title: Self-reinforced polylactide/polyglycolide 80/20 screws take more than 1(1/2) years to resorb in rabbit cranial bone.
abstract: The aim of this study was to assess tissue reactions to bioabsorbable self-reinforced polylactide/polyglycolide (SR-PLGA) 80/20 miniscrews in rabbit cranial bone. One PLGA screw was implanted on one side and one titanium screw on the other side of the sagittal suture (n = 21). Three animals were sacrificed after 2, 4, 8, 16, 24, 54, and 72 weeks. In histological examination the numbers of macrophages, giant cells, active osteoblasts, and fibrous tissue layers were assessed and degradation of the bioabsorbable screws was evaluated. After 2 weeks, macrophages were seen near the heads of both screws. After 4 and 8 weeks, the bioabsorbable screws were surrounded by fibrous tissue. Osteoblastic activity and groups of several giant cells were seen. After 24 weeks, a significant change in the morphology of the PLGA screws had occurred. Osteoblastic activity and the amount of giant cells had decreased. After 1 year, some PLGA biomaterial was still present. PLGA screws had been replaced by adipose tissue, fibrous tissue, and "foamy macrophages" that had PLGA particles inside them. After 1(1/2) years, the amount of biomaterial remaining had decreased remarkably. The particles of biomaterial were inside foamy macrophages. SR-PLGA 80/20 screws are biocompatible and have no clinically manifested complications when used in the cranial bone of rabbits. No contraindications as regards their clinical use in craniofacial surgery was found when these screws were studied in the cranial bones of rabbits.
authors.affiliation: Department of Surgery, Oulu University Hospital, P.O. Box 5000, FIN-90014, University of Oulu, Oulu, Finland. jtiainen@cc.oulu.fi
authors.forename: Johanna
authors.initials: J
authors.lastname: Tiainen
authors.forename: Ylermi
authors.initials: Y
authors.lastname: Soini
authors.forename: Pertti
authors.initials: P
authors.lastname: Törmälä
authors.forename: Timo
authors.initials: T
authors.lastname: Waris
authors.forename: Nureddin
authors.initials: N
authors.lastname: Ashammakhi
mesh_terms: D000818:Animals; D001672:Biocompatible Materials / Q000737:chemistry / Q000378:metabolism*; D001863:Bone Screws; D015726:Giant Cells / Q000166:cytology; D019344:Lactic Acid / Q000378:metabolism*; D008264:Macrophages / Q000166:cytology; D008297:Male; D008422:Materials Testing; D010006:Osteoblasts / Q000166:cytology; D011100:Polyglycolic Acid / Q000378:metabolism*; D000077182:Polylactic Acid-Polyglycolic Acid Copolymer; D011108:Polymers / Q000378:metabolism*; D011817:Rabbits; D012886:Skull / Q000166:cytology / Q000378:metabolism*; D013997:Time Factors; D014025:Titanium / Q000378:metabolism
chemical_list: D001672:Biocompatible Materials; D011108:Polymers; D000077182:Polylactic Acid-Polyglycolic Acid Copolymer; D011100:Polyglycolic Acid; D019344:Lactic Acid; D014025:Titanium