Assessment of the Efficacy of the Aerodentis System: Complete Statistical Analysis

1. Trial at a Glance

This page covers the registry results for Assessment of the Efficacy of the Aerodentis System (NCT03421886), a randomized na study. The primary outcome is Litter's Index (Change in Little's Index Mean Total Score From Baseline).

2. Clinical Question

3. Trial Design

The registry describes a two-arm, parallel-group study of the Aerodentis System and Invisalign clear aligners. Its design fields list randomized allocation and single masking, while the brief summary calls the study open-label. The arm descriptions say participants would be “systematically assigned.” These descriptions do not fully agree, and the registry record does not clarify the allocation or masking procedures. The record also describes the study as a non-inferiority clinical study, but does not report a non-inferiority margin or a statistical analysis demonstrating non-inferiority.

The planned enrollment was 45. The summary describes 30 participants wearing Aerodentis and 15 wearing Invisalign, with treatment and follow-up for up to fifteen months. The record says assessments were planned every 4 weeks and would include tooth movement and quality-of-life assessments. It describes an average treatment duration of 10 months for the primary endpoint timeframe. Actual treatment durations, follow-up completion, and the number of participants included in the outcome analysis are not reported in the registry record.

The record lists the study as completed, with a start date of 2016-07-21 and primary completion date of 2019-07-21. It lists the University of Alabama at Birmingham as sponsor. Although the record identifies one primary outcome measure, its reporting structure indicates several categories or time points and does not reduce them to one comparison. No analysis records are listed, and the primary outcome results are not reported in the registry record.

4. Participant Flow and Accounting

The registry reports how participants moved through each stage of the study. All counts below are exactly as posted; missing counts are not inferred from other stages.

Overall Study

5. Baseline Characteristics

The table reproduces the baseline characteristics posted in the registry, which describe the participants analysed at baseline and help show whether the randomized groups were comparable.

6. Primary Endpoint

The registry lists the primary outcome as Litter's Index (Change in Little's Index Mean Total Score From Baseline), measured over Movement was recorded by capturing the start and end point of the 6 anterior teeth before and at the completion of the treatment respectively. Changes was compared and assessed. The duration of the treatment was an average of 10 months..

The primary outcome is the change in the mean total Little's Index score from baseline. The index assesses displacement at five contact points among the lower anterior teeth, described in the outcome definition as lower 1's through 3's. The distances at those points, recorded in millimeters, are summed to represent anterior irregularity. The record's outcome title spells the name as “Litter's Index,” while its description uses “Little's Index.”

For this endpoint, the record says the start and end positions of the six anterior teeth were captured before treatment and at completion. The index was measured at baseline and endpoint, and the change from baseline was compared between the investigational and control groups. A negative change represents a decrease in anterior irregularity. This direction is useful for interpreting the scale, but it does not establish the magnitude or precision of any group difference.

As a general statistical point, a continuous endpoint such as a millimeter score can be summarized by a group mean and standard deviation. The mean describes the average observed score or change, while the standard deviation describes how spread out individual measurements are around that mean. The registry record does not report the group means, standard deviations, or a between-group estimate for this endpoint.

7. Why No Re-analysis Is Shown

8. Statistical Interpretation

9. Statistical Methods Explained

What does the endpoint summary represent?

The primary measure is continuous: a millimeter score derived from the summed displacement at five contact points. The registry identifies the summary measure as a mean and the dispersion measure as a standard deviation. In general, a mean gives the average score in a group, while a standard deviation conveys how much individual observations vary around that average. Neither statistic alone describes the difference between treatment groups, and neither is reported numerically for this outcome in the registry record.

The described comparison concerns change from baseline to endpoint. A change score uses each participant's endpoint measurement relative to that participant's baseline measurement. The registry says a negative change indicates reduced anterior irregularity. To compare groups, an analysis would generally need to report the average change in each group and a between-group estimate, together with uncertainty. The registry record does not report those results or state which statistical test or model was used.

How should uncertainty be understood?

As a general explanation, a confidence interval communicates the statistical uncertainty around an estimate. A narrower interval indicates greater precision under the assumptions of the analysis; a wider interval indicates less precision. In a comparison of mean changes, the interval would help readers assess which differences remain compatible with the observed data. No interval or estimate is reported for the primary outcome in this record, so its precision cannot be evaluated.

A hypothesis test addresses compatibility between the data and a specified null hypothesis under a statistical model. Its p-value does not show the probability that a treatment is effective, nor does it measure clinical importance. For a non-inferiority question, interpretation also requires the non-inferiority margin and a suitable analysis of the treatment contrast. The record does not report the margin, p-value, or analysis used, so no test-based interpretation is available.

What does the non-inferiority description require?

In general, a non-inferiority design asks whether the uncertainty around a treatment comparison excludes differences beyond an agreed margin in the unfavorable direction. The margin needs to be specified before interpreting results, and the estimate must be reported on a scale with a clear direction. The registry describes this study as non-inferiority but does not report the margin or results. Its design label cannot, by itself, support a claim that one treatment was non-inferior to the other.

The record's allocation descriptions also merit care. One field identifies randomized allocation, while the arm descriptions say participants would be systematically assigned. The summary calls the study open-label, whereas another design field lists single masking. These statements are inconsistent or insufficiently detailed to establish the exact allocation and masking procedures. The registry record does not resolve the discrepancy.

What can be inferred from the listed planning approach?

The record describes a planning illustration based on the observed effect, with a two-sided significance level of 0.05, equal allocation between groups, and a normal approximation. It says the effect to detect is a stated fraction of the observed effect. This is a planning framework, not an account of the trial's original sample-size justification. The numerical planning outputs are not reported in the registry record, and no sample-size conclusion can be drawn from the assumptions alone.

As a general point, planning calculations depend on the effect size, outcome variability, significance level, desired power, allocation, and analysis assumptions. Changing the effect targeted changes the resulting planning requirement. Any sample-size figure generated from an observed effect is an illustration for planning, not observed power and not proof that the completed study was adequately sized. The registry record does not report the trial's own sample-size justification or a statistical analysis plan.

How could repeated assessments affect analysis?

The summary says outcome assessments were planned every 4 weeks, while the primary endpoint description refers to baseline and endpoint measurements. Repeated measurements can be informative about the course of change, but they also create choices about which time point or summary should answer the primary question. General approaches may compare a prespecified endpoint, model repeated measurements, or analyze change over a specified period. These approaches answer different questions and rely on different assumptions. The registry record does not say which method was used or how the reported categories and time points were selected.

When individuals have different follow-up durations, the endpoint may occur at different times. The record describes follow-up until an index threshold of <1.5 or up to 15 months, whichever came first, and states that treatment duration averaged 10 months. As a general matter, analyses should make clear how varying endpoint times and participants who stop early are handled. That method is not reported in the registry record.

10. Multiplicity, Missing Data and Analysis Populations

The record lists one outcome measure, but its reporting note says the primary outcome has several categories or time points and is not reduced to one comparison. This makes it difficult to identify a single reported primary contrast. If multiple outcomes, time points, or analyses are considered, the choice of which results to emphasize can affect interpretation. As a general statistical matter, multiplicity procedures or a prespecified hierarchy can help control the risk of misleading conclusions from selecting among many comparisons. The registry record does not report a multiplicity plan.

The statistical analysis plan, analysis population, and handling of missing outcome data are not reported in the registry record. It is also not reported how many participants completed treatment or contributed endpoint measurements, whether analyses followed assigned groups, or how participants who discontinued were handled. These details matter because excluding participants or imputing unobserved measurements can affect the estimated comparison, particularly when missingness relates to outcomes or treatment experience.

The record does not describe interim analyses, stopping rules, or adjustments for interim looks; these are not reported in the registry record. No analysis records are listed. In the absence of those details and the primary outcome results, readers cannot assess the analysis population, the extent of missing data, or whether the reported analysis corresponds to a prespecified plan.

11. Safety Results

The registry reports serious adverse events as affected participants divided by participants at risk.

Deaths

Other (non-serious) adverse events

Participants with at least one non-serious event at or above the registry's 0% reporting threshold.

The registry lists safety counts separately for the Aerodentis System and Invisalign Clear Aligner System groups. For Aerodentis, 30 participants are listed as at risk for serious adverse events and 0 as affected; 30 are listed as at risk for other adverse events and 0 as affected; deaths are listed as 0. For Invisalign, the corresponding figures are 15 at risk for serious adverse events and 0 affected, 15 at risk for other adverse events and 0 affected, and 0 deaths. No serious adverse event terms are listed.

These figures describe what the registry reports; they should not be read as proof that no adverse events occurred outside the registry's reporting or observation process. The record does not describe event ascertainment, follow-up completeness, severity grading beyond the serious/other categories, or the relationship of events to treatment. It also does not provide event narratives or other safety analyses.

As a general statistical point, a zero count in a group does not establish that the underlying risk is zero. Safety estimates can remain uncertain when event counts are low, and interpretation depends on the duration and completeness of follow-up and the way events were collected. Those details are not reported in the registry record.

12. What the Result Does, and Does Not, Mean

The record describes a trial intended to compare the Aerodentis System with Invisalign using change in Little's Index of Displacement as its primary clinical endpoint. It explains how the index represents anterior irregularity and states that a negative change reflects a decrease in irregularity. The record also lists safety counts with zero affected participants and zero deaths in both groups.

What the record does not establish is the size or precision of any treatment difference. It provides no group outcome values, comparative estimate, confidence interval, or p-value for the primary endpoint. It therefore cannot show whether changes differed between groups, how large a difference may have been, or how much uncertainty surrounds a comparison. Nor does the non-inferiority description establish that non-inferiority was demonstrated: the margin and statistical analysis are not reported.

As a general principle, a study's design label and stated objective are not substitutes for its results. Interpretation requires the observed outcomes, the analysis method, and adequate information about the participants included and their follow-up. The registry record does not report those details for the primary outcome. In addition, inconsistencies in descriptions of allocation and masking leave the conduct of the design unclear.

The safety counts should likewise be understood as registry entries rather than a guarantee of absence of risk. The record does not give enough information about how events were collected or how complete follow-up was to assess the scope of safety surveillance. Overall, the registry record documents the intended comparison, endpoint definition, and listed safety counts, but it does not provide sufficient results to draw a comparative efficacy conclusion or a comprehensive safety interpretation.

13. Why This Trial Matters Statistically

This study raises several statistical issues that are central to interpreting comparative orthodontic research. Its endpoint is a continuous measurement of tooth displacement, with repeated observations described during treatment and a baseline-to-endpoint comparison identified as primary. Clear reporting of the endpoint time, group summaries, treatment contrast, and uncertainty would allow readers to understand both the direction and precision of the result.

The non-inferiority objective makes the prespecified margin especially important. Without that margin and a confidence interval for the treatment contrast, it is not possible to determine whether the data rule out differences considered unacceptable under the study's criterion. A study can be described as non-inferiority without the registry record containing enough information to evaluate that claim.

The record also illustrates why design details need to be coherent. Randomized allocation is listed, but “systematically assigned” appears in the arm descriptions; open-label appears in the summary, while single masking appears in a design field. Resolving these descriptions would help readers assess the planned comparison and potential sources of bias. Reporting the analysis population, missing-data approach, and handling of multiple time points would further clarify the evidential basis for any estimate.

Because the registry record contains no primary outcome results or analysis records, these issues remain unresolved for this study. The available description can define the statistical questions readers would need answered, but it cannot establish the comparative outcome.

14. Limitations

• The posted summary statistics are the only data these results rest on; patient-level data, full protocols and statistical analysis plans are not available.
• Recalculated results are simple, unadjusted calculations from posted summaries. They do not replace the sponsor's prespecified analysis.

Important details specific to this trial are absent or inconsistent in the registry record. Although randomized allocation is listed, the arm descriptions state that participants would be “systematically assigned.” The summary calls the study open-label, but a design field lists single masking. The record does not explain these differences, so the actual allocation and masking procedures cannot be determined from the registry description.

The record does not report the primary outcome values, the between-group comparison, its uncertainty, or an analysis method. Although the study is described as non-inferiority, the margin and statistical plan are not reported in the registry record. The reporting note also indicates multiple categories or time points without a single reduced comparison. The approach to multiplicity is not reported.

Follow-up was described as continuing until an index value of <1.5 or up to 15 months, whichever came first, and the average treatment duration was described as 10 months. The record does not report actual follow-up by group, how endpoint timing varied, or how participants who stopped early were handled. Eligibility criteria, baseline group characteristics, adherence, analysis populations, and missing-data methods are also not reported in the registry record.

The listed safety counts lack detail about event collection and follow-up completeness. The record does not report the trial's sample-size justification or analysis records. These gaps prevent a full appraisal of the intended and conducted analyses, as well as the precision and robustness of any treatment comparison.

15. Related Tutorials

16. Related Statistical Calculators

17. Sources

• ClinicalTrials.gov: Assessment of the Efficacy of the Aerodentis System — NCT03421886.
• Registry record last updated 2020-11-04; status last verified 2020-10.
• Results first posted 2020-11-04.
• Data retrieved from ClinicalTrials.gov on 2026-11-09.
• Group sizes, means, event counts and sponsor-reported p-values are reproduced as posted. Effect estimates, confidence intervals and p-values not attributed to the sponsor are independently calculated from the posted summary statistics.

18. Record Summary

The registry record describes a completed, two-arm, parallel-group study sponsored by the University of Alabama at Birmingham, comparing the Aerodentis System with Invisalign clear aligners for orthodontic tooth movement. It lists planned enrollment of 45 and identifies change in mean Little's Index of Displacement from baseline as the primary outcome. The study is described as non-inferiority, with follow-up for up to 15 months and assessments planned every 4 weeks.

The endpoint definition states that negative change represents decreased anterior irregularity. The registry record does not report primary outcome values, a comparative estimate, confidence intervals, or analysis records. It also does not report the non-inferiority margin, analysis plan, missing-data handling, or analysis population. Allocation and masking descriptions are not fully consistent. Safety listings show zero affected participants and zero deaths in each group, with no serious adverse event terms listed. The record supports a description of the study question and endpoint, but does not support a comparative outcome conclusion.