Accuracy of planned tooth movement with lingual straight wire technique

Abstract

Objectives To analyze the accuracy of planned tooth movements of torque, tip, rotations, and transverse width values with lingual straight-wire technique. Materials and Methods 40 Caucasian subjects with mean age of 23.9 years, consecutively treated in private practice with a lingual straight-wire appliance (STb, Ormco, Glendora, Calif) were evaluated. Maxillary and mandibular dental casts were taken before treatment (T0), in the setup (T1), and at the end of treatment (T2) and scanned with an intraoral 3D scanner Carestream CS 3600 (Carestream Dental, Atlanta, GA). Virtual models at the three time points were superimposed on T1 using 3D software, and the coordinates were exported as a set of x, y, and z values. Angular and linear measurements were analyzed to measure torque, tip, rotation movements, and transverse intra-arch widths. Changes among the three time points were analyzed with Friedman's nonparametric test. Results A general increase in torque was recorded in the setup and in the final result, except for the maxillary molars. Torque, tip, and rotation movement mean accuracy was ≥84% for incisors, canines, and premolars. A general increase in transverse width was measured in the setup and in the final models, except for the upper second molars, which showed reduced transverse width during treatment. Conclusions The movements planned in the setup to obtain the ideal torque, tip, and rotations actually occurred, except for second molars, which showed less accuracy. Planned expansion of the arches occurred only partially.

Predictability of orthodontic tooth movement with aligners: effect of treatment design

“…As reported for other techniques [ 49 , 50 ], there is no perfect appliance, yet despite the limitations of the system, clinical results with aligners are satisfactory [ 8 , 51 ]. Interpreting our results, we should consider that each orthodontic movement consists of several components; therefore, every result isolating a single movement should be judged as a simplification of a complex reality.…”

Accuracy of lingual straight-wire orthodontic treatment with passive self-ligating brackets and square slot: a retrospective study

“…Another factor to consider is that in the terminal portions of the arch the archwire is more flexible, exerting the so-called "trampoline effect", which limits the transmission of orthodontic forces [ 23 ], not to mention the influence that masticatory forces could have at this level.…”

“…These findings are in line with those of Albertini et al, although they investigated the use of a conventional lingual bracket with rectangular slot (0.018 × 0.025-in.) and found a slightly greater accuracy for angular movements [ 23 ]. These differences could be explained by the imprecision inherent in the measurement method used in both studies.…”

“…This retrospective study was approved by the University of Ferrara Ethics Committee, and the protocol registered as number 7/2022. The sample size was calculated in a study to validate the measurement method used [ 27 ], in a similar fashion to that reported by Albertini et al, who determined a minimum sample of 24 patients [ 23 ]. Therefore, 25 adult patients of Caucasian origin (16 females and 9 males; mean age 26.5 ± 4.3 years) who had undergone non-extractive orthodontic treatment with ALIAS passive self-ligating lingual straight-wire appliances (Ormco, Orange, Cal, USA) were selected retrospectively.…”

“…Although other authors have investigated the clinical efficacy of lingual appliances [ 23 – 26 ], no one has yet investigated the clinical efficacy of orthodontic was therefore to investigate the clinical accuracy of such appliances with respect to the results planned in the digital set-up.…”