the anterior open - bite can be defined as the presence of negative overbite between the incisal edges of the maxillary and mandibular teeth , with the posterior teeth in occlusion14 . generally , an anterior open - bite is a kind of malocclusion that causes esthetic problems , impairs mastication and articulation , thus creating unfavorable conditions for a child 's emotional development5 . in the mixed dentition , the prevalence of open - bite can reach 17%6 , caused by factors such as the partial eruption of the incisors , abnormal size of lymphoid tissue provoking alterations in the tongue 's posture , persistence of infantile swallow , and the occurrence of oral habits7 . according to many authors , the incidence decreases with age6,8,9 , stabilizing around 2% in caucasian and 16% in black african - american teenagers10 . this decrease accounts for normal occlusal development , neural maturation of the child favoring the cessation of oral habits , the decrease in size of adenoids , and the establishment of normal adult swallow2,11 . in the etiology of the anterior open - bite there are factors related to oral habits , abnormal size or function of the tongue , oral breathing , vertical growth pattern ( predisposing to open - bite ) , and congenital or acquired diseases11 . among the most frequent habits are finger - sucking , pacifiers , altered labial postures and tongue habits2 . vertical malocclusions result from the interaction of several etiologic factors , with genetic and/or environmental origin . the prognosis may be good to poor according to the severity and associated etiology . swallowing with tongue thrusting is frequently observed in children up to ten years old with or without open - bite . other aspects that may break the oral balance , as adenoid hypertrophy , increased tonsils , allergy , excess of nasal cartilage , septal deviation , and chronic coryza , may lead to mouth breathing and anterior tongue positioning during swallowing , thereby affecting the position of incisors , both inducing buccal movement and limitating their correct eruption13 . there are three types of open - bite malocclusion in the mixed dentition period(1 ) : dentoalveolar , skeletal and a combined open - bite . most skeletal open - bites are probably at least partially attributable to abnormal perioral muscle function14 . in skeletal open - bite there are craniofacial dysplasias , characterized by a counter - clockwise rotation of the palatal process , associated with a longer anterior face height , large gonial angle , short ramus , and maxillary and mandibular dentoalveolar hyperplasia1,2,11,15 . many authors emphasize that the skeletal open - bite should be treated early in the mixed dentition3,4,16 , since besides interfering with facial growth , the early treatment improves facial appearance and the child 's self - esteem , reducing the possibility of relapse and thereby increasing the stability17 . taking this into account , the long - term stability of anterior open - bite patients aged nearly 12 years old treated with fixed appliances and without extractions was studied18 . the authors concluded that 61.9% of the patients presented stable occlusion . in another study , lopez - gavito , et al.10 , in 1985 , longitudinally followed 41 patients treated with fixed appliances and headgear for 10 years post - retention , and observed 35% of relapse of approximately 3 mm or more . english16 , in 2002 , stated that , if no treatment is performed , maintenance of the malocclusion in patients with vertical growth pattern with anterior open - bite may result in further need of surgical treatment . the treatment of the open - bite in the late mixed dentition , with a severe tongue thrust or posture problem , may be unsuccessful , and depends on the severity of the malocclusion and the possibility of dentoalveolar compensation7,19 . in addition , a long retention phase is necessary before abnormal perioral muscle function can be reduced . the objective of this work was to document a clinical case of anterior open - bite presented in the mixed dentition , successfully treated by orthodontic and orthopedic methods , emphasizing the importance of early treatment as a means of preventing the need for orthognathic surgery . a female patient , 5 years and 2 months old , with an excessive vertical growth , presenting an anterior open - bite with contact only in the molar region attended our clinic ( figures 1 and 2 ) . this malocclusion was classified as dentoskeletal , initially related to a thumb - sucking resulting in secondary tongue thrust . the patient presented a vertical growth pattern of the face , as can be seen in table 1 . the treatment proposed was a fixed palatal crib soldered on the bihelix appliance ( figure 3 ) , and high pull traction on the mandible for 16 hours a day , applying 500 g of force , during the entire treatment , in an attempt to rotate the mandible counter - clockwise with an intrusive force in the posterior region . following this 3-year process , right after she was subjected to full fixed appliance , with edgewise mechanotherapy , over a 9 month period . at the end of the treatment , it could be noticed , by the clinical characteristics ( figures 5 and 6 ) and also by the cephalometric measures ( table 1 ) , that the initial proposal was successful . the anterior open - bite was corrected , followed by dentoalveolar and growth pattern compensation . these outcomes could be explained by changes in dental inclinations and by the increase of the posterior facial height , which minimized the effects of the longer anterior face height ( table 1 ) . the concern about facial vertical dimensions derives from the fact that they are more difficult to treat , and the results obtained are less stable15,20 . an anterior open - bite may have a good or poor prognosis , depending on its etiology and severity . relapse can reach 25% . a prolonged habit , such as digital sucking , can lead to arrest of the vertical development of the alveolar process , lateral constriction of the maxilla due to increased activity of the perioral muscles , and a more inferior posturing of the tongue . this situation , in the majority of cases , causes posterior crossbite , high palate , extrusion of the posterior teeth and anterior displacement of the maxilla . if this condition remains for a lengthy period , the alterations may persist , even after the habit has been stopped9,21 therefore , during the mixed dentition , it is very important to treat patients adequately3,4 , in order to avoid severe dental changes . these changes may become definitive , reducing the efficiency of the therapeutic methods , thus providing orthognathic surgery as the only option for treatment22 . the interruption of a habit can sometimes be traumatic to children , due to its importance in compensating psychological needs . its sudden interruption can lead to a transfer to another habit , sometimes less socially accepted and more harmful to the child23 . to a motivated patient , who sincerely wants to break a habit not psychologically significant , an appliance will work as a " reminder " , and will help to break the habit . if the habit is compulsive , then psychological help is also required . patients with open - bite often present incompetent upper lip and a compensatory hyperactive lower lip , orbicularis oris and tongue musculature . the anterior seal , necessary for swallowing , is obtained between the upper and lower incisors , contributing to maintenance of the negative overbite . an individual with an excessive vertical growth has a good likelihood of developing an anterior open - bite , and the degree of its severity can be altered by unfavorable environmental factors , such as habits and mouth breathing7 . this case has been stable , and it is believed that it will remain so ( figures 7 and 8) . this may be explained by the fact that treatments were conducted at the appropriate period of development , thus establishing perioral muscular equilibrium , matching the final period of facial growth . the combination of orthodontic and orthopedic treatments was necessary to achieve the best results , as previously suggested7 . it must be pointed out that this patient , if not treated at the correct moment , could have required orthognathic surgery .
a clinical case with anterior open - bite , treated in the mixed dentition , is presented . 
 this approach demonstrates one of the possible approaches of treatment , which is capable of interfering with growth and redirecting its vectors . 
 orthodontic and orthopedic methods were used , consisting of slow maxillary expansion , through a fixed palatal crib soldered in a bi - helix appliance , and high - pull traction on the mandible for 16 hours a day . 
 after eight years of follow - up , stable outcomes were accomplished . 
 these results may be explained by the fact that treatments were performed at the appropriate period of development , thus establishing perioral muscular equilibrium , matching the final period of facial growth . 
 the combination of orthodontic and orthopedic treatments was necessary to prevent the need of further orthognathic surgery treatment .