Interocclusal records (2)/endodontic courses

INDIAN DENTAL ACADEMY
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
An interocclusal record is a precise recording
of a maxillomandibular position.
 In dentate subjects it may be made in a
closed occlusal contact or in an open
nonocclusal contact position.
There may be a slight separation of the
opposing teeth when a closed occlusal
position is recorded, because of impression
material obstruction.
Introduction


 . It is particularly indicated in situations of
abnormally related jaws , supporting tissues that are
excessively displaceable , large tongues , &
uncontrollable or abnormal mandibular movements.
 It is also used to check occlusion in existing dentures
& in trial dentures .


Inter occlusal record : registration of the
positional relationship of the opposing teeth or
arches
 A record of the positional relationship of the
teeth or jaws to each other.
Centric inter occlusal record- a record of centric
jaw position
Definitions


 Eccentric inter occlusal record – a record of jaw
position other than centric
 Lateral –record of lateral eccentric jaw position
 Protrusive – record of protruded eccentric jaw
position .


ANATOMIC HARMONY
 Proper functioning of any system requires all its
respective components in their respective places
 Any thing that interferes with static harmony of any
part alters normal muscle function into an
unbalanced relationship of constant demand .
 Most common shortcoming is the failure to consider
all parts of the masticatory system as one entity
AIM OF RECORDING


FUNCTIONAL HARMONY
 Goal of functional harmony is a peaceful
neuromuscular system
 Stomatognathic system is highly organized
relationship to each other and to the teeth, which fits
into the system without disturbing any of the other
functional demands
 Knowledge of functional interdependencies is
required to understand cause and affect influences in
the dentition or the joints


OCCLUSAL STABILITY
 Teeth are the most adaptable movable part of the
masticatory system
 Forces exerted against teeth easily alter their
position, either vertically or horizontally


 Centric inter occlusal records
 Eccentric inter occlusal records
 lateral inter occlusal records
 protrusive inter occlusal records
Types of inter occlusal
records


Active techniques:
 This retruded mandibular position is assumed of the
patient without the examiner:
Swallowing or free closure
Tongue to palate
Methods to Guide the mandible to centric relation in
dentulous situation


 Passive techniques:
 The examiner without the conscious cooperation of
the patient makes Retruded mandibular position.
 Chin point guidance
 Methods with anterior stops
 Lucia Jig
 Long Leaf Gauge
 Central Bearing Point
 Bilateral manipulation


Swallowing or free closure:
 The patient is instructed to close slowly on his back
teeth or to swallow and close his mouth, guiding his
teeth to contact and maintaining it in that position.
 It was however noted that this method consistently
gave the most variable or least consistent results as
well as giving the most protrusive records of all
methods.
Active techniqe


Tongue to palate:
 The patient was instructed to touch his palate as far
distally as possible with the tip of the tongue and to
hold it in this manner while he closed.
 The major problem associated with this technique is
that a lot of the patients find this maneuver difficult
to perform.


Chin point guidance:
 The dentist holds the patients chin firmly between
his thumb and index finger in the midline and exerts
a firm pressure in a postero inferior direction during
closure.
 Though this gives one of the most retrusive records,
it has a tendency to push the condyles down and
back.
 This method too is not very consistent in its
recordings.
Passive technique


 One hand chin point guidance technique


ANTERIOR STOPS
The two principal methods of using
anterior stops are those of
LUCIA JIG advocated by Lucia
LEAF GAUGE advocated by Long.


The problem of these techniques are associated
with the use of anterior stops, as they have a
potential for deviating the mandible
if not properly used




Central bearing point
 A central bearing point as used in pantographic or
stereographic techniques is an excellent muscle-
deprogramming device that allows the elevator
muscles to seat the condyle in the proper direction.
It also prevents any chance of mandibular
displacement due to occlusal contacts.


Guides the mandible in the most superior anterior position
 Consistently repeatable
 Most easily learned
 It provides a method of verification of –
 Correctness of condyle position
 Alignment of condyle disk assembly
 Integrity of articular surfaces
 The ability to exert firm pressure upward while the teeth are separated is
the key for verification.
 Also, the comfort and ablity to slowly hinge the mandible.
Bimanual method/
Dawson technique


DIFFICULTIES IN RETRUDING THE
MANDIBLE
One of the most difficult and most important tasks is
retruding the mandible to its centric relation. Some of
the difficulties encountered are:
1. Biologic
2. Psychologic
3. Mechanical


 Biological causes-
 Lack of coordination between the groups of
opposing muscles when the patient is requested to
close the mouth in retruded position
 Habitual eccentric jaw relation


Physiological causes-
 Inability of the patients to follow dentist’s instructions
 Overcome by instituting stretch relax exercises, training
the patient to open and close his mouth etc
 Central bearing devices can also be used in these patients
Mechanical causes
 Poorly fitting denture bases
 Checked with a mouth mirror for proper adaptation.


 Benjamin Braly’s Classification
 Class I :
 Single crowns
 Fixed partial dentures in which the existing occlusal
position is maintained
 Simple articulating devices to follow wear facets on
the teeth. Coe checkbite tray for making records
 Functionally generated path technique
Principles For Selecting
Interocclusal Records


 Class II :
 Needs changes in arch form, tooth form, or occlusal position
 Repositioning, reshaping, or occlusal adjustment
 Correction of occlusion disharmonies converts into Class I situation
 semiadjustable articulator
 Class III
 No reliable guides of tooth form or occlusal position remain
 Requires full mouth reconstruction
 Fully adjustable articulator
 chew in procedure
 A pantographic tracing device


 The factors that ought to be considered before the selection of
the technique or the material for the procedure are: -
1.The ability of operator to manipulate the mandible
 In case the operator has perfected the manipulative techniques
so that a quick position can be arrived at and be able to
successfully close it without deviating into the bite material
then wax may be chosen as a suitable record material.
 In case the procedure requires too much time then the wax will
cool and become too hard.
 Unless the wax is exceptionally soft there is always a danger of
depressing the teeth or moving them laterally.


 The patients ability to cooperate
 This will be a hindrance factor till the manipulative
techniques are perfected and the trust ascertained. Except
for special or unusual cases where this might be difficult
to derive upon.

 Tooth mobility
 It is mandatory that the tooth should not be moved by the
bite material. Mobile teeth might warrant stabilization
before a correct bite can be registered. In such cases soft
materials that do not depress or displace the teeth should
be used.


 Edentulous areas
 While recording the bite, care must be taken to note that the
material does not distort the soft tissues. A model made
from a non distorting impression material will not fit into an
inter occlusal record that has compressed the soft tissues.
Condylectomy
 The procedures to be followed for patients who have been
deprived of one or both condyles are entirely different from
the procedures used for recording the terminal hinge
position of the condyles.



Occlusal interferences
 In a patient with existing gross interferences it will
demand the use of different procedures to register the
centric relation record as compared to a patient with no
occlusal interferences at the established vertical
dimension in order to avoid the deflective contact. In fact
the recording might have to be made at an open vertical
relation to avoid contacting the interferences.
 In such cases precautions ought to be taken to ensure the
correct recording of the terminal hinge axis along with the
interocclusal record.


INTEROCCLUSAL REGISTRATION
MATERIALS



Limited resistance before setting to avoid
displacing teeth or mandible during closure.
Rigid after setting
Minimum dimensional change
Accurate record of incisal & occlusal surfaces
Easy to manipulate
No adverse effect on tissue
Records should be verifiable
Characteristics of ideal registration
material


 According to Dawson, the criteria for accuracy in
making interocclusal records include the following
points:
 1. The recording material must not cause any
movement of teeth or displacement of soft tissues.
 2. The recording material must fit cast as accurately
as it fits the teeth intra-orally.
 3. The accuracy of the jaw relation record should
check in the mouth and on the casts


 Impression plaster
 zinc oxide eugenol
 waxes
 elastomers
 acrylic resins
 Impression compound
Materials


 Type 1 modified with addition of accelerators to decrease
setting time & setting expansion
Advantages:
 Accurate
 rigid after setting
 Do not distort with extended storage.
Disadvantages:
 Difficult to handle
 Brittle.
 Difficult to handle ,
 record is brittle .
Impression plaster
(soluble plaster)

Ease of manipulation ,
 Inaccurate ,unstable ,inconsistent , may interfere with active &
passive movements
Bite registration waxes
Advantages:
Ease of manipulation.
Disadvantages:
Inaccurate
Unstable
Inconsistent


Zinc oxide eugenol paste
• advantages:
Fluidity Adhesion to its carrier
Rigidity and inelasticity after final set
Accuracy in recording occlusal and incisal surfaces of the teeth
High degree of repeatability.
• Disadvantages:
Lengthy setting time
Significant brittleness
The accuracy of the registration material may surpass
the accuracy of the casts, resulting in improper fit.
Brittle(vital portion may be lost by breakage)
Sticks to tissues www.indiandentalacademy.com

Addition and condensation silicones
Silicone elastomers
Advantages:
Accuracy
Stability after setting
Minimal resistance to closure
Does not require a carrier
Disadvantages:
Resistance to compression


Acrylic resin
 Used for fabrication of single stop centric occlusion records.
Advantages:
 Accurate and rigid
Disadvantages:
 Dimensional instability due to polymerization shrinkage.
 The strength and rigidity of the material can damage plaster
casts and dies during articulator mounting.


 impression material augmented by plasticizers and fillers
Advantages:
 Good Accuracy
 Stability
 Fluidity and minimal resistance to closure
 It Can be used without a carrier
Disadvantages
 Resiliency
 Accuracy may exceed the accuracy of plaster casts.
 Interferes with the placement of plaster casts (The records are trimmed to
remove excess material and preserve only the teeth indentations, avoiding
distortions)
Polyether Elastomers


Impression compound type I
uneven softening of material,distortion and inability
to reproduce details accurately.


CLASSIFICATION OF INTEROCCLUSAL
RECORDS
 There are two basic categories of interocclusal
registrations
 Centric registrations.
 Eccentric registrations.


These can be further categorized as follows:
 Centric registrations.
 Centric occlusion records.
 Centric relation records.
Eccentric registrations.
 Lateral exclusive records (lateral check bites).
 Protrusive records (protrusive check bites).
 These registrations are accomplished with various
materials and techniques


 The use of wax for making interocclusal records
is the most popular method. The main reason for
using this technique is it fulfills all criteria for
accuracy.
WAX BITE
PROCEDURES


 One of the biggest advantages of the wax record is
that it can be checked in the mouth as well as in the
models.
 It becomes extremely hard when cooled in ice water
.
 Re softening the lower side and then repeating the
closure in CR can correct minor discrepancies very
easily.
ADVANTAGES OF WAX BITE REGISTRATIONS


 These records are highly technique sensitive and
their accuracy depends largely depend on the
operators ability to toe the line
 Wax records easily undergo distortion if not stored
properly thus resulting in an incorrect maxilla
mandibular record
 All waxes have a definitive body and if not softened
adequately prior to the procedure they will cause
displacement of the teeth and there by registering an
incorrect record.
DISADVANTAGES OF WAX BITE REGISTRATIONS


 The use of an appliance called the anterior jig as
described by Lucia and it mainly employed as an anterior
deprogramming device.
 Anterior stop techniques may be modified and adapted
to almost any clinical situation in which anterior teeth are
present.
 It is an extremely accurate technique, and the accuracy
can even be achieved with very loose teeth, posterior
edentulous ridges, and patients with temporomandibular
joint problems.
ANTERIOR STOP TECHNIQUES


 The stop should be thin enough so that the first point of posterior
tooth contact just barely misses, but under no circumstances
should any posterior tooth be allowed to touch when the anterior
stop Is in place.
 The great advantage of using an anterior stop is that it allows the
condyles to seat up without any possible deviation or restriction
from the posterior teeth.
 Variations in the technique are mostly variations of materials used.
As an example, the anterior stop may be made from acrylic resin or
from hard compound. It may be processed on previously mounted
models, or it may be adapted directly in the mouth.


 It is preferable to make the jig on an upper study
cast. Some clinicians make it in the mouth, but this
can be dangerous because of the heat generated
when the self-curing plastic cures.
CONSTRUCTING THE JIG


DELAR WAX IS USED


 To direct the occlusal forces along long axis of the
teeth.
 To attain simultaneous contact of all teeth in centric
relation
 To eliminate any occlusal contact on incliner planes
to enhance the positional stability of the teeth.
 To have centric relation coincide with maximum
intercuspation position.
 To arrive at the occlusal scheme selected for the
patient [unilateral balanced vs. mutually protected]
To conclude
IMPORTANCE OF
RECORDS


 In the absence of the patient casts will provide us a
great information if they are articulated properly for
this a good interocclusal record is needed
 When the distal most tooth in the arch is an
abutment
 When 1 or 2 areas if tripod is missing when
articulating the casts
 To check for any centric interferences in patients
Contd.......


 1. Herbert. T. shillingburg 3rd edition
 2. Peter. E .Dawson 2nd edition
 3. Stephen . F. Rossensteil 3rd edition
 3. An improved interocclusal record of centric
relation Carl G. At all. J. Prosth. Dent.March, 1971
 A Simplified Technique for Making an Interocclusal
Record in Fixed Prosthodontics. J. Prosth. Dent,
August 2005
bibliography

Interocclusal records (2)/endodontic courses

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