A Study to Evaluate the Effectiveness of Laser-Ablated Implant-Abutments to Promote Tissue Healing: Complete Statistical Analysis

1. Trial at a Glance

This page covers the registry results for A Study to Evaluate the Effectiveness of Laser-Ablated Implant-Abutments to Promote Tissue Healing (NCT01822223), a randomized na study. The primary outcome is Number od Participants With Consistent Connective Tissue Integration at a Histologic Level.

2. Clinical Question

3. Trial Design

This was a randomized, double-blind, parallel-arm clinical trial of two dental implant-abutment designs. One arm received laser-ablated dental implant-abutments and the other received smooth implant-abutments; both were described as being attached to surgically placed dental implants. The registry lists an enrollment of 20 and reports 10.0 participants in each arm for the primary outcome. The study status is completed.

The trial record gives a start date of 2010-11 and a primary completion date of 2014-08. The phase is recorded as NA. The sponsor is the University of Alabama at Birmingham. The condition is listed as Jaw, Edentulous, Partially. Additional information about recruitment locations, eligibility criteria, participant characteristics, or the treatment and follow-up procedures is not reported in the registry record.

The stated purpose was to determine which abutment design is more likely to promote early soft-tissue healing processes and/or enhance longitudinal peri-implant bone and soft-tissue health. The primary outcome addresses connective tissue integration at a histologic level at 8 weeks post-abutment placement. The record describes assessment using radio graphic images of tissue and bone around the implant; it does not explain how those images were used to classify histologic integration.

Random allocation can help balance participant characteristics across arms on average, while masking is intended to limit the influence of expectations on care or outcome assessment. These are general design principles, not evidence about how allocation or masking was implemented in this trial. The allocation sequence, concealment procedures, masking details, and any deviations from the assigned abutment are not reported in the registry record. The record also does not report a sample-size justification or the statistical plan used to analyze the primary outcome.

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

Reasons for not completing this period:

Analysis population for the primary outcome, as defined in the registry: The number of participants entered represents measured data.

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.

6. Primary Endpoint

The registry lists the primary outcome as Number od Participants With Consistent Connective Tissue Integration at a Histologic Level, measured over 8 weeks post-abutment placement.

The primary endpoint is the number of participants with consistent connective tissue integration at a histologic level, assessed at 8 weeks post-abutment placement. The registry describes the assessment as based on radio graphic images of tissue and bone surrounding the implant. The posted outcome is expressed as a participant count for each arm rather than as a continuous measurement. The recorded values are 10.0 for laser-ablated dental implant-abutments and 10.0 for smooth implant-abutments.

This endpoint addresses a biological process relevant to the study’s stated aim of evaluating early soft-tissue healing around an implant-abutment. A count makes the observed outcome in each arm straightforward to describe and supports a comparison of the proportion meeting the endpoint. In general, a binary endpoint reduces each participant’s outcome to whether the defined event was recorded or not; it does not preserve gradations in the extent or quality of healing.

The registry’s description leaves important measurement details unresolved. It does not report the criteria for “consistent” integration, the image-reading process, whether assessors were masked, or how disagreements were handled. It also does not explain the relationship between the histologic wording of the endpoint and the stated use of radio graphic images. These details matter when judging what the count represents. Further information on the endpoint’s operational definition is not reported in the registry record.

7. Results Posted in the Registry

• Smooth Implant-abutments: 100.0% (10/10) versus 100.0% (10/10) on control; risk difference 0.0 percentage points (95% CI 0.0 to 0.0), risk ratio 1.00 (1.00–1.00); unadjusted two-proportion z-test p = n/a.

8. Statistical Interpretation

9. Statistical Methods Explained

What does a binary endpoint represent?

In general, a binary endpoint records whether a defined event occurred for each participant. Here, the registry labels the primary outcome as a number of participants and describes the event as consistent connective tissue integration at a histologic level. A count can be informative, but interpretation depends on a clear rule for classifying participants as having or not having the event. The registry description mentions radio graphic images but does not report the classification criteria, reader procedures, or handling of uncertain assessments. These measurement details are not reported in the registry record.

For a binary outcome, researchers often summarize each arm using the number with the event and the number assessed. A risk is the event count relative to the group assessed. The record lists the event count and arm size as 10.0 in both arms. The posted comparison presents a risk difference and a relative risk. The registry entries do not identify a more detailed analysis method, and none should be inferred from the labels alone.

How should the risk difference be read?

In general, a risk difference subtracts the event risk in one group from the event risk in the other group. A value of 0.0 indicates that the estimated risks are the same on the scale of absolute difference. The registry reports a risk difference of 0.0 for the smooth-abutment comparison with the laser-ablated arm as the control, and reports limits of 0.0 and 0.0. This is consistent with the equal posted event counts and arm sizes. It describes the observed comparison; it does not by itself demonstrate equivalence or rule out a difference in the populations from which the participants came.

How should the relative risk be read?

In general, a relative risk compares the event risk in one group with the event risk in another. A value of 1.0 represents equal estimated risks. The registry lists a relative risk of 1.0 and limits of 1.0 and 1.0. Because the event was recorded for every participant in the posted counts, this relative measure offers the same descriptive message as the risk difference: the observed event frequency is identical in the two arms. The interval limits are also identical to the point estimate, but the calculation method and confidence level are not reported in the registry record.

Absolute and relative measures answer different questions in general. The risk difference describes the size of a contrast in percentage-point terms, while a relative risk expresses one group’s event frequency relative to the other. No percentage-point conversion is needed to read the reported risk difference here, and none is added. In settings where event counts are sparse or absent, some relative measures can be undefined or require special methods; that general concern does not establish how this record’s estimates were calculated.

What does an interval normally convey?

In general, a confidence interval describes a range of values compatible with an estimate under a specified statistical procedure. It reflects sampling uncertainty under that procedure; it is not a guarantee that the true value lies inside the interval, and it does not account automatically for bias, measurement error, or limitations in trial conduct. The registry displays limits for both the risk difference and relative risk, but does not report the confidence level or interval method. The reported limits coincide with their point estimates. Without the method and confidence level, the apparent zero width cannot be interpreted as evidence of perfect precision.

What analysis details are available?

The record contains a primary comparison but lists no analysis entries. It does not report a statistical test, regression model, adjustment variables, treatment of repeated or clustered measurements, or a prespecified analysis population. It also does not report how missing outcome data, protocol deviations, or participants without an assessable image were handled. These omissions do not show that such methods were absent from the trial; they mean they are not reported in the registry record.

Randomization and masking are listed as design features. In general, randomization supports a comparison by allocating participants without choosing treatment based on their known characteristics. Masking can reduce the influence of knowledge of assigned treatment on measurement or decisions. The registry does not describe sequence generation, concealment, who was masked, or whether masking was maintained. The design labels alone cannot establish those implementation details.

How should planning calculations be understood?

In general, sample-size calculations depend on assumptions about the effect worth detecting, variability or event frequency, significance level, power, and allocation. The planning illustration described for this trial uses a two-sided significance level of 0.05, equal allocation, a normal approximation, and an effect expressed as a fraction of the observed effect. Such calculations are planning illustrations, not observed power and not evidence about the probability that the study has detected an effect.

The posted primary comparison has an observed risk difference of 0.0. A planning exercise tied to a fraction of an observed effect must therefore be interpreted cautiously: it is not an independent clinical target or a substitute for a prespecified effect considered meaningful. The registry’s own sample-size justification and design assumptions are not reported in the registry record. No additional sample-size values or conclusions about feasibility can be inferred from the assumptions alone.

10. Confidence Intervals and Precision

Precision concerns how much uncertainty surrounds an estimated comparison. The registry reports a risk difference of 0.0, with limits of 0.0 and 0.0, and a relative risk of 1.0, with limits of 1.0 and 1.0. The point estimates match the equal counts recorded in the two arms. Taken literally, the reported intervals have no width, but the registry does not state the confidence level or the method used to obtain them.

In general, an interval’s interpretation depends on its statistical construction. A confidence interval is not simply a range of observed outcomes; it is calculated using a procedure with assumptions about the data and sampling. A narrow interval can indicate greater precision when the method is appropriate and its assumptions are reasonable. However, interval width cannot be evaluated fully without knowing the procedure and confidence level. Here, the coincident limits should not be treated as proof that the underlying effect is known exactly.

The arm counts are 10.0 in each group, and the recorded outcome value is 10.0 in each. This uniform pattern is important for precision: the data contain no observed separation between arms for this endpoint, and the result sits at the event ceiling in both arms. In general, such a pattern can make it difficult to learn how outcomes might differ beyond the observed participants. The registry does not report an alternative method or sensitivity analysis that would clarify uncertainty for this pattern.

Other contributors to precision include the way the endpoint was measured, missing observations, and the analysis population. The record does not report enough detail to assess those factors. In particular, it does not state whether the reported arm counts include every randomized participant or only those with an assessable outcome. The reported limits are therefore best read as registry-listed values whose statistical interpretation is incomplete, rather than as a full account of uncertainty.

11. Multiplicity, Missing Data and Analysis Populations

The registry lists one primary outcome and five secondary outcome entries. The secondary entries include grams of force needed to disrupt tissue attachment to the abutment and mean change in clinical attachment in millimeters; the clinical-attachment outcome appears in multiple entries. The record lists six outcome measures overall, but no analysis entries for these outcomes. Secondary outcome results, their analysis populations, and their statistical comparisons are not reported in the registry record.

Multiplicity arises in general when several outcomes, time points, or comparisons are tested. If many hypotheses are assessed, the chance of finding at least one apparently notable result can increase unless the analysis plan accounts for the number and structure of tests. Whether an adjustment was planned or used in this trial is not reported in the registry record. With no posted secondary analyses, the registry results do not permit an assessment of multiplicity handling or selective emphasis across the listed outcomes.

The record does not describe missing-data procedures. It does not state whether any primary-outcome assessments were unavailable, how unavailable or indeterminate measurements were treated, or whether participants were analyzed according to their randomized assignment. The posted counts and values alone do not answer those questions. The analysis population, including whether it was intention-to-treat or another population, is not reported in the registry record.

In general, these details matter because exclusions or missing outcomes can affect the balance created by randomization, and because different approaches to missing data can produce different estimates. This is a general methodological consideration, not a claim that missing data or exclusions occurred in this trial. The record also does not report a statistical analysis plan, prespecified multiplicity strategy, or sensitivity analyses. The primary comparison can be described as posted, but the broader outcome and analysis framework remains unclear.

12. Safety Results

The registry reports serious adverse events as affected participants divided by participants at risk.

Other (non-serious) adverse events

Participants with at least one non-serious event at or above the registry's 1% reporting threshold.

The adverse-event record lists 0 serious events among 10 participants at risk in the laser-ablated arm and 0 among 10 at risk in the smooth-abutment arm. It also lists 0 other adverse events among 10 at risk in each arm. No serious adverse-event terms are listed. These figures describe what is recorded in the registry for the stated groups; they do not establish that no events occurred outside the scope of reporting or observation.

In general, safety counts need to be read alongside their observation period, event definitions, collection procedures, and completeness of reporting. The registry does not report those details for these adverse-event figures. Deaths are not given as a numeric result in the record, so death counts are not reported in the registry record. The absence of a listed serious event should not be interpreted as proof of no risk, especially without information on follow-up duration and event ascertainment.

The trial’s main posted comparison concerns connective tissue integration, not a comprehensive safety evaluation. The adverse-event counts are therefore a limited description of recorded events in the trial arms, rather than a full assessment of all possible harms.

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

The result establishes what the registry records for the primary endpoint: 10.0 participants in each arm had the outcome recorded, and the risk difference is 0.0. The listed relative risk is 1.0. The endpoint was assessed at 8 weeks post-abutment placement, according to the record, and its description refers to radio graphic images of tissue and bone surrounding the implant.

That finding does not establish that the two abutment designs are equivalent. Equivalence requires a prespecified margin and an analysis designed to evaluate whether the difference is sufficiently small; such a margin and analysis are not reported in the registry record. Nor does the result establish that one design is superior, or that either design has no effect. It describes equal observed counts for one recorded endpoint at one stated follow-up.

It also does not resolve the longer-term aims mentioned in the study summary. The stated purpose includes longitudinal peri-implant bone and soft-tissue health, but the registry’s posted primary comparison concerns an outcome at 8 weeks. The listed secondary outcomes include clinical attachment changes and force needed to disrupt tissue attachment, yet their analysis results are not reported in the registry record. The primary result cannot stand in for those unreported outcomes or follow-up periods.

The result does not tell readers how the endpoint was classified, whether image assessors were masked, how missing observations were handled, or which analysis population was used. It also does not provide the confidence level or method for the reported interval. Those omissions limit assessment of measurement validity, risk of bias, and statistical precision. They do not change the fact that the registry reports the same count in both arms, but they constrain the conclusions that can be drawn from it.

In practical terms, the posted data support a narrow descriptive statement: the registered counts for consistent connective tissue integration were equal in the two trial arms. Claims about clinically meaningful differences, longer-term outcomes, or safety beyond the reported adverse-event counts require information that is not reported in the registry record.

14. Why This Trial Matters Statistically

This trial illustrates why a clear endpoint definition and transparent analysis reporting matter in a randomized comparison. The primary outcome is expressed as a count of participants, but its description combines histologic wording with assessment by radio graphic images. The registry does not explain the classification rule or how the image-based assessment corresponds to the endpoint label. Such details are central to understanding what a measured event represents, independent of the numerical comparison.

The posted counts are identical, and both arms are at the event ceiling in the reported data. This creates an opportunity to distinguish the observed result from broader claims: equal outcomes among the listed participants are a descriptive finding, while equivalence or absence of an effect requires an appropriate design and analysis. A reported interval with identical point estimate and limits makes the need for interval-method reporting especially visible. The registry does not identify the method or confidence level.

The record also highlights the difference between listing outcomes and reporting analyses. Five secondary outcome entries appear, but no analysis entries are listed. Without results and analysis details, readers cannot assess whether the study’s broader aims regarding attachment, soft tissue, and peri-implant health were addressed in the posted results.

These features make the trial useful as an example of how registry records can provide a clear design outline and primary outcome counts while leaving important interpretive details unavailable. Careful statistical reading preserves the descriptive finding without turning it into a stronger conclusion than the record supports.

15. 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 of interpretation arise from the information recorded. The registry does not report detailed eligibility criteria or participant characteristics, so it is not possible to judge how closely the enrolled participants represent other people with a partially edentulous jaw. It also does not report recruitment settings or further details about the dental implant procedures.

The primary endpoint’s wording refers to integration at a histologic level, while the description states that assessment used radio graphic images of tissue and bone surrounding the implant. The criteria for a positive result, the image-reading procedure, and assessor masking are not reported in the registry record. This leaves uncertainty about the endpoint’s operational definition and measurement reliability.

The posted result is at the event ceiling in both arms, with equal recorded counts and a risk difference of 0.0. The reported interval limits equal the point estimates, yet the confidence level and interval method are not reported. The analysis method, analysis population, treatment of missing data, and any sensitivity analyses are also not reported in the registry record. These gaps prevent a complete assessment of precision and robustness.

Although secondary outcomes are listed, their analysis results are not reported in the registry record. The record also does not report a sample-size justification or explain whether the primary endpoint and analysis were prespecified in a statistical plan. These limitations do not negate the posted comparison, but they restrict conclusions about endpoint validity, possible bias, broader outcomes, and the extent to which the result applies beyond the recorded trial participants.

16. Related Tutorials

17. Related Statistical Calculators

18. Sources

• ClinicalTrials.gov: A Study to Evaluate the Effectiveness of Laser-Ablated Implant-Abutments to Promote Tissue Healing — NCT01822223.
• Registry record last updated 2017-01-25; status last verified 2016-09.
• Results first posted 2017-01-25.
• 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.

19. Record Summary

The registry describes a completed, randomized, double-blind, parallel-arm trial sponsored by the University of Alabama at Birmingham. It compared laser-ablated dental implant-abutments with smooth implant-abutments, with an enrollment of 20. The recorded start date is 2010-11, and the primary completion date is 2014-08. The condition is listed as Jaw, Edentulous, Partially.

The primary outcome was the number of participants with consistent connective tissue integration at a histologic level at 8 weeks post-abutment placement. The registry describes assessment by radio graphic images. The posted counts are 10.0 in each arm; the reported risk difference is 0.0 and the relative risk is 1.0. Five secondary outcome entries are listed, with no analysis entries. Further information on the analysis method, interval construction, missing data, and outcome assessment procedures is not reported in the registry record.