title: Effects of phosphoric acid treatment of titanium surfaces on surface properties, osteoblast response and removal of torque forces.
abstract: This study investigated the surface characteristics and biocompatibility of phosphate ion (P)-incorporated titanium (Ti) surfaces hydrothermally treated with various concentrations of phosphoric acid (H(3)PO(4)). The surface characteristics were evaluated by scanning electron microscopy, thin-film X-ray diffractometry, X-ray photoelectron spectroscopy, optical profilometry, contact angle and surface energy measurement and inductively coupled plasma mass spectroscopy (ICP-MS). MC3T3-E1 cell attachment, spreading, proliferation and osteoblastic gene expression on different surfaces were evaluated. The degree of bony integration was biomechanically evaluated by removal torque testing after 4 weeks of healing in rabbit tibiae. The H(3)PO(4) treatment produced micro-rough Ti surfaces with crystalline P-incorporated Ti oxide layers. High concentration H(3)PO(4) treatment (1% and 2%) produced significantly higher hydrophilic surfaces compared with low H(3)PO(4) treatment (0.5%) and untreated surfaces (P<0.01). ICP-MS analysis showed P ions were released from P-incorporated surfaces. Significant increased cell attachment (P<0.05) and notably higher mRNA expressions of Runx2, alkaline phosphatase, osteopontin and osteocalcin were observed in cells grown on P-incorporated surfaces compared with cells on untreated machined surfaces. P-incorporated surfaces showed significantly higher removal torque forces compared with untreated machined implants (P<0.05). Ti surfaces treated with 2% H(3)PO(4) showed increasing tendencies in osteoblastic gene expression and removal torque forces compared with those treated with lower H(3)PO(4) concentrations or untreated surfaces. These results demonstrate that H(3)PO(4) treatment may improve the biocompatibility of Ti implants by enhancing osteoblast attachment, differentiation and biomechanical anchorage.
authors.affiliation: Department of Periodontology, School of Dentistry, Kyungpook National University, 188-1, Samduk 2Ga, Jung-Gu, Daegu 700-412, Republic of Korea. jinwoo@knu.ac.kr
authors.forename: Jin-Woo
authors.initials: JW
authors.lastname: Park
authors.forename: Youn-Jeong
authors.initials: YJ
authors.lastname: Kim
authors.forename: Je-Hee
authors.initials: JH
authors.lastname: Jang
authors.forename: Tae-Geon
authors.initials: TG
authors.lastname: Kwon
authors.forename: Yong-Chul
authors.initials: YC
authors.lastname: Bae
authors.forename: Jo-Young
authors.initials: JY
authors.lastname: Suh
mesh_terms: D000818:Animals; D001696:Biomechanical Phenomena / Q000187:drug effects; D002448:Cell Adhesion / Q000187:drug effects; D002452:Cell Count; D002460:Cell Line; D002465:Cell Movement / Q000187:drug effects; D049109:Cell Proliferation / Q000187:drug effects; D048430:Cell Shape / Q000187:drug effects; D005786:Gene Expression Regulation / Q000187:drug effects; D008297:Male; D051379:Mice; D008855:Microscopy, Electron, Scanning; D010006:Osteoblasts / Q000166:cytology* / Q000187:drug effects* / Q000378:metabolism / Q000648:ultrastructure; D010756:Phosphoric Acids / Q000494:pharmacology*; D056951:Photoelectron Spectroscopy; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D011817:Rabbits; D020133:Reverse Transcriptase Polymerase Chain Reaction; D013499:Surface Properties / Q000187:drug effects; D014025:Titanium / Q000494:pharmacology*; D019415:Torque; D014961:X-Ray Diffraction
chemical_list: D010756:Phosphoric Acids; D012333:RNA, Messenger; D014025:Titanium; C030242:phosphoric acid