Accelerated Tooth Movement With AcceleDent® and Aligners - a Pilot Project: Complete Statistical Analysis

1. Trial at a Glance

This page covers the registry results for Accelerated Tooth Movement With AcceleDent® and Aligners - a Pilot Project (NCT02438280), a randomized na study. The primary outcome is Ability to Complete Treatment Aligners in Conjunction With an Active and Placebo Vibration Device (AcceleDent® Aura).

2. Clinical Question

3. Trial Design

NCT02438280 is listed as a completed, randomized, parallel-group trial sponsored by the University of Washington. The registry lists the phase as not applicable. Enrollment is 27. The two posted arms are A (Active Device) and B (Control Device), with 13 participants recorded in each arm for the primary outcome. The brief description says the study would have 12 participants in each group, so the planned group counts and the posted outcome counts differ; the reason is not reported in the registry record.

The active arm used an AcceleDent device and the control arm used a sham AcceleDent device. Both arm descriptions specify use for 20 minutes each day during aligner treatment. Participants in both groups were asked to change aligners every week. The brief description characterizes the study as triple-blind, while the registry design information lists quadruple masking. The exact roles masked and how masking was maintained are not reported in the registry record.

The primary outcome was assessed at 6 months and concerned completion of the initial set of aligners. A secondary outcome assessed final alignment scores of the upper and lower incisors at 6 months, using Little's irregularity index in millimeters. The registry lists two outcome measures overall and one posted secondary endpoint. It does not give a detailed account of recruitment, allocation concealment, the statistical analysis plan, or the handling of participants who did not complete follow-up. Those details are not reported in the registry record.

The background description says the device's theory was that high-frequency vibration could stimulate bone remodeling and that the product was also claimed to reduce pain and discomfort. The posted primary outcome concerns aligner completion, not pain or treatment duration as a separate endpoint. The trial record therefore supports interpretation of the listed outcomes, rather than conclusions about every proposed effect of the device.

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

Reasons for not completing this period:

Analysis population for the primary outcome, as defined in the registry: The outcome was the ability to complete the initial set of aligners

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 Ability to Complete Treatment Aligners in Conjunction With an Active and Placebo Vibration Device (AcceleDent® Aura), measured over 6 months.

The primary endpoint records whether participants were able to complete the initial set of aligners during treatment with either an active or placebo vibration device. The registry describes a 6-month timeframe and says participants in both groups were asked to change aligners each week. The arm results are counts of participants: 10 of 13 in the active-device group and 11 of 13 in the control-device group were recorded as completing the aligner series.

This endpoint is a binary outcome at the participant level: each participant is classified according to whether the initial aligner series was completed. Counting participants makes the endpoint directly interpretable as completion events within each group. The registry description mentions tracking the percentage able to complete the series, while the posted outcome values are presented as participant counts. No separate timing measure for completion, definition of successful completion beyond the stated ability to complete the series, or account of participants with unknown completion status is reported in the registry record.

Completion is the primary endpoint named in the registry, so it is the main posted basis for comparing the groups. It is not identical to a direct measurement of tooth movement speed, overall treatment duration, pain, discomfort, or final alignment. Those questions require outcomes that measure them explicitly. The secondary endpoint concerns final alignment scores of the upper and lower incisors; it addresses a different aspect of treatment and should be interpreted separately from the completion count.

7. Results Posted in the Registry

• A (Active Device): 76.9% (10/13) versus 84.6% (11/13) on control; risk difference -7.7 percentage points (95% CI -37.8 to 22.5), risk ratio 0.91 (0.62–1.33); unadjusted two-proportion z-test p = 0.619.

8. Secondary Efficacy Endpoints

The registry also posts results for secondary outcomes. For each outcome below, the endpoint type, the test applied to the posted summary statistics, the result and its interpretation are given in turn. Secondary endpoints are usually not adjusted for multiple testing, so they support rather than confirm the primary finding.

Final Alignment Scores of the Upper and Lower Incisors

• Endpoint type: Continuous: a mean value per participant, compared as a difference in means.
• Test: Unadjusted two-sample z-test for the difference in means, using the posted standard deviations.
• Result:
  • A (Active Device): mean 2.20 versus 2.10 on control; difference 0.10 (95% CI -0.48 to 0.68), standardized effect d = 0.13; z-test p = 0.735.
• Interpretation:
  • The 95% confidence interval includes no difference, so these data do not show a statistically significant difference between A (Active Device) and the control. The interval gives the range of effects that remain compatible with the data.

The registry lists one posted secondary endpoint: final alignment scores of the upper and lower incisors at 6 months, measured with Little's irregularity index in millimeters. The group means are close, and the mean-difference confidence interval includes zero. The result therefore does not show a clear separation between the groups on this secondary measure. It also does not rule out differences in either direction, given the uncertainty around the estimate.

The secondary outcome addresses final alignment scores, whereas the primary endpoint records completion of the initial aligner series. They are related to the broader treatment process but are not interchangeable measures. A participant's ability to complete an initial aligner series does not, by itself, determine a final alignment score, and a final score does not directly measure completion or treatment speed. The secondary finding therefore adds context but does not confirm or overturn the primary comparison.

The secondary p-value is unadjusted. When several outcomes are examined, the chance of seeing an apparently notable result by chance can increase. Without a reported multiplicity plan, an unadjusted secondary result should be treated as exploratory and interpreted with restraint, rather than as independent confirmation of a treatment effect. The registry record does not describe a hierarchy for the primary and secondary outcomes or report an adjustment for multiple comparisons.

The pattern across the posted endpoints is that neither comparison gives a precise separation between the groups. That shared uncertainty is more informative than treating one outcome as a decisive verdict on the other. The record does not report additional secondary analyses or a prespecified framework for combining the endpoints, so the endpoints should remain distinct in interpretation.

Secondary outcomes registered for this trial, for reference (only those above were recalculated):

• Final Alignment Scores of the Upper and Lower Incisors

9. Statistical Interpretation

10. Statistical Methods Explained

The registry identifies the study as randomized and parallel-group. In a randomized trial, allocation is intended to make the comparison groups similar, on average, with respect to factors that could influence outcomes. Randomization does not guarantee that small groups will be balanced on every characteristic. Details of the allocation sequence and concealment are not reported in the registry record, so the implementation of randomization cannot be assessed from the posted information alone.

What does the primary comparison estimate?

The primary outcome is a count of participants who completed the initial aligner series. The comparison reports a risk difference for the active device versus the control device. In general, a risk difference subtracts the event proportion in one group from the event proportion in the other, using the order specified for the comparison. A value below zero in this comparison indicates that the observed event proportion was lower in the active group than in the control group. The posted estimate is negative, consistent with the counts of 10 and 11 completions among 13 participants in the respective groups.

The comparison also includes relative measures, a risk ratio and an odds ratio. In general, a risk ratio compares event proportions between groups, while an odds ratio compares event odds. These measures express the comparison on different scales; they do not replace the absolute group counts. The registry supplies estimates and confidence intervals for both relative measures, but the small sample means those intervals are broad. The particular method used to calculate each interval is not reported in the registry record.

How should the p-value be read?

The primary unadjusted p-value is 0.619. In general, a p-value evaluates how compatible observed data are with a specified null hypothesis under a statistical model. A larger p-value does not prove that the null hypothesis is true, and a smaller p-value would not by itself establish that an effect is important. Interpretation also depends on the size and precision of the estimate, the design, and whether the analysis was planned in advance. The registry does not identify the test used for the posted primary comparison or report a prespecified analysis plan.

The word unadjusted means the listed p-value is not presented as adjusted for multiple comparisons or for covariates. The registry does not report a model adjusting for participant characteristics. The posted estimate should therefore be understood as a simple group comparison rather than as a covariate-adjusted treatment estimate. The precise calculation and inferential method are not reported in the registry record.

What does the secondary mean difference describe?

The secondary endpoint is a continuous measure: Little's irregularity index, in millimeters, for final alignment scores of the upper and lower incisors at 6 months. The registry reports a group mean and standard deviation for each arm, plus an unadjusted mean difference and confidence interval. In general, a mean difference expresses the difference between group averages in the measurement's original units. A standard deviation describes the spread of individual observations around a group's mean; it is not the uncertainty interval for the mean difference.

The secondary comparison's interval extends across zero, and its unadjusted p-value is 0.735. This means the posted data are compatible with differences in either direction as well as little or no difference. No adjustment for other variables or for multiple outcome testing is reported. The method used for the mean-difference interval and test is not reported in the registry record.

Why do over-dispersion and model choice matter?

General statistical context: for count or binary outcomes, an analysis relies on assumptions about how observations vary around the model's expectations. Over-dispersion means that observed variation is greater than the model expects. If it is ignored, standard errors can be too small and confidence intervals too narrow, making results appear more precise than they are. The primary endpoint is binary at the participant level, but the registry does not report a model, a dispersion assessment, or an over-dispersion adjustment. No claim can therefore be made about whether such a check was undertaken.

The secondary endpoint is continuous, and its reported standard deviations differ between the arms. That feature can matter when selecting a method for comparing means, but the registry does not identify the method used or describe any checks of its assumptions. The posted estimates can be described, while the analysis procedure remains undocumented.

What do the planning illustrations represent?

The registry includes sample-size planning illustrations calculated from the observed effects, rather than from the trial's original design assumptions. They use a two-sided significance level of 0.05, equal allocation between the two arms, and a normal approximation; the effect to detect is a stated share of the observed effect. The listed participant counts are planning quantities. They should not be confused with the number enrolled or the number with posted outcome data.

These calculations are sensitive to the observed effect used as their starting point. A pilot estimate based on a small group can be unstable, so an illustration built from that estimate is not a guarantee that a future study would have the same effect or require exactly the listed number. The original trial's sample-size justification and design assumptions are not reported in the registry record. The illustrations are not observed power calculations.

11. Confidence Intervals and Precision

Precision concerns how narrowly the data locate an effect estimate. The primary comparison's risk-difference confidence interval is broad and includes zero. It therefore does not isolate a single direction or a narrow range of plausible differences. The observed counts are close, but the small number of participants means that the estimate remains uncertain; the counts alone should not be treated as proof of equivalence.

A confidence interval is a range generated by a statistical procedure to express uncertainty around an estimate. In general, narrower intervals indicate greater precision, while wider intervals indicate less precision. The confidence level and calculation method for the posted intervals are not reported in the registry record. The interval can still be read in relation to zero: the primary interval spans negative and positive risk differences, so it is compatible with effects in either direction as well as no difference.

The secondary mean-difference interval also spans zero. Its point estimate is close to zero, but the interval includes differences on both sides. Thus, the secondary estimate is also not precise enough to establish a clear group separation. The listed standard deviations describe variability among individual scores; they should not be mistaken for confidence intervals around the group comparison.

The comparison statistics should be considered in light of the small outcome groups. Wider uncertainty is expected when the data contain limited information, especially for outcomes recorded as participant counts. More participants could narrow uncertainty in a future study if other features of the design and outcome measurement were suitable, but the registry record does not establish what sample size or design would be sufficient.

The absence of a clearly separated estimate is not the same as evidence that the treatment groups are identical. Conversely, an estimate in one direction does not establish a real effect when its interval remains broad. Precision is therefore central to interpretation: the posted point estimates describe the observed data, while the intervals show that the underlying group differences remain uncertain.

12. Planning a Similar Trial: Sample Size

This is a planning illustration, not a re-evaluation of the original trial. It asks: if a new study wanted to detect a difference like the one observed, or a smaller one, how large would it need to be? It is deliberately not “observed power” of the finished trial, which is not a meaningful quantity.

The planning illustrations are expressed as participants per arm, not as a total across both arms and not as total events. For the binary completion outcome, the listed participant counts per arm range from 411 and 550 when planning for the full observed effect, to 704 and 941 when planning for 75% of the observed effect, and 1,518 and 2,032 when planning for 50% of the observed effect. In each pair, the first figure corresponds to 80% power and the second to 90% power.

For the continuous secondary outcome, the corresponding figures per arm are 894 and 1,196 for the full observed effect, 1,588 and 2,126 for 75% of the observed effect, and 3,573 and 4,783 for 50% of the observed effect. Again, the first figure is for 80% power and the second for 90% power. In plain language, a design with 80% power has a stated probability of detecting the effect used in the calculation if that effect is truly present, under the calculation's assumptions. The 90% column uses a higher target probability of detecting that effect.

The assumptions listed for these illustrations are a two-sided significance level of 0.05, equal allocation between the two arms, and a normal approximation. Each calculation uses the stated share of the observed effect as the effect to detect. Smaller effects require more participants to detect under the same general assumptions, which is why the counts increase when planning for 75% or 50% of the observed effect.

These are planning illustrations derived from the observed effect, not the trial's original sample-size justification; that justification is not reported in the registry record. This is not observed power. It is a forward-looking calculation that illustrates how sample-size requirements change under the listed assumptions, not a measure of whether the completed trial had enough power.

13. How the Sample Size Is Derived

Power is the probability that a study of a given size rejects the null hypothesis when a specific true effect exists. It depends on four things: the effect to detect, the variability of the outcome, the significance level (here a two-sided α of 0.05, so z_1−α/2 = 1.960) and the desired power (z_1−β = 0.842 for 80% and 1.282 for 90%).

Formula

n is the number of participants in each arm, p₀ and p₁ are the control and treatment proportions, and p̄ is their average.

Worked calculation for this trial

1. Control proportion p₀ = 0.846; treatment proportion p₁ = 0.769; average p̄ = 0.808.
2. First term: z_1−α/2 × √[2p̄(1−p̄)] = 1.96 × 0.5574 = 1.0924.
3. Second term: z_1−β × √[p₀(1−p₀) + p₁(1−p₁)] = 0.842 × 0.5547 = 0.4668.
4. n = (1.0924 + 0.4668)² / (-0.0769)² = 410.9, rounded up to 411 participants per arm for 80% power.

The smaller-effect rows in the table above repeat the same calculation with the effect multiplied by 0.75 and 0.5 (for ratios, applied to the logarithm of the ratio).

R code

alpha <- 0.05
z_a   <- qnorm(1 - alpha / 2)          # two-sided
p0 <- 0.846153846153846                          # control proportion
p1 <- 0.769230769230769                          # treatment proportion
n_per_arm <- function(power, frac = 1) {
  q1 <- p0 + (p1 - p0) * frac               # smaller effect = fraction of the observed difference
  pbar <- (p0 + q1) / 2
  z_b <- qnorm(power)
  ceiling(round((z_a * sqrt(2 * pbar * (1 - pbar)) + z_b * sqrt(p0 * (1 - p0) + q1 * (1 - q1)))^2 / (q1 - p0)^2, 6))
}
for (f in c(1, 0.75, 0.5))
  cat(sprintf("%3.0f%% of observed effect: n per arm = %s (80%% power), %s (90%% power)\n", 100 * f,
              format(n_per_arm(0.80, f), big.mark = ","), format(n_per_arm(0.90, f), big.mark = ",")))

# Check against R's built-in function (unrounded n per arm)
cat("power.prop.test:", round(power.prop.test(p1 = p0, p2 = p1, power = 0.80)$n, 1), "\n")

# Simulation: how often does the z-test reject at the 80%-power sample size?
set.seed(2438280)
n    <- n_per_arm(0.80)
reps <- 20000
x0 <- rbinom(reps, n, p0); x1 <- rbinom(reps, n, p1)
ph <- (x0 + x1) / (2 * n)
z  <- ((x1 - x0) / n) / sqrt(ph * (1 - ph) * 2 / n)
cat(sprintf("Simulated power at n = %s per arm: %.3f (%d replicates)\n", format(n, big.mark = ","), mean(abs(z) > z_a, na.rm = TRUE), reps))

Output from running the code

100% of observed effect: n per arm = 411 (80% power), 550 (90% power)
 75% of observed effect: n per arm = 704 (80% power), 941 (90% power)
 50% of observed effect: n per arm = 1,518 (80% power), 2,032 (90% power)
power.prop.test: 410.9 
Simulated power at n = 411 per arm: 0.802 (20000 replicates)

The simulation draws many pairs of event counts at the planned sample size and counts how often the two-proportion z-test rejects the null. It should land close to the target power; at very small required sample sizes it can fall below it, because the normal approximation is rough there.

14. Multiplicity, Missing Data and Analysis Populations

Multiplicity arises when an analysis considers more than one outcome, comparison, time point, or statistical test. If each is assessed without adjustment, the chance of at least one apparently unusual result can increase. General statistical practice therefore often specifies in advance which outcome is primary, how secondary outcomes will be treated, and whether adjustments will be made. The registry identifies a primary endpoint and lists a secondary endpoint, but a multiplicity strategy is not reported in the registry record.

The posted primary and secondary comparisons have unadjusted p-values. No correction for multiple testing is reported, and the registry does not state whether the secondary endpoint was intended to be confirmatory or exploratory. The secondary result consequently carries less weight as confirmatory evidence than a result supported by a prespecified analysis plan and an appropriate multiplicity strategy. This does not invalidate the descriptive result; it limits how strongly it should be interpreted.

The handling of missing data is also not reported in the registry record. The outcome counts show 13 participants in each group, while the registry enrollment is 27. The record does not explain whether every enrolled participant contributed to each outcome, whether anyone withdrew, whether any measurements were unavailable, or how incomplete observations were treated. It would be inappropriate to assume that missing observations did not occur or to infer how they were handled.

The analysis population is not described. The record does not say whether the comparisons followed an intention-to-treat approach, included only participants who completed treatment, or used another population definition. No protocol deviations or exclusions are detailed. These omissions make it difficult to assess whether the posted comparisons preserve the randomized groups as intended or whether exclusions could have affected the results.

Details of the statistical analysis plan, including the planned test, interval method, covariate adjustment, and any interim analyses, are not reported in the registry record. The result can be interpreted as posted, but the absence of these details limits assessment of whether the analysis followed a prespecified plan.

15. 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 reports zero serious adverse events and zero other adverse events in the active-device group, with 13 participants at risk. It also reports zero serious adverse events and zero other adverse events in the control-device group, with 13 participants at risk. No deaths are recorded in either group. These are event counts recorded for the listed groups; they do not establish that no adverse events could occur.

Safety counts are most informative when read alongside the number of participants followed, the length and completeness of follow-up, and the definitions used for each event category. The registry gives the at-risk group counts and lists a 6-month timeframe for the primary and secondary outcomes, but it does not provide detailed adverse-event definitions or explain how safety events were collected. Follow-up completeness for safety is not reported in the registry record.

With small groups, zero recorded events provide limited information about uncommon events. They describe what was recorded in this trial, not a guarantee about experience in a larger population or over a different period. The safety figures should therefore be interpreted as descriptive registry counts, without extending them beyond the trial's recorded participants and reported follow-up.

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

The primary result shows that the posted completion counts were similar in the two groups, with one fewer participant recorded as completing the aligner series in the active-device group than in the control group. The unadjusted risk-difference estimate is negative, but its confidence interval includes zero and spans both negative and positive values. The unadjusted p-value is 0.619. The data therefore do not establish a clear difference in completion between the device groups, while remaining too imprecise to demonstrate that the groups are equivalent.

This result concerns the ability to complete the initial set of aligners by the stated 6-month timeframe. It does not directly measure how quickly individual teeth moved, total treatment duration, pain, discomfort, or long-term treatment outcomes. Although the background description discusses proposed effects on bone remodeling and discomfort, those concepts are not the primary endpoint. A conclusion about an outcome requires data that measure that outcome.

The secondary endpoint concerns final alignment scores of the upper and lower incisors. Its estimate and interval also leave substantial uncertainty, and it is not a substitute for the primary completion outcome. The registry does not report a multiplicity plan, missing-data approach, or detailed analysis plan, all of which affect how firmly the posted estimates can be interpreted.

The trial is a pilot with 13 participants recorded per group for the primary outcome. Its estimates can describe what happened among those recorded participants and can illustrate the uncertainty of a small study. They should not be treated as a precise prediction of results in a larger study. The planning illustrations are based on observed effects and are not evidence that the trial achieved a particular power.

The safety record lists no adverse events or deaths in either group, but the small number of participants and lack of detail about safety ascertainment limit what those counts can establish. Overall, the posted results are informative as a preliminary comparison, not as a definitive answer about the device's effects across all outcomes described in the background rationale.

17. Why This Trial Matters Statistically

This trial illustrates why a group comparison should be read through both its estimate and its uncertainty. The primary counts differ by one participant, but the confidence interval is broad and crosses zero. Focusing only on the point estimate could overstate what the data establish; focusing only on the p-value would also miss the range of differences still compatible with the observations.

The pilot scale is important. With 13 participants recorded in each group, the study offers limited information for distinguishing a modest effect from chance variation. This is especially relevant for binary outcomes, where each participant contributes a completion or non-completion observation. A small count can make estimates unstable and intervals wide, even in a randomized design.

The record also demonstrates the importance of distinguishing a primary outcome from related but different measurements. Completing an aligner series, final alignment scores, treatment duration, and discomfort answer different questions. A result for one should not be generalized to the others without direct outcome data. The registry names a completion endpoint and an alignment-score endpoint, while the background describes additional proposed benefits.

Finally, a pilot's observed effect can be a fragile basis for planning. The registry's planning illustrations show that assumed effect size has a substantial influence on the participant counts needed under the stated assumptions. Those illustrations are not the original design justification and are not observed power. The trial is statistically useful as an example of the value of transparent uncertainty, explicit outcome definitions, and careful separation of exploratory findings from confirmatory evidence.

18. 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.

The limited number of participants is a central limitation. The registry lists enrollment of 27, while the primary outcome has 13 participants recorded in each arm. The brief description says the study would include 12 participants per group. These figures are not fully reconciled in the record, and the reason for the difference is not reported in the registry record. The outcome counts alone do not explain what happened to the remaining enrolled participant or the difference from the described group size.

The posted comparisons are imprecise, with confidence intervals that include zero. The registry does not provide the original sample-size justification, so it is not possible to assess the planned detectable effect from the record. The displayed planning illustrations instead use the observed effects and stated assumptions.

Important design and analysis details are absent. The record does not describe allocation concealment, the specific masking roles, the statistical tests, the confidence-interval methods, missing-data handling, analysis populations, protocol deviations, or any interim analyses. It lists quadruple masking, while the brief description calls the trial triple-blind; the discrepancy is not explained in the registry record. The specific vibration settings used in the active and sham devices are also not reported.

The primary endpoint captures completion of an initial aligner series, not direct tooth-movement speed or overall treatment duration. The trial description says participants changed aligners weekly, but the posted primary outcome does not provide a direct comparison of treatment time. The listed secondary outcome measures alignment scores, while pain and discomfort are discussed as product claims rather than posted outcomes in the registry record. These distinctions limit the claims that can be made from the posted endpoints.

The safety counts are zero in both groups, but detailed event definitions and safety follow-up completeness are not described. The small sample and limited registry entries leave uncertainty about both efficacy outcomes and safety beyond the events recorded.

19. Related Tutorials

20. Related Statistical Calculators

21. Sources

• ClinicalTrials.gov: Accelerated Tooth Movement With AcceleDent® and Aligners - a Pilot Project — NCT02438280.
• Registry record last updated 2018-10-30; status last verified 2018-09.
• Results first posted 2018-08-21.
• 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.

22. Record Summary

NCT02438280 is a completed randomized, parallel-group pilot sponsored by the University of Washington. It compares an active AcceleDent device with a sham device during aligner treatment. Both groups were instructed to use their assigned device for 20 minutes each day and change aligners weekly. The registry lists quadruple masking; the brief description calls the study triple-blind.

The primary outcome was completion of the initial aligner series at 6 months. The registry records 10 completions among 13 participants in the active group and 11 among 13 in the control group. The unadjusted comparison has a negative risk-difference estimate, a confidence interval that includes zero, and a p-value of 0.619. The one posted secondary endpoint is final alignment scores, with an unadjusted p-value of 0.735.

Zero serious adverse events, zero other adverse events, and zero deaths are recorded in each group. The registry does not report detailed analysis methods, missing-data handling, or the original sample-size justification. The posted comparisons are therefore best read as preliminary, imprecise findings from a small pilot.