Lee 2013.

Methods	Study design: randomised controlled trial, parallel design Location: Korea Number of centres: 1 Setting: university hospital Recruitment period: unclear Funding source: not reported
Participants	Inclusion criteria: need for a mandibular block; no behavioural management problems; no gender, race, or ethnic restrictions Exclusion criteria: emergency cases were not selected Number of participants randomised: 134 Number of participants evaluated: 134 Number of males/females: 77 males (Group 1: 35, Group 2: 42); 57 females (Group 1: 19, Group 2: 38) Age range: Group 1: 4 to 12 years, Group 2: 3 to 12 years
Interventions	Group 1 (control): conventional delivery of LA Group 2: pulling of mucosa over tip of needle at insertion of LA syringe
Outcomes	Treatments videotaped and assessed using the Sound, Eyes, and Motor (SEM) scale. Results of SEM divided into 2 categories: comfort and discomfort. Discomfort was divided into 3 subscales: mild, moderate, and severe pain. Results reported separately for boys and girls; maxillary and mandibular LA
Notes	The same dentist delivered LA 2 dental students assessed children, intra and interexaminer agreements established at 90% No sample size calculation Consent and ethical approval obtained
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Unclear risk	Quote: "randomly divided into the following 2 groups: alternative and conventional" Comment: not discussed how sequence generation was performed
Allocation concealment (selection bias)	Unclear risk	Allocation concealment not reported
Blinding of participants and personnel (performance bias) All outcomes	High risk	Quote: "this study design was not double blind, i.e., the dentist was aware of the procedure" Comment: it would not be possible for the operator to be blinded to the intervention, but this might have been a source of bias; no reference to blinding of participants
Blinding of outcome assessment (detection bias) All outcomes	High risk	No reference to blinding of assessors. Quote: "Data recorded in the videotape were rated using the Sounds, Eyes, and Motor (SEM) scale by 2 independent evaluators (trained dental students)" Comment: not possible to blind raters to intervention
Incomplete outcome data (attrition bias) All outcomes	High risk	Quote: "Children were excluded if technical problems occurred during the videotaping procedures", however this was not further discussed. No descriptors of how many children were excluded for this reason. Attrition in each group is unclear
Selective reporting (reporting bias)	Low risk	The study reported all expected outcomes
Other bias	Low risk	No further bias identified