It has been accepted for the past many decades that an anatomically related anterior reference point is required during a face-bow transfer. Many anterior reference points have been advocated by different researchers. This paper explores several articles including systematic reviews and clinical trials regarding different concepts of face bow and came to the conclusion that the literature search failed to draw up evidence from controlled trials that there is any benefit from locating an anatomically related anterior reference point during face bow transfer in complete denture. And face bow transfer itself is the waste of time and manpower in complete denture construction.
Key words: Facebow, Anterior reference point, plane of reference
In prosthodontics, while we attempt to restore or
replace missing teeth, it becomes imperative to
mount patients maxillomandibular relation on
an articulator with maxillary and mandibular
casts, oriented to the hinge axis, for laboratory
procedures. Facebow is a caliper-like instrument used to record the spatial relationship of the
maxillary arch to some anatomic reference point
or points and then transfer this relationship to an
articulator.1
This requires the use of two posterior
points and an anterior point of reference for
orienting a maxillary cast to an articulator.2
Maxilla is a part of the cranium and is a fixed
entity. When the teeth of both jaws come in contact,
maxilla becomes related to the mandible so that
entire craniomaxillary complex is articulated with a
moving bone, which is the mandible. The opening
movement to bring the jaw from occlusal to rest
position is almost a pure hinge movement. Here
the mandible moves in an arc of a circle with a
definite radius from the temporomandibular joint.
This path of the condyle is determined by the
curvature of the condylar head and the curvature
of glenoid fossa.3
Since the radius is not constant
for all the patients, it has to be determined for
every individual patient. Similarly the relationship
of upper jaw to the lower jaw and the anatomy of
maxilla and the temperomandibular joint varies
from one individual to the other. Thus, recording
of the orientation jaw relationship is considered
to be very important, which is done with the help
of facebow record.4
An anterior reference point is a physical requirement for orienting casts in the three dimensional space
in an articulator.5
Many researchers advocated that
improper positioning of the casts in an articulator
may result in an inadequate restoration with an
undesirable appearance and cause damage to
the supporting structures.6
It is commonly seen in
general practice, that we avoid using a facebow
transfer with third point of reference and mount
the cast in average values especially in complete
denture fabrication.7
Zarb Bolender stated that “The success of dental
treatment involves many factors and the use of
facebow is not an essential one.”8
So we conducted
a literature review to find the significance of
facebow transfer in complete denture fabrication.
Logan considered the use of face bow
indispensable. He said that facebow is very
important in obtaining maxillary orientation.9
But
Craddock and Symmons considered it as futile
exercise. They utilized both maxillomandibular
relation and found that face bow transfer was just
waste of time and money and discomfort for the
patient. They said it was very time consuming and
tiring for the dentist also.10 Later Stansbery said
that it is only a technique to position the records
and told that use of face bow was useless.11
In 1969 a 20 year follow up study was conducted
by Hickey et al in Kentucky College of Dentistry
in which they utilized 64 patients. They divided
the patients into two groups of 32 each. One
group which received complete denture with
facebow transfer and the other without facebow transfer. They compared the difference between
both the groups in all aspects including patient
satisfaction and acceptance. They found no
difference in retention, stability, ridge resorption
or even centric occlusion.12 Weinberg in another
study concluded that as the plane of occlusion
is elevated the condylar angle decreases, and
the vice versa. In this manner we can change the
orientation of maxillary and mandibular cast
and hence facebow is not essential. Only small
degree of error at the balancing cusp incline was
seen which was negligible.13 Ercoli et al supported
Weinberg stating that any change in the inclination
of maxillary cast on the sagittal plane will have no
effect as far as inclination of the condylar path is
also modified for the same angle and that reference
planes were not needed for correct mounting of
stone casts.14 Bailey and Nowlin studied on two
different 3rd reference points, the middle groove
on Incisal guide pin and Orbitale. They concluded
that both gave comparable results in positioning
the maxilla and obtaining proper occlusion.15
A change of height in the mounting of the casts
when a facebow transfer is used will not alter the
relation of the casts to the condylar inclination.16 In
1968, Gonzalez and Kingery used cephalometric
radiographs of denture patients to evaluate
the planes of reference used by dentists when
transferring the maxillary cast to the articulator.
They found that the relationships of the planes
of reference on the patient were not maintained
once transferred to the articulator and that the
average perpendicular distance from the axis
to Frankfort Horizontal plane was 7.1mm.17 In
1985, Zuckerman discussed the downfalls of
using a facebow to articulate maxillary casts
when the patient has an asymmetrical orientation
in the horizontal and vertical plane of orientation
relative to their vertical cranial posture. This can
lead to misinterpretations by the lab technician
leading to skewed midlines and cants in the
occlusal plane. He goes on to say that, “Until an
instrument that can adjust to all the anatomic hinge axis asymmetries becomes available, it is
more appropriate to use a method other than the
facebow to record the orientation of the maxillary
cast,”18. Nascimento et al said that balanced
occlusion can be achieved even without facebow
transfer. They observed better patient satisfaction
and greater number of occlusal contacts in centric
relation and left lateral movements without using
facebow.19 Study by Kawai et al got similar results
when they conducted a randomized control
trail with 122 patients. They randomly divided
the patients into two groups, one group which
received complete denture with facebow transfer
and another without facebow transfer. They found
no significant difference in patient satisfaction
or quality of the denture produced by both the
methods.20 They also concluded that the method
without facebow transfer reduced the laboratory
cost and clinician’s time.21
Hartmann R et al and Pitchford found an
alternative method to avoid the use of facebow.
Pitchford found that in the esthetic reference plane
(ERP), the orbitale was 18.5 mm higher than the
axis and 11.4 mm higher than the porion. Soto
duplicate the vertical position of the maxillary cast
in esthetic reference plane, the incisal edges of
maxillary incisor teeth should be 36 mm below the
condylar plane of the articulator.22 Hartmann R et
al compared both face bow and jig method They
concluded that the universal 15 degree mounting
jig showed statistically equal results to that of
face-bow in complete denture patients.23
Recently Kumar and D’souza did a clinical trial
using 20 patients who had normal ridge and
class I relation. All of them received two sets of
denture, one set made with face bow transfer and
the other without face bow transfer. They found
that there was no significant change between both
the dentures and patient were more comfortable with the denture which was made without face
bow transfer.24 In a pilot study done by Turp CJ
et al to evaluate whether an arbitrary face bow
registration and transfer provides significant
advantages in fabrication of complete denture and
occlusal appliance, they could find no clinically
relevant benefits with the use of face bow in the
fabrication of complete denture.25 Keith Yohn got
similar results showing no evidence to suggest that
using a face bow transfer improved the results in
terms of patient’s speech, the fit and comfort of
the prostheses, ridge morphology,facial contours,
the color of the teeth and denture bases,and the
psychological aspects the arrangement of the
artificial teeth, chewing efficiency, and stability,
of complete denture patients.26
One of the systematic review which studied
randomized control trials alone, found that there
is no clinically significant difference, by using
and without using face bow for complete denture
fabrication.27 Four other systematic reviews also
got similar results. They evaluated the influence of
face bow transfer and occlusal concept on general
satisfaction, comfort, ability to speak, stability,
esthetics, ease of cleaning, and ability to chew
and came to a conclusion that chewing ability
was rated more favourable for complete denture
without face bow transfer.28, 29, 30, 31 Recent systematic
review by Khan et al found that the face bow
fails to demonstrate its utility in the fabrication of
complete dentures and occlusal splints. They also
said that thus, there is no evidence to continue its
use in the dental practice and teaching in terms
of complete denture fabrication.32
“But its use in fixed prosthesis was supported
in systematic reviews and need to be studied
further before making a conclusion regarding the
application in fixed prosthodontics.”
It is the duty of the prosthodontist to give good
quality dentures for the patients within the
available constraints of time and manpower. There
is no evidence from controlled trials, of any benefit
from locating an anatomically related anterior
reference point during face-bow transfer. And
also there is no evidence showing that face bow
transfer will help us to provide such a denture for
the patient. Hanau has stated that “By Realeff at
various stages of complete denture construction
we can achieve better stable dentures.”The
authors suggest to study the possible influence
of Realeff in making facebow transfer insignificant
in complete denture..33 So it is high time to think
whether facebow transfer is necessary in complete
denture prosthodontics.