Study	Reason for exclusion
Braff 1975	Retrospective Not randomised Went on to limit within selected group of 131 PMCs (on basis of treating dentist and failure to fulfil follow‐up criteria) leaving only 76 PMCs with presented data
Einwag 1996	Retrospective Not randomised Selected group of participants initially and only 66 out of 106 traced for follow‐up
Eriksson 1988	Unclear whether retrospective or prospective Not randomised ‐ PMC placed on tooth in worst condition
Farooq 2000	Retrospective Not randomised
Holan 2002	Retrospective Not randomised Primary outcome related to success of pulpotomy treatment, so related to restoration rather than success of restoration itself
Leith 2011	Compared 2 types of veneered preformed metal based crowns, not different methods of restoration
Roberts 2005	Not randomised Although prospective, treatment was dictated by clinical status of tooth
Zagdwon 2003	Crowns were placed on permanent teeth

Abbreviation

PMC = preformed metal crown