Knowledge of soft and hard tissue healing around orthodontic mini-screws can determine guidelines for clinical use. Five beagle dogs were used to study the soft and hard tissue healing of unloaded self-tapping orthodontic mini-screws at intervals of 0, 2, 7, 15 and 30 days after insertion. Bony specimens containing the screws were dissected, fixed, embedded in acrylic resin before being cut. The blades were stained and observed under light microscopy. Soft tissue adaptation at the neck of the screw was excellent from the beginning, forming a barrier against bacterial and foreign body penetration. Junctional epithelium was observed at day 7 and the biologic width observed was comparable to that around prosthetic implants. A blood clot filled the space between the bone and the implant soon after insertion. At day 2 a fibrin network covered the implant surface and inflammatory cells cleaned the surgical wound. At day 7 new bone genesis was observed and osteoid was encountered on the parent lamellar bone. Woven bone was encountered after two weeks in areas where the bone had no immediate direct contact with the implant body. Primary parallel-fiber bone was found after 30 days together with woven bone deposited directly on the implant surface. It is possible to conclude that an immediate and durable soft tissue seal around the implant was obtained soon after insertion. Osseointegration due to direct bone deposition on implant surface was obtained after 30 days.