Miniscrew implant-supported maxillary canine retraction with and without corticotomy-facilitated orthodontics.

https://link.springer.com/content/pdf/10.1186%2F2196-1042-14-42.pdf

Acceleration of tooth movement during orthodontic treatment - a frontier in Orthodontics

Previous studies have shown that chronic dietary deficiency of calcium can result in more rapid orthodontic tooth movement. The purposes of this study were to confirm that finding in a calcium-deficient, lactating rat model and to quantify the degree to which the area of root surface resorption is affected by these conditions. Thirty-five adult female Sprague-Dawley rats were divided into two groups: (1) nonlactating animals on a control diet and (2) lactating animals on a calcium-deficient diet. A 60-gm orthodontic force designed to tip maxillary molars mesially was applied for varying times. At sacrifice, tooth movement was quantified by measuring the space created between maxillary molars; percent bone ash was measured for each humerus, and root surface resorption was estimated by means of a morphometric technique to measure the area of cratering on the mesial roots of first molars. Both groups showed a typical two-phased tooth movement cycle lasting for 10 days, although the magnitude of movement was significantly greater (p less than 0.001) in the test animals. The "humerus" test from animals exhibited a significantly decreased (p less than 0.001) fat-free dry weight, ash, and percent ash weight. The test group also displayed a significantly reduced percent area of root surface resorption (p less than 0.05) by 7 and 10 days following appliance activation. These findings confirm earlier observations that lactation, coupled with calcium deficiency, will produce decreased bone density which is consistent with increased parathyroid hormone secretion.(ABSTRACT TRUNCATED AT 250 WORDS)

Root resorption and tooth movement in orthodontically treated calcium deficient and lactating rats

Comparison of corticotomy-facilitated vs standard tooth-movement techniques in dogs with miniscrews as anchor units

Glioblastoma-Associated Microglia Reprogramming Is Mediated by Functional Transfer of Extracellular miR-21

Rapid orthodontic tooth movement aided by alveolar surgery in beagles

Objective: To evaluate, using multislice computed tomography (MSCT), the morphologic changes in the upper airway after large incisor retraction in adult bimaxillary protrusion patients. Materials and Methods: Thirty adult patients with bimaxillary protrusion had four first premolars extracted, and then miniscrews were placed to provide anchorage. A CT scan was performed before incisor retraction and again posttreatment. Three-dimensional (3D) reconstruction of the pre- (T1) and post- (T2) CT data was used to assess for morphological changes of the upper airway. A paired t-test was used to compare changes from T1 to T2. The relationship among the three variables (upper incisor retraction amount, upper airway size, and hyoid position) was analyzed by Pearson correlation coefficient. Results: The amounts of upper incisor retraction at the incisal edge and apex were 7.64 6 1.68 mm and 3.91 6 2.10 mm, respectively. The hyoid was retracted 2.96 6 0.54 mm and 9.87 6 2.92 mm, respectively, in the horizontal and vertical directions. No significant difference was observed in the mean cross-sectional area of the nasopharynx (P . .05) between T1 and T2, while significant differences between T1 and T2 were found in the mean cross-sectional areas of the palatopharynx, glossopharynx, and hypopharynx (P , .05); these mean cross-sectional areas were decreased by 21.02% 6 7.89%, 25.18% 6 13.51%, and 38.19% 6 5.51%, respectively. The largest change in the cross-sectional area is always noted in the hypopharynx. There was a significant correlation among the retraction distance of the upper incisor at its edge, the retraction distance of the hyoid in the horizontal direction, and the decrease of the hypopharynx. Conclusion: Large incisor retraction leads to narrowing of the upper airway in adult bimaxillary protrusion patients. (Angle Orthod. 2012;82:964–970.)

/pdf/effect-of-large-incisor-retraction-on-upper-airway-53watbzc71.pdf

Effect of large incisor retraction on upper airway morphology in adult bimaxillary protrusion patients

Human periodontal ligament stem cells (hPDLSCs) are mesenchymal stem cells (MSCs) derived from dental and craniofacial tissues that exhibit high potential for differentiation into osteoblasts. Recently, microRNAs (miRNAs) have been established to play important roles in MSC osteogenesis. In the current study, we report that miR-21 was down-regulated in osteogenically differentiated PDLSCs. Overexpression of miR-21 significantly inhibited osteogenesis of hPDLSC, whereas its inhibition demonstrated the opposite effects. Furthermore, SMAD family member 5 (Smad5) was predicted to be a downstream target of miR-21 and was shown to undergo up-regulation in PDLSCs induced toward osteogenesis. Moreover, Smad5 and Runx2, which are the critical transcription factors in osteogenic differentiation, were predicted to be targets of miR-21. Suppression of miR-21 expression increased the level of Smad5 in vitro and during in vivo transplantation experiments. Furthermore, suppression of Smad5 inhibited osteogenic differentiation and decreased the protein level of Runx2. Taken together, these results suggested that miR-21 be mechanistically implicated in the regulation of osteogenic differentiation of hPDLSCs by targeting Smad5.

/pdf/microrna-21-regulates-osteogenic-differentiation-of-1n6kgzcg9p.pdf

Tao Lv

Papers

Rapid orthodontic tooth movement aided by alveolar surgery in beagles

Effect of large incisor retraction on upper airway morphology in adult bimaxillary protrusion patients

MicroRNA-21 regulates Osteogenic Differentiation of Periodontal Ligament Stem Cells by targeting Smad5.

Drift characteristics of miniscrews and molars for anchorage under orthodontic force: 3-dimensional computed tomography registration evaluation

Biologic response of rapid tooth movement with periodontal ligament distraction