Prospective, Comparative Assessment of Alveolar Bone Augmentation Using GUIDOR® Membrane in the Bound Edentulous Space: Complete Statistical Analysis

1. Trial at a Glance

This page covers the registry results for Prospective, Comparative Assessment of Alveolar Bone Augmentation Using GUIDOR® Membrane in the Bound Edentulous Space (NCT02387008), a randomized na study. The primary outcome is Dimensional Bone Changes at 6 Months.

2. Clinical Question

3. Trial Design

The registry describes a randomized, double-masked, parallel-group study. It lists three intervention groups: synthetic GUIDOR® membrane with FDBA, synthetic GUIDOR® membrane alone, and xenograft Bio-Gide® membrane with FDBA. The study summary describes a multicenter plan, with 30 patients at each study site, and a planned total of 60 patients. The recorded enrollment is 6. The registry record does not explain the difference between the planned enrollment in the summary and the recorded enrollment.

The study began on 2017-06-30, and the primary completion date is listed as 2018-11-28. Its status is TERMINATED. The reason for termination is not reported in the registry record, so the status alone does not establish why recruitment or follow-up ended.

The primary assessment was planned for 6 months after treatment. CBCT imaging was to be obtained at baseline and 6 months post-operatively to evaluate dimensional changes in the alveolar ridge. Post-operative visits at 1, 2, and 4 weeks were also described, to assess inflammation, infection, wound dehiscence, or membrane exposure. The listed secondary outcomes include inflammation, infection, and membrane exposure.

Randomization is intended to assign participants to treatment groups by chance, which can reduce systematic differences between groups. A parallel design means participants are assigned to a group rather than receiving each intervention in sequence. The registry identifies the study as double-masked, but it does not report which participants, clinicians, assessors, or other personnel were masked, or how masking was maintained. The randomization procedure, allocation concealment, and details about the study sites are not reported in the registry 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

Analysis population for the primary outcome, as defined in the registry: Protocol-defined collection intervals were not achieved for any subjects enrolled; therefore, no data available for this measure.

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: No participants were randomized to the GUIDOR® Membrane Alone Arm

6. Primary Endpoint

The registry lists the primary outcome as Dimensional Bone Changes at 6 Months, measured over 6 months after treatment.

The primary outcome was dimensional bone change 6 months after treatment. The registry describes measuring changes in horizontal width and vertical height from DICOM images acquired by CBCT. These dimensions relate to the study’s stated aim of evaluating alveolar ridge changes after horizontal bone augmentation before dental implant placement.

As a general measurement concept, imaging-based dimensions can describe structural change at a specified follow-up time. Baseline and follow-up images can support an assessment of change over time, but interpretation depends on having the planned images, a defined measurement procedure, and outcome data for the participants being evaluated. The registry record does not report details such as measurement reliability, assessor procedures, or a statistical definition of the primary endpoint beyond the description of horizontal width and vertical height changes.

Most importantly, the registry states that protocol-defined collection intervals were not achieved for any subjects enrolled and that no data are available for this measure. Thus, no observed estimate of bone change, measure of its variability, or comparison among the three interventions is reported. The intended endpoint can be described, but its results cannot be interpreted from the registry record.

7. Why No Re-analysis Is Shown

8. Statistical Interpretation

9. Statistical Methods Explained

What does randomization contribute?

Randomization assigns participants to study groups by chance. As a general statistical principle, this can help balance measured and unmeasured participant characteristics across groups in expectation, reducing the risk that treatment comparisons simply reflect baseline differences. It does not guarantee balance in a small study, and it cannot compensate for missing outcome measurements. The registry identifies the allocation as randomized but does not report the sequence-generation method, allocation concealment, or the number assigned to each group.

What does a parallel-group design mean?

In a parallel design, each participant is assigned to one intervention group and is followed in that group. The registry describes three approaches to bone augmentation: GUIDOR® membrane with FDBA, GUIDOR® membrane alone, and Bio-Gide® membrane with FDBA. A valid group comparison would require outcome data linked to participants’ assigned groups and a prespecified approach to analyzing those data. The registry record does not report an analysis of the primary outcome.

How should double masking be understood?

Masking is intended to limit the influence of knowledge about treatment assignment on study conduct, assessment, or reporting. This is a general explanation; the registry record does not specify which people were masked or how masking was maintained. For an imaging outcome, masking of image assessors may be relevant in general, but whether that was planned or achieved in this study is not reported in the registry record. The masking label alone does not establish the specific safeguards used.

What was the planned outcome assessment?

The primary outcome was dimensional bone change at 6 months after treatment, based on horizontal width and vertical height measurements from CBCT-derived DICOM images. The summary also describes baseline imaging. In general, comparing measurements over time requires a consistent measurement definition and appropriately timed observations. The registry record gives the broad imaging approach and follow-up time, but does not report detailed measurement procedures, assessor agreement, or the statistical model intended for the endpoint.

Why can no treatment comparison be calculated?

A comparative estimate requires observed outcome information for the groups being compared. The registry explicitly states that protocol-defined collection intervals were not achieved for any subjects enrolled and that no data are available for the primary measure. No treatment-effect estimate, standard error, confidence interval, or p-value for this outcome is reported in the registry record. Without such results, a numerical comparison cannot be reconstructed from the posted information. There is also no basis for interpreting a nonsignificant result: no primary-outcome test result is reported.

What do precision and over-dispersion mean in general?

General statistical concepts can help explain what would matter if an outcome estimate were available. A confidence interval expresses uncertainty around an estimate under a particular model and sampling process; narrower intervals generally indicate greater precision, while wider intervals indicate greater uncertainty. Over-dispersion arises when observed variability is greater than a model assumes. In general, ignoring over-dispersion can make uncertainty appear too small. The registry record does not report outcome data or a model for which precision or over-dispersion could be assessed in this trial.

Can the sample-size planning assumptions be interpreted as trial power?

The record describes a planning illustration based on an observed effect, with a two-sided significance level of 0.05, equal allocation between two arms, and a normal approximation. These assumptions describe an illustrative planning calculation, not the trial’s own design or observed power. The primary outcome data needed to establish an observed effect are not available in the registry record, and the study itself has three intervention groups. Any sample-size illustration should therefore not be read as evidence that the study had a particular achieved power or that a treatment effect was detected. The trial’s own sample-size justification is not reported in the registry record.

What statistical analysis is documented?

The registry record does not report a statistical analysis of the primary outcome. It does not report a statistical plan, adjustment variables, a prespecified contrast among the three interventions, or methods for handling repeated measurements. Those details should not be inferred from the study design or from the outcome description. With no reported primary data, the record supports a description of the planned measurement and the missing result, rather than an inferential analysis.

10. Multiplicity, Missing Data and Analysis Populations

The study lists three intervention groups and multiple planned assessments. The primary outcome description includes horizontal width and vertical height changes, and the summary describes imaging at baseline and 6 months. The summary also describes post-operative assessments at 1, 2, and 4 weeks for wound-healing concerns. The listed secondary outcomes are inflammation, infection, and membrane exposure. When a study considers multiple outcomes, time points, or pairwise group comparisons, the chance of a false-positive finding can increase if the analyses are not planned and interpreted carefully. This is a general statistical concern; a multiplicity strategy for this study is not reported in the registry record.

The record does not report which comparisons were intended to be primary, how any multiple testing was to be addressed, or whether any outcome hierarchy was specified. It also does not report a statistical analysis plan. These omissions limit the ability to determine how results would have been selected or interpreted if measurements had been available.

Missing outcome information is especially consequential: the registry states that the protocol-defined collection intervals were not achieved for any enrolled subjects and that no data are available for the primary measure. The record does not report an analysis population, participant-level missingness details, reasons for missing measurements, or methods such as imputation or sensitivity analysis. It is therefore not possible to assess whether missingness was related to treatment, outcome, or other participant characteristics.

In general, an analysis population defines which participants contribute to an analysis, and a missing-data method states how unavailable measurements are handled. Neither is reported for the primary outcome in the registry record. With no reported primary measurements or analysis, multiplicity and missing-data assumptions cannot be evaluated against results.

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 0% reporting threshold.

The registry lists serious adverse event figures separately for the three intervention groups. For GUIDOR® membrane with FDBA, it records 2 at risk and 0 affected; for GUIDOR® membrane alone, it records 0 at risk and 0 affected; for Bio-Gide® membrane with FDBA, it records 4 at risk and 0 affected. The other adverse event figures follow the same pattern: 2 at risk and 0 affected, 0 at risk and 0 affected, and 4 at risk and 0 affected, respectively. Deaths are recorded as 0 in each group, and no top serious terms are listed.

These are the figures recorded for the adverse event entries, not evidence that every enrolled participant was assessed for safety. In particular, the record lists no participants at risk in the GUIDOR® membrane-alone group, so its zero affected figure does not have a reported at-risk denominator. The record does not explain the safety observation period, event definitions, collection procedures, or why the listed at-risk counts differ across groups.

Zero affected in the listed entries means that the registry reports no affected participants within those recorded entries. It should not be generalized to unreported participants or used to establish comparative safety. The study’s terminated status and unavailable primary outcome do not, on their own, explain the adverse event figures.

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

The registry record documents a planned randomized comparison of three bone-augmentation approaches and identifies dimensional bone change at 6 months as the primary outcome. It also reports that protocol-defined collection intervals were not achieved for any enrolled subjects, leaving no primary outcome data. Thus, the posted record does not provide an estimate of bone change or a statistical comparison between the interventions.

This distinction matters: unavailable data are not the same as a measured result showing no change, and they are not evidence that the interventions have the same effect. No conclusion about the direction or magnitude of a difference can be drawn from the primary outcome information. A confidence interval, p-value, or other measure of uncertainty for the primary question is not reported in the registry record.

The posted safety figures describe zero affected participants in the recorded serious and other adverse event entries, with different at-risk counts across groups. Those figures should be interpreted within their recorded denominators and do not establish that all enrolled participants were assessed or that the approaches have equivalent safety. The record does not report enough detail to evaluate the completeness or duration of safety follow-up.

The enrollment recorded as 6 is distinct from the planned total of 60 described in the study summary. The reason for this difference and the reason the study was terminated are not reported in the registry record. Neither should be inferred from the outcome-data statement alone.

In practical statistical terms, the record is informative about the research question and the limits of the available evidence, but it cannot answer the comparative efficacy question. It describes what the investigators intended to measure and reports that those primary measurements are unavailable; it does not establish whether any one approach produced a larger, smaller, or similar change.

13. Why This Trial Matters Statistically

This trial is statistically important because it illustrates the difference between a planned comparison and an analyzable result. Randomization and masking describe design features that can help protect a comparison from bias, but they do not create evidence about treatment effects when the outcome measurements are unavailable. Here, the primary question concerned imaging-based changes in horizontal width and vertical height at 6 months, yet the registry reports no primary outcome data.

The contrast between the recorded enrollment of 6 and the planned total of 60 in the study summary is also relevant to interpretation. It highlights why planned enrollment and actual recorded enrollment should not be treated as interchangeable. The registry does not explain the difference or provide the participant flow needed to understand recruitment, treatment receipt, or follow-up.

The record also shows why adverse event counts require their denominators and context. Counts of zero affected participants may appear reassuring, but their meaning depends on who was observed, for how long, and how events were defined and collected. In this record, the at-risk figures differ by intervention group, including a group with 0 listed at risk.

More broadly, a study record can identify a clinically relevant question without providing a result capable of supporting a statistical conclusion. Readers need to distinguish the intended endpoint from observed data, and observed data from estimates with quantified uncertainty. Because no primary effect estimate or analysis is reported, there is no basis to judge the precision of the intended comparison or to interpret a treatment difference.

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 is that no primary outcome data are reported. The registry states that protocol-defined collection intervals were not achieved for any subjects enrolled. As a result, the planned 6-month assessment of horizontal width and vertical height changes cannot be evaluated from the posted record, and there is no comparative estimate for the three interventions.

The registry records enrollment of 6, while the study summary describes a planned total of 60 and 30 patients at each study site. The reason for the discrepancy is not reported in the registry record. Participant flow by group, treatment received, completion of follow-up, and the number contributing to each outcome are also not reported. This prevents a fuller assessment of recruitment and outcome availability.

The study is listed as TERMINATED, but the reason for termination is not reported in the registry record. The record does not provide the randomization procedure, masking details, endpoint measurement procedures, statistical analysis plan, or analysis populations. It also does not report how missing data or multiple outcomes and comparisons would have been handled.

Safety interpretation is limited by the recorded at-risk counts, which vary across groups, and by the lack of reported details about safety follow-up, event definitions, and collection methods. The zero affected figures therefore cannot establish complete safety ascertainment or support a comparative safety estimate. These limitations concern what can be concluded from the registry record; they do not establish why the study ended or why the outcome collection intervals were not achieved.

15. Related Tutorials

16. Related Statistical Calculators

17. Sources

• ClinicalTrials.gov: Prospective, Comparative Assessment of Alveolar Bone Augmentation Using GUIDOR® Membrane in the Bound Edentulous Space — NCT02387008.
• Registry record last updated 2019-09-25; status last verified 2019-09.
• Results first posted 2019-06-19.
• 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 describes a randomized, double-masked, parallel-group study of horizontal bone augmentation at a bound edentulous site before dental implant placement. The three approaches were GUIDOR® membrane with FDBA, GUIDOR® membrane alone, and Bio-Gide® membrane with FDBA. The primary outcome was dimensional bone change at 6 months, assessed through horizontal width and vertical height measurements using CBCT-derived images.

The record lists enrollment of 6 and status TERMINATED. Its summary describes a planned total of 60 participants. The primary outcome section states that protocol-defined collection intervals were not achieved for any enrolled subjects and that no data are available for the measure. No primary treatment-effect estimate or statistical analysis is reported. The record also lists adverse event counts with differing at-risk figures across groups. The reason for termination, the enrollment difference, and further details about outcome and safety analyses are not reported in the registry record.