Table 6. Risk of bias of included randomized controlled trials in the systematic review.

Study	Randomization process	Deviations from intended interventions	Missing outcome data	Measurement of the outcome	Selection of the reported result	Overall bias
Bjorksved et al. (2018) [40]	Low risk. Study participants were randomly allocated in blocks of different sizes, according to a computer-generated randomization list, using concealed allocation	High-risk. Blinding of participants and people delivering the intervention cannot be performed. We judge that the outcome is influenced by a lack of blinding	Low risk. No dropouts were reported	Low risk. “Single blinding was employed in this trial regarding outcome measure assessment and data analysis”	Low risk. The protocol for the study was registered on ClinicalTrials.gov (study ID: NCT02186548) and the outcomes mentioned in the protocol have been reported	High risk
Smailiene et al. (2013) [7]	High risk. No random element was used in generating the allocation sequence. "Every second patient was assigned to one of the study groups"	Some concerns. Blinding of participants and people delivering the intervention cannot be performed. We judge that the outcome might be influenced by a lack of blinding	Low risk. No dropouts were reported	Some concerns. No details of blinding the measurement stage. "The post-treatment examination was performed by other authors"	Low risk. The protocol was not registered. But the pre-defined outcomes mentioned in the methods section seemed to have been reported	High risk
Smailiene et al. (2013) [42]	High risk. No random element was used in generating the allocation sequence. "Every second patient was assigned to one of the study groups"	Some concerns. Blinding of participants and people delivering the intervention cannot be performed. We judge that the outcome might be influenced by a lack of blinding	Low risk. No dropouts were reported	Some concerns. No details of blinding the measurement stage. "The post-treatment examination was performed by other authors"	Low risk. The protocol was not registered. But the pre-defined outcomes mentioned in the methods section seemed to have been reported	High risk
Fischer (2007) [31]	High risk. No mention of the method used for randomization	Low risk. Blinding of participants and people delivering the intervention cannot be performed. We judge that the outcome is not likely to be influenced by a lack of blinding	Low risk. No dropouts were reported	Some concerns. No details of blinding the measurement stage. "The orthodontist had no knowledge as to which canine had the corticotomy procedure"	Low risk. The protocol was not registered. But the pre-defined outcomes mentioned in the methods section seemed to have been reported	High risk
Gharaibeh and Al-Nimri (2008) [12]	High risk. No mention of the method used for randomization. "The choice of the exposure type was randomly selected"	Low risk. Blinding of the participating patient and the treating clinician was not possible due to the nature of the trial	Low risk. No dropouts were reported	High risk. No details of blinding the measurement stage (data collection) and data analyzer	Low risk. The protocol was not registered. But the pre-defined outcomes mentioned in the methods section seemed to have been reported	High risk
Parkin et al. (2012) [17]	Low risk. The randomization was undertaken using computer-generated random numbers to ensure that equal numbers were allocated to each intervention and allocation concealment was with consecutively-numbered, sealed, opaque envelopes	Some concerns. No details about blinding, either the patient or clinician of the type of mechanical intervention used	Low risk. No dropouts were reported	Some concerns. The examiners were masked as to the patient’s group allocation when undertaking the clinical examinations. The patient details were removed from all study models and radiographs, which were only labeled with the participant randomization number. No details about blinding the examiners or the type of mechanical intervention used	Low risk. The protocol was not registered. But the pre-defined outcomes mentioned in the methods section seemed to have been reported	Some concerns
Parkin et al. (2013) [41]	Low risk. The randomization was undertaken using computer-generated random numbers in randomly allocated blocks of 2, 4, 6, and 8 to ensure that there were equal numbers allocated to each intervention. Allocation concealment was with consecutively numbered, sealed, opaque envelopes	Some concerns. Blinding of participants and people delivering the intervention cannot be performed. We judge that the outcome might be influenced by a lack of blinding	Low risk. No dropouts were reported	Some concerns. No details of blinding the measurement stage (data collection) and data analyzer. "A masked assessor probably be able to guess which canine was previously impacted, owing to positional differences, but would not be able to tell which technique was used"	Low risk. The protocol was not registered. But the pre-defined outcomes mentioned in the methods section seemed to have been reported	Some concerns
Dehis et al. (2018) [43]	Low risk. Randomization was carried out by using computer-generated random numbers	High risk. No blinding, but we judge that the outcome is influenced by the lack of blinding	Low risk. No dropouts were reported	High risk. No details of blinding the measurement stage (data collection) and data analyzer	Low risk. The protocol for the study was registered on ClinicalTrials.gov (study ID: NCT03260829) and the outcomes mentioned in the protocol have been reported	High risk