Comparison of stainless steel and titanium alloy orthodontic miniscrew implants: a mechanical and histologic analysis.
BACKGROUND
The detailed mechanical and histologic properties of stainless steel miniscrew implants used for temporary orthodontic anchorage have not been assessed. Thus, the purpose of this study was to compare them with identically sized titanium alloy miniscrew implants.


METHODS
Forty-eight stainless steel and 48 titanium alloy miniscrew implants were inserted into the tibias of 12 rabbits. Insertion torque and primary stability were recorded. One hundred grams of tensile force was applied between half of the implants in each group, resulting in 4 subgroups of 24 specimens each. Fluorochrome labeling was administered at weeks 4 and 5. When the rabbits were euthanized at 6 weeks, stability and removal torque were measured in half (ie, 12 specimens) of each of the 4 subgroups. Microdamage burden and bone-to-implant contact ratio were quantified in the other 12 specimens in each subgroup. Mixed model analysis of variance was used for statistical analysis.


RESULTS
All implants were stable at insertion and after 6 weeks. The only significant difference was the higher (9%) insertion torque for stainless steel. No significant differences were found between stainless steel and titanium alloy miniscrew implants in microdamage burden and bone-to-implant contact regardless of loading status.


CONCLUSIONS
Stainless steel and titanium alloy miniscrew implants provide the same mechanical stability and similar histologic responses, suggesting that both are suitable for immediate orthodontic clinical loads.
Former resident, Department of Orthodontics and Oral Facial Genetics, Indiana University School of Dentistry, Indiana University-Purdue University, Indianapolis, Ind.
Ryan N
RN
Brown
Former resident, Department of Orthodontics and Oral Facial Genetics, Indiana University School of Dentistry, Indiana University-Purdue University, Indianapolis, Ind.
Brent E
BE
Sexton
Associate professor, Department of Restorative Dentistry, Division of Dental Biomaterials, Indiana University School of Dentistry, Indiana University-Purdue University, Indianapolis, Ind.
Tien-Min
TM
Gabriel Chu
Associate professor, Department of Orthodontics and Oral Facial Genetics, School of Dentistry, Indiana University-Purdue University, Indianapolis, Ind; associate professor, Department of Mechanical Engineering, School of Engineering and Technology, Indiana University-Purdue University, Indianapolis, Ind.
Thomas R
TR
Katona
Assistant professor, Department of Orthodontics and Oral Facial Genetics, Indiana University School of Dentistry, Indiana University-Purdue University, Indianapolis, Ind.
Kelton T
KT
Stewart
Professor and chair, Department of Orthodontics, School of Dentistry, Kyungpook National University, Daegu, Korea.
Hee-Moon
HM
Kyung
Assistant professor, Department of Orthodontics and Oral Facial Genetics, Indiana University School of Dentistry, Indiana University-Purdue University, Indianapolis, Ind. Electronic address: ssliu@iu.edu.
Sean Shih-Yao
SS
Liu
D000497:Alloys; D000818:Animals; D001696:Biomechanical Phenomena; D016723:Bone Remodeling / Q000502:physiology; D003722:Dental Alloys / Q000737:chemistry*; D015921:Dental Implants; D005456:Fluorescent Dyes; D008297:Male; D052280:Orthodontic Anchorage Procedures / Q000295:instrumentation*; D016382:Orthodontic Appliance Design; D009969:Orthodontic Wires; D016348:Osseointegration / Q000502:physiology; D011817:Rabbits; D012394:Rosaniline Dyes; D013193:Stainless Steel / Q000737:chemistry*; D013314:Stress, Mechanical; D013499:Surface Properties; D013977:Tibia / Q000473:pathology / Q000601:surgery; D014025:Titanium / Q000737:chemistry*; D019415:Torque
D000497:Alloys; D003722:Dental Alloys; D015921:Dental Implants; D005456:Fluorescent Dyes; D012394:Rosaniline Dyes; D013193:Stainless Steel; C031462:titanium alloy (TiAl6V4); C025485:basic fuchsin; D014025:Titanium