Using resorbable screws for fixation of cortical onlay bone grafts: an in vivo study in rabbits.
OBJECTIVE
The purpose of this study is to test bioresorbable screws as an alternative to titanium screw graft fixation. When cortical onlay grafts are used, it is necessary to rigidly immobilize them with titanium screws into the recipient site. The screws must be removed before placing implants into this site. Bioresorbable screws may be an alternative to titanium fixation, eliminating the additional morbidity associated with this.


METHODS
Fifteen New Zealand White rabbits were divided into 3 groups. Bilateral tibial onlay bone grafts were placed in the mandible and secured using titanium fixation, bioresorbable fixation, or no fixation. After 6 weeks, all grafted sites were harvested. Hematoxylin-eosin and Giemsa staining were performed to evaluate inflammation, graft integration, and thickness.


RESULTS
The treatment groups showed evidence of consolidation under light microscopy. Smooth integration of the graft borders with the recipient bone was identified. No integration was seen in the control group. The average thickness of the grafted sites was: 1) bioresorbable, 2.28 mm; 2) titanium, 1.87 mm; and 3) control, 1.06 mm. The differences were statistically significant (P = .0004) between the titanium group and the control group, as well as between the bioresorbable and the control group (P = .01). There was no statistically significant difference between the 2 treatment groups (P = .19).


CONCLUSIONS
The overall thickness of the treatment specimens was greater than that of the control group. The bioresorbable group showed graft integration equal to that of the titanium group, making it an adequate alternative for graft fixation.
Chacon
Guillermo E
GE
Section of Oral and Maxillofacial Surgery, Pathology and Anesthesiology, College of Dentistry, The Ohio State University, Columbus, USA. chacon.4@osu.edu
Ellis
James P
JP
Kalmar
John R
JR
McGlumphy
Edwin A
EA
D020341:Absorbable Implants; D000818:Animals; D001672:Biocompatible Materials / Q000737:chemistry; D016723:Bone Remodeling / Q000502:physiology; D001863:Bone Screws; D016025:Bone Transplantation / Q000295:instrumentation* / Q000473:pathology; D002508:Cephalometry; D006085:Graft Survival / Q000502:physiology; D019344:Lactic Acid / Q000737:chemistry; D008334:Mandible / Q000473:pathology / Q000601:surgery; D010006:Osteoblasts / Q000473:pathology; D011100:Polyglycolic Acid / Q000737:chemistry; D000077182:Polylactic Acid-Polyglycolic Acid Copolymer; D011108:Polymers / Q000737:chemistry; D011817:Rabbits; D011897:Random Allocation; D014025:Titanium / Q000737:chemistry; D014182:Transplantation, Autologous; D014945:Wound Healing / Q000502:physiology
D001672:Biocompatible Materials; D011108:Polymers; D000077182:Polylactic Acid-Polyglycolic Acid Copolymer; D011100:Polyglycolic Acid; D019344:Lactic Acid; D014025:Titanium