Predicted overbite and overjet changes with the Invisalign appliance: a validation study

Factors affecting expansion predictability of clear aligner treatment

OBJECTIVES

To determine the clinical factors associated with expansion predictability using clear aligners.

MATERIALS AND METHODS

Pretreatment, prediction in the first approved ClinCheck, and pretreatment of the first refinement digital casts were recovered from Invisalign's ClinCheck software for 98 patients with permanent dentition. Arch width measurements were collected in the ClinCheck arch width table for canines, first and second premolars, and first molars. Expansion predictability was calculated by subtracting the expansion achieved from that predicted. Expansion predictors were explored using univariate and multivariate generalized linear mixed models (GLMM).

RESULTS

Ninety-eight patients (mean age 48.7 years, standard deviation [SD] = 12.5 years) with 1440 eligible teeth (720 on each side) were assessed. The absolute difference between planned and achieved expansion was 0.92 mm (95% confidence interval [CI]: 0.86-0.99). While 72.2% of the measurements showed some degree of underexpansion, 79.3% of all overcorrections appeared in the mandible. According to the univariate analysis, the following variables were associated with expansion predictability: sex, arch, presence of posterior crossbite, absence of extractions, placement of attachments, absence of stripping, tooth type and higher predicted expansion. Those identified by GLMM were arch, tooth type, amount of predicted expansion and posterior crossbite.

CONCLUSIONS

Expansion with Invisalign aligners is more reliable in the lower jaw and in the canine region. Cases with large, planned expansions or initial posterior crossbites (unilateral or bilateral) seem less predictable.

CLINICAL RELEVANCE

The risk of not achieving the planned expansion is greater in the maxilla, posterior teeth, and when crossbite is present.

Prediction of overbite improvement in deep bite correction using clear aligner therapy

OBJECTIVES

This study aimed to determine the accuracy of overbite correction in patients with deep bite using the clear aligner therapy (CAT).

MATERIALS AND METHODS

This retrospective study included 31 patients prescribed orthodontic treatment using CAT from January 2020 to January 2024. Clinical information was collected via X-ray results at pre-treatment and post-treatment stages. Treatment outcomes were measured at three stages: pre-treatment, post-treatment (clinical results), and predict treatment (predict results) as programmed in ClinCheck®.

RESULTS

Significant changes were observed in X-ray in both overbite (3.85 ± 1.38 mm to 2.93 ± 1.13 mm) and overjet (5.19 ± 1.79 mm to 3.43 ± 1.14 mm) following CAT. For clinical crown lengthening (CCL) of tooth 31, significant differences were noted between pre-treatment and post-treatment (-0.31 ± 0.66 mm) and between predicted and clinical results (-0.21 ± 0.58 mm). For CCL of tooth 41, significant differences were found between pre-treatment and post-treatment (-0.36 ± 0.66 mm) and between prediction and post-treatment (-0.32 ± 0.65 mm). The percentage of deep bites differed significantly between pre-treatment vs predicted treatment (38.10 ± 14.90%), pre-treatment vs post-treatment (11.80 ± 14.30%), and predicted treatment vs post-treatment (-26.40 ± 12.60%). Similar trends were observed in mean overbite (2.77 ± 1.07 mm, 0.69 ± 0.93 mm, and - 2.08 ± 0.83 mm, respectively).

CONCLUSIONS

Our findings support the use of CAT as a reliable and aesthetic option for treating deep bite malocclusions.

Predictability of incisal labiolingual inclination, overjet, and overbite changes, and the prevalence of open gingival embrasures in patients with mandibular incisor extraction treated with Invisalign: A retrospective cohort study

INTRODUCTION

This retrospective study aimed to assess differences between the planned Invisalign (Align Technology, San Jose, Calif) ClinCheck tooth movements and the achieved outcomes for patients with single mandibular incisor extraction with respect to overjet, overbite, and labiolingual inclination for the initial series of aligners and to assess the prevalence of open gingival embrasures (OGEs) in the former extraction sites.

METHODS

The records of 83 patients who received Invisalign treatment with extraction of a single mandibular incisor were evaluated. The predicted and achieved overjet and overbite measurements were compared using the Invisalign ClinCheck software. The prevalence of an OGE was assessed visually using posttreatment digital models. The labiolingual inclination of the mandibular incisors was measured through superimposition of the pretreatment, predicted posttreatment, and achieved posttreatment digital models using Geomagic Control X (version 2018 1.0; 3D Systems, Rock Hill, SC) metrology software.

RESULTS

Differences between predicted and achieved labiolingual inclination changes of the mandibular incisors were minor in the lingual direction (90.4%); however, planned labial movements were significantly underexpressed (59.0%). A comparison of the predicted and achieved overjet values revealed a clinical expression of 49.6% and 76.0% when the overjet was planned to decrease and increase, respectively. With respect to the predicted and achieved overbite changes, no significant difference was found when the overbite was predicted to increase. In contrast, when the overbite was predicted to decrease, only 50.5% of this planned overbite reduction was clinically achieved. Most patients (95.2%) displayed an OGE in the former extraction space.

CONCLUSIONS

Extraction of a single mandibular incisor in conjunction with Invisalign treatment resulted in an underexpression of the predicted proclination of the mandibular incisors, overjet changes, and overbite reduction. The development of an OGE was highly probable after the initial CAT aligner series.

Teenage Patients with Class II Subdivision Treated with Aligners and Elastics: A Retrospective Study

Background and Objectives: This study aimed to evaluate the outcomes of Class II subdivision teenage patients treated with Invisalign® clear aligners (CAs) and elastics. Materials and Methods: A total of 23 individuals aged 14.3 ± 2.5 years were enrolled in this study. The participants were divided into Group 1 (mandibular midline deviation) and Group 2 (maxillary midline deviation). The midline deviation from the facial midline; anteroposterior discrepancy; overjet (OJ), overbite (OB), and Peer Assessment Rating (PAR) scores; upper incisor and lower incisor (L1) positions; and angulation were measured at the beginning (T0) and end (T1) of the orthodontic treatment. Results: Group 1 showed significant higher variations in OJ (-2.3 ± 2.3 vs. -0.6 ± 0.8, p < 0.001), OB (-2.1 ± 2.3 vs. -1.1 ± 1.4, p < 0.001), PAR score (-32.0 ± 11.7 vs. -27.3 ± 13.1, p < 0.001), L1-to-mandibular-plane angle (-3.6 ± 7.0 vs. -1.3 ± 3.2, p < 0.001), and interincisal angle (10.07 ± 8.7 vs. 5.9 ± 5.3, p = 0.007). The midline deviation was the only measurement with higher variation in Group 2. The average distance between the mesiobuccal cusp of the maxillary first molar and the buccal groove of the mandibular first molar was 0.3 ± 0.5 mm. Conclusions: A total of 21 patients achieved bilateral Class I (91% success rate) and demonstrated great improvement (72-96%) in PAR scores. Regardless of the etiology of malocclusion, the orthodontic correction of the Class II subdivision with CAs showed high accuracy and predictable results.

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.

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.

A Cross-Sectional Survey of the Use of Clear Aligners by General Dentists in Australia

OBJECTIVES

The primary aim of the investigation was to survey clear aligner therapy (CAT) use among general dentists in Australia. A secondary aim was to evaluate the factors that influenced general dentists in Australia not to provide CAT.

MATERIAL AND METHODS

General dentists registered with the Australian Health Practitioner Regulation Agency were invited to participate in a structured cross-sectional electronic survey. The survey covered demographics, preferred CAT systems and practices, relevant treatment planning and retention protocols, patient-reported CAT issues, pertinent respondent opinions, and reasons for not providing CAT. Descriptive statistics were computed via GraphPad Prism v10 (GraphPad Software Inc., La Jolla, CA, USA).

RESULTS

Most of the 264 (n = 172; 65.2%) respondents indicated that they provided CAT. The majority (n = 82; 58.6%) reported that they treated between 1 and 20 patients with CAT annually. Invisalign was the most used system (n = 83; 61.2%), with 55 (41.7%), indicating that they used more than one system. Most (n = 124; 98.4%) were comfortable using CAT for mild crowding, whereas 73.4% (n = 94) were not comfortable in treating severe crowding with CAT. The median (IQR) number of patients per respondent treated with extraction of a permanent incisor or premolar was 0 (0). Issues regarding tooth positions were reportedly always or mostly in need of change in the initial treatment plan by 68.7%. Problems regarding patient compliance with CAT wear protocols (n = 67; 45.6%) and the predictability of treatment outcomes (n = 31; 21.1%) were the most identified themes of the free-text comments. Over 80% of those who did not provide CAT indicated that they preferred to refer to an orthodontist for management.

CONCLUSION

Almost two-thirds of the respondents provided CAT. Invisalign was the most used system. The majority use CAT combined with nonextraction treatment. Most of those who did not provide CAT preferred to refer to an orthodontist for patient management.

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

INTRODUCTION

This retrospective investigation aimed to determine whether the achieved changes in the treatment of Class II malocclusion were the same as those planned after the prescribed wear of an initial phase of Invisalign treatment with the mandibular advancement appliance (MAA) (Align Technology, Santa Jose, Calif).

METHODS

All patients treated with the MAA and who satisfied inclusion/exclusion criteria were selected from a database of 16,500 patients treated with clear aligners by 16 orthodontists. The pretreatment, planned, and achieved overjet measurements were documented from data provided in Align Technology's software facility, ClinCheck. Changes in intermaxillary anteroposterior (AP) first permanent molar (FPM) relationships were evaluated using Geomagic Control X (3D systems, Rock Hill, SC) metrology software.

RESULTS

Most of the 195 patients who satisfied the inclusion criteria were females (n = 104; 53.3%). The mean age was 12.62 ± 2.20 years. The pretreatment overjet was reduced from 6.49 ± 2.86 mm to 4.61 ± 2.22 mm after prescribed MAA wear, which was 42.5% of the planned outcome. The pretreatment AP FPM reduced from 3.14 ± 1.95 mm to 2.24 ± 2.51 mm, which was 31.3% of that planned. Thirty-eight (19.5%) patients experienced an increase in overjet where a reduction was planned.

CONCLUSIONS

Less than half of the planned overjet reduction and less than a third of the planned AP FPM correction were achieved with the MAA. Almost 20% of patients completed the MAA phase of treatment with an increased overjet despite a reduction being planned.