To Measure Pain Perception Following De-Epithelized Free Gingival Graft Harvesting: Complete Statistical Analysis

1. Trial at a Glance

This page covers the registry results for To Measure Pain Perception Following De-Epithelized Free Gingival Graft Harvesting (NCT03895476), a randomized na study. The primary outcome is Pain Assessment (0=No Pain to 10=Worst).

2. Clinical Question

3. Trial Design

The registry describes a completed, randomized, parallel-group clinical trial with no masking. The stated enrollment was 72, distributed across four arms with 18 participants in each. The sponsor was the University of Alabama at Birmingham. The listed start date was 2020-06-08, and the primary completion date was 2021-07-30.

Participants were assigned to one of four palatal wound-coverage approaches after free gingival graft harvesting: collagen plug with sutures, PRF, CPC, or a palatal stent. The collagen-plug-with-sutures arm was the reference for the reported pairwise comparisons. The registry record does not report how randomization was generated or concealed, or further operational details about the assignment process.

The primary measure was pain on day 14, represented as a mean score and standard deviation in each arm. The outcome description says pain was assessed daily from days 1 to 14, but only the day-14 outcome is reported in the posted results. Three secondary measures are also reported for day 14: activity tolerance, amount of swelling, and need for painkiller. No additional outcome timing or detailed scale anchors for those secondary measures are reported in the registry record.

The trial is marked completed. The registry lists phase as NA and masking as none. It does not report a protocol-specific sample-size justification, a detailed statistical analysis plan, analysis-population definitions, or further information about participant flow. Those omissions limit what can be inferred about how the planned study was designed and how the reported summaries were selected.

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 Pain Assessment (0=No Pain to 10=Worst), measured over day 14.

The primary endpoint is pain assessment on day 14, reported as a mean score with a standard deviation. The measure is described as a visual analog scale ranging from 0, meaning no pain, to 10, meaning worst pain. The outcome description says pain was assessed daily from days 1 to 14, but the registry posts the day-14 result rather than the daily sequence.

A pain score offers a continuous summary of the reported experience across participants, rather than only classifying each participant as having or not having pain. Comparing arm means describes differences in average scores, while the standard deviations convey how dispersed participants’ scores were within each arm. These summaries do not show the individual score distribution or how many participants had scores at particular points on the scale.

The endpoint addresses pain after the palatal donor site was covered using one of the four methods. In general, a day-specific measure can support a comparison at that time point, but it does not by itself describe the course of pain over the full assessment period. The registry record does not report a minimally important difference or another threshold for deciding what size of score difference would be important to participants. Thus, the numerical contrast should be interpreted as a difference in reported average scores, not automatically as a difference of established clinical importance.

7. Results Posted in the Registry

• Platelet Rich Fibrin (PRF): mean 1.90 versus 4.20 on control; difference -2.30 (95% CI -3.77 to -0.83), standardized effect d = -1.02; z-test p = 0.002.
• Collagen Plug With Cyanoacrylate (CPC): mean 2.20 versus 4.20 on control; difference -2.00 (95% CI -3.60 to -0.40), standardized effect d = -0.82; z-test p = 0.014.
• Palatal Stent: mean 1.00 versus 4.20 on control; difference -3.20 (95% CI -4.48 to -1.92), standardized effect d = -1.63; z-test p = <0.001.

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.

Activity Tolerance

• 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:
  • Platelet Rich Fibrin (PRF): mean 1.50 versus 2.40 on control; difference -0.90 (95% CI -2.37 to 0.57), standardized effect d = -0.40; z-test p = 0.231.
  • Collagen Plug With Cyanoacrylate (CPC): mean 1.80 versus 2.40 on control; difference -0.60 (95% CI -2.17 to 0.97), standardized effect d = -0.25; z-test p = 0.453.
• Interpretation:
  • The 95% confidence interval includes no difference, so these data do not show a statistically significant difference between Platelet Rich Fibrin (PRF) and the control. The interval gives the range of effects that remain compatible with the data.
  • The 95% confidence interval includes no difference, so these data do not show a statistically significant difference between Collagen Plug With Cyanoacrylate (CPC) and the control. The interval gives the range of effects that remain compatible with the data.

Amount of Swelling

• 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:
  • Platelet Rich Fibrin (PRF): mean 1.30 versus 2.20 on control; difference -0.90 (95% CI -2.31 to 0.51), standardized effect d = -0.42; z-test p = 0.212.
  • Collagen Plug With Cyanoacrylate (CPC): mean 1.40 versus 2.20 on control; difference -0.80 (95% CI -2.24 to 0.64), standardized effect d = -0.36; z-test p = 0.277.
• Interpretation:
  • The 95% confidence interval includes no difference, so these data do not show a statistically significant difference between Platelet Rich Fibrin (PRF) and the control. The interval gives the range of effects that remain compatible with the data.
  • The 95% confidence interval includes no difference, so these data do not show a statistically significant difference between Collagen Plug With Cyanoacrylate (CPC) and the control. The interval gives the range of effects that remain compatible with the data.

The Need for Painkiller

• 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:
  • Platelet Rich Fibrin (PRF): mean 2.00 versus 2.10 on control; difference -0.10 (95% CI -1.77 to 1.57), standardized effect d = -0.04; z-test p = 0.906.
  • Collagen Plug With Cyanoacrylate (CPC): mean 2.20 versus 2.10 on control; difference 0.10 (95% CI -1.63 to 1.83), standardized effect d = 0.04; z-test p = 0.910.
• Interpretation:
  • The 95% confidence interval includes no difference, so these data do not show a statistically significant difference between Platelet Rich Fibrin (PRF) and the control. The interval gives the range of effects that remain compatible with the data.
  • The 95% confidence interval includes no difference, so these data do not show a statistically significant difference between Collagen Plug With Cyanoacrylate (CPC) and the control. The interval gives the range of effects that remain compatible with the data.

The three secondary measures concern activity tolerance, swelling, and need for painkiller, each reported for day 14. Taken together, the posted arm means suggest a broadly similar directional pattern for activity tolerance and swelling to the primary pain comparison: several coverage arms have lower scores than collagen plug with sutures. The comparisons do not show a similarly clear separation for painkiller need. The individual secondary estimates and intervals are available in the statistical results, but the registry record reports no formal secondary analyses.

These outcomes are related to the postoperative experience but measure different aspects of it. Activity tolerance, swelling, and painkiller need cannot be treated as interchangeable with the pain score. Their scales are described as scores, but further anchors and interpretation details are not reported in the registry record. In particular, the meaning of a score difference for these secondary measures cannot be evaluated against a stated clinical threshold.

The secondary results provide context for the primary endpoint rather than independent confirmation of it. Their comparisons are unadjusted, and no multiplicity strategy is reported. When several outcomes and pairwise contrasts are considered, chance alone can produce apparently notable results among the collection. For that reason, unadjusted secondary findings carry less weight than a prespecified primary comparison and should be considered exploratory unless the analysis plan says otherwise; the plan is not reported in the registry record.

Overall, the day-14 secondary summaries do not overturn the primary result, but neither do they establish a consistent or definitive effect across all dimensions of recovery. They are limited to the reported time point, and no daily trends or other follow-up summaries are posted. Their best use is to describe the broader outcome pattern while recognizing the small arm sizes and lack of reported inferential analyses for these outcomes.

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

• Activity Tolerance
• Amount of Swelling
• The Need for Painkiller

9. Statistical Interpretation

10. Statistical Methods Explained

The primary outcome is continuous: it is a score on a bounded visual analog scale, summarized by an arm mean and standard deviation. The registry identifies the mean as the measure of central tendency and the standard deviation as the measure of spread. Each reported arm includes 18 participants. The mean describes the average score in that group; the standard deviation describes how widely scores vary around that average. Neither summary shows the full distribution, possible skew, or the number of observations at any particular score.

What does a mean difference represent?

The posted pairwise comparisons use collagen plug with sutures as the reference. A mean difference is the compared arm’s mean minus the reference arm’s mean. A negative estimate therefore corresponds to a lower average score in the compared arm. For example, the PRF comparison is reported as -2.3, the CPC comparison as -2.0, and the palatal-stent comparison as -3.2. These differences are in points on the pain scale, not percentages or ratios.

The reported recalculations are unadjusted comparisons based on the arm summary statistics. They are not described as adjusted for participant characteristics or other variables. The registry record lists no reported analyses, and a protocol-specific statistical model or analysis plan is not reported in the registry record. The displayed pairwise results should therefore be understood as summary-based comparisons rather than as evidence of a more elaborate model.

How should p-values be read?

A p-value describes how compatible the observed data are with a specified null model, assuming that model and the calculation’s assumptions are appropriate. Smaller values indicate that results like the observed contrast would be less common under that null model. A p-value is not the probability that the null hypothesis is true, and it does not measure the size or importance of a difference. The comparisons report unadjusted p-values of 0.002 for PRF, 0.014 for CPC, and <0.001 for the palatal stent. Because multiple comparisons and outcomes are present, these individual values do not account for the full set of statistical questions.

What does a confidence interval add?

A confidence interval gives a range of estimates compatible with the data and the method used to calculate it. The primary comparisons’ intervals all lie below zero, which is consistent with lower mean pain scores in the compared arms than in the reference arm. Their widths also show that the point estimates should not be treated as exact. In general, confidence intervals depend on sampling variability and the statistical assumptions used; they do not account automatically for unreported sources of bias, outcome selection, or multiplicity.

Why does standard deviation matter?

In general, standard deviation helps describe participant-to-participant variability within an arm. Two arms can have different means while also having substantial variation in individual scores. The reported standard deviations for pain are 2.4 for collagen plug with sutures, 2.1 for PRF, 2.5 for CPC, and 1.4 for the palatal stent. These values provide context for the means, but do not reveal whether scores are symmetric, concentrated at particular scale values, or affected by outliers.

In general, a small sample can make estimates imprecise and can leave distributional features difficult to assess. The registry record does not report individual participant data, diagnostic checks, or the exact analysis procedure used for the sponsor’s primary analysis. The recalculated comparisons are therefore useful for interpreting the posted summaries, but cannot establish that all assumptions were satisfied.

What is not described?

The registry record does not report the trial’s original sample-size justification, prespecified analysis populations, missing-data procedures, handling of repeated daily pain assessments, or a multiplicity strategy. It also does not report whether interim analyses were planned or conducted. These details matter because analysis choices can affect the interpretation of estimates and uncertainty. Their absence from the registry record does not show that no such procedures existed; it means they cannot be assessed from the posted information.

The trial is randomized, which is relevant to how treatment groups are formed, but the record does not give enough information to evaluate the randomization process in detail. Masking is listed as none. In general, lack of masking can affect subjective outcomes through expectations or reporting, though the registry record does not establish that such effects occurred in this trial. The pain scale depends on participant-reported experience, making that context worth considering without assuming a particular direction of bias.

11. Confidence Intervals and Precision

The mean-difference confidence intervals describe uncertainty around the three day-14 comparisons with collagen plug with sutures. For PRF, the estimate is -2.3, with a 95% interval from -3.773 to -0.827. For CPC, the estimate is -2.0, with an interval from -3.601 to -0.399. For the palatal stent, the estimate is -3.2, with an interval from -4.484 to -1.916. All three intervals fall below zero, while their nonzero widths show that the exact size of each difference remains uncertain.

In general, a confidence interval is a way to express the range of effect estimates reasonably compatible with the data under the calculation method. It is not a range containing a fixed proportion of individual participants’ scores, and it is not a guarantee that the true effect lies within that particular interval. The intervals also do not include uncertainty from every possible design or analysis issue. For example, they do not by themselves address the consequences of unreported missing-data handling or multiplicity procedures.

The group sizes are 18 per arm, and the reported standard deviations indicate participant variability in pain scores. The estimated differences should therefore be read together with their intervals rather than as exact quantities. Although the intervals do not cross zero, that fact does not establish clinical importance. The registry record does not report a threshold for a meaningful difference on the scale, so the confidence intervals cannot be judged against such a threshold from the posted information.

The intervals accompany recalculated unadjusted comparisons from the posted summary statistics. The record indicates no discrepancy between those recalculations and the registry results. No sponsor-reported analysis is listed in the registry record, so the recalculated estimates should be treated as a statistical reading of the posted summaries, not as a replacement for an unpublished analysis.

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 sample-size figures are planning illustrations based on the observed effect, not the trial’s original design justification. For these continuous-outcome comparisons, the figures are participants per arm, not total events. The stated assumptions are a two-sided significance level of 0.05, equal allocation between the two arms, and a normal approximation; the effect to detect is the stated fraction of the observed effect. The trial’s own original sample-size assumptions and justification are not reported in the registry record.

The 80% power column gives the estimated participants per arm for a future study to have an 80% chance of detecting the specified effect under the listed assumptions, if that effect and the calculation assumptions are appropriate. The 90% power column gives the corresponding planning count for a 90% chance. These are prospective planning quantities, not a description of what happened in this completed trial. This is not observed power.

Rows planning for 100%, 75%, and 50% of the observed effect show how the assumed effect size changes the required group size. Smaller effects need more participants because they are harder to distinguish from sampling variation. For example, the PRF comparison’s planning figures rise from 16 participants per arm for 80% power when planning for 100% of the observed effect, to 27 for 75%, and 61 for 50%. The figures are illustrations, not recommendations, and depend on the assumptions stated with them.

The figures use the effect observed in this trial as their starting point. Such an estimate can be uncertain, particularly with 18 participants in each arm, so using it directly for a future design may not represent the effect that future research should target. The registry record does not report a separate original target effect or the assumptions used to choose the trial’s enrollment.

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, Δ is the difference in means to detect and σ is the common standard deviation.

Worked calculation for this trial

1. Observed difference Δ = -2.300; pooled standard deviation σ = 2.255.
2. n = 2 × (1.96 + 0.842)² × 2.255² / -2.300² = 15.1, rounded up to 16 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
delta <- -2.3                      # observed difference in means
sigma <- 2.25499445675594                     # pooled standard deviation
n_per_arm <- function(power, frac = 1) {
  ceiling(round(2 * (z_a + qnorm(power))^2 * sigma^2 / (delta * frac)^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 (t-based, so very slightly larger)
cat("power.t.test:", round(power.t.test(delta = delta, sd = sigma, power = 0.80)$n, 1), "\n")

# Simulation: exact two-sample t-test using simulated means and variances
set.seed(3895476)
n    <- n_per_arm(0.80)
reps <- 20000
m_diff <- rnorm(reps, delta, sigma * sqrt(2 / n))             # difference in sample means
s2     <- sigma^2 * rchisq(reps, 2 * (n - 1)) / (2 * (n - 1))   # pooled sample variance
tstat  <- m_diff / sqrt(s2 * 2 / n)
cat(sprintf("Simulated power at n = %s per arm: %.3f (%d replicates)\n", format(n, big.mark = ","), mean(abs(tstat) > qt(0.975, 2 * (n - 1))), reps))

Output from running the code

100% of observed effect: n per arm = 16 (80% power), 21 (90% power)
 75% of observed effect: n per arm = 27 (80% power), 36 (90% power)
 50% of observed effect: n per arm = 61 (80% power), 81 (90% power)
power.t.test: 16.1 
Simulated power at n = 16 per arm: 0.798 (20000 replicates)

The simulation draws many sets of group means and variances at the planned sample size and counts how often the two-sample t-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

The registry lists a primary outcome and three secondary outcomes, with comparisons of three coverage methods against the collagen-plug-with-sutures reference for the primary outcome. It does not report how the number of statistical tests was handled. No multiplicity adjustment or hierarchy for interpreting the outcomes is reported in the registry record. The posted primary comparison p-values are unadjusted, and no reported analyses are listed for the secondary outcomes.

Multiplicity matters because the chance of at least one apparently unusual result can increase when many comparisons are examined. In general, methods such as adjusting the significance threshold or specifying a testing order can address particular multiplicity concerns, but the registry record does not identify a method used in this trial. It is therefore appropriate to treat the individual p-values as unadjusted evidence for their respective comparisons, rather than as accounting for all outcomes and contrasts together.

The pain outcome description says assessments were made daily from days 1 to 14, while the posted primary result is for day 14. The registry record does not report whether the repeated assessments were analyzed jointly, whether day 14 was prespecified as the only reported time point, or how any other time-point results were handled. This missing information limits assessment of selection across time points.

Missing-data procedures and analysis populations are not reported in the registry record. Although 18 participants are listed in each arm for the posted summaries, that does not by itself establish whether all randomized participants contributed data to every outcome or how incomplete observations were handled. The record also does not report an intention-to-treat definition, exclusions after randomization, imputation methods, or sensitivity analyses. These omissions prevent evaluation of whether missingness or analysis-set choices could affect the estimates.

The record does not report interim analyses or a detailed statistical analysis plan. This should be read as a lack of information in the registry record, not evidence that such planning or procedures did not occur. Without those details, the degree to which outcomes, time points, and analytic choices were prespecified cannot be assessed from the posted information.

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 18 participants at risk for serious adverse events in each arm and zero serious adverse events in every arm. It also reports 18 at risk for other adverse events in each arm and zero other adverse events in every arm. Deaths are reported as zero in each arm. No serious adverse event terms are listed.

These figures describe the events recorded in the registry for the stated groups. Zero recorded events does not establish that an approach has no risks, and the small group sizes limit how much can be learned about uncommon events. The record does not report additional details about the adverse-event observation period, event collection procedures, severity definitions, or whether there were withdrawals related to adverse events.

The safety summaries should be read alongside the trial’s size and the limited detail reported. They describe the posted event counts, not a comprehensive comparison of safety across the four methods.

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

The posted primary results show lower average day-14 pain scores in the PRF, CPC, and palatal-stent arms than in the collagen-plug-with-sutures arm. The recalculated mean differences and their confidence intervals all lie below zero. This is a description of the reported group summaries and unadjusted comparisons for the trial’s stated primary outcome.

The result does not show that one method is definitively best across all outcomes or time points. The registry reports day-14 values, not the full daily pain trajectory, despite describing daily assessments from days 1 to 14. It also does not provide a reported analysis directly comparing the three alternative methods with one another. Their ranking by observed mean does not establish that their effects differ from each other.

The result does not establish whether the score differences are clinically important. The record does not report a minimally important difference or another threshold for interpreting the size of a pain-score change. Nor do the p-values quantify the probability that a method is effective or that the observed difference is due to chance. They are unadjusted measures of compatibility with a null model and should be interpreted together with the estimates, confidence intervals, and multiplicity limitations.

Randomized allocation is part of the trial design, but the registry gives no detailed account of the randomization process, and the study is listed as unmasked. The posted summary statistics cannot rule out bias, assess the effects of missing data, or demonstrate that the estimates will apply to populations or settings beyond those represented in the trial. Eligibility details and participant characteristics are not reported in the registry record.

The results therefore offer a statistical description of the day-14 outcome in this completed trial. They do not provide medical advice, guarantee an individual outcome, or settle questions that require fuller information on design, analysis, longer-term outcomes, and clinical importance.

17. Why This Trial Matters Statistically

This trial illustrates why the estimated difference, its precision, and the analysis context should be considered together. The arm means give a direct description of day-14 pain scores, while mean differences express the comparisons against a shared reference. Confidence intervals add information about uncertainty that a ranking of means alone cannot provide.

It also shows how a statistically distinct comparison is not automatically a clinically important one. The reported primary intervals lie below zero, but the registry record does not define a meaningful score difference. Statistical evidence about the direction of a contrast and evidence about its practical importance are different questions.

The study’s four arms make multiplicity relevant. Several methods are compared with one reference, and additional outcomes are reported. Because no multiplicity approach or analysis plan is described, interpretation should not treat each unadjusted result as if it were the only test considered. This is especially important for secondary outcomes, where no formal analyses are reported.

Finally, the example highlights the distinction between a study’s reported enrollment and a sample-size justification. Planning illustrations can show how assumptions about effect size and power influence future group sizes, but they do not reveal why the trial enrolled its participants. The original justification is not reported in the registry record. Understanding that distinction helps prevent planning calculations from being mistaken for evidence about the completed trial’s power or design rationale.

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 reported outcome groups are small, with 18 participants per arm. This limits precision and makes the estimates potentially sensitive to individual scores. The confidence intervals convey sampling uncertainty for the recalculated comparisons, but do not resolve the limitations of small groups or establish clinical importance.

The study is listed as unmasked, and the primary outcome is a participant-reported pain score. In general, lack of masking can affect subjective reporting, although the registry record does not establish that it did so. The record does not report further details about how outcome assessments were administered or whether assessors were masked.

The primary outcome description states that pain was assessed daily from days 1 to 14, but only day-14 results are posted. The secondary outcomes are also reported for day 14. The registry record does not report the full repeated-measures pattern, longer follow-up, or a clinical-importance threshold. Secondary scale anchors beyond describing scores are not reported.

Further limitations arise from missing methodological detail. The original sample-size justification, analysis populations, missing-data procedures, detailed statistical plan, handling of multiple comparisons, and interim-analysis information are not reported in the registry record. Participant characteristics and eligibility criteria are also not reported. These gaps make it difficult to evaluate applicability, prespecification, and the possible effect of incomplete outcome data.

Finally, the available comparisons use collagen plug with sutures as the reference and do not provide reported pairwise analyses among the other three arms. The observed means alone cannot establish statistically reliable differences among those methods. The posted safety counts also offer limited information about uncommon events in groups of this size.

19. Related Tutorials

20. Related Statistical Calculators

21. Sources

• ClinicalTrials.gov: To Measure Pain Perception Following De-Epithelized Free Gingival Graft Harvesting — NCT03895476.
• Registry record last updated 2024-08-23; status last verified 2024-08.
• Results first posted 2024-08-23.
• 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

NCT03895476 is a completed randomized, parallel-group trial of four methods for covering the palatal donor site after free gingival graft harvesting. The registry lists no masking, an enrollment of 72, and the University of Alabama at Birmingham as sponsor. The listed start date was 2020-06-08, and the primary completion date was 2021-07-30.

The primary outcome was day-14 pain on a visual analog scale from 0, no pain, to 10, worst pain. Day-14 means were lower in the PRF, CPC, and palatal-stent arms than in the collagen-plug-with-sutures reference arm. Recalculated unadjusted comparisons showed mean differences below zero, with confidence intervals that also fell below zero.

Three day-14 secondary outcomes and adverse-event counts are posted. The registry record does not report a detailed statistical analysis plan, sample-size justification, multiplicity strategy, analysis populations, or missing-data procedures. Interpretation is consequently limited to the posted summaries and the stated uncertainty around the recalculated comparisons.