Displacement pattern of the anterior segment using antero-posterior lingual retractor combined with a palatal plate

Abstract

Objective: To evaluate and compare the effects of two appliances on the en masse retraction of the anterior teeth anchored by temporary skeletal anchorage devices (TSADs).

Methods: The sample comprised 46 nongrowing hyperdivergent adult patients who planned to undergo upper first premolar extraction using lingual retractors. They were divided into three groups, based on the lingual appliance used: the C-lingual retractor (CLR) group (group 1, n = 16) and two antero-posterior lingual retractor (APLR) groups (n = 30, groups 2 and 3). The APLR group was divided by the posterior tube angulation; posterior tube parallel to the occlusal plane (group 2, n = 15) and distally tipped tube (group 3, n = 15). A retrospective clinical investigation of the skeletal, dental, and soft tissue relationships was performed using lateral cephalometric radiographs obtained pretreatment and post en masse retraction of the anterior teeth.

Results: All groups achieved significant incisor and canine retraction. The upper posterior teeth did not drift significantly during the retraction period. The APLR group had less angulation change in the anterior dentition, compared to the CLR group. By changing the tube angulation in the APLR, the intrusive force significantly increased in the distally tipped tube of group 3 patients and remarkably reduced the occlusal plane angle.

Conclusions: Compared to the CLR, the APLR provides better anterior torque control and canine tipping while achieving bodily translation. Furthermore, changing the tube angulation will affect the amount of incisor intrusion, even in patients with similar palatal vault depth, without the need for additional TSADs.

Keywords: C-lingual retractor; Intrusion; Lingual orthodontics; Mini-implant.

Conflict of interest statement

The authors report no commercial, proprietary, or financial interest in the products or companies described in this article.

Figures

Figure 1. The occlusal diagrams and intraoral photos. A-C, The C-lingual retractor and D-F, the antero-posterior lingual retractor. A, No posterior orthodontic appliance is in place. B, Pretreatment and C, Post en masse retraction by the C-lingual retractor. D-F, The posterior teeth are splinted buccally and the guide bar and posterior tubes are in place. E, Pretreatment and F, Post en masse retraction by the antero-posterior lingual retractor.

Figure 2. Schematic illustrations of the appliance in each group (lateral view; left column); lateral cephalograms at pretreatment and post en masse retraction (middle column); and maxillary superimposition (right column). A, The C-lingual retractor group (i.e., group 1) had clockwise rotation of the anterior segment during retraction. B, The antero-posterior lingual retractor with parallel tube group (i.e., group 2) had intrusion of the anterior segment with less clockwise moment. C, The antero-posterior lingual retractor with distally tipped tube group (i.e., group 3) had the greatest amount of intrusion on the anterior segment. Extrusion of the posterior segments did not occur in group 2 or group 3.

Figure 3. Soft tissue and skeletal cephalometric analysis. 1, The upper lip to the E line; 2, the lower lip to the E line; 3, the sella-nasion to the palatal plane angle (SN-PP); 4, the SN-anatomic occlusal plane angle (SN-Occ); 5, the SN to the mandibular plane angle (SN-Mn); 6, the distance between the pterygoid vertical plane and point A (PTV-A); 7, the distance between the pterygoid vertical plane and point B (PTV-B); and 8, the lower anterior face height (LAFH; ANS-Me). Refer Table 2 for definitions of the landmarks.

Figure 4. Dental cephalometric analysis, based on the angular and linear measurements. 1, The SN to the maxillary canine angle (SN-C); 2, the SN to the maxillary incisor angle (SN-U1); 3, the SN to the maxillary first molar angle (SN-U6); 4, the mandibular plane to mandibular incisor angle (MP-L1); 5, the mandibular plane to mandibular first molar angle (MP-L6); 6, the distance between the pterygoid vertical plane and the maxillary incisor tip (PTV-U1); 7, the distance between the pterygoid vertical plane and the maxillary canine tip (PTV-C); 8, the distance between the pterygoid vertical plane and the maxillary first molar centroid (PTV-U6); 9, the distance between the palatal plane and the maxillary incisor tip (PP-U1); 10, the distance between the palatal plane and the maxillary canine tip (PP-C); 11, the distance between the palatal plane and the maxillary first molar centroid (PP-U6); 12, the distance between the mandibular lingual cortex and the mandibular first molar centroid (LC-L6); 13, the distance between the mandibular plane and the mandibular incisor tip (MP-L1v); and 14, the distance between the mandibular plane and the mandibular first molar centroid (MP-L6v). Refer Table 2 for definitions of the landmarks.