Evaluation of tongue pressure on the loop of transpalatal arch with acrylic button during deglutition in hyperdivergent patients

Orthodontic correction of a skeletal Class II malocclusion with severe gummy smile by total intrusion of the maxillary dentition

A 22-year-old woman visited the hospital complaining of lip protrusion, crowded teeth, and a gummy smile. The clinical examination showed a convex profile with a hyperdivergent mandible and a severe gummy smile in both anterior and posterior regions. The unstable mandible position was considered during treatment planning, and a targeted mechanic system was carefully designed. Temporary skeletal anchorage devices in the posterior dental region and a transpalatal arch were introduced as anchorage for the intrusion of the entire maxillary dentition and controlled retraction of the anterior teeth. Based on effective and simple mechanisms, we successfully eliminated the severe gummy smile and improved the facial aesthetics with the aid of conventional appliances. This approach provided an alternative option to orthognathic surgery or bulky invasive miniscrews for treatment of skeletal Class II malocclusion with severe gummy smile.

Intrusion of the maxillary posterior teeth with a single buccal mini-implant positioned bilaterally in young adults with a tendency towards hyperdivergence: A clinical study

BACKGROUND

Skeletal anchorage systems have been used for intrusion of the posterior teeth with satisfactory results. To achieve this, mini-implants are placed at anatomically challenging sites such as the palate or require several mini-implants to produce the desired effect.

OBJECTIVE

To determine the magnitude of intrusion of the maxillary posterior teeth achieved on a continuous arch wire using a single buccal mini-implant placed bilaterally in young patients with a tendency towards hyperdivergence and to evaluate its influence on the skeletal, dental and soft-tissue structures.

METHODS

A total of 17 patients with proclination of the anterior teeth, tendency towards hyperdivergence and clockwise rotation of the mandible were selected. First premolars were extracted as part of treatment protocol. A 0.022-MBT bracket prescription was used. Mini-implants were placed bilaterally on the buccal aspect at the mucogingival junction or slightly gingival to it between the maxillary second premolar and first permanent molar. A total of 200 g of intrusive force was placed from a continuous 0.019 × 0.025 inch stainless-steel arch wire to the mini-implant by means of an elastomeric thread on both sides. Lateral cephalograms and study models were taken before the start of intrusion and six months later. Parametric and non-parametric tests were done to assess treatment results.

RESULTS

Significant intrusion was observed in the maxillary molar and premolar region with tendency towards intrusion in the anterior region. There was significant decrease in lower anterior facial height (LAFH) with anti-clockwise mandibular rotation, decrease in facial proportion index and total facial height. No changes were observed in the transverse plane.

CONCLUSION

Intrusion of the permanent maxillary molar can be achieved on a continuous arch wire with a single buccal mini-implant placed bilaterally with improvement in facial aesthetics, especially in the vertical plane. This method may be beneficial in patients with borderline vertical discrepancy treated with conventional friction mechanics during space closure after first premolar extractions.