Do premolar extractions necessarily result in a flat face? No, when properly indicated

Occlusal Plane Steepness and Profile Change Following TAD-Based One-Step Retraction on Four-Unit Extraction Cases: A Retrospective Study

BACKGROUND

With the introduction of high-tech appliances, anchorage devices, and improved patient awareness of the risks associated with maxillofacial surgery, treating complex situations with orthodontic treatment has become more difficult in recent years. This study was conducted to demonstrate that orienting the occlusal plane, all the dental, skeletal, and soft tissue parameters, would be improved and to find which of these parameters could be correlated with the steepness of the occlusal plane.

MATERIALS AND METHODS

This was a retrospective study including 40 cephalometric interpretations for patients who were planned for four-unit extractions (20 cephalometric radiographies before treatment and 20 after finishing the treatment). All were treated in the same orthodontic clinic with the same protocol using the McLaughlin-Bennett-Trevisi (MBT) prescription, with 22 slots and one-step retraction following four-unit extraction based on temporary anchorage devices (TADs).

RESULTS

There was no significant change in the canting of the occlusal plane, and it remained relatively stable from 6.31° to 7.55°, while all the soft tissue-related cephalometric measurements were reduced significantly, except the nasolabial angle, as the relation of the upper and lower lip to the esthetic line of Ricketts' (E-Line) was reduced by 2.91 and 2.46°, respectively; furthermore, the angle of convexity was reduced from 10.92° to 9.79°. Besides, the upper incisor display was reduced by 0.38° Conclusions: Both the Frankfort mandibular angle and upper-incisor-to-Frankfort horizontal plane were significant parametric factors associated with profile change after extraction treatment having a positive 0.01-level Pearson association with occlusal plane steepness. Therefore, using the MBT prescription with TAD-based retraction is one of the favorable methods for the management of complex cases.

Iatrogenic retroposition of the lips sequel after bicuspid extraction-a retrospective study

AIM

This study aims to explore the prevalence of Iatrogenic retroposition of the lips sequel (IRLS) after bicuspid extraction, associated dentofacial characteristics and the effectiveness of surgical treatment.

MATERIAL

and methods: Patients with bicuspid extraction as part of an orthodontic treatment plan were retrospectively included. IRLS was identified by clinical evaluation and cephalometric Legan and Burstone analysis. Association of demographic and cephalometric variables were assessed. The effectiveness of combined orthodontic-orthognathic correction of the retroposition of the lips was evaluated.

RESULTS

Out of 144 patients with extracted bicuspids, eight Class I patients, nine Class II patients and five Class III patients were seeking treatment because their lips had retruded as a consequence of compensating orthodontic treatment. Lower jaw bicuspid extraction and a decreased vertical facial height in Class II patients correlated significantly more with IRLS development. Postoperative cephalometric analysis of orthodontic-orthognathic treated patients reported improvement in lip projection and naso-labial angle. Only two Class I patients reported postoperative normalization of the lip position according to Legan and Burstone.

CONCLUSION

The consequence of bicuspid extractions on soft tissue profile differs according to skeletal jaw relation. The impact of orthognathic surgery on IRLS is beneficial, although insufficient to completely correct the facial profile when judged on cephalometric standards.

Treatment of adult patient with hyperdivergent retrognathic phenotype and anterior open bite: report of a case with non-surgical orthodontic approach

Adult patients with anterior open bite and hyperdivergent retrognathic phenotype demand complex treatments, as premolar extractions, molar intrusion or orthognathic surgery. In the present clinical case, a young adult patient without significant growth, with Class I and anterior open bite, was treated with four premolar extractions. The therapeutic result shows good intercuspation, good facial esthetic, good function balance, and stability in a two-year post-fixed treatment follow-up.