Histodynamics of bone tissue formation around immediately loaded cylindrical implants in the rabbit.
OBJECTIVE
The local mechanical environment influences early peri-implant tissue formation. It is still unclear whether immediate loading limits or promotes peri-implant osteogenesis and which mechanical parameters are important herein. The present study evaluated the influence of well-controlled mechanical stimuli on the tissue response around immediately loaded cylindrical turned titanium implants at two different observation periods.


METHODS
A repeated sampling bone chamber, consisting of dual-structure perforated hollow cylinders with a cylindrical implant, was installed in the tibia of 14 rabbits and used to conduct three displacement-controlled immediate loading experiments: (i) 30 microm - 400 cycles/day - 1 Hz frequency - 2 x/week - 6 weeks; (ii) 30 microm - 400 cycles/day - 1 Hz - 2 x/week - 6 weeks, followed by another 6 weeks with a 50 microm - 800 cycles/day - 1 Hz - 2 x/week loading protocol; and (iii) 0 microm implant displacement for 12 weeks. A linear mixed model and logistic mixed model with alpha=5% were conducted on the data set.


RESULTS
The tissue area fraction was significantly the highest after 12 weeks of loading. The bone area fraction was significantly different between all three loading conditions, with the highest values for the 12-week loading experiment. Twelve-week stimulation resulted in a significantly higher mineralized bone fraction than 6 weeks. Loading did have a significantly positive effect on the mineralized bone fraction. The incidence of osteoid-to-implant and bone-to-implant contact increased significantly when loading the implant for 12 weeks.


CONCLUSIONS
Immediate loading had a positive effect on the tissue differentiation and bone formation around cylindrical turned titanium implants. Controlled implant micro-motion up to 50 microm had a positive effect on the bone formation at its interface.
Vandamme
Katleen
K
Department of Prosthetic Dentistry/BIOMAT Research Group, School of Dentistry, Oral Pathology and Maxillofacial Surgery, Faculty of Medicine, K. U. Leuven, Leuven, Belgium.
Naert
Ignace
I
Geris
Liesbet
L
Sloten
Jozef Vander
JV
Puers
Robert
R
Duyck
Joke
J
D000818:Animals; D001696:Biomechanical Phenomena; D003758:Dental Implantation, Endosseous / Q000295:instrumentation; D015921:Dental Implants; D003799:Dental Stress Analysis; D005260:Female; D020007:Implants, Experimental; D016348:Osseointegration / Q000502:physiology*; D011817:Rabbits; D012044:Regression Analysis; D013977:Tibia; D013997:Time Factors; D014025:Titanium
D015921:Dental Implants; D014025:Titanium