41 terms

Occlusion

STUDY
PLAY
Passive Structures of Articulation
1. Osseous anatomy of the joints
2.Limiting influence of the ligaments
3. Shape and orientation of the occlusal plane
Active elements of Articulation
1. Muscles
2. Reflex responses that arise in and around the teeth, joints, muscles, and periodontium
Muscles of the TMJ
1. Positioner muscles (lat. pterygoid & temporalis)
2. Elevator muscles (masseter and med. pterygoid)
3. Depressor muscles (suprahyoids and infrahyoids)
Lateral pterygoid
Function: protrusion, pulls/ holds the disk forward and assists rotary movement of mandible
Superior head of lateral pterygoid
Origin- infratemporal surface of sphenoid greater wing
Insertion- Medial 1/2 of the "foot" of the disk and head of the condyle
Inferior head of lateral pterygoid
From lateral surface of lateral pterygoid plate to the neck of the condyle
Temporalis
Origin- temporal fossa and temporal fascia
Insertion- Coronoid process and anterior border of ramus
Masseter (Superficial)
Origin- Anterior 2/3 of lower border of zygomatic arch
Insertion- Lateral surface of angle of mandible
Masseter (Deep)
Origin- Medial surface of zygomatic arch
Insertion- Lateral surface of ramus and angle of mandible
Suprahyoids
Geniohyoid
Digestric
Myelohyoid
Stylohyoid
Infrahyoid
Thyrohyoid
Sternothyroid
Sternohyoid
Omohyoid
Posterior neck muscles
Sternocleidomastoid
Trapezius
Intrinsic neck muscle
Mouth Opening
Suprahyoids
- geniohyoid
- mylohyoid
- Digastric
- Stylohyoid
Infrahyoid and Posterior Neck Musculature
Closing
Superior head contracts
Inferior head relaxes
Nerve control
Mandibular division of the trigeminal nerve gives motor innervation to the muscles of mastication
Blood supply
Maxillary artery
Facial Artery
External Carotid Artery
Ligaments of TMJ
Medial and lateral collateral ligaments
Posterior ligament
Temporomandibular ligament
Sphenomandibular Ligament
Stylomandibular ligament
Wh
Sphenomandibular ligament
O- Angular spine of sphenoid
I- Mandibular lingula
Stylomandibular ligament
O- Styloid process
I- Angle of the mandible
Proprioception
the exquisitely sensitive protective reflex system that guards the teeth and their supporting structures against excessive stress
Which ligaments maintain the position of the disk in relation to the condyle
The medial and lateral collateral ligaments and the posterior ligament
What ligament facilitates translation of the condyle and prevents rotation that would compromise the anatomic structures in the neck
Temporomandibular ligament
Concentric relation
the maxillomandibular relationship in which the condyles articulate with the thinnest avascular portion of their respective disks with the complex in the anterior-superior postion against the slopes of the articular eminences. This position is independent of tooth contact and it is restricted to a purely rotary movement about the transverse horizontal axis. The medial pols of the condyle are braced against the medial articular lip of the fossa
Centric occlusion
the contact of the teeth when the TMJs are in centric relation
Maximum intercuspation
the relation of the mandible and maxilla when the teeth are in maximum occlusal contact, irrespective of the position or alignment of the condyle disk assemblies
Goal of occlusal treatment
to have MI with the TMJs in centric relation
Any movement from CR is...
downwards
Engrams
muscle memory
A Contacts
"A" contacts are on the mandibular stamp cusps and may be located on the facial surface up to the crest of the marginal ridge against the inner inclines of the maxillary opposing or shearing ridges. There is an "A" contact on the mesial and distal side of each stamp cusp that has an opposing tooth.
B Contacts
"B" contacts are always on inner inclines of stamp cusp ridges (opposing stamp cusp ridges). They may be located just off the tip of the stamp cusp anywhere along the ridge just before the base of the ridge.
C contacts
C" contacts are on maxillary stamp cusps and may be located on the lingual surface up to the crest of the marginal ridge against the inner inclines of the mandibular shearing ridges.
ABC contacts
stabilize the teeth bucco-lingually
Closer stopper contacts
those contacts that occur on the mesial occlusal inclines of mandibular teeth and on distal occlusal inclines of maxillary teeth (Close to the tip)
Equalizer occlusal contacts
contacts that occur on the distal occlusal inclines of mandibular teeth and on the mesial occlusal inclines of maxillary teeth (close to the fossa)
Number of cusp tips (elevations) in the maxilla and mandible
Maxilla= 24
Mandible= 26-30 (depending on the size and shape of the 2nd premolar and 2nd molar)
Stamp cusps
Functional cusps (Maxillary lingual cusps and mandibular buccal cusps)
Shearing cusps
Nonfunctional cusps (Maxillary buccal cusps and mandibular lingual cusps)
Marginal ridges
the highest contours that circumscribes the occlusal table
Cusp- Marginal ridge contact
One tooth to two teeth
Cusp - Fossa contact
One tooth to one tooth
Tripodized Cusp - Fossa Contact
Tangential contacts around the tip of the cusp- none at the tip

May occur in unworn dentition or created for full mouth rehab

Must have contacts on opposing inclines of same cusp or other cusps on the same tooth to prevent slide