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

Orthodontic considerations in hypodivergent craniofacial patterns

This article examines the characteristics of hypodivergent craniofacial patterns and explores treatment modalities in response to these features. It discusses the impact of robust masticatory muscles, which produce heavy occlusal forces. In addition, it examines the use of Botox or splints to reduce gonial angles in individuals with a square face. A nonextraction treatment approach supported by temporary skeletal anchorage devices is recommended; however, if anatomical limitations persist, extraction may be necessary when arch expansion, molar distalization, incisor proclination, or interproximal reduction cannot create the necessary space. In hypodivergent cases where a nonextraction approach is impractical, a single-arch extraction strategy may be considered to prevent a reduction in the vertical dimension. Emphasizing esthetics, particularly maxillary incisor display, a protocol of total arch extrusion of the maxillary dentition assisted with temporary skeletal anchorage device, bite raisers, and interarch elastics is suggested.

Dentoalveolar effects of skeletally anchored extrusion arch in anterior open bite patients: A prospective clinical trial

OBJECTIVE

The purpose of this prospective clinical trial was to explore the dental and soft tissue changes accompanying the use of skeletally anchored nickel-titanium (NiTi) extrusion arch in the correction of anterior open bite (AOB).

MATERIAL AND METHODS

Twenty female patients with a mean age of 16.5 ± 1.5 years and a mean dentoalveolar AOB of 2.38±0.7 mm participated in this study. All patients were treated with an maxillary 0.017×0.025-in NiTi extrusion arch, with the aid of miniscrews inserted between the maxillary second premolars and first molars bilaterally, to act as indirect anchorage. Three-dimensional digital models and lateral cephalometric radiographs were taken just before the insertion of the extrusion arch (T0) and after 10 months (T1). Paired-sample t-tests were used in analyzing the data, to evaluate the changes after treatment (T1-T0). A significance level of p < 0.05 was used.

RESULTS

AOB was successfully closed in all patients, with a 4.35 ± 0.61 mm increase in the overbite. Maxillary incisors significantly extruded (2.52 ± 1.02 mm) and significantly reclined (5.78 ± 0.77°), with a resultant decrease in the overjet of 1.58 ± 0.5mm. A significant intrusion of maxillary first molars with no change in their inclination was observed. The upper lip showed a significant retraction tendency to the E-plane, and a significant increase in the nasolabial angle was observed.

CONCLUSION

The skeletally anchored NiTi extrusion arch was an effective technique in treating AOB, with no adverse effects on the molars.

Stability of anterior open bite cases treated with upper and lower extrusion arches in adults: a follow-up study

OBJECTIVES

To investigate the post-treatment stability of anterior open bite (AOB) cases treated with upper and lower extrusion arches in adults.

MATERIALS AND METHODS

23 patients with AOB were treated with extrusion arches and evaluated for dentoskeletal changes using lateral cephalometric radiographs before treatment (T0), after treatment (T1), and 12 months post-treatment (T2). Patients received bondable tongue spurs and vacuum-formed retainers as post-treatment retention/stability measures for 12 months. Post-treatment stability was further assessed qualitatively by the Photographic Openbite Severity Index.

RESULTS

All the cases showed positive overlap between the anterior teeth at the end of orthodontic treatment, and 20 of 23 treated patients attended the recall visit after 12 months. A total of 85% of the cases maintained positive overlap at least 1 year post-treatment, 10% showed edge-to-edge bite, and only 5% showed no overbite.

CONCLUSIONS

Treatment of AOB in adults with extrusion arches proved to be stable 1 year post-treatment. Changes in the overbite after 1 year of follow-up were not significant.