Table 4 Risk of bias. According to Chee et al. (2016) [7] and the Cochrane Handbook by Schmucker et al. (2017) [18] Cochrane Germany
Elwakeel and Hazaa (2015) [29] | Deore et al. (2014) [30] | Elkhouli (2011) [13] | El-Sharkawy et al. (2010) [31] | Martinez et al. (2014) [31] | Keskiner et al. (2017) [32] | |
|---|---|---|---|---|---|---|
General bias | ||||||
study design | 1 | 1 | 1 | 1 | 1 | 1 |
randomisation | 1 | 1 | 1 | 1 | 1 | 1 |
blinding | 1 | 1 | 1 | 1 | 1 | 1 |
clear definition of inclusion and exclusion criteria | 1 | 0 | 1 | 1 | 1 | 1 |
number of study participants | 1 | 1 | 1 | 1 | 1 | 1 |
number of participants per study group | 1 | 1 | 0 | 1 | 1 | 1 |
clear definition of the experimental groups | 1 | 1 | 1 | 1 | 1 | 1 |
drop-out | 1 | 1 | 1 | 1 | 1 | 1 |
control of the compliance of the participants | 1 | 1 | 1 | 1 | 1 | 1 |
presentation of significant results | 1 | 1 | 1 | 1 | 1 | 1 |
Omega-3-bias | ||||||
clear details of the medication and composition | 1 | 1 | 1 | 1 | 1 | 1 |
clear indication of dosage | 1 | 1 | 1 | 1 | 1 | 1 |
clear indication of the duration of the medication | 1 | 1 | 1 | 0 | 1 | 1 |
clear indication of placebo (composition) | 1 | 1 | 0 | 0 | 0 | 0 |
Periodontitis bias | ||||||
periodontal disease | 1 | 1 | 1 | 1 | 1 | 1 |
selection of patients | 1 | 0 | 1 | 1 | 1 | 1 |
treatment | 1 | 1 | 1 | 1 | 1 | 1 |
periodontal parameters / indices | 1 | 1 | 1 | 1 | 1 | 1 |
number of examiners | 1 | 1 | N/A | 0 | 0 | 1 |
calibration of the examiner | N/A | N/A | N/A | 1 | 1 | 1 |
time of recording of periodontal parameters | 1 | 1 | 1 | 1 | 1 | 1 |
systemic diseases | 1 | 1 | 1 | 1 | 1 | 1 |
smoker | 1 | 1 | 1 | 1 | 1 | 1 |
Proportion | 95% | 87% | 83% | 87% | 87% | 95% |