Micro-implant anchorage was used for orthodontic intervention of 3 patients with buccal impacted maxillary canine,good clinical outcome was obtained.The micro-implant anchorage may provided a new approach for the treatment of this kind of teeth.

Objective : To discuss the effectiveness and mechanism for movement of maxillary buccally transposed canines by using a door-shaped individualized dental archwire mechanic and to provide a reference for clinicians. Methods: Eight patients with unilateral maxillary transposed canines were enrolled. All patients were treated with door-shaped individualized archwires. Before treatment (T1) and after the crowns of the transposed canines were moved to the right buccal positions in the dental arch during the treatment (T2), orthopantomograms were taken both at T1 and T2 to compare the linear changes (distance changes of the crown and root apex) and angular changes to study the mechanisms of tooth movement. The probing depth and buccal crown height were measured using a periodontal probe to compare periodontal changes before treatment (T1) and after treatment (T3) between the transposed canines and contralateral canines. Results: All eight transposed canines were successfully brought back to their normal dental arch position but were made more buccal by using the door-shaped individualized dental archwire, with a mean of (11.5 ± 2.7) months. The average overall duration was (28.3 ± 4.7) months. The crown distance changes of the canines from T1 to T2 (8.1 mm) were greater than those of the root apexes (1.5 mm) (P<0.05). The mean angulation changes of the long axes of the canines were 17.5°. There was no significant difference in the depth of periodontal measurement and buccal crown height measurement between T1 and T3 (P>0.05). Conclusion The buccal movement of maxillary transposed canines under a door-shaped individualized dental archwire was effective and feasible. The movement pattern under this mechanism was controlled tipping.

Objective: To compare the osteogenic differentiation abilities of human bone marrow mesenchymal stem cells (hBMSCs) from different sources, and to provide basis for choosing a new source of seed cells in bone tissue engineering. Methods: Jaw bone-marrow-derived mesenchymal stem cells (JMMSCs) were isolated from orthognathic surgical sites and cultured by limited dilution for single cell clone. Long bone-marrow-derived mesenchymal stem cells (BMMSCs) were obtained from bone marrow of volunteers and isolated by density gradient centrifugation method. Flow cytometry was used to detect the surface markers of both cells. Osteogenic ability was assessed by PCR and Western Blot after osteogenic differentiation for the following molecules: Runx2, COL-1 and OCN. Alizarin red staining was used for determining the ability of cell mineralization after osteogenic differentiation. Results : The expressions of cell surface markers CD90 and CD105 were positive in both type of cells, while CD34, CD14 and CD45 were all negative. After 21 days of osteogenic induction, JMMSCs formed significantly more mineralized nodules than BMMSCs. After 7, 14, 21 days of osteogenic induction, JMMSCs expressed more osteogenic-related molecules than BMMSCs. Conclusion The osteogenic differentiation capacity and mineralization ability of JMMSCs are significantly higher than BMMSCs. Jaw bone might be a more suitable source of seed cells in bone tissue engineering compared with long bone.

OBJECTIVE: This study aims to investigate the mechanism of K (lysine) acetyltransferase 2A (KAT2A) regulation and control on the osteogenic differentiation of periodontal ligament stem cells (PDLSCs). METHODS: The expression levels of KAT2A in PDLSCs were compared from each generation of the normal (H-PDLSCs) and periodontitis tissues (P-PDLSCs). The influences of KAT2A gene interference on the osteogenic differentiation of PDLSCs were also detected. In addition, the influences of the KAT2A gene interference to the canonical Wnt pathway and ligands were detected. The upstream and down-stream relationships between KAT2A and canonical Wnt pathway were also determined. RESULTS: The decreased expression of KAT2A in PDLSCs from the inflammatory tissue in each generation was compared with that in PDLSCs from the healthy tissue, and the difference was statistically significant (P<0.05). When the KAT2A gene was disrupted, the osteogenesis ability of PDLSC was declined, and the difference was statistically significant (P<0.05). The canonical Wnt pathway was activated, and the antagonist Dickkopf-1 (DKK-1) was reduced. After the DKK-1 addition, the osteogenic differentiation of the disturbed PDLSCs was recovered, and KAT2A was unaffected. CONCLUSIONS The KAT2A expression in PDLSCs was decreased because of perio-dontitis. The classical Wnt pathway was activated to inhibit the osteogenic differentiation of the cells.
Acetyltransferases ; Cell Differentiation ; Cells, Cultured ; Histone Acetyltransferases ; metabolism ; Humans ; Lysine ; Osteogenesis ; Periodontal Ligament ; metabolism ; Periodontitis ; metabolism ; Stem Cells ; Wnt Signaling Pathway