Tahmassebi 2009.

Methods	Study design: randomised controlled trial, parallel design Location: United Kingdom Number of centres: 1 Setting: hospital Recruitment period: not reported Funding source: not reported
Participants	Inclusion criteria: children aged between 3 and 10 years inclusive, no previous dental experience, in need of at least 1 maxillary restoration LA, mentally capable of communicating, satisfying the criteria of group I of the ASA guidelines as issued by the American Association of Anesthesiologists (1963) and who understood English Exclusion criteria: medically and mentally compromised children, children with previous dental experience, children with a history of significant behaviour management problems, children referred specifically because of needle‐phobia and where consent from parent or guardian was not possible Number of participants randomised: 38 Number of participants evaluated: 38 (Group 1: 18, Group 2: 20) Number of males/females: 16 males and 22 females (Group 1: 10 males and 8 females; Group 2: 6 males and 14 females) Age range: 39 to 120 months Mean age: 81.9 months; SD ± 23.2 months
Interventions	Group 1 (control): delivery of maxillary LA using a conventional syringe (buccal, intrapapillary and palatal infiltrations) Group 2: delivery of maxillary LA using the wand (buccal and direct infiltrations delivered)
Outcomes	Anxiety: rated by the participants using a Venham's scale Pain perception: rated by children after delivery of LA, using a modified VAS after LA Child's pain experience: rated for each child by operator using a standard VAS Parents rated chid's pain: using a standard VAS
Notes	There was a sample size calculation Ethical approval and consent were obtained Same operator, standardised speech during delivery of LA Children with no experience of LA Participants not matched for gender
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Unclear risk	Quote: "The supervisor (JT) controlled the randomisation" but no discussion of the process of randomisation used
Allocation concealment (selection bias)	Low risk	Quote: "the operator (MN) was blind to the block size, and was given a list of envelopes to provide the injection to patients. Each envelope was opened immediately before the LA"
Blinding of participants and personnel (performance bias) All outcomes	High risk	Quote: "The subjects were not 'blinded' to the method of LA used" Comment: although it would have been difficult for the participants to be blinded, this may have introduced bias to the study. Not reported if operator was blinded but would not have been possible to do so
Blinding of outcome assessment (detection bias) All outcomes	High risk	As the operator rated each participant using a modified VAS, this may have introduced additional bias, as he was not blinded to the intervention
Incomplete outcome data (attrition bias) All outcomes	Low risk	No excluded participants
Selective reporting (reporting bias)	Low risk	All recorded outcomes were reported on within the results section
Other bias	Low risk	No further bias identified