Analysis of lingual en masse retraction combining a C-lingual retractor and a palatal plate

Abstract

Objectives: To analyze the results of employing en masse retraction of the maxillary anterior dentition using palatal temporary skeletal anchorage devices (TSADs) as the exclusive source of anchorage.

Materials and methods: A retrospective clinical investigation supported by preliminary case reports was performed comparing pretreatment cephalometric radiographs with those taken after en masse retraction of the six anterior teeth. The sample consisted of 35 nongrowing patients with an average age of 22.9 years. The average retraction period was 10 months (range, 6-15 months). No brackets or bands were placed on the posterior dentition during retraction. A total of 35 C-palatal plates (C-plates) were used as the only source of anchorage for maxillary anterior retraction with the C-lingual retractor (C-retractor), thereby eliminating the need for bonded or banded anchor teeth. The cephalometric radiographs were analyzed for differences between pretreatment and postretraction variables that included skeletal, dental, and soft tissue relationships.

Results: Significant incisor and canine retraction was achieved in all patients, and the upper posterior teeth did not show significant mesial drifting during the retraction period. According to the length of the lever arm of the C-retractor, tooth movement showed different directions.

Conclusions: En masse retraction of the six anterior teeth with good torque control and effective intrusion is possible using palatal TSADs as the only source of anchorage.

Figures

Figure 1

(A) Schematic illustration of lingual biocreative therapy. (B) Occlusal view of C-lingual retractor and C-palatal plate combined en masse retraction. (C, D) Intraoral photographs immediately after force application and after anterior retraction.

Figure 2

Treatment progress lateral cephalograms. (A, B) Group 1 patients (SN-U1 105°) needed controlled lingual tipping, so a shorter lever arm was recommended. The lever arm of the retractor was located between the upper central incisor and lateral incisor.

Figure 3

Soft tissue and skeletal cephalometric analysis. 1: upper lip to E-line; 2: lower lip to E-line; 3: SN to palatal plane angle (SN-PP); 4: SN-anatomic occlusal plane angle (SN-Occ); 5: SN to mandibular plane angle (SN-Mn); 6: pterygoid vertical plane to A point distance (PTV-A); 7: pterygoid vertical plane to B point distance (PTV-B); 8: lower anterior face height (LAFH; ANS-Me).

Figure 4

Dental cephalometric analysis: angular and linear measurements. 1: SN to maxilliary incisor angle (SN-U1); 2: SN to maxillary first molar angle (SN-U6); 3: mandibular plane to mandibular incisor angle (MP-L1); 4: mandibular plane to mandibular first molar angle (MP-L6); 5: pterygoid vertical plane to maxillary incisor tip distance (PTV-U1); 6: pterygoid vertical plane to maxillary first molar centroid distance (PTV-U6); 7: palatal plane to maxillary incisor tip distance (PP-U1); 8: palatal plane to maxillary first molar centroid distance (PP-U6); 9: mandibular lingual cortex to mandibular first molar centroid distance (LC-L6); 10: mandibular plane to mandibular incisor tip distance (MP-L1); 11: mandibular plane to mandibular first molar centroid distance (MP-L6).