Role of Propolis Paste in Preventing Pain After Root Canal Treatment.: Complete Statistical Analysis

1. Trial at a Glance

This page covers the registry results for Role of Propolis Paste in Preventing Pain After Root Canal Treatment. (NCT03723980), a randomized phase 3 study. The primary outcome is Pain Intensity Measure: Visual Analogue Pain Scale.

2. Clinical Question

In statistical terms, this is a comparison of a continuous patient-reported outcome between randomized groups across multiple follow-up times. The registry also names acute increase in pain score and differences in pain score between time intervals as secondary outcomes. Those descriptions indicate additional questions about worsening and change over time, but the definitions and numerical results for those outcomes are not reported in the registry record. The clinical question is therefore identifiable, while the magnitude and precision of the observed pain differences cannot be described from the outcome information in the registry record.

3. Trial Design

The registry describes a phase 3, randomized, double-blind, parallel-group clinical trial. It is marked completed, with enrollment of 80. The comparison was between propolis and calcium hydroxide, each used as an intracanal medicament after root canal preparation in necrotic (infected) teeth. The registry summary says half of participants would receive calcium hydroxide and half propolis. The adverse-event record lists 40 participants at risk in each group.

Random allocation is intended, in general, to make treatment groups comparable on average at the start of a study. A parallel-group design means that participants are assigned to one treatment group rather than crossing between treatments. Double masking generally means that two categories of people involved in the trial are kept unaware of treatment assignment, but the identities of the people masked and the procedures used to preserve masking are not reported in the registry record. The method used to generate the random sequence and the method used to conceal allocation are also not reported in the registry record.

The primary outcome was self-recorded pain intensity at 4 hours, 12 hours, day 2, day 3 and day 4 after root canal preparation and intracanal medicament insertion at the first visit. The registry also identifies two secondary outcome topics: acute increase in pain score and differences between pain-score time intervals. Numerical results for these outcomes, and details about their analyses, are not reported in the registry record.

The registry record reports that 12 patients did not return for follow-up and could not be contacted. It states that 7 were in the control group and 5 in the experimental group, and that 33 control-group and 35 experimental-group patients could be analyzed. Reasons for non-return beyond the lack of follow-up and contact, and the handling of missing outcome values, 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

Analysis population for the primary outcome, as defined in the registry: Out of 80 patients, 12 did not return for follow-up; and no contact could be established with them. Out of these 12 patients, 7 belong to control group and 5 belong to experimental group. Hence, 33 patients in control group and 35 patients in experimental group could be analyzed

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 Intensity Measure: Visual Analogue Pain Scale, measured over 4 hours, 12 hours, day 2, day 3 and day 4.

The primary endpoint is pain intensity recorded by patients on a Visual Analogue Scale from 0 to 100. Patients recorded pain at 4 hours, 12 hours, day 2, day 3 and day 4 after root canal preparation and placement of the intracanal medicament at the first visit. The registry describes the outcome as a mean, with standard deviation, at these timepoints.

The record links ranges of scores to reported pain severity and analgesic use: scores from 0 to 24 correspond to no or mild pain without a need for analgesic; 25 to 49 to moderate pain and need for an over-the-counter analgesic; 50 to 74 to severe pain and use of a codeine-containing medicine; and 75 to 100 to extreme pain not relieved by medicine. These are the registry’s stated interpretation bands, not separate outcome measures. The registry explicitly says that a lower pain score is a better outcome than a higher pain score.

Patient-recorded pain scores are used because pain is an experience reported by the patient, and repeated records can describe its course after treatment. A mean gives a group-level summary, while a standard deviation describes the spread of individual scores around that mean. As a general statistical point, these summaries do not show every person’s experience, and a group mean does not establish how many patients fell within any particular severity band. Numerical means and standard deviations by group and timepoint are not reported in the registry record, so the size and precision of the observed differences cannot be assessed from the available outcome information.

7. Why No Re-analysis Is Shown

8. Statistical Interpretation

9. Statistical Methods Explained

The registry describes the primary outcome as a continuous measure summarized by a mean and standard deviation. It identifies five follow-up times: 4 hours, 12 hours, day 2, day 3 and day 4. Numerical results for these measurements are not reported in the registry record. The methods below explain how such summaries and comparisons are generally interpreted; they do not identify analyses that the trial necessarily performed.

What does a mean describe?

In general, a mean combines participants’ observed values into a group-level average. For a pain score, it can indicate the central level of recorded scores in a treatment group at a given time. It does not describe every participant’s score, and the same mean can arise from different patterns of individual responses. The standard deviation describes the amount of dispersion of the observed scores around the mean. It is not the uncertainty in the mean itself; a standard error or confidence interval is commonly used to describe uncertainty in an estimated mean.

The scale runs from 0 to 100, and the registry states that lower scores indicate a better outcome. It also gives score ranges corresponding to pain severity and analgesic use. Those bands can help interpret the recorded scale, but a mean alone does not show how many participants had no or mild, moderate, severe or extreme pain. A distribution of individual scores or counts within categories would be needed to describe that aspect. Such group-level category results are not reported in the registry record.

Why are repeated measurements important?

Repeated pain scores can describe how reported pain changes after treatment. In general, scores from one participant at different times are related rather than independent. An analysis that compares groups separately at each timepoint and an analysis that models the whole course over time answer different questions and may use the information differently. A model for repeated observations can account for within-participant association, but its specification and use are not reported in the registry record.

For example, a group contrast at a particular follow-up time asks whether average scores differ at that time. A treatment-by-time comparison asks whether the pattern of change over the follow-up period differs between groups. These are general descriptions of possible estimands, not claims about the trial’s actual analyses. The registry record does not identify a prespecified timepoint as the sole primary comparison or report an overall treatment effect across time.

How should uncertainty be read?

In general, a confidence interval gives a range of values compatible with an estimate under the analysis assumptions and conveys its statistical precision. A narrow interval indicates greater precision than a broad interval, while the location of the interval helps readers judge which effect sizes remain compatible with the data. A p-value is a measure calculated under a specified hypothesis and model; it is not the probability that a treatment works, and it does not communicate effect size on its own. The registry record does not report confidence intervals or p-values for the primary pain outcome, so neither statistical precision nor evidence relative to a null hypothesis can be assessed from it.

What can be said about planning calculations?

A sample-size planning illustration is described as using the observed effect, a two-sided significance level of 0.05, equal allocation between arms, and a normal approximation. It is explicitly a planning illustration rather than the trial’s own design calculation. The registry record does not report the trial’s sample-size justification. A calculation based on an observed effect should not be read as observed power: it is a planning exercise that depends on the chosen effect and assumptions, not a measure of how likely the completed trial was to detect an effect.

In general, planning for a smaller effect requires more information than planning for a larger effect, all else held constant. Such illustrations are conditional on assumptions, including the effect size and allocation pattern. The particular effect fractions and numerical participant requirements are not reported in the registry record, so no planning requirement can be stated. The illustrations cannot substitute for the missing outcome estimates and their uncertainty.

Why can outcome variability matter?

Standard deviations help characterize variability in continuous outcomes. If scores vary substantially among participants, a group mean can be estimated less precisely than when observations are more tightly clustered, all else equal. Some continuous outcomes may also have skewed distributions or many scores near a scale boundary. General statistical methods may need to account for such patterns; the observed distribution of pain scores and any diagnostic checks are not reported in the registry record. No claim about the distribution or adequacy of a particular model can therefore be made.

The record lists 25 analyses and 5 outcome measures, but does not provide the statistical model specifications, analysis code, or numerical primary-outcome results. The analysis population is described as patients who could be analyzed after those who did not return were lost to follow-up. The method for handling missing outcome values is not reported. These omissions limit assessment of how the reported design was translated into statistical estimates.

10. Multiplicity, Missing Data and Analysis Populations

The primary pain outcome has several follow-up times, and the registry also lists acute increase in pain score and differences of pain score between time intervals as secondary outcomes. The record identifies 5 outcome measures and 25 analyses. Testing or estimating multiple outcomes and timepoints raises multiplicity questions: when many comparisons are made, the chance of at least one result appearing notable can increase. General approaches include defining a hierarchy of outcomes, adjusting inferential thresholds, or clearly treating secondary analyses as exploratory. Which approach, if any, was used is not reported in the registry record.

The record does not reduce the multiple primary-outcome timepoints to one comparison, and the numerical estimates for those timepoints are not reported. It also does not report a prespecified testing sequence, multiplicity adjustment, or distinction between confirmatory and exploratory analyses. Thus, the intended interpretation of a collection of possible comparisons cannot be reconstructed from the record.

Missing data are relevant because 12 patients did not return for follow-up and could not be contacted. The record states that 7 belonged to the control group and 5 to the experimental group; it reports that 33 control-group and 35 experimental-group patients could be analyzed. These are the stated analysis counts. The reasons for non-return, the amount of missingness at each pain-assessment time, and the approach to missing measurements are not reported in the registry record.

In general, an analysis restricted to observed cases estimates the comparison among those with available measurements, while an analysis using all randomized participants requires assumptions or methods for unobserved outcomes. Missingness can be especially consequential if the chance of a missed measurement is related to pain or treatment experience. The record does not report enough information to judge that possibility, the target analysis population, or the sensitivity of findings to alternative missing-data assumptions.

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.

Most frequent non-serious adverse event terms

The registry reports no serious adverse events in either group and no deaths in either group. For other, non-serious events, it reports 4 affected in the calcium hydroxide group and 6 affected in the propolis group, with 40 at risk in each group. These are the event figures recorded for the trial; the types of other events and their relationship to treatment are not reported in the registry record.

In general, an adverse-event count describes what was recorded during the study and is not, by itself, proof that a treatment caused an event. Interpreting a safety comparison also requires consistent definitions, collection methods, follow-up, and information about severity and attribution. Those details are not reported in the registry record. The registry’s report of no serious events should therefore be read as a description of the recorded trial experience, not as evidence that serious events cannot occur.

The record’s at-risk figures provide the group counts used for these safety entries. They should not be conflated with the pain analysis population, which the registry describes separately after loss to follow-up. The available safety entries do not provide event timing, recurrent-event details, or a comparative statistical analysis. They are descriptive counts and do not establish a statistically reliable safety difference.

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

The registry record establishes that a randomized, double-blind, parallel-group trial compared propolis paste with calcium hydroxide as intracanal medicaments after root canal treatment in necrotic teeth. It identifies patient-recorded pain intensity as the primary outcome and specifies assessment at 4 hours, 12 hours, day 2, day 3 and day 4. It also describes the scale and states that lower scores are better. These details define what the study set out to measure.

The record does not report numerical pain scores by treatment group or timepoint, between-group estimates, confidence intervals, or p-values. As a result, it does not support a conclusion about the direction, magnitude, or precision of the comparative pain results. The missing numerical results also prevent assessment of whether any difference was concentrated at a particular time or persisted over the recorded follow-up period.

Even when numerical differences are available, statistical interpretation distinguishes an estimated effect from its uncertainty and from its clinical importance. A small p-value does not establish that a difference matters to patients, and a nonsignificant result does not establish equivalence. Equivalence or non-inferiority questions require an appropriate design and a prespecified margin; those details are not reported in the registry record. No such conclusion can be drawn from the design description alone.

The follow-up information is also relevant. The registry says 12 patients did not return and could not be contacted, and reports the numbers analyzed in each group. Without a reported missing-data approach or sensitivity analyses, the effect of missing outcomes on any comparison cannot be judged. The safety entries report no serious adverse events or deaths and record other events in both groups, but event descriptions and attribution are absent. These data provide a limited account of what was recorded, not a complete characterization of comparative safety.

Thus, the record supports a description of the study question, structure, endpoint, analysis counts, and adverse-event entries. It does not support claims that either medicament produced less pain, that the treatments were equivalent, or that one was safer. Such conclusions would require outcome estimates and adequate details about analysis and follow-up.

13. Why This Trial Matters Statistically

This trial is statistically instructive because its primary outcome is a patient-reported continuous measure collected repeatedly after treatment. Repeated scores can describe both the level of pain and its time course, but they create a choice about the target comparison: a specific follow-up time, a change from an earlier score, or an overall pattern across time. Those choices should be defined clearly because they answer distinct questions. The registry identifies the measurement times but does not report a single summary comparison or the statistical model used.

The score also has practical interpretation bands tied to pain severity and analgesic use. A mean is useful for comparing group-level averages, but it can obscure variation and does not reveal how many participants experienced pain in each band. Reading a continuous summary alongside distributions or category counts can provide a fuller description, though those results are not reported in the registry record.

Missing follow-up is another important statistical feature. The registry reports patients who did not return and gives the group counts that could be analyzed. Any comparison based on available scores depends, in general, on how missing observations relate to the unobserved scores. Without reasons for non-return, time-specific missingness, and an analysis strategy, it is difficult to assess the robustness of results even if estimates were available.

Finally, the record lists multiple outcome measures and analyses. This makes the distinction between a prespecified primary comparison and exploratory results important. A clear analysis plan helps readers understand how multiplicity was addressed and which findings carry confirmatory weight. The plan and numerical outcome results are not reported in the registry record. These gaps make the trial a useful example of why design labels alone are not enough for statistical interpretation: the estimand, analysis, uncertainty, missing-data handling, and outcome reporting all matter.

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 main limitation for interpreting this trial from the registry record is the absence of numerical primary-outcome results. No group means, standard deviations, treatment contrasts, confidence intervals, or p-values for pain intensity are reported. This prevents assessment of the observed difference and its statistical precision.

The primary outcome is measured at several follow-up times, but the record does not identify a single primary timepoint or describe how repeated measurements were analyzed. It also names secondary pain outcomes without reporting their operational definitions or results. The analysis plan, including model assumptions and any multiplicity procedures, is not reported in the registry record.

The follow-up description notes that 12 patients did not return and could not be contacted. The record gives the group distribution of those patients and states how many in each group could be analyzed, but it does not report reasons for non-return, time-specific missingness, or methods for addressing missing scores. It is therefore not possible to determine how selection of the analyzed participants may have affected the pain comparison.

The registry describes the trial as randomized and double-blind but does not report the random-sequence method, allocation concealment, or who was masked. It also does not report the trial’s sample-size justification. The planning illustration described in the record is based on the observed effect and is not the trial’s design calculation. Safety information is limited to event counts; the other-event terms, attribution, and collection details are not reported. These limitations restrict evaluation of outcome reliability, analysis choices, and safety interpretation.

15. Related Tutorials

16. Related Statistical Calculators

17. Sources

• ClinicalTrials.gov: Role of Propolis Paste in Preventing Pain After Root Canal Treatment. — NCT03723980.
• Registry record last updated 2019-06-06; status last verified 2019-03.
• Results first posted 2019-06-06.
• Data retrieved from ClinicalTrials.gov on 2026-11-09.
• Group sizes, means, event counts and sponsor-reported p-values are reproduced as posted. Effect estimates, confidence intervals and p-values not attributed to the sponsor are independently calculated from the posted summary statistics.

18. Record Summary

The registry record describes a completed phase 3 randomized, double-blind, parallel-group trial comparing propolis paste with calcium hydroxide as an intracanal medicament after root canal treatment for necrotic teeth. Enrollment was 80. The primary outcome was patient-recorded pain intensity on a Visual Analogue Scale from 0 to 100, measured at 4 hours, 12 hours, day 2, day 3 and day 4.

The record states that 12 patients did not return for follow-up and could not be contacted; 7 were in the control group and 5 in the experimental group. It reports that 33 control-group and 35 experimental-group patients could be analyzed. Numerical primary pain results and the statistical analysis details are not reported in the registry record. The safety entries report no serious adverse events or deaths in either group and record other events for both groups.