Effects of AMP Application After Non-surgical Periodontal Therapy on Treatment of Periodontitis: Complete Statistical Analysis

1. Trial at a Glance

This page covers the registry results for Effects of AMP Application After Non-surgical Periodontal Therapy on Treatment of Periodontitis (NCT05530252), a randomized phase 4 study. The primary outcome is Periodontal Probing Depth.

2. Clinical Question

3. Trial Design

This was a completed, randomized, single-masked, parallel-group Phase 4 clinical trial sponsored by Beijing Stomatological Hospital, Capital Medical University. The registry lists an enrollment of 51. The study began on 2022-09-05 and had a primary completion date of 2022-12-30. The registry record does not identify who was masked or describe the masking procedure, sequence generation, or allocation concealment.

Three treatment regimens were studied. The AMP Group received SRP and subgingival antimicrobial peptide gel. The Perio Group received SRP and subgingival minocycline hydrochloride ointment. The SRP Group received SRP alone. This design allows the posted outcome summaries for the two adjunctive regimens to be considered alongside the summary for SRP alone, but the registry does not report formal comparisons among these groups.

The primary outcome was change from baseline in periodontal probing depth at 90 days. The registry reports 16 participants in each group for this outcome. It also states that three subjects did not return to the clinic as required and were excluded from final data analysis. The record does not explain the accounting between the enrollment figure, these exclusions and the outcome analysis groups.

Although the trial is marked completed, completion status alone does not establish that every planned outcome or analysis was reported. The registry lists three outcome measures, but only the primary endpoint is described in the posted results used for this interpretation; no secondary results are posted. The protocol, recruitment details, and a fuller account of trial procedures 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

Reasons for not completing this period:

Analysis population for the primary outcome, as defined in the registry: Three subjects did not return to the clinic as required and were not included in the final data analysis of the 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 Periodontal Probing Depth, measured over Change from Baseline Periodontal probing depth at 90 days.

Periodontal probing depth is the distance from the gingival margin to the bottom of the periodontal pocket. In this trial, it was assessed using a Williams periodontal probe. The primary endpoint is the change from baseline in probing depth at 90 days, measured in millimeters. The registry describes the summary parameter as a mean and lists the inter-quartile range as the dispersion measure.

Probing depth is used as a clinical measure of the periodontal pocket. Recording change from baseline focuses on how the measurement at follow-up differs from the participant’s starting measurement, rather than reporting only a follow-up value. The 90-day timeframe defines when the primary outcome was assessed; it does not describe longer-term outcomes.

The registry does not provide separate baseline values, participant-level measurements, or inter-quartile range values. It lists group means and accompanying lower and upper figures, but does not identify those figures as confidence intervals or state how they were calculated. The direction used to code change is also not explained. These omissions limit how fully the endpoint summaries can be interpreted and prevent treating the posted figures as a complete account of the distribution or uncertainty in the data.

7. Why No Re-analysis Is Shown

8. Statistical Interpretation

9. Statistical Methods Explained

What does randomization contribute?

Random assignment is intended to make treatment groups comparable, on average, with respect to factors that may affect an outcome. It can reduce systematic differences in treatment allocation, but it does not guarantee identical groups, especially in a study with a limited number of analyzed participants. The registry identifies the study as randomized but does not report how the random sequence was generated, whether allocation was concealed, or whether randomization was stratified. Those details are not reported in the registry record, so the implementation of randomization cannot be assessed from the posted information.

What does single masking mean in this record?

The design is labelled single-masked. Masking can reduce the influence of expectations on care or measurement, depending on who is masked and how the outcome is assessed. The registry does not say whether participants, clinicians, outcome assessors, or analysts were masked. Because periodontal probing involves an examiner taking a measurement, the identity and masking of the assessor would be relevant to judging the potential for measurement bias, but that information is not reported in the registry record.

How should the outcome summaries be read?

The primary result is described as a mean change in probing depth, in millimeters. A mean gives a central summary of the recorded values, but it does not show how those values are distributed among participants. The registry lists the inter-quartile range as the dispersion measure, which generally describes the spread of the middle half of observations. However, no inter-quartile range values are posted. The lower and upper figures accompanying each mean are not labelled with a measure or method, so their statistical interpretation is uncertain.

A confidence interval is a general statistical way to express uncertainty around an estimated quantity, such as a mean or a treatment contrast. Its interpretation depends on the method and on the quantity being estimated. The registry does not identify the posted lower and upper figures as confidence intervals, and it reports no confidence interval for a between-group contrast. Those figures therefore should not be used to infer the precision or statistical significance of a treatment comparison.

Where is the treatment comparison?

For a comparative trial, a direct estimate of the difference between groups is usually more informative than comparing separate group summaries. The estimate should be accompanied by an uncertainty measure and, when appropriate, a test of the stated hypothesis. None of these comparative results is reported for the primary outcome in the registry record. There are no posted p-values or descriptions of an adjusted or unadjusted analysis. The available group means can be described, but no new contrast should be inferred from them.

The record lists three outcome measures and zero posted analyses. It does not identify a statistical model, adjustment covariates, or a method for accounting for repeated measurements or clustering of periodontal sites within participants. Such choices can affect standard errors and inference in general, but the registry does not provide enough detail to determine whether any such structure was relevant to the reported analysis or how it was handled.

What does the planning illustration represent?

The registry’s sample-size assumptions describe a planning illustration based on the observed effect, with a two-sided significance level of 0.05, equal allocation between two arms, and a normal approximation. The effect to detect is described as a stated fraction of the observed effect. These are assumptions for an illustrative calculation, not a report of the trial’s original design rationale. The sample-size justification and statistical plan are not reported in the registry record.

Planning estimates answer a hypothetical question about the number of participants per arm that would be needed under specified assumptions. They do not describe the number actually analyzed, prove that a study had adequate power, or constitute observed power. When planning is based on an effect observed in the same study, the result depends on that estimate and should not be treated as an independent confirmation. The registry does not report a sample-size justification for this trial, and the planning assumptions should not be mistaken for its protocol.

What can be concluded from the posted methods information?

The registry supports a descriptive reading of the endpoint summaries and a basic account of the randomized, single-masked, parallel design. It does not provide enough statistical detail to reconstruct the analysis, evaluate its assumptions, or reproduce an inferential comparison. Important information—including the analysis population definition, missing-data method, assessor masking, and multiplicity strategy—is not reported in the registry record. General statistical principles can explain why these details matter, but they cannot fill in what the record leaves unspecified.

10. Multiplicity, Missing Data and Analysis Populations

The registry lists three outcome measures, but no secondary outcome results are posted. The primary endpoint is change from baseline in periodontal probing depth at 90 days. The record does not explain which outcomes were designated primary in the protocol, whether there were multiple time points or analyses, or whether a multiplicity adjustment was planned. A multiplicity strategy is not reported in the registry record. In general, when several outcomes or comparisons are tested, the chance of at least one apparently unusual result can increase; whether that issue applied to the planned analyses cannot be determined from the posted information.

The primary outcome description says that three subjects did not return to the clinic as required and were not included in the final data analysis. The record does not state whether those participants had any follow-up measurements, why they did not return, or whether their absence differed by treatment group. It also does not describe an imputation method, sensitivity analysis, or other approach to missing data. The outcome analysis lists 16 participants in each group, but the record does not explain the relationship between those analysis counts and the enrollment figure.

The analysis population is not identified as intention-to-treat, modified intention-to-treat, or per-protocol. Those labels describe different choices about which randomized participants are included and can affect the interpretation of a treatment comparison. Without a stated population definition and an account of exclusions, the posted means are best understood as summaries for the participants included in the final data analysis. Whether missingness or exclusions could have influenced the estimates cannot be assessed from the registry record.

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 reports safety counts separately for the AMP, Perio and SRP groups. For each group, 17 participants are listed as at risk for serious adverse events and 0 as affected. The same at-risk and affected counts are reported for other adverse events. Deaths are listed as 0 in each group, and no serious adverse event terms are listed.

These are registry-reported event counts, not proof that no adverse events occurred outside the categories or observation period captured in the record. The registry does not describe the safety follow-up duration, event-collection procedures, severity criteria, or whether adverse events were judged related to treatment. The primary outcome analysis lists 16 participants per group, while the safety counts list 17 at risk per group; the record does not explain this difference.

Zero reported events in a group does not establish that the true risk is zero. Event counts can be informative, but their interpretation depends on the number observed, the duration and completeness of follow-up, and how events were defined and collected. The posted figures support only the limited statement that the registry reports no affected participants and no deaths in the listed safety categories.

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

The result is a set of descriptive group summaries for change in periodontal probing depth at 90 days among participants included in the final data analysis. The registry reports a mean for each of the AMP, Perio and SRP groups, with 16 participants listed in each group. It also gives lower and upper figures alongside each mean, without identifying what those figures represent. The record notes that three subjects did not return to the clinic as required and were excluded from the final analysis.

The result does not provide a formal estimate of the difference between the AMP regimen and either comparator. It does not report a statistical test, a p-value, or an identified confidence interval for a treatment contrast. The coding direction of change is not described, and no separate baseline measurements are posted. These gaps mean that the group means should not be turned into claims about the size, direction, or certainty of a treatment effect.

Nor do the summaries establish whether any observed group difference is clinically important. Statistical evidence about a difference and its practical importance are distinct questions; neither can be settled from separate means alone. General interpretation would also depend on the variability of participant measurements, the analysis method, and the completeness of follow-up. The registry lists an inter-quartile range as the dispersion measure but does not give its values.

The findings are limited to the stated endpoint and 90-day assessment. No secondary outcome results are posted, and the record does not provide longer-term results. The reported safety counts are also limited to the registry’s listed adverse-event categories and do not establish the absence of unrecorded or later events. The information supports a description of what was reported, not a conclusion that one regimen works or fails, or that the observed pattern will apply to other populations or settings.

13. Why This Trial Matters Statistically

This trial raises a useful statistical question: how should a reader distinguish group summaries from evidence about a treatment contrast? The registry reports means for three treatment groups, but no formal comparison of those means. Separate summaries can describe each group; they do not, by themselves, quantify the uncertainty in a difference between groups or show whether the difference is compatible with chance variation.

The design also makes the analysis population important to interpretation. The record reports an enrollment of 51, says three subjects did not return and were excluded from final analysis, and lists 16 participants per group for the primary outcome. It does not explain how those figures relate to one another or define the population used for analysis. Clear accounting of participant flow and missing outcomes helps readers assess how closely a reported estimate reflects the randomized groups.

Another statistical issue is outcome reporting. Three outcome measures are listed, but secondary results and an analysis plan are not reported in the registry record. Knowing which outcomes and comparisons were planned, and how multiplicity was addressed, helps readers place reported results in context. The absence of those details does not prove that analyses were not conducted; it means the registry does not document them.

Finally, the distinction between a planning illustration and the trial’s actual design matters. The listed calculation assumptions are not a sample-size justification or evidence of observed power. Taken together, this record illustrates why transparent reporting of analysis methods, uncertainty, missing data, and prespecified outcomes is essential when interpreting a clinical trial.

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.

The registry record has several trial-specific reporting limitations. The primary outcome is defined as change from baseline at 90 days, but separate baseline values and the direction used to code change are not reported. The record lists inter-quartile range as the dispersion measure without posting inter-quartile range values. It also provides lower and upper figures beside each mean without identifying their statistical meaning.

Although the study is randomized and single-masked, the record does not describe sequence generation, allocation concealment, or who was masked. It does not report the statistical model, treatment-effect estimates, inferential tests, p-values, or confidence intervals for between-group comparisons. The analysis population and the approach to missing data are also unspecified. Three subjects were excluded after not returning to the clinic as required, but the record does not give group-specific details or explain the consequences of those exclusions.

The registry lists three outcome measures but posts no secondary results. It does not describe a multiplicity strategy or identify a prespecified statistical analysis plan. The primary endpoint is assessed at 90 days; longer-term outcome reporting is not included. Safety reporting lists counts for adverse-event categories, but the duration and methods of safety monitoring are not described.

The primary outcome results list 16 participants per group, while the safety record lists 17 at risk per group. The registry does not reconcile these counts with the stated enrollment of 51. These reporting gaps limit assessment of precision, risk of bias, and the relationship between the posted summaries and the original trial plan. They do not, on their own, establish that the trial procedures were inadequate; they define what cannot be evaluated from the registry record.

15. Related Tutorials

16. Related Statistical Calculators

17. Sources

• ClinicalTrials.gov: Effects of AMP Application After Non-surgical Periodontal Therapy on Treatment of Periodontitis — NCT05530252.
• Registry record last updated 2024-04-30; status last verified 2024-04.
• Results first posted 2024-04-30.
• 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

NCT05530252 is a completed, randomized, single-masked, parallel-group Phase 4 trial sponsored by Beijing Stomatological Hospital, Capital Medical University. It enrolled 51 participants and compared SRP with subgingival antimicrobial peptide gel, SRP with minocycline hydrochloride ointment, and SRP alone in Stage III and Grade B periodontitis.

The primary endpoint was change from baseline in periodontal probing depth at 90 days, measured in millimeters. The registry reports group means and lists 16 participants per group in the primary outcome analysis. It notes that three subjects did not return to the clinic as required and were excluded from final analysis. No between-group statistical analysis or secondary outcome results are posted. Safety counts list 0 affected participants and 0 deaths in each group, with 17 at risk per group for the reported categories.