| Reference | Comments |
|---|---|
| «Chou YH, Ho PS, Ho KY ym. Association between the ...»1 Chou 2017 | Control of confounding factors (such as age smoking, education, oral hygiene, frequency
of dental checkups) not reported Outcome measurements made by single periodontist, blinding not possible Small sample size |
| «Li ZB, Qu HL, Zhou LN ym. Nonimpacted Third Molars...»2 Li 2017 | Control of confounding factors (such as age smoking, education, oral hygiene, frequency
of dental checkups) not reported Outcome measurements made by single periodontist, blinding not possible Small sample size |
| «Li ZB, Qu HL, Zhou LN ym. Influence of Non-Impacte...»3 Li 2017 | Control of only some confounding factors (age and sex)
Outcome measurements, blinding not possible |
| «Qu HL, Tian BM, Li K ym. Effect of Asymptomatic Vi...»4 Qu 2017 | Outcome measurements made by single periodontist, blinding not possible |
| «Ghaeminia H, Perry J, Nienhuijs ME ym. Surgical re...»5 Ghaeminia 2016 | Retrospective and cross-sectional studies were excluded |
| «Nunn ME, Fish MD, Garcia RI ym. Retained asymptoma...»6 Nunn 2013 | Control of some confounding factors (adjusted for baseline age, smoking status, education
and baseline second molar measures, but not for oral hygiene, frequency of dental
checkups)
Selection of participants in the study; all were males Missing data, of the initial 1231 participants 416 were analyzed after 25 years Outcome measurements, blinding not possible |