Lu 2000.

Study characteristics
Methods	Study design: randomised, parallel‐group (8 arms), controlled trial Location: University of Pennsylvania, Einstein College of Medicine, Bronx, New York (university hospital), USA Number of centres: 1 Recruitment period: not reported Funding source: not reported
Participants	Inclusion criteria: patients with severe gag reflex requiring any dental treatment (Impression, restoration, scaling/curettage to prophylaxis paste) Exclusion criteria: not reported Age: 17 to 76 years old Gender: not reported Number randomised: not reported Number evaluated: 230
Interventions	Type of intervention: acupuncture (TENS) acupressure at P6 conscious sedation and acupuncture at P6 conscious sedation and acupressure at P6 Control: placebo Dosage: for sedation: any of the following: 30% N2O inhalation 5.0 mg midazolam IV/IM 250 mg trimethobenzamide HCl po Total number of intervention groups: 3 groups (with 3 subgroups for Group 2 and 4 for Group 3 respectively): Group 1: acupuncture at P6 point versus dummy Group 2: acupressure with thumb pressure versus dummy acupressure with sea band versus dummy acupressure with device versus dummy Group 3: acupuncture at P6 point + conscious sedation versus dummy acupressure with thumb pressure + conscious sedation versus dummy acupressure with device + conscious sedation versus dummy acupressure with sea band + conscious sedation versus dummy Duration of treatment: for impression: 5 minutes stimulation was done during and prior to procedure for other dental procedure: 3 minutes stimulation was done during and prior to procedure Duration of follow‐up: no follow‐up
Outcomes	Completion of dental procedure: reported Completion of dental procedure as assessed by researcher/dentist*: reported as excellent, good, fair, poor: excellent: patient made no gagging noise and patient rarely moved good: patient had gagging caused some body movement and retching but not enough to interfere with completion of the work fair: patient encountered gagging and retching severe enough to interrupt the dental work but allowed completion poor: there was no obvious effect and patients movement and gagging was severe and did not allow completion of work * Completion of procedure: excellent, good and fair / Procedure incomplete: poor Reduction in gagging assessed by participant: reported as excellent, good, fair, poor*: excellent: patient experienced no gagging felt very comfortable and not tensed good: patient experienced mild gagging sometimes felt tensed but mostly at ease fair: patient experienced moderate gagging and felt calm sometimes and tensed sometimes poor: severe gagging and patient was tensed all the time * Reduction in gagging: excellent, good and fair / No reduction: poor Health‐related quality of life: not reported Adverse effects: not reported
Notes	Sample size calculation: not reported Key conclusions of the study authors: "The P6 point has remarkable anti‐gagging effects if stimulation is applied correctly. Clinicians may apply thumb pressure at the P6 point to achieve some effect, although this is not as effective as acupuncture. Nevertheless, a substantial percentage of gagging patients would be able to go through dental procedures without gagging when the P6 point is stimulated"
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Unclear risk	Method not described. Quote: "The patients were randomised into three groups"
Allocation concealment (selection bias)	Unclear risk	Not reported
Blinding of participants and personnel (performance bias) All outcomes	Unclear risk	Not reported
Blinding of outcome assessment (detection bias) All outcomes	Unclear risk	Not reported
Incomplete outcome data (attrition bias) All outcomes	Unclear risk	Not reported
Selective reporting (reporting bias)	Low risk	All outcomes described were reported. Conclusions are in accordance with the results
Other bias	Low risk	None