A prospective clinical trial of the effects produced by the extrusion arch in the treatment of anterior open bite

Abstract

Aim To evaluate the maxillary dentition effects of the extrusion arch for anterior open bite (AOB) correction in mixed dentition patients. Materials and methods Fourteen subjects with an initial mean age of 9.17 ± 1.03 years presenting with dentoalveolar AOB (mean − 1.28 ± 1.46 mm) and normal facial pattern (FMA = 25.76°) were treated with an extrusion arch. The mean treatment period was 7.79 ± 2.58 months. Lateral cephalograms and dental models were taken before (T0) and after the correction of AOB (T1). Data were analyzed using paired t test to evaluate differences between T0 and T1. For all tests, a significance level of P < .05 was used. Results All patients achieved positive overbite at T1, with a mean increase of 3.07 mm. The maxillary incisors extruded 1.94 mm. Retroclination of the maxillary incisors (− 6.15°) and an increase in the interincisal angle (5.57°) were observed. There was a significant decrease in the distance between the incisal edge of the maxillary incisors and the molars (− 2.21 mm). There was significant mesial tipping of the maxillary molar (− 11.49°). Significant reductions of overjet (− 1.65 mm), arch perimeter (− 3.02 mm), and arch length (− 2.23 mm) were noted. The transverse maxillary intermolar distance did not change significantly. Conclusions The use of a maxillary extrusion arch was effective in the treatment of AOB. Overbite increased due to incisor extrusion, as well as retroinclination and overjet reduction. However, side effects, such as mesial molar tipping and decreases in arch perimeter and length might occur.

Effect of maxillary and mandibular extrusion arches on dentoskeletal changes in adults with anterior open bite: a quantitative analysis

“…Double extrusion arches uprighted maxillary and mandibular incisors, leading to a significant increase in the interincisal angle by 12.818, in agreement with previous studies. 4,13 The positive overlap was maintained at T3, in agreement with other studies investigating different mechanics in the treatment of AOB. 14,15 In AOB treatment, it is essential to intrude molars or at least avoid molar extrusion to prevent any possible interference with bite closure and a subsequent increase in AFH and LAFH.…”

“…Previous work reported positive vertical overlap between the upper and lower anterior teeth in 7.79 months when the extrusion arch was employed in the maxillary arch only. 4 The combined mechanics of maxillary and mandibular extrusion arches used in the current study shortened the duration of treatment of AOB because both the upper and lower incisors were extruded, and the upper and lower posterior teeth were intruded. Double extrusion arches uprighted maxillary and mandibular incisors, leading to a significant increase in the interincisal angle by 12.818, in agreement with previous studies.…”

“…Cephalograms have been extensively used as standard radiographs for evaluating orthodontic treatment in literature. 4 Cone-beam computed tomography can be a more accurate assessment tool for dental measurements without superimpositions in the three planes of space. 10 However, patients would be exposed to more hazardous radiation, which was not justifiable in the current study.…”

“…2,3 It is the opposite of the well-known, one-couple intrusion arch system, comprising an overlay arch with an asymmetric V bend that uses a determinate one-couple force system to extrude maxillary incisors and intrude first molars, thus tipping the occlusal plane and closing the AOB. 4 Extrusion arches applied only to the maxillary dentition showed successful closure of AOB in the mixed dentition. 4 However, in cases with large AOB, the use of one maxillary arch might result in unsightly gingival display.…”

“…4 Extrusion arches applied only to the maxillary dentition showed successful closure of AOB in the mixed dentition. 4 However, in cases with large AOB, the use of one maxillary arch might result in unsightly gingival display. 5 Therefore, the placement of a complementary mandibular extrusion arch, in addition to that in the maxillary arch, was used in the current study.…”