This page provides an independent statistical analysis and educational interpretation of publicly reported results. ClinicalTrials.gov provides the official trial registry record. Numerical trial results on this page are restricted to the results posted in the ClinicalTrials.gov record; calculations added by Clinical Biostats are labelled as such.
1. Trial at a Glance
This page covers the registry results for Reducing Bacteria That Cause Tooth Decay (NCT03062605), a randomized phase 3 study. The primary outcome is Microbial Levels.
| Feature | Registry value |
|---|---|
| ClinicalTrials.gov identifier | NCT03062605 |
| Phase | Phase 3 |
| Condition | Caries, Dental, Cariostatic Agents |
| Allocation | Randomized |
| Design model | Parallel |
| Masking | Single |
| Enrollment | 48 |
| Arms in the primary outcome | n/a |
| Lead sponsor | University of California, Los Angeles |
| Results posted | Yes |
2. Clinical Question
Population
Adults at high caries risk were the intended population, according to the study summary. The registry record reports an enrollment of 48 participants but does not report further eligibility details or participant characteristics.
Intervention
The treatment group rinsed with 0.3% NaOCl for one minute, followed by a rinse with 10% iodine for one minute. The procedure was performed once at baseline.
Comparator
The control group received a 10% iodine rinse for one minute, also once at baseline. The registry describes this as a positive control.
Primary question
The study asked whether adding the NaOCl rinse before iodine was associated with lower microbial levels than iodine alone. The proposed mechanism was that NaOCl would disrupt microbial biofilm and make iodine more effective. The registry record does not report the primary outcome results, so the direction or size of any difference cannot be established from the posted record.
The study’s summary describes saliva sampling at baseline, one week, one month, two months and three months. It identifies mutans Streptococci as the main germs of interest and describes testing with two commercial methods. The primary outcome description, however, concerns CRT® Bacteria results for S. mutans and Lactobacillus, with the primary timeframe listed as baseline and 12 weeks. The record does not provide the microbial counts or a treatment comparison for those measurements.
Accordingly, the clinical question is clear at the level of treatment assignment and intended biological outcome, but not answerable from the outcome results in the registry record. No conclusion about the observed effect can be drawn without those results.
3. Trial Design
The registry classifies this as a Phase 3, randomized, single-masked, parallel-group study. Participants were assigned to the two rinse groups and remained in their assigned groups for the three-month study duration. The record gives an enrollment of 48 and identifies the University of California, Los Angeles as sponsor. The study status is completed.
The two groups differed in whether NaOCl preceded the iodine rinse. Treatment participants used 0.3% NaOCl for one minute and then 10% iodine for one minute. Control participants used 10% iodine for one minute. Both procedures were performed once at baseline, rather than repeatedly throughout follow-up. The control is described as a positive control, meaning that the comparison was against an active rinse rather than an untreated group.
The summary gives a broad saliva-sampling schedule of baseline, one week, one month, two months and three months. The primary outcome timeframe is listed as baseline and 12 weeks. These time descriptions are compatible with a study following participants over approximately three months, but the record does not explain how every scheduled sample relates to the primary analysis.
Single masking is reported, but the identity of the masked party or parties is not reported in the registry record. The randomization method, allocation concealment procedures, and details of how participants were assigned are also not reported in the registry record. The record does not describe protocol deviations, adherence to the rinse procedures, or whether any participants changed groups. These details matter because the effect estimate depends not only on random assignment but also on how assignment and follow-up were carried out.
The primary outcome population is defined as participants retained in the study for whom CRT results were available. The registry does not give the number analyzed for the primary outcome by group. Although the study has four analyses listed, their definitions and results are not reported in the registry record. Consequently, the design can be described, but the analysis population and the results for each group cannot be reconstructed from the 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
| Stage | Treatment(TX) | Control (CT) |
|---|---|---|
| STARTED | 25 | 23 |
| COMPLETED | 14 | 13 |
| NOT COMPLETED | 11 | 10 |
Analysis population for the primary outcome, as defined in the registry: Number analyzed includes participants retained in the study for whom CRT results were available
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.
| Characteristic | Unit | Treatment(TX) | Control (CT) | Total |
|---|---|---|---|---|
| Participants analysed | 25 | 23 | 48 | |
| Age, Continuous | years | 40.4 (SD 10.2) | 38.2 (SD 6.6) | 39.4 (SD 8.6) |
| Sex: Female, Male: Female | Participants | 15 | 18 | 33 |
| Sex: Female, Male: Male | Participants | 10 | 5 | 15 |
| Race and Ethnicity Not Collected | Participants | — | — | 0 |
| Region of Enrollment: United States | participants | 25 | 23 | 48 |
6. Primary Endpoint
The registry lists the primary outcome as Microbial Levels, measured over Baseline, 12 weeks.
| Element | Registry entry |
|---|---|
| Result type | Count Of Participants |
| Measure of spread | not applicable |
| Unit | Participants |
| Endpoint classification | Binary Endpoint |
The primary outcome is titled Microbial Levels and is recorded as a count of participants. Its description says that saliva was tested with CRT® Bacteria culture media specific to S. mutans and Lactobacillus. After incubation for three days, the colonies are compared with photographic standards. The stated primary timeframe is baseline and 12 weeks.
The study summary describes these bacteria as strongly associated with tooth decay and frames microbial reduction as the purpose of the rinse comparison. Saliva sampling therefore provides a way to assess microbial findings over follow-up without relying only on a clinical examination of teeth and gums. The registry also describes a separate CariScreen bioluminescence assay for total organisms, but the stated primary endpoint description concerns the CRT culture test.
There is an important distinction between measuring microbial levels and reporting a count of participants. A count of participants is not itself a microbial concentration or a change in microbial burden. The record does not state the categories used to classify CRT results, the threshold for any category, or the group counts for each category at baseline and 12 weeks. It also does not report a numerical treatment effect or its uncertainty. The primary outcome results are therefore not reported in the registry record in a form that allows the contrast between groups to be interpreted.
7. Why No Re-analysis Is Shown
8. Statistical Interpretation
The registry describes a randomized comparison of two active rinse procedures and a biologically focused outcome. The treatment group received NaOCl followed by iodine, while the control group received iodine alone. Because both groups received iodine, the intended contrast is the incremental contribution of adding NaOCl before the iodine rinse, rather than a comparison between rinsing and no rinsing.
The study summary states the hypothesis that the two-step procedure would yield lower microbial counts. That is the planned expectation, not a reported finding. The registry record does not report the CRT results by group, a treatment-effect estimate, a confidence interval, or a statistical test for the primary outcome. The observed direction, magnitude, and precision of the comparison cannot therefore be described. It would be inappropriate to infer that the hypothesis was supported or not supported from the study design or from the adverse-event counts.
The primary outcome is described as a count of participants, with baseline and 12-week measurements, but the result categories and counts are absent. The record also describes additional saliva-sampling occasions and a second microbial testing method. It does not provide results from those assessments, so they cannot clarify the primary comparison or establish whether any pattern was consistent over follow-up.
Precision is normally assessed using an uncertainty interval around an estimated contrast. Such an interval indicates the range of effect sizes compatible with the data under the analysis assumptions; it does not by itself establish whether an effect is important. No interval is reported for this primary outcome. Without an estimate and its uncertainty, neither the apparent size of a difference nor the degree of precision can be assessed.
The registry lists 48 participants enrolled, but enrollment is not the same as the number included in the primary analysis. The primary analysis population is defined as participants retained with available CRT results, and the numbers meeting that definition are not reported in the registry record. Thus the enrollment figure alone cannot establish how much outcome information was available or whether missing measurements differed between groups.
The appropriate interpretation is limited: the record identifies the trial question, groups, endpoint description and follow-up schedule, but does not report the primary results needed to answer the question. No effectiveness conclusion follows from the information recorded.
9. Statistical Methods Explained
Randomization is used to create groups whose differences at the start of a study are expected, on average, to be due to chance rather than deliberate selection. This can support a causal comparison when assignment is implemented as planned and outcome data are collected and analyzed appropriately. The registry identifies the study as randomized, but the sequence-generation and allocation-concealment methods are not reported in the registry record. Those details would help readers assess how assignment was produced and whether it could have been anticipated.
What the randomized contrast represents
The comparison is between a two-step rinse and an iodine-only rinse. Since the control is active, the contrast addresses the additional effect associated with including NaOCl before iodine, under the study conditions. It does not directly compare either rinse with no treatment. The procedures were performed once at baseline, while microbial samples were scheduled during follow-up. The study summary describes the proposed biofilm-disruption explanation as a hypothesis; a hypothesized mechanism is not evidence that the mechanism occurred.
What a confidence interval would add
General statistical explanation: an effect estimate describes the observed contrast between groups, while a confidence interval communicates uncertainty around that estimate under the chosen model and assumptions. A narrow interval indicates greater statistical precision than a wide interval, but precision is not the same as clinical importance. An interval can include effects in more than one direction, and its interpretation depends on the endpoint definition and analysis. The registry record does not report a primary effect estimate or confidence interval, so precision cannot be evaluated for this trial.
Why outcome definition matters
The primary outcome is titled Microbial Levels, but its parameter is a count of participants. The description identifies culture results for S. mutans and Lactobacillus, yet does not specify the result categories or the rule used to classify participants. A count endpoint may require comparison of category frequencies, whereas a continuous microbial measurement could be analyzed using differences in measured levels. These are different outcome structures and can produce different effect measures. The record does not establish which categories or comparison were used, so no specific model or effect measure can be attributed to the trial.
General statistical explanation: the model should reflect the outcome scale and how observations are collected. For categorical participant counts, an analysis may compare the distribution of participants across outcome categories. Repeated measurements from the same participant are correlated, so treating each time point as if it came from an unrelated participant can understate uncertainty. A longitudinal analysis can account for within-participant correlation, but the model, correlation structure, and handling of time are not reported in the registry record. No particular analysis method should be inferred.
Why variability and over-dispersion can matter
General statistical explanation: count data may vary more than a simple model assumes. This is called over-dispersion. If it is ignored, standard errors and confidence intervals may be too optimistic. The relevance of over-dispersion depends on the actual outcome and model. Here, the primary outcome is listed as a participant count, while the study description also refers to microbial counts. The registry does not report the underlying data or model, so it is not possible to determine whether over-dispersion was relevant to the analysis.
Planning assumptions are not trial results
The record describes a planning illustration based on the observed effect, using a two-sided significance level of 0.05, equal allocation, and a normal approximation; its effect to detect is expressed as a stated fraction of the observed effect. These are planning assumptions, not evidence that the trial was designed with those assumptions. The actual sample-size justification and design assumptions are not reported in the registry record. Planning sample sizes are illustrations of how assumptions affect required enrollment; they are not observed power and do not show that a study can detect or exclude a treatment effect.
General statistical explanation: a significance test and an effect estimate answer different questions. A test evaluates compatibility with a specified null hypothesis under a statistical model, while the estimate and interval convey the scale and precision of the observed contrast. A threshold-based test result alone would not indicate whether a difference is large or important. In this record, no primary test result or estimate is reported, so neither type of inference is available.
10. Multiplicity, Missing Data and Analysis Populations
The study summary describes saliva samples at baseline, one week, one month, two months and three months, and mentions two commercial testing methods. The primary outcome timeframe is listed as baseline and 12 weeks. Considering several time points, microbial measures, or outcome categories can create multiple opportunities to identify an apparently notable result. Statistical multiplicity refers to the increased chance of false-positive findings when many hypotheses are tested without an appropriate strategy.
The registry lists four analyses, but the analysis definitions, which outcome or time point each addresses, and any multiplicity adjustment are not reported in the registry record. It is therefore not possible to determine whether there was a prespecified primary comparison or how secondary comparisons were handled. No claim should be made that a multiplicity correction was or was not used.
Missing data also affect interpretation. The primary outcome population includes participants retained in the study who had CRT results available. The record does not report the number with available results by group, reasons for missing results, or how missing measurements were handled. If availability differs between groups or is related to microbial status, a complete-case comparison may not represent the randomized groups as a whole. This is a general concern, not evidence that such a pattern occurred in this trial.
The registry does not report an intention-to-treat analysis population, an imputation method, or sensitivity analyses for missing outcomes. It also does not report whether all scheduled saliva samples were obtained. Without these details and the group-specific analysis counts, the extent to which missingness or multiplicity affects the primary inference cannot be assessed.
11. Safety Results
The registry reports serious adverse events as affected participants divided by participants at risk.
| Arm | Participants with serious adverse events | Participants at risk | Percentage |
|---|---|---|---|
| Treatment(TX) | 0 | 25 | 0.0% |
| Control (CT) | 0 | 23 | 0.0% |
Other (non-serious) adverse events
Participants with at least one non-serious event at or above the registry's 5% reporting threshold.
| Arm | Participants affected of at risk |
|---|---|
| Treatment(TX) | 0 of 25 |
| Control (CT) | 0 of 23 |
The registry reports zero participants with serious adverse events among 25 at risk in the treatment group and zero among 23 at risk in the control group. It also reports zero participants with other adverse events among 25 at risk in the treatment group and zero among 23 at risk in the control group. These are the posted event counts for the listed groups.
Zero reported events should be read as the registry’s recorded count, not as proof that no symptoms or harms occurred. The record does not report event descriptions, collection procedures, follow-up completeness for safety, or whether any events were considered related to a rinse. Death counts are not reported in the registry record; the absence of a numerical death count is not equivalent to a reported zero.
These safety figures do not answer the microbial outcome question. They also do not establish the safety profile beyond the participants and follow-up represented in this trial record. The study’s primary endpoint is microbial levels, and its numerical results are not reported in the registry record.
12. What the Result Does, and Does Not, Mean
The study addresses a focused comparison: whether one baseline rinse with NaOCl followed by iodine produces different microbial findings from one baseline iodine rinse. Its randomized, parallel-group design is intended to compare those assigned procedures over the study follow-up. The study summary gives a biological rationale for adding NaOCl and describes repeated saliva sampling.
What the registry record does not establish is whether microbial levels were lower in either group, how large any difference was, or how precisely it was estimated. The primary results, outcome categories, and group-specific counts are not reported in the registry record. There is no reported effect estimate or confidence interval from which to judge the size or uncertainty of the contrast. Therefore, the trial’s stated hypothesis must not be mistaken for an observed result.
The design also defines the scope of the question. The comparison is between two active procedures, not between a rinse and no rinse. The intervention was given once at baseline, and the outcome description concerns CRT culture findings at baseline and 12 weeks. The summary’s additional sampling times and CariScreen method broaden the planned assessment, but their results are not reported in the registry record.
The enrollment of 48 participants is not enough to determine the amount of analyzable outcome data. The primary outcome population is defined by retention and availability of CRT results, and the number analyzed in each group is not reported. The record likewise does not specify the analysis model, missing-data procedures, or the plan for handling multiple outcomes and time points. Those uncertainties constrain any assessment of bias and precision.
In practical statistical terms, the record documents what investigators set out to compare, but it does not provide the result needed to decide what the comparison showed. The available information cannot support a claim that the two-step procedure reduced microbial levels, nor a claim that it did not. It also cannot support a conclusion about the magnitude, persistence, or clinical importance of any possible difference.
13. Why This Trial Matters Statistically
This trial is statistically instructive because the intervention contrast and biological rationale are easy to state, while the registry record does not include the outcome results needed to evaluate the hypothesis. A clear question and a randomized design are important, but they do not substitute for reporting group-specific outcome data, an effect estimate, and its uncertainty.
The outcome description also illustrates why endpoint specification matters. The study concerns microbial levels, but the primary parameter is listed as a count of participants. Without the result categories and classification rules, readers cannot tell exactly what the participant counts represent or what comparison would answer the clinical question. A well-defined endpoint connects the laboratory measurement to the statistical analysis and makes the result interpretable.
Follow-up creates another statistical consideration. The study summary lists several saliva-sampling occasions and two testing methods, while the primary timeframe specifies baseline and 12 weeks. When multiple outcomes and time points are available, a prespecified analysis plan helps distinguish the principal comparison from exploratory findings and helps readers understand how multiplicity was addressed. The registry does not report those analysis details.
Finally, the definition of the analyzed population depends on retention and availability of CRT results. Reporting how many participants contributed outcome data in each group, and how missing measurements were handled, is necessary for judging whether the analysis reflects the randomized comparison. The trial therefore highlights a general principle: interpretation depends on transparent reporting of the endpoint, analysis population, missingness, and uncertainty, as well as the study design.
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 most consequential limitation for interpreting this record is that primary outcome results are not reported in the registry record. There are no group-specific CRT counts, effect estimates, confidence intervals, or primary statistical test results. The listed outcome is a participant count, but its categories and thresholds are not described. The observed difference and its precision therefore cannot be assessed.
The record defines the primary analysis population as participants retained with available CRT results, but does not report how many participants met that definition in each group. Reasons for missing results and the methods used to handle missing data are not reported in the registry record. The enrollment figure alone cannot resolve this limitation.
Although four analyses are listed and the study summary describes several time points and two tests, the analysis-specific definitions and results are absent. The multiplicity strategy, statistical model, and treatment of repeated measurements are not reported in the registry record. This prevents assessment of whether the analysis matched the endpoint structure and how uncertainty was calculated.
Other trial details that would aid appraisal are also absent, including the randomization procedure, allocation concealment, identity of the masked party, participant characteristics, and protocol adherence. The registry describes a positive-control comparison and a single baseline rinse, but does not report whether participants followed the procedures as intended. These are reporting limitations in the available record; they do not establish that the trial itself lacked these procedures.
15. Related Tutorials
16. Related Statistical Calculators
17. Sources
- ClinicalTrials.gov: Reducing Bacteria That Cause Tooth Decay — NCT03062605.
- Registry record last updated 2019-12-24; status last verified 2019-12.
- Results first posted 2019-12-24.
- 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.
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Use this trial's endpoint as a starting point for deeper study of effect measures, confidence intervals, and sample-size planning.
18. Record Summary
The registry record describes a completed Phase 3, randomized, single-masked, parallel-group study with enrollment of 48. The treatment group received 0.3% NaOCl followed by 10% iodine; the positive-control group received 10% iodine. Each rinse procedure was performed once at baseline. The study concerned microbial findings in saliva during follow-up, with the primary outcome described as a count of participants with CRT results at baseline and 12 weeks.
The record reports zero serious and zero other adverse-event participants in each group, with 25 at risk in treatment and 23 at risk in control. It does not report the primary microbial results, group-specific primary analysis counts, effect estimate, or uncertainty interval. The registry record therefore documents the comparison and its intended endpoint, but does not allow the treatment contrast to be evaluated.