A Study Assessing the Effects of an Experimental Dentifrice in Maintaining Tooth Color Following Tooth Bleaching: Complete Statistical Analysis

1. Trial at a Glance

This page covers the registry results for A Study Assessing the Effects of an Experimental Dentifrice in Maintaining Tooth Color Following Tooth Bleaching (NCT06150573), a randomized na study. The primary outcome is Adjusted Mean VITA Shade Score at 24 Weeks After Tooth Bleaching.

2. Clinical Question

The study’s stated aim was to investigate maintenance of tooth color and reduction of extrinsic dental stain accumulation after peroxide bleaching. The registry identifies the Week 24 adjusted mean VITA shade score as the primary outcome. It also lists secondary measures of VITA shade at Week 12 and Modified Lobene Stain Index scores at Week 12 and Week 24, including site-specific, area, and intensity measures. The posted primary comparison is therefore one part of a broader set of planned outcome measures, but the main interpretation should remain anchored to the designated primary endpoint.

3. Trial Design

The registry describes a randomized, controlled, single-blind, parallel-group clinical study sponsored by HALEON. The study is marked completed and lists enrollment of 160 participants. Its start date is 2023-11-27, and its primary completion date is 2024-07-18. The phase is recorded as not applicable. The conditions listed are dentin sensitivity and oral hygiene.

Participants were assigned to the Test Dentifrice or Reference Dentifrice group. The experimental product contained 5% potassium nitrate, 1% alumina, 5% sodium tripolyphosphate, and 1150 parts per million fluoride as sodium fluoride. The reference product was Aquafresh Cavity Protection, containing 1150 parts per million fluoride as sodium fluoride. Both arm descriptions specify brushing for two timed minutes twice daily, morning and evening, for up to 27 weeks. The descriptions of the precise periods of use around bleaching are cut off in the registry record, so the complete regimen is not reported in the registry record.

The primary endpoint was assessed at Week 24 after tooth bleaching. A single trained clinical examiner visually scored the facial surfaces of the six anterior maxillary teeth using the VITA Bleachedguide 3D-MASTER. The primary analysis population was modified Intent-To-Treat: randomized participants who used study product at least once and had at least one post-bleaching tooth-color assessment. For each specified time point, only participants with data available at that time point were analyzed.

The registry reports an ANOVA comparison of adjusted mean difference for the primary outcome and identifies the analysis as a superiority analysis. Additional details of the trial’s original statistical plan, including the planned sample-size justification and any interim analyses, are not reported in the registry record. The trial enrollment should not be confused with the number contributing to the primary outcome comparison: the posted arm counts for that outcome are 75 and 79, respectively, within the stated analysis population.

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 178 participants were screened into the study, 160 participants were enrolled and randomized to treatment (79 participants in the test dentifrice group and 81 participants in the reference dentifrice group). A total of 154 randomized participants completed the study.

Overall Study

Reasons for not completing this period:

Analysis population for the primary outcome, as defined in the registry: The modified Intent-To-Treat (mITT) population included all randomized participants who completed at least one use of study product and had at least one assessment of tooth color after the bleaching period. Only those participants with data available at the specified time point were 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.

Population: The Safety population comprised all randomized participants who received at least one dose of the study product.

6. Primary Endpoint

The registry lists the primary outcome as Adjusted Mean VITA Shade Score at 24 Weeks After Tooth Bleaching, measured over At Week 24 after tooth bleaching.

The primary endpoint is the adjusted mean VITA shade score at Week 24 after tooth bleaching. The examiner assessed the facial surfaces of the six anterior maxillary teeth with the VITA Bleachedguide 3D-MASTER, an ordered shade scale from 1 (the lightest) to 29 (the darkest). A lower score indicates a lighter shade and is described in the registry as improvement.

A shade score makes tooth color available as a quantitative outcome for comparing the randomized groups at a specified follow-up time. The mean summarizes the group’s scores, while the adjusted mean difference expresses the comparison between groups after the adjustment used in the sponsor’s reported analysis. This endpoint is relevant to the study’s stated question about maintaining tooth color after bleaching. It does not, by itself, measure every aspect of appearance or stain, and it is distinct from the Modified Lobene Stain Index outcomes listed as secondary measures.

Interpretation depends on the direction and precision of the between-group estimate. Because lower scores indicate lighter shades, a negative difference defined as Test Dentifrice minus Reference Dentifrice points toward a lower mean score in the experimental group. The estimate must be considered alongside its confidence interval and the registry’s adjusted analysis; the point estimate alone does not establish a clear difference.

7. Results Posted in the Registry

• Test Dentifrice: mean 12.00 versus 12.06 on control; difference -0.06 (95% CI -1.03 to 0.91), standardized effect d = -0.02; z-test p = 0.904.

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.

Adjusted Mean VITA Shade Score at 12 Weeks After Tooth Bleaching

• 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 errors.
• Result:
  • Test Dentifrice: mean 12.08 versus 11.71 on control; difference 0.37 (95% CI -0.60 to 1.34), standardized effect d = 0.12; z-test p = 0.454.
• Interpretation:
  • The 95% confidence interval includes no difference, so these data do not show a statistically significant difference between Test Dentifrice and the control. The interval gives the range of effects that remain compatible with the data.

The registry lists secondary measures covering VITA shade at Week 12 and Modified Lobene Stain Index outcomes at Week 12 and Week 24. The MLSI outcomes include total scores, scores for gingival, interproximal, and body sites, and separate area and intensity measures. The posted secondary result available for interpretation is the Week 12 VITA comparison. The registry record does not report posted result values for the listed MLSI measures.

The Week 12 VITA comparison has a recalculated unadjusted mean difference of 0.37, with a 95% confidence interval from -0.599 to 1.339 and an unadjusted p-value of 0.454. The sponsor-reported adjusted comparison is 0.37, with a 95% confidence interval from -0.61 to 1.34 and p = 0.458. Both intervals include zero. The point estimate is in the opposite direction from the Week 24 primary point estimate, but neither comparison establishes a clear difference between groups.

These secondary findings do not overturn the primary result. They concern a different follow-up time or different measures, and the available numerical result is only for Week 12 VITA shade. The absence of posted numerical MLSI results means that no overall conclusion about the stain outcomes can be drawn from the registry record. The study’s aim included extrinsic stain accumulation, but an aim is not itself a result.

Secondary outcomes generally carry less inferential weight than a prespecified primary outcome, particularly when several outcomes or time points are examined. Testing many outcomes creates more opportunities for apparently notable results to arise by chance. The registry record does not report whether a multiplicity adjustment was planned or applied. Accordingly, secondary results should be considered exploratory unless the protocol or analysis plan establishes otherwise, and isolated secondary findings should not be treated as confirmatory evidence.

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

• Adjusted Mean VITA Shade Score at 12 Weeks After Tooth Bleaching
• Adjusted Mean Total Modified Lobene Stain Index (MLSI) Score at 12 and 24 Weeks After Tooth Bleaching
• Adjusted Mean MLSI Score at 12 and 24 Weeks After Tooth Bleaching in Gingival Sites, Interproximal Sites and Body Sites
• Adjusted Mean MLSI (Area) Score at 12 and 24 Weeks After Tooth Bleaching
• Adjusted Mean MLSI (Intensity) Score at 12 and 24 Weeks After Tooth Bleaching

9. Statistical Interpretation

10. Statistical Methods Explained

What does a mean difference describe?

A mean is a summary of the observed scores in a group. A mean difference subtracts one group’s mean from the other according to a stated direction. Here, the recalculated difference is Test Dentifrice minus Reference Dentifrice. A negative value therefore means the observed mean score was lower in the experimental group. Since the registry defines lower VITA scores as lighter shades, the sign gives a direction, but it does not by itself tell how certain or important the difference is.

The registry reports least-squares means and a sponsor-reported adjusted mean difference. Least-squares means are model-based group means, taking account of the terms included in the analysis. The full adjustment variables and details of the model specification are not reported in the registry record. The reported primary comparison uses ANOVA, a general method for comparing means through a statistical model. The registry labels the comparison as a superiority analysis. Further details of the planned hypothesis-testing procedure are not reported in the registry record.

What is the recalculation?

The recalculated result is a simple unadjusted comparison constructed from the posted group summaries. It is not a replacement for the sponsor’s adjusted analysis and does not reproduce any adjustment that may have been used in the trial model. The posted group summaries give the Test Dentifrice mean as 12.0 and the Reference Dentifrice mean as 12.06. The recalculated difference is -0.06, with a 95% confidence interval from -1.034 to 0.914 and an unadjusted p-value of 0.904.

The posted arm-level spread is reported as a standard error, rather than as a standard deviation. The recalculation estimates a pooled standard deviation from the reported standard errors and group sizes, so the posted value is marked as approximate. This makes the recalculation useful as a transparent check of the summary data, but it is not equivalent to an analysis of participant-level observations. It cannot account for model covariates or other details absent from the group summaries.

Why are standard errors and standard deviations different?

General statistical explanation: a standard deviation describes the spread of individual observations around a group mean. A standard error describes the uncertainty in an estimated quantity, such as a mean. The standard error of a mean generally becomes smaller as the number of observations contributing to it increases, even if the underlying individual-level variability is unchanged. Therefore, a standard error should not be read as though it were the spread of individual tooth-shade scores. In this result, the recalculation uses the reported standard errors to approximate the underlying spread; that approximation is identified as such.

What does a confidence interval contribute?

General statistical explanation: a confidence interval is a range produced by a method designed to have a stated coverage rate over repeated applications under its assumptions. It conveys the uncertainty around an estimate more directly than a point estimate alone. For a difference, an interval that includes zero is compatible with no difference under the model, while values away from zero indicate the range of differences that remain compatible with the data and method. Such an interval does not assign a probability to a particular fixed effect, and it does not decide whether a difference is practically meaningful.

The recalculated 95% confidence interval includes zero. The sponsor-reported 95% interval also includes zero. The two intervals are similar in their central estimates and overall range, but they arise from different analyses: one is an unadjusted recalculation from summaries, and the other is the reported adjusted ANOVA result. The inferential reading should retain that distinction.

Why does over-dispersion matter?

General statistical explanation: over-dispersion occurs when observed variability is greater than a model assumes. If a model understates variability, standard errors can be too small and confidence intervals too narrow, making results appear more precise than they are. If variability is modeled appropriately, uncertainty estimates better reflect the data. The VITA outcome is analyzed as a continuous score, and the registry identifies the reported dispersion measure as standard error. It does not report an over-dispersion assessment or enough model detail to evaluate one. It would therefore be inappropriate to claim that over-dispersion was present or absent in this analysis.

What does the p-value say?

General statistical explanation: a p-value measures how unusual data at least as incompatible with a specified null model would be if that model and the test assumptions were true. It is not the probability that the null hypothesis is true, the probability that the result occurred by chance, or a measure of clinical importance. The recalculated unadjusted p-value is 0.904; the sponsor’s reported p-value is 0.914. Both are consistent with the confidence intervals’ inclusion of zero, but neither establishes equivalence or proves that the groups have exactly the same mean.

The trial’s own original sample-size assumptions, missing-data procedures beyond the stated available-case rule, full adjustment variables, and any interim analyses are not reported in the registry record. Those omissions limit how fully the analysis can be reconstructed or assessed from the registry entry alone.

11. Confidence Intervals and Precision

Precision is reflected in how narrowly an estimate is bounded by its confidence interval. For the primary outcome, the recalculated unadjusted mean difference is -0.06, with a 95% confidence interval from -1.034 to 0.914. The sponsor-reported adjusted mean difference is -0.05, with a 95% confidence interval from -1.04 to 0.93. Both intervals include zero and extend to differences on either side of it. The result is therefore not precise enough to determine the direction of a small difference with confidence.

The intervals also communicate that the data are compatible with a range of possible differences, rather than only the point estimate. A point estimate close to zero should not be read as proof that the true difference is exactly zero. Conversely, because the interval covers zero, it does not support a definite claim of a difference in either direction. The registry does not report a threshold for a clinically meaningful difference on this scale, so the intervals cannot be classified against such a threshold.

The recalculated interval is based on an approximate pooled standard deviation derived from posted standard errors and group sizes. The sponsor’s adjusted interval comes from the registry-reported ANOVA analysis. Their similar estimates and intervals provide a consistent broad reading of the primary comparison, while their different methods mean they should not be treated as duplicate calculations. Confidence intervals describe statistical uncertainty under their respective methods; they do not capture every possible source of bias, measurement error, or limitation in generalizability.

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 calculations. For these continuous outcomes, the values are participants per arm, rather than total event counts. The planning 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 set to 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 illustrative number of participants per arm for a design with an 80% chance of detecting the specified effect under the stated assumptions, if that effect and the assumptions were correct. The 90% power column gives the corresponding planning number for a design with a 90% chance under those same assumptions. These are prospective planning quantities, not descriptions of the likelihood that the completed study detected an effect. This is not observed power.

The rows vary the effect used for planning. Planning for 100% of the observed effect uses the full observed estimate; the other rows consider 75% and 50% of that estimate. Smaller effects are harder to distinguish from random variation, so they require more participants per arm to attain the same target power. This explains why the illustrated participant counts increase as the assumed effect becomes smaller.

The primary observed difference is close to zero, and the resulting illustrations are especially sensitive to the effect chosen for planning. They should not be interpreted as a recommendation for a future study or as evidence about what the original investigators planned. The calculations are based on a simple planning framework and do not incorporate unreported design features, adjustments, missingness assumptions, or other elements of the original protocol.

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 = -0.060; pooled standard deviation σ = 3.084.
2. n = 2 × (1.96 + 0.842)² × 3.084² / -0.060² = 41,472.9, rounded up to 41,473 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 <- -0.0600000000000005                      # observed difference in means
sigma <- 3.0840011583553                     # 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(6150573)
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 = 41,473 (80% power), 55,521 (90% power)
 75% of observed effect: n per arm = 73,730 (80% power), 98,703 (90% power)
 50% of observed effect: n per arm = 165,892 (80% power), 222,082 (90% power)
power.t.test: 41473.8 
Simulated power at n = 41,473 per arm: 0.802 (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. Analyses Reported by the Sponsor

The registry’s sponsor-reported primary analysis is an ANOVA comparison of adjusted means. It reports an adjusted mean difference of -0.05, a 95% confidence interval from -1.04 to 0.93, and p = 0.914. The recalculated comparison uses the posted group means and standard errors without adjustment. It gives a mean difference of -0.06, a 95% confidence interval from -1.034 to 0.914, and an unadjusted p-value of 0.904.

The close estimates point to a similar broad interpretation: both are near zero, both confidence intervals include zero, and neither analysis establishes a clear between-group difference in the primary score. However, the calculations are not interchangeable. Adjustment can change an estimate and its uncertainty, and the recalculation cannot recreate the sponsor’s model from aggregate summaries. The full adjustment specification is not reported in the registry record.

The recalculation is a supplementary check, not a substitute for the trial’s reported analysis. The sponsor’s reported result should be read as the study’s own inferential analysis, while the unadjusted calculation helps show how the posted arm summaries compare without model adjustment. No discrepancy is flagged between the recalculation and the sponsor’s analysis in the registry-derived data, but their slightly different values remain attributable to their different methods and rounding.

15. Multiplicity, Missing Data and Analysis Populations

The registry identifies one primary outcome at Week 24 and lists multiple secondary outcomes, including tooth shade and several stain measures at different time points or sites. When several outcomes are tested, the chance of at least one apparently unusual result can increase. Statistical procedures can control this multiplicity, for example by adjusting the interpretation or significance threshold across a defined family of tests. Whether such a procedure was specified or used is not reported in the registry record.

The primary sponsor-reported analysis is identified as an ANOVA superiority comparison. The registry entry does not provide the full statistical analysis plan, the family of hypotheses, any multiplicity strategy, or details of interim analyses. It is therefore not possible to determine from the record whether the reported p-values were adjusted for multiple comparisons. The primary endpoint should be distinguished from the secondary measures, and the unadjusted secondary result should be interpreted cautiously in light of the number of outcomes examined.

The primary analysis population is described as modified Intent-To-Treat. It included randomized participants who completed at least one use of study product and had at least one post-bleaching tooth-color assessment. The registry further states that only participants with data available at the specified time point were analyzed. This indicates an available-data approach at each outcome time, but the reasons for missing observations, the amount of missingness by cause, and any methods used to address missing data are not reported in the registry record.

Missingness can affect interpretation if the participants with observed outcomes differ systematically from those without them. The registry’s population definition does not establish whether missing data were balanced between groups or whether a sensitivity analysis was conducted. The primary posted group counts are 75 and 79, while total enrollment is 160; these figures alone do not explain the difference or establish why any participant did not contribute to the primary endpoint.

The record also does not report the original sample-size justification, the assumptions used to plan the trial, or whether an interim analysis was conducted. These details matter for assessing the prespecified analysis and the context in which the primary result was interpreted. In their absence, the posted results can be described, but the full analysis strategy cannot be reconstructed.

16. 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 serious adverse event terms

Most frequent non-serious adverse event terms

Serious events with the highest arm-level rate: transient ischaemic attack (1.3%), pulmonary embolism (1.2%).

The safety figures describe participants at risk and counts with serious adverse events, other adverse events, and deaths. In the Test Dentifrice group, 79 participants were at risk for serious adverse events and 1 was affected; 79 were at risk for other adverse events and 39 were affected. In the Reference Dentifrice group, 81 participants were at risk for serious adverse events and 1 was affected; 81 were at risk for other adverse events and 42 were affected. The registry reports 0 deaths in each group.

The registry also lists TRANSIENT ISCHAEMIC ATTACK at 1.3% and PULMONARY EMBOLISM at 1.2% among the top serious-event terms. The relationship of those percentages to specific groups or a particular denominator is not reported in the registry record. The event counts should be read as descriptive summaries. They do not, by themselves, establish whether an event was caused by a dentifrice or whether the groups differ in safety.

These totals do not provide event timing, duration, severity detail beyond the serious/non-serious grouping, or a full account of how events were assessed. The registry record therefore supports a description of the posted counts, not a causal conclusion or a complete safety assessment.

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

The primary results describe a comparison of mean tooth-shade scores at Week 24 after bleaching. The sponsor-reported adjusted estimate is -0.05 for Test Dentifrice relative to Reference Dentifrice, with a 95% confidence interval from -1.04 to 0.93. The recalculated unadjusted estimate is -0.06, with a 95% confidence interval from -1.034 to 0.914. Both intervals include zero, so the posted results do not establish a clear between-group difference in the primary score.

This is not proof that the products have identical effects. The confidence intervals include a range of possible differences, and the registry does not state a threshold for a meaningful change in shade score. Nor does the result establish that either group did or did not maintain tooth color in an absolute sense: the principal analysis reported is a comparison between groups at a follow-up time, not a conclusion about each group’s change from baseline.

The finding is specific to the defined VITA score, the Week 24 time point, and the modified Intent-To-Treat participants with data available then. It does not answer every question about extrinsic stain accumulation, because the registry lists several stain outcomes but does not report their numerical results in the record summarized by the posted data. The Week 12 VITA comparison is a secondary result and also has an interval including zero.

Statistical uncertainty is only one part of interpretation. The registry does not report a meaningful-difference threshold, complete missing-data methods, full model adjustments, or a multiplicity strategy. These gaps limit the strength of conclusions that can be drawn from the record. The safety counts are also descriptive and do not establish causality. No medical recommendation follows from these statistical results.

18. Why This Trial Matters Statistically

This trial illustrates why a point estimate should be read together with its uncertainty interval. The primary estimate is close to zero, but the intervals span values in both directions. Reporting only the group means or only the p-value would conceal how much uncertainty remains about the between-group difference.

It also shows the distinction between an adjusted trial analysis and a simple recalculation from aggregate summaries. The sponsor-reported ANOVA and the unadjusted recalculation lead to a similar broad reading, but they answer the comparison through different methods. The latter is useful as a transparent check; it cannot recover the full participant-level model or replace the trial’s reported analysis.

The registry lists a broader set of outcomes than the primary tooth-shade measure. Secondary outcomes can add context, but multiple measures and time points make prespecification and multiplicity handling important. The absence of posted MLSI numerical results and the lack of a reported multiplicity strategy constrain how much can be inferred about stain outcomes.

Finally, enrollment and endpoint analysis counts are not the same quantity. The registry reports enrollment of 160 and primary endpoint group counts of 75 and 79. The stated population and time-point availability rule clarify who could contribute, but the record does not explain the reasons for participants’ non-contribution. This distinction matters when evaluating the scope and precision of the evidence rather than treating enrollment alone as the effective sample for every outcome.

19. 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 primary endpoint is a visually assessed shade score. The registry states that a single trained clinical examiner used the VITA Bleachedguide 3D-MASTER, but does not report examiner reliability, repeatability assessments, or procedures for resolving uncertain scores. The outcome is an ordered shade scale, while the reported analysis summarizes it through means. Details about the model’s handling of the scale and its distribution are not reported in the registry record.

The registry describes the study as single-blind but does not identify which study participants or personnel were blinded. The full protocol and details of allocation concealment are not reported in the registry record. The descriptions of the products’ use around bleaching are truncated, so the complete timing and adherence expectations cannot be reconstructed. These limitations affect how fully the conduct of the comparison can be assessed from the record.

The primary endpoint analysis used 75 participants in the Test Dentifrice group and 79 in the Reference Dentifrice group, compared with enrollment of 160. The stated available-data rule does not explain why the remaining enrolled participants are not represented in those endpoint counts. Reasons for missing data, adherence, withdrawals, and sensitivity analyses are not reported in the registry record. The effect of any missingness on the estimate cannot therefore be evaluated from these numbers alone.

The result is limited to the Week 24 primary score and does not supply numerical results for the listed MLSI outcomes. A multiplicity strategy, the original sample-size justification, full model adjustment details, and interim analyses are not reported in the registry record. The approximate unadjusted recalculation also relies on summary standard errors rather than participant-level data. Together, these limitations constrain reconstruction of the analysis and the scope of conclusions from the posted record.

20. Related Tutorials

21. Related Statistical Calculators

22. Sources

• ClinicalTrials.gov: A Study Assessing the Effects of an Experimental Dentifrice in Maintaining Tooth Color Following Tooth Bleaching — NCT06150573.
• Registry record last updated 2025-07-24; status last verified 2025-07.
• Results first posted 2025-07-24.
• 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.

23. Record Summary

NCT06150573 is a completed, randomized, controlled, single-blind, parallel-group study sponsored by HALEON, with enrollment of 160. It compared an experimental dentifrice containing potassium nitrate, alumina, sodium tripolyphosphate, and fluoride with a fluoride reference dentifrice after peroxide tooth bleaching.

The primary outcome was adjusted mean VITA shade score at Week 24. The sponsor-reported adjusted difference was -0.05, with a 95% confidence interval from -1.04 to 0.93 and p = 0.914. The unadjusted recalculation was -0.06, with a 95% confidence interval from -1.034 to 0.914 and p = 0.904. Both intervals include zero. The record lists secondary shade and stain outcomes, but numerical MLSI results are not reported in the registry record. The primary population included randomized participants with study-product use and post-bleaching tooth-color data, with only available observations analyzed at each time point.