www.medigraphic.org.mx Revista Mexicana de Ortodoncia Vol. 5, No. 2 April-June 2017 pp 102-110 CASE REPORT Correction of an skeletal anterior open bite with mini-screws and a modifi ed bite block Corrección de una mordida abierta anterior esquelética mediante miniimplantes y un bite block modifi cado Ángel Eduardo Miranda Salguero,* Alfredo Sánchez Valverde§ ABSTRACT RESUMEN Skeletal anterior open bite may be treated with mini-screws since La mordida abierta esquelética anterior puede ser tratada con mi- they provide an absolute anchorage to correct it through maxillary niimplantes, ya que proveen un anclaje absoluto para corregir me- molar intrusion. With an adequate control a bite block was used diante la intrusión de los molares maxilares con un adecuado con- in this case to help correct the malocclusion. Case report: A 15 trol, en el presente caso se ayudó con un bite block modifi cado. Se year-old male dolichofacial patient with an Angle class II division 1 presenta el caso de un paciente de 15 años de edad, dolicofacial, malocclusion, a -4.5 mm anterior open bite and incompetent lips is con una maloclusión clase II subdivisión 1, mordida abierta anterior hereby presented. Etiology: reduced anterior upper facial height. The de -4.5 mm e incompetencia labial. Etiología: por una altura facial treatment goal was to obtain a normal anterior overbite decreasing anterior superior disminuida. El objetivo del tratamiento fue conse- the posterior maxillary dentoalveolar height. Orthognathic surgery guir una adecuada sobremordida anterior disminuyendo la altura was indicated but the patient refused it. So the treatment consisted maxilar dentoalveolar posterior. La cirugía ortognática se le indicó in two mini-screws implanted on the palatal side and a modified pero fue rechazada. Por lo tanto se realizó una intrusión molar su- fi xed bite block, activated with elastomeric chains. Results: A molar perior con dos miniimplantes colocados en el paladar más un bite intrusion of 2 mm was achieved; the anterior overbite changed to block modifi cado activado con cadenas elásticas. Resultados: La +2 mm, a mandibular counterclockwise rotation took place and the intrusión molar superior fue de -2 mm, la sobremordida anterior facial profi le was improved. Conclusions: The anterior open bite cambió a +2 mm, hubo autorotación mandibular y se mejoró el per- was corrected with a good control during molar intrusion and without fi l facial. Conclusiones: La mordida abierta anterior fue corregida buccal tipping. con un adecuado control de la intrusión evitando alguna inclinación bucal de los molares. Key words: Open bite, mini-screws, molar intrusion, bite-block. Palabras clave: Mordida abierta, miniimplantes, intrusión molar, bite-block. BACKGROUND INFORMATION the projection of the chin.2 This mandibular position may also decrease the airways. Open bite is a malocclusion of the vertical plane, To differentiate if it is a skeletal or dental open bite due to a lack of anterior contact. It may be of skeletal cephalometric analysis are used. A dental open bite or dental origin.1 The malocclusion is attributed to is characterized by incisors in infraocclusion, while a multifactorial etiology since it may be genetic, anatomical and environmental as well as due to www.medigraphic.org.mx2,3 the development of pernicious oral habits, The * Resident of the Orthodontics Specialty. prevalence of anterior open bite is 3.5% (8 to 17 years § Professor of the Orthodontics Specialty. of age).4 In Mexican population, at early ages, the open bite is related to habits in 96.6% of the cases.5 Division of Post-Graduate Studies and Research Division of the Faculty of Dentistry, National Autonomous University of Mexico. The open bite patient is characterized by adenoid facies or long face syndrome with lip incompetence © 2017 Universidad Nacional Autónoma de México, [Facultad de caused by incisor proclination and lack of overbite, Odontología]. This is an open access article under the CC BY-NC-ND which when combined with habits cause gingival license (http://creativecommons.org/licenses/by-nc-nd/4.0/). 6 infl ammation. The retruded position of the mandible This article can be read in its full version in the following page: decreases the mentocervical distance and shortens http://www.medigraphic.com/ortodoncia Revista Mexicana de Ortodoncia 2017;5 (2): 102-110 103 the premolars and molars are further away from the inclination, torsion, mesiodistal position and the palatal or mandibular planes, Graber et al. indicates vertical position molars, in addition to assessing arch that if their apices are more than 3 mm above these form, inclination of the occlusal plane and the frontal planes it may be considered as a supraeruption.7 A occlusal plane. When performed on upper molars, it is larger degree of divergence of the upper and lower very important to consider control over the resistance occlusal planes indicates the severity of the case.8 of the palatal roots.7 Janson et al. reported that the upper and lower molars In the present case an upper molar intrusion was are more mesially inclined with respect to the occlusal performed trying to have suffi cient control over the fi rst plane, while the apices are accentuated in a distal and second molars to achieve adequate results and inclination in relation to the palatal and mandibular correct the open bite. plane respectively.9 Among the skeletal cephalometric data, the Diagnosis and etiology inclination of the Mandibular Plane will be found increased as well as a downward and rearward A male patient of 14 years and 9 months of age inclination of the mandibular ramus, a short attended the Orthodontics Clinic of the Division of mandibular ramus, a more marked antegonial Post-Graduate Studies and Research, UNAM, with notch and a shortened posterior facial height, which the following reason for consultation: «My upper teeth increases the mandibular angle and the anterior facial are too forward». Regarding pathological data, the height.2 If the problem is in the maxilla an increased patient mentioned being under treatment for rhinitis. inclination of the palatal plane will be present due to Oral habits: Mouth breathing. The facial photographs excess of posterior growth or to poor anterior growth showed a convex profi le, lip incompetence and poor of the maxilla.10 In addition to the vertical analysis of projection of the chin; the smile photograph revealed the anterior and posterior facial height, the height of an anterior open bite (Figure 1). Upon intraoral the dentoaveolar processes must be measured as examination the patient presented a right molar class indicated by Sean Biggerstaff et al.11 When a vertical II malocclusion, bilateral canine class II, bilateral problem is evident in a skeletal open bite, Sassuoni posterior cross bite (-2 mm), anterior open bite (-4.5 described that the occlusal, palatal and mandibular mm) and spaces between the incisors (Figures 2 planes make a closer convergence near the posterior and 3). In the panoramic radiograph no caries may portion of the face.12 be observed, there are good root inclinations and Several therapies have been described to correct third molars are under development. The analysis the skeletal or dental open bite such as functional of the lateral head fi lm identifi ed a skeletal class II education of the tongue; extraction of fi rst premolars, due to mandibular retro position (ANB: 6o, Convexity second premolars or fi rst molars; high-pull headgear, of Ricketts: 5 mm), vertical growth: (SN-PM: 41o, chin cup, elastics, multi-loop arch wires (MEAW), bite Facial Axis: 83o), dental biproclination (1U-SN: 110o, blocks, tongue cribs and functional appliances. In the IMPA: 101o). As etiology it was determined that a skeletal open bite orthognathic surgery will always be poor anterior maxillary growth and an increased the standard treatment.8,13-17 posterior maxillary height (N-ENA: 52 mm palatal In the last decade molar intrusion through the plane: -7o) was the cause of the malocclusion (Figure use of mini-implants has been described to correct 4). Through the use of CT cone-beam it may be the skeletal open bite thus causing a decrease in observed that there is no damage to the cortical bone incisor extrusions. It has also been described to (Figure 5). provide favorable cosmetic results such as a forward rotation of the mandible and a reduction in anterior Treatment goals facial height. It has even beenwww.medigraphic.org.mx used as an alternative for patients who have not agreed to orthognathic Facial: to improve the profile, decrease lip surgery.18,19 incompetence and improve incisor exposure during There are different ways to perform molar intrusion smile. Skeletal: to correct the skeletal open bite, favor with mini-implants, whether placed palatally, labially a CCW mandibular rotation and control the vertical or in both sides as well as with the help of other dimension. Dental: coordinate arches, achieve molar appliances.17,18,20-23 and canine class I, retrocline the incisors, match In Graber’s book it is stated that molar intrusion midlines, and obtain occlusal contact. Functional: with mini-implants must be designed to provide three- to improve respiratory function through open bite dimensional control of the tooth regarding rotation, closure. 104 Miranda SAE et al. Correction of an skeletal anterior open bite with mini-screws and a modifi ed bite block Figure 1. Initial facial photographs. Figure 2. Initial intraoral photographs. Treatment alternatives implants to the device. This would allow an intrusion without causing undesirable inclination movements. 1. Orthognathic surgery: LeFort I surgery for maxillary impaction. The patient did not accept this treatment Treatment progress alternative. 2. Extraction of four fi rst premolars: This would allow Fixed appliances: 0.022” × 0.028” slot Edgewise the correction but could affect the facial profi le in the brackets and tubes.