Modulated bone matrix-related gene expression is associated with differences in interfacial strength of different implant surface roughness.
OBJECTIVE
The objective of this study was to examine the effect of implant surface topography on biomechanical strength and expression patterns of bone extracellular matrix (ECM)-related genes during implant healing.


METHODS
Cylinder implants with turned or dual acid-etched (DE) surface were placed into the femurs of female Sprague-Dawley rats. At 2 and 4 weeks after the implantation, the implant push-in test was performed to measure the load-bearing strength of the bone-tissue interface. T-shaped hollow implants were separately placed and the total RNA was extracted from the ingrown tissue within the hollow chamber. The RNA was subjected to reverse transcriptase polymerase chain reaction to analyze the expression pattern of selected bone extracellular matrix-related genes.


RESULTS
The push-in value of the DE implant is approximately 300% greater than that of the turned implant at weeks 2 and 4 (p=.0090). The expression of collagen II, osteocalcin and biglycan was higher in the week 2 DE implant group than the turned implant group. At week 4 the expression of collagen II and IX was 7- and 26-fold, respectively, greater in the DE implant group than in the turned implant group.


CONCLUSIONS
The surface topography of implants may induce the phenotypic alteration of wound healing cells. The increased interfacial strength of the DE implant may be associated with the modulated expression of the selected set of bone extracellular matrix genes.
Ogawa
Takahiro
T
Jane and Jerry Weintraub Center for Reconstructive Biotechnology, Division of Advanced Prosthodontics, Biomaterials and Hospital Dentistry, UCLA School of Dentistry, Los Angeles, CA 90095, USA.
Sukotjo
Cortino
C
Nishimura
Ichiro
I
D000134:Acid Etching, Dental; D000704:Analysis of Variance; D000818:Animals; D058578:Biglycan; D001857:Bone Matrix / Q000378:metabolism*; D024043:Collagen Type II / Q000235:genetics; D024081:Collagen Type IX / Q000235:genetics; D015921:Dental Implants; D017267:Dental Prosthesis Design; D005109:Extracellular Matrix / Q000235:genetics; D016326:Extracellular Matrix Proteins / Q000235:genetics; D005260:Female; D005786:Gene Expression Regulation / Q000235:genetics*; D016348:Osseointegration; D015675:Osteocalcin / Q000235:genetics; D010641:Phenotype; D011509:Proteoglycans / Q000235:genetics; D012313:RNA / Q000235:genetics; D051381:Rats; D017207:Rats, Sprague-Dawley; D020133:Reverse Transcriptase Polymerase Chain Reaction; D018709:Statistics, Nonparametric; D013314:Stress, Mechanical; D013499:Surface Properties; D016474:Weight-Bearing / Q000502:physiology; D014945:Wound Healing / Q000235:genetics
D058578:Biglycan; D024043:Collagen Type II; D024081:Collagen Type IX; D015921:Dental Implants; D016326:Extracellular Matrix Proteins; D011509:Proteoglycans; D015675:Osteocalcin; D012313:RNA