Immediate versus delayed loading of dental implants in the maxillae of minipigs. Part II: histomorphometric analysis.
OBJECTIVE
To assess histomorphometric parameters of dental implants placed in partially edentulous maxillae of minipigs.


METHODS
In 9 minipigs, 6 XiVE implants were placed on each side of the maxilla, either after implant site preparation by an osteotome technique or by spiral drills. The implants were restored with fixed provisional restorations and loaded either immediately or after healing periods of up to 5 months. After a loading period of 6 months, the animals were sacrificed and the implants were retrieved together with the adjacent bone. Histologic specimens were prepared and bone-to-implant contact (BIC) ratio, interthread bone area, and peri-implant bone area were determined.


RESULTS
An analysis of variance revealed that the BIC ratio on the palatal side was significantly influenced by the preparation technique of the implant site (P = .001) and by the healing period (P = .02). After implant site preparation by an osteotome technique, higher BIC values were achieved for implants that were loaded either immediately or after healing periods of 1 to 3 months. After healing periods of 4 to 5 months, implant site preparation with spiral drills showed slightly better results in regard to BIC. Interthread bone area and peri-implant bone area did not differ significantly statistically for the 2 implant placement techniques and the 3 healing periods.


CONCLUSIONS
After 6 months of functional loading in the maxilla, successful immediately loaded implants performed the same as implants subjected to an unloaded healing period prior to loading as far as histomorphometric data were concerned. Prospective randomized clinical studies should be carried out in humans to compare immediate loading to loading after an unloaded healing phase.
Nkenke
Emeka
E
Department of Oral and Maxillofacial Surgery, University of Erlangen-Nuremberg, Germany. emeka.nkenke@mkg.imed.uni-erlangen.de
Fenner
Matthias
M
Vairaktaris
Eleftherios G
EG
Neukam
Friedrich Wilhelm
FW
Radespiel-Tröger
Martin
M
D000704:Analysis of Variance; D000818:Animals; D003758:Dental Implantation, Endosseous / Q000379:methods*; D015921:Dental Implants; D019094:Dental Prosthesis, Implant-Supported; D019232:Dental Restoration Failure; D003799:Dental Stress Analysis; D003831:Denture, Partial, Immediate; D005260:Female; D008437:Maxilla; D016348:Osseointegration; D013552:Swine; D013556:Swine, Miniature
D015921:Dental Implants