2. TERMINOLOGY
Occlusion:
The static relationship between the incising and
masticatory surfaces of the maxillary or mandibular teeth or
tooth analogues (GPT-8)
Centric occlusion:
The occlusion of opposing teeth when the mandible is in
centric relation. This may or may not coincide with maximum
intercuspation. (GPT-8)
3. Maximum
intercuspation:
The complete
intercuspation of the
opposing teeth,
independent of
condylar position
(GPT-8)
Centric 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 position
against the shapes of the
articular eminencies.
4. Factors governing the position
of teeth for complete dentures
I. The horizontal relations to the residual ridges,
II. The vertical positions of the occlusal surfaces and incisal edges
between the residual ridges,
III. The aesthetic requirements, and
IV. The inclinations for occlusion.
5. Arranging the artificial teeth
The anterior teeth are arranged in basic positions,
principally for esthetics. The posterior teeth are arranged
in maximum planned intercuspation.
For developing the anterior plane of occlusion, the plane
should be located either at or slightly below the corners of
the mouth.
The position of the incisal edges of the mandibular
anterior teeth eventually establishes the level of the
anterior plane of occlusion.
The posterior plane of occlusion is an extension of this
anterior plane level with the junction between the middle
and upper third of the retromolar pads bilaterally.
Junction of anterior 2/3rd and
posterior 1/3rd of Retromolar pad
6. Anterior 2/3rd
Maxillary posterior teeth are arranged in their correct Buccolingual
position:a straightedge is placed over the crest of the mandibular
ridge and a line is scratched in the wax , the lingual cusps of the
maxillary teeth are placed over this line.
The mandibular teeth then assume their buccolingual and
mesiodistal position by intercuspating with maxillary teeth.
The basic principle for the buccolingual positioning of posterior
teeth is that they should be positioned over the residual ridge.
The tip of the canine to the middle of the retromolar pad should
provide guides for this arrangement.
7. Types of posterior
teeth
The standard
anatomic tooth
has inclines of
approximately
33 0 or more.
The cusp incline is less
steep than the
conventional anatomic
tooth of 33 0 . It will
articulate in three
dimensions.
Flat and has sulci to
enhance mastication. They
articulate in only two
dimensions.
9. Anatomical teeth usually are selected for balanced occlusion
Nonanatomical or cuspless teeth are generally the choice for
monoplane occlusion(neutrocentric concept).
Indications of the monoplane occlusion
For the lingualized occlusal concept, a combination of upper
anatomical and lower nonanatomical teeth has been introduced.
Flat ridge(s)
Class II jaw relations
Class III jaw relations
Maxillofacial patients
Handicapped patients
Cross bite
Doubtful / Imperfect centric relation records
11. Requirements of Incising units
These units:
Should be sharp in order to cut efficiently
Should not contact during mastication
Should have as flat an incisal guidance as possible considering
esthetics and phonetics
Should have horizontal overlap to allow for base settling without
interference
Should contact only during protrusive incising function
12. Requirements of Working occlusal
units
Should be efficient in cutting and grinding
Should have less bucco-lingual width – to minimize the work load
Should function as a group with simultaneous harmonious contacts at
end of the chewing cycle
Should be over the ridge crest in the masticating area for lever
balance
Should have a surface to receive & transmit the force vertically
Should center the work load near the anteroposterior center of the
denture
13. Requirements of Balancing
occlusal units
Should contact on the second molars when the incising units
contact in function
Should contact at end of the chewing cycle when the working
units contact
Should have smooth gliding contacts for lateral and
protrusive excursions
15. Factors that affect occlusal balance
1. Condylar guidance
2. Incisal guidance
3. The plane of occlusion
4. The compensating curve
5. Inclination of Cusps
16. The inclination of the condylar guidance
The sagittal condylar guidance angle (SCGA)
- The angle formed by the inclination of a condylar guide control surface
of an articulator and a specific reference plane
17. Not under the control of the
dentist and is determined purely
by the biomechanics of the joint
itself.
This is the net result of
the condyle-disc assembly
passing forwards and
downwards, under the
influence of the anterior
slope of the glenoid fossa.
18. Inclination of the incisal guidance
The influence of the contacting surfaces of the mandibular and
maxillary anterior teeth on the mandibular movements. (GPT-8)
Or
The influences by the amount of vertical and horizontal overlap of the
maxillary and mandibular teeth. (GPT-8)
The angle formed by the
intersection of the plane of
occlusion and a line within
the sagittal plane
determined by the incisal
edges of the maxillary and
mandibular central incisors
when the teeth are in
maximum intercuspation
(GPT-8)
19. The plane of occlusion
The plane of occlusion is established by the height of the lower
cuspid and in the posterior by the height of the retromolar pad.
It is also related to the ala-tragus line, or camper’s line.
Inclination of Cusps
These modify the effect of the plane of occlusion and the
compensating curve.
It was shown that the mesiodistal cusp heights that interdigitate lock
the occlusion so that reposition of the teeth due to setting of the base
cannot take place. Therefore only buccolingual inclines need be
considered as determinants of balanced occlusion.
20. Compensating curve
The anteroposterior curving (in the medial plane) and the
mediolateral curving (in the frontal plane) within the
alignment of the occluding surfaces and incisal edges of
the artificial teeth that is used to develop the balanced
occlusion(GPT-8)
21. Bilateral balance in lateral excursions is the desired outcome
Working
Balancing
Centric
