Allocation concealment
The participants were assigned after determining their eligibility as per the inclusion criteria and obtaining their informed and written consent to participate. An assistant outside the study prepared sealed and numbered envelopes with the antibiotic or placebo to be administered, according to the instructions. Each number corresponded to the treatment assigned during randomisation, and each patient was successively assigned the corresponding treatment number. One of the researchers delivered the treatment in a closed envelope 1 h before the implant placement. All the professionals directly in contact with the participants and the participants themselves were unaware of the treatment.