Docstoc

Occlusal Interferences and Muscle Responses

Document Sample
Occlusal Interferences and  Muscle Responses Powered By Docstoc
					Occlusal Interferences and Muscle Responses



   Fundamentals of Occlusion & Articulation




                       Charles J. Arcoria, DDS, MBA
                             Adjunct Instructor




    Slides adapted from Dr. Peter Neff’s Manual: “Occlusion and Function”
Objectives and Goals of this Lecture:

1. Understand the location of occlusal prematurities
   during normal closure
2. Recognize the locations of working side premature
   occlusal contacts
3. Recognize the locations of non-working side
   premature occlusal contacts
4. Recognize the locations of protrusive premature
   occlusal contacts
5. Recognize the condylar positions as a result of either
   working or non-working premature occlusal contacts
6. Identify which muscles of mastication are affected by
   working, non-working, and protrusive premature
   occlusal contacts.
7. Know which side that the mandible deviates or
   moves towards whenever a working, non-working, or
   protrusive occlusal prematurity is present
 Canine Guidance – The Gold Standard
No Working or Non-Working side interferences are observed
           Occlusal Pathways
Working, Non-Working and Protrusive Pathways, determine the direction of
 ridges and grooves on the occlusal surfaces and the placement of cusps.




                                      Laterotrusive Pathway
                                           (Mandible moving away from midline)




                 Mediotrusive Pathway
                    (Mandible moving toward the midline)
 Nature of Occlusal Prematurities

1. These are recorded and recognized as a
   “high” contact, before the patient closes all
   the way into Maximum Intercuspation
2. First tooth contact in Centric Relation is a
   good example of an occlusal prematurity
3. The term prematurity implies that the contact
   is either on an incline or is in an area that is
   not considered stable (for the teeth and/or
   the condyles)
4. None of these contacts are proper Maximum
   Intercuspation occlusal contacts.
5. The mandible can be displaced anteriorly
   and/or laterally.
 Forward Displacement of Mandible




Contact occurs on posterior teeth causing
 the mandible to be anteriorly displaced
      Possible Occlusal Contact Areas
      Causing Forward Displacement




“MUDL” Occlusal Prematurity:    First tooth contact in centric
   Mesial inclines of Uppers     relation is a good example
prematurely contacting Distal
  inclines of Lowers causing
 anterior displacement of the
           mandible
   Lateral Displacement of Mandible




Premature contact causing displacement of the
  mandible to either the left or the right side
          Possible Occlusal Contact Areas
           Causing Lateral Displacement




    “C” Contact               “A” Contact                “B” Contact


“A” Contact = lingual inclines of maxillary facial cusps contacting facial
inclines of mandibular facial cusps

“B” Contact = facial inclines of maxillary lingual cusps contacting lingual
inclines of mandibular facial cusps

“C” Contact = lingual inclines of maxillary lingual cusps contacting facial
inclines of mandibular lingual cusps
             Working Side Occlusal Interferences
Potentially observed on the following surfaces:
>Lingual inclines of the maxillary posterior facial cusps
>Facial inclines of the mandibular posterior facial cusps
>Lingual inclines of the maxillary posterior lingual cusps
>Facial inclines of the mandibular posterior lingual cusps




      Initial Working Interference

                                                                    Working
                                                             interferences usually
                                                                 cause lateral
                                                              displacement of the
                                                                    mandible
         Continuation in a slide
Location of Working Interferences - Mandible


                                     >Facial inclines
                                     of the
                                     mandibular
                                     posterior facial
                                     cusps




                                     >Facial
                                     inclines of the
                                     mandibular
                                     posterior
                                     lingual cusps
Location of Working Interferences - Maxilla



                                 >Lingual inclines of
                                 the maxillary posterior
                                 facial cusps




                                  >Lingual inclines of
                                  the maxillary
                                  posterior lingual
                                  cusps
                      Non-Working Interferences
Potentially observed on the following surfaces and features:
>Lingual inclines of the mandibular posterior facial cusps
>Facial inclines of the maxillary posterior lingual cusps
>Parallel to the distofacial developmental groove – Mand 1st Molars
>Parallel to the distal oblique groove – Max 1st Molars




                                                                          Non-Working
                                                                      interferences usually
                                                                          cause lateral
                                                                       displacement of the
                                                                             mandible
Location of Non-Working Interferences - Mandible


                                       >Lingual
                                       inclines of the
                                       mandibular
                                       posterior facial
                                       cusps




                                       >Parallel to the
                                       distofacial
                                       developmental
                                       groove – Mand
                                       1st Molars
Location of Non-Working Interferences - Maxilla


                                     >Facial
                                     inclines of the
                                     maxillary
                                     posterior
                                     lingual cusps




                                      >Parallel to
                                      the distal
                                      oblique
                                      groove – Max
                                      1st Molars
                        Protrusive Interferences
Potentially observed on the following surfaces and features:
>Distal marginal ridges of the mandibular posterior teeth
>Mesial marginal ridges of the maxillary posterior teeth
Location of Protrusive Interferences - Mandible




                                        >Distal
                                        marginal
                                        ridges of
                                        the
                                        mandibular
                                        posterior
                                        teeth
Location of Protrusive Interferences - Maxilla




                                    >Mesial
                                    marginal ridges
                                    of the maxillary
                                    posterior teeth
       Table of Occlusal Prematurities

       Working                   Non-Working                       Protrusive
>Lingual inclines of the       >Lingual inclines of the       >Distal marginal ridges of
maxillary posterior facial     mandibular posterior facial    the mandibular posterior
cusps                          cusps                          teeth
>Facial inclines of the        >Facial inclines of the        >Mesial marginal ridges of
mandibular posterior facial    maxillary posterior lingual    the maxillary posterior teeth
cusps                          cusps
>Lingual inclines of the       >Parallel to the distofacial
maxillary posterior lingual    developmental groove –
cusps                          Mand 1st Molars
>Facial inclines of the        >Parallel to the distal
mandibular posterior lingual   oblique groove – Max 1st
cusps                          Molars
Premature Contact Affecting all Muscles of Mastication
Normal Closure – Muscles Involved


                    Mandibular Closure from Maximum
                    Opening:

                    >Anterior Temporalis
                    >Medial Pterygoid
                    >Masseter
                    >Relaxation of accessory muscles




                    Mandibular Closure close to
                    Maximum Intercuspation:

                    >Posterior & Middle Temporalis
                    >Relaxation of inferior and superior
                    belly of the Lateral Pterygoids
               Closure Interference
Premature Contact Causing Forward Displacement of the Mandible




                                          “MUDL” Observation:
                                         Mesial inclines of Uppers
                                       prematurely contacting Distal
                                           inclines of Lowers
Muscles Involved with Forward Displacement of the Mandible




Lateral Pterygoids and Posterior/Middle Temporalis
Closure Interference – Tooth/Jaw Positions
     Deviation to the Opposite Side of the Interference
  Maxillary Facial Cusp to Mandibular Facial Cusp Contact
                    Premature “A” Contact




    Summation: “A” contact will display
  mandibular deviation to the opposite side
Closure Interference – Tooth/Jaw Positions
      Deviation to the Opposite Side of the Interference
 Maxillary Lingual Cusp to Mandibular Lingual Cusp Contact
                    Premature “C” Contact




    Summation: “C” contact will display
  mandibular deviation to the opposite side
  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.
   Lateral Displacement of the Mandible
Condylar Positions on Opposite vs. Same side




 Summation: “A” & “C” contacts will display the condyle on the opposite
     side deviating laterally. The condyle on the same side of the
              interference is anterior to the CR position.
Closure Interference – Tooth/Jaw Positions
     Deviation to the Opposite Side of the Interference
    Maxillary Lingual to Mandibular Facial Cusp Contact
                   Premature “B” Contact




  Summation: “B” contact will display mandibular
   deviation to the same side as 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.
     Lateral Displacement of the Mandible
                           Condylar Positions
       Maxillary Lingual to Mandibular Facial Cusp Contact
                     Premature “B” Contact




  Summation: “B” contacts will display the condyle on the same side
deviating laterally. The condyle on the opposite side of the interference
                      is anterior to the CR position.
Occlusal Interferences & Muscle Responses




                The End

				
DOCUMENT INFO
Shared By:
Categories:
Tags:
Stats:
views:53
posted:3/12/2012
language:Latin
pages:31