Occlusion in Complete Denture

Lec . 6,7 ‫ غسق هشام‬.‫ د‬.‫م‬.‫ا‬

OCCLUSION : the static relationship between the incising and masticating surfaces
of the maxillary or mandibular teeth or tooth analogues.

ARTICULATION : It is contact relationship of maxillary and mandibular teeth as

they move against each other.

centric relation CR; a maxilla mandibular relationship, independent of tooth

contact, in which the condyles articulate in the anterior-superior position against the
posterior slopes of the articular eminences .it is a clinically useful, repeatable
reference position.(bone to bone)
centric occlusion : the occlusion of opposing teeth when the mandible is in centric
relation; this may or may not coincide with the maximal intercuspal position. (tooth
to tooth)

occlusal balance : a condition in which there are simultaneous contacts of opposing

teeth or tooth analogues on both sides of the opposing dental arches during eccentric
movements within the functional range
occlusal harmony : a condition in maximal intercuspal position and eccentric jaw
relation in which there are no interceptive or deflective contacts of occluding
surfaces
occlusal interference
1. Any tooth contact that inhibits the remaining occluding surfaces from achieving
stable and harmonious contacts;
2. Any undesirable occlusal contact

Maximal intercuspal position the complete intercuspation of the opposing

teeth,independent to condylar position

✓ Mandibular movement can be: opening closing, protrusive, and lateral in

lateral it may be
Working side is the side that the mandible move toward it in lateral excursion.
Nonworking side is the side that the mandible move away from during lateral
excursion.
Requirements of ideal complete denture occlusion:
1. Stability of denture in both centric and eccentric relation.
2. Balanced occlusal contact bilateral.
3. Cusp height reduced to control horizontal force.
4. Cutting, penetrating and shearing efficiency of occlusal surface.
5. Incisal clearance during posterior function like chewing.
6. Unlocking (removing interference) of cusps mesiodistally.

Objectives of occlusion in complete denture

‫اﻟﺪﻧﺠﺮ ﻳﻌﻮض اﻟﺠﻤﺎﻟﻴﻪ واﻟﻮﺿﻴﻔﻪ واﻟﻤﻈﻬﺮ واﻻﺻﻮات‬
Preservation of the remaining tissues ‫ﺣﺘﻰ اﺣﻘﻖ وﺿﺎﺋﻒ‬
ً
‫وأﻳﻀﺎ اﺣﺎﻓﻆ ﻋﻠﻰ ﺛﺒﺎﺗﻴﺔ اﻟﺪﻧﺠﺮ‬
Proper masticatory efficiency
Enhancement of denture stability, retention and support
Enhancement of phonetics and esthetics
TYPES OF OCCLUSION
o Balance occlusion
o Lingualized occlusion
o Monoplane occlusion

Balance occlusion
Balance occlusion in complete dentures can be defined as stable simultaneous
contact of the opposing upper and lower teeth in centric relation position and a
continuous smooth bilateral gliding from this position to any eccentric position
within the normal range of mandibular function.

In lateral excursion: (working side)

Anterior teeth- the maxillary & mandibular anterior teeth contact on the working
side.
Posterior teeth- the buccal & lingual cusps of the maxillary & mandibular
posterior teeth are in contact. If lingualized occlusion, the maxillary lingual cusp will
be in contact with the mandibular lingual cusp.

In lateral excursion: balancing side

Anterior teeth- the maxillary & mandibular anterior teeth may contact on the
balancing side.
Posterior teeth- the lingual cusps of the maxillary teeth will be in contact with
the buccal cusps of the mandibular teeth. With monoplane balanced occlusion,
usually only the second molars are in contact or the balancing ramp. ‫ﻣﻨﺤﺪر اﻟﺘﻮازن‬

Advantages of Balance occlusion

1. Distribution of load
2. Stability
3. Reduced trauma
4. Functional movement
5. Efficiency
6. Comfort
Factors affecting the balanced occlusion (Laws of Articulation Hanau quint)
1. Condylar guidance
2. Incisal guidance
3. The occlusal plane
4. The compensatory curves
5. Cusp angulation

• Inter relation between these factors may be described by Theilman̕ s formula.

condylar inclination X Incisal guidance s
• Balanced occlusion = -----------------------------------------------------------
Occlusal plane X compensatory curve X cusps angulation

1.Condylar guidance
The angle formed by an imaginary horizontal line at the superior head of the condyle
and the path that the condyle will pass through during function. It varies from
individual to individual because of anatomical differences. About 33⁰
Definitions
1.condylar guidance: mandibular guidance generated by the condyle and articular
disc traversing the contour of the articular eminence GPT9
2.condylar guidance : the mechanical form located in the posterior region of an
articulator that controls movement of its mobile memberGPT9
The first factor of occlusion is the condylar guidance, this factor recorded from the
patient .so it is fixed factor cannot be modified by the dentist.
2. Incisal guidance:
1. Incisal guidance: - the influence of the contacting surfaces of the mandibular and
maxillary anterior teeth on mandibular movements.
It is usually expressed in degrees of angulation from the horizontal by a line drawn
in the sagittal plane between the incisal edges of the upper and lower incisor teeth
when closed in centric occlusion.
2. Incisal guidance:-the influences of the contacting surfaces of the guide pin and
guide table on articulator movements.

Incisal guidance depends on the:

1.Desired over jet.
‫اﻟﻌﻼﻗﻪ ﻃﺮدﻳﻪ ﻣﻊ اﻻوﻓﺮ ﺑﺎﻳﺖ وﻋﻜﺴﻴﻪ ﻣﻊ اﻻوﻓﺮ ﺟﺖ‬
2.Over bite.
• This angle varies directly with the vertical overbite and inversely with the
horizontal over jet.
• This angle is set to 10˚ in CD and not exceeding 20˚
• This angle determined by esthetic, phonetic, ridge relation, inter-alveolar
distance, this means it is under the control of the dentist,
‫ﻣﻤﻜﻦ اﺗﺤﻜﻢ ﺑﻴﻬﺔ وﺗﺘﻐﻴﺮ ﻋﻜﺲ اﻟﻜﻮﻧﺪاﻳﻠﺮ ﻛﺎﻳﺪﻧﺲ ﻛﺎﻧﺖ ﺛﺎﺑﺘﻪ وﻣﻨﻜﺪر ﻧﻌﺪل ﻋﻠﻴﻬﺔ‬

3.plane of occlusion:
1. lt is imaginary surface related anatomically to the cranium and theoretically
touches the incisal edge of incisors and the tip of occluding surface of posterior teeth
2. Maxillary occlusal plane should parallel to interpapillary line ,posteriorly usually
parallel to the ala-tragus line
3. In the mandible established anteriorly by the cusp height of lower canine near the
commissure of the mouth(corner) and posteriorly by the retromolar pad.
4.The compensating curve:
the arc introduced in the construction of complete removable dental prostheses to
compensate for the opening influences
produced by the condylar and incisal guidance’s during lateral and protrusive
mandibular eccentric movements GPT9
- The compensating curve incorporated in a properly oriented plane of occlusion
- Compensating curve in artificial dentition is anteroposterior curve

5.Cuspal angulations or inclination of cuspless artificial teeth

It depends on several factors residual ridge,neuromuscular control,
esthetics,etc)however, it’s better to reduce the cuspal inclination to help reduce
horizontal forces of occlusion.
Interaction of the five factor
Of the four that he can control two of them (the incisal guidance and the
plane of occlusion) can be altered only a slight amount because of esthetic
and physiologic factors. The important working factors for the dentist to
manipulate are the compensating curve and the inclinations or cusp on the
occlusal surfaces of the teeth.

2- Lingualized occlusion:
It involves use of large upper palatal cusp against wide shallow lower central fossa.
•The buccal cusps of upper and lower teeth do not contact each other.
•The maxillary palatal cusp tip should contact opposite mandibular central fossa.
•The cusp incline of mandibular teeth relatively flat result in less lateral force and
displacement during function

Indication:
1.High esthetic needed.
2.Week muscle of mastication.
3.Displaceable supporting tissue.
4.Sever alveolar bone resorption.
5.Discrepancy in jaws size. Narrow upper arch and wide lower arch
6.implant supported over denture.
7.Previous successful denture with lingualized occlusion.
Advantages:
1. Simpler technique. Less precise CR records
2. Esthetics.
3. Better penetration of the food bolus.
4. easer to adjust occlusion
5. it may be used in clII,classIII and cross bite.
6. Centralization of vertical forces.
7. Minimizing tipping force.
8. Potentially of bilateral balance

Disadvantages:-
1.Difficulty in obtaining repeatable centric record (incoordination, jaw malrelation)
2.Severe ridge resorption (lateral forces displace the denture) may more easily be
handled with a monoplane scheme

3- Monoplane or occlusion (neutrocentric) :

o Flat occlusal plane set with non anatomic teeth.
o The antero-posterior occlusal plan parallel to the denture foundation area.
o There is no vertical overlap of anterior teeth.
o Tooth Contact should occur only when mandible in centric relation. .
o Opposing artificial teeth should not contact when jaws in eccentric relation.
o In protrusion there is disclosure of posterior teeth as a result of arrangement
in single plane.the patient is instructed not to incise the bolus
o There is no curve of spee or curve of Wilson (compensating curves).

Indications
1.Jaw size discrepancies CI II, Cl lll ,malocclusion and cross bite
2.Uncoordinated jaw movement.
3.Mostly for geriatric patients.
4.minimal ridge ,resorbed ridge ,it reduces horizontal forces—implant may help.
Advantages:
1.Simple technique and less time consuming.
2.Less precise jaw relation records.
3.Lateral forces are reduced by eliminating Cuspal inclines.
4.Simpler and easier occlusal adjustments.
5.Occlusion is not locked.

Disadvantages:
1.Least esthetic.
2.Poor bolus penetration.
3.Cannot be balanced in eccentric excursions

Types of Occlusal Scheme:

1.Anatomic teeth. '

Simulate the natural teeth form with inclination approximately 33 degree
Advantages:
1.Esthetic.
2.Better food penetration.
3.Vertical stress decrease.
4.Harmony with TMJ and muscle of mastication.
5.Balance occlusion in eccentric position

Disadvantages: _
1.Precise technique requires.
2.More time.
3.Difficult teeth position in CL II &CL III
4.Greater lateral force
2.Semi anatomic teeth
Cusp incline less steep than anatomical teeth called modified anatomical teeth
(less than33⁰)

Advantages:
1.Esthetic.
2.Good chewing efficacy.
3.Less lateral force.
4.Balance occlusion.

Disadvantages
1.least esthetic.
2.poor bolus penetration.
3.cannot be balanced in eccentric excursions

3.Non anatomical teeth:-Flat and without cusp height.

Advantages
1.Used for patient with poor neuromuscular coordination.
2.Used for patient with malrelation jaws.
3.Used for patient with cross bite or class lll.
4.More comfortable.
5.Less time required in set up.
6. slightly more esthetic than neutrocentric occlusion.

Disadvantages: _
•Use of compensatory curve may cause the same damaging effects as cuspal inclines.
•Occlusal adjustment are more difficult to accomplish

Balance Occlusion For Non Anatomic Teeth May Be

Accomplish By

Factors influencing the selection of selection of occlusal scheme

1. Characteristics of occlusal scheme:
• Tooth form and arrangement
• Balanced or not
2. Characteristics of the patient:
• Height and width of the residual ridge
• Aesthetic demands of the patient
• Skeletal relations
• Neuromuscular control
• Tendency for parafunctional activity