Early trabecular bone healing around titanium implants: a histologic study in rabbits.
BACKGROUND
A detailed insight into the early healing response of trabecular bone to unloaded titanium implants is lacking.


METHODS
Cylindrical implants were inserted in the tibial epiphysis of rabbits and left to heal for 1 to 42 days. Samples were processed into paraffin or methylmethacrylate sections and histomorphometrically analyzed.


RESULTS
A hematoma was observed after 1 and 3 days of implant placement. In addition, small fragments of bone trabeculae were detected around the implant as a result of the implant installment procedure. Soon, osteoclasts were observed resorbing these fragments, whereas osteoblasts incorporated them in strands of new bone, thereby making them difficult to distinguish from day 7 onward. At that time, osteoblasts were detected at the edges of the preexisting bone, actively depositing new bone, resulting in maximal osteoid deposition around the implant after 28 days (58%). After 7 days of healing, the presence of basic remodeling units in the surrounding bone was already maximal (P <0.05 versus t = 1 and 3 days). This remodeling activity, together with the new bone formation, provided a firm anchoring of the implant in the trabecular bone.


CONCLUSIONS
This study evaluated the early cellular events in trabecular bone surrounding titanium implants. The insertion of an implant into bone initiates a series of biologic processes, including the formation of a hematoma, shattered bone fragments adjacent to the implantation site, intensive bone remodeling, and the formation of new bone, eventually leading to the osseointegration of the implant.
Slaets
Elke
E
Department of Prosthetic Dentistry, BIOMAT Research Group, Catholic University Leuven, Leuven, Belgium.
Carmeliet
Geert
G
Naert
Ignace
I
Duyck
Joke
J
D000818:Animals; D002467:Cell Nucleus; D003758:Dental Implantation, Endosseous; D015921:Dental Implants; D020007:Implants, Experimental; D016348:Osseointegration; D010006:Osteoblasts / Q000166:cytology; D010010:Osteoclasts / Q000166:cytology; D011817:Rabbits; D018709:Statistics, Nonparametric; D013977:Tibia; D014025:Titanium; D014945:Wound Healing
D015921:Dental Implants; D014025:Titanium