Biomechanics of Lingual Orthodontics and TADs

INTRODUCTION: This study aims to determine the shape and dimension of dental arches from a lingual perspective, and determine shape and size of a straight archwire used for lingual Orthodontics. METHODS: The study sample comprised 70 Caucasian Brazilian individuals with normal occlusion and at least four of Andrew's six keys. Maxillary and mandibular dental casts were digitized (3D) and the images were analyzed by Delcam Power SHAPET 2010 software. Landmarks on the lingual surface of teeth were selected and 14 measurements were calculated to determine the shape and size of dental arches. RESULTS: Shapiro-Wilk test determined small arch shape by means of 25th percentile (P25%) - an average percentile for the medium arch; and a large one determined by means of 75th percentile (P75%). T-test revealed differences between males and females in the size of 12 dental arches. CONCLUSION: The straight-wire arch shape used in the lingual straight wire technique is a parabolic-shaped arch, slightly flattened on its anterior portion. Due to similarity among dental arch sizes shown by males and females, a more simplified diagram chart was designed.

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Dentoskeletal and soft tissue changes associated with miniscrew anchorage in customized lingual orthodontics

Journal of International Medical Research ◽

10.1177/0300060518795541 ◽

2018 ◽

Vol 47 (1) ◽

pp. 84-95

Author(s):

Dawei Liu ◽

Jing Li ◽

Feifei Lei ◽

Xuedong Wang ◽

Yanheng Zhou

Keyword(s):

Soft Tissue ◽

Clinical Effectiveness ◽

Upper Lip ◽

Lingual Orthodontics ◽

Premolar Extraction ◽

Anterior Teeth ◽

Mandibular Plane ◽

Space Closure ◽

Tissue Changes ◽

Soft Tissue Changes

Objectives The goal of this study was to analyze skeletal, dental, and soft tissue changes of patients treated with customized lingual systems and to evaluate the clinical effectiveness of miniscrew anchorage. Methods Nine upper first premolar extraction patients who were treated with customized lingual appliances were included in this study. Miniscrews were used for reinforcement of molar anchorage. Cephalometric films and study models were obtained before treatment (T1), after alignment (T2), and after treatment (T3). Treatment effects were analyzed by cephalometric radiographs and study models. Results The upper anterior teeth were retracted significantly at T2 and T3 (4.41 ± 4.14 mm and 5.51 ± 2.48 mm, respectively). During space closure, the upper first molars showed slight mesial movement (1.50 ± 1.97 mm). The intercanine width of the upper arch increased at T2 (1.59 ± 1.81 mm), but decreased at T3 (0.11 ± 1.00 mm). The sella-nasion-A, A-nasion-B, and mandibular plane angles were not significantly changed at T3. The upper lip showed continuous retraction at both T2 and T3 (1.40 ± 1.46 mm and 2.32 ± 2.48 mm, respectively). Conclusions By using miniscrew anchorage for lingual orthodontics, patients’ dental and soft tissue changes considerably improved and molar anchorage was reinforced.

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