[Effects of micro-arc oxidation on the biological behaviors of MC3T3-E1 cells on titanium].

PURPOSE: This study was intended to modify the surface of pure titanium by micro-arc oxidation (MAO), and to investigate the effects of MAO process on the biological behavior of MC3T3-E1 osteoblastic cells. METHODS: MAO treatment of specimens were carried out using a staggered voltage boost procedure. The surface topography of the prepared specimens were observed by field emission scanning electron microscopy. Contact angle measurements were tested on a contact angle measuring system. MC3T3-E1 cells were cultured on specimens and the number of adhesion cells at 60 and 120 min were investigated by MTT. After 4 h of culture, cytoskeleton of the attached cells were examined using laser confocal scanning microscope. After 24, 72, 120 and 168 h of post seeding, cell proliferation were assessed using MTT assay. On day 16 of culture, the expressions of osteogenesis-related genes were analyzed through real time fluorescence quantitative polymerase chain reaction (qPCR). The data was analyzed using SPSS 16.0 software package. RESULTS: A porous oxide layer was grown on pure titanium substrates via MAO process. The contact angles for water and glycerol on the MAO surface were smaller than polished surface. At 2 culture times, the MAO surface showed significantly higher cell adhesion than polished surface. Actin staining indicated that the cells spread well on the MAO surface. At 72, 120 and 168 h, better cell proliferation were seen for MAO surfaces compared with that on the polished surface, but there was no significant difference. The qPCR showed that no obvious variations in gene expression of RUNX2 and ALP by MC3T3-E1 cells were observed on 2 different surfaces. CONCLUSIONS: Compared with polished surface, better adhesion of MC3T3-E1 cells are observed on MAO surface. However, no obvious change in gene expression of RUNX2 and ALP were observed between the MAO surface and polished surface.

[Treatment effects of the maxillary protraction in correction of maxillary deficiency: a comparative study between RPE group and no RPE group.].

PURPOSE: To compare the clinical effects of rapid palatal expansions combined with maxillary protractions to that of maxillary protractions of the maxillary deficiency alone. METHODS: Twenty patients aging from 9 to 11 years were divided into two groups , each group had 10 patients. All patients were diagnosed as having deficient maxillas with anterior crossbite. Group A were treated with rapid palatal expansion before maxillary protraction.Group B were treated with maxillary protraction alone. Lateral cephalometric films were taken at the beginning and the end of the treatment, and analyzed with McNamara analysis (Co-A,Co-Gn,ANS-Me) and traditional analysis. RESULTS: (1) After maxillary protraction,the maxilla and upper dentitions were protracted in both groups,the anterior crossbite had been corrected and obvious profile changes can be observed. (2) The mandible moved backward and downward in the RPE group and more obvious profile changes can be achieved compared with no RPE group. CONCLUSION: (1) It's an effective method to manage the maxillary deficiency with maxillary protraction in the mixed dentition. (2) Applying maxillary protraction combined with RPE is more adaptable to low angle cases.