Table 2 Risk of bias of the included randomized clinical trials with the Cochrane risk of bias tool
Trial | Sequence generation | Allocation concealment | Blinding of participants/personnel | Blinding of outcome assessors | Incomplete outcome data | Selective outcome reporting | Other sources of bias |
|---|---|---|---|---|---|---|---|
Arici et al. [39] | Unclear—no randomization details provided information provided: “Thirty patients (17 girls, 13 boys) were randomly assigned to treatment with a fixed functional orthodontic appliance (Forsus nitinol flat-spring) for 6 to 9 months (mean, 7 months).” | Unclear—no information provided. | Unclear—blinding is impractical for both patients and clinician; outcome is objective, but was not assessed blindly. | High risk—no mention of blinding throughout the paper; blinding could have been implemented. | Low risk—no drop-outs or patient losses are reported. | Unclear—it is difficult to judge whether selective reporting is a problem, as no protocol exists. | Unclear—no definite issue identified (except for a possible confounder of vertical skeletal configuration type). |
Unclear—no randomization details provided: “The Class II subjects were randomly allocated to 2 subgroups, treated and control, to avoid bias in the group comparison.” | Unclear—no information provided. | Low risk—blinding is impractical for both patients and clinician; outcome is objective and was assessed blindly. | Low risk—all images were coded and their order permutated to keep the analyst blind to subject identification group, and timing (T1 or T2). | Low risk—no drop-outs or patient losses are reported. | Unclear—it is difficult to judge whether selective reporting is a problem, as no protocol exists. | Unclear—no definite issue identified (except for a possible confounder of vertical skeletal configuration type). | |
Unclear—no randomization details provided: “The sample was randomly dichotomized into 2 subgroups, treated subjects and untreated controls, to avoid bias in the group comparison.” | Unclear—no information provided. | Low risk—blinding is impractical for both patients and clinician; outcome is objective and was assessed blindly. | Unclear—blinding is mentioned: “A double-blind procedure was used”. However, no details are given and this is not mentioned at all in study published subsequently as dissertation. | Low risk—no drop-outs or patient losses are reported. | Unclear—it is difficult to judge whether selective reporting is a problem, as no protocol exists. | Unclear—no definite issue identified (except for a possible confounder of vertical skeletal configuration type). |