occlusion

UNIVERSITY OF MOSUL COLLEGE OF DENTISTRY

2020-2021
Department of Prosthodontics
Department of: HERE
COMPLETE DENTURE OCCLUSION
By: Dr. Monia MN Kandil 5
Concepts of OCCLUSION

UNIVERSITY OF MOSUL COLLEGE OF DENTISTRY

I- Concepts Of Occlusion In Centric Position.
a. Concepts of balanced occlusion.
II- Concepts Of Occlusion In Eccentric Position:-
b. Concepts of non-balanced occlusion.
1- Point centric. 2- Long centric. 3- Slide centric. 4- Power centric.

UNIVERSITY OF MOSUL COLLEGE OF DENTISTRY

1- Point Centric
Anatomic teeth set in tight interdigitated centric occlusion with an incisal overlap for esthetics
I-Concepts of Occlusion in Centric Position:
Point Centric occlusion: Involves positioning of the teeth with a compensating curves (Spee, Wilson & Monson’s curves) running anteroposteriorly and mediolaterally to simulate natural teeth. The point centric concept is that in which centric occlusion coincide with centric relation perfectly, such occlusion in Complete Denture is neither stable nor physiologic. So Function and stability of complete dentures are well served by the freedom in centric concept

UNIVERSITY OF MOSUL COLLEGE OF DENTISTRY

Once CR is established, CO can be built to coincide with it and provide a broad area of tooth contact in this position called “Freedom in Centric " 2- Freedom of Centric (Long Centric)
It is a relatively flat area created between centric relation and centric occlusion. This flat region, having a length of 0.5-1mm, gives the mandible freedom to close in Centric or slightly anterior to it without any interference or without any changes in vertical dimension.
I-Concepts of Occlusion in Centric Position:

UNIVERSITY OF MOSUL COLLEGE OF DENTISTRY

When cuspless teeth are used this freedom exists automatically. In both situations (using anatomic or non-anatomic teeth) the anterior teeth are arranged to allow this freedom of movement i.e. enough over-jet & over-bite.
the occlusal surface of the teeth could be altered to allow freedom of tooth movement in harmony with the rotation of condyle. (from hinge position to habitual intercuspal position).
2- Freedom of Centric (Long Centric)
I-Concepts of Occlusion in Centric Position:

UNIVERSITY OF MOSUL COLLEGE OF DENTISTRY

I-Concepts of Occlusion in Centric Position:
Through caries, wear, loss of teeth or poor dentistry, sliding movement that the mandible makes as it moves from retruded contact position to intercuspal position, but with a new Habitual position i.e. (slide in position), often it’s a combination of forward and lateral movements, as well as vertical components . 3- Slide in Centric (Eccentric Slide)
Q: Does the mandible really “slide” into MI from the Retruded Contact Position during closure (not chewing) ?A: No, it closes along an arched path which leads directly to MI position. Q: What is the name of this path?A: Habitual Arc of Closure.Q: Should there be centric on Anteriors ?A: Anterior teeth are arranged to allow freedom of movement

UNIVERSITY OF MOSUL COLLEGE OF DENTISTRY

I-Concepts of Occlusion in Centric Position:
Posselt’s Figure To understand the Habitual Arc of Closure, we must know about Posselt’s Figure: MO
ICP
MP = Maximal protrusion ICP = Intercuspal position RCP= Retruded Contact position HA = Hinge axis MO = Maximum opening EE=edge to edge
Posselt’s Figure MP
RCP
HA
Habitual Arc of Closure
EE
Habitual Arc of Closure
In that case the intercuspal position is in a position forward to the centric position, and at a lower vertical dimension
MO

UNIVERSITY OF MOSUL COLLEGE OF DENTISTRY

I-Concepts of Occlusion in Centric Position:
4- Power centric
The patient close against force and determining the position of the mandible in which the patient could bite the hardest. This position does not necessarily correspond to any of the three previously mentioned "centrics" since it is based on a different premise.

UNIVERSITY OF MOSUL COLLEGE OF DENTISTRY

I- Concepts Of Occlusion In Centric Position.
a. Concepts of balanced occlusion.
II- Concepts Of Occlusion In Eccentric Position:-
b. Concepts of non-balanced occlusion.
Spherical theory of occlusion.Centralizing concept of occlusion.Lingualized occlusion concept (Gysi).4. Linear occlusion concept.5. Balance with non-anatomic teeth. a. Zero Degree Teeth with Balancing Ramp. b. Tilting the second molars. c. Zero Degree Teeth with a Compensating Curve d. Reverse curve of Wilson. e. Max Pleasure’s modified occlusion.6. Dynamic occlusion (functional generated path).

UNIVERSITY OF MOSUL COLLEGE OF DENTISTRY

A-Concepts of Balanced Occlusion:
1- Spherical Concept of Occlusion:
Positioning artificial anatomic posterior teeth to simulate natural occlusion. The teeth, must be arranged with a compensating curve running anteroposteriorly and mediolaterally.
Anatomic or semi anatomic teeth are arranged in point centric occlusion.
Alignments of cusped posterior teeth determined on the residual ridge that act as a landmark for setting, This is important factor in controlling the force and its effect on stability of the base.
II- Concepts Of Occlusion In Eccentric Position:-

UNIVERSITY OF MOSUL COLLEGE OF DENTISTRY

Teeth make contact in lateral excursion on the working and balancing sides
A-Concepts of Balanced Occlusion:
1- Spherical Concept of Occlusion:
Distribution of masticatory pressure over the supporting tissues help in:
Advantages of arrangement teeth with Spherical concept:
Increased stability of the dentures during functional and parafunctional movements of the mandible. Reduced trauma to the underlying tissues. Increased efficiency of mastication.

UNIVERSITY OF MOSUL COLLEGE OF DENTISTRY

A-Concepts of Balanced Occlusion:
2-The Centralizing Occlusion Concept: (Balanced occlusion by centralization of forces)
The concept of centralizing the working occlusal surfaces requires bringing the occlusal surfaces toward the center of the denture foundation to their ideal positions for favorable leverage
Most favorable leverage is obtained when the occlusal working surfaces are placed to the lingual sides of the ridge crests .The second molars are not always placed in the arrangement; or are placed out of occlusion.
Working occlusal units ideally consist of the lingual halves of the two maxillary bicuspids and the first molar and their corresponding mandibular teeth.
This area located in the area represented upper mesial-second premolar to the upper mesiobuccal cusp-first molar. This zone is the most important for the stability of the denture and mastication

UNIVERSITY OF MOSUL COLLEGE OF DENTISTRY

A-Concepts of Balanced Occlusion:
3- The Lingualized Occlusion:
A method to achieve bilateral balanced occlusion with an attempt to maintain the esthetic and food penetration advantages of the anatomic form while maintaining the mechanical freedom of the non-anatomic form
Lingual bone resorption prevents placing teeth within the neutral zone So Lingualized occlusion helps centralization of force.


UNIVERSITY OF MOSUL COLLEGE OF DENTISTRY
3- The Lingualized Occlusion:
Advantages of lingualized occlusion:
1. Esthetics is maintained. 2. Efficiency is maintained. 3. Mechanical freedom of occlusion from the non-anatomic teeth form. 4. Mechanical stability due to centralized forces. 5. Bilateral balanced occlusion is readily obtained for a region around centric relation. 6. No lateral forces due to one contact point. 7. Lingualized occlusion can be used with all morphologic ridge contours. 8. Buccal cusp tilt allows escape way for the bolus of food.


The maxillary buccal cusps are not in contact, leaving only the maxillary lingual cusps as the centric holding cusps, Vertical forces are centralized on the mandibular teeth. thus directing the forces to the lingual side of the lower ridge crest to encourage lever stability of the denture, and minimizes the points of tooth contacts.
UNIVERSITY OF MOSUL COLLEGE OF DENTISTRY
3- The Lingualized Occlusion:

UNIVERSITY OF MOSUL COLLEGE OF DENTISTRY

3- The Lingualized Occlusion:
In Protrusive movement is possible while maintaining balanced occlusion with minimal overbite of anterior teeth and enough overjet. Selective grinding of mandibular tooth forms is needed to create a slight concavity in the occlusal surface, lefting a shallow cusp form, some time with 0 degree.
In lateral excursive movements clearance between the maxillary and mandibular buccal cusps to increase lever stability to the lower denture.
In Bilateral eccentric equilibration:

UNIVERSITY OF MOSUL COLLEGE OF DENTISTRY

The decision as to whether to locate the linear ridge of contacts in the maxillary or mandibular arch depends on the factors of denture stability and esthetics (weaker arch).
A-Concepts of Balanced Occlusion:
4- Linear Occlusion Concept :
The idea is to minimize the force penetrating food by sharp linear contact between the upper and lower posterior teeth. A line of occlusal contact in one dental arch occluding with a flat occlusal table in the other dental arch.


UNIVERSITY OF MOSUL COLLEGE OF DENTISTRY
5- Balance with non-anatomic teeth:
Placing "balancing ramps" behind the lower second molars. Tilting the second molars to create an inclined plane. Arranging Zero Degree teeth with compensating curves.Reverce Curve of Wilson.Max’s Pleasure Modified occlusion. A-Concepts of Balanced Occlusion:
Disadvantages of Non-Anatomic Occlusion
Aesthetics not desirable. Mastication not efficient.Encourages lateral movement  bruxism.Christensen’s Phenomenon developed.

UNIVERSITY OF MOSUL COLLEGE OF DENTISTRY

5- Balance with non-anatomic teeth:
A- Zero Degree Teeth with Balancing Ramp:
Setting up the teeth in a flat plane and utilize a balancing ramp just distal to the second molar.
artificial tooth. an acrylic ramp. non anatomic porcelain teeth. Amalgam or gold balancing ramp.
Types of balancing ramps:
Some: advocated the use of second molar ramp which is adjusted to provide protrusive and lateral balance (three point balanced occlusion).

5- Balance with non-anatomic teeth:

Protrusive Balance Compensation in Monoplane Denture occlusion: Second Molar Slant
B- Tilting the second molars:
UNIVERSITY OF MOSUL COLLEGE OF DENTISTRY
C- Zero Degree Teeth with Compensating Curves:
Zero degree teeth can be set on lateral and anteroposterior curves harmonious with the condylar inclination to attain reasonable balance contacts in lateral and protrusive positions.


5- Balance with non-anatomic teeth:
UNIVERSITY OF MOSUL COLLEGE OF DENTISTRY
D- Reverse curve of Wilson:
e- Max Pleasure’s modified occlusion: A reverse curve is used in the second premolar area (C) for a lever balance, A flat scheme of occlusion is set in the first molar (B), and a spherical scheme set in the second molar area (A) by raising the buccal incline to provide for balancing contact in lateral position. The distal of the second molar can also be elevated to produce balancing for protrusive movement.
skull with a reverse curve of Wilson.

UNIVERSITY OF MOSUL COLLEGE OF DENTISTRY

A-Concepts of Balanced Occlusion:
6- Functional Occlusion: (Dynamic Occlusion)
The ultimate harmonious balanced occlusal form because the patient generates it by himself resulting in an occlusion that is in harmony with T.M.J and neuromuscular system. This occlusion will allow freedom in lateral excursions and maintain maximum bilateral contact in function.
Functionally generated occlusion

UNIVERSITY OF MOSUL COLLEGE OF DENTISTRY

I- Concepts Of Occlusion In Centric Position.
a. Concepts of balanced occlusion.
II- Concepts Of Occlusion In Eccentric Position:-
b. Concepts of non-balanced occlusion.
1- Monoplane Occlusion (non anatomic occlusion). 2- Neutrocentric Concept of Occlusion. 3- Organic Occlusion. 4- Group function Concept.


We forced to such concept because: The character of the supporting foundation and mucosa resiliency makes it almost impossible to harmonize tooth arrangement with mand. movements in the eccentric relations.
B- Concepts of Non-Balanced Occlusion In Eccentric Position:
To minimize the horizontal forces that are un stabilizing and potentially destructive to the supporting tissues.
When the jaws are in Centric Relation and the contact of the teeth produces no discomfort to the supporting tissues or the joints.
UNIVERSITY OF MOSUL COLLEGE OF DENTISTRY
II- Concepts Of Occlusion In Eccentric Position:-

UNIVERSITY OF MOSUL COLLEGE OF DENTISTRY

B- Concepts of Non-Balanced Occlusion :
Advantages of non-balanced Occlusion:
Simple technique. No lateral forces. Freedom of occlusion. Used with compromised ridges. Necessitates minimum adjustments.
Poor esthetics. Poor masticatory efficiency. No balancing contacts. Restricted penetration and incision. Lateral chewing cycle, or stimulate bruxsim para-function activities.
Disadvantages of non-balanced Occlusion:
II- Concepts Of Occlusion In Eccentric Position:-

UNIVERSITY OF MOSUL COLLEGE OF DENTISTRY

B- Concepts of Non-Balanced Occlusion :
1- Monoplane Occlusion: (Non-Anatomic Occlusion)
Posterior horizontal overlap of flat plane teeth
Non- anatomic teeth with flat occlusal surfaces set to a flat occlusal plane

UNIVERSITY OF MOSUL COLLEGE OF DENTISTRY

B- Concepts of Non-Balanced Occlusion :
1- Monoplane Occlusion: (Non-Anatomic Occlusion)
The posterior limit of the lower posterior teeth is the point at which the mandibular ridge begins to curve upward, with elimination of contact between the upper and lower second molars.
The patients should avoid incising with their anterior teeth

UNIVERSITY OF MOSUL COLLEGE OF DENTISTRY

B- Concepts of Non-Balanced Occlusion :
2- Neutrocentric Concept of Occlusion:
Neurocentric  two objectives in denture construction. A- Neutralization of inclines. B- Centralization of occlusal forces acting on the denture foundations.
1- Neutralization of inclines (elimination of inclines): a- Orientation of occlusal plane parallel to a rich. b- compensating curve, and Incisal guidance are flat. c- No cusp angle.
2- Centralization of occlusal forces acting on the denture foundation, to have:
a- Superior stability. b- preservation of ridge bone. c- Good function.

UNIVERSITY OF MOSUL COLLEGE OF DENTISTRY

B- Concepts of Non-Balanced Occlusion :
Position of Posterior teeth in a central position. Proportion of the teeth 40% reduction in the width. Plane of occlusion is parallel with the mean denture foundation area. Form of teeth devoid of projecting cusps. Number of teeth reduction in number.
Five factors are involved, to achieve these 2 objectives:
2- Neutrocentric Concept of Occlusion:

UNIVERSITY OF MOSUL COLLEGE OF DENTISTRY

B- Concepts of Non-Balanced Occlusion :
3- Organic Occlusion:
Concept that employs cusp form posterior teeth that are not arranged in protrusive or lateral balance.
Organic concept of occlusion can not be accepted, in constructing complete dentures
Eg. For organic occlusion Canine Guidance occlusion: Not applied for denture construction But can used with implant supported fixed prosthesis

UNIVERSITY OF MOSUL COLLEGE OF DENTISTRY

B- Concepts of Non-Balanced Occlusion :
4-The group function concept:
In which two or more of the teeth other than the canines, in contact on the working side and no balancing contacts for either the right or left lateral functional excursions (natural occlusion).
Not applied for denture construction.

THE END

UNIVERSITY OF MOSUL COLLEGE OF DENTISTRY
2020-2021