Biologic evaluation of a hollow-type miniscrew implant: an experimental study in beagles.
BACKGROUND
The aims of this study were to assess the biologic stability of a newly designed hollow (H-type) miniscrew compared with conventional (C-type) miniscrews through histomorphometric and histologic analysis.


METHODS
Both types of miniscrews were placed into the maxillae and the mandibles of 12 beagles. Maximum insertion torque, Periotest (Siemens AG, Bensheim, Germany) value, bone-implant contact, and bone volume were measured.


RESULTS
The overall success rates of the H-type were 78.3% in the maxilla and 60.0% in the mandible. Mean maximum insertion torque values of the H-type were 14.2 N-cm in the maxilla and 20.9 N-cm in the mandible. The Periotest values of the H-type were -1.5 in the maxilla and -6.4 in the mandible. Mean maximum insertion torque and Periotest values of the H-type were higher than those of the C-type. In the maxilla, the bone-implant contact values of the H-type were 37.3% and 32.3% at 3 and 12 weeks, respectively. In the mandible, the bone-implant contact values were 31.4% and 18.5% at 3 and 12 weeks, respectively.


CONCLUSIONS
Considering the lower success rate and the insufficient bone-implant contact and bone volume of the H-type in the mandible, the clinician should choose a suitable combination of miniscrews depending on local bone quality and implantation site, such as an H-type in the maxilla and a C-type in the mandible.
Private Practice, Seoul, Korea.
Jeong-Won
JW
Youn
Associate professor, Department of Orthodontics, College of Dentistry, Yonsei University, Seoul, Korea. Electronic address: hwang@yuhs.ac.
Jung-Yul
JY
Cha
Professor, Department of Orthodontics, College of Dentistry, Yonsei University, Seoul, Korea.
Hyung-Seog
HS
Yu
Professor, Department of Orthodontics, Institute of Craniofacial Deformity Center, College of Dentistry, Yonsei University, Seoul, Korea.
Chung-Ju
CJ
Hwang
D000818:Animals; D015519:Bone Density / Q000502:physiology; D016723:Bone Remodeling / Q000502:physiology; D001863:Bone Screws; D003238:Connective Tissue / Q000473:pathology; D004285:Dogs; D007091:Image Processing, Computer-Assisted / Q000379:methods; D008297:Male; D008334:Mandible / Q000473:pathology / Q000601:surgery; D008437:Maxilla / Q000473:pathology / Q000601:surgery; D008904:Miniaturization; D052280:Orthodontic Anchorage Procedures / Q000295:instrumentation*; D016382:Orthodontic Appliance Design; D016348:Osseointegration / Q000502:physiology; D010006:Osteoblasts / Q000473:pathology; D010012:Osteogenesis / Q000502:physiology; D013499:Surface Properties; D013997:Time Factors; D019415:Torque; D014732:Vibration