of
   the maxillary posterior   the maxillary
   facial cusps              posterior lingual
                             cusps
Protrusive Interferences




  >Distal marginal ridges of the mandibular posterior teeth
How is it possible to find a five cusp
   Mandibular Second Molar?




        >Lingual           >Parallel to the
        inclines of the    distofacial
        mandibular         developmental
        posterior facial   groove – Mand
        cusps              1st Molars
         Working Interferences




 Mesiolingual cusps of the maxillary molars travel in a
     lingual direction, parallel to the lingual groove of
mandibular molars. Contact might occur on the triangular
  ridges of the lingual cusps of the mandibular molars.
 Muscles Involved with Forward Displacement of the Mandible




Lateral Pterygoids and Posterior/Middle Temporalis
   Lateral Displacement of the Mandible
 Muscles affected on Opposite vs. Same side




Summation: “A” & “C” contacts will display Medial & Lateral Pterygoid
 contracture on the opposite side. The Masseter and Posterior/Middle
   Temporalis are contracting on the same side of the interference.
 Closure Interference – Muscle Responses
       Deviation to the Opposite Side of the Interference
      Maxillary Lingual to Mandibular Facial Cusp Contact
                     Premature “B” Contact




  Summation: “B” contacts will display Medial & Lateral Pterygoid
 contracture on the same side. The Masseter and Posterior/Middle
Temporalis are contracting on the opposite side of the interference.
      Basic Terminology of TMD Function & Dysfunction
Internal Derangement = a deviation in position of form of the tissues within the capsular
apparatus of the temporomandibular joint, essentially giving rise to an abnormal relationship of
the articular disc to the condyle, mandibular fossa and/or articular eminence.
Intracapsular TMD = problems and clinical conditions associated with the temporomandibular
joint that are contained within the capsular apparatus (i.e., the immediate joint tissues)
Extracapsular TMD = problems and clinical conditions associated with the
temporomandibular joint that are outside the joint (i.e., the muscles of mastication and many
ligaments)
Myofascial Pain Dysfunction Syndrome = is used to describe a number of different common
painful states characterized by the presence of trigger points within the affected muscle(s).
This syndrome is a common source of low-back pain, neck pain, shoulder pain, chest pain,
and rib pain
Articular Disc Displacement = physical dislocation or displacement of the articular disc,
either anterior to or posterior to the head of the condyle
Reciprocal Clicking = a popping sound from the articular disc, exhibited as a forceful
“jumping” back or “snapping” over the head of the condyle, usually occurring during the early
opening or late closing condylar movement
Closed Lock = an internal derangement of the temporomandibular joint in which the articular
disc is dislocated anteriorly and usually medially to the condyle. The articular disc is physically
incapable of reducing or receding posteriorly into position on the head of the condyle.
Differential Diagnosis = The determination of one of two or more conditions a patient is
suffering from by systematically comparing and contrasting their historical and clinical findings.
 Terminology
for internal derangements




   Normal


   Displacement


   Dislocation
                      Disc Dislocation
                       without reduction



n   “Closed lock”                                  1


n   Disc positioned
                                               8       2
    anteriorly
                                           7               3
n   Realignment does not
                                               6       4
    occur

n   No joint noises                                5

n   Limited opening
Differential Diagnosis of Clicking
>Early opening click = occurs at initiation of the translation of the
   condyle(s)
>Late opening click = occurs just prior to termination of opening in
   patients with anteriorly displaced disks
>Deviation in form = aberrant structure of the articular disc
>Partial disc displacement = portion of the articular disc that is
   displaced to the anterior
>Disc displacement with reduction = generic displacement of
   the articular disc at rest, which resolves upon mandibular opening
>Disc displacement without reduction = generic displacement
   of the articular disc at rest, which does not resolve upon mandibular
   opening
Final Exam Review


      The End

				
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