Study	Reason for exclusion
Al‐Amad 2017	Insufficient follow‐up period length. It is a short‐term study evaluating the effect of rubber dam usage on bacterial contamination of the dentist’s head instead of its influence on dental restorations
Daudt 2013	Inappropriate study design. The study set randomisation and analysis units at tooth level without accounting for the clustering effect of teeth within individual participants
Favetti 2021	Inappropriate study design. The study set randomisation and analysis units at tooth level without accounting for the clustering effect of teeth within individual participants
Ganss 1999	Randomisation allocation not performed between the rubber dam and cotton rolls isolation groups
Huth 2004	Study was a CCT as randomisation allocation was not performed between the 2 treatment groups, and using teeth as the analysis unit
Ibrahim 2020	No dental restoration performed. The study assessed the nature of tooth colour change resulting from dehydration due to rubber dam application before a restoration was placed
Luz 2012	Inappropriate study design. The study employed different restorative treatments and materials on participants of 2 groups, in other words, whether rubber barrier was used was not the only variable
NCT01506830	Inappropriate study design. The study authors kindly provided us with a pre‐publication copy of the study and we were able to see that the study claimed to be performed using a split‐mouth design, but not carried out it in an appropriate way
Raskin 2000	Inappropriate study design. The study set randomisation and analysis units at tooth level without accounting for the clustering effect of teeth within individual participants
Sabbagh 2011	Conference abstract without mentioning randomisation allocation between the 2 treatment groups, and author contact failed
Smales 1993	Study was a CCT as randomisation allocation was not performed between the 2 treatment groups, and using teeth as the analysis unit
Straffon 1985	Randomisation allocation not performed between the rubber dam and cotton roll isolation groups and using tooth surfaces as the analysis unit
van Dijken 1987	Study was a CCT as randomisation allocation was not performed between the 2 treatment groups

CCT: controlled clinical trial.