Treating high angle bimaxillary protrusion with three kinds of extraction method: a clinical study / 华西口腔医学杂志

<p><b>OBJECTIVE</b>To compare the effect of three kinds of extraction model on high angle bimaxillary protrusion patients.</p><p><b>METHODS</b>A total of 30 patients with Class I malocclusion and bimaxillary protrusion, aged 14-25 years old, were selected and divided into three groups. Four first premolars were extracted in the first group. The two maxillary first premolars and two mandibular first molars were extracted in the second group. The two maxillary first premolars and two mandibular first molars were extracted in the third group, and two additional micro-implants used as orthodontic anchorage in maxilla. Three groups were all treated with MBT appliance. Cephalometric analysis were carried out before and after treatment, and the results were analyzed with statistics.</p><p><b>RESULTS</b>1) About the hard tissues, compared with the first group, there were statistically significant differences of N-Me, SGo/NMe, ANS-Me, FH/MP, SN/MP, and ODI in the second and the third group after treatment (P<0.01). 2) About the soft tissues, the teeth and the alveolar bone, compared with the first group, there were statistically significant differences of Pg-Pos, Li-SnPos, Si-LiPos, LL-E, L1-NB, L1/NB, U1/L1, L7-MP in the second and the third group after treatment (P<0.01). 3) All patients received consummate orthodontic treatment and obtained fine occlusion. Facial profiles were improved significantly after orthodontic treatment.</p><p><b>CONCLUSION</b>1) After orthodontic treatment with mandibular first molars extraction, FH/MP, SN/MP, N-Me, ANS-Me, L1-NB and L1/NB decreased respectively, and soft tissue profiles were improved significantly. 2) Additional micro-implant used as orthodontic anchorage in maxilla significantly contributed to the maxillary incisor retraction and subsequent soft tissue change. 3) The first molars extraction and additional micro-implant used as orthodontic anchorage are efficient in improving the facial profiles for high angle bimaxillary protrusion patients.</p>

The effect of Nifedipine and mechanical strain on matrix metalloproteinase expression in human periodontal ligament fibroblast / 华西口腔医学杂志

<p><b>OBJECTIVE</b>To investigate the effect of Nifedipine on matrix metalloproteinase (MMP)-10 and MMP-13 expression in human periodontal ligament fibroblast (HPDLF) induced by mechanical strain in vitro.</p><p><b>METHODS</b>HPDLF was divided into four groups at random by mechanical strain of elongation 0%, 8%, 12% and 16%. Each group was divided into four subgroups again by the concentration of Nifedipine 0, 10, 30, 50 microm. The cells were imposed to state mechanical strain 12 h after incubated with Nifedipine 1 h. And then immunohistochemical staining was used to investigate the expressions of MMP-10 and MMP-13 in intracytoplasm.</p><p><b>RESULTS</b>In 0% group, there was no significant difference of MMP-10 and MMP-13 expression in all subgroups (P>0.05). The expressions of MMP-10 and MMP-13 were high in group 8%, 12% and 16% without Nifedipine, and increasing significantly with elongation (P<0.001). The expressions of MMP-10 and MMP-13 decreased with dose increasing (P<0.001) in HPDLF after imposed to Nifidepine.</p><p><b>CONCLUSION</b>The expressions of MMP-10 and MMP-13 induced by mechanical strain were inhibited by Nifedipine, which suggested calcium ions channels participate in expressions of MMP-10 and MMP-13 induced by loading.</p>