Clinical efficacy of the Invisalign mandibular advancement appliance: A retrospective investigation

Clinical Efficacy of Nasoalveolar Moulding Using Aligner NAM During Presurgical Infant Orthopaedics (PSIO) in Infants With Unilateral Cleft Lip and Palate (UCLP): A Retrospective Study

OBJECTIVE

The study compares and evaluates planned virtual outcomes with actual post-treatment outcomes to assess the accuracy and predictability of clinical results during presurgical infant orthopaedics (PSIO) with AlignerNAM in infants with unilateral cleft lip and palate.

SETTING

Institutional study.

PARTICIPANTS

14 UCLP patients.

MATERIALS AND METHODS

Digital models for infants with unilateral cleft lip and palate (UCLP) who had undergone PSIO with AlignerNAM between 1 and 6 weeks were obtained at three stages-pretreatment (To), planned (Tp) and post-treatment (T1). Linear and angular measurements were made on these using the OrthoAnalyser software (3Shape, Copenhagen, Denmark). A paired t-test and Bland-Altman analysis assessed the accuracy between predicted and achieved movements, while inter- and intra-rater reliabilities were also calculated using digital records of seven patients.

RESULTS

The study found no significant difference (p > 0.05) between the clinical outcome (post-treatment) values and the predicted values (obtained from the virtual post-treatment simulation/planned movement). The sagittal reduction in the cleft defect demonstrated the highest accuracy (97.71%), followed by the transverse reduction (95.1%). Overall, linear measurements achieved an accuracy of 94.57% and angular measurements an accuracy of 93.64%. All measurements were within the limits of agreement based on the Bland-Altman plots. The widths of limits of agreement were narrow and similar for both linear and angular measurements showing high levels of agreement.

CONCLUSION

AlignerNAM showed high accuracy in reducing cleft size and aligning alveolar segments in UCLP patients, achieving accuracy rates above 90% in both linear and angular dimensions. AlignerNAM appliance is a suitable alternative to conventional PSIO techniques.

A comparative analysis of soft tissue volumetric alterations utilizing root mean square and positive and negative average calculations through two software

OBJECTIVES

Clinicians and researchers analyze standard tessellation language (STL) files to assess soft tissue volumetric changes over time. Various software programs are available for this purpose. This study aimed to compare the root mean square (RMS), the average of positive deviations (AVG(+)), and the average of negative deviations (AVG(-)) obtained from metrology-grade and nonmetrology-grade software at the shortest and normalized distances when conducting a 3D comparison of a region of interest using multiple scans of the same patient over time.

METHODS

Forty-five intraoral scans from 11 patients who underwent soft tissue augmentation procedures were used to evaluate RMS, AVG(+), and AVG(-) at both the shortest and normalized distances using metrology-grade (Geomagic Control X, 3D Systems) and nonmetrology-grade (Medit Design, Medit Link) software programs. All scans of each patient were first aligned and combined into a single STL file using proprietary dental software. The region of interest, where the soft tissue procedure was performed, was then isolated, and the combined file was separated into individual scans for further comparison. Each aligned and cut scan was then compared with the others to assess RMS, AVG(+) and AVG(-) at the shortest and normalized distances using Geomagic Control X and Medit Design. A total of 344 previously aligned and cut scans were compared, resulting in 86 deviation measurements for each software and measurement mode. After assessing normality and homoscedasticity using the Shapiro-Wilk and Levene's tests, respectively, a two-way analysis of variance was performed to determine significant differences in RMS, AVG(+), and AVG(-), considering the software (Geomagic Control X and Medit Design) and measurement mode (shortest and normalized). Pearson correlation and R-squared values were also calculated for each software's RMS, AVG(+), and AVG(-). Statistical significance was set at 0.05.

RESULTS

The RMS and AVG(+) measurements calculated using Medit Design were statistically greater than those obtained with Geomagic Control X at both the shortest and normalized distances (p < 0.001). No statistically significant differences were observed when comparing AVG(-) (p > 0.05). A significant correlation was observed between the RMS (R = 0.804; p < 0.001), AVG(+) (R = 0.833; p < 0.001), and AVG(-) obtained (R = 0.613; p < 0.001), obtained with Geomagic Control X and Medit Design.

CONCLUSIONS

Significant differences were observed when comparing deviations of different scans of the same patient over time, using RMS and AVG(+) at both shortest and normalized distances with metrology-grade (Geomagic Control X) and non-metrology-grade software (Medit Design). No statistically significant differences were found in AVG(-).RMS and AVG(+) demonstrated a very strong correlation between Medit Design and Geomagic Control X, along with a strong correlation in AVG(-).

CLINICAL SIGNIFICANCE

The RMS, AVG(+), and AVG(-) deviations obtained from Geomagic Control X and Medit Design cannot be directly compared, as each software employs its own algorithm. Caution is necessary when interpreting RMS, AVG(+), and AVG(-) measurements reported in the dental literature.

Orthodontic Management of Class II Malocclusion with Clear Aligners: Mandibular Advancement vs. Class II Elastics

Background: This cephalometric study aimed to evaluate the effects of clear aligner therapy in growing individuals with Class II malocclusion, comparing two functional approaches: the use of Class II elastics or the Mandibular Advancement (MA). Methods: Cephalometric data from 39 patients with Class II malocclusion treated using clear aligners either combined with Class II elastics (EL group; n = 18) or Mandibular Advancement (MA group; n = 21) were analyzed and compared with an untreated control group (UC2; n = 15). Results: Both treatment groups (EL and MA) showed a significant reduction in the ANB angle compared to the control (MA: -1.5°; EL: -2.2°; UC2: +0.2°). An increase in mandibular length, as measured by Co-Gn, was observed in both the EL and MA groups (+5.5 mm and +8.3 mm, respectively) relative to the control group. Soft tissue analysis of the Pg-TVL distance from T1 to T2 revealed the most substantial forward displacement of the chin in the MA group (MA: +2.0 ± 3.7 mm; EL: +0.5 ± 0.7 mm; UC2: -1.6 ± 3.3 mm). Vertically, the MA group exhibited a more marked decrease in the palatal-mandibular plane angle than the other groups. Both treatment modalities significantly reduced overjet and overbite from T1 to T2. Conclusions: The EL and MA appliances effectively advanced the mandible, leading to significant improvements in the sagittal relationship, overjet, and overbite while maintaining stable vertical control. Additionally, the MA group exhibited a more pronounced forward movement of the soft tissue chin.

Assessment of linear and angular positions of central incisors in the maxilla and mandible related to planned overbite changes with clear aligner therapy

INTRODUCTION

The study aimed to determine how the achieved labiolingual movements of central incisors compared with those planned in patients treated with the Invisalign (Align Technology, San Jose, Calif) appliance and requiring differing amounts of overbite correction.

METHODS

Adults treated with Invisalign aligners and satisfying selection criteria were chosen from a large database. Pretreatment, planned, and achieved arch depth/linear changes and angular changes of the maxillary and mandibular central incisors were calculated from relevant stereolithography files within Align Technology's treatment planning Web-based software application via metrology software and illustrated via Bland-Altman plots. Pretreatment, planned, and achieved incisor apices positions were calculated.

RESULTS

A total of 232 patients were evaluated. Achieved arch depth/linear changes did not differ significantly (P ≥0.17) from those planned, whereas all achieved angular changes differed significantly (P ≤0.01) from those planned. The mean accuracy of planned arch depth/linear changes ranged 99.2%-100.5%, and the mean accuracy of planned angular changes ranged 57.0%-90.3%. Bland-Altman plots showed that differences between planned and achieved angular changes increased as planned overbite correction increased. Changes in central incisor apical positions were related to changes in root angulation.

CONCLUSIONS

Although achieved arch depth/linear changes were close to those planned with the Invisalign appliance, angular changes differed significantly from those planned pretreatment. Central incisor root apices moved more labially than planned as planned changes to overbite increased, with a corresponding potential increased risk of alveolar bony dehiscence and fenestration.

Evaluation of Facial Aesthetic Changes in Growing Class II Patients Treated with Herbst or Elastodontics: A Retrospective Study

Objective: The objective of this study was to evaluate the facial profile changes of patients treated for class II skeletal malocclusions with an elastodontic appliance compared to those treated with the Herbst appliance and a control group. Methods: Forty class II patients were treated using an elastodontic appliance (Group EA) and were compared to 40 patients treated with the Herbst appliance (Group H) and to 40 untreated class II children (Group C). Aesthetic profile variables were analysed using Arnett's analysis. Cephalograms were compared pre-treatment (T0) and post-treatment (T1). The Wilcoxon signed-rank test or paired-samples t-test was used for pairwise comparison of cephalometric measurements taken at T0 and T1. One-way ANOVA and Tukey's post hoc test were performed to assess differences between the groups. Results: In the elastodontic group, the inclination of the upper incisors increased by 4.05°. In addition, the Pog-TVL and B-TVL distances decreased by 2.84 mm and 1.79 mm, respectively. In patients treated with an elastodontic appliance, the inclination of the upper incisors increased by 4.05°. In addition, the Pog-TVL and B-TVL distances decreased by 2.84 mm and 1.79 mm, respectively. In patients treated with the Herbst appliance, the inclination of the lower incisors increased by 6.11°. Furthermore, the treatment resulted in reductions in the Pog-TVL distance (2.58 mm), the B-TVL distance (2.26 mm), and the LL-TVL distance (2.31 mm). Conclusions: The profile changes achieved by both devices are favourable for correcting class II skeletal malocclusion.

Deep overbite reduction in adolescent patients treated with Invisalign: A retrospective analysis

INTRODUCTION

Data regarding the efficacy of deep overbite correction with clear aligner therapy in adolescent patients are lacking. This study aimed to investigate the efficacy of deep overbite reduction in adolescent patients treated with Invisalign (Align Technology, San Jose, Calif) aligners.

METHODS

This retrospective study investigated a sample of 102 patients aged 10-17 years from a large database. All patients had completed wear of a prescribed series of Invisalign aligners with planned overbite reduction on a nonextraction basis. The predicted, pretreatment, and posttreatment overbite measurement values were obtained from Align Technology's ClinCheck digital facility. Linear modeling, with Bland-Altman plots, was used to compare the effect of age, the use of bite ramps, and the adoption of the eighth-generational (G8) protocol on the difference between predicted and achieved overbite measurements.

RESULTS

A total of 102 patients with a mean ± standard deviation age of 13.94 ± 1.53 years satisfied the selection criteria. A mean ± standard deviation of 41.38 ± 30.43% of the predicted overbite reduction was achieved. There were no differences in the predictability of overbite reduction between patients who were aged <14 years or those aged 14-17 years (P = 0.73), between patients prescribed and not prescribed bite ramps (P = 0.25), or between patients prescribed the G8 protocol and not prescribed the G8 protocol (P = 0.65).

CONCLUSIONS

The average achieved overbite was less than half of what was planned by the orthodontists via the ClinCheck facility. The age grouping, the provision of bite ramps, and the G8 protocol appear to have little influence on the efficacy of overbite reduction in adolescent patients.

Biomechanical effects of different mandibular movements and torque compensations during mandibular advancement with clear aligners: a finite element analysis

Introduction

This study aimed to evaluate the biomechanical effects of different mandibular movements and torque compensations during mandibular advancement with clear aligners using finite element analysis.

Methods

Models were constructed to include the mandible, teeth, periodontal ligament (PDL), and clear aligners with buccal wings. Five oral muscles (superficial masseter, deep masseter, medial temporalis, posterior temporalis, and medial pterygoid) were represented as springs. Muscle values were measured and applied during different mandibular movements, including advancement distances (1-7 mm) and occlusal opening distances (2-4 mm). Different torque compensation angles (0°, 1°, 2°, and 3°) were applied to the mandibular central incisor.

Results

When the mandibular advancement was equal to or slightly excessed the occlusal opening distance, stress on the posterior PDL decreased and became more evenly distributed. Increasing the occlusal opening distance significantly raised stress on the posterior PDL and caused grater labial inclination of the mandibular anterior teeth. As the torque compensation increased, the labial inclination of the mandibular central incisor decreased, but stress on the PDL increased. Nearly complete bodily movement of the lower central incisor was achieved with torque compensation angles of approximately 15°, 19°, and 20° in models M1-2, M2-3, and M3-4, respectively.

Conclusion

To maintain periodontal health during mandibular advancement, it is recommended that the mandibular advancement distance be equal to or slightly excessed the occlusal opening distance. Excessive occlusal opening distance increases stress on the posterior PDL and the labial inclination of mandibular anterior teeth, requiring careful control. Additionally, proper torque control of the mandibular interior teeth is crucial for optimal outcomes.

Analysis of predicted and achieved root angulation changes in teeth adjacent to maxillary premolar extraction sites in patients treated with the Invisalign appliance

INTRODUCTION

This study aimed to investigate the expression of root angulation in canine, premolar, and first molar teeth adjacent to first and second premolar extraction sites in the maxilla after treatment with an initial series of Invisalign aligners (Align Technology, Santa Clara, Calif).

METHODS

Adult patients (aged ≥18 years) with at least 1 first and/or second premolar extraction in the maxilla and satisfying strict selection criteria were evaluated. Digital models representing pretreatment, predicted, and posttreatment were obtained from Align Technology's digital interface, ClinCheck. The Geomagic Control X (version 2017.0.3; 3D systems, Rock Hill, NC) software facility was used to determine and compare the root angulation of adjacent canine, premolar, and first molar teeth at different time points.

RESULTS

The predicted angulation of teeth was significantly different (P <0.02) than that achieved in most patients. When adjacent teeth roots were planned to tip away from the extraction site, there was an overexpression of the movement. When teeth roots were planned to tip into the extraction site, underexpression occurred, and movement was in the opposite direction in some instances. There was no difference in root angulation outcomes according to the prescribed number of aligners, 1- or 2-week wear protocols, and sex (P >0.05). Attachments were influential in controlling angulation in first-premolar extractions (P = 0.05), but optimized attachments were not any more effective than conventional attachments (P >0.05).

CONCLUSIONS

The achieved root angulation in teeth adjacent to premolar extraction sites in the maxilla after treatment with an initial series of Invisalign aligners differed significantly from that predicted. Attachments play a minor role in the predictability of root angulation outcomes.

Effects of clear aligners and traditional removable appliances on oral microbiome in mixed dentition: a comparative study

BACKGROUND

This prospective study aims to investigate the comparative effects of clear aligners (CA) and traditional removable appliances (RA) on the cariogenic risk of patients in mixed dentition, focusing on the oral microbiome.

METHODS

25 children were included and assigned into CA and RA groups. Supragingival plaque and saliva samples were collected, and clinical parameters including Decay-missing-filled teeth index (DMFT), Plaque Index (PI) and Gorelick Index (GI) were recorded before treatment (T0) and after 6-month follow-up (T1). DNA was extracted from supragingival plaque and saliva and analyzed via 16S rDNA gene sequencing.

RESULTS

Clinical parameters showed no statistically significant difference between groups at each time point or within group over time (p > 0.05). In both RA and CA groups, saliva exhibited significantly higher alpha diversity compared to supragingival plaque at T1, as indicated by the significantly higher Chao1 and Shannon indexes (p < 0.05). Regarding beta diversity, significant difference was observed in saliva and supragingival plaque samples between T0 and T1 within group RA (p < 0.05, Adonis), whereas no such significance was noted in the CA group (p > 0.05, Adonis). At the genus level, Lactobacillus exhibited a statistically significant increase in saliva and supragingival plaque of group RA from T0 to T1 (p < 0.05), and an increasing trend in the group CA without statistical significance (p > 0.05). At T1, Lactobacillus levels were comparable between groups, whereas species-level analysis revealed distinct cariogenic species.

CONCLUSION

Both clear aligners and traditional removable appliances resulted in elevated cariogenic risk of patients in mixed dentition at the microbial level. Distinct alterations in cariogenic species were observed to be induced by various orthodontic appliances.

Planned and achieved overjet and overbite changes following an initial series of Invisalign® aligners: A retrospective study of adolescent patients

OBJECTIVE

The aim of the present study was to compare the changes in overjet and overbite measurements achieved in adolescent patients following an initial series of Invisalign® aligners (Align Technology, San Jose, California) with those planned by orthodontists via its ClinCheck® digital treatment planning facility.

METHODS

Data provided by Align regarding patients who had completed an initial series of Invisalign® aligner treatment and were less than 18-years old were assessed in relation to pre-treatment, planned and achieved overjet and overbite measurements. Descriptive statistics, Wilcoxon rank-sum, Mann Whitney calculations were computed.

RESULTS

A total of 290 patients satisfied inclusion criteria. The median (interquartile range (IQR)) age was 14.17 (13,15.42) years. The median achieved overjet and overbite changes were less than those planned (p<0.01) with 53.33% of the planned median overjet increase achieved and 52.94% of planned median overjet reduction achieved. Additionally, 58.33% of the planned median overbite increase was achieved and 55.55% of the planned median overbite reduction was achieved. A total of 21.52% patients recorded no change or an increase from pre-treatment to the achieved overjet where reduction was planned, whereas 41.67% recorded no change or a reduction in overjet where increase was planned. A total of 18.72% recorded no change or an increase in overbite where reduction was planned, whereas 20.75% recorded no change or a reduction in overbite where increase was planned.

CONCLUSIONS

Less than 60% of the planned overjet and overbite changes per patient were achieved. Between 18.72 and 41.67% of patients experienced no change or changes in overjet and overbite in the opposite direction to that planned. This is likely to be clinically significant.