BACKGROUND: Trabecular metal has been reported to provide enough physiologic support for new bone formation, to induce bone ingrowth and osseointegration so as to achieve the biological synosteosis; therefore, it is available for improving the initial and second stability of the dental implant.OBJECTIVE: To explore the stress distributional differences between porous tantalum trabecular metal (PTTM) dental implant and conventional titanium (TI) dental implant in the zone of mandibular premolar using three-dimensional finite element analysis.METHODS: Three-dimensional finite element models emulating PTTM and TI dental implants were established using Mimics16.0 and CATIA in the zone of mandibular premolar with three types of bone (II, III, IV). Then 100 N force was applied on the abutment at a 45° angle to the vertical axis of the implants in software of MSC Patran2010 and Nastran2010, then the representative von Mises stress nodes were calculated and sampled randomly, and finally the von Mises stress distributional differences between two types of implants were analyzed using SPSS 20.0 statistical software.RESULTS AND CONCLUSION: (1) The Von Mises stresses around the two types of implants both focused on the interface of the cortical bone-abutment-implant region, and the stress was relatively less for the corresponding trabecular bone. (2) If the bone quality was similar, the average von Mises stress of PTTM was higher than that of TI dental implants, but there was no significant difference (P > 0.05). As the bone density lowered (II-IV), the average Von Mises stresses were both increased, and the increasing rate of PTTM was higher than that of TI in bone of II-III, and was lower than that of TI in bone of III-IV. In this experiment, there were no significant stress distributional differences between PTTM and TI dental implant. However, with the bone density reduction, the increasing rate of average Von Mises stress for PTTM was lowered than that for TI dental implants in bone of III-IV, which suggests that PTTM dental implant may be more beneficial for the primary and secondary stability in osteoporosis patients undergoing dental implantation.

Objcetive: To explore the treatment of long segment defect of tibia by using tensor fascia lata combined with iliac flap or deep circumflex iliac pedicle iliac flap. Methods: From February 2012 to August 2017, The People′s Hospital of Zun Yi City Bo Zhou District treated 16 patients who had long segment defect of tibia.There were 11 males and 5 females, age from 22 to 58 years old, the average age was 42 years old. Iliac flap grafting with tensor fascia lata combined with iliac flap or deep circumflex iliac pedicle was used to treat the defect of long segment of tibia. There were 4 cases with simple tibial defect and 12 cases with skin defect. The longest tibial defect was 5-8 cm. Results: In this study, four patients used iliac flaps with deep circumflex iliac pedicle, the area of flaps ranged from 2.5 cm×5.0 cm to 5.0 cm×10.0 cm, while the area of iliac flaps ranged from 5.0 cm×2.5 cm to 8.0 cm×4.0 cm. Twelve patients used grafting with tensor fascia lata combined with iliac flap, the area of flaps ranged from 5.0 cm×12.0 cm to 12.0 cm×23.0 cm, while the area of iliac flaps ranged from 7.0 cm×2.0 cm to 8.0 cm×4.0 cm. All 16 cases of bone flap were survived, fracture healing, without surgical complications. The average follow-up period was 1.5 years, the flaps had good appearance in 10 cases and was slightly bloated in 6 cases; the ankle had normal motion in 14 cases and had poor dorsal extension in 2 cases. X-ray films showed that the bone flap repaired the bone defects and reached bone healing. Conclusions Vascularized tensor fascia lata combined with iliac flap or deep circumflex iliac pedicle iliac flap grafts increase local blood supply and accelerate the process of fracture healing.