Anticaries Effect of Xylitol,Probiotic and Chlorhexidine Mouth Rinses Among Individuals at High Risk: Complete Statistical Analysis

1. Trial at a Glance

This page covers the registry results for Anticaries Effect of Xylitol,Probiotic and Chlorhexidine Mouth Rinses Among Individuals at High Risk (NCT04399161), a randomized phase 2, phase 3 study. The primary outcome is Change in Streptococcus Mutans Levels in Dental Plaque.

2. Clinical Question

The registered trial title refers to children and elderly people at high risk for dental caries. Its stated rationale concerns bacterial plaque and Streptococcus mutans, described in the record as one of the main pathogens associated with caries. It also presents mouth rinses as adjuncts to oral hygiene and describes chlorhexidine as a reference treatment whose prolonged use can have adverse effects. These points explain the study question; they are not evidence of a comparative result from this trial.

The primary endpoint is a measure of bacterial levels, not a direct record of new cavities or other clinical caries outcomes. The registry record does not report a primary-outcome comparison that would support a conclusion about relative changes between treatments.

3. Trial Design

The registry classifies this as a randomized, double-blind, parallel-group trial and lists its phase as PHASE2 and PHASE3. It is marked completed. The registry enrollment is 60. The record names chlorhexidine mouthwash, xylitol and probiotic as the interventions. Random allocation and double masking are the recorded design features; details about the allocation sequence, concealment, who was masked, or how masking was maintained are not reported in the registry record.

The arm descriptions identify child and elderly cohorts. Each description says that 36 people in that cohort would be recruited or chosen and divided among three groups, with 12 participants per group. These planned figures do not align with the registry enrollment of 60. The record does not explain the difference. The outcome description instead lists group-specific analyzed counts based on groups of 10, with exclusions in several groups. The record does not explain how these planned and analyzed figures relate to the enrollment entry.

The arm descriptions state that participants were asked to rinse once daily at night for 2 minutes using 15 ml of mouth rinse. They do not fully specify the treatment schedule, product composition, adherence assessment, or whether the instructions were identical across all groups. Further details are not reported in the registry record.

The trial dates listed are a start date of 2017-02-15 and a primary completion date of 2017-12-20. These dates describe the registered study timeline; they do not supply information about when each participant was assessed or whether the study followed its planned schedule. The primary outcome is change in Streptococcus mutans levels in dental plaque at 14 days after intervention. The registry record does not report the statistical analysis plan, a sample-size justification, interim analyses, or the method used to compare treatments.

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: Streptococcus mutans count determined in 72 participants Children: 36 of 45 fulfilled eligibility criteria. 6 participants were excluded before allocation (reason: left school). Elderly: 36 of 70 fulfilled eligibility criteria. 6 participants were excluded before allocation (reason: died, didn't co-operate).

Overall Study

Reasons for not completing this period:

Analysis population for the primary outcome, as defined in the registry: Group A (Children): 9 out of 10 analyzed. 1 excluded. Group A (Elderly): 9 out of 10 analyzed. 1 excluded. Group B (Children): 9 out of 10 analyzed. 1 excluded. Group B (Elderly): 9 out of 10 were analyzed. 1 excluded. Group C (Children): All 10 were analyzed. Group C (Elderly): 8 out of 10 were analyzed. 2 excluded.

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: Children (5-12 years) : 30 Elderly (above 60 years) : 30

6. Primary Endpoint

The registry lists the primary outcome as Change in Streptococcus Mutans Levels in Dental Plaque, measured over Assessment of change in Streptococcus mutans levels 14 days after intervention.

The primary endpoint is change in Streptococcus mutans levels in dental plaque, assessed 14 days after intervention. The registry gives the unit as log10CFU/g and identifies the summary measure as a mean with standard deviation. The record describes this measure as a way to determine the antimicrobial efficacy of the mouth rinses.

Bacterial levels are a biological measure related to the trial's stated rationale: the record describes Streptococcus mutans as one of the main pathogens of dental caries. A change in this measure can describe whether bacterial levels shifted during the assessment period. It is not, by itself, a count of cavities or a direct measure of long-term caries experience. The registry record does not report a caries-incidence endpoint among its listed outcome measures.

General statistical context: a mean describes the average measured change within a group, while a standard deviation describes how much individual measurements vary around that average. The log scale expresses bacterial quantity on a transformed scale; interpretation should therefore stay tied to the stated unit and the analysis scale. No conversion to another scale is reported in the registry record.

The outcome description does not state the numerical group means, standard deviations, treatment contrasts, confidence intervals, or p-values. It also does not make clear in the available record how the change was calculated from measurements over time. Accordingly, the endpoint's definition is available, but the magnitude and precision of the results are not reported in the registry record.

7. Why No Re-analysis Is Shown

8. Statistical Interpretation

9. Statistical Methods Explained

The registered design is randomized, double-blind and parallel-group. General statistical context: randomization aims to make treatment groups comparable on average with respect to factors that may affect an outcome. Masking aims to reduce the influence of treatment knowledge on participant behavior, care, or outcome assessment. These are general purposes of the design features; the registry record does not describe the procedures used to implement them or report checks of masking.

The outcome is continuous and summarized as a mean with standard deviation. General statistical context: a mean gives a central summary of measurements, while a standard deviation describes their spread. A standard deviation is not a confidence interval and does not directly quantify the precision of a treatment comparison. Precision for a comparison is commonly communicated using a confidence interval, but no such interval is reported in the registry record.

The outcome unit is log10CFU/g. General statistical context: logarithmic scales are often used for measurements that span a wide range. A difference on a log scale is interpreted on that scale; it should not be casually restated as an absolute count difference. The record does not report a transformation beyond the unit itself, the distribution of measurements, or diagnostic checks for the analysis.

A treatment comparison generally needs an estimate of how outcomes differ between groups, along with uncertainty around that estimate. General statistical context: a confidence interval describes a range of estimates compatible with the observed data under a specified model and its assumptions. A p-value, when reported, addresses compatibility with a specified null hypothesis under the test assumptions; it does not measure the size or clinical importance of an effect. The registry record reports neither comparative estimates nor confidence intervals or p-values, and does not name the statistical test or model.

The trial includes child and elderly descriptions, and the outcome entry lists results by age group and treatment group for the analyzed counts. General statistical context: when a study includes distinct population groups, an analysis may report group-specific results, an overall result, or an interaction assessing whether the treatment contrast differs across populations. Those approaches answer different questions. The registry record does not state which approach was used or provide age-specific estimates. It is not possible to infer whether an overall estimate was adjusted or pooled across age groups.

The outcome record signals that there are several categories or time points and that it was not reduced to one comparison. This matters for interpretation because a collection of analyses can create multiple opportunities to identify an apparently notable result. General statistical context: multiplicity procedures can control the chance of false-positive findings across a defined family of tests, while a prespecified primary comparison can help focus interpretation. The record does not report which comparisons were planned, whether a multiplicity adjustment was used, or how the multiple categories or time points were handled.

The registry gives analyzed counts and exclusions, but not the reasons for missing observations or the analysis population definition. General statistical context: complete-case analysis uses participants with observed outcome data, while other approaches may use statistical models or imputation to address missingness. These approaches rely on different assumptions and can yield different estimates. The registry record does not identify an approach, explain whether exclusions occurred before or after randomization, or state whether participants were analyzed according to their assigned group.

A separate sample-size illustration is described as planning based on the observed effect, with two-sided significance level 0.05, equal allocation between two arms and a normal approximation. It is explicitly a planning illustration, not the trial's own design justification. General statistical context: a planning calculation estimates the number of participants per arm that might be needed to detect a chosen effect under stated assumptions. It is not observed power and does not show that the trial was adequately powered. Since the registry record does not report the observed primary-outcome effect or the trial's sample-size justification, the assumptions and illustration cannot establish the adequacy of the actual design.

The registry lists PHASE2 and PHASE3, a parallel model, randomized allocation and double masking. These labels do not disclose the planned statistical methods. The choice of an analysis should reflect the outcome definition, design, missingness and intended comparison; those details are not reported in the registry record. As a result, the statistical methods used to produce any efficacy conclusion cannot be evaluated from the reported information.

10. Multiplicity, Missing Data and Analysis Populations

The outcome entry indicates that the primary outcome has several categories or time points and was not reduced to one comparison. That creates an interpretation issue: separate tests across outcomes, times or groups can increase the chance that at least one result appears notable by chance. General statistical context: a prespecified primary comparison and an appropriate multiplicity strategy can help address this issue. The registry record does not report the intended family of comparisons, a correction method, or how the outcome categories and time points were analyzed.

The analyzed counts differ across treatment and age groups. Group A children and elderly participants each had 9 out of 10 analyzed, and Group B children and elderly participants each had 9 out of 10 analyzed. Group C children had all 10 analyzed, while Group C elderly participants had 8 out of 10 analyzed. The record states that some participants were excluded but does not report the reasons, timing, or whether missingness was related to treatment or outcome.

General statistical context: missing outcome data can affect both the estimate and its uncertainty, particularly when the probability of missingness is related to participant characteristics or outcomes. Complete-case analysis, imputation and model-based approaches require different assumptions. The registry record does not state which method was used, whether sensitivity analyses were conducted, or how the randomized groups were represented in the analysis.

The registry record does not report a definition of the analysis population, such as whether participants were analyzed according to randomized assignment. It also does not report an intention-to-treat analysis or a per-protocol analysis. The listed analyzed counts alone do not identify the analysis method or establish how the exclusions affected the comparison.

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 5% reporting threshold.

Most frequent non-serious adverse event terms

The serious adverse event entries report 20 at risk and 0 affected in each of the three groups: chlorhexidine mouthwash, xylitol mouth rinse and probiotic mouth rinse. Deaths are reported as 0 in each group. No serious adverse event terms are listed. These are the counts recorded in the registry; the record does not provide additional detail about the event definitions, observation period, or collection procedures.

For other adverse events, the registry reports 20 at risk in each group. The chlorhexidine group has 2 affected, while the xylitol and probiotic groups each have 0 affected. These counts are not a comparative analysis. The record does not report estimates of between-group differences, confidence intervals, or statistical tests for safety outcomes.

General statistical context: an event count describes what was recorded among the participants listed as at risk. A count of zero does not establish that an event is impossible or that no events could occur in a broader population. Interpretation also depends on how events were defined, collected and followed over time. Those details are not reported in the registry record. The entries should therefore be read as the registry's recorded counts rather than as a complete assessment of safety.

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

The record establishes that the trial was designed to compare chlorhexidine, xylitol and probiotic mouth rinses in children and elderly people described as being at high risk for dental caries. It identifies a primary biological outcome: change in dental-plaque Streptococcus mutans levels 14 days after intervention. The design is listed as randomized, double-blind and parallel-group.

Those details do not establish the comparative result. The registry record does not report the group-specific outcome means or standard deviations, a treatment contrast, confidence intervals, or p-values. Without those results, the direction, size and precision of any difference cannot be assessed. The record therefore does not support a statistical conclusion that one rinse produced a greater or smaller change than another.

The endpoint is a measure of bacterial levels, not a direct count of dental caries. General statistical context: a biological marker can be relevant to a disease process without being interchangeable with a clinical outcome. The registry record does not report a caries-incidence result or a longer-term clinical comparison. The 14-day assessment also describes a limited outcome timeframe; it does not establish persistence of any change beyond that assessment.

The safety entries record no serious adverse events or deaths in the listed groups, and report other adverse events in the chlorhexidine group but not the other groups. Those entries are counts, not a formal comparative safety analysis. They cannot by themselves establish the full balance of benefits and harms.

The enrollment entry and planned cohort descriptions do not align, and the record does not explain the difference. The analyzed counts also include exclusions, whose reasons are not reported. These reporting gaps, together with missing outcome estimates and statistical methods, limit what can be concluded from the registry record. The appropriate interpretation is that the trial question and some design and safety information are documented, while the efficacy result and its uncertainty are not reported in the registry record.

13. Why This Trial Matters Statistically

This trial is statistically interesting because it places three active mouth rinses in a randomized, double-blind, parallel-group design and defines a measurable biological outcome. The registry names chlorhexidine, xylitol and probiotic as the treatment groups and focuses on Streptococcus mutans levels in dental plaque. This setup raises a comparative question: how the measured change differs among treatments, and whether that comparison is consistent across the child and elderly populations described.

Answering that question requires more than identifying a primary outcome or recording analyzed counts. A reader needs the group-level outcome summaries, a direct comparison, and an account of uncertainty. The registry record does not report these efficacy results. This illustrates an important statistical distinction: a study design can specify a meaningful question, but the design alone cannot reveal the estimate or how precisely it is known.

The record also makes the analysis population important. It reports exclusions and different analyzed counts by group and age category, but not the reasons for missing outcomes or the method used to handle them. It signals multiple outcome categories or time points without stating how comparisons were selected or adjusted. These details can affect interpretation even when the treatment question and endpoint are clearly stated.

The mismatch between the enrollment entry and the planned cohort descriptions is another reporting issue. Without an explanation, readers cannot reconcile the planned population descriptions with the registry enrollment and analyzed counts. Together, these points show why transparent reporting of participant flow, analysis choices, effect estimates and uncertainty is essential for evaluating a clinical trial statistically.

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 primary limitation for interpreting this trial is that the registry record does not report the numerical primary-outcome results. Group means and standard deviations, treatment contrasts, confidence intervals and p-values are not reported. The magnitude, direction and precision of the antimicrobial outcome therefore cannot be evaluated from the registry record.

The participant numbers are not fully reconciled. The registry enrollment is 60, while the child and elderly arm descriptions each state a planned cohort of 36, divided into three groups of 12. The outcome entry describes analyzed groups based on 10 participants, with different exclusions across age and treatment groups. The record does not explain the discrepancy between these figures, the participant flow, or the reasons for exclusion.

The outcome entry notes multiple categories or time points that were not reduced to one comparison. The record does not report which analyses were prespecified, how multiplicity was addressed, or which analysis produced the reported outcome, if any. The statistical test or model, analysis population, handling of missing data, and any sensitivity analyses are also not reported in the registry record.

Further limitations specific to interpretation include the absence of reported age-group estimates and the lack of detail about how the change in the continuous outcome was calculated. The treatment descriptions are truncated, and the record does not provide full information about intervention composition, adherence, or masking procedures. The primary outcome is a bacterial measure assessed at 14 days; the registry record does not report a caries-incidence outcome or longer-term follow-up result.

15. Related Tutorials

16. Related Statistical Calculators

17. Sources

• ClinicalTrials.gov: Anticaries Effect of Xylitol,Probiotic and Chlorhexidine Mouth Rinses Among Individuals at High Risk — NCT04399161.
• Registry record last updated 2020-07-22; status last verified 2020-07.
• Results first posted 2020-07-22.
• 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 randomized, double-blind, parallel-group trial of chlorhexidine, xylitol and probiotic mouth rinses among children and elderly people at high risk for dental caries. It lists enrollment of 60 and identifies change in dental-plaque Streptococcus mutans levels 14 days after intervention as the primary outcome, measured as a mean with standard deviation in log10CFU/g.

The record reports analyzed counts by treatment and age group, with exclusions in several groups, and adverse-event counts by treatment. It does not report the numerical primary-outcome results, comparative estimates, confidence intervals, p-values, or the statistical analysis method. The planned cohort descriptions and registry enrollment are not reconciled in the record. Consequently, the registry documents the study question and some design details but does not provide enough efficacy results to assess the comparative effect or its precision.