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 Table of Contents  
Year : 2018  |  Volume : 5  |  Issue : 1  |  Page : 32-39

Maxillary protraction by reverse headgear treatment in patients with unilateral cleft lip and palate: A cephalometric evaluation

1 Department of Dentistry, Government Medical College and Hospital, Chandigarh, India
2 Oral Health Sciences Centre, Postgraduate Institute of Medical Education and Research, Chandigarh, India
3 Graduate Orthodontic Program, Faculty of Dentistry, University of Toronto; Burlington Growth Centre, Faculty of Dentistry; Department of Dentistry, The Hospital for Sick Children, Toronto, Ontario, Canada

Date of Web Publication8-Feb-2018

Correspondence Address:
Dr. Sapna Singla
Department of Dentistry, Government Medical College and Hospital, Sector-32, Chandigarh - 160 033
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Source of Support: None, Conflict of Interest: None

DOI: 10.4103/jclpca.jclpca_36_17

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Objective: This investigation was undertaken with the primary aim of evaluating the effects of reverse headgear therapy in patients with unilateral cleft lip and palate (UCLP) using lateral cephalograms and to compare the results of the reverse headgear treatment in these patients with other patients with UCLP who did not receive any orthopedic/orthodontic treatment. Materials and Methods: The treated group comprised 17 patients (13 male, 4 female; mean age 9.28 ± 2.78 years) with repaired complete UCLP and untreated group consisted of 5 subjects (4 male, 1 female; mean age 8.25 ± 2.25 years) with repaired complete UCLP. All patients in treated group received maxillary protraction with a Delaire type reverse headgear along with a customized intraoral splint worn for 16–18 h daily with force in the range of 420–480 g. Subjects in the untreated group did not receive any orthopedic/orthodontic treatment. Average treatment/observation period was 11.62 months for the treated and 12.40 months for the untreated group. Changes were evaluated at the end of the treatment and observation period by comparing pre- and post-lateral cephalograms. Results: Treatment effects of reverse headgear therapy were significant for anterior positioning of maxilla, clockwise rotation of mandible, proclination of upper incisors, and forward movement of upper molars as shown by cephalometric analysis. The untreated group did not show any significant changes, for the same measurements. Conclusions: Reverse headgear treatment is an effective method of improving the maxillomandibular relationship in patients with UCLP.

Keywords: Cleft lip and palate, maxillary protraction, midfacial retrusion, reverse headgear

How to cite this article:
Singla S, Utreja A, Singh SP, Suri S. Maxillary protraction by reverse headgear treatment in patients with unilateral cleft lip and palate: A cephalometric evaluation. J Cleft Lip Palate Craniofac Anomal 2018;5:32-9

How to cite this URL:
Singla S, Utreja A, Singh SP, Suri S. Maxillary protraction by reverse headgear treatment in patients with unilateral cleft lip and palate: A cephalometric evaluation. J Cleft Lip Palate Craniofac Anomal [serial online] 2018 [cited 2019 Aug 26];5:32-9. Available from: http://www.jclpca.org/text.asp?2018/5/1/32/224901

  Introduction Top

Irrespective of the treatment protocol, a certain number of patients with complete cleft lip and palate (CLP) reveal an unfavorable growth pattern of the craniofacial complex. The general tendency in unilateral clefting is for underdevelopment or posterior positioning of the maxilla relative to anterior cranial base and also shortening of maxillary length relative to the cranial base and maxillary height, relative to the anterior facial height.[1],[2] These factors may lead to a sagittal discrepancy between the upper and lower jaw, with the maxilla in a relatively more retruded position resulting in retrognathic facies and prenormal occlusion, often associated with palatal inclination of the anterior dentoalveolar region.[3]

The physical deformity associated with maxillary hypoplasia contributes to multiple functional deficiencies which include severe malocclusions that result in compromised mastication, speech and also affects nasal and pharyngeal airway patency.[4],[5],[6] Besides, it also contributes to the characteristic unattractiveness of the soft tissue profiles in patients with cleft, which can lead to a great deal of personal, social, and psychological morbidity.[7]

Once retrusion becomes apparent, clinical options include either early orthopedic intervention to normalize the maxillary complex or allowing abnormal facial development to continue, with surgical intervention after the completion of growth.[5]

Early orthopedic correction not only minimizes the amount of later therapy but also leads to early normalization of the sagittal basal relationship resulting in normal function and mastication, hence improving intermaxillary growth, which in turn influences the soft tissue relations and improves overall facial appearance.[6],[7]

Orthopedic protraction has been reported in patients with CLP, but the number of patients in both the studies was small.[8],[9] Moreover, cephalometric studies on patients with CLP treated by protraction are scarce and usually included various types of clefts pooled together.[9],[10],[11] The small and heterogenous samples make the result unmeaningful. Moreover, in some studies, comparisons were made between children with clefts and without clefts, who demonstrate different growth pattern and potentials.[5],[11],[12] Hence, results are somewhat conflicting regarding the therapeutic effects, in terms of extent and areas of improvement with protraction therapy in patients with CLP.

To overcome some of these problems, the present study was conducted to evaluate and analyze the potential of this interceptive orthopedic phase in 17 consecutively treated patients with repaired complete UCLP, having underdevelopment of maxilla and to compare the results with other patients with repaired complete UCLP, who did not receive any orthopedic or orthodontic treatment.

  Materials and Methods Top

Following approval from the institutional review board and obtaining informed consent, seventeen patients comprising the treated group (13 male, 4 female; mean age 9.28 ± 2.78 years) with repaired complete UCLP were subjected to maxillary protraction. All patients had negative overjet and relative midfacial retrusion. None of these patients had received any other pre- and post-surgical orthopedic intervention and no abnormal mandibular displacement was found on clinical examination.

The untreated group consisted of 5 subjects (4 male, 1 female; mean age 8.25 ± 2.25 years) with repaired complete UCLP. The subjects in the untreated group did not receive any orthodontic/orthopedic intervention during the observation period and were followed on a parallel basis with the treated patients during the same period of time. The untreated group was matched with the treated group for age, type of cleft, and skeletal morphology.

Appliance design and treatment procedure

A customized intraoral splint made up of 0.36” stainless steel wire without maxillary expansion was used. The wire framework had inbuilt horizontal hook, in the canine region extending from the main wire on each side buccally [Figure 1]a. This rigid wire framework was covered with self-cure acrylic on both sides, forming a splint with a vertical height within 2–3 mm of total clearance of upper incisors and lower incisors [Figure 1]b and was cemented to the maxillary arch with glass ionomer cement [Figure 1]c. Protraction was carried out with a Delaire type face mask [Figure 2]a. Heavy elastics (0.25 inch, 8 ounces) were attached to hooks extending from the splint near the maxillary canines. The line of the protraction force was downward and forward, at an angle from 15° to 30° to the occlusal plane [Figure 2]b. The force applied ranged between 420 g and 480 g, and patients were instructed to wear the face mask for 16–18 h/day. Treatment progress was monitored clinically through monthly examinations. Pre- and post-treatment records included study models, intra- and extra-oral photographs, and lateral cephalograms [Figure 3]a,[Figure 3]b,[Figure 3]c,[Figure 3]d,[Figure 3]e,[Figure 3]f. The treatment duration was from 11 to 14 months and lasted an average of 11.62 months.
Figure 1: (a) Wire framework. (b) After acrylization. (c) Intraoral view of the splint

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Figure 2: (a) Facemask (Delaire) used for maxillary protraction. (b) Protraction carried out at an angle of 15°–30° to the occlusal plane

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Figure 3: Extra- and intra-oral photographs of a patient treated with reverse headgear. (a-c) Before maxillary protraction. (d-f) After maxillary protraction

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Analysis of lateral cephalometric radiograph

The skeletodental changes that occurred during the treatment period were analyzed by means of two lateral cephalometric radiographs - the first taken at the diagnostic stage before treatment(T1) and second at the time of appliance removal following protraction(T2) in the treated group [Figure 4]a and [Figure 4]b. In the untreated group, the lateral cephalometric radiograhs were taken before and after the observation period. Average treatment/observation period was 11.62 months for the treated and 12.40 months for the untreated group. The radiographs were taken with the mandible in intercuspal position. The same investigator traced the lateral cephalometric radiograph using a 3H pencil on a 0.003-inch acetate film. Measurement points, lines, and definitions used in the lateral cephalometric analysis are presented in [Figure 5] and [Figure 6]. The reproducibility of the measurements was assessed by analyzing the difference between successive measurements of 10 randomly selected lateral cephalograms made 2 weeks apart. Dahlberg formula was used to determine the method error for the variables measured.[13] The combined method error did not exceed 0.220° for angular measurements and 0.158 mm for linear measurements.
Figure 4: Lateral cephalograms of a treated patient showing skeletal and dental changes. (a) before. (b) after protraction

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Figure 5: Landmarks and measurements used in cephalometric analysis. Reference points: S (sella): Midpoint of sella turcica, N (nasion): Most anterior point of frontonasal suture, A point: Most posterior point in the concavity between anterior nasal spine and maxillary alveolar process, B point: Most posterior point in the outer contour of mandibular alveolar process, pm (pterygo-maxillary point): Intersection between the nasal floor and the posterior contour of maxilla, mos (molar superius): Mesial contact point of upper first molar, moi (molar inferius): Mesial contact point of lower first molar. Reference planes: SN: Sella nasion plane (line through S and N), PP: Palatal plane (line through anterior nasal spine and posterior nasal spine), MP: Mandibular plane (line through gnathion anteriorly and gonion posteriorly), NSP: Perpendicular through sella from SN, ILs– upper incisor axis line, ILi–lower incisor axis line. Skeletal and dental angular measurements: 1: Angle SNA, 2: Angle SNB, 3: Angle ANB, 4: Angle SN-PP, 5: Angle SN-MP, 6: Angle ILS–PP, 7: Angle ILi–MP

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Figure 6: Measurements used in cephalometric analysis. Skeletal and dental linear measurements: 8: NSP-A point, 9: NSP-pm, 10: NSP-B point, 11: SN-pm, 12: SN-A point, 13: SN-B point, 14: NSP-mos, 15: NSP-moi

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Statistical methods

Descriptive statistics (means and standard deviations) were calculated from the measurements recorded from cephalometric radiographs at T1 and T2 for both the treated and untreated groups. Differences in dimensions between the treated patients and untreated subjects recorded at T1 and T2 were evaluated using the paired t-test. An exploratory analysis of differences in the changes from T1 to T2 between the treated patients and untreated subjects was also conducted using the two-sample t-test. The levels of significance were determined as P < 0.05, P < 0.01, P < 0.005, and P < 0.001.

  Results Top

Descriptive statistics of the measured variables at T1, and T2 and the differences between T1 and T2 in the treated group are presented in [Table 1]. Paired t-test of the variables revealed statistically significant changes for most cephalometric measurements. Following treatment with a maxillary protraction appliance, SNA increased by 2.35° ± 1.65° (P< 0.001), ANB increased by 4.08° ± 1.75° (P< 0.001), SN-MP increased by 2.47° ± 2.55° (P< 0.001) whereas SNB decreased by 1.61 ± 2.19° (P< 0.01) and SN-PP showed a nonsignificant decrease of 0.14° ± 3.52°, respectively. Angular dental changes showed a significant proclination of upper incisors (ILs-PP) by 8.55° ± 6.89°(P< 0.001) with a nonsignificant change in lower incisor position (ILi-MP).
Table 1: Comparison of pre- and post-treatment measurements in the treated group

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Linear changes in the horizontal direction showed a significant increase in the distance NSP-A and NSP-pm of 3.26 ± 1.67 mm (P< 0.001) and 1.29 ± 1.43 mm (P< 0.005), respectively, whereas there was a significant decrease of NSP-B by 2.40 ± 2.71 mm (P< 0.005). Linear distance in the vertical direction showed a nonsignificant increase of SN-A by 1.50 ± 3.68 mm and SN-pm by 1.50 ± 1.99 mm (P< 0.01) and SN-B showed increase of 3.85 ± 2.88 mm (P< 0.001).

Linear dental changes NSP-mos showed a change 4.35 ± 2.52 mm (P< 0.001) and NSP-moi showed nonsignificant change of −0.38 ± 2.54 mm.

In contrast, in the untreated group SNA decreased by 0.60° ± 1.52°, SNB increased by 0.20° ± 0.84°, ANB decreased by 0.80 ± 0.84°, and SN-MP increased by 1.20° ± 2.59°. Other linear and dental variables also showed nonsignificant changes except angle SN-PP which showed an increase of 3.50° ± 1.66° (P< 0.01) and distance SN-A increased by 4.00 ± 2.12 mm (P< 0.05) [Table 2].
Table 2: Comparison of pre- and post-observations measurements in the untreated group

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The exploratory analysis of differences in the treatment change in the treated patients from the change in the measurements from T1 to T2 in the untreated subjects showed that mean group differences for SNA, ANB, SN-PP, NSP-A, NSP-pm, ILs-PP, and NSP-mos were statistically significant [Table 3].
Table 3: Comparison of changes from T1 to T2 between the treated and untreated group

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  Discussion Top

Reverse headgear treatment has long been advocated to improve the intermaxillary basal relationship and eliminate dysfunction, allowing more harmonious conditions for midfacial growth and development in children with CLP.[7],[11],[14] The present study was conducted with the objective of investigating the changes during the reverse headgear treatment in a group of patients with repaired complete UCLP and also to compare the treatment effects with other patients with repaired complete UCLP, who were not under reverse headgear therapy. The children selected were in the age range of 5–14 years. This age group was selected because protraction appliances have been reported to have maximum effect if the patient is treated early.[11],[14],[15],[16]

The published literature is deficient in studies that describe skeletal and dental effects of reverse headgear treatment in children with repaired complete unilateral cleft lip and palate. Denying treatment of maxillary retrusion in growing children when indicated is ethically unacceptable, which precluded the possibility of having a prospective, randomized, matched control group of untreated subjects for this study. However, there were five North Indian children with repaired complete UCLP having similar skeletal morphology and age (4 male, 1 female; aged 8.25 ± 2.25 years) who had not received maxillary protraction treatment because they lived too far from the institute to be able to attend active treatment visits. These children were under a yearly follow-up examination to monitor their oral health and their craniofacial growth, dental and occlusion development, in order to plan their future treatment. As part of this follow-up, their lateral cephalograms, which had been taken at approximately similar intervals as the treated patients (12.40 ± 2.60 months), were available. In the absence of a matched control group, cephalometric data from this group of children, who had not received reverse headgear treatment, were used to represent control data of children with repaired complete UCLP without maxillary protraction therapy.

The current investigation demonstrated a definite and desirable response to reverse headgear therapy. The mean prognathism of upper jaw as expressed by angle SNA increased significantly during protraction (mean 2.35° ± 1.65o) after11.71 months of protraction therapy, which is more than reported in many other studies.[7],[8],[9],[10],[11] Ishikawa et al. showed an increase of 0.98° in the angle SNA in 26 children (between 5 and 7 years of age) as a result of protraction combined with chincup therapy for a mean duration of 26 months.[17] The reasons for comparatively lesser mean increase compared to our study could be due to certain conditions of protraction such as force duration, magnitude, direction, timing of treatment, sites of appliance, and type of intraoral appliance.[18] Besides, differences in severity of skeletal discrepancy or variation in the cleft itself or variation in scarring after surgical repair, difference in face types, size, and type of the sample could also account for the varying results.[11] However, results of the present study, to a great extent, are comparable with the results of Chen and So [6] who demonstrated a mean increase in SNA by 1.85o in 10 Chinese boys with UCLP (mean age 9.67 years) after 7.8 months of reverse headgear therapy and also with Jia et al.[19] who showed a significant increase in SNA of 1.50o in 18 boys with UCLP (mean age 9.54 + 1.2 years) after 9.2 + 1.6 months of protraction therapy. In comparison, the untreated group showed a reduction of angle SNA by 0.60° which corresponds well with the findings of So.[7]

Several biomechanical studies have shown that the downward vector of protraction decreases the counterclockwise rotation of the maxilla.[20],[21],[22] The angle SN-PP showed a slight mean change of −0.14° ± 3.52o which implied mild counterclockwise rotation of maxilla, in accordance with other studies.[11],[12] The application of force by 15°–30o in a downward–forward direction to the anterior segment of maxillary dental arch may have reduced the counterclockwise rotation.[23] On the other hand, the untreated group showed a significant clockwise rotation of 3.50° ± 1.66° of the palatal plane with respect to anterior cranial base.

A significant clockwise rotation of the mandible as expressed by an increase of angle SN-MP of 2.47° ± 2.55o and reduction of mandibular prognathism (SNB) of −1.61° ± 2.19° was found in the treated group. These results are also well known from various studies reported in the literature that describes maxillary protraction in growing children with clefts.[9],[10],[11],[12],[24] Ishikawa et al. reported 1.27o of posterior rotation of mandible and reduction of mandibular prognathism in 26 UCLP cases who were treated with maxillary protraction combined with chin cup therapy.[17] This effect may have been because of the backward directed force exerted by the chin cup. Fewer studies using maxillary protraction with alternate rapid maxillary expansion and constriction technique also reported similar findings.[25],[26] In comparison, the untreated group showed a slight but nonsignificant clockwise rotation of mandible during the same period. It seems likely that the favorable treatment effects of a facemask depend to some degree on the backward rotation of mandible.

The most clinically significant effect of protraction was related to the correction of sagittal maxillomandibular relationship. The significant mean increase of angle ANB by 4.08° ± 1.75o as compared to decrease by 0.80° ± 0.84° in the untreated group is therefore of great clinical importance. These changes are comparable to Chen and So who found 3.7o and Jia et al. who showed 3.82o increase in angle ANB [6],[19],[24] and greater than many studies.[11],[14],[17] One main reason for such an effect could be increased opening of mandibular plane angle.

In the present study the mean linear forward movement of the posterior border of maxilla was smaller (NSP-pm, 1.29 mm) than that of the anterior part (NSP-A, 3.26 mm) in the treated group. This corresponds well with the results of other studies [5],[11] and is even greater than the figures reported by authors using maxillary protraction with rapid maxillary expansion.[25],[26] Chen and So found a forward movement of point A by 2.05 mm and Ishikawa et al. found a mean forward displacement of maxilla (NSP-A) of 1.42 mm.[6],[17] However, both of these studies did not analyze the movement of posterior border of maxilla (pm) with respect to NSP. The observed maxillary changes are partly in accordance with autopsy studies by Melsen and Melsen who demonstrated increasing complexity of the sutural system around the palatine bone and changes in the palatomaxillary suture with increasing age.[27] The untreated group showed nonsignificant change in the forward movement of maxilla.

The present study showed that upper incisors were proclined by 8.55° ± 6.89° with respect to palatal plane, whereas the lower incisors did not show any significant change in their inclination. This finding corroborates well with that of Tindlund et al.[11],[12],[14] Few studies demonstrated lesser proclination than our study.[9],[10] This degree of proclination was not expected as the design of the splint used is such that it has no direct contact with the incisors and it was thought that this degree of proclination could be due to some measurement error because of short root formation and special conditions of the upper permanent incisors in patients with CLP that made definitions of dental inclination difficult. Furthermore, in some patients at the time of the start of facemask therapy, deciduous incisors were present and at the end of treatment, permanent incisors had erupted. Hence, the actual proclination due to facemask therapy alone may have been masked. The sagittal molar relationships improved a great deal in the treated group because of significant forward movement of the upper molar (NSP-mos). In the untreated group, however, the upper molar (NSP-mos) did not show a significant change. This is greater than many other studies.[6],[11],[14],[19]

  Conclusions Top

  1. The treated group showed a significant protraction of maxilla as evidenced by increase in angle SNA and increase in the linear distance of point A and PM from NSP, whereas the untreated group showed a decrease.
  2. The maxilla did not show any significant rotation after the treatment, but the untreated group showed a significant clockwise rotation of the palatal plane.
  3. There was a clockwise rotation of the mandible with an increase in the mandibular plane angle and reduction of mandibular prognathism in the treated group with no significant change in the untreated group.
  4. The skeletal sagittal maxillomandibular relationship as expressed by angle ANB normalized in the treated group after the protraction therapy.
  5. Maxillary incisor measurements showed a significant proclination at the end of treatment in the treated group.
  6. The maxillary molar showed forward movement in the treated group, contributing to improvement in the molar relationship.

The present study supports the importance of early orthopedic treatment in children with maxillary deficiency due to CLP and emphasizes that maxillary protraction should be included in the cleft management protocol.

Declaration of patient consent

The authors certify that they have obtained all appropriate patient consent forms. In the form the patient(s) has/have given his/her/their consent for his/her/their images and other clinical information to be reported in the journal. The patients understand that their names and initials will not be published and due efforts will be made to conceal their identity, but anonymity cannot be guaranteed.

Financial support and sponsorship


Conflicts of interest

There are no conflicts of interest.

  References Top

Ross RB. The clinical implications of facial growth in cleft lip and palate. Cleft Palate J 1970;7:37-47.  Back to cited text no. 1
Bishara SE, Sierk DL, Huang KS. Longitudinal changes in the dento-facial relationships of unilateral cleft lip and palate subjects. Cleft Palate J 1979;16:391-401.  Back to cited text no. 2
Rygh P, Tindlund R. Orthopedic expansion and protraction of the maxilla in cleft palate patients – A new treatment rationale. Cleft Palate J 1982;19:104-12.  Back to cited text no. 3
Ross RB. Treatment variables affecting facial growth in complete unilateral cleft lip and palate. Cleft Palate J 1987;24:5-77.  Back to cited text no. 4
Buschang PH, Porter C, Genecov E, Genecov D, Sayler KE. Face mask therapy of preadolescents with unilateral cleft lip and palate. Angle Orthod 1994;64:145-50.  Back to cited text no. 5
Chen KF, So LL. Sagittal skeletal and dental changes of reverse headgear treatment in Chinese boys with complete unilateral cleft lip and palate. Angle Orthod 1996;66:363-72.  Back to cited text no. 6
So LL. Effects of reverse headgear treatment on sagittal correction in girls born with unilateral complete cleft lip and cleft palate – Skeletal and dental changes. Am J Orthod Dentofacial Orthop 1996;109:140-7.  Back to cited text no. 7
Friede H, Lennartsson B. Forward traction of the maxilla in cleft lip and palate patients. Eur J Orthod 1981;3:21-39.  Back to cited text no. 8
Ranta R. Protraction of the cleft maxilla. Eur J Orthod 1988;10:215-22.  Back to cited text no. 9
Sarnäs KV, Rune B. Extraoral traction to the maxilla with face mask: A follow-up of 17 consecutively treated patients with and without cleft lip and palate. Cleft Palate J 1987;24:95-103.  Back to cited text no. 10
Tindlund RS, Rygh P, Bøe OE. Orthopedic protraction of the upper jaw in cleft lip and palate patients during the deciduous and mixed dentition periods in comparison with normal growth and development. Cleft Palate Craniofac J 1993;30:182-94.  Back to cited text no. 11
Dogan S. The effects of face mask therapy in cleft lip and palate patients. Ann Maxillofac Surg 2012;2:116-20.  Back to cited text no. 12
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Tindlund RS, Rygh P. Maxillary protraction: Different effects on facial morphology in unilateral and bilateral cleft lip and palate patients. Cleft Palate Craniofac J 1993;30:208-21.  Back to cited text no. 14
Vig KW. Orthodontic considerations applied to craniofacial dysmorphology. Cleft Palate J 1990;27:141-5.  Back to cited text no. 15
Tindlund RS. Skeletal response to maxillary protraction in patients with cleft lip and palate before age 10 years. Cleft Palate Craniofac J 1994;31:295-308.  Back to cited text no. 16
Ishikawa H, Kitazawa S, Iwasaki H, Nakamura S. Effects of maxillary protraction combined with chin-cap therapy in unilateral cleft lip and palate patients. Cleft Palate Craniofac J 2000;37:92-7.  Back to cited text no. 17
Kim JH, Viana MA, Graber TM, Omerza FF, BeGole EA. The effectiveness of protraction face mask therapy: A meta-analysis. Am J Orthod Dentofacial Orthop 1999;115:675-85.  Back to cited text no. 18
Jia H, Li W, Lin J. Maxillary protraction effects on anterior crossbites. Repaired unilateral cleft versus noncleft prepubertal boys. Angle Orthod 2008;78:617-24.  Back to cited text no. 19
Nanda R. Protraction of maxilla in rhesus monkeys by controlled extraoral forces. Am J Orthod 1978;74:121-41.  Back to cited text no. 20
Itoh T, Chaconas SJ, Caputo AA, Matyas J. Photoelastic effects of maxillary protraction on the craniofacial complex. Am J Orthod 1985;88:117-24.  Back to cited text no. 21
Hiraga J. Biomechanical study of maxillaty protraction on the craniofacial complex. J Jpn Orthod Soc 1991;50:33-47.  Back to cited text no. 22
Ishii H, Morita S, Takeuchi Y, Nakamura S. Treatment effect of combined maxillary protraction and chincap appliance in severe skeletal class III cases. Am J Orthod Dentofacial Orthop 1987;92:304-12.  Back to cited text no. 23
Singla S, Utreja A, Singh SP, Lou W, Suri S. Increase in sagittal depth of the bony nasopharynx following maxillary protraction in patients with unilateral cleft lip and palate. Cleft Palate Craniofac J 2014;51:585-92.  Back to cited text no. 24
da Luz Vieira G, de Menezes LM, de Lima EM, Rizzatto S. Dentoskeletal effects of maxillary protraction in cleft patients with repetitive weekly protocol of alternate rapid maxillary expansions and constrictions. Cleft Palate Craniofac J 2009;46:391-8.  Back to cited text no. 25
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  [Figure 1], [Figure 2], [Figure 3], [Figure 4], [Figure 5], [Figure 6]

  [Table 1], [Table 2], [Table 3]


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