Effects of low-frequency ultrasound treatment of titanium surface roughness on osteoblast phenotype and maturation.
OBJECTIVE
Low-frequency ultrasound is widely used in the treatment of chronically infected wounds. To investigate its feasibility as a method for in situ restoration of metal implant surfaces in cases of peri-implantitis, we evaluated how low-frequency ultrasound affected surface properties of and response of human osteoblast-like MG63 cells to titanium (Ti).


METHODS
Three Ti surfaces [hydrophobic/smooth (pretreatment, PT); hydrophobic/rough (sandblasted/acid-etched, SLA); and hydrophilic/rough (SLA processed and stored hydrophilicity, mSLA)] were subjected to 25 kHz ultrasound for 10 min/cm2. Substrate roughness, chemical composition, and wettability were analyzed before and after ultrasound application. Osteoblastic maturation of cells on sonicated disks was compared to cells on untreated disks.


RESULTS
Ultrasound treatment altered the topography of all surfaces. Contact angles were reduced, and chemical compositions were altered by ultrasound on PT and SLA surfaces. Cell response to sonicated PT was comparable to untreated PT. Alkaline phosphatase was increased on sonicated SLA compared to untreated SLA, whereas DNA, osteocalcin, BMP2, osteoprotegerin, and VEGF-A were unchanged. Cells produced less osteocalcin and BMP2 on sonicated mSLA than on untreated mSLA, but no other parameters were affected.


CONCLUSIONS
These results show that low-frequency ultrasound altered Ti surface properties. Osteoblasts were sensitive to the changes induced by ultrasound treatment. The data suggest that the effect is to delay differentiation, but it is unclear whether this delay will prevent osseointegration. These results suggest that low-frequency ultrasound may be useful for treating implant surfaces in situ leading to successful re-osseointegration of implants affected by peri-implantitis.
Department of Orthopaedic Surgery, Otto-von-Guericke-Universität, Magdeburg, Germany.
Janina
J
Sedlaczek
Department of Orthopaedic Surgery, Otto-von-Guericke-Universität, Magdeburg, Germany.
Christoph H
CH
Lohmann
Department of Biomedical Engineering, School of Engineering, Virginia Commonwealth University, Richmond, VA, USA.
Ethan M
EM
Lotz
Department of Biomedical Engineering, School of Engineering, Virginia Commonwealth University, Richmond, VA, USA.
Sharon L
SL
Hyzy
Department of Biomedical Engineering, School of Engineering, Virginia Commonwealth University, Richmond, VA, USA.|Wallace H. Coulter Department of Biomedical Engineering, Georgia Institute of Technology, Atlanta, GA, USA.
Barbara D
BD
Boyan
Department of Biomedical Engineering, School of Engineering, Virginia Commonwealth University, Richmond, VA, USA.|Department of Periodontics, University of Texas Health Science Center at San Antonio, San Antonio, TX, USA.
Zvi
Z
Schwartz
D002478:Cells, Cultured; D006801:Humans; D010006:Osteoblasts / Q000502:physiology*; D010641:Phenotype; D013499:Surface Properties; D014025:Titanium; D014463:Ultrasonography / Q000379:methods
D014025:Titanium
peri-implantitis; periodontitis; titanium implant surface characterization; ultrasound