Dental implant courses by Indian dental academy

DEFINITION
~Occlusion is each static contact between one
or more lower teeth iwht one or more upper
teeth
~Functional occlusion refers to the occlusal
contacts of the maxillary and mandibular teeth
during function, i.e. during speech, mastication
and swallowing
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~Intercuspal position is the occlusal with
the teeth in maximum intercuspation
~Retruded axis position is the position the
condyle adopts during the terminal hinge
movement of openeing or closing
~Retruded contact position is the occlusal
position when the first tooth contact occurs
on the mandibular path of closure with the
condyles in the retruded axis position

~Working side is the side that the mandible
moves towards in a lateral excursion
~Non-working side is the side that the
mandible moves away from during a lateral
excursion

OCCLUSAL CONCEPTS
~Angle
~Raymond Begg
~Andrews
~Other modifications

RONALD H. ROTH
~Stability of the treated case
~Benefit to the patient
~Functioning occlusion after bicuspid ext.

ROLE OF EQUILIBRATION
~Tooth positioning close to centric
~Criteria starts from diagnosis, Rx planning
Rx and retention
~Difficulty in occlusal adjustment
~Equilibration after growth is complete

PHILISOPHY & RATIONALE
~Treatment objectives
- Pleasing facial esthetics evaluated
cephalometrically & by soft tissue
-Molar relationship & tooth alignment-Angle
-Functional occlusion-gnathologic articulator
-Comfort, efficiency and longevity of
dentition, supporting structures and TMJ

~Lower jaw up in the socket-ideal
physiological position
~Closure, no forward or backward movt. But
only teeth should mesh
~Teeth should not interfere
~Harmony of occlusion

The mandible should be able to
close into maximum intercuspation
without deflecting the condyles
from their most ideal relationship
in the fossae.

HARMONY OF OCCLUSION
~Defining Ideal relationship of condyle in
fossae
~Degree of accuracy in recording the full
extent of jaw movement
~Type of centric contacts & type of
Excursive occlusal scheme
~Instrumentation

~Centric relation of mandible & centric
occlusion of teeth-identical
~Alleviation of pain
~Orthodontist & Restorative dentist
Arranging the teeth in harmony with condylar
guidance and adjust occlusal plane in relation
to angle of eminence

CENTRIC RELATION
~An idealized treatment goal
~CR of the mandible is a superior limit
position of the condyles in the fossae with the
mandible centered and its most closed
position

~The fact that someone’s occlusion is not
centrically related is not by itself an indication
for treatment
~There are some patients who are not
comfortable in centric , such patients will not
be comfortable anywhere

~CR contrary to popular opinion is not a
strained position. It is only a strained position
if attempts are made to forcibly retrude the
mandible and make the teeth contact where
they do not intercusp
When the teeth fit together with the mandible
seated properly in centric relation there is no
strain

~Williamson-Superior-anterior fossa position
~Stuart-Rearmost, midmost & uppermost
position of condyles in their respective
fossae with the mandible in the closed
position

~Agrees with Dyer & Dawson-when one is
dealing with a patient who has damage to the
TM ligaments and has excess mobility of the
condyles, it is virtually impossible to push the
mandible distally without causing further
inferior positioning or subluxation of condyles,
unless care is taken to support the gonial
angles and even than it is doubtful that
subluxation could be avoided without prior use
of repositioning splint to obtain a stable centric
relation

RECOGNIZING OCCLUSAL DISHARMONY
~Occlusal wear
~Excessive tooth mobility
~TMJ sounds
~Limitation of opening or movement
~Myofacial pain
~Contracture of mandibular musculature
making manipulation difficult
~Some types of tongue thrust swallow

~Patients do not adapt to occlusal
interferences, they tolerate them, but the
tolerance becomes less as they grow older
~Tolerance level > Symptomatic
~Occlusal disharmonies should be treated
prior to orthodontic treatment

~Occlusal interferences-classify
1.Those with symptomatology
2.Pschycologically or physically predisposed
to developing a problem
3.Those that are neither symptomatic nor
predisposed to developing symptoms

OCCLUSAL INTEREFERENCES
TEND TO MAKE TEETH AND
JAWS A FOCUS FOR VENTING
PSYCHOLOGICAL STRESS

EXAMINATION
~THIS IS A SKILL THAT MUST BE LEARNED

~If the mandible is easy to manipulate, then what
can be seen clinically is usually a fair
representation of actual discrepancy
~Large disc.-Whip Mix articulator
~If the mandible is difficult to manipulate and
there is no centric prematurity and resistance
encountered , this requires splint therapy to free
the musculature

~TMJ should be palpated for popping or
grating sounds, tenderness.
~Splint therapy & TMJ tomograms are
indicated prior to ortho. Rx
~Occlusion checked for wear facets and
look for contact areas

~Right & Left lateral excursions & protrusive
movements (interferences cannot be diagnosed
intra-orally but can be done in articulator)
~The maximum opening should be noted-
indicator of state of contracture of the
mandibular musculature – 45-50 mm

NEUROMUSCULAR CONTROL
TMJ TEETH

DIAGNOSIS & TREATMENT PLANNING
~Symptomatology splint therapy
~Intra-oral examination & Articulator
simulation
~Neuromuscular adaptations

~Records should be as close as possible to
centric relation
~Standard ortho. Models & cephalometric
headfilms have been traditionally taken in
habitual centric occlusion
~If significant discrepancy exists, records
should be taken in centric relation to
evaluate the extent of discrepancy

~In diagnosis & Rx Planning, it is necessary
to diagnose the case from a mandibular
position of centric relation, if you wish to treat
to centric relation occlusion
~The jaw relationship is corrected in all three
planes of space
~Buccolingual co-ordination of basal arches
and A-P adjustment so that there is no
horizontal overjet and there must be sufficient
closure of mandible to provide a vertical
overbite

~A true centric can never be captured on the
first clinical attempt
~True centric can be stabilized if there is no
degenerative joint changes in a non-growing
patient
~The cephalometric tomogram of the TMJ is a
good indicator of the state of the bony
elements of the joints

~Relief of symptoms alone is not the major
purpose of the splint
~To seat the condyle in the most superior
position and maintain a closed vertical
dimension
~An anterior ramp is created to disclude the
posterior teeth
~The cuspids should be the main guiding
inclines in lateral movements

~The mandibular postural changes during
splint therapy is of three types
changes due to relaxation of musculature
that postures the mandible incorrectly due
to muscle contracture or spasms
changes due to elimination of intracapsular
inflammatory fluid
changes due to remodeling or recontouring
of the bony parts of the joints

~Splint therapy is continued until there has
been no change in mandibular positioning in
centric relation for atleast three months
~If symptoms are not releived / stability not
attained, Rx is stopped
~It is wise to institute splint therapy prior to
orthodontic Rx and stabilize the mandibular
Position for three months on any
symptomatic case

REPOSITIONING
SPLINT

GNATHOLOGY

~The term gnathology denotes the science that
deals with the biology of the masticatory
system
~It referred to the science dedicated to the
study of oral cavity as a functional unity in
direct relationship to its morphology, histology,
physiology and therapy, including its vital
relations with the rest of the body
~Occlusion, Jose dos Santos

FINISHING TO GNATHOLOGICAL
PRINCIPLES
~Visualisation of
Mandibular body excursions
Tooth relationships during excursions
The effect of characteristic of the border
movement pattern on the ooclusal
morphology
Mandibular movement
Articulator movement

~We should not simply believe what we see in
mouth
~Pt. will bite where their teeth fit
~Pt. will move their mandible to avoid noxious
contact of teeth
~Muscles will contract to avoid inflicting self
injury to joints, teeth, supporting structures.
ALL THESE DENOTE THE
NEUROMUSCULAR ADAPTATION

GNATHOLOGICAL OBJECTIVES
I~CR and maximum intercuspation in that
position (No contact of anterior teeth)
II~Harmonious glide path of anterior teeth
working against each other to separate or
disclude the posterior teeth immediately

~The cuspids should be the main gliding
inclines on lateral excursion and the six
anterior teeth should articulate with the six
mandibular anterior teeth and the
mandibular bicuspids
~Mutually protective occlusal scheme

EXCURSIVE OCCLUSAL SCHEME
~The gentle lateral and protrusive lift is
necessary for both mandibular movement and
post-treatment stability of tooth positions

CLASS I vs CUSP-FOSSA OCCLUSION
~There are enough number of cusp-fossa
relationship to hold centric in Class I
~The lower buccal cusp tips rest only on one
opposing marginal ridge

THE IDEAL AND THE POSSIBLE
~Ideally centric relation and habitual centric
occlusion should be coincidental, maximum
intercuspation of teeth should occur in centric
relation which is less than 1%
~Treat the orthodontic case where there is no
discernible discrepancy between CR and CO

IDEAL TOOTH POSITIONING
~A centrically related occlusion and a
mutually protecttive occlusal scheme are
dependent upon
1.Proper individual tooth positioning
2.Knowing when the mandible is in centric
and when it is not
3.Co-ordination of arch form and width

4.Control of vertical dimension
5.A-P correction between mandible and
maxilla
6.Clinical awareness of excursive
interferences

1.+1 to A-Po
2.Upper incisors tip- 2-2.5 mm below the lip
embrasure
3.No more than 1mm gingival show
4.2.5 mm overjet
5.Level occlusal plane that will return to 1-1.5
mm curve

6.Curve of Wilson allowing seating of centric
cusps
7.As much as divergence from occlusal plane
from angle of eminence for excursive
clearance
8.Lower incisors point-point contact with
roots in same plane, Ma incl.-2 degrees
9.Lower cuspids – 5 degrees mesial
angulation with incisal tip 1mm higher than
laterals, exa. Mesial rotation in extraction
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10.Lower bicuspids uprighted 1 degree from
their normal mesial inclination and slight
distal rotation
11.Lower molars-uprighted 1 degree from
normal 2-degree mesial inclination and slight
distal rotation
12.Lower buccal segment-progressive torque
close to Andrews

13.Upper molar-Andrews
14.Upper bicuspids to 0 degrees from 2 with
some distal rotation in extraction case
15.Upper cuspid-11-13 deg mesial tip, contact
point adjacent to lateral incisors and bicuspids
for proper cuspid guidance
16.Central & lateral – 0.5mm differential, 9 & 5
deg. Mesio-axial inclination

There should be sufficient torque such that six
upper anterior teeth can contact six lower
anterior teeth and the upper cuspids can lift off
the lower bicuspids in a protrusive excursioin
17.No rotations or spaces, buccal segements
non-progressive 14 deg. Buccal root torque
18.Arch form-5 separate radii.
Widest point upper arch-MB cusp Max Molars
lower arch-MB cusp lower molar &
first bicuspids

Settling into centric relation and ideal
intercuspation is essential because
1.Tooth movement after appliance removal
2.Curve of Spee
3.Distal tip rather than mesial tip
4.Buccal segments tip & rotate mesially
5.As band space closes =loss of torque in
anteriors

6.Teeth adjacent to extraction site will tend to
rotate towards the extraction site
7.Tip towards extraction sites
8.Maxillary lingual cusp hanging
SIX KEYS

Mandibular hinge axis
Stuart Pantographic
recorder

CR-CO MOVEMENTS

IDEAL FUNCTIONAL OCCLUSION

Treatment Priorities
Completing lower arch Rx before upper
arch (finishing lower arch within a year)
Detailing of tooth positions (individual
considerations)

~Molar Fulcrum
TPA with Headgear
Compensating curves in UAW
Rectangular wires to control torque
Short vertical elastics
~Overcorrection
Held upto three months
Elastics & Headgear discontinued for 2-3
weeks
Braided rectangular wires
Pt. seen at weekly basis

Rt. & Left Excursions, protrusive
excursions-smooth gliding movement with
cuspids and anteriors in contact
The glide should be smooth and slow if the
cuspid guidance is correct and there are
no excursive interferences

FINISHING IN CENTRIC RELATION
1. Correct A-P jaw relationship. (Overcorrect,
then hold, ther settle back.)
2. Eliminate molar fulcrum.
3. Coordinate arch widths and arch form with
mandible in centric relation.
4. Buccolingual axial inclination of posterior
teeth. Lingual crown torque of 76^67
5. Watch cuspid heights and midline or lateral
deviation.
6. Level curve of Spee through second molars.

7. Check for centric deflection.
A. Prominence of lower bicuspids.
B. DB cusp upper 1st molars with MB and
D cusp on lower 1st molars.
C. ML cusp upper 1st molars with ML cusp
lower 1 st molars.
8. Marginal ridge heights.
9. Rotations

AFTER CENTRIC IS OBTAINED
Check tooth detailing (by having patient to
go through test excursions — right lateral,
left lateral,protrusive) for:
1. Torque of upper incisors.
2. Artistic tip of upper incisors and
cuspids.
3. Overbite and overjet.
4. Flatness of curve of Spee.
5. Second molar positions.
6. Look for anterior group function,
posterior clearance (minimal),
cuspid guidance, and balancing
interferences. www.indiandentalacademy.com

BITE REGISTRATION
GNATHO-POSITIONER

ARTICULATED MODELS

1. To treat to centric the case must be diagnosed
from centric.
2. The case must be constantly monitored in
centric throughout treatment.
3. The operator must have sufficient experience to
be able to recognize when his patient is not in
centric.
4. The operator must know how and when to use a
repositioning splint to find centric.
5. Treatment mechanics should be employed that
will not tend to create a centric "fulcrum"
6. The operator should have a very clearcut image
in his mind of where each and every tooth belongs
from a functional standpoint, and why it belongs
there.

7. The operator should have an "End of
Mechanotherapy Goal" from which teeth will
tend to settle most favorably.
8. The orthodontist must be able to apply the
excursive border movements clinically, to
determine proper mandibular position and
individual tooth position.
9. The use of a carefully and properly
constructed gnathological positioner will aid in
achieving the most ideal functional occlusion
on a case that is basically treated close to
centric relation occlusion with orthodontic
appliances.

THANK YOU

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