PURPOSE: This study aimed to evaluate the effect of implant thread depth on primary stability in low density bone. MATERIALS AND METHODS: The insertion torque was measured by inserting Ti implants with different thread depths into solid rigid polyurethane blocks (Sawbones) with three different bone densities (0.16 g/cm3, 0.24 g/cm3, and 0.32 g/cm3). The insertion torque value was evaluated with a surgical engine. The static compressive strength was measured with a universal testing machine (UTM) and the Ti implants were aligned at 30degrees against the loading direction of the UTM. After the static compressive strength test, the Ti implants were analyzed with a Measurescope. RESULTS: The Ti implants with deeper thread depth showed statistically higher mean insertion torque values (P<.001). Groups A and group B had similar maximum static compressive strengths, as did groups C and D (P>.05). After the static compressive strength, the thread shape of the Ti implants with deeper thread depth did not show any breakage but did show deformation of the implant body and abutment. CONCLUSION: The implants with deeper thread depth had higher mean insertion torque values but not lower compressive strength. The deep threads had a mechanical stability. Implants with deeper thread depth may increase the primary stability in areas of poor quality bone without decreasing mechanical strength.
Bone Density ; Compressive Strength ; Dental Implants* ; Polyurethanes ; Torque

PURPOSE: This study aimed to evaluate the effect of implant thread depth on primary stability in low density bone. MATERIALS AND METHODS: The insertion torque was measured by inserting Ti implants with different thread depths into solid rigid polyurethane blocks (Sawbones) with three different bone densities (0.16 g/cm3, 0.24 g/cm3, and 0.32 g/cm3). The insertion torque value was evaluated with a surgical engine. The static compressive strength was measured with a universal testing machine (UTM) and the Ti implants were aligned at 30degrees against the loading direction of the UTM. After the static compressive strength test, the Ti implants were analyzed with a Measurescope. RESULTS: The Ti implants with deeper thread depth showed statistically higher mean insertion torque values (P<.001). Groups A and group B had similar maximum static compressive strengths, as did groups C and D (P>.05). After the static compressive strength, the thread shape of the Ti implants with deeper thread depth did not show any breakage but did show deformation of the implant body and abutment. CONCLUSION: The implants with deeper thread depth had higher mean insertion torque values but not lower compressive strength. The deep threads had a mechanical stability. Implants with deeper thread depth may increase the primary stability in areas of poor quality bone without decreasing mechanical strength.
Bone Density ; Compressive Strength ; Dental Implants* ; Polyurethanes ; Torque

Ionizing radiation has long been used in medicine since the discovery of X-rays. Diagnostic imaging using synchrotron radiation has been under investigation since Rubenstein et al. reported dual-energy iodine-K-edge subtraction coronary angiography. Recently, computed tomography (CT) and magnetic resonance imaging (MRI) have provided better quality results than conventional radiology, providing important information on human internal structures. However, such techniques are unable to detect fine micron sized structures for the early diagnosis of tumors, vascular diseases and other medical objectives. Third generation synchrotron X-rays are well known for their superiority in coherence and energy tunability with respect to conventional X-rays. Consequently, new contrast mechanisms with a superior spatial resolution are becoming available. Here we present the extremely fine details of live animal internal structures using unmonochromatized synchrotron X-rays (white beam) and a simple detector system. Natural movements of the internal organs are also shown. The results indicate that this imaging technique can be applied to investigating microstructures and evaluating the function of the internal organs. Furthermore, this imaging system may be applied to humans as the next tool beyond CT and MRI.
Animal ; *Diagnostic Imaging ; Male ; Mice ; Mice, Inbred HRS ; *Synchrotrons