Upper arch dimensional changes with clear aligners in the early mixed dentition : A prospective study

Predictability of expansion movements performed by clear aligners in mixed dentition in both arches: a retrospective study on digital casts

BACKGROUND

to evaluate the predictability of expansion achieved in patients in early mixed dentition treated with Clear Aligners (CA), analyzing the efficiency of the expansion at the end of the first set of aligners and at the end of the therapy in the upper and lower arch.

METHODS

36 patients (20 F, 16 M; mean age 8.3 ± 1.5 years) were selected retrospectively from the Department of Orthodontics of the Hospital of Rome "Tor Vergata". All subjects were treated with CA with no other auxiliaries than attachments. For each patient a standardized sequential expansion protocol was planned for both arches. Digital dental casts were created at three observation periods from an intraoral scanner: prior to treatment (T0), at the end of the first set of aligners (T1), at the end of treatment (T2). The 3D models in planned position determined by the first Clincheck (CC) were obtained for comparison with T1 and T2. Six linear transversal measurements were used to evaluate the dimensional changes and the predictability of expansion movements, comparing T1-CC and T2-CC.

RESULTS

a statistically significant increase within the pre-treatment and the final outcomes for all the variables examined was found. In the upper arch, the greatest level of predictability was detected at the level of the first (46.44%) and second deciduous molar width (44.95%) at T1. The analysis of T2-CC changes showed a significant increase in the percentage of predictability of expansion at the level of the first permanent molars, at mesial (54.86%) and distal (58.92%) width. In the lower arch, a higher percentage of predictability than the upper arch was reported at T1-CC and T2-CC, with the greatest values at the level of second (T1-CC: 48.70%; T2-CC: 75.32%) and first deciduous molar width (T1-CC: 45.71%; T2-CC: 72.75%).

CONCLUSIONS

CA can induce significant transversal increments. The predictability of expansion is variable, but it did not exceed the 50% during the first set of aligners. It was necessary to apply refinement set to achieve a good predictability for expansion of about 70%. The expansion in the lower arch was observed to be more predictable than in the upper arch.

Clear Aligners in Pediatric Dentistry: A Scoping Review

Today not just adults but also children are affected by their looks and appearance. Their facial and dental appearance primarily influence how they present themselves in the outside world. Poor esthetic appearance at any age, especially when it comes to children, affects their psychological status. In earlier times, correction of dentition used to be done with crude methods, after which came the concept of braces, which were fixed on the labial surfaces. Even with these, the patients are equally concerned with their looks throughout the treatment, and thus neither adults nor children are eager to use the standard metallic-looking orthodontic gear. To tackle this problem, researchers have developed several solutions, and clear aligners are the modern and aesthetic answer. For effective tooth movement into the desired position, thin, transparent, plastic aligners known as invisible aligners are used, which are created using the computer-aided design/computer-aided manufacturing (CAD-CAM) technology. These aligners are analogous to the splints that cover the clinical crowns as well as the marginal gingiva. The treatment requires proper patient motivation as there can be poor compliance by patients. However, it can offer greater dental hygiene, comfort, and an excellent aesthetic experience during treatment. This review highlights the history of fabrication of clear aligners, examining the efficacy, advantages, and disadvantages of transparent aligners for pediatric patients and also dentists. It weighs aspects like aesthetic appeal, comfort, oral hygiene, treatment predictability, and practice efficiency when comparing transparent aligners, like Invisalign, to conventional orthodontic treatments. It also ascertains the applicability and worth of clear aligners in contemporary orthodontic practice, while examining patient happiness, compliance, and overall treatment results.

Cigarette smoke and tobacco heating aerosol on the aging of clear aligners

BACKGROUND

The treatments with clear aligners (CA) showed an exponential higher percentage in the last years being almost invisible with major patient acceptability and a resulting improvement in quality of life. CA are composed of thermoplastic polyurethane not inert but subjected to changes due to heating and humidity, chewing forces, and prolonged exposure to enzymes in saliva in the oral cavity and external factors. Cigarette smoke (CS) and the aerosol produced by tobacco products with reduced health risks may be considered among the external factors affecting CA. The purpose of this study was the assessment of optical properties (absorbance and transmittance) and roughness of CA after in vitro aging due to exposition to CS and THS2.2, compared to controls. The secondary objective will be the investigation of CS and THS2.2 effects on resin composite inside aligners used for attachments during treatment with CA.

METHODS

A total number of 60 CA units will be used and equally divided in three different groups (20 in each): CS group exposed to reference cigarettes smoking, THS2.2 group exposed to aerosol from 20 heat-not-burn sticks, and control group, CG to pure air only. The aligners will present ten introflection for the attachments on the anterior part. In accordance with ISO standard 3402, 3R4F cigarettes and THS2.2 tobacco sticks must undergo conditioning for a minimum of 48 hours and a maximum of 21 days at a temperature of 22±1 °C and a relative humidity of 60±3%.

RESULTS

Using spectrophotometry, the optical characteristics (absorbance and transmittance) of each aligner will be evaluated after aging (Jasco UV-vis V630PC, Tokyo, Japan). Each aligner will be cut with a rotating saw from canine to canine prior to the measurements in order to lop off the lingual region and displaying the labial barrier. The absorbance and transmittance measurements will be collected and statistically analyzed with a significance of P<0.05.

CONCLUSIONS

Surface roughness of the aligners and attachments inside them will be assessed by 3D scanning microscopy (Infinite Focus G4h). Color of resin composite will be assessed using the (CIE Lab) Commission Internationale de l'Eclairage L*a*b* color space by means of Olympus CrystalEyef dental spectrophotometer. Clinicians should advise patients to refrain from smoking and drinking coffee or tea while wearing aligners for two reasons: first, the color change is unacceptably noticeable when wearing aligners, and second, the material's chemical composition may be slightly altered, which could affect the intended dental movements.

Clear Aligners in the Growing Patient: A Systematic Review

Mixed dentition represents a critical phase in the oral development of pediatric patients, characterized by the simultaneous presence of primary and permanent teeth. This article proposes a comprehensive systematic review of the application of aligners as an innovative methodology in managing mixed dentition. The primary objective is to explore the efficacy, safety, and acceptability of this emerging orthodontic technology in the evolving age group. This systematic review focuses on randomized controlled trials, cohorts, and observational studies investigating the use of aligners in patients with mixed dentition. Clinical, radiographic, and psychosocial parameters will be considered to assess the overall impact of aligner therapy in this critical phase of dental development. An in-depth analysis of such data aims to provide a comprehensive overview of the potential of this technology in pediatric orthodontics. Expected outcomes may contribute to outlining practical guidelines and targeted therapeutic strategies for orthodontists involved in managing mixed dentition. Furthermore, this article aims to identify gaps in the current research and suggest future directions for studies exploring the use of transparent aligners in patients with mixed dentition, thereby contributing to the ongoing evolution of evidence-based orthodontic practices.

Comparison of Mechanical Behavior of Clear Aligner and Rapid Palatal Expander on Transverse Plane: An In Vitro Study

(1) Background: This study aims to investigate, within a controlled laboratory environment, the magnitude of the transversal load and the force decay over time produced by clear aligners in comparison to a Rapid Palatal Expander (RPE). (2) Methods: Resin models of a dental maxillary arch, additively manufactured from an intraoral scan, were inserted in a testing machine with uniaxial load cells to measure the force trend over time expressed by RPE and clear aligners. The mechanical load was recorded during a certain timeframe for both appliances. (3) Results: The force expressed by the RPE ranged from 30 to 50 N for each activation, decreasing with a nonlinear pattern over time. The force expressed by the clear aligner ranged from 3 to 5 N, decreasing with a linear pattern over time. In contrast, the force generated by the clear aligner fell within the range of 3 to 5 N, showing a linear reduction in force magnitude over the observed period of time. (4) Conclusions: The RPE exerted a force magnitude approximately ten times greater than that generated by clear aligners. Nevertheless, it is essential to acknowledge that the oral environment can significantly influence these results. These limitations underscore the need for caution when applying these findings to clinical settings.

Vertical effects of distalization protocol with Clear aligners in Class II patients: a prospective study

BACKGROUND

The aim of the present prospective study was to detect the effects on vertical dentoskeletal dimension produced by molar distalization with Clear Aligners in a group of subjects with Class II malocclusion.

METHODS

The Clear Aligners Group (CAG) comprised 20 patients (13 females, seven males) with a mean age of 17.2±3.2 years. The same standardized protocol of sequential distalization was applied in all subjects. For each patient lateral cephalograms have been analyzed before treatment (T1) and at the end of the therapy (T2).

RESULTS

At the end of treatment, clear aligners were effective in the correction of Class II dental relationship with the correction of the overjet (-1.3 mm). The treated group showed statistically significant reduction in FMA angle (-1.3°) associated with a counterclockwise rotation of the occlusal plane (POccl^PF -3.1°; SN^POccl -4.2°) and a slight intrusion of maxillary first molars to palatal plane (-0.9 mm). Finally, statistically significant differences were detected in anterior facial height (N-Me) and in the ArGo^GoMe angle (-1.2 mm and -3.4°, respectively).

CONCLUSIONS

Upper molar distalization with clear aligners represents a valid alternative to non-extraction treatment of Class II malocclusion, reducing the extrusion of maxillary first molars and improving the control of the occlusal plane and of the vertical dimension.

Treatment effects after maxillary expansion using invisalign first system vs. acrylic splint expander in mixed dentition: a prospective cohort study

BACKGROUND

Invisalign First System (First) is a new type of orthodontic appliance for maxillary arch expansion in mixed dentition children. Till now, few studies have evaluated the expansion effects of First versus other appliances. What's more, most studies of arch expansion did not include a natural group to rule out growth effects. This prospective cohort study aimed to evaluate the dental and dentoalveolar effects using First or acrylic splint rapid maxillary expander (RME) in adolescents excluding growth factors.

MATERIALS AND METHODS

After screening by strict inclusion criteria and propensity score matching (PSM), fifty-one patients were included: First group (n = 17), RME group (n = 17), and natural growth (NG) group (n = 17). Nine indicators including dental arch width, dentoalveolar arch width, and inclination of the molars were measured on digital dental casts at baseline (T0) and six-month follow-up (T1). Paired t-tests were used for intra-group results, and two-sample independent t-tests were used for inter-group comparisons.

RESULTS

There was no significant increase in all indicators within six months in the NG group (p > 0.05). In the First group and RME group, all width indicators were significantly increased after treatment (p < 0.05). The RME group exhibited greater expansion than the First group in intercanine width, first interpremolar width, second interdeciduous molar width, first intermolar width, arch perimeter, intercanine dentoalveolar width, intermolar dentoalveolar width, and inclination of the molars (p < 0.05). Whereas, there was no significant difference in arch depth between the two treated groups.

CONCLUSIONS

Both First and RME can expand the maxillary arch in mixed dentition. In case of mild to moderate maxillary transverse deficiency (MTD), Invisalign First System could be a reasonable option. RME shows significant better efficiency of dental arch expansion than First, recommended for patients with severe MTD.

TRIAL REGISTRATION

This prospective study was registered on ClinicalTrials.gov (01/02/2022, registration number: ChiCTR2200056220). The trial was approved by the Ethical Committee of the Hunan Xiangya Stomatological Hospital Central South University (20,200,088), and informed consent was obtained from all subjects and their legal guardian(s).

Is maxillary arch expansion with Invisalign® efficient and predictable? A systematic review

BACKGROUND

The main objective of this review is to assess the effectiveness and predictability of the transverse expansion movement performed by Invisalign®. The secondary objectives are to determine whether the expansion is of a dentoalveolar or skeletal nature, and to locate the areas of expansion on the dental arch.

METHODS

Two investigators used the PubMed database to search for articles related to the subject. After using a research equation, specific inclusion and exclusion criteria were applied and the final selection of articles was done after being read in full. The ROBINS-I tool for non-randomized studies was applied to assess risk of bias in the results of each included study.

RESULTS

After reading the articles in full, 12 articles were included. Regarding effectiveness, most studies showed an increase in all measured interdental distances, with a maximum expansion at the premolar level. As for predictability, significant differences were found between post-treatment models and Clincheck® models, making it generally weak. Concerning the nature and areas of expansion, increase of arch width was due to buccal tipping of the crowns following a decreasing gradient from anterior to posterior.

CONCLUSIONS

Invisalign® treatment is effective in achieving a maxillary transverse expansion. However, this expansion is mainly dentoalveolar, with a facial crown tipping of the posterior teeth. Clincheck® software tends to overestimate the expansion movement when compared to the clinical outcome, therefore the predictability of movement is low.

Predictability and Effectiveness of Nuvola® Aligners in Dentoalveolar Transverse Changes: A Retrospective Study

Nowadays, many people use clear aligners to address their dental issues. The efficacy of transparent dental aligners must be investigated even though they are more aesthetically pleasing, easy to use, and tidy than permanent tools. Thirty-five patients in this study's sample group who used Nuvola^® clear aligners for their orthodontic therapy were prospectively observed. Initial, simulated, and final digital scans were analysed with a digital calliper. The actual results were compared with the prescribed ending position to evaluate the efficacy of transversal dentoalveolar expansion. Aligner treatments in Groups A (12) and B (24), particularly in the dental tip measures, demonstrated high adherence to the prescription. On the other hand, the gingival measures exhibited a greater level of bias, and the differences were statistically significant. However, there was no difference in the outcomes between the two groups (12 vs. 24). Within specific parameters, the evaluated aligners were shown to be helpful in predicting movements in the transverse plane, particularly when considering movements linked to the vestibular-palatal inclination of the dental elements. This article compares the expansion effectiveness of Nuvola^® aligners compared with other work in the literature using competitor companies.

Dental Materials Design and Innovative Treatment Approach

In recent years, technological innovation has had exponential growth, resulting in positive implications in dentistry [...]

Clear aligner therapy in the mixed dentition: Indications and practitioner perspectives

INTRODUCTION

This study evaluated current trends and perspectives among orthodontists regarding clear aligner therapy in the mixed dentition (CAMD), including insights into perceived indications, compliance, oral hygiene, and other factors.

METHODS

An original, 22-item survey was mailed to a randomized, nationally representative sample of practicing orthodontists (n = 800) and a specific, randomized subsample of high-aligner-prescribing orthodontists (n = 200). Questions assessed respondents' demographic information, experience with clear aligner therapy, and perceived advantages and disadvantages of CAMD compared with fixed appliances (FAs). Responses were compared using McNemar's chi-square and paired t tests to assess CAMD vs FAs.

RESULTS

One thousand orthodontists were surveyed, and 181 (18.1%) responded over 12 weeks. CAMD use was less common than mixed dentition FAs, but most respondents predicted an increase in their future CAMD use (57.9%). Among respondents using CAMD, the number of patients with mixed dentition treated with clear aligners was significantly lower than the number of total patients with clear aligners (23.7% vs 43.8%; P <0.0001). Fewer respondents considered skeletal expansion, growth modification, sagittal correction, and habit cessation feasible indications for CAMD compared with FAs (P <0.0001). Perceived compliance was similar for CAMD and FAs (P = 0.5841), but perceived oral hygiene was significantly better with CAMD (P <0.0001).

CONCLUSIONS

CAMD is an increasingly common treatment modality for children. Most surveyed orthodontists reported limited indications for CAMD compared with FAs but perceived noticeable benefits for oral hygiene with CAMD.

Efficacy and Accuracy of Maxillary Arch Expansion with Clear Aligner Treatment

The aim of this work was to evaluate the efficacy and accuracy of maxillary arch transverse expansion using the Invisalign^® clear aligner system without auxiliaries other than Invisalign attachments. Knowing the accuracy of a movement through a clear aligner system allows the clinician to plan the treatment with greater precision and to achieve the expected result faster. The study group included 28 patients with a mean age of 17 ± 3.2 years. The treatment protocol for all the selected patients included the application of the Invisalign^® clear aligner system without auxiliaries, except for the Invisalign^® attachments; in no case were tooth extraction or interproximal enamel reduction (IPR) performed. Linear measurements of the expansion were assessed before treatment (T0), at the end of treatment (T1), and on final virtual models by ClinCheck^® (TC). A paired t-test was used to compare T0-T1 and T1-TC differences. A paired t-test was applied, and one normality was validated with the Shapiro-Wilks test. If normality was not met, the nonparametric test (Mann-Whitney U test) was applied. The level of significance was set at 5%. Statistically significant differences were found for all measurements at T0-T1. The results showed an average accuracy of efficacy of 70.88%. The differences in predictability between the various vestibular measurements (intercanine, inter-premolar, and intermolar) were not statistically significant, while they were for gingival measurements. The overall accuracy of the expansion treatment was 70%, regardless of tooth type.

Comparison between clear aligners and 2 × 4 mechanics in the mixed dentition: a randomized clinical trial

OBJECTIVES

To compare the efficacy and efficiency between clear aligners and 2 × 4 fixed appliances for correcting maxillary incisor position irregularities in the mixed dentition.

MATERIALS AND METHODS

The sample comprised 32 patients from 7 to 11 years of age randomly allocated into two parallel treatment groups: the clear aligners group, 14 patients (6 girls, 8 boys) with a mean initial age of 9.33 years (standard deviation [SD] = 1.01) treated with clear aligners; and the fixed appliances group, 13 patients (9 girls, 4 boys) with a mean initial age of 9.65 years (SD = 0.80) treated with partial (2 × 4) fixed appliances. Digital models were acquired before treatment and after appliance removal. Primary outcomes were incisor irregularity index and treatment time. Secondary outcomes were arch width, perimeter, length, size and shape, incisor leveling, incisor mesiodistal angulation, plaque index, and white spot lesion formation (International Caries Detection and Assessment System index). Intergroup comparisons were evaluated using t-tests or Mann-Whitney U-tests with Holm-Bonferroni correction (P < .05).

RESULTS

Treatment time was approximately 8 months in both groups. No intergroup differences were observed for changes in any of the variables. Similar posttreatment arch shapes were observed in both groups.

CONCLUSIONS

Clear aligners and 2 × 4 mechanics displayed similar efficacy and efficiency for maxillary incisor position corrections in the mixed dentition. The choice of appliance should be guided by clinician and family preference.

Gingival Margins' Modifications during Orthodontic Treatment with Invisalign First®: A Preliminary Study

The aim of the study was to assess modifications of gingival morphology at the end of Phase I treatment with Invisalign First. Eighteen subjects (ten females, eight males, mean age nine years) treated with Invisalign First were selected. The following parameters were measured on intraoral photographs before treatment (T0) and after the first set of aligners (T1) at level of permanent incisors, deciduous canines and molars: gingival margin height (GMH) and deciduous canine inclination (DCI). A paired t-test was used to evaluate T1-T0 changes. The level of significance was established at 5%. Deciduous canines' GMH showed a major reduction between T1 and T0 accounting for 0.87 mm and 0.86 mm, respectively on the right and left sides. DCI increased for all patients in the interval T0-T1 on both sides, +7.11° on the right and +7.5° on the left. Tooth movement during Invisalign First induced significant modifications of gingival contour resulting in a more harmonious smile.

Evaluation of the Upper Arch Morphological Changes after Two Different Protocols of Expansion in Early Mixed Dentition: Rapid Maxillary Expansion and Invisalign® First System

Background: The objective of this retrospective study was to analyze the morphological changes of the upper arch after two protocols of expansion, the Invisalign® First system and rapid maxillary expansion (RME), in mixed dentition by means of geometric morphometric analysis (GMM). Methods: Digital dental casts of 32 children treated either with RME (RME group: 17 subjects; mean age 8.1 years) or the First system (First group: subjects; mean age 8.4 years) were collected. For both the RG and FG, pre-(T1) and post-treatment(T2) digital models were created. A total of 14 landmarks were digitized and GMM was applied. Procrustes analysis and principal component analysis (PCA) were performed. Results: The PC1 resulting from the T2–T1 comparison in the RG g showed statistically significant morphological changes in the posterior region of the upper arch shape, without significant variations in the anterior region. The comparison of the T2–T1 changes in the FG showed an increase in the transverse dimension at the level of the canine and the first deciduous molar widths, with morphological variation in the anterior region due to frontal teeth alignment. Conclusions: The First system induced shape modifications of the upper arch during expansion in contrast to RME. The FG presented an improvement in the maxillary arch shape, while the RG maintained the initial triangular shape.