[Preliminary clinical application of Chinese-made invisible orthodontic technique].

OBJECTIVE: To treat simple malocclusions preliminarily using Chinese-made invisible orthodontic aligners and discuss the indications, problems existed and future development. METHODS: Forty-one cases with different malocclusions were selected, including crowding, spaces and spaces due to periodontal problems. Invisible aligners were made and worn by patients and they were changed every 2 - 3 weeks. RESULTS: Acceptable treatment results were obtained in all cases, with nice alignments and good overbite and overjet. Treatment time ranged from 6 - 25 months. CONCLUSIONS: Indications of this technique were still limited and the technique needed to be further developed in the future.

[Effects of collagen I coating on the porous poly-lactide-co-glycolid on adhesion, proliferation, and differentiation of mesenchymal stem cells].

OBJECTIVE: To investigate the effects of collagen I on the adhesion, proliferation, and differentiation of MSCs on PLGA. METHODS: Collagen I was added onto the surface of pores in pieces of 3-D porous poly-lactide-co-glycolid (PLGA). Bone marrow-derived mesenchymal stem cells (MSCs) were obtained from New Zealand rabbits and were cultured for 3 generations, inoculated into the pores of PLGA pieces with the volume of 0.3 cm x 1.2 cm x 2.0 cm, and then cultured in solution with [(3)H]-thymidine deoxyribose (TdR). PLGA pieces not coated by collagen I were used as controls. The incorporation rate of [(3)H]-TdR was detected 2, 4, 6, and 8 hours, and 7, 14, and 21 days after culture, shown in count per minute (CPM) value, to determine the adhesion and proliferation of the MSCs. RT-POCR was used to examine the expressions of mRNA of the osteoblast markers: osteocalcin (OCN), alkaline phosphatase (ALP), and osteopontin (OPN). Scanning electron microscopy (SEM) was used to observe the morphology of MSCs. RESULTS: The CPM value since 6 hours after culture between the experimental group and control group began to be significantly different (both P < 0.05) The CPM values 7, 14, and 21 days after culture between the experimental group and control groups (P < 0.05 or P < 0.01). OCN, ALP, and OPN mRNA were expressed in MSCs of the experimental group and only ALP mRNA was weakly expressed in the control group. SEM showed the distribution of spindle and polygonal cells in the pores of the 3-D PLGA pieces and distribution of cylindrical or round cells in the control group. CONCLUSION: Collagen I is effective in promoting the adhesion, proliferation, and differentiation of MSCs on PLGA.