Clear Aligner Therapy Concerns: Addressing Discrepancies Between Digitally Anticipated Outcomes and Clinical Ground Realities.

Expeditious strides in the fields of biomaterials, computer-aided design, and manufacturing have catapulted clear aligner therapy (CAT) to become a comprehensive orthodontic treatment modality. The efficiency of achieving planned tooth movement with clear aligners is a significant consideration while setting up the final treatment goals, as well as calculating treatment times and costs based on the available evidence. Contemporary research outcomes confirm that one of the most commonly reported clinical concerns with CAT is the discrepancy between the prescribed outcome in the digital treatment plan and the clinically achieved outcome from a given series of aligners. Inaccurate prediction of tooth movements may not only lead to a prolonged duration of aligner treatment with an additional need for refinement strategies; but it may also cause other concerns, such as patient burnout and increased potential for relapse. The authors of this paper have elucidated some of the critical elements that may help address this discrepancy between digitally prescribed and clinical outcomes based on an evidence-based approach with regard to the predictability and accuracy of CAT. A strong diagnostic acumen, judicious case selection, solid biomechanical understanding of various types of orthodontic tooth movements, a research framework that keeps pace with technological and material developments and provides evidence-based knowledge of the limitations of CAT; and above all, the ability of the clinician to continually innovate as per different clinical scenarios, all contribute to attaining treatment predictability, efficacy, and efficiency with CAT.

Clear aligner therapy practices among orthodontists practicing in Canada.

BACKGROUND: The acceptability and preference for clear aligner therapy (CAT) has been increasing among orthodontists, but there is still a lack of consensus regarding CAT best practices. Consequently, this study aimed to investigate CAT practices among orthodontists practicing in Canada. METHODS: The survey was conducted among orthodontists practicing in Canada using a modified previously published survey. Sixty orthodontists participated (6.1% response rate). It consisted of 11 sections with open and closed questions related to demographic information and particularities about using or not using CAT. The survey responses were exported from REDCap to a Microsoft Excel (Microsoft, Redmond, Wash) spreadsheet, then statistically analyzed using SPSS software (SPSS for Windows, version 21.0; IBM Inc., Armonk, NY, USA). The comments were categorized under themes and subthemes. Data were organized in descriptive statistics, expressing frequencies and percentages. RESULTS: Almost 30% of the orthodontist's annual caseload was treated with CAT, most frequently prescribed to adult patients. Case complexity and patient cooperation were the factors that most influenced the decision to prescribe CAT. Almost half of orthodontists reported sometimes combining CAT with adjunctive fixed appliances. CONCLUSIONS: Most orthodontists prescribe CAT, and its use is based on the malocclusion's complexity. Orthodontists who do not prescribe CAT believe that fixed appliance therapy has superior treatment outcomes.

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.

Comparison of digital study model superimposition methods using implant-supported crowns and best-fit algorithms.

INTRODUCTION: Research regarding orthodontic changes using the superimposition of digital study models (DSMs) is commonplace. Information regarding the accuracy of data processing by superimposition software is limited. The study aimed to compare different methods of superimposing DSMs using implant-supported crowns (ISC) as a stable reference structure. METHODS: DSMs containing ISCs were sourced from a database of patients treated with clear aligner therapy. The DSM representing the planned treatment outcome was superimposed on the pretreatment DSM. Three tooth points were selected for comparison on the contralateral side of each ISC. Differences in Cartesian coordinates for each tooth point for each arch superimposition method, used by the Geomagic Control X (3D systems, Rock Hill, NC) software system, were recorded. Paired t tests for the reference standard superimposition method best-fit high-resolution using the entire dental arch compared with initial, best-fit low-resolution, and best-fit high-resolution using the ISC only were calculated. RESULTS: The DSMs of 54 dental arches containing ISCs were evaluated. All mean differences for displacements of selected points on the contralateral side to the ISC in the 3 Cartesian planes were <0.05 mm (P <0.05) and below the threshold of clinical significance. In addition, the standard superimposition techniques (initial, best-fit low-resolution, and best-fit high-resolution) resulted in nonstatistically significant and nonclinically significant differences in the position of the ISC. CONCLUSIONS: Researchers can be confident that the described superimposition methodologies, with and without ISCs as a stable reference structure, are a valid method for accurately assessing most intraarch dental changes.

Efficacy of planned moderate to severe torque changes in maxillary central incisors with the Invisalign appliance: A retrospective investigation.

INTRODUCTION: This study aimed to investigate whether there was a difference between the planned and achieved lingual root torque of the maxillary central incisors in patients treated with an initial series of Invisalign (Align Technology, Santa Clara, Calif) aligners in which >10° change in the inclination of these teeth was prescribed via the ClinCheck facility. METHODS: The pretreatment, planned, and the digital models after wear of the initial series of aligners regarding adult patients who satisfied selection criteria and were treated using the Invisalign appliance were measured using the Geomagic Control X software (version 2017.0.3; 3D systems, Rock Hill, SC). RESULTS: A sample of 63 patients with 126 maxillary central incisors satisfied the inclusion criteria. The mean accuracy of the planned torque change of the maxillary central incisors that was achieved was 41.9%. A clinically significant shortfall (≥5°) was detected in 78.6% of the incisors, with the majority showing an underexpression between 10°-15°. Linear regression analyses indicated that weekly or biweekly wear protocols or the presence or absence of power ridges did not influence the accuracy of planned torque expression (P >0.05). CONCLUSIONS: The changes in torque expression with an initial series of Invisalign aligners were less than half of what was planned in patients in which at least a 10° change in lingual root torque of these teeth was prescribed. The presence of power ridges and the aligner change protocol did not appear to significantly affect the accuracy of maxillary central incisor torque expression.

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.

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.

Clinical expression of programmed maxillary buccal expansion and buccolingual crown inclination with Invisalign EX30 and SmartTrack aligners and the effect of 1-week vs. 2-week aligner change regimes: A retrospective cohort study.

Objective: : This retrospective cohort study aimed to assess and compare the accuracy of 3 different Invisalign® treatment regimens in terms of variations of aligner change frequency and type of aligner material in achieving maxillary dental buccal expansion. Methods: : Altogether, 120 adult patients whose treatment involved maxillary dental expansion with Invisalign® were included. The patients were divided into 3 groups, with each group comprising 40 patients as follows: SmartTrack® 1-week changes (ST1), SmartTrack® 2-week changes (ST2), and EX30® 2-week changes (EX2). The groups were assessed by comparing actual changes achieved with those prescribed by ClinCheck®. The rates of clinically significant inaccuracies (CSI) observed for buccal expansion (≥ 0.5 mm) and buccolingual inclination (≥ 2°) during expansion were then determined. Results: : In terms of expansion, the ST1 group demonstrated the highest CSI rate at all tooth levels, whereas the ST2 group had the lowest rate of CSI and the lowest mean inaccuracy for each tooth level. In terms of buccolingual inclination, the ST1 group had the highest CSI rate across all tooth levels, whereas the EX2 group had the lowest CSI rate at all tooth levels except for the canine level where the ST2 group had the lowest CSI rate. A tendency toward overexpression of buccal crown inclination, and underexpression of buccal expansion was observed at all tooth levels. Conclusions: : Two-week aligner change regimens offer improved accuracy compared with 1-week aligner changes. SmartTrack® 2-week changes were the most accurate for buccal expansion, whereas EX30® 2-week changes were the most accurate for buccolingual inclination.

Invisalign Lite: a cross-sectional investigation of orthodontist treatment-planning practices.

OBJECTIVES: To survey treatment-planning practices of orthodontists related to the Invisalign Lite clear aligner appliance (Align Technology, San Jose, Calif). MATERIALS AND METHODS: Patients satisfying inclusion and exclusion criteria and treated with Invisalign Lite were selected from a database containing more than 17,000 patients. Relevant data regarding treatment-planning practices were obtained from Align Technology's treatment-planning facility, ClinCheck, and evaluated. RESULTS: Most (n = 135; 79.9%) patients were female and had a median (interquartile range [IQR]) age of 30.5 (23.8, 43.1) years. The median (IQR) number of aligners for the sample was 23.0 (14, 28) for the maxilla and 24 (14, 28) for the mandible. Most (n = 122; 72.2%) patients required at least one additional series of aligners. More locations for interproximal reduction (IPR) were prescribed in the mandible (mean 1.91 [1.78]) than in the maxilla (1.03 [1.78]; P < .024) in the initial accepted plan of all patients. More teeth were prescribed composite resin (CR) attachments in the maxilla (P < .0001) in the initial accepted plan of all patients. Issues regarding tooth position protocols (n = 50; 53.3%) and requirement for additional IPR (n = 68; 45.3%) were reasons for treatment plan changes before acceptance of the initial treatment plan by orthodontists. CONCLUSIONS: More than 7 of 10 patients required at least one additional series of aligners after the initial series of Invisalign Lite aligners was completed. Prescription of IPR was more common in the mandible, and prescription of CR attachments was more common in the maxilla.

Interproximal reduction in the refinement phase of Invisalign treatment: A quantitative analysis.

INTRODUCTION: Interproximal reduction (IPR) is a common adjunct to contemporary orthodontic treatment. This study aimed to carry out a quantitative analysis of IPR prescribed in the refinement phases of clear aligner therapy with the Invisalign appliance (Align Technology, San Jose, Calif). METHODS: The digital treatment plans (DTPs) of a total of 330 patients treated by 11 orthodontists were evaluated. Relevant data regarding patient age, gender, and prescription of IPR in the initial and refined DTPs were obtained from Align Technology's digital interface, ClinCheck. Computational analyses included descriptive statistics, Mann-Whitney U, and Kruskal-Wallis tests. RESULTS: Most (n = 182; 75.2%) of the 242 patients who satisfied inclusion criteria were females. The median (interquartile range [IQR]) age was 29.2 (22.1-40.2) years. More than 60% of the contact sites prescribed IPR related to the initial DTP (n = 1312; 60.4%), with 39.6% (n = 859) recorded in the refinement DTPs. A median (IQR) of 1.1 (0.6-2.1) mm of IPR was prescribed per patient in the initial DTP compared with a median (IQR) of 0.6 (0.3-1.3) mm in the refinement DTPs. The most common site for prescribed IPR in all DTPs was the mandibular anterior region. Almost half (n = 108; 44.6%) of the patients were prescribed IPR at the same contact point site more than once during treatment. CONCLUSIONS: Almost 40% of the contact points that were prescribed IPR were in the patients' refinement DTPs. Most IPR was prescribed for the anterior region of the mandible. Almost half of the patients had IPR repeatedly prescribed at the same sites during treatment.

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.

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

OBJECTIVES: To investigate whether the predicted changes in overbite (OB) and overjet (OJ) in Align Technology's (Santa Jose, Calif) digital treatment plan for the prescribed course of treatment with the Invisalign appliance were consistent with those same changes in OB and OJ measured with the Geomagic Control X (Geomagic US, Research, Triangle Park, NC) metrology software system. MATERIALS AND METHODS: Geomagic Control X software was used to determine OB and OJ differences between the pretreatment and predicted outcome. STL files for patients satisfying inclusion criteria and undergoing nonextraction orthodontic treatment with the Invisalign appliance. The differences were compared, using the Bland-Altman analysis, to the corresponding data provided by Align Technology's digital treatment-planning interface, ClinCheck. RESULTS: Data regarding 76 adult patients who satisfied strict inclusion criteria were assessed. The Shapiro-Wilks test indicated normality (P > .05). The Bland-Altman analysis showed high levels of agreement between the two measurements, with a bias range of -0.131 to 0.111 for OB and -0.393 to 0.03 for OJ recorded. CONCLUSIONS: Clinicians and researchers can be confident that measurement data provided by Invisalign's ClinCheck digital treatment-planning facility concerning OB and OJ changes from the initial to the predicted treatment outcome are valid.

Comparison of labio-palatal incisor movement between two wear protocols: a retrospective cohort study.

OBJECTIVES: To investigate the accuracy of the Invisalign appliance in achieving predicted angular tooth movement of the maxillary central incisors, to locate the center of rotation in a labio-palatal direction, and to investigate any difference between 1-weekly and 2-weekly wear protocols. MATERIALS AND METHODS: This study involved a retrospective sample of two groups of 46 Class I adult subjects treated non-extraction with different protocols of 1-weekly and 2-weekly wear. The pretreatment, predicted outcome and achieved outcome digital models were superimposed and measured using metrology software. Angular and center-of-rotation measurements in the sagittal plane for the maxillary right central incisor were analyzed. RESULTS: There was a statistically significant difference between predicted and achieved angular measurements (P < .005) for labial tooth movements regardless of wear protocol. For palatal movements, no statistically significant difference was observed (P > .05). A small amount of overexpression was observed in some cases. Regarding crown and root control, uncontrolled tipping was the most predictable. No statistically significant difference was found between predicted and achieved center of rotation, but the confidence interval was wide. No statistically significant difference (P > .05) was found between the two wear protocols for the parameters measured. CONCLUSIONS: For maxillary central incisors, labial angular movements were not as accurate as palatal movements. Overcorrection could be recommended with careful clinical monitoring due to the possibility of overexpression. Control of root movements may be unpredictable, and further research is required to draw stronger conclusions. For the parameters measured in this clinical sample, there was no difference between the two wear protocols.

Predicted and achieved overjet and overbite measurements with the Invisalign appliance: a retrospective study.

OBJECTIVES: To determine whether achieved outcome regarding overjet and overbite matched the predicted outcome following treatment with Invisalign (Align Technology, San Jose, Calif) aligner appliances. MATERIALS AND METHODS: Data including pretreatment, predicted and achieved overjet, and overbite measurements provided by Align's digital treatment facility, ClinCheck Pro, were evaluated. Descriptive statistics, Mann-Whitney U-test, and Wilcoxon rank-sum intraclass correlation (ICC) test results were calculated. RESULTS: From an initial sample of 600, 355 adult patients satisfied the inclusion and exclusion criteria. ICC scores for data input were excellent. Median (interquartile range [IQR]) age was 30.14 (23.33, 39.92) years and most (n = 259; 72.95%) were women. Almost one-third (n = 101; 28.45%) had undergone extraction as part of their treatment. More aligners were prescribed in the initial digital treatment plan for patients (median, 44; IQR: 35, 51.5; minimum, 17; maximum, 92) undergoing extractions as part of their orthodontic treatment than those who were not (median, 24; IQR: 18.25, 32; minimum, 13; maximum, 85) (P < .0001). Planned changes in overjet differed significantly from achieved outcomes (P < .001). Planned increases in overbite resulted in up to more than twice (222.72%) as much increase than predicted. Planned reduction of overbite achieved 8.69% of its predicted reduction in extraction cases. CONCLUSIONS: Achieved overjet and overbite measurements differed significantly from the predicted outcomes at the end of an initial sequence of aligners. Planned increases in overbite resulted in greater overbite correction than predicted, particularly in extraction cases. Planned overbite reduction was challenging, especially in patients with extractions.

Clear aligner therapy practice among orthodontists in the United Kingdom and the Republic of Ireland: A cross-sectional survey of the British Orthodontic Society membership.

OBJECTIVE: To investigate clear aligner therapy (CAT) practice among orthodontists in the British Orthodontic Society (BOS). DESIGN: A cross-sectional online survey. METHODS: An electronic survey was distributed to members of the BOS in 2022. The survey comprised questions regarding respondent demographics, general use of CAT, the choice of proprietary CAT appliances, CAT planning, case selection, treatment protocols and orthodontist-reported CAT problems. RESULTS: Overall, 233 (19.5%) responses were received with the majority (n = 121, 53.1%) being female. Most respondents reported practising in England (n = 171, 74.7%). The majority (n = 177, 77.3%) indicated that they used CAT in their practice, with 48.1% (n = 81) treating 1-20 patients with CAT annually. The most frequently prescribed CAT system was Invisalign (n = 138, 81.2%). One to three changes to the initial digital treatment plan were made by 72.9% (n = 121) with final tooth positions being the most common reason for adjustment (64.4%). Most (n = 97, 60.3%) rarely or never performed premolar extractions with CAT. Of the respondents, 23 12.7%) reported that they always or mostly used a remote monitoring system in conjunction with CAT, with a wide range of aligner change protocols reported. The median number of months required to complete non-extraction CAT reported by the respondents was 12. Most respondents (n = 77, 51.7%) did not feel that CAT provides superior outcomes compared with fixed appliance therapy. CONCLUSION: CAT practice varied widely among the surveyed orthodontists. A predilection for the use of Invisalign and utility in less severe cases was noted.

Predictability of anterior open bite treatment with Invisalign.

INTRODUCTION: Anterior open bite correction with Invisalign has been claimed to have relatively good predictability because of the proposed function of clear aligners to function as occlusal bite-blocks, limiting extrusion of the posterior teeth or possibly even intruding posterior teeth. This proposal, however, remains relatively unsubstantiated. The objective of this study was to investigate and determine the accuracy of Invisalign treatment in correcting anterior open bite by comparing the predicted outcome from ClinCheck to the achieved outcome for the initial aligner sequence. METHODS: A retrospective study used pretreatment and posttreatment intraoral scans and predicted outcomes (ClinCheck) stereolithography files of 76 adult patients from private specialist orthodontic practices. Inclusion criteria comprised nonextraction treatment, with a minimum of 14 dual arch Invisalign aligners. Geomagic Control X software was used to measure overbite and overjet in the pretreatment, posttreatment, and predicted outcomes stereolithography files for each patient. RESULTS: Approximately 66.2% of the programmed open bite closure was expressed compared with the prescribed ClinCheck outcome. The use of posterior occlusal bite-blocks and prescribed movement of teeth via anterior extrusion, posterior intrusion, or a combination of the 2 made no difference to the efficacy of open bite closure. Two-week aligner changes resulted in 0.49 mm more bite closure on average. CONCLUSIONS: The prescribed bite closure in ClinCheck software overestimates the bite closure that is clinically achieved.

The predictability of maxillary curve of Spee leveling with the Invisalign appliance.

OBJECTIVES: To evaluate the predictability of the Invisalign appliance (Align Technology, Santa Clara, Calif) in leveling the maxillary curve of Spee (COS). MATERIALS AND METHODS: A retrospective sample of adult subjects treated with the Invisalign appliance between 2013 and 2019 were selected. Patients were treated nonextraction in the maxillary arch and had either Angle Class I or II malocclusions with a minimum of 14 aligners with no bite ramps. Initial, predicted, and actual outcomes were analyzed with Geomagic Control X software (version 2017.0.3; 3D Systems, Cary, NC). RESULTS: A sample of 53 cases satisfied inclusion/exclusion criteria. Paired t-tests demonstrated a significant difference between mean predicted and actual maxillary COS leveling with a shortfall of 0.11 mm (SD = 0.37; P = .033). Planned intrusion tended to be more accurate posteriorly with an overexpression of 117% for the first molars. Planned extrusion was the least accurate, with the mid-arch demonstrating expressions of -14% to -48%. These teeth intruded despite a prescribed extrusive movement. CONCLUSIONS: The Invisalign appliance did not accurately predict maxillary COS leveling. Planned intrusive movements were overcorrected, and planned extrusive movements were either undercorrected or resulted in intrusion. This effect was most apparent for the upper first molar, which expressed 117% and -48% of planned intrusion and extrusion, respectively.

The predictability of maxillary curve of Wilson leveling with the Invisalign appliance.

BACKGROUND: This retrospective study aims to evaluate the predictability of the Invisalign appliance (Align Technology, Santa Clara, CA) in leveling the maxillary curve of Wilson (COW). METHODS: 53 adult subjects treated by orthodontists who are experienced Invisalign providers, between 2013 and 2019 were selected. All patients had either Angle Class I or II malocclusions and were treated by non-extraction in the maxillary arch with a minimum of 14 Invisalign aligners with no bite ramps or auxiliaries. Initial, predicted, and actual outcomes were analyzed with Geomagic Control X software (3D systems, Rock Hill, SC; Version 2017.0.3). RESULTS: Despite planning mean (SD) COW leveling of 0.25 mm (1.91), the curve became significantly more pronounced by 1.15 mm (0.85) (P < .001). There was a significant overexpression of buccal inclinations between mean prescribed versus actual values from 0.10 mm (0.39) (P = .007) to 0.29 mm (0.47) (P < .001) from the first premolars to the second molars, respectively. These differences were more pronounced posteriorly. The differences between the predicted and actual arch width values were underexpressed for all teeth except the second molars; a mean underexpression between 0.28 mm (0.92) and 0.60 mm (1.14). The second molars were the only teeth to overexpress with a mean of 0.42 mm (1.02). CONCLUSIONS: Overall mean maxillary COW was not predictably controlled with Invisalign. The appliance tends to overexpress the buccal crown tip regardless of prescribed direction, especially posteriorly. Arch expansion was underexpressed at all levels of the arch except for second molars which overexpressed by almost four times.

Treatment planning protocols with the Invisalign appliance: an exploratory survey.

OBJECTIVES: To investigate the changes made by orthodontists to the initial digital treatment plan (DTP) regarding the Invisalign appliance provided by Align Technology until acceptance of the plan by the orthodontist. MATERIALS AND METHODS: The DTPs of subjects who underwent treatment with the Invisalign appliance and satisfied inclusion criteria were assessed to determine the number of DTPs and changes regarding prescription of aligners, composite resin (CR) attachments, and interproximal reduction (IPR) between the initial DTP and the accepted plan. Statistical analyses were calculated via GraphPad Prism 9.0 (GraphPad Software Inc., La Jolla, Calif). RESULTS: Most of the 431 subjects who satisfied inclusion/exclusion criteria were female (72.85%). More DTPs were required for subjects who had orthodontic extractions (median [interquartile range; IQR]: 4 [3, 5]) compared with those who did not (median [IQR]: 3 [2, 4], P < .0001). The median (IQR) overall number of aligners prescribed in the accepted DTP (30 [20, 39]) was greater than the initial DTP (30 [22,41], P < .001). The number of teeth used for CR attachments increased from the initial to the accepted DTP (P < .001). More CR attachments were observed in extraction treatment DTPs with a prescribed 2-week aligner change protocol compared with nonextraction treatment (P < .0001). The number of contact points with prescribed IPR increased between initial and accepted DTPs (P < .0001). CONCLUSIONS: Significant changes regarding DTP protocols were observed between the initial and accepted DTPs and between nonextraction and extraction-based CAT.

Digital treatment planning and clear aligner therapy: A retrospective cohort study.

OBJECTIVE: To investigate the total number of digital treatment plan (DTPs) and aligners manufactured for clear aligner therapy (CAT) by Invisalign® from initial treatment planning to the completion of CAT. DESIGN: A retrospective cohort study. MATERIAL AND METHODS: A total of 30 patients, from each of 11 experienced orthodontists, who commenced treatment over a 12-month period, were assessed regarding the number of DTPs and aligners prescribed from initial planning to completion of CAT. Patients were categorised according to the number of aligners prescribed by the initial DTP into mild (<15), moderate (15-29) or severe (>29). RESULTS: After the application of inclusion/exclusion criteria, 324 patients (71.9% women; median age = 28.5 years) undergoing non-extraction treatment with the Invisalign® appliance were assessed. The median number of initial DTPs was 3 (interquartile range [IQR] = 2, 1-9) per patient before acceptance by the orthodontist. Most (99.4%) patients required a refinement phase with a median of 2 (IQR = 2, 2-7) refinement plans recorded. A total of 9135 aligners per dental arch, was prescribed in the initial DTP of the 324 patients assessed and 8452 in the refinement phase. The median number of aligners per dental arch prescribed from the initial DTP was 26 (IQR = 12, 6-78) and from the refinement plans was 20.5 (IQR = 17, 0-132). CONCLUSION: A median of three initial DTPs and two refinement plans were required for patients undergoing non-extraction treatment with the Invisalign® appliance. Patients were prescribed almost double the number of aligners initially predicted to manage their malocclusion.