occlusion

By:
UNIVERSITY OF MOSUL COLLEGE OF DENTISTRY
2020-2021
Department of Prosthodontics
Department of: HERE
Dr. Monia M.N. Kandil
Stomagnathic System Terminology & Definitions
1

UNIVERSITY OF MOSUL COLLEGE OF DENTISTRY

Department of: HERE
The stomatognathic (masticatory) system
Includes: Teeth Periodontium Jaws TMJ Associated muscles + tongue & muscles of the soft palate Investing tissues Neural control
There is a complex, dynamic balance between the way that the teeth come together, the muscle that work the jaws and the joints.

UNIVERSITY OF MOSUL COLLEGE OF DENTISTRY

Department of: HERE
The letters TMJ are short for of 'temporo-mandibular joint', which is a bilateral joint, permits the mandible to move as a unit with two functional patterns: - Hinge - Translation
The movement in this joint lets you open and close your mouth and chew from side to side.
It has 4 anatomical parts: 1- condyle 2- Articular fossa 3- Articular disc 4- Articular capsule

UNIVERSITY OF MOSUL COLLEGE OF DENTISTRY

Department of: HERE
Centric relation
It is the most retruded unstrained position of the condyle in the glenoid fossa from which lateral movements can be performed at any given degree of jaw separation.
It’s restricted to a purely rotary movement about a transverse horizontal axis. It is bone to bone relationship independent on tooth contacts .

The occlusion of opposing teeth when the mandible is in centric relation

Any occlusion other than centric relation
UNIVERSITY OF MOSUL COLLEGE OF DENTISTRY
CENTRIC OCCLUSION
ECCENTRIC OCCLUSION

UNIVERSITY OF MOSUL COLLEGE OF DENTISTRY

MAXIMUM INTERCUSPATION
The complete intercuspation of the opposing teeth independent of the condylar position.
The dynamic movements of the teeth in relation to each other, called Articulation of the teeth.
ARTICULATION



UNIVERSITY OF MOSUL COLLEGE OF DENTISTRY
VERTICAL DIMENSION OF OCCLUSION
The degree of separation between the maxilla and the mandible when the teeth are in occlusion.
INTER OCCLUSAL DISTANCE (Free way space)
The distance between the occluding surfaces of the maxillary and mandibular teeth when the mandible is in a specified position (CR), it ranges from 2-4 mm.

020-2021

UNIVERSITY OF MOSUL COLLEGE OF DENTISTRY
Envelope of functionMost normal chewing stays within the red area, but the lower teeth have the range of the black line.Lower teeth are ‘guided’ by a slope of the upper lingual surfaces, this is called “Anterior Guidance” of the border movement of the envelope chewing cycle, that is in harmony with bone/craniofacial structures . The Masticatory Cycle occur according to theCompensating curves one of the most important factors in establishing balanced occlusion

UNIVERSITY OF MOSUL COLLEGE OF DENTISTRY

Spee’s curve The anatomic curvature of the occlusal alignment of the lower teeth beginning at the tip of the lower cuspid and following the buccal cusps of the natural bicuspids and molars continuing to the anterior border of the ramus
Compensating curves

UNIVERSITY OF MOSUL COLLEGE OF DENTISTRY

Department of: HERE
The buccal cusps of the lower posterior teeth are slightly higher than the lingual cusps, and a line drawn through the buccal and lingual cusps of the teeth on the other side forms a lateral curve called the curve of Wilson
Curve of Wilson
Compensating curves

UNIVERSITY OF MOSUL COLLEGE OF DENTISTRY

Compensating curves
Monson’s curve It is a curve in which each cusp and incisal edge touches or conforms to a segment of a sphere 20 cm (eight inches) in diameter with its center “the glabella”.

UNIVERSITY OF MOSUL COLLEGE OF DENTISTRY

It takes place in the lower compartment of the T.M.J between the superior surface of the condyle and the inferior surface of the articultar disc
It Is a Simple Hinge Movement occurs during the early opening and late closing movement of the mandible
It is an imaginary line around which the condyles rotate during early opening and late closing.
Again ….

UNIVERSITY OF MOSUL COLLEGE OF DENTISTRY

Department of: HERE
Translation movements
Rotation movements
Translation occurs when the mandible moves into a protrusive or lateral position, or a combination of the two.
Dislocation of the joint

UNIVERSITY OF MOSUL COLLEGE OF DENTISTRY

The angle formed by the steepness of the articulator surface that is related to a horizontal plane is called the sagittal inclination (Condylar inclination)
The inclination of the condylar paths varies in different individuals and from side to side in the same person. It depends upon.
The shape of the glenoid fossa. The variation of the thickness of the articular disc in its different parts. The relation of the condyle to the disc during movement. The extent of mandibular protrusion
Condylar Angle:

THE END

UNIVERSITY OF MOSUL COLLEGE OF DENTISTRY
2020-2021