Zotelli 2014.

Study characteristics
Methods	Study design: parallel‐group, randomised trial Location: Piracicaba Dental School (FOP‐UNICAMP) in Piracicaba, Sau Paulo, Brazil Setting: dental hospital Number of centres: 1 Total study duration: 7 months (February 2013 to August 2013) Funding source: none declared
Participants	Inclusion criteria: previous history of unpleasant nausea during dental procedures that hindered or prevented the dental treatment from being carried out properly; either sex; age 18 to 85 Exclusion criteria: pregnant women and people who had been taking antiemetic drugs or medications that could produce nausea Age: 19 to 62 years old Gender: male: 11; female: 22 Ethnicity: 27 white; 4 non‐white Number randomised: random assignment of 33 participants (intervention = 17; sham = 16). Study details obtained by personal communication Number evaluated: 33
Interventions	Intervention: acupuncture at P6 Control: sham acupuncture at P6 Details: for the intervention group, a disposable acupuncture needle was placed unilaterally in the right arm with perpendicular insertion angle. For the control group, a retractable needle with blunt tip that does not penetrate the skin was used, which gives the patient a pricking sensation. The needles were in place for 20 minutes and were removed before discharging the patient. The procedure was done by the same experienced and licensed acupuncturist for all participants
Outcomes	Completion of dental procedure: data obtained by personal communication Reduction in gagging Assessed by researcher: Gagging Severity Index (GSI) (evaluated severity of nausea) and Gagging Prevention Index (GPI) (evaluated the treatment effectiveness in controlling nausea) Time point: GSI was assessed prior to acupuncture and GPI was assessed after acupuncture. Both GSI and GPI were assessed in 3 stages of impression taking: when the empty impression tray was tried in the mouth, when the loaded tray was inserted into the mouth and the tolerance of the tray in the mouth until the alginate set Assessed by participant: VAS: it consisted of a horizontal line 10 inches long, with word anchors at both ends with words 'without nausea' at 0 and 'maximum nausea' at 10 Time point: VAS was recorded on 2 occasions, at the end of the first moulding without acupuncture and at the end of the second impression with acupuncture, in both groups Adverse effects: 1 participant reported increased sweating in control group; however, this participant had declared having a fear of needles, which explains the reported effect. In the test group, 11 people reported at least one of the possible sensations of Deqi
Notes	Sample size calculation: sample was defined based on scientific literature, other study authors used similar size of sample (from personal communication) Key conclusions of the study authors: "Acupuncture in PC6 was effective for controlling nausea during maxillary impression" Miscellaneous comments from study authors: "the volunteers' expectations had no influence on reducing nausea"
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Low risk	Randomisation was done using the site http://www.randomizer.org.
Allocation concealment (selection bias)	Unclear risk	"This was a controlled, double‐blind clinical study, in which the researchers and the volunteer patients were not aware of the group to which the volunteers belonged". "...were informed that they would not be aware of the group to which would be assigned to". Comment: Details of allocation concealment not reported in the article and personal communication.
Blinding of participants and personnel (performance bias) All outcomes	Low risk	"This was a controlled, double‐blind clinical study, in which the researchers and the volunteer patients were not aware of the group to which the volunteers belonged". "So that neither the researchers nor the patients were able to differentiate between the real acupuncture and the sham acupuncture, we used the resin ring in both groups, and the patient was covered with a disposable blue sheet of 40 grammage thickness until the end of the procedure". "one (the volunteer researcher) inserted the acupuncture needles and the other (the main researcher) performed the impression‐taking procedures and nausea assessment".
Blinding of outcome assessment (detection bias) All outcomes	Low risk	Quote from control group methodology: "this needle is retractable and has a blunt tip; therefore, it does not penetrate the skin. When it touches the skin, the patient feels a pricking sensation, simulating the puncturing of the skin". "So that neither the researchers nor the patients were able to differentiate between the real acupuncture and the sham acupuncture, we used the resin ring in both groups, and the patient was covered with a disposable blue sheet of 40 grammage thickness until the end of the procedure". "one (the volunteer researcher) inserted the acupuncture needles and the other (the main researcher) performed the impression‐taking procedures and nausea assessment".
Incomplete outcome data (attrition bias) All outcomes	Low risk	All 33 participants were evaluated.
Selective reporting (reporting bias)	Low risk	All outcomes described were reported. Conclusions are in accordance with the results.
Other bias	Low risk	None

IM = intramuscular; IV = intravenous; J = Joules; mW = milliwatts; nm = nanometres; P6 = a point located 3‐finger breadths below the wrist on the inner forearm in between the 2 tendons; TENS = transcutaneous electric nerve stimulation; VAS = visual analogue scale.