A Study Evaluating OsseoSpeed TX Using Different Drilling Protocols With Immediate Loading: Complete Statistical Analysis

1. Trial at a Glance

This page covers the registry results for A Study Evaluating OsseoSpeed TX Using Different Drilling Protocols With Immediate Loading (NCT01340170), a non-randomized na study. The primary outcome is Marginal Bone Level Change.

2. Clinical Question

The study was initiated to support the implant with clinical data on whether the soft bone drilling protocol and immediate loading have an important negative effect on marginal bone level maintenance. That statement describes the study’s motivation, not a finding. The primary endpoint is a radiographic measurement, and the posted registry information identifies its intended measurement interval and unit. However, the registry record does not report the mean changes, their standard deviations, a confidence interval, or a statistical test for the comparison. It therefore does not establish how the groups’ observed outcomes compared, nor how precisely any comparison was estimated. The non-randomized allocation also means that the comparison must be interpreted in light of the different bone-quality categories described for the protocols.

3. Trial Design

This was an open, prospective, multicentre study, with non-randomized allocation and a parallel-group model. Masking is listed as none, and phase is listed as NA. The registry records enrollment of 168. The study is marked completed; its recorded start is 2011-04 and its primary completion is 2014-12.

The intervention is the OsseoSpeed TX device. The registry describes a soft bone drilling protocol for bone quality 3 and 4, and a standard drilling protocol for bone quality 1 and 2. Because protocol and bone-quality category are linked in these descriptions, the groups are not a like-for-like control comparison. In particular, a difference in outcome could reflect differences associated with bone quality as well as differences associated with protocol. The registry record does not report an adjustment strategy that would address this issue.

The primary endpoint is marginal bone level change, expressed in mm, from implant insertion to 12 months post implant insertion. The registry describes radiographic measurement and analysis at implant level. It also lists secondary outcomes concerning implant survival, clinical and manual stability, resonance frequency analysis, and perceptions during implant insertion.

The registry record does not report a detailed statistical analysis plan, a sample-size justification, or an account of interim analyses. It lists 0 analyses. That registry entry does not establish whether analyses were conducted outside the registry; it means that analysis details are not reported in the registry record. Numerical primary outcome results are also not reported there, limiting interpretation of the study’s central comparison.

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: ITT subjects with MBL data available (MBL data missing for 14 implants in Group A, and from 10 implants in group B). Outcome measure 1 is analyzed on implant level only and does not contain subject level group "Group A + B".

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: Intention to treat population

6. Primary Endpoint

The registry lists the primary outcome as Marginal Bone Level Change, measured over Implant insertion and 12 months post implant insertion.

Marginal bone level change is the primary endpoint. The registry describes determining alterations from radiographs as the difference between a reference point on the implant and the most coronal bone-to-implant contact on the mesial and distal aspects. The measurement is expressed in mm, with observations planned from implant insertion to 12 months post implant insertion.

This endpoint is used to describe changes in the bone level around the implant over the specified interval. A continuous measure can retain information about the size of observed changes rather than reducing results to categories. The registry specifies a mean and standard deviation as the summary form. In general, the mean describes the central value of the observations, while the standard deviation describes their spread around that mean. These summaries do not by themselves show the uncertainty in a between-group comparison.

The endpoint is analyzed at implant level. The registry describes the population as ITT subjects with marginal bone level data available, and notes that data are missing for 14 implants in Group A and 10 implants in Group B. It also states that this outcome does not contain a subject-level Group A + B result. The numerical mean changes and their standard deviations are not reported in the registry record, so the magnitude and precision of the endpoint results cannot be assessed from it.

7. Why No Re-analysis Is Shown

8. Statistical Interpretation

9. Statistical Methods Explained

The primary endpoint is a continuous measure summarized as a mean with a standard deviation. In general, a mean provides a compact description of the average observed change, while a standard deviation indicates how dispersed individual measurements are around that average. Neither summary, on its own, quantifies how uncertain an estimated group difference is. A confidence interval is a way to express that uncertainty: it gives a range of values compatible with the data and the analysis method, under the interval’s assumptions. The registry record does not report endpoint means, standard deviations, or a confidence interval.

What does the endpoint represent?

The registry defines marginal bone level alterations using radiographs and a reference point on the implant relative to the most coronal bone-to-implant contact on the mesial and distal aspects. The measurement interval runs from implant insertion to 12 months post implant insertion. As a change measure, it describes the difference across that interval; interpretation depends on the measurement convention and on how the underlying radiographic observations were obtained. The record describes the measurement but does not report numerical results or further details about measurement reliability.

What does non-randomized allocation imply?

In general, random allocation helps make groups comparable, on average, with respect to measured and unmeasured characteristics at baseline. This study is listed as non-randomized. Its arm descriptions tie the soft bone protocol to bone quality 3 and 4, and the standard protocol to bone quality 1 and 2. This makes bone quality an important consideration in interpreting a contrast between groups. If groups differ in prognosis or other relevant characteristics, an observed difference may reflect those characteristics, the protocol, or both. Statistical adjustment can sometimes address measured differences, but it cannot guarantee removal of confounding, especially from unmeasured factors. The registry record does not report whether an adjusted model was used or which covariates it included.

Why does the analysis unit matter?

The primary outcome is described as analyzed at implant level, while its population is described as ITT subjects with available marginal bone level data. These are different concepts: the population description refers to subjects, while the measured outcome and analysis unit refer to implants. If observations are related within a subject, treating them as independent can make uncertainty appear smaller than it is. Appropriate methods can account for clustering or dependence when that structure is present. The registry record does not report whether there were multiple implants per subject or whether any dependence structure was modeled, so the adequacy of the uncertainty calculation cannot be assessed.

How should confidence intervals and tests be read?

In general, a confidence interval communicates the range of effect sizes compatible with the data under the analysis assumptions. A narrow interval indicates greater precision than a wide interval, but neither width nor location can be inferred without the actual estimate and interval. A p-value, when reported, describes how unusual the data would be under a specified null hypothesis and statistical model; it is not the probability that the null hypothesis is true and does not measure clinical importance. The registry record reports no primary endpoint confidence interval or p-value, so neither statistical significance nor precision can be evaluated.

What do the planning assumptions mean?

The planning illustration is described as using a two-sided significance level of 0.05, equal allocation between the two arms, a normal approximation, and an effect specified as a fraction of the observed effect. These assumptions define a hypothetical planning calculation; they do not establish that the trial was designed that way. The record explicitly distinguishes this illustration from the trial’s own design. It is not observed power. In general, power calculations describe the chance of detecting an effect of a specified size under assumptions, and the resulting sample size depends on those assumptions. A calculation based on an observed effect is especially dependent on that effect estimate, which can be unstable. The registry record does not report the endpoint estimates needed to assess the effect underlying the illustration.

Time-to-event planning calculations are described as reporting total events, while other calculations report participants per arm. This is a distinction in the planning convention, not an observed trial result. The registry record does not report a time-to-event analysis for the primary endpoint. More broadly, no detailed statistical plan, interim analysis information, or primary endpoint model is reported in the registry record. These omissions prevent a full assessment of model choice, assumptions, handling of missing data, and the interpretation intended by the investigators.

10. Confidence Intervals for Each Arm

No two-arm comparison is shown for this trial, but each arm's mean can be given with a t-based 95% confidence interval computed from the posted mean, spread and number of participants.

R code and output

arm <- c("Standard Drilling Protocol (Group A)", "Soft Bone Drilling Protocol (Group B)")
n   <- c(63, 72)
m   <- c(-0.25, -0.2)
sp  <- c(0.9, 0.67)
sd  <- sp      # posted standard deviations
for (i in seq_along(n)) {
  se <- sd[i] / sqrt(n[i]); h <- qt(0.975, n[i] - 1) * se
  cat(sprintf("CARM|%s|%d|%.3f|%.3f|%.3f|%.3f\n", arm[i], n[i], m[i], sd[i], m[i] - h, m[i] + h))
}

CARM  Standard Drilling Protocol (Group A)  63  -0.250  0.900  -0.477  -0.023
CARM  Soft Bone Drilling Protocol (Group B)  72  -0.200  0.670  -0.357  -0.043

11. Multiplicity, Missing Data and Analysis Populations

The registry lists 8 outcome measures, including marginal bone level change and secondary measures concerning implant survival, implant stability, and perceptions during insertion. When a study evaluates multiple outcomes or makes multiple comparisons, the chance of at least one apparently notable result can increase. In general, a multiplicity strategy may define a primary comparison, adjust inference across a family of tests, or describe results as exploratory. The registry record does not report a multiplicity strategy, testing hierarchy, or adjustment method. Because numerical results and tests are not reported, the effect of multiplicity on any conclusions cannot be assessed.

Missing primary endpoint data are explicitly noted: marginal bone level data are missing for 14 implants in Group A and 10 implants in Group B. The endpoint population is described as ITT subjects with marginal bone level data available, but the outcome is analyzed at implant level. The registry does not report why these data are missing, whether the reasons differed between groups, or whether missingness was addressed by imputation, weighting, or another method. In general, results based only on available measurements can be biased if the likelihood of having a measurement is related to the outcome or to factors associated with it. The record does not provide enough information to evaluate that possibility.

The ITT description should not be read as proof that missing endpoint observations were included in the endpoint analysis. The record says the measure used subjects with data available and separately notes missing implant-level measurements. It also states that this endpoint does not contain a subject-level Group A + B result. The registry record does not further explain the relationship between subject-level population wording and implant-level analysis, or report sensitivity analyses for missing data.

12. Safety Results

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

Deaths

Other (non-serious) adverse events

Participants with at least one non-serious event at or above the registry's 5% reporting threshold.

The registry reports serious adverse event counts, other adverse event counts, and deaths separately for the listed groups. For Standard Drilling Protocol (Group A), the serious-event count is 0 among 79 at risk, the other-event count is 0 among 79 at risk, and deaths are 0. For Soft Bone Drilling Protocol (Group B), the corresponding counts are 0 among 86 at risk, 0 among 86 at risk, and 0 deaths. For Group A + B, the record lists 0 serious events among 3 at risk, 0 other events among 3 at risk, and 0 deaths.

These entries describe the registry’s reported counts in the categories shown; they do not establish that no adverse events of any kind occurred. The record does not list serious adverse event terms, and it does not provide further detail about event definitions, observation duration, completeness of reporting, or the unusual Group A + B at-risk entry. The figures should therefore be read as the recorded counts for the stated categories, not as a complete characterization of safety or as a comparative safety analysis. The registry record does not report statistical comparisons of adverse events between protocols.

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

The registry record establishes that this was a prospective, open, non-randomized, multicentre study of OsseoSpeed TX implants with immediate loading and two drilling protocols. It identifies marginal bone level change from implant insertion to 12 months post implant insertion as the primary endpoint and describes how that measure was defined. It also records that the protocol groups corresponded to different bone-quality categories.

The registry record does not report numerical results for the primary endpoint. It therefore does not show the observed mean change in either group, the size or direction of a between-group contrast, or the uncertainty around any contrast. It cannot support a conclusion that one protocol had better or worse marginal bone level outcomes, or that the protocols were equivalent. The study’s stated aim and rationale should not be mistaken for evidence that the aim was achieved.

Even if a contrast were reported elsewhere, the non-randomized allocation would require careful interpretation. Bone quality is linked to protocol assignment in the arm descriptions, and the registry record does not report an adjustment strategy. Any comparison could be affected by differences between groups apart from the drilling protocol. The record also notes missing marginal bone level data for implants in both groups, without reporting why the measurements are missing or how missingness was handled.

Planning illustrations based on an observed effect are not a substitute for outcome estimates, and they are not observed power. The registry record does not report the primary endpoint values needed to assess the effect behind those illustrations. Overall, the record describes the study question, design, endpoint, and selected safety counts, but it does not provide the numerical primary outcome results needed to judge the central comparison.

14. Why This Trial Matters Statistically

This trial is statistically notable because the clinical question is framed as a comparison of drilling protocols, while allocation is non-randomized and the registry ties protocol choice to bone quality. That creates a central interpretation issue: a group contrast cannot automatically be attributed to the protocol when the groups are defined by different bone-quality categories. This is a design limitation, not a problem that can be resolved simply by stating the endpoint more clearly.

The primary measure is continuous and collected at implant level, but the registry describes the population in subject-level ITT terms. Keeping the measurement unit and analysis population distinct matters because the validity of standard errors and confidence intervals depends on how observations are structured. If measurements are related within subjects, methods may need to account for that relationship. The registry record does not provide the analysis details needed to determine how this was addressed.

The record also illustrates the distinction between a study rationale and an empirical result. It states an intention to support the implant with data on marginal bone level maintenance, but it does not report numerical estimates for the primary endpoint. Without those results, statistical precision and the magnitude of any group difference remain unknown. A planning illustration based on an observed effect cannot fill that gap.

Finally, the record identifies missing endpoint measurements and multiple outcome measures but does not describe a missing-data strategy or multiplicity plan. Those details affect how confidently findings can be interpreted when results are available. The registry therefore offers useful information about design and measurement, while leaving important elements of the statistical evidence unreported.

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.

The most direct limitation for interpreting the primary question is that numerical marginal bone level results are not reported in the registry record. Means, standard deviations, a between-group estimate, confidence intervals, and a primary endpoint test are absent. The magnitude, direction, and precision of the primary comparison therefore cannot be evaluated from the registry information.

Allocation is non-randomized. The arm descriptions link the soft bone drilling protocol to bone quality 3 and 4 and the standard protocol to bone quality 1 and 2. This makes the groups unlike a randomized comparison and raises the possibility that outcome differences could reflect bone quality or other group differences. The registry record does not report an adjusted analysis that could be examined in relation to this concern.

The primary endpoint has missing data for 14 implants in Group A and 10 implants in Group B. Reasons for missingness and methods for handling it are not reported. The outcome is analyzed at implant level, while the population is described in subject-level ITT terms; the record does not explain this distinction further. It also does not report whether any within-subject dependence was modeled.

Other limitations in the registry record include the absence of a detailed statistical plan, multiplicity strategy, sample-size justification, and interim analysis information. The listed safety counts lack supporting detail about event definitions and observation duration. These points limit interpretation of the posted record; they do not, on their own, establish what analyses or additional information may exist outside it.

16. Related Tutorials

17. Related Statistical Calculators

18. Sources

• ClinicalTrials.gov: A Study Evaluating OsseoSpeed TX Using Different Drilling Protocols With Immediate Loading — NCT01340170.
• Registry record last updated 2024-11-15; status last verified 2024-03.
• Results first posted 2024-11-15.
• 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

NCT01340170 is a completed, open, prospective, multicentre, non-randomized parallel study of the OsseoSpeed TX implant with immediate loading. The registry records enrollment of 168 and lists edentulism as the condition. Its primary endpoint is marginal bone level change, measured radiographically from implant insertion to 12 months post implant insertion and expressed in mm.

The soft bone drilling protocol is described for bone quality 3 and 4; the standard drilling protocol is described for bone quality 1 and 2. The primary outcome is analyzed at implant level, with missing data reported for 14 implants in Group A and 10 implants in Group B. Although the registry describes the study’s rationale and lists secondary outcomes, numerical primary endpoint results and detailed analysis methods are not reported in the registry record. The listed adverse-event categories report 0 serious events, 0 other events, and 0 deaths for each displayed group.