Animal model

Nine clinically healthy New Zealand white rabbits weighing 3.5 kg and more were used for the study, and the animals were housed in the central animal house facility. The head of tibia/femur of the animals were used for the implantation of samples. Rabbits’ tibiae and femur have been widely used as an animal model by various other authors to study osseointegration of dental implants.

Sample size

The sample size of this study has been calculated based on the results of a similar study by Bornstein et al. It was established that 88% statistical power will be achieved by using 18 mini dental implants (3M^™ESPE^™ MDIs) for the experimental implants and equal number of an established regular implant (Ankylos^®, Dentsply Friadent GmbH) for the control. Therefore, the total number of implants used was 36. Each animal received four implants on hind limbs, i.e., right and left tibia/femur head randomly (the heads of tibia and femur have been chosen to get the maximum bulk of bone). Therefore, each animal received two experimental and two regular implants.

Surgical procedure

The procedures were approved by the institutional animals’ ethics review board of McGill University, Canada. Animals were anesthetized by an intravenous injection of ketamine hydrochloride-xylazine mixture at 35–50 and 1–3 mg/kg respectively according to a method described by Green et al. Acepromazine was injected subcutaneously at dosage of 1 mg/kg. Further injections of the mixture were given to maintain anesthesia, if necessary. Sterile ophthalmic ointment was put in both eyes to prevent corneal desiccation. Animals were shaved for twice the size of the expected surgical field with an electric razor. All loose hair and debris from the animal were removed. The surgical area was cleaned with gauze and 2% chlorhexidine solution to remove the majority of debris from the surgical site.