Study	Reason for exclusion
Al‐Zahrani 2009	Cross‐over trial
Arya 2002	Participants not randomly assigned
Badalaty 1990	Cross‐over trial
Baldinelli 1989	No comparison of groups
Berge 1999	No comparison of groups Ages ranging from 3 to 46 years
Blake 1999	Age unclear, authors did not respond Review authors assumed the subjects were adults
Campbell 1998	Participants not randomly assigned (explicitly stated)
Canpolat 2017	Described as deep sedation
Cathers 2005	Cross‐over trial
Chaushu 2002	No comparison of groups
Coldwell 1999	Evaluates adverse effects only
da Costa 2007	Cross‐over trial
Dallman 2001	Cross‐ over trial
Davila 1990	Review
Doring 1985	Not comparative
Downs 1997	Cross‐over trial
Duncan 1984	Survey
Duncan 1994	No comparison of groups
Dunn‐Russell 1993	No comparison of groups
el Magboul 1995	Cross‐over trial
Erlandsson 2001	No comparison of groups
Evans 1966	Cross‐over trial
Flaitz 1985	Cross‐over trial
Fuks 1994	Cross‐over trial
Fukuta 1993	No comparison of groups Ages 4 to 21 years
Fukuta 1994	Ages from 5 to 20 years
Gallardo 1984	Cross‐over trial
Gamonal Aravena 1989	Cross‐over trial
Garton 1970	Review
Haas 1996	Cross‐over trial
Hall 2006	Adults
Hartgraves 1994	Cross‐over trial
Hasty 1991	Cross‐over trial
Heard 2010	Not randomised
Henry 1990	Compares scavenged/non‐scavenged groups with regard to levels of ambient nitrous oxide
Houpt 1985a	Cross‐over trial
Houpt 1985b	Cross‐over trial
Houpt 1989	Cross‐over trial
Houpt 1996	Cross‐over trial
Hulland 2002	Retrospective
Isik 2008	Looked at the effect of flavouring on acceptability of oral sedatives
Jensen 1998	Retrospective study
Kantovitz 2007	Cross‐over trial
Kayalibay 1987	Review
Kerins 2007	Not randomised
Kopel 1971	Not randomised
Koroluk 2000	Retrospective study
Kramer 1991a	No comparison of groups
Kramer 1991b	No comparison of groups
Kupietzky 1996	No relevant outcomes
Lahoud 2001	Pilot study ‐ no comparative group
Leelataweedwud 2001	Retrospective study
Leelataweewud 2000	Cross‐over trial
Lima 2003	Cross‐over trial
Lindh‐Stromberg 2001	No comparison of groups
Lindsay 1980	Cross‐over trial
Lindsay 1985	Cross‐over trial
Litman 1997	Premedication before general anaesthesia
Litman 1998	Not randomised (author contacted)
Lökken 1994	Cross‐over trial
Machen 1977	No relevant outcomes
Malamed 1989	No comparison of groups
Marshall 1999	The study was based on 56 different treatment attempts on 34 patients. Therefore it was a partial cross‐over design as some of the patients would have had more than 1 type of treatment
Martinez 2006	Not randomised
McCann 1996	Cross‐over trial
Milnes 2000	No comparison of groups
Moore 1997	No comparison of groups
Musial 2003	Cross‐over trial
Myers 1977	No comparison of groups
Myers 2004	Cross‐over trial
Nathan 1987	Not randomised
Oei‐Lim 1991	No comparison of groups Ages ranging from 23 to 37 years, mental and physical handicapped
Pandey 2010	Cross‐over trial
Pisalchaiyong 2005	Cross‐over trial
Poorman 1990	Not randomised
Primosch 1999	Cross‐over trial
Primosch 2001	Retrospective study No comparison of groups
Quarnstrom 1992	Not randomised
Ram 1999	Cross‐over trial
Reinemer 1996	Inappropriate design, partial cross‐over with some subjects having both and others only 1 regimen
Robbins 1967	Inappropriate design, partial cross‐over with some subjects having both and others only 1 regimen
Roberts 1979	Age range 4 to 17 years No comparison of groups
Roberts 1982	No comparison of groups
Roberts 1992	Inappropriate design, partial cross‐over with some subjects having both and others only 1 regimen
Robertson 1998	Not randomised (quasi‐randomisation). First patient randomised by toss of a coin, remaining patients alternated
Roelofse 1990	Premedication before general anaesthesia
Roelofse 1993	Premedication before general anaesthesia
Rohlfing 1998	No comparison of groups
Sams 1992	No relevant outcome
Sams 1993b	Review
Sanders 1997	No comparison of groups
Shapira 1992	Cross‐over trial
Shapira 1996	Cross‐over trial
Shapira 2004	Cross‐over trial
Sharma 1992	Inappropriate design (partial cross‐over)
Sheroan 2006	Cross‐over trial
Silver 1994	Ages from 3 to 18 years
Songvasin 1990	Cross‐over trial
Subramaniam 2017	Interventions not randomised: "Based on the parent preference of the route of administration, children were then randomly divided into 2 groups"
Sullivan 2001	Cross‐over trial
Tanaka 2000	General anaesthesia
Tobias 1975	Not randomised
Tsinidou 1992	Cross‐over trial
van der Bijl 1991	Adults
Varpio 1991	Not randomised
Veerkamp 1997	Deep sedation
Whitehead 1988	Not randomised (author contacted to confirm)
Wilson 1990	Retrospective study
Wilson 1992	Dose response study measuring physiological outcomes
Wilson 1993	Cross‐over trial
Wilson 2000	Retrospective study
Wilson 2002	Cross‐over trial
Wilson 2003	Cross‐over trial
Wilson 2006	Cross‐over trial
Wilson 2007	Cross‐over trial
Yanase 1996	Cross‐over trial