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©2013 JCO, Inc. May not be distributed without permission. www.jco-online.com 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. VOLUME XLVII NUMBER 7 407 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. 408 JCO/JULY 2013 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. VOLUME XLVII NUMBER 7 409 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) 410 JCO/JULY 2013 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. VOLUME XLVII NUMBER 7 411 A Customized Method for Palatal Crib Fabrication REFERENCES 1. Almeida, R.R. and Ursi, W.J.: Anterior open bite: Etiology and treatment, Oral Health 80:27-31, 1990. 2. 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Huang, G.J.; Justus, R.; Kennedy, D.B.; and Kokich, V.G.: Stability of anterior open bite treated with crib therapy, Angle Orthod. 60:17-24, 1990. 9. Shapiro, P.A.: Stability of open bite treatment, Am. J. Orthod. 121:566-568, 2002. 10. Miller, H.: The early treatment of anterior open bite, Int. J. Orthod. 7:5-14, 1969. 11. Proffit, W.R.: Equilibrium theory revisited: Factors influencing position of the teeth, Angle Orthod. 48:175-186, 1978. 12. Haryett, R.D.; Hansen, F.C.; and Davidson, P.O.: Chronic thumb-sucking. A second report on treatment and its psychological effects, Am. J. Orthod. 57:164-178, 1970. 13. Justus, R.: Treatment of anterior open bite: A cephalometric and clinical study, Rev. Asoc. Dent. Mex. 33:17-40, 1976. 14. Cozza, P.; Mucedero, M.; Baccetti, T.; and Franchi, L.: Com 412 parison of two early treatment protocols for open bite malocclusions, Am. J. Orthod. 132:743-747, 2005. 15. Cooper, J.S.: A comparison of myofunctional therapy and crib appliance effects with a maturational guidance control group (abstr.), Am. J. Orthod. 72:333-334, 1977. 16. Giuntini, V.; Franchi, L.; Baccetti, T.; Mucedero, M.; and Cozza, P.: Dentoskeletal changes associated with fixed and removable appliances with a crib in open-bite patients in mixed dentition, Am. J. Orthod. 133:77-80, 2008. 17. Al-Emran, S.: A modified palatal crib appliance for children with predetermined thumb-sucking habit: Case report, Saudi Dent. J. 20:31-35, 2008. 18. Subtelny, J.D.: Examination of current philosophies associated with swallowing behavior, Am. J. Orthod. 51:161-182, 1965. 19. Artese, A.; Drummond, S.; Nascimento, J.M.; and Artese, F.: Criteria for diagnosing and treating anterior open bite with stability, Dent. Press J. Orthod. 16:136-161, 2011. 20. Fink, F.S.: Resting position of tongue important, Angle Orthod. 60:244, 1990. 21. Meyer-Marcotty, P.; Hartmann, J.; and Stellzig-Eisenhauer, A.: Dentoalveolar open bite treatment with spur appliances, J. Orofac. Orthop. 68:510-521, 2007. 22. Taslan, S.; Biren, S.; and Ceylanoglu, C.: Tongue pressure changes before, during and after crib appliance therapy, Angle Orthod. 80:533-539, 2010. 23. Lentini-Oliveira, D.; Carvalho, F.R.; Qingsong, Y.; Junjie, L.; Saconato, H.; Machado, M.A.; Prado, L.B.; and Prado, G.F.: Orthodontic and orthopedic treatment for anterior open bite in children, Cochrane Database Syst. Rev. 2007, No. 2, Art. CD005515. 24. Sayin, M.O.; Akin, E.; Karacay, S.; and Bulakbasi, N.: Initial effects of the tongue crib on tongue movements during deglutition: A Cine-Magnetic resonance imaging study, Angle Orthod. 76:400-405, 2006. JCO/JULY 2013