[Clinical study on early loading restoration of superhydrophilic implants].

Objective: To study the clinical effect of early loading restoration a superhydrophilic implant after 1 year, so as to provide reference evidence for clinical practice. Methods: A total of 41 patients with dental defects, including 20 males and 21 females [age (52.3±13.1) years old], were enrolled in the Department of VIP, Hangzhou Dental Hospital (Pinghai Hospital) from July 2017 to January 2019. A total of 74 superhydrophilic implants were implanted, including 27 maxillary implants and 47 mandiolar implants. All patients without bone augmentation or soft tissue transplantation, the maxilla was taken impression 4 weeks after implant implantation, with 6 weeks of loading, the mandible was taken impression 2 weeks after implant implantation, with 4 weeks of loading. The stability of the implant was measured by resonance frequency analyzer before implant implantation, impression and loading. Periapical radiograph were taken immediately after mold removal, immediately after loading and reexamination 1 year after loading, to measure and record the changes in the bone level of the mesial and distal margins of the implant. Results: No biological complications occurred in all implants before loading restoration, and the implant survival rate was 100%(74/74). In 2 cases, the implant stability quotient (ISQ) value of the implant at the mandibular site was lower than 65 at 2 weeks after surgery, and the restoration was delayed. The ISQ values of the other 72 implants at the time of implantation (75.22±4.32) were not significantly different from those at the time of modeling (75.13±4.23) (P>0.05), but the ISQ values at the moment of weight loading (76.46±3.73) were significantly higher than those at modeling (P<0.05). All the early loading implants were reviewed 1 year after early loading, and none of them were loose or fell off, and the implant survival rate was 100%(72/72). X-ray measurement and evaluation showed that after 1 year of early loading restoration, the mean marginal bone absorption of 72 implants was (0.18±0.06) mm, among which the mandibular was (0.17±0.06) mm and the maxillary was (0.19±0.06) mm, showing no statistical difference (P>0.05). After 1 year of early loading restoration, the mean marginal bone absorption of 72 implants was (0.17±0.05) mm, including (0.17±0.06) mm for mandibular and (0.16±0.05) mm for maxillary, showing no statistical difference (P>0.05). Conclusions: In the limited scope of this clinical study, it has been proved that early loading of superhydrophilic implant is a safe and feasible treatment scheme, and the bone resorption at the implant edge after long-term early loading restoration needs further follow-up study.

[Advance in study of artificial nerve].

OBJECTIVE: To review the advance in materials of nerve conduit and Schwann cell transplantation for preparation of artificial nerve with tissue engineering technique. METHODS: Recent literatures about artificial nerve, nerve conduit and Schwann cell transplantation were extensively reviewed. RESULTS: Many biomaterials such as silicon, dacron, expanded polytetrafluoroethylene(ePTFE), polyester and chitin could be used as nerve conduits to repair nerve defect, the degradable biomaterials were better. The nerve conduit with intrinsic filaments could be used to bridge an extended gap in peripheral nerve. Purified and cultured Schwann cells were still bioactive. Axonal regeneration could be enhanced after implantation of Schwann cells into nerve conduit. CONCLUSION: The ideal artificial nerve is composed of three dimensional biodegradable nerve conduit and bioactive Schwann cells, Schwann cells can be distributed in nerve conduit just like Bünger's band.