The effect of an immunosuppressive therapy and its withdrawal on bone healing around titanium implants. A histometric study in rabbits.
BACKGROUND
Immunosuppressive agents have been recognized as a factor affecting bone metabolism. We investigated the consequences of the administration and withdrawal of cyclosporin A/nifedipine on bone around titanium implants to observe whether these changes occur and if they are reversible.


METHODS
Twenty-eight New Zealand rabbits were included in the study. Following anesthesia, the tibiae surface was exposed, and 2 screw-shaped implants 7.0 mm in length and 3.75 mm in diameter were placed bilaterally. The animals were randomly assigned to 1 of 4 experimental groups and received daily subcutaneous injections for 14 days: groups A and C were injected with vehicle while groups B and D received cyclosporin A (10 mg/kg) plus nifedipine (0.5 mg/kg). Groups A and B were sacrificed 14 days and groups C and D 42 days postoperatively. The degree of bone contact with the implant surface and the bone area within the limits of the threads of the implant were measured.


RESULTS
Intergroup analysis revealed no significant difference (P > 0.05) in the degree of bone contact with the implant surface between the control and test groups on days 14 and 42. In contrast, the treated animals demonstrated a significant (P < 0.05) decrease in the bone area within the limits of the threads of the implant in both periods.


CONCLUSIONS
The data of the present study suggest that the use of cyclosporin A/nifedipine may influence bone healing around titanium implants. This observation may have important clinical implications.
Duarte
P M
PM
Department of Prosthodontics and Periodontics, Division of Periodontics, School of Dentistry at Piracicaba, UNICAMP, São Paulo, Brazil.
Nogueira Filho
G R
GR
Sallum
E A
EA
de Toledo
S
S
Sallum
A W
AW
Nociti Júnior
F H
FH
D000818:Animals; D001842:Bone and Bones / Q000187:drug effects* / Q000473:pathology; D002121:Calcium Channel Blockers / Q000008:administration & dosage / Q000494:pharmacology; D004396:Coloring Agents; D016572:Cyclosporine / Q000008:administration & dosage / Q000494:pharmacology; D015921:Dental Implants; D017267:Dental Prosthesis Design; D004338:Drug Combinations; D005500:Follow-Up Studies; D007166:Immunosuppressive Agents / Q000008:administration & dosage / Q000494:pharmacology*; D007279:Injections, Subcutaneous; D009543:Nifedipine / Q000008:administration & dosage / Q000494:pharmacology; D016348:Osseointegration; D014677:Pharmaceutical Vehicles; D011817:Rabbits; D011897:Random Allocation; D013223:Statistics as Topic; D018709:Statistics, Nonparametric; D013977:Tibia; D014025:Titanium; D015431:Weight Loss; D014945:Wound Healing / Q000187:drug effects
D002121:Calcium Channel Blockers; D004396:Coloring Agents; D015921:Dental Implants; D004338:Drug Combinations; D007166:Immunosuppressive Agents; D014677:Pharmaceutical Vehicles; D016572:Cyclosporine; D014025:Titanium; D009543:Nifedipine