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A Customized Method for
Palatal Crib Fabrication
DANIELA FEU, MSc, PHD
LUCIANE MACEDO DE MENEZES, MSc, PHD
ANA PAULA ABDO QUINTÃO
CATIA CARDOSO ABDO QUINTÃO, MSc, PHD
T
he etiology of anterior open bite involves a
multitude of factors: unfavorable growth, heredity, pacifier and digital habits, retained infantile
swallowing habits, enlarged lymphatic tissue,
tongue function, and tongue posture.1 The complexity of these challenging malocclusions often
requires a combination of behavior modification
and orthodontic and orthopedic therapies.2,3
Unfortunately, correction of the anterior open
bite is only part of the challenge.4,5 Lopez-Gavito
and colleagues reported that more than 35% of
anterior-open-bite patients treated with conventional orthodontic appliances relapsed by more
than 3mm within 10 years of treatment.6 Smithpeter
and Covell found a mean overbite relapse of 3.4mm,
with a range of 1-7mm.4 Denison and colleagues
reported that surgically treated anterior open bites
also exhibited significant relapse.7 In a metaanalysis, Greenlee and colleagues found re­­lapse of
both surgical and nonsurgical treatment of anterior open bites after about three years.5
One possible explanation for these findings
is that the role of tongue function and posture may
have been overlooked.8 Most authors agree that
secondary dysfunctions—especially poor tongue
posture at rest—can persist after the correction of
abnormal function.9-11 The gentle but continuous
pressure exerted by the tongue against the teeth
can have a significant effect. Modification of tongue
behavior is therefore likely to improve the stability of corrected anterior open bites.
Tongue cribs induce a change in the resting
position of the tongue, thus allowing tooth eruption
and closure of an anterior open bite. Some authors
find the crib appliance to be successful in modify-
406
ing tongue behavior,8,12-14 but others disagree.2,3,15
This controversy could be explained by individual
variation in the adaptive capacity of the tongue,2,3
the crib design, or the duration of crib use.8 A fixed
appliance reportedly produces more favorable
results,14,16 but the crib’s dimensions and adaptation
may also affect the tongue response.17-19
This article describes a simple method of
fabricating a fixed palatal crib using a customized
template to facilitate laboratory procedures, standardize parameters for crib construction, and im­­
prove the fitting of each patient with an effective
design.
Case Report
A 6½-year-old female in the mixed dentition
presented with a severe anterior open bite (Fig. 1).
Her history included a tonsillectomy, prolonged
pacifier use, and abnormal tongue posture. Clini­
cally, she displayed a convex profile, an acute nasolabial angle, contraction of the perioral muscles on
lip sealing, and a reverse smile arc with inadequate
exposure of the maxillary incisors. She had a Class
I occlusion with no overjet, a 4.2mm anterior open
bite, a tendency toward posterior crossbite, and a
2mm deviation of the lower midline to the left.
Evaluation of oral function showed a tongue
thrust when swallowing and difficulty in pronouncing some phonemes. At the time of the consultation, the patient had quit pacifier use and had no
remaining sucking habits, suggesting that the an­­
terior open bite was related to or maintained by
her abnormal tongue posture. Horizontal posturing
of the tongue was indicated by the patient’s normal
© 2013 JCO, Inc.
JCO/JULY 2013
Dr. Feu
Dr. Menezes
Ms. Ana Quintão
Dr. Catia Quintão
Dr. Feu is an orthodontic specialist, Ms. Ana Quintão is a student, and Dr. Catia Quintão is an Adjunct Professor, Department of Orthodontics, Rio
de Janeiro State University, Brazil. Dr. Menezes is an Adjunct Professor, Department of Orthodontics, Pontifical Catholic University of Rio Grande
do Sul, Brazil. Contact Dr. Feu at R. da Grécia 85/1101, Barro Vermelho, Vitória, ES 29057-660, Brazil; e-mail: [email protected].
lower-arch level compared with a protrusive upperincisor position above the occlusal level.19 There­
fore, tongue-retaining treatment with a fixed palatal
crib was prescribed in this case.
Study casts were taken in maximum intercuspation, and a wax template was designed to
indicate the crib’s vertical and transverse dimensions while avoiding excessive occlusal interfer-
ence and providing adequate coverage of the
lingual dental surfaces. Since a palatal crib ameliorates an anterior open bite by preventing the
tongue from resting on the teeth, it must also ex­­
tend far enough inferiorly to keep the tongue from
positioning itself below the crib.18 Our crib extended to the lingual gingival margins of the lower
incisors and transversely from canine to canine to
Fig. 1 6½-year-old female patient with 4.2mm anterior open bite, posterior crossbite tendency, and history
of pacifier use and abnormal tongue posture before treatment. Horizontal tongue posturing was suggested
by normal lower-arch level and protrusive, raised position of upper incisors.
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A Customized Method for Palatal Crib Fabrication
cover the farthest possible anterior projection of
the tongue and thus prevent further accommodation of the abnormal tongue posture (Fig. 2).
Using the template as a guide, a crib was bent
from .036" stainless steel wire (Fig. 3A), adapted
to the plaster cast (Fig. 3B), and welded to the
first-molar bands and to palatal and transpalatal
arches to reinforce the crib structure and prevent
forward-rocking movements (Fig. 3C,D).
Eight months later, due to the interruption of
improper tongue posturing, the patient’s anterior
open bite had spontaneously corrected (Fig. 4A). The
crib was removed after another four months (Fig.
4B). Cephalometric superimposition confirmed
spontaneous extrusion of the incisors (Fig. 4C).
The results were stable for five years (Fig. 5),
after which the patient underwent seven months of
orthodontic treatment to level and align the arches.
Ten years after crib removal, the anterior open bite
was still normal (Fig. 6).
Discussion
Fink suggested that the effectiveness of crib
therapy is derived not from a dynamic restraint of
the tongue, but rather from a redirection of the
tongue’s resting position.20 Therefore, both the crib
design and the duration of treatment are important
considerations.8,18 Subtelny and Sakuda reported
unsuccessful redirection of tongue position in
open-bite treatment when a crib was worn for less
than six months.3 There is now a consensus that
these devices should be fixed, with the objective
of retraining the dentition in normal function until
spontaneous favorable movement is attained.14,21
Taslan and colleagues found that resting tongue
pressures remained significantly lower than initial
values at the 12th month of crib wear, suggesting
that the tongue adapts to the new position created
by the appliance.22 Our patient used the crib for 12
months—long enough to produce definitive behav-
Fig. 2 Wax template formed for optimal size and shape of palatal crib, extending from upper- to lowerincisor gingival margins and transversely from canine to canine.
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Feu, Menezes, Quintão, and Quintão
ioral changes.13,22
Since the vertical height and transverse length
of a palatal crib have yet to be standardized, the
inevitable variations in fabrication may be a reason
for the inconsistent results found in the literature
and in daily practice.23,24 A template, as shown here,
could be helpful in obtaining more reliable results.
In our experience, the following parameters should
be observed:
• The appliance should extend to the lingual gin-
A
B
C
D
Fig. 3 A. Crib constructed from .036" stainless steel wire, using wax template as guide. B. Crib formed
to plaster cast to verify optimal fit. C. Finished appliance welded to molar bands and to palatal and trans­
palatal arches. D. Palatal crib in place.
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A Customized Method for Palatal Crib Fabrication
A
B
Fig. 4 A. Patient after eight months of crib use. B. Crib removed after
12 months of treatment. C. Superimposition of tracings before and
after palatal-crib treatment.
C
gival margin of the lower incisors in the posterior
view of the occluded casts.
• The appliance should extend transversely from
the upper left canine to the upper right canine.
• A wax template formed to the occluded study
casts in maximum intercuspation will facilitate the
laboratory fabrication of an appropriate design for
each patient. This enables the clinician to produce
an effective tongue crib that is easily adapted in
the mouth, requiring less chairtime at delivery.
Conclusion
Abnormal tongue posture in the presence of
anterior open bite must be analyzed and addressed
with appropriate appliances. The standardized
fabrication method presented in this article enables
clinicians to produce cribs that are optimally de­­
signed and will thus reduce the chairtime required
for adjustments. Long-term evaluation of the performance of standardized cribs and the stability of
their results is recommended.
(continued on p. 412)
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Feu, Menezes, Quintão, and Quintão
Fig. 5 Patient five years after crib removal.
Fig. 6 Patient 10 years after crib removal, following orthodontic treatment to level and align arches.
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