A Reporting-Quality Audit on the Completeness of Sample-Size Parameters of Randomized Controlled Trials Published in Implant Dentistry from 2005-2009 and 2020-2024

Background. Properly calculated sample sizes are essential for the scientific and ethical validity of randomized controlled trials (RCTs). Prior audits in medical and dental fields have documented incomplete reporting of samplesize calculation parameters, but no study has systematically assessed trends in implant dentistry across the pre- and post-CONSORT uptake eras.

Objective. To quantify the completeness of a priori sample-size parameter reporting in implant dentistry RCTs and to compare reporting between 2005–2009 (Period 1) and 2020–2024 (Period 2).

Methods. We searched PubMed (last searched November 2024) for RCTs published in six implant dentistry journals, limited to English-language articles with free full text. Two trained reviewers divided the screening and scoring. For each trial, we recorded whether a sample-size calculation was declared and whether four parameters were reported: type I error (α), power (1−β), variability/effect, and minimum clinically relevant difference (MCRD)/effect. The primary outcome was a completeness score (0–4). Means were compared with Welch’s t-test, corroborated by Mann–Whitney U. Inter-rater reliability was assessed on a 20% re-scored subset (κw = 0.90, 95% CI 0.76–0.98).

Results. Of 341 records retrieved, 259 RCTs met eligibility (Period 1: 52; Period 2: 207). Mean completeness increased from 1.25 ± 1.70 to 2.88 ± 1.64 (Δ = +1.63; Welch p = 2.59×10⁻⁸; Hedges’ g = 0.98, 95% CI 0.67– 1.30). Item-wise reporting improved for all parameters: sample-size calculation declaration 36.5% to 82.1%; α 38.5% to 74.9%; power 25.0% to 74.4%; variability/ effect 30.8% to 69.6%; MCRD/effect 30.8% to 68.6%. A sensitivity analysis removing the double-credit rule for standardized effect sizes confirmed robustness (P2 mean 2.76, still highly significant).

Conclusion. Reporting of sample-size parameters in implant dentistry RCTs improved substantially between the two periods. However, variability and MCRD remain underreported in roughly one-third of recent trials, suggesting that targeted editorial guidance and standardized templates could close the remaining gap.