Camouflage treatment of skeletal Class III malocclusion with multiloop edgewise arch wire and modified Class III elastics by maxillary mini-implant anchorage

Abstract

Objective: To evaluate the effect of the multiloop edgewise arch wire (MEAW) technique with maxillary mini-implants in the camouflage treatment of skeletal Class III malocclusion.

Materials and methods: Twenty patients were treated with the MEAW technique and modified Class III elastics from the maxillary mini-implants. Twenty-four patients were treated with MEAW and long Class III elastics from the upper second molars as control. Lateral cephalometric radiographs were obtained and analyzed before and after treatment, and 1 year after retention.

Results: Satisfactory occlusion was established in both groups. Through principal component analysis, it could be concluded the anterior-posterior dental position, skeletal sagittal and vertical position, and upper molar vertical position changed within groups and between groups; vertical lower teeth position and Wits distance changed in the experimental group and between groups. In the experimental group, the lower incisors tipped lingually 2.7 mm and extruded 2.4 mm. The lingual inclination of the lower incisors increased 3.5°. The mandibular first molars tipped distally 9.1° and intruded 0.4 mm. Their cusps moved 3.4 mm distally. In the control group, the upper incisors proclined 3°, and the upper first molar extruded 2 mm. SN-MP increased 1.6° and S-Go/N-ME decreased 1.

Conclusions: The MEAW technique combined with modified Class III elastics by maxillary mini-implants can effectively tip the mandibular molars distally without any extrusion and tip the lower incisors lingually with extrusion to camouflage skeletal Class III malocclusions. Clockwise rotation of the mandible and further proclination of upper incisors can be avoided. The MEAW technique and modified Class III elastics provided an appropriate treatment strategy especially for patients with high angle and open bite tendency.

Figure 1.

Cephalometric angular measurements. (1) SNA. (2) SNB. (3) ANB. (4) SN-OP. (5) SN-MP. (6) U1-L1. (7) L1-MP. (8) L6-MP. (9) U1-SN.

Figure 2.

Cephalometric liner measurements: FHV (McNamara line) was drawn perpendicular to FH plane from the nasion. a: (1) A-McNamara line. (2) Pog-McNamara line. (3) U1-FHV, perpendicular distance from the edge of upper incisors to FHV. (4) L1-FHV, perpendicular distance from the edge of lower incisors to FHV. (5) U6-FHV, perpendicular distance from the mesial cusp of upper first molar to FHV. (6) L6-FHV, perpendicular distance from the mesial cusp of lower first molar to FHV. (7) U1-PP, perpendicular distance from the edge of upper incisors to palatal plane. (8) L1-MP, perpendicular distance from the edge of lower incisors to mandibular plane. (9) U6-PP, perpendicular distance from the mesial cusp of upper first molar to palatal plane. (10) L6-MP, perpendicular distance from the mesial cusp of lower first molar to mandibular plane. b: (11) S-Go. (12) N-Me. (13) Wits appraisal. (14) E line to upper lip. (15) E line to lower lip.

Figure 3.

Photographs of one patient in the experimental group. (A) Profiles pretreatment and posttreatment, and 1 year after retention. (B) Intraoral photographs pretreatment. (C) Intraoral photographs during treatment. (D) Intraoral photographs posttreatment. (E) Intraoral photographs 1 year after retention.

Figure 4.

Superimpositions of cephalometric tracings on sella-nasion plane at sella at pretreatment (black line) and posttreatment (dotted line). (A) One sample in the experimental group. (B) One sample in the control group.

Figure 5.

Significantly different treatment effects between groups.