Randomizations occurred from 11 January 2001 to 29 October 2005 using permuted blocks to maintain allocation concealment.
Studies that used a method of randomization that did not maintain allocation concealment, such as alternate days or medical record numbers (that is to say. were pseudo-randomized) were recorded as not maintaining allocation concealment.
In contrast, study design to maintain allocation concealment was conducted or reported in less than half of the reviewed RCTs.
To maintain allocation concealment, randomisation is performed in real time by a web interface (Filemaker Server Advanced, Filemaker Inc, Santa Clara, California, USA).
Study personnel will be unaware of treatment allocation prior to the assignment of interventions, using sequentially numbered, opaque, sealed envelopes to maintain allocation concealment.
Therefore, the presence of methods to maintain allocation concealment was the only study quality factor used to assess for influence on the pooled effect estimate.
To maintain allocation concealment and minimise selection bias the dental assistants are unaware of the colour codes and block sizes used for randomisation.
Failure to maintain allocation concealment or blinding in trials has been associated with inflated effect estimates [ 2, 5, 15, 46, 47].
Two trials at high risk of bias for sequence generation were included post hoc, but steps to maintain allocation concealment and blinding minimised the possibility that participants were treated differently between groups.
In order to maintain allocation concealment, the assigned intervention (ie, dual-ring wound protector or standard of care) will be provided to the surgeon in an opaque, sealed envelope immediately before surgery by the research assistant.
