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Aim: Selective outcome reporting (SOR) is a type of bias that occurs when the primary outcome of a trial protocol is changed or omitted in the paper. The purpose of this study was to evaluate the prevalence of SOR in publications of randomized clinical trials (RCT) concerning dental implants. Materials and Methods:Two reviewers independently screened protocols registered at ClinicalTrials.gov until February/2019. If the protocol met the eligibility criteria, the reviewers tried to identify the corresponding publication. Data extraction was carried out by the same reviewers. Primary and secondary outcomes were recorded for each trial and compared to outcomes previously described in protocols. Results:A total of 49 protocols were included. SOR was identified in 27 (55.1%) trials.The major discrepancies were as follows: protocol-defined primary outcome omitted in the publication (n = 6, 12.2%), new primary outcome introduced (n = 8, 16.3%), discrepancy in the primary outcome time frame (n = 17, 34.7%) and new secondary outcome introduced (n = 31, 63.3%). SOR was significantly associated with industry funding (p = 0.04) and timing of registration (p = 0.04). Conclusions:Our results indicate a high rate of SOR in dental implants clinical trials.Use of registry data during the peer-review process may help decreasing SOR. K E Y W O R D S dental implant, randomized clinical trials, selective reporting | 759 SENDYK Et al. S U PP O RTI N G I N FO R M ATI O N Additional supporting information may be found online in the Supporting Information section at the end of the article. How to cite this article: Sendyk DI, Rovai ES, Souza NV, Deboni MCZ, Pannuti CM. Selective outcome reporting in randomized clinical trials of dental implants. J Clin Periodontol. 2019;46:758-765. https ://doi.

Background Outcome discrepancies between protocols and respective publications represent a concerning bias. The purpose of this study was to assess the prevalence of selective outcome reporting (SOR) in root coverage randomized clinical trials (RCTs). Methods Published root coverage RCTs (July 2005 to March 2020) were included if a corresponding protocol could be identified in a public registry. Discrepancies between protocol and its correspondent publication(s) were compared regarding primary and secondary outcomes and other study characteristics. Associations between trial characteristics and SOR were evaluated. Results Forty four studies (54 publications) were included. The majority of studies (77.3%) were retrospectively registered. SOR was frequent (40.9% of trials) and consisted of primary outcome downgrade (22.7%); secondary outcome upgrade (11.4%); new primary outcome introduced in publication (25%); protocol primary outcome omitted from publication (13.6%) and discrepancy in primary outcome timing (18.2%). SOR was unclear in 20.5% of studies and favoured statistical significance in 12 studies (27.3%). SOR was significantly associated with study significance (p < 0.001) and unclear outcome definition in the publication (p < 0.001). Only a third (32.8%) of primary outcomes were completely defined. Conclusions The present study identified high prevalence of SOR in root coverage RCTs.

Randomized clinical trials (RCTs) are human studies carried out to compare different treatments or interventions, and their results are used to support clinical decision-making and improve patient care. Herein, the aim of this study was to review the selection process of study outcomes in periodontology. Primary outcomes should draw the main conclusions of the study, whereas secondary outcomes should only be used to help explain the main findings and generate future research hypothesis. Outcomes are classified as clinically relevant (CROs) or surrogate outcomes. CROs -the first option for primary outcome variables -should convey not only substantial health benefits, but also be deemed important by patients. In periodontology, tooth loss/retention and oral health-related quality of life (OHRQoL) are examples of CROs. While tooth loss has main limitations as a primary outcome, emerging evidence suggest that patient-reported outcome measures (PROMs) can accurately detect OHRQoL following periodontal therapy. When CROs cannot be assessed, validated surrogate outcomes can be used as proxies. Primary outcome variables should reflect a treatment endpoint at the patient level that can be easily used to inform decision-making in daily practice. These outcomes should allow the implementation of a treat-to-target concept in which the intervention can be clearly judged against a prespecified treatment target. Recently, the presence of at most 4 sites with periodontal probing depth ≥5 mm post-treatment was suggested as an effective endpoint for periodontal trials. In perspective, a combination of validated clinical parameters and PROMs will provide a more comprehensive assessment of periodontal treatments.

Selective outcome reporting (SOR) is a type of bias that can compromise the validity of results and affect evidence‐based practice. SOR can overestimate the effect of an intervention and lead to conclusions that a treatment is effective when it is not. This study aimed to investigate the prevalence of SOR in publications of RCTs on nonsurgical periodontal therapy (NSPT) and to verify associated factors. The protocols were searched and selected on the http://www.clinicaltrials.gov platform up to January 16, 2022. Corresponding publications were identified, and data extraction and discrepancy analysis were performed. The risk of bias was assessed according to the RoB2 tool. One hundred forty‐five studies (174 publications) were included. The prevalence of SOR was 49.7% and was unclear in nearly one third of studies (27.6%). Only 31.7% of the primary outcomes were completely described in the publications. The overall risk of bias was high in 60% of the included studies. SOR was associated with statistical significance (p < .001), and multiple publications of the same study (p = .005). Our study demonstrated the high prevalence of SOR, highlighting the need to improve the quality of reporting of RCTs on NSPT studies.