The effect of undersizing and tapping on bone to implant contact and implant primary stability: A histomorphometric study on bovine ribs

PURPOSE: Implant site preparation may be adjusted to achieve the maximum possible primary stability. The aim of this investigation was to study the relation among bone-to-implant contact at insertion, bone density, and implant primary stability intra-operatively measured by a torque-measuring implant motor, when implant sites were undersized or tapped. MATERIALS AND METHODS: Undersized (n=14), standard (n=13), and tapped (n=13) implant sites were prepared on 9 segments of bovine ribs. After measuring bone density using the implant motor, 40 implants were placed, and their primary stability assessed by measuring the integral of the torque-depth insertion curve. Bovine ribs were then processed histologically, the bone-to-implant contact measured and statistically correlated to bone density and the integral. RESULTS: Bone-to-implant contact and the integral of the torque-depth curve were significantly greater for undersized sites than tapped sites. Moreover, a correlation between bone to implant contact, the integral and bone density was found under all preparation conditions. The slope of the bone-to-implant/density and integral/density lines was significantly greater for undersized sites, while those corresponding to standard prepared and tapped sites did not differ significantly. CONCLUSION: The integral of the torque-depth curve provided reliable information about bone-to-implant contact and primary implant stability even in tapped or undersized sites. The linear relations found among the parameters suggests a connection between extent and modality of undersizing and the corresponding increase of the integral and, consequently, of primary stability. These results might help the physician determine the extent of undersizing needed to achieve the proper implant primary stability, according to the planned loading protocol.

Discussion on installation scheme of 3.0T high field magnetic resonance equipment in hospital / 中国医学装备

Objective: With the clinical application and popularization of magnetic resonance equipment, the installed amount of 3.0T high field magnetic resonance in the hospital was gradually increasing. This paper summarized the various technical factors involved in the installation of 3.0T high field MRI, and provided scientific and valuable reference for the installation and management of high field magnetic resonance equipment. Methods: During the installed process of GE discovery 3.0T magnetic resonance, to explore the correlative relationship among series of preparation work about installation of magnetic resonance, such as the selection of machine room, civil construction, shield construction and related electrical facilities and so on, and complete the connecting work among them. Results: Finally, the hospital has successfully completed machine room preparation for the 3.0T magnetic resonance, and has provided site guarantee for obtaining high-quality magnetic resonance images. Conclusion: In view of the special, importance and higher requirement for machine room of the magnetic resonance equipment, the seriously research and analysis should be applied and a coordinated mechanism of various type work should be established before the equipment is installed. During the construction process of machine room, enough consideration for detail in every aspect can provide guarantee for completing high-quality construction during the scheduled period, and achieve a satisfying effect.