Objective To introduce the current development of periodontal regeneration. Methods The recent l iterature about advances in the regeneration of periodontium using tissue engineering was extensively reviewed and new technologies that will lead to further advances in periodontal therapy was investigated. Results The cells, appropriate signals,scaffold and blood supply play fundamental roles in periodontal regeneration. Furthermore, interreaction of these factors, such as cells modified by growth factor gene or growth factor del ivered by scaffold, will enhance their effects in tissue regeneration. Conclusion Periodontal tissue engineering have great potential and promising future in periodontal regeneration and therapy.
Objective To study the cl inical outcomes of Numelock II polyaxial system in treatment of type C fractures of the distal radius. Methods From March 2006 to June 2007, 12 cases of type C distal radial fractures (6 males and 6 females)were treated with open reduction and internal fixation. The mean age of the patients was 48.2 years (34-64 years)．The locations were left wrist in 5 cases and right wrist in 7 cases, including 1 case of old fracture and 11 cases of fresh fractures. All fractures were closed. The mean course of disease was 9 days and 7 hours (4 hours to 60 days). According to AO/ASIF classification, there were 4 cases of C1 type, 5 cases of C2 type and 3 cases of C3 type. Preoperatively, the palmar tilt angle was —30° to 30° (— 5° on average), and the radial inclination angle was 5° to 13° (7.7° on average), and the radial shortening was 5 mm to 15 mm (9 mm on average). One case combined with dislocation of elbow joint and 2 cases combined with multi ple injuries. Results All incision healed by first intention. Postoperative follow-up ranged from 14 months to 29 months (15.6 months on average). The X-ray films showed that the union of fractures was achieved 6-8 weeks (6.6 weeks on average). No screws breakage occurred. The articular facets weresmooth in 11 of 12 patients. After operation, the palmar tilt angle was 0° to 15° (6.7° on average), and the radial inclination angle was 5° to 15° (10.2° on average), showing significant differences when compared with those before operation (P lt; 0.05). All the radial shortening was corrected. The ROM of the wrist was 55%-100% of the normal side. The grip strength was 55%-90% of the normal side. The results were excellent in 9 cases, good in 2 cases, and poor in 1 cases by X-ray film and wrist function assessment, the excellent and good rate was 91.7%. Conclusion Numelock II polyaxial system fixation is an ideal method to treat type C fractures of the distal radius. Numelock II polyaxial mechanism may provide the free adjustabil ity of screw trajectories and a higher degree of overall stabil ity compared to monoaxial locking plates.