Occlusion-N Flashcards
What is a joint/articulation?
What is the connection between two separate parts of the skeleton
TMJ synonyms
Temporomandibular joint
Craniomandibular articulation
What is TMJ?
It is the ARTICULATION between the MANDIBLE and the two bones on the base of the skull called the TEMPORAL bones
Parts of TMJ
There are three parts on each half of the TMJ
1. MANDIBULAR CONDYLE —-the process of the mandible.
- The ARTICULAR or the GLENOID FOSSA.— shallow, concavity on the base of the skull in the temporal bone
3 the ARTICULAR EMINENCE or RIDGE
- The ARTICULAR DISCinterpose between these two bony parts 
These three parts are enclosed by a FIBROUS CONNECTIVE TISSUE CAPSULE
The articular, or the glenoid fossa
It is a non-functional portion of the joint
In the glenoid fossa, how many surfaces touch
Two surfaces touch
- ANTERIOR SURFACE of the condyle and the posterior slope of the articular eminence contact.
2.MEDIAL WALL of the glenoid fossa.
Articular disk
It is made up of FIBROCARTILAGE . It is a SYNOVIAL JOINT
The disc is a tough band of dense, fibrous, connective tissue that acts as a SHOCK ABSORBER between the mandibular condyle and the articular Fossa and the articular Eminence
It stabilizes the condyle by filling the space between the different contours of the condyle, and the articular, fossa and articular eminence
This is a ginglymoarthroidal joint (sling like). How many compartments does it have?
2 compartments:
- Superior(upper)—translation
2 Inferior (lower.)— rotation 12 to 15 mm.
Proprioceptive fibres in the disc
They help to REGULATE MOVEMENT of the condyle by UNCONSCIOUSLY determining the POSITION of MANDIBLE
Posterior determinant of occlusion
Mandibular condyle
Protrusive movement and
lateral movement
Anterior determinant of occlusion
Teeth
Protrusive movement—-anterior teeth
Lateral movement — canine and group function
Mandibular movements
They can be
FUNCTIONAL—mastication,speech ,yawning
PARAFUNCTIONAL — clenching, tapping, grinding
The movement of the mandible is by virtue of two factors
NEUROMUSCULAR CONTROL -it is the movement of the mandible which occurs with the help of muscles under the influence of nervous system
HARD TISSUE GUIDANCE —-TMJ—-posterior guidance
——-occlusal surface of TEETH——anterior guidance
The planes of mandibular movement
Three planes:
- frontal, coronal, or lateral plane
- sagittal , longitudinal plane
3.horizontal, axial, or transverse plane
See diagram pg 5- naresh- new
Hinge Axis
Also called the Horizontal axis or the Axial axis
Definition of hinge axis
It is the TRANSVERSE AXIS that runs horizontally from one side of the condyle to the other side of the condyle, or from one side to the other side of the mandible
Important points, hinge axis
- The axis VARIES during different phases of protrusive movement.
- during INITIAL mouth opening, the axis is present at the head of the condyle.
- During LATE stage of mouth opening the axis passes through the mandibular foramen
- Rotation around its axis is seen during.:Protrusive movement
Mouth opening movement
The rotational mandibular movement
12 to 15 mm
Process of turning around an axis
The rotation occurs when the mouth opens and closes around a fixed point or access within condyle
The teeth can be separated, and then occluded with no positional change of the condyle
Translational movement of mandible
The movement in which every point of moving object simultaneously has the same DIRECTION and VELOCITY
This occurs in MANDIBLE moves FORWARD as in protrusion
The teeth condyle, and rami —-all move in the SAME DIRECTION and SAME DEGREE
Planes
Planes:
- FRONTAL or CORONAL plane or LATERAL plane ——divides the body into front and back
- HORIZONTAL PLANE or AXIAL plane or TRANSVERSE plane.—-divides the body into upper and lower parts
- SAGGITAL PLANE or LONGITUDINAL plane.— divides the body into left and right sections
- MEDIAL PLANE —-equals left and right sides.
5.PARASAGGITAL PLANE
- OBLIQUE PLANE—-anything not parallel to these three
Posselt’s envelop of motion
- Sagittal plane and horizontal axis.— dagger
- Frontal plane and saggital axis.—— shield
- Horizontal plane and vertical axis—- diamond
Sagittal axis
It is an imaginary access that runs along the mid sagittal plane
What is horizontal from front to rear at right angle to the frontal plane

The mandible around the axis shows little rotational movement
During movement, the mandible moves downwards and mediately along the slope of the Enteroglenoid process on the (nonworking side).
The other side of the condyle will move upward and laterally(working side)
Shield diagram
Frontal plane
Suggitalaxis
Vertical axis/longitudinal axis
Axis that run through the condyle, and the posterior border of ramus
Passes from head to foot at the right angle, transverse plane, or horizontal plane
Rotational movement of mandible is sing-along, vertical axis
Diamond shape
Horizontal plane
When mandible moves in lateral excursions, the centre for rotation is a vertical axis, extending through the rotating, or the working side condyle
Frontal plane is also called
Coronal plane or lateral plane
Horizontal plane is also called
Axial plane or transverse plane
Sagittal plane is also called
Longitudinal plane
