occlusal correction

1. OCCLUSAL
EQUILIBRATION
PRESENTED BY:
DR. KELLY NORTON
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2. INTRODUCTION
HOW TO RECOGNIZE A STABLE OCCLUSION REGARDLESS OF WHAT IT LOOKS LIKE
• 1. Stable stops on all teeth when the condyles are in centric
relation
• 2. Anterior guidance in harmony with the border movement
of the envelope of function
• 3. Disclusion of all posterior teeth in protrusive movements
• 4. Disclusion of all posterior teeth on the nonworking
(balancing) side
• 5. Noninterference of all posterior teeth on the working side,
with either the lateral anterior guidance, or the border
movements of the condyle.
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Key point
You must determine stability of holding contacts on each
tooth before analyzing the other four requirements.
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3. HOW TO RECOGNIZE AN UNSTABLE OCCLUSION
REGARDLESS OF WHAT IT LOOKS LIKE
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THREE SIGNS OF INSTABILITY
1. Hypermobility of one or more teeth
2. Excessive wear
3. Migration of one or more teeth
a. Horizontal shifting
b. Intrusion
c. Supraeruption
If any one of the five requirements for occlusal stability is not fulfilled, the occlusion will be unstable

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• OCCLUSAL EQUILIBRATION: The modification of the occlusal form of the
teeth with the intent of equalizing occlusal stress, producing
simultaneous occlusal contacts or harmonizing cuspal relations. ( GPT 9)
• SELECTIVE GRINDING is defined as any change in the occlusion intended
to alter the occlusal surfaces of the teeth or restorations to change their
form. ( GPT- 9)
PRINCIPLES
1. Don’t equilibrate if the outcome is in doubt.
2. A successful outcome can be determined in advance.

5. INDICATIONS
• (1) Assist in managing certain temporomandibular disorders (TMDS) when
• (1) the occlusal appliance has eliminated the TMD symptoms and
• (2) attempts to identify the feature of the appliance that affects the symptoms
have revealed that it is the occlusal contact or jaw position
• (2) Complement treatment associated with major occlusal changes
• If extensive crown and fixed prosthodontic procedures are necessary, selective
grinding may be indicated before treatment begins so that a stable functional
mandibular position is established to which the restorations can be fabricated
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6. TREATMENT GOALS OF SELECTIVE GRINDING
• 1. With the condyles in the musculoskeletally stable (CR) position and the
articular discs properly interposed, all possible posterior teeth contact evenly
and simultaneously between centric cusp tips and opposing flat surfaces.
• 2. When the mandible is moved laterally, laterotrusive contacts on the anterior
teeth disocclude the posterior teeth.
• 3. When the mandible is protruded, contacts on the anterior teeth disocclude
the posterior teeth.
• 4. In the upright head position (alert feeding position) the posterior teeth contact
more heavily than the anterior teeth.
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7. Predicting the Outcome of Selective Grinding
• “RULE OF THIRDS”
• It deals with the buccolingual arch discrepancy when the condyles are in the
musculoskeletally stable position.
With the condyles in centric relation, the mandible is closed to
tooth contact.
If the initial contact of the lower centric cusp is on the third
closest to the central fossa of the opposing tooth ,
selective grinding can be successfully accomplished.
The nearer the location of this contact to the middle third,
the more likely it is that selective grinding will lead to the
exposure of dentin and the need for restorative procedures.
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8. • Anteroposterior discrepancy:
Visualize the centric relation–
to–intercuspal position (CR-
to-ICP) slide.
• The shorter the slide, the
more likely it is that selective
grinding can be accomplished
within the confines of the
enamel.
• Generally an anterior slide of
less than 2 mm can be
successfully eliminated by a
selective grinding procedure.
Anteroposterior direction of the slide.
A, when the cusps are relatively tall (sharp), the direction
of the CR-to-ICP slide is predominantly vertical.
B, when the cusps are relatively flat, the CR-to-ICP slide
has a greater horizontal component.
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9. ARMAMENTARIUM FOR OCCLUSAL
EQUILIBRATION
• Small diamond wheel stone and a 12-sided football-shaped finishing bur
work well for precise reduction and reshaping.
• Red and black marking ribbons are held in Miller ribbon holders.
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10. • EQUILIBRATION PROCEDURES CAN BE DIVIDED INTO FOUR PARTS:
• 1. Reduction of all contacting tooth surfaces that interfere with the completely
seated condylar position (centric relation)
• 2. Selective reduction of tooth structure that interferes with lateral excursions.
This will vary as the influence of the anterior guidance varies to accommodate to
individual chewing cycles. It will also vary, as necessary, to minimize lateral
stresses on weak teeth.
• 3. Elimination of all posterior tooth structure that interferes with protrusive
excursions. This must be varied in arch-to-arch relationships in which the
anterior teeth are not in a position to disclude the posterior teeth in protrusion.
• 4. Harmonization of the anterior guidance. It is most often necessary to do this
in conjunction with the correction of lateral and protrusive interferences
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11. GRINDING RULES
• Rule 1: Narrow stamp cusps before reshaping fossae
• Rule 2: Don’t shorten a stamp cusp
• Rule 3: Adjust centric interferences first
• Rule 4: Eliminate all posterior incline contacts. Preserve cusp tips only.
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12. Eliminating Interferences to Centric Relation
• 1. Interference to the arc of closure
• 2. Interference to the line of closure
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13. Interference to the arc of closure
• As the condyles rotate on their centric
relation axis, each lower tooth follows an
arc of closure.
• Any interference with this closing arc -
displacing the condyles down and forward
to achieve maximal intercuspation at the
most closed occlusal position.
• Primary interferences that deviate the
condyle forward produce what is
commonly called an anterior slide.
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14. Anterosuperior And Right Slide
The inclines on the right side that cause a right shift
of the mandible are the inner inclines of the
maxillary lingual cusps against the inner inclines of
the mandibular buccal cusps
(mediotrusive CR interferences)
The inclines located on the left side that cause a right
shift of the mandible are either
the inner inclines of the maxillary buccal cusps against
the outer inclines of the mandibular buccal cusps or
the outer inclines of the maxillary lingual cusps against
the inner inclines of the mandibular lingual cusps
(laterotrusive CR interferences
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Anterosuperior And Left Slide
These areas are similar to those causing the
right shift but on the opposite side of the dental
arches.
A, Mediotrusive centric relation interferences on
the left side shift the mandible to the left.
B, Laterotrusive centric relation interferences on
the right side shift the mandible to the left.

16. The basic grinding rule to correct an anterior slide is always
MUDL: Grind the Mesial inclines of Upper teeth or the Distal inclines of Lower teeth
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17. Interference to the line of closure
• Line of closure interferences refer to primary interferences that cause the mandible to
deviate to the left or the right from the first point of contact in centric relation to the most
closed position
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• If the interfering incline causes the mandible to
deviate off the line of closure toward the tongue,
the grinding rule is: Grind the lingual incline of
the upper or the buccal incline of the lower, or
both inclines.
• If the interfering incline causes the mandible to
deviate off the line of closure toward the cheek,
grind the buccal incline of the upper or the
lingual incline of the lower, or both inclines.

18. ACHIEVING THE CENTRIC CONTACT POSITION
• When a contact is
found on an incline
close to a centric cusp
tip, it is eliminated.
• When a contact area is
located on an incline
near the central fossa
area, the incline is
reshaped into a flat
surface.
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One or both of the contacts will be on an incline, either the mesial and distal inclines or
the buccal and lingual inclines.
To eliminate the CR slide, these inclines must be reshaped into cusp tips or flat
surfaces.

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An acceptable CR position has been developed when:
• Equal and simultaneous contacts occur
between cusp tips and flat surfaces on all
posterior teeth.
• When the mandible is guided to CR and
force is applied, no shift or slide occurs.
(There are no inclines to create a slide.)
• When the patient closes and taps in
centric, all the posterior teeth are felt
evenly.
• When this is accomplished, orthopedic
stability has been achieved.

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• 1. Acceptable laterotrusive contacts occur
between the buccal cusps and not the lingual
cusps.
• 2. During a straight protrusive movement, the
mandibular incisors pass down the lingual
surfaces of the maxillary incisors, disoccluding
the posterior teeth.
• During any lateroprotrusive movement, the
lateral incisors can also be involved in the
guidance.
• As the movement becomes more lateral, the
canines begin to contribute to the guidance.
The grinding
rule is simple:
Grind all red
marks on
posterior
teeth.
Do not touch
any black
marks.
DEVELOPING AN ACCEPTABLE LATERAL AND PROTRUSIVE GUIDANCE

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Ask the patient to close in CR
and visualize the relationship
of the anterior teeth.
Then assist the patient through
the laterotrusive movements
It is recommended to clear
balancing interferences first,
then working interferences,
and finally protrusive
interferences
ADJUSTING FOR LATERAL INTEREFERNCES

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Balancing-side or non-working side interferences
on second molars are among the most commonly
missed interferences.
ADJUSTING FOR LATERAL INTEREFERNCES

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• On the working side, the canines should contact during laterotrusive
movements and disocclude all the posterior teeth (canine guidance).
• When the canines are not positioned such that they can immediately provide
laterotrusive guidance, a group function guidance - the mandible is laterally
guided by the premolars and mesiobuccal cusps of the first molars.
A, During a left lateral
movement, the canine contacts
provide canine guidance.
B, Once the mandibular canine
passes beyond the maxillary
canine, the anterior teeth
should contact. This is called
the crossover.
ADJUSTING FOR LATERAL INTEREFERNCES

24. When a cusp tip does not contact an opposing tooth surface
during eccentric movements, the opposing flat surface is
reduced
When a cusp tip does contact an opposing tooth surface, the
cusp tip is reduced
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ADJUSTING FOR LATERAL INTEREFERNCES

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ADJUSTING FOR PROTRUSIVE INTEREFERNCES

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PROCEDURE FOR CANINE GUIDANCE
All blue marks on the posterior teeth are eliminated
without alteration of the established CR contacts (red).

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PROCEDURE FOR GROUP FUNCTION GUIDANCE
• The desirable contacts are the laterotrusive on the buccal cusps of the premolars and
the mesiobuccal cusp of the first molar.

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EVALUATION IN THE UPRIGHT HEAD-POSITION
(Alert Feeding Position)
• To determine whether a postural change in the
mandibular position has occurred that will
cause anterior tooth contacts to be heavier
than posterior tooth contacts
• If the posterior teeth are contacting
predominantly, minimal postural change has
occurred and the selective grinding procedure
is complete.
• If, however, the anterior teeth are contacting
heavily or both anterior and posterior teeth are
contacting evenly, a final adjustment in the
alert feeding position is necessary.

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Influence of Functional Head Postures on the Dynamic
Functional Occlusal Parameters
• Aim: To evaluate the influence of head postures on the dynamic occlusal
parameters.
• The head posture evaluated were supine position, upright sitting position and
alert feeding position. The head postures were standardized by goniometer and
dynamic occlusal contacts were analyzed with Tscan.
• Conclusion: Occlusion time was longest in supine head position while alert
feeding position had the least occlusion time.
Haralur SB, Al-Gadhaan SM, Al-Qahtani AS, Mossa A, Al-Shehri WA, Addas MK. Influence of functional head postures on the
dynamic functional occlusal parameters. Annals of medical and health sciences research. 2014;4(4):562-6.

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VERIFICATION OF COMPLETION
Clench Test Anterior Deprogramming Splint

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COMPUTER-ASSISTED DYNAMIC OCCLUSAL
ANALYSIS
T-scanR II system from Tekscan
(Boston, MA) uses a sensor unit
that records occlusal contacts
on a thin Mylar film and relays
the information to a computer.
Through analysis of the occlusal
contacts, it is possible to
determine the sequence and
timing of which teeth contact
and with what degree of
comparative force

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Balos MD, Soaita C, Cerghizan D, Popsor S. A study on the mandibular arc of closure reproducibility using the T-Scan III
computerized occlusal analysis system. Procedia Technology. 2015 Jan 1;19:916-20.
A Study on the Mandibular Arc of Closure Reproducibility Using the T-Scan III
Computerized Occlusal Analysis System
Aim: To assess the reproducibility of the mandibular arc of closure in various types of
articulators using the T-Scan III system.

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Results:
• The first occlusal contact in mouth is
close to those observed in the non-
arcon articulator.
• Both arcon and non-arcon articulators
are useful devices to diminish the
need for occlusal adjustments in
prosthodontics

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SUMMARY
1. Find and verify centric relation or adapted centric
posture (ACP). Rule out intracapsular disorders.
2. Mount casts with a facebow and a centric
relation or adapted centric bite record.
3. Analyze casts to make sure that equilibration is
the best choice of treatment.
4. Eliminate all deflective inclines that interfere
with complete closure in centric relation or ACP.
5. Verify simultaneous contact on both posterior
teeth and anterior teeth if arch alignment permits.
6. Verify that maximum intercuspation occurs in
perfect harmony with centric relation or ACP.

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SUMMARY
7. Eliminate all excursive contact on posterior teeth.
The only posterior tooth contact is in centric
relation or ACP.
8. Refine anterior guidance for all excursions (may
need to do more reduction of excursive inclines on
posteriors as anterior guidance is altered).
9. Recheck posterior teeth while firmly clenching
and grinding. There should be no contacts on
inclines.
10. Verify dots in back . . . lines in front.
11. Test the results. If an empty mouth clench can
cause any sign of discomfort or pressure in any
posterior tooth, the equilibration is not completed
Dots in back
lines in front.

36. REFERENCES AND CROSS
REFERENCES
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 Management of TMDs and Occlusion. Jeffrey Okeson 6th edt.
 Functional occlusion from TMJ to smile design. Dawson- 3rd ed.
• Balos MD, Soaita C, Cerghizan D, Popsor S. A study on the mandibular arc of
closure reproducibility using the T-Scan III computerized occlusal analysis
system. Procedia Technology. 2015 Jan 1;19:916-20.
• Haralur SB, Al-Gadhaan SM, Al-Qahtani AS, Mossa A, Al-Shehri WA, Addas MK.
Influence of functional head postures on the dynamic functional occlusal
parameters. Annals of medical and health sciences research. 2014;4(4):562-6.