Several treatment options for anterior open bite in adults are described in the literature, all depending on the type of open bite. Orthodontic treatment is enough for dentoalveolar open bite, whereas the skeletal open bite is treated with other approaches such as orthognathic surgery with Le Fort I osteotomy, ortho-surgical procedure or repositioning of the condyle [9]. As alternative to the conventional ortho-surgical treatment, the use of skeletal anchorage by means of mini-plates has been described in terms of orthodontic mechanics and dental movements. The intrusion of upper molars by using mini-plates allows counter-clockwise rotation of the mandible without extruding the upper incisors and affecting the temporomandibular joint [10]. Moreover, another advantage compared to the orthognathic surgery is the possibility of performing outpatient procedures under local anesthesia, which reduces morbidity, costs and chair time, as in the case reported here [5, 11].

One of the concerns regarding the treatment of open bite in adults is the stability of result, since relapses are commonly reported in the literature [1]. For some authors, extraction of upper premolars in Class II patients improves the therapeutic stability as retention helps in the lip positioning and, when associated with loss of anchorage, facilitates the treatment. The orthodontic results associated with extractions and use of mini-plates in the zygomatic buttress can improve the profile of the soft tissues, provide good control of facial height, and correct the anterior open bite efficiently due to intrusion of molars and verticalization of incisors [12, 13].  In a similar case report, the advantages cited elsewhere and described in our work were also found [14]. 

Considering the high rate of malocclusion relapse, the use of retention is important after removal of the appliance and mini-plates [1,15]. In order to minimize the relapse, installation of 3x3 lingual lower retainer and upper Hawley arch is indicated in the final of the treatment [15]. Anterior maxillary retention causes reduction in the angle ANB, which indicates a maxillo-mandibular relationship in the antero-posterior sense, thus improving the patient’s facial profile [16]. Loss of anchorage is a worrying factor in orthodontics, and for small spaces in the mandible where absolute anchorage is desired, mini-screws are the solution. In this case, mini-screws were also used to achieve verticalization of the right lower second molar, which was mesially inclined, thus counteracting any side effect on the anterior teeth in case of verticalization by using conventional technique [17]. Anterior mandibular rotation tends to cause a passive lip sealing due to reduction in the anterior lower facial height (ALFH). The smile aesthetics is also changed positively as the intrusion of molars reduces the posterior dentoalveolar height, which prevents excessive anterior gingival exposure [17].

Another advantage of skeletal anchorage compared to conventional orthodontic mechanics for intrusion of molars is the necessity for removable devices to correct the open bite, such as extra-oral appliances and/or inter-maxillary elastics, which does not depend on the patient’s cooperation [18]. The main dento-eskeletal and aesthetic effects associated with open bite correction with skeletal anchorage can be described as follows: levelling of occlusal plane by intrusion of molars, increase of vertical inter-incisal trespass, decrease of ALPH, reduction in the mandibular plane angle, counter-clockwise mandibular rotation, reduction in the Class II skeletal discrepancy, correction of gingival smile, and improvement of lip sealing and facial convexity [19].

In view of the references used and of the results found, we have concluded that the surgical installation of orthodontic mini-plates for treatment of anterior open bite was effective, safe and little invasive. In this way, it was possible not only to correct the malocclusion, but also to achieve functional and aesthetic gains.