Aug 2026· American Journal of Orthodontics and Dentofacial Orthopedics· 0 citations· 21 references
Medicine
TL;DR
Pretreatment dentoalveolar characteristics were significantly associated with treatment duration in nonextraction CAT, highlighting the influence of biological, behavioral, and treatment-related factors beyond pretreatment records.
Abstract
INTRODUCTION
The objective of this study was to evaluate the associations between pretreatment dentoalveolar characteristics and treatment duration in nonextraction clear aligner therapy (CAT).
Methods
This retrospective cohort study included 296 patients treated with nonextraction CAT. Pretreatment variables were extracted from Invisalign ClinCheck (Align Technology, Santa Clara, Calif) digital treatment planning software and included deviations in overjet and overbite from a 3 mm reference, arch irregularities, midline deviation, and posterior crossbite. Treatment duration was defined as the time from initial aligner delivery to the completion of all refinement stages. Multivariable linear regression analysis was performed to evaluate the associations between pretreatment characteristics and treatment duration. Internal validation was performed using bootstrap resampling (5000 iterations).
Results
The 11 pretreatment variables collectively explained 32.8% of the variability in treatment duration (R2 = 0.328; adjusted R2 = 0.302). Overbite showed the strongest association with treatment duration, followed by mandibular crowding, midline deviation, and posterior crossbite (P <0.001). Each 1 mm increase in overbite and overjet was associated with increases of approximately 41 and 15 days in treatment duration, respectively. The presence of posterior crossbite was associated with an approximately 89-day increase. Bootstrap analysis demonstrated the stability of the regression estimates.
Conclusions
Pretreatment dentoalveolar characteristics were significantly associated with treatment duration in nonextraction CAT. Although several baseline characteristics independently contributed to treatment duration, the model explained approximately one-third of its variability, highlighting the influence of biological, behavioral, and treatment-related factors beyond pretreatment records.
The findings can help clinicians better understand the planning of space opening for PMLIs before clear aligner therapy commences and provide baseline information for future research.
Maurice J Meade, Yannii Pouferis, T. Weir· American Journal of Orthodon...· 0 citations
The purpose of this study was to evaluate the predictability of tooth movements achieved with Invisalign® clear aligners and to compare the efficiency of two different types of attachments (conventional vs optimized) for rotational and extrusive movements on the upper dentition. Four hundred forty-seven upper teeth from 61 patients were evaluated. Pre- and post-treatment models were superimposed on the entire maxillary model using the 3D Slicer platform and the iterative closest point algorithm. Extrusion and labial crown inclination of upper incisors, rotation of upper canines and premolars, and expansion of the first molars and premolars were assessed and compared with the tooth movement table of the ClinCheck® virtual treatment plan. The overall predictability of movements across all attachment types was 29.5% for extrusion, 33% for labial crown inclination, 70% for rotation, and 86% for expansion. The median predictability of all movements was 65.55%. Central incisors achieved greater extrusion than lateral incisors (p = 0.011), whereas laterals demonstrated greater labial crown inclination relative to predicted values (p = 0.023). Premolars showed a greater predictability of movement between achieved and predicted rotation than canines (p < 0.001). Conventional attachments achieved 1.95° more rotation than optimized attachments (p = 0.002). While the predictability for expansion and rotational movements was satisfactory, it was less accurate for extrusion and labial crown inclination. Optimized attachments were as efficient as conventional ones for extrusive movements, but rotational movements showed better efficiency with conventional attachments.
Unknown authors· Digital and Aligner Orthodon...· 0 citations
The achieved rotation of maxillary canines after the wear of an initial series of Invisalign aligners differed from the planned movements in both magnitude and direction for planned rotations of ≥5°.
Hannah Chong, T. Weir, Maurice J Meade· American Journal of Orthodon...· 0 citations
Vision therapy (VT) has been proposed as a nonsurgical treatment option for intermittent exotropia (IXT), although evidence regarding the optimal treatment dosage remains limited. This study aims to investigate the relationships between VT dosage and baseline demographic and clinical characteristics of treatment outcomes in IXT. Patients with IXT who underwent office-based VT between July 2020 and March 2024 at Changsha Aier Eye Hospital were included. Treatment outcome was classified as functional recovery (yes/no), defined by prespecified thresholds for fusion on the Worth Dot test (33 cm, 1 m, and 3 m), stereoacuity (distance and near), and convergence amplitudes. Binary logistic regression was used to evaluate associations between baseline characteristics and VT dosage on treatment outcomes. The Benjamini–Hochberg procedure was used to adjust P values and maintain the false discovery rate at 5%. Among 636 patients, 296 (46.5%) achieved functional recovery (38.5% in the ten-session group, 46.5% in the 20-session group, and 52.9% in the ≥ 30-session group). After adjustment for baseline fusion status, stereoacuity, and convergence amplitudes, each additional ten VT sessions was associated with a 5% increase in the odds of functional recovery (odds ratio, OR = 1.05, 95% CI 1.02–1.07; P = 0.003). Patients with better baseline Worth Dot fusion at 3 m were more likely to meet recovery criteria (OR = 1.28 per 1-point increase, 95% CI 1.12–1.48; P < 0.001). Moreover, worse baseline stereoacuity at near (OR = 0.43 per 1-log10 arcsec increase, 95% CI 0.30–0.62; P < 0.001) and far (OR = 0.12 per 1-log10 arcsec increase, 95% CI 0.06–0.23; P < 0.001) were associated with a reduced likelihood of functional recovery. Age, gender, treatment frequency, baseline Worth Dot at 33 cm or 1 m, and baseline convergence amplitudes were not associated with outcomes. Significant improvements were observed for nearly all measured clinical parameters. Office-based VT was associated with functional recovery in patients with IXT, with greater gains in those who received more therapy sessions and had better baseline binocular function. Prospective, randomized trials are needed to confirm these findings.
Xinyuan Pan, Ziang Yin, Huina Zhang et al.· Ophthalmology and Therapy· 0 citations
BACKGROUND
Clear aligner treatment (CAT) may induce masticatory muscle tenderness and trigger temporomandibular disorders (TMD). Considering that CAT may interfere with the masticatory system, it is important to understand the relationship between CAT and occlusal changes.
OBJECTIVES
This study aimed to analyze occlusal changes during CAT and assess the influence of postorthodontic occlusion on masticatory performance. A secondary objective was to determine whether the case complexity, the facial biotype and malocclusion were associated with occlusal alterations, masticatory performance, or the onset of TMD signs and symptoms during CAT.
MATERIAL AND METHODS
Forty-two individuals who underwent and completed CAT were evaluated at 3 time points: before treatment (T0); at the end of treatment (T1); and 3 months after treatment, during which time clear aligners (CAs) were used only at night (T2). Temporomandibular disorders were assessed using Axis I of the Diagnostic Criteria for Temporomandibular Disorders (DC/TMD) at T0, T1 and T2. Masticatory performance was evaluated at T1 and T2 using a two-colored chewing gum test and colorimetric analysis. Occlusal area and anterior and posterior occlusal contacts were evaluated digitally. Non-parametric statistical tests were used, with the significance level set at p < 0.05.
RESULTS
The occlusal area decreased significantly from T0 to T1 (p = 0.016). At T1, normodivergent individuals had significantly more anterior contacts than hyperdivergent patients (p = 0.013). Masticatory performance increased with the number of posterior occlusal contacts (p < 0.05), and individuals with Class I molar relationship had more anterior contacts than Class II patients (p = 0.004). At T2, Class III individuals showed higher values than Class II patients (p = 0.011).
CONCLUSIONS
The number of occlusal contacts and occlusal contact area decreased during treatment. Nighttime use of CAs slightly enhanced occlusal contact recovery. Complex cases presented more posterior contacts at T0; simple cases presented a greater occlusal area at the end of CAT. Class I individuals presented more anterior contacts at T0. These movements increased the anterior contacts in Class III molar cases at the end of treatment and 3 months later. No significant differences in masticatory performance were found according to the molar relationship, the facial biotype or the case complexity; no TMD signs and symptoms were found during or after CAT.
Vanessa Marcelino, J. C. H. Fernandes, Maria dos Prazeres Gonçalves et al.· Dental and Medical Problems· 0 citations
OBJECTIVE
To assess the impact of baseline malocclusion severity on the number of prescribed, used aligners and treatment duration.
MATERIALS AND METHODS
An unrestricted, independent search was conducted on the Invisalign ClinCheck database of a private practice for patients without any missing anterior teeth and whose treatment was finished between April 2021 and December 2024. Descriptive statistics were generated, and the feature selection Boruta algorithm (random forest algorithm) was implemented to identify important predictors for the number of aligners (prescribed, used) and treatment duration.
RESULTS
A total of 404 patients were included (age: 29.57 [10.7] years). Mean numbers of prescribed, used and unused aligners were 72.21 (37.52), 65.63 (30.40) and 6.57 (14.09), respectively. Important predictors of the numbers of the prescribed and used aligners were relatively similar and included molar and canine relationships, maxillary crowding, overjet, presence and number of missing or extracted posterior teeth, overbite, presence and number of teeth in posterior crossbite and midline discrepancies. Treatment duration was associated with baseline maxillary crowding, molar and canine relationships, overjet, overbite, midline discrepancies and the presence and number of missing or extracted posterior teeth.
CONCLUSIONS
Factors related to the baseline malocclusion severity significantly affect the number of prescribed, used aligners and treatment duration. This information could be used for informed practice and patient communication, including future evaluation of the biological and environmental footprint of aligners.
A. Gkinosati, Candice Durgnat, Effimia Koumpia et al.· Orthodontics & craniofacial...· 0 citations
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