Amnion-Chorion Allograft Barrier Used for Root Surface and Guided Tissue Regeneration: Complete Statistical Analysis

1. Trial at a Glance

This page covers the registry results for Amnion-Chorion Allograft Barrier Used for Root Surface and Guided Tissue Regeneration (NCT03095976), a na na study. The primary outcome is Probing Depth Change.

2. Clinical Question

3. Trial Design

NCT03095976 is a completed, single-group pilot project evaluating an Amnion-Chorion allograft membrane in a combination guided tissue regeneration treatment for periodontal intrabony and furcation defects. The intervention description specifies membrane application on the root surface, together with corticocancellous allograft bone substitute covered by the membrane. The registry lists Indiana University as the sponsor.

The study enrolled 4 participants. The record identifies one test group and gives no randomized allocation; it also lists no masking. With no separate comparator arm, this design can describe outcomes observed after the procedure but cannot estimate a treatment contrast against a control condition. In particular, any change from baseline would not by itself distinguish the procedure's contribution from other influences, including natural variation or other care.

The study is marked completed. Its start date is 2017-06-14, and its primary completion date is 2019-09-10. The registry lists the phase as NA. The primary outcome is probing-depth change, described as a continuous measure summarized by a mean and standard deviation, at baseline and 6 months. Numerical primary outcome results are not reported in the registry record. The record lists two outcome measures, but only the primary measure is described in the available outcome details; further details about the other outcome are not reported in the registry record.

The registry does not report a protocol-level sample-size justification, the eligibility criteria in detail, participant characteristics, or the statistical analysis plan. Those omissions limit assessment of how the study was designed to answer its clinical question and how representative the enrolled group may be.

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 Probing Depth Change, measured over Baseline and 6 months.

Probing depth is a continuous clinical measurement recorded at the intrabony defect. The registry describes the primary endpoint as probing-depth change, measured at baseline and 6 months, with probing depth assessed following the surgical procedure. The unit is millimeter, and the stated summary is a mean with standard deviation.

In general, a change endpoint compares measurements taken at two time points to describe how the measured depth changes over follow-up. A mean summarizes the average measurement or change in a group; a standard deviation describes how dispersed individual observations are around that average. These summaries answer different questions: the mean concerns the group average, while the standard deviation concerns variability among observations.

Probing depth is used as a measure related to the periodontal defect being treated. The registry record does not report the numerical baseline measurement, the 6-month measurement, the mean change, its standard deviation, or the number of participants with endpoint data. As a result, the endpoint's observed direction, magnitude, and precision cannot be assessed from the posted efficacy results. The record also does not provide a definition of how change was calculated or whether measurements were averaged across sites. Those details are not reported in the registry record.

7. Why No Re-analysis Is Shown

8. Statistical Interpretation

9. Statistical Methods Explained

What does a mean and standard deviation describe?

The primary outcome is continuous and is specified as a mean with standard deviation. In general, the mean represents the average value in the analyzed group. The standard deviation describes how much individual values vary around that average. A mean alone does not show whether individual measurements are tightly clustered or widely spread, while a standard deviation does not convey the average direction of change.

For a change outcome, interpretation depends on the definition of the change and the time points used. The registry names baseline and 6 months and states that probing depth was measured at the intrabony defect following surgery. It does not report the values or a detailed calculation rule. The record therefore does not allow a reader to reconstruct the change estimate or assess whether the reported summary, if any, used all enrolled participants.

What would a confidence interval add?

In general, a confidence interval expresses the uncertainty around an estimated quantity under the assumptions of the analysis. It gives a range of values compatible with the observed data and the chosen method; it is not a guarantee that the true value lies in that range. A narrower interval indicates greater precision than a wider interval, all else being equal. No confidence interval for the primary endpoint is reported in the registry record, so precision cannot be evaluated through this measure.

A p-value, if reported, would address compatibility between data and a specified statistical model under a null hypothesis. It would not state the probability that the treatment is effective, and it would not substitute for an estimate of the size and precision of an effect. The registry record lists zero analyses and does not report a p-value or an inferential test for the primary outcome. The statistical analysis plan, including any model or test intended for this endpoint, is not reported in the registry record.

Why does the single-group design matter?

In general, a control group helps distinguish changes associated with an intervention from changes that could occur for other reasons. This study is listed as single-group, with no randomized allocation and no like-for-like control comparison. A baseline-to-follow-up description, if available, would not provide the same evidence as a randomized treatment contrast. It could show what was observed among participants receiving the combined procedure, but would not isolate the effect attributable to that procedure.

There is also no way to separate the effect of the membrane from the effect of the bone substitute or other aspects of the treatment package using the described design. That would require comparisons that the registry record does not describe. The record does not report any adjusted model that might address differences in other measured characteristics, nor does it report an analysis population or adjustment variables.

How should planning calculations be read?

In general, a sample-size planning calculation estimates the number of participants that might be needed to detect a specified effect under stated assumptions. It is not an observed result and does not show that a study had a given probability of detecting its actual effect. The planning assumptions listed for the illustrations are a two-sided significance level of 0.05, equal allocation between two arms, and a normal approximation. The target effect is described as a stated fraction of the observed effect. These assumptions describe planning illustrations, not the design of this single-group pilot.

The illustrations are explicitly based on an observed effect, but the registry record does not provide a numeric primary outcome effect. The protocol's own sample-size justification is not reported in the registry record. Accordingly, planning figures should not be read as the original enrollment rationale or as observed power. A calculated number of participants for a hypothetical two-arm comparison would not change the fact that this study enrolled one group and had no comparator.

What remains unknown about analysis?

The record lists two outcome measures but zero analyses. It does not report an analysis plan, any interim analyses, handling of missing measurements, adjustment for multiple outcomes, or the population used for analysis. These omissions prevent assessment of whether outcome choices and analytic decisions were specified before results were known. They also prevent evaluation of whether any reported result might be sensitive to missing observations or alternative analysis choices.

General statistical interpretation should therefore remain modest: the registry identifies the outcome concept, time point, summary measure, and treatment group, but it does not provide the endpoint estimates or analysis details needed to assess uncertainty, statistical evidence, or robustness.

10. Confidence Intervals for Each Arm

No two-arm comparison is shown for this trial, but each arm's mean can be given with a t-based 95% confidence interval computed from the posted mean, spread and number of participants.

R code and output

arm <- c("Test Group")
n   <- c(4)
m   <- c(4.22)
sp  <- c(0.73)
sd  <- sp      # posted standard deviations
for (i in seq_along(n)) {
  se <- sd[i] / sqrt(n[i]); h <- qt(0.975, n[i] - 1) * se
  cat(sprintf("CARM|%s|%d|%.3f|%.3f|%.3f|%.3f\n", arm[i], n[i], m[i], sd[i], m[i] - h, m[i] + h))
}

CARM  Test Group  4  4.220  0.730  3.058  5.382

11. Multiplicity, Missing Data and Analysis Populations

The registry lists two outcome measures, but detailed information is available for only the primary endpoint. The other outcome's definition, time point, and analysis are not reported in the registry record. The record lists zero analyses and does not describe whether a multiplicity strategy was planned or used.

In general, multiplicity arises when several outcomes or hypotheses are tested. Examining multiple results can increase the chance of finding an apparently notable result by chance, so a statistical plan may specify which outcome is primary and how additional tests will be interpreted. The primary endpoint is identified as probing-depth change, but the registry record does not report a full testing plan or adjustments for multiple comparisons. It is not possible to determine from the record whether multiplicity was considered.

The registry record does not report the number of participants with usable baseline and follow-up measurements, whether any observations were missing, or how missing data were handled. It also does not identify an intention-to-treat, per-protocol, or other analysis population. In general, missing follow-up data can affect both the estimate and its uncertainty, particularly when the reason for missingness is related to participants' outcomes. Without participant-flow and missing-data details, the completeness of the endpoint analysis cannot be assessed.

These are reporting gaps, not evidence that a particular analytic choice was or was not made. The protocol-level statistical plan, interim-analysis approach, missing-data procedure, and analysis populations are not reported in the registry record.

12. 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 5% reporting threshold.

The registry lists the test group with 4 participants at risk for serious adverse events and 0 affected. It also lists 4 participants at risk for other adverse events and 0 affected. Deaths are listed as 0. No serious adverse-event terms are listed.

These figures are counts recorded for the study group, not estimates comparing the procedure with another treatment. With a single group, the record cannot provide a relative safety comparison against a control. The counts also apply to the recorded study and should not be treated as proof that an event cannot occur. A small enrolled group offers limited information about uncommon events, and the registry record does not provide detailed event definitions, follow-up completeness, or additional safety analyses.

Zero reported events means that the registry lists none in these categories for the participants at risk; it does not imply zero risk in other patients or in other settings. The record does not report further details on ascertainment or the duration over which adverse events were collected. Safety figures should therefore be read as descriptive counts, separate from the unreported primary efficacy result.

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

This study record documents a pilot evaluation of a combined periodontal regeneration procedure and identifies probing-depth change at baseline and 6 months as its primary outcome. It also records enrollment of 4 participants, one test group, and no randomized allocation. These registry entries describe the scope and structure of the study, but they are not a numerical estimate of treatment effect.

The primary endpoint results are not reported in the registry record. Therefore, the posted efficacy information does not establish whether probing depth changed, how large any change was, how variable it was among participants, or how precisely it was estimated. The missing numerical result should not be recast as either a favorable or unfavorable result.

Even if a within-group change were reported, the absence of a control group would limit causal interpretation. General changes over time, measurement variability, and other aspects of care could contribute to an observed before-and-after pattern. The combined intervention also prevents attribution of any observed response to a single treatment component based on this design alone.

The record does show that no serious adverse events, other adverse events, or deaths are listed for the 4 participants at risk. Those descriptive counts provide limited safety information and do not establish comparative safety or exclude uncommon harms. Taken together, the registry entry describes a completed, small pilot with an outcome specified but no posted numerical efficacy analysis. It does not support a quantified conclusion about clinical benefit or comparative effectiveness.

14. Why This Trial Matters Statistically

Statistically, this trial is useful for illustrating the difference between an outcome being named and an outcome being reported with interpretable estimates. The record specifies a continuous primary endpoint, a measurement unit, a summary approach, and a follow-up time point. Yet without the mean change, standard deviation, participant count for the endpoint, or uncertainty interval, readers cannot assess the observed pattern or its precision.

The single-group structure is also central. In general, a control group supports estimation of a treatment contrast, whereas a single-group study describes observations within participants who receive the intervention. The registry explicitly lists no randomized allocation and no like-for-like control comparison. This limits what can be concluded even if a within-group change is available elsewhere.

The small enrollment of 4 makes careful separation of descriptive counts from broader inference particularly important. The registry does not report a sample-size justification, so it is not possible to judge whether enrollment was planned for a particular precision or hypothesis test. The planning illustrations are based on stated assumptions and an observed effect; they are not the study's original design rationale or observed power.

The record also makes visible important reporting questions: which participants contributed endpoint data, how missing measurements were treated, what analysis population was used, and whether multiple outcomes were addressed in a prespecified plan. These details are not reported in the registry record. Their absence limits the reproducibility and critical appraisal of the statistical analysis. The example therefore underscores that trial status, outcome labels, and event counts do not replace transparent reporting of estimates, uncertainty, and analysis methods.

15. 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 most direct limitation of this registry record is that it does not report numerical results for the primary probing-depth outcome. Without the endpoint estimate and its variability, neither the size of change nor its precision can be evaluated. The record also does not report the number with observed endpoint data or provide participant-level flow through follow-up.

The study enrolled 4 participants and used a single group, with no randomized allocation or control arm. This design cannot provide a treatment comparison, and observed changes would not by themselves establish that the intervention caused them. Because the procedure combines membrane placement with bone substitute, the separate contribution of each component also cannot be identified from the described group.

Participant characteristics and detailed eligibility criteria are not reported in the registry record, limiting assessment of applicability beyond the enrolled group. The record names periodontal intrabony and Grade II furcation defects in the study purpose, while the primary outcome description specifically locates probing-depth measurement at an intrabony defect. Further detail on the analyzed sites and measurement procedure is not reported.

The statistical analysis plan, sample-size justification, interim analyses, missing-data methods, and analysis population are not reported in the registry record. The record lists two outcome measures but gives detailed information for only the primary endpoint and lists zero analyses. The generalizability and completeness of the outcome assessment therefore remain difficult to judge. These limitations concern what can be assessed from the registry entry and do not establish what was or was not conducted outside the information recorded.

16. Related Tutorials

17. Related Statistical Calculators

18. Sources

• ClinicalTrials.gov: Amnion-Chorion Allograft Barrier Used for Root Surface and Guided Tissue Regeneration — NCT03095976.
• Registry record last updated 2021-04-14; status last verified 2021-03.
• Results first posted 2021-04-14.
• 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.

19. Record Summary

NCT03095976 is a completed, single-group pilot sponsored by Indiana University. It enrolled 4 participants and evaluated Amnion-Chorion allograft membrane used on the root surface with corticocancellous allograft bone substitute covered by the membrane in guided tissue regeneration for periodontal defects. No randomized allocation or comparator group is listed.

The primary endpoint is probing-depth change at an intrabony defect, measured at baseline and 6 months and described as a mean with standard deviation. Numerical efficacy results and analysis details are not reported in the registry record. The test group lists 0 serious adverse events, 0 other adverse events, and 0 deaths among 4 participants at risk in each adverse-event listing. These counts are descriptive and do not provide a comparative safety estimate.