Bone response to unloaded titanium implants in the fibula, iliac crest, and scapula: an animal study in the Yorkshire pig

• Published in: International journal of oral and maxillofacial surgery 2003-08, Vol.32 (4), p.383-389
• Main Authors: Rohner, D., Meng, C.S., Hutmacher, D.W., Tsai, K.T.
• Format: Article
• Language: English
• Subjects: Animals; Biological and medical sciences; Biomechanical Phenomena; Bone and Bones - physiology; Bone and Bones - surgery; Dental Etching; Dental Implantation, Endosseous - methods; Dental Implants; Dental Prosthesis Design; Dentistry; Female; Fibula - physiology; free vascularized flaps; Head and neck surgery. Maxillofacial surgery. Dental surgery. Orthodontics; Ilium - physiology; interfacial strength; Maxillofacial surgery. Dental surgery. Orthodontics; Medical sciences; Osseointegration; prefabrication; removal torque; Scapula - physiology; Stress, Mechanical; Surface Properties; Surgery (general aspects). Transplantations, organ and tissue grafts. Graft diseases; Swine; Time Factors; Titanium - chemistry; titanium implants; Torque; Wound Healing
• ISSN: 0901-5027; 1399-0020
• DOI: 10.1054/ijom.2002.0367

The reconstruction of extended maxillary and mandibular defects with prefabricated free flaps is a two stage procedure, that allows immediate function with implant supported dentures. The appropriate delay between prefabrication and reconstruction depends on the interfacial strength of the bone–implant surface. The purpose of this animal study was to evaluate the removal torque of unloaded titanium implants in the fibula, the scapula and the iliac crest. Ninety implants with a sandblasted and acid-etched (SLA) surface were tested after healing periods of 3, 6, and 12 weeks, respectively. Removal torque values (RTV) were collected using a computerized counterclockwise torque driver. The bicortical anchored 8mm implants in the fibula revealed values of 63.73Ncm, 91.50Ncm, and 101.83Ncm at 3, 6, and 12 weeks, respectively. The monocortical anchorage in the iliac crest showed values of 71.40Ncm, 63.14Ncm, and 61.59Ncm with 12mm implants at the corresponding times. The monocortical anchorage in the scapula demonstrated mean RTV of 62.28Ncm, 97.63Ncm, and 99.7Ncm with 12mm implants at 3, 6, and 12 weeks, respectively. The study showed an increase of removal torque with increasing healing time. The interfacial strength for bicortical anchored 8mm implants in the fibula was comparable to monocortical anchored 12mm implants in the iliac crest and the scapula at the corresponding times. The resistance to shear seemed to be determined by the type of anchorage (monocortical vs. bicortical) and the length of the implant with greater amount of bone–implant interface.