Study to Evaluate the Effectiveness of Test Dentifrice in the Relief of Dentinal Hypersensitivity: Complete Statistical Analysis

1. Trial at a Glance

This page covers the registry results for Study to Evaluate the Effectiveness of Test Dentifrice in the Relief of Dentinal Hypersensitivity (NCT07317128), a randomized na study. The primary outcome is Adjusted Mean Change From Baseline in Schiff Sensitivity Score at Week 12 (Test Dentifrice Versus [vs] Negative Control Dentifrice).

2. Clinical Question

3. Trial Design

This completed study was randomized, single-masked, and used a parallel-group model. It enrolled 120 participants and evaluated dentifrices for dentin sensitivity. The registry lists three interventions: Test Dentifrice, Colgate Sensitive ProRelief, and Colgate Triple Protection. The arm descriptions use the labels Test Dentifrice, Comparator Dentifrice, and Negative Control Dentifrice. The registry record does not explicitly map the listed product names to the latter two arm labels, so their identities should not be inferred from the labels alone.

The study began on 2013-01-20, and primary completion was recorded as 2013-06-08. The stated purpose was to compare the clinical efficacy of test fluoride dentifrice with a standard fluoride dentifrice, measured by evaporative air sensitivity after 12 weeks of twice-daily brushing. The primary outcome is specifically a comparison of Test Dentifrice with Negative Control Dentifrice, rather than the standard-comparator contrast described in the brief summary. The registry also lists outcomes comparing the comparator and negative control, and test and comparator.

For all three arm descriptions, participants were instructed to apply a full ribbon of the assigned dentifrice to cover the toothbrush head and brush twice daily for one timed minute throughout the 12-week treatment period. The record identifies the primary efficacy population as randomized participants who received treatment at least once and had at least one post-baseline efficacy assessment. The endpoint results list 42 participants in the Test Dentifrice group and 38 in the Negative Control Dentifrice group.

The trial phase is recorded as not applicable. More detailed information about sequence generation, concealment, the identity of the masked party, and procedures for maintaining masking is not reported in the registry record. The original sample-size justification and detailed design assumptions are also 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.

Before assignment: A total of 120 participants were enrolled and randomized into three treatment groups: 42 participants to the Test Dentifrice group, 40 participants to the Comparator group and 38 participants to the Negative Control group. All 120 participants completed the study.

Overall Study

Analysis population for the primary outcome, as defined in the registry: The intent-to-treat (ITT) population included all participants who were randomised, administered the study treatment at least once during the study and provided at least one post-baseline assessment of efficacy.

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.

Population: Safety Population was defined as all participants who were randomised and administered at least one study treatment during the study.

6. Primary Endpoint

The registry lists the primary outcome as Adjusted Mean Change From Baseline in Schiff Sensitivity Score at Week 12 (Test Dentifrice Versus [vs] Negative Control Dentifrice), measured over Baseline and Week 12.

The primary endpoint was adjusted mean change from baseline in Schiff Sensitivity Score at Week 12, comparing Test Dentifrice with Negative Control Dentifrice. The score measured the response to a standardized air stimulus applied by an examiner to test teeth. A response was rated from 0 to 3: 0 indicated no response; 1 indicated a response without asking for the stimulus to stop; 2 indicated a response with a request to stop; and 3 indicated a painful response with a request to stop.

The outcome was calculated as the score at the indicated timepoint minus the baseline score. Because lower scores indicate improvement, a negative change means the score decreased from baseline. The group estimates are least-squares means, which are model-based adjusted means; the registry reports the group contrast as an adjusted mean difference from an ANCOVA analysis.

A standardized stimulus and defined rating scale give the outcome a consistent way to describe sensitivity responses over time. Change from baseline focuses the comparison on movement in the score rather than the Week 12 score alone. The endpoint is a continuous score, and its group contrast estimates the average adjusted difference in change between the two arms. The registry record does not report a threshold for a clinically important change, so statistical evidence about a group difference cannot by itself establish how important that difference is to participants.

7. Results Posted in the Registry

• Test Dentifrice: mean -1.19 versus -0.44 on control; difference -0.75 (95% CI -1.02 to -0.48), standardized effect d = -1.21; z-test p = <0.001.

8. Statistical Interpretation

9. Statistical Methods Explained

What does the mean change describe?

The outcome is a continuous score measured at baseline and Week 12. A change score expresses the later measurement relative to baseline: the Week 12 score minus the baseline score. Here, negative values indicate a reduction in Schiff Sensitivity Score, and the scale description says lower scores indicate improvement. The reported group means describe average change, not the response of every participant. Individual participants may have had changes different from their group's mean, but individual-level results are not reported in the registry record.

The Test Dentifrice estimate was -1.19 and the Negative Control Dentifrice estimate was -0.44. The reported adjusted contrast was -0.75. That contrast is expressed as Test Dentifrice relative to Negative Control Dentifrice; its negative direction corresponds to a larger average decrease for the test group on this change-score scale. It is a difference between group averages, not a percentage or a probability of improvement.

What does adjustment mean in the reported analysis?

The sponsor's reported method is ANCOVA, with the result expressed as an adjusted mean difference. In general, ANCOVA estimates a group contrast while accounting for specified model terms, which can include baseline outcome values or other covariates. The actual covariates and model specification are not reported in the registry record, so the adjustment cannot be described more specifically. The adjusted contrast should not be assumed to be identical in meaning or calculation to a direct subtraction of the two posted group means.

A separate recalculation can use the posted summary statistics to estimate a simple, unadjusted contrast and its uncertainty. It is useful as a check on the direction and broad scale of the reported result, but it does not reproduce the ANCOVA model. For that reason, the sponsor's reported ANCOVA analysis is the primary statistical result. The record does not indicate a discrepancy between the posted summaries and the reported analysis.

How should the p-value be read?

In general, a p-value describes how unusual data at least as incompatible with a specified null model would be if that model and the test assumptions held. The reported primary p-value is < 0.001. It is evidence against a zero adjusted difference under the stated analysis. It is not the probability that the null hypothesis is true, nor does it measure the size or clinical importance of the difference. Interpretation also depends on the model, data quality, and analysis plan; details beyond the named ANCOVA are not reported in the registry record.

What does the confidence interval add?

In general, a confidence interval describes a range of values reasonably compatible with the data and statistical model at a stated confidence level. The reported 95% confidence interval for the adjusted mean difference is -1.01 to -0.48. Its endpoints are both negative, indicating that the interval for this contrast is on the side favoring a greater mean decrease in the Test Dentifrice group according to the outcome's direction. The interval conveys uncertainty in the estimated difference, but it does not account for unreported sources of bias or establish clinical importance.

Why does over-dispersion matter?

Over-dispersion is a general concern for some count or binary outcomes when observed variability exceeds what a model assumes. The primary endpoint is a continuous score, and the registry identifies a standard error for its group estimates. The record does not report an over-dispersion analysis. Thus, over-dispersion is not a stated feature of the primary analysis; the relevant general lesson is that model assumptions should match the outcome and its variability, and the details needed to assess those assumptions are not reported in the registry record.

What can and cannot be reconstructed?

The registry supplies group estimates, participant counts, and standard errors, and the site presents simple recalculations based on those posted summaries. Such calculations are unadjusted and approximate; they cannot recover participant-level data, the exact ANCOVA specification, or any model diagnostics. The reported analysis uses an adjusted mean difference and its own confidence interval and p-value. Without details of the model terms, missing-data procedures, or diagnostics, readers cannot independently reproduce the sponsor's analysis from the summary statistics alone.

10. Confidence Intervals and Precision

The sponsor-reported adjusted mean difference was -0.75, with a 95% confidence interval from -1.01 to -0.48. The interval is entirely below zero, consistent with the negative estimated contrast. Given the score direction, this means the estimate and interval indicate a greater average decrease in Schiff Sensitivity Score in the Test Dentifrice group than in the Negative Control Dentifrice group under the reported analysis.

In general, a confidence interval communicates both the estimated direction and the uncertainty around the estimate. It is not a range containing every participant's result, and it is not a guarantee that the true effect lies within the endpoints. Its interpretation depends on the model and assumptions used to construct it. The registry names ANCOVA but does not report the full model specification, so the interval can be interpreted as the sponsor's reported model-based uncertainty rather than independently verified uncertainty.

The group estimates are accompanied by standard errors, and the number of participants listed for the primary comparison is 42 in the test group and 38 in the negative control group. A standard error describes uncertainty in an estimated mean, not the spread of individual participant scores. The registry does not report a standard deviation for the primary outcome or individual-level distributions. Consequently, the posted means and interval do not show how much participants' responses varied within each group.

Statistical precision is distinct from clinical relevance. The registry does not report a clinically important threshold for the score or for the between-group difference. The interval can therefore describe the estimated statistical range but cannot determine whether values in that range correspond to changes participants would consider meaningful. Nor does precision address possible bias, missing-data effects, or the consequences of conducting multiple analyses.

11. Planning a Similar Trial: Sample Size

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

The planning figures are participants per arm for the primary continuous-outcome comparison, not total events. They are illustrations calculated from the observed effect, not the original trial's design calculation. The listed assumptions are a two-sided significance level of 0.05, equal allocation between the two arms, and a normal approximation. The planning rows consider detecting 100% of the observed effect, 75% of the observed effect, or 50% of the observed effect.

For planning for 100% of the observed effect, the figures are 11 participants per arm for 80% power and 15 participants per arm for 90% power. For planning for 75% of the observed effect, they are 20 participants per arm for 80% power and 26 participants per arm for 90% power. For planning for 50% of the observed effect, they are 43 participants per arm for 80% power and 58 participants per arm for 90% power.

In general, power is the chance that a planned study will detect an effect of a specified size under its assumptions if that effect is present. The 80% and 90% columns describe different planning targets: the 90% target aims for a greater chance of detection than the 80% target and therefore requires more participants in these listed scenarios. The rows also illustrate that smaller effects need more participants to detect than larger effects, holding the listed assumptions fixed.

The original trial's sample-size justification and design assumptions are not reported in the registry record. These calculations use the observed effect and are planning illustrations, not observed power. Because the observed effect can be uncertain, the figures should not be read as evidence that the completed trial had a particular probability of success.

12. 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 = -0.750; pooled standard deviation σ = 0.620.
2. n = 2 × (1.96 + 0.842)² × 0.620² / -0.750² = 10.7, rounded up to 11 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 <- -0.75                      # observed difference in means
sigma <- 0.620237175478989                     # 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(7317128)
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 = 11 (80% power), 15 (90% power)
 75% of observed effect: n per arm = 20 (80% power), 26 (90% power)
 50% of observed effect: n per arm = 43 (80% power), 58 (90% power)
power.t.test: 11.8 
Simulated power at n = 11 per arm: 0.772 (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.

13. Analyses Reported by the Sponsor

The sponsor's posted primary analysis is an ANCOVA comparison of Test Dentifrice with Negative Control Dentifrice. It reports an adjusted mean difference of -0.75, a 95% confidence interval from -1.01 to -0.48, and p < 0.001. The adjusted estimate is the principal result for interpreting the registry's primary endpoint.

The simple recalculation uses posted group summary statistics to obtain an unadjusted comparison. It is not the same as the ANCOVA: adjustment terms and participant-level information needed to reconstruct the sponsor's model are not reported in the registry record. The recalculation is therefore best treated as a summary-statistic check, not as a competing model-based result. The record does not flag a discrepancy between the posted summaries and the sponsor analysis, and the sponsor's own analysis takes precedence if a discrepancy is present.

The recalculated p-value is reported as <0.001, while the sponsor's p-value is < 0.001. These are results from distinct calculations and should not be treated as identical estimates of uncertainty. The sponsor's p-value and confidence interval belong to the reported adjusted analysis. Readers should use that analysis when describing the trial's formal primary result, while recognizing that the model details are not fully reported.

14. Multiplicity, Missing Data and Analysis Populations

The registry lists 10 outcome measures and 36 analyses. The primary endpoint is the adjusted mean change from baseline in Schiff Sensitivity Score at Week 12 for Test Dentifrice versus Negative Control Dentifrice. Secondary outcomes include Schiff Sensitivity Score, visual analogue scale, and tactile threshold at several timepoints, with comparisons involving the test, comparator, and negative control dentifrices. Nine secondary outcomes are posted.

When many outcomes, timepoints, or group comparisons are tested, the chance of obtaining at least one apparently notable result by chance can increase. In general, multiplicity procedures can control how results are interpreted across a family of tests. The registry record does not report whether any multiplicity adjustment was planned or applied, how the primary endpoint was distinguished in a formal testing hierarchy, or whether secondary analyses were considered confirmatory or exploratory. The primary p-value should therefore be read as the result for its reported test, without assuming adjustment across all listed analyses.

The primary efficacy population is described as randomized participants who received study treatment at least once and had at least one post-baseline efficacy assessment. This definition identifies who could contribute to the stated efficacy analysis, but the registry record does not report how missing outcome values were handled, whether imputation was used, or how sensitivity to missing data was assessed. It also does not report participant flow or reasons for missing assessments in sufficient detail to evaluate the impact of missingness.

The record names ANCOVA for the primary comparison but does not give the model covariates, diagnostic checks, or detailed statistical plan. Interim analyses and any prespecified stopping rules are not reported in the registry record. The absence of these details limits independent assessment of the complete analysis strategy; it does not establish that a particular method was or was not used.

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.

Most frequent non-serious adverse event terms

The registry reports serious adverse events for the three study arms. There were 0 serious adverse events among 42 participants at risk in the Test Dentifrice group, 0 among 40 in the Comparator Dentifrice group, and 0 among 38 in the Negative Control Dentifrice group. The record reports 0 deaths in each of those groups.

These figures describe the serious adverse events recorded in the registry during the reported study period. A zero count means no serious adverse events were recorded for that group in this listing; it does not establish that an event is impossible or that risks are identical between groups. The number of participants at risk provides context for the counts, but the registry record does not provide a detailed account of surveillance, event definitions, follow-up completeness, or uncertainty around the safety counts.

The record separately lists other adverse events affecting 2 participants in the Test Dentifrice group, 2 in the Comparator Dentifrice group, and 0 in the Negative Control Dentifrice group. Those are not serious adverse events. The registry does not provide terms for serious adverse events because no serious-event terms are listed, and it does not establish from these counts alone whether an event was caused by a dentifrice.

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

The posted primary analysis estimates that the Test Dentifrice group had a greater average decrease in Schiff Sensitivity Score at Week 12 than the Negative Control Dentifrice group. The adjusted mean difference was -0.75, with a 95% confidence interval from -1.01 to -0.48 and p < 0.001. The outcome's scale assigns lower scores to improvement, so the negative contrast points toward a larger average reduction for the test group under the reported analysis.

This is a comparison of group averages on a particular response scale after an air stimulus. It does not describe every participant's experience, and it does not provide an estimate of the probability that a particular participant will have a specific response. The registry does not report a clinically important difference threshold, so the statistical result alone cannot establish the importance of the observed score contrast to participants.

The primary result is specifically a comparison with the Negative Control Dentifrice. Although the record includes a Comparator Dentifrice arm and lists secondary comparisons involving that arm, the primary result should not be interpreted as a direct estimate against every listed dentifrice. The record also does not report enough product details to infer equivalence or identity between arm labels and intervention names beyond what is explicitly stated.

The result is limited to the recorded endpoint and assessment time. The brief summary describes twice-daily brushing over 12 weeks, and the primary endpoint is at Week 12. The registry record does not establish effects beyond that period, explain whether findings apply to people outside the study population, or resolve the unreported details of missing data and multiplicity. Statistical evidence for a difference in this endpoint is not a substitute for those broader questions.

17. Why This Trial Matters Statistically

This trial illustrates why the estimand and its comparator matter. The brief summary describes comparing test fluoride dentifrice with a standard fluoride dentifrice, while the registered primary outcome is explicitly Test Dentifrice versus Negative Control Dentifrice. Different contrasts answer different statistical questions. Naming the actual comparison alongside the endpoint prevents a reader from treating results against one arm as evidence about every arm.

It also illustrates the distinction between a within-group change and a between-group contrast. Both groups had negative mean changes, but the primary question concerns the adjusted difference between their changes. A decrease in each group alone would not establish a difference between groups. The reported adjusted estimate and its interval directly address that comparative question.

The record also demonstrates why adjustment and reproducibility details are important. The sponsor reports an ANCOVA estimate, whereas a summary-statistic recalculation is unadjusted. Those analyses are related but not interchangeable. Without the model terms and missing-data procedures, readers can interpret the posted estimate and interval but cannot fully reproduce the sponsor's calculation.

Finally, statistical significance, precision, and clinical relevance are separate. The reported interval is on one side of zero, but a clinical importance threshold is not reported. Sample-size illustrations based on the observed effect may help explain planning concepts, but they are not the trial's original design justification or evidence of observed power. Keeping those distinctions clear supports a careful reading of clinical trial statistics.

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 registry record leaves several details unavailable for evaluating this trial's results. It does not report the full randomization procedure, allocation concealment, or who was masked. The study is labeled single-masked, but the identity of the masked party and the practical masking procedures are not stated. The record also does not report baseline participant characteristics that would help describe the analyzed groups.

The primary analysis is identified as ANCOVA, but its covariates and full specification are not reported. Missing outcome handling, sensitivity analyses, and the approach to multiple outcomes are also not reported in the registry record. These omissions limit the ability to independently assess the analysis assumptions and robustness of the result. The record reports an efficacy population definition, but not enough participant-flow detail to determine how missing assessments may have affected the analysis.

The primary endpoint uses a defined 0 to 3 score, but a clinically important difference threshold is not reported. The group mean and confidence interval therefore convey statistical differences without establishing their practical importance. The registry also includes a Comparator Dentifrice arm, but the primary comparison is against the Negative Control Dentifrice; results from that primary contrast do not answer all listed pairwise questions.

The study was conducted over a stated 12-week treatment period, and the primary outcome is at Week 12. Longer-term outcomes are not established by this endpoint. The record's original sample-size rationale is not reported; the listed planning figures are based on the observed effect and are not a substitute for that rationale. These limitations concern what can be learned from the registry record and do not by themselves determine the validity of the trial.

19. Related Tutorials

20. Related Statistical Calculators

21. Sources

• ClinicalTrials.gov: Study to Evaluate the Effectiveness of Test Dentifrice in the Relief of Dentinal Hypersensitivity — NCT07317128.
• Registry record last updated 2026-05-13; status last verified 2026-04.
• Results first posted 2026-05-13.
• 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

The registry record describes a completed, randomized, single-masked, parallel-group study of dentifrices for dentin sensitivity, with enrollment of 120. The primary endpoint was adjusted mean change from baseline in Schiff Sensitivity Score at Week 12, comparing Test Dentifrice with Negative Control Dentifrice. Lower scores indicate improvement.

The sponsor reported an ANCOVA adjusted mean difference of -0.75, with a 95% confidence interval from -1.01 to -0.48 and p < 0.001. The primary endpoint figures list 42 participants in the Test Dentifrice group and 38 in the Negative Control Dentifrice group. The registry also lists a Comparator Dentifrice arm and multiple secondary outcomes. Further details about the analysis plan, missing data, multiplicity, and original sample-size justification are not reported in the registry record.