Functionally generated path occlusion final

1
FUNCTIONALLY GENERATED
PATH OF OCCLUSION
Presented by –
Dr Mujtaba Ashraf
MDS -III

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1. INTRODUCTION
2. FUNCTIONALLY GENERATED PATH OCCLUSION IN FPD
3. FUNCTIONALLY GENERATED PATH OCCLUSION IN
COMPLETE DENTUERE
SINGLE COMPLETE DENTURE
REMOVABLE PARTIAL DENTURE
6. ADVANTAGES.
7. DISADVANTAGES.
8. CONCLUSION.
CONTENTS:

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OCCLUSION:
It is defined as-
1. The act or process of closure or being closed or shut off,
2. The static relationship between the incising or masticating surfaces of
the maxillary or mandibular teeth or tooth analogues. (GPT-8)
Dental articulation:
Dental articulation is defined as the static and dynamic
contact relationship between the occlusal surfaces of the teeth
during function.

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Early concepts were based on those of:
Bonwill (1858)
Balkwill (1866)
Von Spee(1890)
Then came the age of occlusal theories and
occlusal articulators which include:
1.Monsons spherical theory(1916)
2.Halls conical theory(1918).
3. Meyers functionally generated path technique(1940)
CONCEPTS OF OCCLUSION:

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NATURAL DENTITION OCCLUSION.
1. Mutually protected occlusion or
canine protected occlusion. (D’AMICO)
2. Group function occlusion. (SCHULER)

INTRODUCTION:
To properly evaluate a patients occlusion it is mandatory
that diagnostic casts be placed /articulated in the same
relation as in the patients mouth.
The method of reproducing centric and eccentric relations
between the maxilla and the mandible for the fixed or
removable reconstruction can be divided into two groups.
1. Methods using articulators.
1. Methods using functionally generated Path technique
(FGP)
6

Dentistry has recognized functional path
articulations as a viable way of developing occlusion for
more then 60 years .
Meyers first described this method in 1933, as a
means of obtaining the “Functional Occlusal path” for
bridges fabricated by a direct/indirect technique and for
dentures.
7

Functionally generated path relies on recording in a
simple, yet precise manner the pathways traveled by the cusps
in the border movements of the mandible. Wax is adapted over
the occlusal surface of the prepared tooth. The patient occludes
the teeth in the intercuspal position and moves the mandible
through all excursions .By this process the tips of the opposing
cusps acts a recording styli that carve , in three dimensions in
wax, a record of the border movements in all mandibular
positions.
Stone is brushed and poured into the wax record in the
mouth to produce functional core. The stone core is then used in
the fabrication of posterior tooth restoration.
8

• The technique was adapted for use in COMPLETE
OCCLUSAL REHABHILITATION by PANKEY AND MANN.
• Here based on the Spherical theory of occlusion,
calipers are used to locate a center of rotation. From this
center , the mandibular cast is reduced to bring the occlusal
surface of the mandibular teeth in to harmony with the surface
of the theoretical sphere, with a uniform amount of reduction
(1.6 mm).
9

•After the mandibular teeth in the mouth have been
reduced and subsequently restored to an ideal plane, an
functionally generated recording of the mandibular cusp
path is made. It is used to produce a stone functional
core or index against which the maxillary restoration are
fabricated.
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Armamentarium for the FGP
Petrolatum
Cotton-tipped applicator
Cavity varnish
Tacky wax
PKT waxing instruments
Bunsen burner
Die fabricant
Mounting stone
Spatula
Plaster bowl
Sable brush
Functional index try
Laboratory knife with no 25
blade
Custom impression tray
Impression material (base
and accelerator)
Mixing pad
Syringe
Bite registration frame
Bite registration paste
Die stone
Di-lok tray
Twin stage occluder
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PROCEDURE FOR THE FABRICATION OF FUNCTIONAL
CORE FOR FIXED PROSTHODONTICS :
( Functional index or Counter die)
• The working side tooth contacts is evaluated to
determine whether they form a mutually protected occlusion
(canine guide occlusion) or unilaterally balanced (group
function) occlusion, which is essential in determining the type
of occlusal scheme to be produced in the final restoration.
• The technique to be described here is primarily for use
in fabricating restorations in maxillary teeth.
12

The preparation for the
cast restoration is started by
doing the occlusal reduction.
Before preceding on to
the axial reduction the functional
tracings are made.
The larger occlusal table
that is present before axial
reduction will afford greater
stability to the wax tracing.
13

Petrolatum is applied with
a cotton tipped applicator to the
occlusal surface of the opposing
quadrant and cavity varnish is
applied to the occlusal surface of
the prepared tooth to help the
wax to adhere more securely.
Piece of wax is cut in a square slightly larger than the
occlusal surface of the teeth being restored.
The square of wax is attached to a PKT No.2 waxing
instrument and soften it over bunsen burner flame.
While the varnish on the occlusal surface is still tacky
and the wax is soft, tack the wax is to the tooth being
restored.
14

The patient is guided
into a retruded closure in
centric relation. Then patient
is guided through all
excursions, moving first into
the working side .
From working
excursion, the patient is
guided back to centric relation
and then into a nonworking
movement.
15

Have the patient return again
to centric relation and then to
protrusive.
The patient should be guided
through combination movements as
well : working protrusive and non
working protrusive .
Finally the patient should just
“mill around” to ensure adequate
clearance
For the opposing cusps in function.
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TO OBTAIN THE FUNCTIONAL CORE.
A tray of some sort should be used to hold the stone in
place in the mouth to make the functional core.
Tongue blades and denture tooth cards can be
employed for this purpose, but a functional index tray offers
definite advantages.
• It is curved to fit the arch.
• Has undercuts to hold the stone in
position.
• The tray extends to the anterior teeth
for added stability.
• The unneeded portion
can be broken and discarded.
20

The wax is painted with a die lubricant to reduce surface tension
and ensured a smooth, complete functional core.
A creamy mix of mounting stone is painted on the surface of the
functional wax tracing with a sable brush
The functional index tray is loaded with a layer of
mounting stone 6.0 mm(0.25 inch) thick. Position it on the
occlusal surface of the quadrant so that it covers at least
one tooth on each side of the prepared tooth. 21

When the stone has set, it is removed carefully and
examined carefully for free of bubbles or voids .
This stone replica of the movement of the cusp tips is
called the functional core. It is also referred to as the
functional index or counter die.
The surface of the core is trimmed with a sharp
laboratory knife.
The rest of the tooth preparation is completed and
an impression of the quadrant containing the prepared
tooth is made using a custom acrylic tray made
previously. 22

It is possible to fabricate a restoration using only
the functional core for an opposing model. However it is
very helpful to have an anatomic cast against which you
can occlude the wax pattern.
For this an occlusal registration is made at the
intercuspal position using bite registration paste in a bite
registration frame.
23

Attach the quadrant tray with the mounting stone to the lower
member of an articulator with two upper members. Trim the
base of the cast containing the prepared tooth also the cast will
fit into the die tray. The finish line of the the tooth preparation
should be about 0.25 inch above the edge of the die tray
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TO ATTACH THE FUNCTIONAL CORE IN TWIN STAGE
OCCLUDER.
Dental stone is poured into the imprints of the
mandibular teeth in the disinfected Zinc oxide eugenol bite
registration and base is created approximately 0.5 inch thick
on the occlusal registration. Undercuts are left on the base
for the later attachment to the articulator.
25

Now the functional core is placed on the cast in the die tray
and confirmed that it still fits accurately. It is attached to the
cast with the sticky wax.
The incisal pin of the twin stage occluder is adjusted.
The functional core is now mounted on the upper
right member of the articulator
26

TO ATTACH THE ANATOMIC CORE IN TWIN STAGE
OCCLUDER.
On the maxillary side of the zinc oxide eugenol bite registration
small fins are trimmed that fit into the occlusal embrasure between the
teeth. Carefully the bite registration is fitted on the cast of the di-lok tray.
It is ensured to seat properly without any rocking or wobbling and after
adjusting the incisal guide pin the anatomic cast is mounted to the left
upper member with mounting stone.
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•Sawing of the die is done.
•Ditching
•Gingival finish line marked in red pencil
•The die and the sections of the quadrant cast is
reassembled
•The mounting is ready for wax pattern fabrication.
30

The verticulator is another instrument that is made for
use with the functionally generated path technique. It is
extremely rigid and provides a precise alignment of cast and
functional core. It also utilizes a second upper member
(removable not hinged) that can be employed with the
anatomic cast.
A plane line hinge articulator can also be used for this
purpose, but it does not permit the use of an anatomic cast.
31

Wax pattern fabrication
The die is removed from the di-lok tray and the preparation is
lubricated thoroughly with die lubricant.
Wax is flowed over the surface of the preparation on the die using
quick, overlapping strokes of a hot no. 7 wax spatula.
Initially the occlusal portion of the wax pattern should be waxed
against the anatomic cast to aid in visualizing cusp location more effectively.
The wax added technique is used to position the cones of the cusp
tips. Marginal ridges and cusp ridges complete the outline of the occlusal
table, and then they are blended into the axial contours. Triangular ridges are
placed next.
32

Axial contours and proximal
contacts are checked before
preceding to the
occlusal surface.
The wax added technique is
used to form the occlusal
morphology.
33

Now the occlusal portion of the
wax pattern can be completed by waxing
against the functional core.
34

White liquid shoe polish is painted on
the functional core. The articulator is closed
so that the functional core is brought in
contact with the occlusal surface of the wax
pattern.
The shoe polish will leave white marks
on the occlusal surface of the wax pattern
corresponding to the contacts in function. Any
areas in white that are not part of the of the
desired centric or excursive contact pattern
are carved off according to the restoration
which would go to mutually protected or
group function occlusion.
35

If the restoration should be in
mutually protected relationship there
should be no contact on the lingual incline
of the buccal cusp other than the centric
contacts.
If on the other hand the restoration
to be fabricated in group function, the
lingual incline of the buccal cusp should
maintain continuous contact with the
functional core.
In no case should the non working
inclines have any contact with the
functional core. 36

FUNCTIONALLY GENERATED PATHWAY FOR THE
COMPLETE DENTURES.
The functionally generated path technique has
been successfully adopted in the construction of complete
denture prosthodontics. The object is to obtain the
individual curves of a patient.
Briefly this is attained by inserting record blocs
with abrasive rims and allowing the patient to grind them
together untill they are in balanced articulation.
This type of record is very suitable for patients with
marked translatory movements of the mandible. 38

OCCLUSAL RIMS:
Generally the occlusal rims for complete denture are
made up of
1. Wax
2. Impression Compound
3. Mixture of plaster with an abrasive such as pumice
and sand.
39

RECORD BASES AND OCCLUSAL RIMS
Stability of the record bases is essential for accuracy since
there will be a considerable lateral and protrusive drag to friction,
during the process of grinding
Ideally the denture bases is made up of heat cure acrylic
resin. The occlusal rims are made up of plaster and an abrasive, such
as coarse corborandum, pumice or sand
The buccolingual width should be about 1 cm, which is
necessary to define the lateral and antero-posterior curves and for
strength.
40

RECORDING THE FUNCTIONAL PATH
` Tentative jaw relations are first recorded with wax blocks and
mounted in semi adjustable articulator.
The blocks with abrasive rims are then constructed with the
vertical height opened a few millimeters to allow for the closure which
will result from the grinding.
One method of constructing the rims is to make them of
composition within 5 mm of the estimated correct height, to groove the
composition for retention and then build up the plaster pumice for a
further 4-5 mm.
41

The record bases are placed in the
oral cavity. The patient is instructed to
grind the blocks together with both lateral
and protrusive movements but only to use
the minimum pressure necessary to keep
the blocks in contact.
The grinding is continued until the
correct vertical dimension is obtained.
42

The occlusal surfaces of the rims now
show correct balancing curves for the patient.
The curves are reproduced in the
denture by mounting the casts on a plane line
articulator and setting the lower zero cusp
teeth to occlude with the upper block and then
the upper teeth to occlude with the lower ones.
The form of cusp will vary with the
height of the occlusal surfaces and also with
the original shape of the plaster pumice blocks
whether flat or curved.
43

FGP OCCLUSION FOR SINGLE COMPLETE DENTURE:
Whenever the irregularity of the occlusal table of the
natural teeth is only mild it is best treated by a functionally
generated path technique.
In such a case acrylic posterior teeth is used and
the occlusion is built on the articulator as for as possible.
Now mesio-distal channels are cut out and the upper
denture teeth are reduced out of contact with the teeth on
the lower cast.
The channels are filled with impression compound
and centric stops are made.
The remainder of the denture teeth are built with the
hard wax on the articulator. 44

The denture is placed in the patients mouth and the
patient is instructed to make movements towards working,
nonworking and protrusive excursions to shape the wax to
these eccentric contacts.
In the laboratory occlusal registers are poured.The
hard wax and compound is removed and is replaced with
the casting wax
The casting wax is sprued and casted in gold alloy.
The castings are polished and then attached to the denture
with EBA (Orthoethoxybenzoic acid) cement to obtain gold
occlusal denture teeth
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FUNCTIONALLY GENERATED PATH TECHNIQUE FOR RPD:
The theory on which the FGPT is based is that “the
pathways each tooth opposed to the edentulous space
makes throughout all functional movements of the mandible
are recorded, the artificial tooth may be positioned and
formed so that it will remain in harmonious contact with its
antagonist at all times.
46

The pathways are created by the patient in a wax occlusal
rim. The patient performs all functional excursions while
the opposing teeth contact the surface of the occlusal rim.
The recording produced is actually a negative record of the
movement of each opposing tooth as the mandible
executes the functional movements.
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ADVANTAGES:
FGPT eliminates the need for adjusting articulator with interocclusal
records or a tracing device
The excursive movements produced in the mouth are more accurate
than those in an articulator.
It eliminates the need of face bow transfer.
Is simple and can produce precise excellent results.
48

DISADVANTAGES:
1. The occlusion in one of the arches must be complete before
functional generated path can be developed.
2. This cannot be effectively utilized for CD opposing RPD.
3. The movement of distal extension base carrying hard inlay wax
occlusal rim is usual.
4. Verification of record in mouth is difficult. 49

CONCLUSION:
The method of interocclusal registration using the articulators is
time consuming, expensive and technique sensitive. Whereas in the
FGP technique dynamic and static relations are reproduced directly in
the mouth to capture the pathways traveled by the opposing cusps in
mandibular function.
In this situation the articulator is reduced to a role of a simple
hinge. It is a relatively easy technique to learn. The technique does have
the advantage of permitting simple, inexpensive instrumentation for
restoration of teeth. I demands a minimum of chair time, especially
during the try in and cementation phase.
50

REFERENCES:
1. Okeson:Management of temperomandibular disorders and occlusion Ed 3 St Louis
1993, Mosby
2. Bernard G.N. Smith: Planning and making crown and bridges.
3. Davis Hinderson: Mc crackens removable partial prosthodontics.
4. Dawson P.E: Evaluation, diagnosis and treatment of occlusal problems.
5. Dykema P.E. Johnston’s modern practice in fixed prosthodontics.
6. Earnst L. Miller: Removable partial prosthodontics.
7. Glossary of Prosthodontic terms. JPD Dec 1984.
8. Hamish Thomson: occlusion.
9. Herbert T. Shillingburg: Fundamentals of fixed prosthodontics
10. Hobo Sumiya: Osseeointegration and occlusal rehabilitation.
11. Ramford S and Ash M: occlusion.
12. Robert P Renner: Removable partial dentures
13. Stephen.R. Rosensteil: Contemporary fixed prosthodontics
14. William F.P. Malone: Tylman’s Theory and practice of fixed prosthodintics.
15. BDJ Series of articles on occlusion, 2000 51

Functionally generated path occlusion final

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