title: Collagen type I coating stimulates bone regeneration and osteointegration of titanium implants in the osteopenic rat.
abstract: OBJECTIVE
  To investigate the effects of titanium implants functionalised with collagen type I (TiColl) on bone regeneration and osteointegration in a healthy and osteopenic rat animal model.
  
  
  METHODS
  TiColl screws were implanted into the femoral condyles of healthy and osteopenic rats and compared with acid-etched titanium (Ti) screws. The osteointegration process was evaluated by a complementary approach combining microtomographic, histological, histomorphometric and biomechanical investigations at four and 12 weeks.
  
  
  RESULTS
  The TiColl screw also ensured a greater mechanical stability; the push-out values for TiColl screws increased from four to 12 weeks (+28 %). The energy necessary to detach the bone from the screw was significantly higher for TiColl-functionalised screws in comparison to Ti screws (+23 %) at 12 weeks. Histomorphometric investigation revealed that total bone-to-implant contact was higher in TiColl screws in comparison to Ti screws (P < 0.05) and at epiphyseal level, increased bone-to-implant contact was found with TiColl screws in comparison to Ti screws (P < 0.05) in an ovariectomy (OVX) condition. A significant increase in the measured total bone ingrowth from four to 12 weeks was detected for both materials, but more significant for the TiColl material (P < 0.0005). Finally, bone ingrowth in the TiColl group was significantly higher (P < 0.005) in comparison to that of Ti screws in the SHAM condition at metaphyseal level at 12 weeks.
  
  
  CONCLUSIONS
  The present results showed that TiColl is effective in promoting implant osteointegration even in compromised bone.
authors.affiliation: Laboratory of Biocompatibility, Technological Innovations and Advanced Therapies, RIT Department, Rizzoli Orthopaedic Institute, via di Barbiano 1/10, 40136, Bologna, Italy. maria.sartori@ior.it.
authors.forename: Maria
authors.initials: M
authors.lastname: Sartori
authors.affiliation: Laboratory of Preclinical and Surgical Studies, Rizzoli Orthopaedic Institute, via di Barbiano 1/10, 40136, Bologna, Italy.
authors.forename: Gianluca
authors.initials: G
authors.lastname: Giavaresi
authors.affiliation: Laboratory of Biocompatibility, Technological Innovations and Advanced Therapies, RIT Department, Rizzoli Orthopaedic Institute, via di Barbiano 1/10, 40136, Bologna, Italy.
authors.forename: Annapaola
authors.initials: A
authors.lastname: Parrilli
authors.affiliation: Laboratory of Preclinical and Surgical Studies, Rizzoli Orthopaedic Institute, via di Barbiano 1/10, 40136, Bologna, Italy.|Department of Medical and Surgical Sciences (DIMEC), University of Bologna, via Massarenti 9, 40138, Bologna, Italy.
authors.forename: Andrea
authors.initials: A
authors.lastname: Ferrari
authors.affiliation: Laboratory of Preclinical and Surgical Studies, Rizzoli Orthopaedic Institute, via di Barbiano 1/10, 40136, Bologna, Italy.
authors.forename: Nicolò Nicoli
authors.initials: NN
authors.lastname: Aldini
authors.affiliation: Nobil Bio Ricerche SRL, Via Valcastellana 26, 14037, Portacomaro d'Asti, AT, Italy.
authors.forename: Marco
authors.initials: M
authors.lastname: Morra
authors.affiliation: Nobil Bio Ricerche SRL, Via Valcastellana 26, 14037, Portacomaro d'Asti, AT, Italy.
authors.forename: Clara
authors.initials: C
authors.lastname: Cassinelli
authors.affiliation: Nobil Bio Ricerche SRL, Via Valcastellana 26, 14037, Portacomaro d'Asti, AT, Italy.
authors.forename: Daniele
authors.initials: D
authors.lastname: Bollati
authors.affiliation: Laboratory of Biocompatibility, Technological Innovations and Advanced Therapies, RIT Department, Rizzoli Orthopaedic Institute, via di Barbiano 1/10, 40136, Bologna, Italy.|Laboratory of Preclinical and Surgical Studies, Rizzoli Orthopaedic Institute, via di Barbiano 1/10, 40136, Bologna, Italy.
authors.forename: Milena
authors.initials: M
authors.lastname: Fini
mesh_terms: D000818:Animals; D001851:Bone Diseases, Metabolic / Q000601:surgery*; D001861:Bone Regeneration / Q000187:drug effects / Q000502:physiology; D001863:Bone Screws; D020099:Coated Materials, Biocompatible; D024042:Collagen Type I / Q000494:pharmacology*; D004195:Disease Models, Animal; D005260:Female; D005269:Femur / Q000187:drug effects* / Q000503:physiopathology / Q000601:surgery; D006801:Humans; D016348:Osseointegration / Q000187:drug effects* / Q000502:physiology; D011474:Prosthesis Design; D051381:Rats; D017207:Rats, Sprague-Dawley; D014025:Titanium
chemical_list: D020099:Coated Materials, Biocompatible; D024042:Collagen Type I; D014025:Titanium
keywords: Collagen type I; Implants; Osteointegration; Osteopenic condition