Dent Clin N Am 48 (2004) 471486

Jaw relation records for xed prosthodontics

Rachel S. Squier, DMD, MDSc
Department of Prosthodontics and Operative Dentistry, University of Connecticut
School of Dental Medicine, 263 Farmington Avenue Farmington, CT 06030-1615, USA

Jaw relation records are a fundamental and crucial component of pro-

viding accurate, high-quality xed restorations. A disciplined and ecient
practitioner understands that the use of accurate records minimizes the
need for intraoral adjustments before prosthesis delivery and can there-
fore reduce overall treatment time and cost. Because all dental materials
have their inherent limitations and because there exists variability in intra-
oral conditions, learning to minimize discrepancies in making jaw relation
records is critical.
This article reviews the concepts of jaw relation records (or interocclusal
records) and discusses the selection of interocclusal records for a variety of
clinical situations. In addition, articulator choice, the purpose of a facebow,
and materials for jaw relation records are discussed. Some pearls are
oered to help avoid common problem areas, including making impressions,
pouring impressions, mounting casts, and making interocclusal records.

General principles
If the goal of restorative treatment is to maintain a patients pretreatment
intercuspation and vertical dimension of occlusion (VDO), casts should be
mounted in a manner that maintains the same tooth-to-tooth relationship
that existed before treatment. This maximum intercuspal position (MIP)
facilitates treatment and works with the patients existing occlusion. The
vast majority of cases treated fall within this MIP category. The situation
becomes more dicult if a patient requires extensive treatment or if the
VDO needs to be altered. In these circumstances, a reproducible maxillo-
mandibular position from which treatment is performed is essential and

E-mail address: squier@up.uchc.edu

0011-8532/04/$ - see front matter 2004 Elsevier Inc. All rights reserved.
doi:10.1016/j.cden.2004.01.001
472 R.S. Squier / Dent Clin N Am 48 (2004) 471486

requires a centric relation record made at the terminal hinge axis. This
article deals with situations where the patients MIP and VDO do not
change as a result of treatment.

Function of the jaw relation record

Jaw relation records, or interocclusal records, have the following functions:
(1) They provide the stability or support that the casts of the remaining
dentition lack, (2) they reduce chair time for the delivery of the restoration, (3)
they reduce the likelihood of making restorations in hyperocclusion or with-
out occlusal contacts, and (4) they reduce the chance of perforation of re-
storations being inserted with excessive adjustment or having to adjust the
opposing dentition inappropriately.
For opposing casts to relate well, there must be a tripod of vertical support
and horizontal stability between the two casts. A minimum of three widely
spaced tooth-to-tooth contacts should be present during mounting to ensure
adequate stability. Casts that rock or wobble due to an insucient tripod
require an interocclusal record to stabilize them before mounting. Full-arch
working and opposing casts frequently have sucient occluding natural teeth
to accurately position the casts in a stable MIP occlusion, and horizontal
stability is generally present when there is good intercuspation between teeth.
However, in a patient with worn occlusal surfaces, although a solid vertical
tripod may be obtained, the horizontal stability may be inadequate to
accurately mount the casts. The goal of the interocclusal record is to provide
the support or stability that the casts of the remaining dentition lack.
Interocclusal records used to mount casts in MIP can be separated into
two categories: (1) records made when a tripod of vertical support is avail-
able from the remaining tooth-to-tooth contacts (an existing tripod inter-
occlusal record) and (2) records made when a tripod of vertical support is
not available from the remaining tooth-to-tooth contacts (a created
tripod interocclusal record) [1].

The existing tripod interocclusal record

When there is a tripod of widely spaced contacts and good intercuspation
of the teeth, an interocclusal record is not needed. In this situation, hand
articulation is the most accurate means of mounting a mandibular cast to
a maxillary cast. Practitioners frequently waste time and materials making
an interocclusal record when one is not needed. In addition, the use of an
interocclusal record when hand articulation is sucient creates a potential
for error because the record can often prevent the casts from fully inter-
cuspating (Figs. 1 and 2). Therefore, full-arch impressions made for a mini-
mum number of teeth being restored usually need no interocclusal record
due to the number of intact occlusal contacts.
 R.S. Squier / Dent Clin N Am 48 (2004) 471486 473

Fig. 1. (A) An existing tripod of widely spaced contacts with good intercuspation of the teeth
does not require an interocclusal record. (B) An interocclusal record was unnecessarily made
and will most likely prevent the two casts from articulating well.

In patients where vertical support is adequate but horizontal stability is

lacking, an interocclusal record is needed to mount casts. Elastomeric
materials such as polyvinylsiloxane are ideal for making interocclusal
records where only horizontal stability is needed [2,3]. However, their
accuracy can be compromised if they are not properly trimmed. These
records should be carefully trimmed to remove all areas of the record that
contact soft tissues and the axial surfaces of the teeth (Fig. 3). This is done to
minimize the areas where the casts and the record touch, allowing the
practitioner to visualize how the casts seat into the record and ensuring that
the record provides only the horizontal support, with the contacting teeth
providing the vertical support.
Rigid materials, such as resins or waxes, can also be used to make existing
tripod records where horizontal stability is compromised. However, unlike
the elastomeric materials, the rigid materials should be used only for
segmental records and not for full-arch interocclusal records because they
could cause an inadvertent increase in the VDO if used incorrectly. These
rigid materials require adequate interocclusal space, such as between
a prepared tooth and its opposing teeth.
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Fig. 2. (A) An interocclusal record was made unnecessarily. (B) Removal of the interocclusal
record shows that it was not needed due to a good tripod of vertical support and horizontal
stability.

The created tripod interocclusal record

A tripod of opposing teeth is present but without occlusal contacts
A practitioner has to create a tripod of vertical support where one does
not exist to mount opposing casts. A classic example of a created tripod
interocclusal record is a fully dentate patient who has teeth #18 through #20
prepared for a xed partial denture. Although the teeth are well positioned
around the dental arch, the tooth preparations prevent the existence of the
third leg of the tripod. In this situation, the tripod has to be created so that
the working and opposing casts can be mounted accurately. The materials
best suited for this purpose are those that are soft at placement and then
become rigid before their removal from the mouth, such as waxes, resins,
zinc oxide and eugenol pastes, and impression plasters. The materials of
choice for the general practitioner are resins (DuraLay [Reliance Dental,
Worth, Illinois] or GC Pattern Resin [GC America, Alsip, Illinois]) or
waxes. Resin placed conservatively between the tooth preparations and the
opposing teeth creates the needed leg of the tripod for mounting (Fig. 4).
The practitioner should avoid the elastomeric materials for this situation
because these materials exhibit compressibility and rebound, often resulting
 R.S. Squier / Dent Clin N Am 48 (2004) 471486 475

Fig. 3. (A) An interocclusal record that has not been trimmed. (B) An interocclusal record that
has been trimmed properly on one side to remove all areas of the record that contact soft tissues
and the axial surfaces of the teeth. The other side has not been fully trimmed to demonstrate the
dierence in the amount of material needed.

in an inaccurate mounting that may lead to the need for excessive adjust-
ments upon delivery of the restoration or the possibility of no occlusion
between the restoration and the opposing teeth.

Opposing teeth are absent at one or more desired tripod stops

When teeth are absent at one or more potential tripod stops, a record
base-occlusion rim is indicated to obtain support from the edentulous ridge.
The practitioner may use a record base-occlusion rim made on a cast or can
make an intraoral segmental interocclusal record composed of rigid setting
materials that do not displace the soft tissues of the edentulous ridge at the
time of placement. If the choice is a record base-occlusion rim, the record
base must be made on the cast(s) that is to be mounted and not on earlier
made diagnostic casts [4]. A record base made on one cast does not
predictably transfer to another cast due to dierences between the casts.
These discrepancies are the result of minor dierences in soft tissue dis-
placement and tooth position and dierences from the dimensional accuracy
of impression materials and dental stones.
476 R.S. Squier / Dent Clin N Am 48 (2004) 471486

Fig. 4. Interocclusal record made with a rigid autopolymerizing resin. In a distal extension
situation, resin placed conservatively between the tooth preparation and the opposing tooth
creates the needed leg of the tripod for mounting the casts.

The record base is adapted to the edentulous portion of the cast and often
to the lingual surfaces of the remaining teeth to enhance stability and
retention (Fig. 5). Record bases usually are made from light-activated resin
or autopolymerizing resin. The occlusion rim is able to function only as
a substitute for a leg of a tripod when the record base is stable in the mouth
and on the cast. The occlusion rim can easily and cheaply be made from
baseplate wax to imprint the cusp tips of the opposing teeth, or other mate-
rials may be used, including metal-impregnated wax or the more rigid of
the elastomeric interocclusal recording materials (eg, Blu-Mousse; Parkell,
Farmingdale, New York).
If the working cast with crown preparations contains the edentulous
areas where tripod stops are desired, the record base cannot be made until
the nal impression is made, poured, and separated and the cast is trimmed.
This usually requires that the patient make a separate brief appointment for
a jaw relationship record before fabrication of the restorations. However, if
the edentulous areas are located in the opposing arch, the practitioner who
has planned ahead may have the record base-occlusion rim made on the
opposing cast before the nal impression visit, allowing the interocclusal
record to be made at the nal impression appointment.
Because of the popularity of the elastomeric materials for interocclusal
records, they are often abused. One situation where this is the case is when
there is an absence of a tripod of support and there is a need to create the
tripod. Polyvinylsiloxane and polyether are ineective materials when
creating a tripod of support due to their inherent compressibility. Although
the materials are easy to use for interocclusal records, their use during the
mounting of the casts can be technique sensitive. It is dicult to objectively
determine the amount of force that should be exerted on the casts when
mounting them with the interocclusal record. Too much force can cause
compression of the elastic record, resulting in some part of the casts placed
 R.S. Squier / Dent Clin N Am 48 (2004) 471486 477

Fig. 5. (A) A light-activated resin record base with wax occlusion rim for making an
interocclusal record. (B and C) Light-activated resin record bases with respective interocclusal
records made in an elastomeric recording material. Note how the record bases are supported by
the lingual surfaces on the remaining teeth and that a minimum of recording material is used to
record only the cusp tips of the opposing teeth.

too closely together, and too little force can allow for inadequate seating of
the cast into the record, resulting in casts that are too far apart. Therefore,
despite the relative accuracy and dimensional stability of elastomeric
materials and their ease of use and convenience, their use in these cir-
cumstances is likely to result in an inaccurate mounting and subsequent
478 R.S. Squier / Dent Clin N Am 48 (2004) 471486

diculty in delivering the nal restoration(s) because of no occlusion or

a resulting heavy occlusion.

The use of prosthesis frameworks

For a variety of clinical conditions, a xed metal framework or a metal
framework for a removable partial denture can be used to support an
interocclusal record. The benet of using a metal framework to support an
interocclusal record is that the metal framework usually has more stability
and retention than a record base-occlusion rim. For instance, when one is
remounting casts after the metal try-in of xed restorations, the recording
material may be added directly to the metal framework [5]. The framework
may carry an elastic material to make a segmental existing tripod record or
a rigid material to contact the opposing teeth and make a created tripod
record. When a practitioner requests a metal framework to be returned for
try-in before porcelain application, not only should the metal be examined
for t, but also the opportunity should be taken to verify the accuracy of the
articulation of the working casts. The added time in verifying the articu-
lation could save considerable time at the insertion appointment.
When fabricating xed restorations in combination with a removable
partial denture (RPD), jaw relation records are often dicult due to the
diculty in achieving good stability of a record base and occlusion rim. The
tted framework of the RPD can be used as a record base, and the occlusion
rim can be formed directly into the meshwork areas [4,5] (Fig. 6). The
framework adds retention and stability for an interocclusal record, thereby
increasing its accuracy.

Articulator choice
When fabricating xed and removable prostheses, the use of an ad-
justable articulator usually reduces the amount of intraoral adjustment

Fig. 6. A tted RPD framework used as a record base and the occlusion rim formed directly
into the meshwork areas. The framework adds retention and stability for the interocclusal
records, thereby increasing its accuracy.
 R.S. Squier / Dent Clin N Am 48 (2004) 471486 479

needed. A more anatomically sized articulator, such as a programmed

adjustable or a semiadjustable articulator, better reproduces the mandibular
border movements compared with a simple hinge articulator. An articulator
that is more true to human size allows the restoration to be adjusted by the
technician to a greater degree and to a closer approximation of the patients
intraoral situation. A full-size adjustable or semi-adjustable articulator is an
excellent investment for the dentist who does a substantial amount of crown
and bridge.

Purpose of a facebow
The purpose of a facebow transfer is to orient the maxillary cast to
the transverse axis of the articulator. Its use is limited to adjustable and
semi-adjustable articulators. Facebows are not necessary if there will be no
change in the VDO. However, if any alteration of the VDO is planned, as in
a full-mouth rehabilitation, a facebow (and a full-sized articulator) should
be used. Another positive aspect of using a facebow is that it makes it easier
to mount a maxillary cast to a full-sized articulator.

Avoiding errors and inaccuracies

Inaccuracies in jaw relations can be caused by a number of factors besides
a poor interocclusal record. Errors can be introduced anywhere from im-
pressions to cast accuracy to problems with the articulation of the casts.
These areas are often overlooked and are as important for overall accuracy
as the interocclusal record.
All impression materials, all dental stones or plasters, and all inter-
occlusal materials have inherent inaccuracies: they shrink or expand. Learn-
ing how to minimize these inaccuracies improves the end product and results
in a more successful outcome to the practitioner and to the patient.
Accuracy of dental casts and their subsequent successful articulation are
essential when trying to maximize quality while minimizing treatment time
with a patient. The following pearls elucidate common problem areas and
discuss how to handle them.

Movement during setting of material

Movement of the impression tray during the setting time of the im-
pression material leads to inaccuracy. Minor movement while making an
impression for study casts may not be too harmful in the overall scheme
of treatment; however, the same movement for a nal impression is
detrimental to the fabrication of a xed restoration. Once the tray with
impression material is seated in the mouth, it is essential that any movement
480 R.S. Squier / Dent Clin N Am 48 (2004) 471486

by the operator or the patient be prevented. An impression tray should

never be left in a patients mouth without being stabilized by the practitioner
or dental assistant. Additionally, a patient should not be allowed to close
into a full-arch impression tray at any time; the practitioners or dental
assistants ngers should prevent this from occurring.

Impression material dislodged from the impression tray

Dislodged impression material occurs most frequently with alginate
impression material. If a plastic stock tray is used and if the impression tray
is not adequately painted with adhesive, the alginate has to rely solely on the
perforations in the tray and may separate from the tray as the impression is
removed from the mouth. This may happen with a metal stock tray as well
because adhesive is generally not used in these trays for added security. Once
distorted, the alginate cannot be pushed back into place; a new impression
has to be made. This separation of alginate from the impression tray may be
overlooked as a non-essential factor or may go unnoticed. Separation of the
impression material from the tray is a common cause of inaccurate casts.
Although less likely than with alginate, the same separation of impression
material from an impression tray may occur with elastomeric nal impres-
sion materials. After removing any impression from a patients mouth,
the overall adherence of the impression material to the tray should be
examined. This step reduces cast inaccuracies and the resultant errors in
the fabrication of a restoration.

Laying alginate on tabletop with long extensions

Alginate impression material that is unsupported by an impression tray is
under stress. Using an impression tray that does not adequately match
a patients arch size runs the risk that a large portion of the alginate will
be unsupported and therefore may become distorted. In addition, after
an alginate impression is made, the practitioner usually places it on
a countertop with the overextended alginate in direct contact with the at
surface. Any direct pressure on the unsupported alginate distorts the
impression. Ideally, an impression as discussed would be made and then
disinfected and poured in dental stone while being held in a holding tree
so the impression tray hangs from its handle rather than rests on the
countertop (Fig. 7).

Pouring casts on time

Certain impression materials, such as reversible and irreversible hydro-
colloids (alginate), must be poured promptly after making an impression, or
rapid distortion occurs. After disinfection of either impression material,
a cast should be poured immediately. Failure to do so causes loss of water
 R.S. Squier / Dent Clin N Am 48 (2004) 471486 481

Fig. 7. (A) An overextended alginate should never be placed directly into contact with a at
surface. This causes distortion of the unsupported alginate material and results in an inaccurate
cast. (B) Ideally, an alginate impression with distal extensions should be placed in a holding
tree where the impression hangs from its handle rather than rests on a countertop during
disinfection and pouring in dental stone.

from the impression material. This loss of water distorts an impression and
produces inaccuracies in the cast that aect the working dies for a xed
restoration or the articulation of the casts. It is important when using
any impression material to read the manufacturers recommendations for
the maximum time allowable before pouring the impression to reduce
inaccuracies.

Casts have major blebs on occlusal surfaces aecting articulation

The majority of dental casts have blebs on the occlusal surfaces of the
teeth. If they are large enough and go unnoticed, the articulation of casts
can be signicantly altered, leading to a false mounting of the casts. The
occlusal surfaces of the teeth on the casts should be free of these blebs, which
interfere with the proper relationship of the casts. After impressions are
poured and before mounting the casts, the occlusal surfaces should be
examined and freed of any major blebs that would interfere with an accurate
intercuspation of the teeth.
482 R.S. Squier / Dent Clin N Am 48 (2004) 471486

Hand articulate whenever possible

In a fully dentate patient with good maximum intercuspation and a widely
spaced tripod, the most accurate method of relating casts is by hand
articulation. The use of an interocclusal record in such a situation can result
in (1) the inability to accurately mount the casts due to the thickness of the
recording materials (see Figs. 1 and 2), (2) wasted time, and (3) wasted
material and, therefore, money.

Heels of the casts touch

Casts that are improperly trimmed may have interferences that make
mounting dicult. One common site for this is the heel of the casts. Casts
that extend too far posteriorly behind the retromolar pad and the maxillary
tuberosity often interfere when the casts are mounted. Sometimes this goes
unnoticed, especially when these extensions are preceded by edentulous
areas. Touching heels prevents interocclusal records from tting accurately
to the casts and results in inaccurate mountings.

Mush bites
When a patient is asked to bite into a large amount of material, it is often
impossible to determine whether their teeth are coming into contact with
one another because the amount of material obscures the practitioner from
visualizing good tooth contact (Figs. 8 and 9). In addition, when applying
the material for this type of record, if part of it sets while the rest of it is
dead soft, the accuracy is compromised. In general, interocclusal records
should be made with a minimum of material between the teeth or applied to
a record base.

Mouth open during triple tray impression

When a patient bites into a large amount of impression material, the teeth
frequently do not make contact. Triple tray impressions are notorious for
this because it is often dicult to visualize tooth contact with the impression
material in a patients mouth (Fig. 10). It may not be noticed until the dental
laboratory pours the impression and mounts the casts that the patient had
not closed completely. When using triple trays, it is essential that the
practitioner runs the patient through the motion and discusses with them
what it should feel like when they close down through the material. One
should not assume that the patient would close all the way through the
material without proper instruction. In addition, the teeth on the opposite
side of the arch to be impressed should be examined, and contacts should
be visualized between the teeth before making the impression. When the
impression is seated in the mouth and the patient closes, the practitioner
should re-examine these same tooth contacts to ensure that they are the
 R.S. Squier / Dent Clin N Am 48 (2004) 471486 483

Fig. 8. (A) This patient was asked to bite into a large amount of putty material as an
interocclusal record. (B) In the laboratory, it was clear from the marks on the adjacent teeth
that the mush bite prevented the patient from fully closing. In addition, there was insucient
occlusal reduction of the tooth preparations. In this situation where the restorations serve as the
third leg of the tripod, a more rigid interocclusal material, such as resin, would be preferred over
an elastomeric impression material due to increased accuracy.

same. If not, there is likelihood that the patient did not close correctly or
fully through the impression material.

Casts moved during articulation

When mounting dental casts onto an articulator, it is essential that the
maxillary and mandibular casts be joined in such a way as to avoid any
potential movement. Even in patients with good intercuspation, if the casts
are not held immobile during mounting, any slight movement translates into
some amount of discrepancy. There are multiple methods of mounting casts.
The best method is the use of a combination of rigid sticks and compound
or sticky wax (Fig. 11). The casts must be dry when using these materials to
avoid any movement. Sticky wax placed directly onto the opposing teeth can
also be used; however, when the sticky wax is removed, the teeth often break
o the cast or are severely broken.
484 R.S. Squier / Dent Clin N Am 48 (2004) 471486

Fig. 9. A similar patient situation to Fig. 8 illustrating the same principles.

Using a second pour of your nal impression

Most practitioners send their nal xed impressions to a dental labo-
ratory to be poured. The laboratory does the cast and die work and re-
turns the restoration to the dentist. An important and often overlooked
service that the laboratory can provide is to pour a second unsectioned cast
of the nal impression. This second pour may be more accurate than the
cast with sawed dies for adjusting the occlusion and the contacts. The dies of
a working cast have some amount of mobility due to the pindexing system,
a fact that makes getting perfect contacts dicult. In addition, the adjacent
and opposing teeth on a stone cast invariably are abraded during restoration
fabrication. Using a solid, unsectioned second pour allows the dental
technician to examine the proximal and occlusal contacts achieved on the
working casts and to improve these contacts when decient before returning

Fig. 10. A triple tray impression can be problematic because it is often dicult to visualize
tooth contacts with a large amount of impression material in a patients mouth. In this case, it is
clear that the teeth on the opposite side of the arch are not contacting. If the tooth contacts are
not the same as without the impression in the mouth, there is likelihood that the patient did not
close correctly or fully through the impression material, and the impression should be remade.
 R.S. Squier / Dent Clin N Am 48 (2004) 471486 485

Fig. 11. The best method of mounting maxillary and mandibular casts on an articulator to
avoid any potential movement is to join the dry casts with a combination of rigid sticks and
compound. Before joining the two casts, the heels of the casts were checked for any interference.
Note that the maxillary cast has already been mounted using a facebow, and the articulator has
been inverted to mount the mandibular cast after the two have been joined rigidly.

the restoration to the dentist for delivery. This step can reduce the number
of returns of the restorations to the laboratory for the addition of proximal
and occlusal contacts and can make delivery of nal restorations easier and
more pleasurable.

Materials for interocclusal records

The most commonly used materials for interocclusal records are the fast-
setting elastomeric interocclusal registration materials or wax. Elastomeric
materials such as polyvinylsiloxane are well suited for making interocclusal
records where only horizontal stability is needed. However, their accuracy
can be compromised if they are not properly trimmed. These records should
be carefully trimmed to remove all areas of the record that contact soft tissues
and the axial surfaces of the teeth. This is done to minimize the areas where
the casts and the record touch, allowing the practitioner to visualize how the
casts seat into the record and ensuring that the record provides only the
horizontal support with the contacting teeth providing the vertical support.
To assure accuracy, only cusp tips of opposing teeth should be registered in
the material used. Excess material that ows on the axial surfaces of natural
teeth invites error when repositioning the working casts in the registration.
The following adage says it well: In most instances, a minimal amount of
registration material will give a maximum amount of accuracy.

Summary
This article discusses and reviews general principles of jaw relation
records, including the purpose of a jaw relation record and the concept of
486 R.S. Squier / Dent Clin N Am 48 (2004) 471486

a tripod of vertical support with adequate horizontal stability to allow

opposing dental casts to be mounted accurately on an articulator. The use of
the MIP position for the vast majority of patients is favored when the goal
of restorative treatment is to maintain a patients pretreatment intercuspa-
tion and vertical VDO. In addition, articulator choice, purpose of a facebow,
and materials for jaw relation records are discussed. Common errors in
making impressions, pouring impressions, mounting casts, and making
interocclusal records are elucidated, providing the practitioner important
information with which to avoid inaccuracies that may lead to additional
time spent making intraoral occlusal adjustments at the insertion of xed
restorations.

Acknowledgments
The author thanks Dr. Martin Freilich for his expertise and guidance in
the writing of this article.

References
[1] Freilich MA, Altieri JV, Wahle JJ. Principles for selecting interocclusal records for
articulation of dentate and partially dentate casts. J Prosthet Dent 1992;68:3617.
[2] Balthazar-Hart Y, Sandrik JL, Malone WFP, Mazur B, Hart T. Accuracy and dimensional
stability of four interocclusal recording materials. J Prosthet Dent 1981;45:58691.
[3] Fattore LD, Malone WFP, Sandrik JL, Mazur B, Hart T. Clincial evaluation of the
accuracy of interocclusal recording materials. J Prosthet Dent 1984;51:1527.
[4] McGivney GP, Castleberry DJ. McCrackens removable partial denture prosthodontics.
8th ed. St. Louis: CV Mosby; 1989.
[5] Warren K, Capp N. A review of principles and techniques for making interocclusal records
for mounting working casts. Int J Prosthodont 1990;3:3418.