الفهرس 
INTRODUCTIONOnly 14 pages are availabe for public view
 |  | from | 107 |  |  |
| | | from | 107 | | |
Abstract
AIM OF THE STUDY
This clinical study aimed to quantify the skeletal and dental changes accompanying the use of a determinate one-couple force system in the treatment of anterior open bite (AOB) in adults.
MATERIALS AND METHODS
Eighteen subjects with a mean age of 20.6 ±2.5 years and an AOB of 3.05 mm ± 1.27 mm were treated with upper and lower extrusion arches after the alignment phase was done. Lateral cephalograms with tooth positioning jigs were taken before placement of the extrusion arch (T1), immediately after closure of the open bite (T2), and at the end of orthodontic treatment (T3). The dental and skeletal changes were statistically analysed using repeated measures analysis of variance (ANOVA) and Bonferroni post hoc test for multiple comparisons at a level of significance (= 0.05).
RESULTS
Successful closure of AOB was achieved following an average duration of intervention of 3.8 months (from T1 to T2) and remained stable at T3. The extrusion arches resulted in a mean change in the overbite of 4.73 ± 1.93 mm due to dental and skeletal changes. The upper and lower incisors were significantly extruded by 2.05 mm ± 0.72 mm and 2.54 mm ± 1.63 mm respectively, and significantly retroclined by 6.36 ± 1.63° and 8.45° ± 3.83°, respectively with a resultant increase in the interincisal angle by 12.80° ± 2.09°. A statistically significant intrusion and mesial tipping (P<0.001) of the maxillary and mandibular first molars were found at T2 with a significant concomitant decrease in the lower anterior facial heights (p<0.001) owing to the slight counterclockwise rotation of the mandible. Dental and skeletal changes remained stable at T3 except for significant reduction in the mesial tipping moment of the maxillary and mandibular first molars. There were no significant changes in SNA, SNB, and ANB angles.
CONCLUSION
AOB was corrected using one-couple force system by a combination of anterior teeth extrusion and retroclination and posterior teeth intrusion. The skeletal changes revealed slight mandibular counterclockwise rotation with reduction in the anterior facial vertical dimension.
CLINICAL RELEVANCE
The use of maxillary and mandibular extrusion arches is an effective approach to close AOB in adult patients without jeopardizing the vertical dimension.