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 Clinical Evaluation of Lava Digital Veneer System (DVS) Crowns (NCT01278862), a randomized na study. The primary outcome is Clinical Performance of Crowns Via Modified United States Public Health Service (USPHS) Criteria.
| Feature | Registry value |
|---|---|
| ClinicalTrials.gov identifier | NCT01278862 |
| Phase | NA |
| Condition | Decay |
| Allocation | Randomized |
| Design model | Parallel |
| Masking | None (open label) |
| Enrollment | 77 |
| Arms in the primary outcome | n/a |
| Lead sponsor | Solventum US LLC |
| Results posted | Yes |
2. Clinical Question
Population
The study concerned crowns evaluated in vivo in people with decay. The registry describes the primary outcome population as crowns evaluated within each group after 1 year. Total enrollment was 77, while the outcome unit is crowns; the relationship between participant counts and crown counts is not reported in the registry record.
Intervention
The intervention was the DVS veneer: a porcelain veneer made by a CAD/CAM method for a Lava crown. The study summary describes the crown as made using computer-aided design and computer-aided machining, with the veneer itself milled using CAD/CAM.
Comparator
The comparator was the Conventional Veneer, described as a veneer made by a laboratory technician. The study summary characterizes it as a hand-fabricated porcelain covering on a similar CAD/CAM Lava crown.
Primary question
At 1 year, what proportion of crowns in each group had perfect, or alpha/A, scores under the modified USPHS criteria? Those criteria cover color match, margin adaptation and discoloration, surface finish, crown fracture, proximal contact, sensitivity, and caries. The registry record does not report the group outcome values or a single comparison across these criteria.
3. Trial Design
This was a randomized, parallel-group device study comparing the DVS veneer with the Conventional Veneer. The record lists allocation as randomized and masking as none. It does not report how the random sequence was generated, whether allocation was concealed, or who knew the assigned veneer during treatment or assessment. Those details should not be inferred from the design labels alone.
The study enrolled 77 participants and was marked terminated. Its recorded start was 2010-11 and its primary completion was 2014-03. The phase is listed as NA. The registry record does not report why the study was terminated, whether termination affected follow-up or data collection, or whether the recorded completion corresponds to completion of every planned analysis.
The study aim was to compare CAD/CAM-veneered Lava crowns with similar CAD/CAM Lava crowns covered by hand-fabricated porcelain. The primary outcome was clinical performance assessed with modified USPHS criteria, with a timeframe of 1 year. Its unit is crowns rather than participants. The registry record does not describe how many crowns each participant could contribute or how multiple crowns from the same participant, if any, were handled analytically.
The record lists 2 outcome measures and 7 analyses. It does not provide a detailed analysis plan, a sample-size justification, or a description of the analysis populations. The primary outcome has multiple clinical criteria, and the record does not reduce them to a single comparison. Consequently, the design information identifies the broad comparison and assessment framework, but does not establish the complete planned or conducted statistical procedure.
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 | DVS Veneer | Conventional Veneer |
|---|---|---|
| STARTED | 45 | 43 |
| COMPLETED | 44 | 42 |
| NOT COMPLETED | 1 | 1 |
Reasons for not completing this period:
| Reason | DVS Veneer | Conventional Veneer |
|---|---|---|
| Lost to Follow-up | 1 | 1 |
Analysis population for the primary outcome, as defined in the registry: Number of crowns evaluated within each group after 1 year in vivo
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: 77 patients enrolled in study- Each patient received a maximum of two crowns. Consequently, the total # of participants is less than the sum of participants in each group. If more than one crown placed, crowns may have been distributed as one from each group or two of the same group.
| Characteristic | Unit | DVS Veneer | Conventional Veneer | Total |
|---|---|---|---|---|
| Participants analysed | 45 | 43 | 77 | |
| Age, Categorical: <=18 years | Crowns | 0 | 0 | 0 |
| Age, Categorical: Between 18 and 65 years | Crowns | 44 | 46 | 90 |
| Age, Categorical: >=65 years | Crowns | 6 | 4 | 10 |
| Sex: Female, Male: Female | Crowns | 38 | 33 | 71 |
| Sex: Female, Male: Male | Crowns | 12 | 17 | 29 |
| Race and Ethnicity Not Collected | Participants | — | — | 0 |
6. Primary Endpoint
The registry lists the primary outcome as Clinical Performance of Crowns Via Modified United States Public Health Service (USPHS) Criteria, measured over 1 year.
| Element | Registry entry |
|---|---|
| Result type | Count Of Units |
| Measure of spread | not applicable |
| Unit | Crowns |
| Endpoint classification | not reduced to a single comparison |
The primary endpoint is clinical performance of crowns assessed by modified United States Public Health Service criteria. The registry describes performance as the percentage of teeth with perfect alpha/A scores after 1 year. An alpha/A score represents the most favorable category for each listed criterion. The criteria address appearance and fit, surface condition, fracture, contact between neighboring teeth, sensitivity, and caries. The registry record describes distinct rating categories for these features; it does not report the observed percentages for either group.
These criteria are used to describe several aspects of crown performance in a structured way. A perfect-score percentage gives a reader an indication of how often crowns meet the top rating across the assessed criteria, while the categories also allow less favorable findings to be distinguished. However, a percentage of perfect scores does not by itself show the distribution of every rating, the reason for any non-perfect rating, or how different clinical features contributed to the result.
The outcome unit is crowns, and the stated population is crowns evaluated within each group after 1 year in vivo. Although the registry lists 1 year as the timeframe, the actual endpoint values and the handling of crowns not evaluated at that time are not reported in the registry record. Without those results, the endpoint definition can be described, but the size, direction, and precision of any difference between groups cannot be assessed.
7. Why No Re-analysis Is Shown
8. Statistical Interpretation
The registry identifies a randomized comparison of two veneer fabrication approaches, but it does not report the primary outcome values. Therefore, the posted record does not establish which group had a higher proportion of crowns with perfect alpha/A scores, how large any difference was, or how uncertain an estimate might be. No conclusion about comparative clinical performance can be drawn from the endpoint description alone.
The primary outcome is expressed as the percentage of teeth with perfect ratings under modified USPHS criteria at 1 year. It includes multiple clinical domains rather than a single narrowly defined event. A perfect-score summary can be useful, but interpretation depends on the scoring and aggregation rules: whether a crown must receive an alpha/A rating on every listed criterion to count as perfect, how each domain is summarized, and how missing assessments are treated. The registry record does not report those details beyond its general description of the endpoint.
The record states that the primary outcome has several categories or time points and is not reduced to one comparison. This means there is no single primary effect estimate in the record for interpretation. The listed outcome domains may capture different aspects of crown performance, and results for one domain would not automatically describe the others. Because the domain-level results are not reported in the registry record, their separate patterns cannot be assessed either.
Random allocation is relevant because, when implemented appropriately, it can help make treatment groups comparable with respect to factors that might otherwise influence outcomes. The registry does not report the sequence-generation or concealment procedures, and it lists no masking. The implications of these design features for outcome assessment cannot be fully evaluated from the available record. In general, knowledge of assigned treatment can matter when outcomes involve clinical ratings, but the record does not describe who assessed the crowns or what safeguards were used.
There are 2 outcome measures and 7 analyses listed, but the record does not explain how those analyses relate to one another, which were prespecified, or whether any multiplicity adjustment was used. It also does not report confidence intervals, p-values, or other uncertainty measures for the primary outcome. A confidence interval, as a general statistical concept, describes a range of values compatible with an estimate under the method’s assumptions; without an estimate and its uncertainty, the precision of the comparison cannot be evaluated.
The study status is terminated, but the reason and its consequences are not reported in the registry record. Termination alone does not indicate the direction or validity of the findings. It does, however, make the lack of documented outcome values and analysis details especially important when deciding what the registry record can support. The responsible interpretation is limited to the design and endpoint descriptions that are actually recorded.
9. Statistical Methods Explained
What does the endpoint describe?
The primary endpoint is a count-based clinical outcome expressed as the percentage of teeth with perfect alpha/A scores under modified USPHS criteria after 1 year. The listed criteria cover color match, margin adaptation, margin discoloration, surface finish, crown fracture, proximal contact, sensitivity, and caries. Each has categories describing different levels of clinical rating. The record does not say how these separate ratings were combined into a crown-level perfect score, beyond its summary description, and it does not provide the actual endpoint values.
In general, a proportion or percentage describes how frequently an outcome occurs among the units assessed. Here the unit is crowns, not necessarily participants. The registry record says the outcome population is the number of crowns evaluated within each group after 1 year in vivo. It does not report the number of crowns with perfect scores, the denominator used for each specific criterion, or how missing assessments were handled. Those details are needed to reproduce or fully interpret the reported percentage.
What can randomization contribute?
In general, random allocation is intended to reduce systematic differences between groups at the point of assignment. It does not guarantee that groups will be alike in every respect, particularly in a study of limited size, and it cannot by itself prevent differences in follow-up, assessment, or analysis. This record labels allocation randomized, but it does not describe sequence generation, allocation concealment, or the methods used to implement assignment.
The record lists masking as none. General statistical interpretation of an unmasked study depends in part on which people knew the assigned treatment and whether that knowledge could affect treatment delivery, assessment, or follow-up. The record does not report who performed the clinical ratings or whether assessments were standardized beyond the modified USPHS criteria. It is therefore not possible to characterize the practical effect of the absence of masking from the registry description alone.
How should group comparisons be interpreted?
A group comparison would ordinarily summarize the endpoint in each arm and quantify the contrast between them. For a percentage outcome, the interpretation depends on the definition of the numerator and denominator, the handling of multiple crowns per participant, and the method used to account for uncertainty. The posted record does not contain the primary group values or a single comparison. It also does not report a model, a test, a confidence interval, or a p-value for that comparison.
As a general concept, a confidence interval conveys uncertainty around an estimated effect, conditional on the statistical method and its assumptions. A point estimate alone does not show how precisely an effect is known; an interval can help distinguish a relatively precise estimate from one compatible with a broad range of effects. No such estimate or interval for the primary endpoint is reported in the registry record. No claim about statistical significance or precision can therefore be made from the endpoint description.
What do the analysis counts tell the reader?
The record lists 2 outcome measures and 7 analyses. These counts indicate that multiple outcomes or analyses are registered, but they do not identify the complete analysis plan or establish which analyses were primary, secondary, exploratory, or prespecified. The record explicitly indicates that the primary outcome has several categories or time points and is not reduced to one comparison. Without a defined single contrast and its results, readers cannot treat the listed criteria as a unified statistical finding.
When many outcomes, criteria, time points, or analyses are examined, the chance of finding an apparently unusual result can increase if the analyses are treated as independent opportunities for a positive finding. General approaches to this issue include prespecifying a primary comparison, adjusting inference for multiple testing, or clearly identifying analyses as exploratory. Which approach, if any, was used is not reported in the registry record. No adjustment should be assumed.
What do the planning assumptions mean?
The record describes planning illustrations based on the observed effect, with a two-sided significance level of 0.05, equal allocation between arms, and a normal approximation. It says the effect to detect is a stated fraction of the observed effect. Such illustrations are planning calculations, not evidence about how many participants were actually enrolled or how likely the study was to detect an effect after completion. The calculation results are not specified in the record summarized by these registry entries, and the registry does not report the trial’s own sample-size justification.
In general, a sample-size calculation depends on an assumed effect, variability or event frequency, error tolerance, allocation, and analysis method. If those assumptions differ from the eventual data or planned analysis, the planning result may not reflect the study’s actual precision. A sample-size illustration based on an observed effect is not observed power and should not be interpreted as a result of the trial. The registry record does not report the assumptions used in the original design beyond the planning illustration description.
Why can over-dispersion matter in general?
For count outcomes, simple statistical models may assume that the variability follows a particular relationship to the average count. Over-dispersion means the observed variability is greater than that assumption allows. In general, ignoring it can make uncertainty estimates too small and tests too optimistic. This is a general consideration for count data, not a claim that over-dispersion occurred in this study. The registry record does not report a count model or any assessment of dispersion, and the primary endpoint is described as a percentage of crowns receiving perfect scores rather than as a detailed count analysis.
10. Multiplicity, Missing Data and Analysis Populations
The record lists 2 outcome measures and 7 analyses, while also noting that the primary outcome has several categories or time points and is not reduced to one comparison. It does not identify a single reported primary contrast across those categories. The record does not state whether the criteria were analyzed separately, how a perfect score was defined across them, or which analysis was designated as the main test of the study question.
When several outcomes or analyses are considered, multiplicity is a general statistical concern: without a prespecified strategy, the interpretation of isolated results can be misleading. Possible strategies include defining a primary outcome and contrast in advance, adjusting for multiple comparisons, or treating additional analyses as exploratory. The registry record does not report whether any such strategy was specified or applied. It is not appropriate to assume either that multiplicity was controlled or that it was ignored.
Missing-data methods and analysis populations are also not reported in the registry record. The endpoint is defined for crowns evaluated after 1 year, but the record does not state how many were assessed, how incomplete assessments were handled, or whether the analysis included all randomized participants, all available crowns, or another population. It does not describe imputation, exclusions, or sensitivity analyses. These details matter because the analyzed crowns may not represent all crowns originally assigned if follow-up is incomplete. The record’s terminated status does not explain whether missingness occurred or how any such issue was addressed.
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 |
|---|---|---|---|
| DVS Veneer | 0 | 45 | 0.0% |
| Conventional Veneer | 0 | 43 | 0.0% |
Other (non-serious) adverse events
Participants with at least one non-serious event at or above the registry's 0% reporting threshold.
| Arm | Participants affected of at risk |
|---|---|
| DVS Veneer | 0 of 45 |
| Conventional Veneer | 0 of 43 |
The adverse-event figures list 0 serious events and 0 other events for the DVS Veneer group among 45 at risk, and 0 serious events and 0 other events for the Conventional Veneer group among 43 at risk. No top serious-event terms are listed. Death counts are not reported in the registry record.
These figures describe what was recorded in the registry; they do not, on their own, establish that no events occurred outside the recorded definitions, reporting period, or data collection process. The registry record does not describe event-collection procedures, follow-up completeness, or the period covered by the safety counts. The at-risk figures are reported for the groups, while the study enrollment is 77 participants and the primary outcome unit is crowns. How the adverse-event denominators relate to enrollment and the endpoint populations is not reported in the registry record.
Zero recorded events should therefore be read narrowly as zero events in the posted categories and groups, not as proof that the devices carry no risk. The record does not provide detail about how events were defined, reviewed, or attributed.
12. What the Result Does, and Does Not, Mean
The registry record establishes that the study compared a CAD/CAM-made DVS veneer with a laboratory-technician-made Conventional Veneer on similar CAD/CAM Lava crowns. It identifies randomized allocation, no masking, a parallel-group design, and a clinical endpoint assessed at 1 year using modified USPHS criteria. These details define the broad question and the type of outcome the study intended to assess.
The record does not report the primary endpoint values, a single group comparison, or uncertainty estimates. It therefore does not show whether the groups differed, the direction of any observed difference, or the precision of an estimate. The endpoint description alone cannot establish that either veneer approach had better clinical performance. It also cannot support conclusions about outcomes beyond the specified criteria and assessment timeframe.
A perfect-score percentage is only one possible summary of a multidomain clinical assessment. Without domain-level findings and the rule for combining scores, the summary cannot show which feature drove any result or whether a particular rating category was more common. The registry record does not report these details. Likewise, the listed counts of outcomes and analyses do not establish whether all analyses were planned in advance or whether their findings were adjusted for multiplicity.
The safety figures record no serious or other adverse events in the listed groups, but the record does not describe how safety information was collected or how complete reporting was. Those figures should be interpreted as registry entries, not as a guarantee that no harm occurred. The terminated status is recorded, but its reason and any effect on study completion or interpretation are not reported.
In general, a clinical study result is most informative when the outcome definition, analysis population, group estimates, and uncertainty are all available. Here, the registry record supports description of the design, endpoint, and posted safety counts, but not a conclusion about comparative effectiveness or the reliability of an unreported treatment effect.
13. Why This Trial Matters Statistically
This trial is statistically relevant because its primary endpoint is not a single binary clinical event with a simple interpretation. It involves multiple rating criteria describing distinct features of crowns, then summarizes performance as the percentage of teeth with perfect alpha/A scores. Such an endpoint raises practical questions about how scores are combined, what denominator is used, and how incomplete assessments are treated. The registry record does not report those operational details or the outcome values.
The study also illustrates why the unit of analysis matters. Enrollment is reported as 77, while the primary outcome is described in crowns and the safety groups have separate at-risk counts. Participant-level and crown-level quantities are not necessarily interchangeable. The record does not explain the relationship between participants and crowns or how multiple crowns from a participant, if present, were accounted for statistically.
Randomization is an important design feature, but it does not replace reporting of the analysis. Readers also need to know how assignment was implemented, who assessed outcomes, which comparisons were prespecified, and how missing observations were handled. The registry record gives limited design labels but does not report those details. The lack of masking is particularly relevant to evaluating clinical ratings, while the assessor procedures are not documented.
Finally, the record lists multiple outcome measures and analyses but does not provide a single primary comparison or a multiplicity strategy. This limits the ability to interpret an isolated result even if one were available. The record is a useful example of the distinction between a defined clinical endpoint and a statistically interpretable estimate: the endpoint framework is described, but the result and its precision are not reported.
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.
Several trial-specific limitations are apparent from the registry information. The study is marked terminated, but the reason for termination and its impact on enrollment, follow-up, or planned analyses are not reported in the registry record. The recorded primary completion is 2014-03, yet the record does not explain the status of each outcome or whether the registered analyses were completed.
The primary endpoint has multiple clinical criteria, but the record does not give a single comparison or the group-level percentages. It also does not report criterion-specific results, a score-combination rule, confidence intervals, or p-values. This prevents assessment of both the direction and precision of the primary outcome. The number of crowns evaluated in each group after 1 year is not stated in the endpoint results, and missing-data handling is not reported.
The record lists randomized allocation but does not describe sequence generation or concealment. Masking is listed as none, while assessor identity and rating procedures are not reported. The analysis populations, model, sample-size justification, and multiplicity approach are also not reported in the registry record. The record’s planning-illustration description is not a substitute for the original design justification or observed outcome estimates.
Enrollment is reported in participants, whereas the primary outcome is measured in crowns and adverse-event figures use group-specific at-risk counts. The relationship among these quantities is not reported. The safety entries also lack details about ascertainment and follow-up. These documentation limits mean that the available record supports only a restricted account of study design, endpoint definition, and recorded event counts.
15. Related Tutorials
16. Related Statistical Calculators
17. Sources
- ClinicalTrials.gov: Clinical Evaluation of Lava Digital Veneer System (DVS) Crowns — NCT01278862.
- Registry record last updated 2024-12-02; status last verified 2024-11.
- Results first posted 2018-12-26.
- 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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18. Record Summary
NCT01278862, titled Clinical Evaluation of Lava Digital Veneer System (DVS) Crowns, was a randomized, unmasked, parallel-group device study. It compared a CAD/CAM-made DVS veneer with a laboratory-technician-made Conventional Veneer on similar CAD/CAM Lava crowns. Enrollment was 77, and the record is marked terminated.
The primary outcome was clinical performance assessed with modified USPHS criteria, expressed as the percentage of teeth with perfect alpha/A scores after 1 year. The criteria address multiple aspects of crown condition and function. The record lists 2 outcome measures and 7 analyses but does not reduce the primary outcome to one comparison. Primary outcome values and uncertainty estimates are not reported in the registry record.
The posted safety counts list 0 serious and 0 other events in each group; deaths are not reported. The reason for termination, detailed analysis methods, missing-data handling, and multiplicity strategy are not reported in the registry record.