title: Effect of beta-tricalcium phosphate particles with varying porosity on osteogenesis after sinus floor augmentation in humans.
abstract: This study examines the effect of two beta-tricalcium phosphate (TCP) particulate bone grafting materials with varying porosity on bone formation and on osteogenic marker expression 6 months after sinus floor augmentation. Unilateral sinus grafting was performed in 20 patients using a combination (4:1 ratio) of beta-TCP particles with 35% porosity (TCP-C) or 65% porosity (TCP-CM) and autogenous bone chips. At implant placement cylindrical biopsies were sampled and processed for immunohistochemical analysis of resin embedded sections. Sections were stained for collagen type I (Col I), alkaline phosphatase (ALP), osteocalcin (OC) and bone sialoprotein (BSP). Furthermore, the area fraction of newly formed bone as well as the particle area fraction were determined histomorphometrically first, apically close to the Schneiderian membrane and second, in the center of the cylindrical biopsies. In the TCP-CM patient group a larger amount of bone formation and particle degradation was observed in the apical area and thus at the largest distance from the crestal bone compared to the TCP-C group. Good bone bonding behaviour was observed with both materials. This was accompanied by expression of ALP, Col I, BSP and OC in the newly formed bone and osteogenic mesenchym in contact with the degrading particles. Both TCP materials supported bone formation in the augmented sinus floor. Six months after implantation of both types of beta-TCP particles, bone formation and matrix mineralization was still actively progressing in the tissue surrounding the particles. Consequently, a greater porosity appears to be advantageous for enhancing bone formation and particle degradation.
authors.affiliation: Department of Experimental Dentistry, Campus Benjamin Franklin, Charité-University Medical Center Berlin, Abmannshauser Strasse 4-6, D-14197 Berlin, Germany. christine.knabe@charite.de
authors.forename: Christine
authors.initials: C
authors.lastname: Knabe
authors.forename: Christian
authors.initials: C
authors.lastname: Koch
authors.forename: Alexander
authors.initials: A
authors.lastname: Rack
authors.forename: Michael
authors.initials: M
authors.lastname: Stiller
mesh_terms: D000328:Adult; D000368:Aged; D018786:Bone Substitutes / Q000627:therapeutic use*; D002130:Calcium Phosphates / Q000737:chemistry / Q000627:therapeutic use*; D024042:Collagen Type I / Q000378:metabolism; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D007150:Immunohistochemistry; D008297:Male; D008443:Maxillary Sinus / Q000166:cytology* / Q000601:surgery*; D008875:Middle Aged; D015675:Osteocalcin / Q000378:metabolism; D010012:Osteogenesis / Q000502:physiology*; D016062:Porosity; D013997:Time Factors; D016896:Treatment Outcome
chemical_list: D018786:Bone Substitutes; D002130:Calcium Phosphates; D024042:Collagen Type I; C485817:beta-tricalcium phosphate; D015675:Osteocalcin