Treatment of vertical maxillary excess without open bite in a skeletal Class II hyperdivergent patient.

A 20-year-old woman visited the office complaining of a gummy smile and lip protrusion. She was diagnosed with vertical maxillary excess without open bite and skeletal Class II hyperdivergent pattern. She refused the surgical-orthodontic treatment option, although she wanted to correct the gummy smile and retruded chin. Differential intrusion of anterior and posterior teeth in both arches was necessary to maximize the skeletal treatment effects. In the maxilla, one palatal temporary anchorage device (TAD), an archwire with an accentuated curve of Spee, and a transpalatal arch were applied. In the mandible, an archwire with a reverse curve of Spee and two vertically positioned TADs were used. These simple mechanics contributed to the effective intrusion of the total upper and lower arches, correction of the gummy smile, and mandibular counterclockwise rotation, offering an alternative to orthognathic surgery for this patient.

Distalization pattern of whole maxillary dentition according to force application points.

OBJECTIVE: The purpose of this study was to observe stress distribution and displacement patterns of the entire maxillary arch with regard to distalizing force vectors applied from interdental miniscrews. METHODS: A standard three-dimensional finite element model was constructed to simulate the maxillary teeth, periodontal ligament, and alveolar process. The displacement of each tooth was calculated on x, y, and z axes, and the von Mises stress distribution was visualized using color-coded scales. RESULTS: A single distalizing force at the archwire level induced lingual inclination of the anterior segment, and slight intrusive distal tipping of the posterior segment. In contrast, force at the high level of the retraction hook resulted in lingual root movement of the anterior segment, and extrusive distal translation of the posterior segment. As the force application point was located posteriorly along the archwire, the likelihood of extrusive lingual inclination of the anterior segment increased, and the vertical component of the force led to intrusion and buccal tipping of the posterior segment. Rotation of the occlusal plane was dependent on the relationship between the line of force and the possible center of resistance of the entire arch. CONCLUSIONS: Displacement of the entire arch may be dictated by a direct relationship between the center of resistance of the whole arch and the line of action generated between the miniscrews and force application points at the archwire, which makes the total arch movement highly predictable.

Distalization pattern of whole maxillary dentition according to force application points / 대한치과교정학회지

OBJECTIVE: The purpose of this study was to observe stress distribution and displacement patterns of the entire maxillary arch with regard to distalizing force vectors applied from interdental miniscrews. METHODS: A standard three-dimensional finite element model was constructed to simulate the maxillary teeth, periodontal ligament, and alveolar process. The displacement of each tooth was calculated on x, y, and z axes, and the von Mises stress distribution was visualized using color-coded scales. RESULTS: A single distalizing force at the archwire level induced lingual inclination of the anterior segment, and slight intrusive distal tipping of the posterior segment. In contrast, force at the high level of the retraction hook resulted in lingual root movement of the anterior segment, and extrusive distal translation of the posterior segment. As the force application point was located posteriorly along the archwire, the likelihood of extrusive lingual inclination of the anterior segment increased, and the vertical component of the force led to intrusion and buccal tipping of the posterior segment. Rotation of the occlusal plane was dependent on the relationship between the line of force and the possible center of resistance of the entire arch. CONCLUSIONS: Displacement of the entire arch may be dictated by a direct relationship between the center of resistance of the whole arch and the line of action generated between the miniscrews and force application points at the archwire, which makes the total arch movement highly predictable.