The Expression of MMP—3 and TIMP—1 During Orthodontic Periodontium Remodeling in Rats

目的：观察大鼠正畸牙周组织改建过程中基质金属蛋白酶—3(MMP—3)和金属蛋白酶组织抑制因子—1(TIMP—1)表达的变化，探讨MMP—3及TIMP—1与正畸牙齿移动的关系。方法：在SD成年大鼠上颌右侧第一磨牙与上颌切牙之间安置正畸装置，建立大鼠磨牙移动实验模型。于牙齿移动1、3、5、7、14d后取材分别进行免疫组化染色、图像分析。结果：牙齿移动1d后，牙周组织细胞MMP—3表达增强，5d后MMP—3表达达到高峰，此时破骨细胞脑浆亦呈强阳性表达。以后MMP—3表达有所下降，但仍高于对照组。而TIMP—1于牙齿移动3d后表达开始增强，7d后显著表达。结论：MMP—3及TIMP—1参与了正畸牙周组织改建过程，MMP—3在破骨细胞性骨吸收中起着重要作用。     

固定正畸后牙根吸收的部分影响因素分析

目的　研究影响正畸治疗后牙根吸收的部分临床因素。方法　随机选择经过固定正畸治疗 ,有清晰可辨的矫治前后全口曲面断层片者 96例。以改良根吸收分级法评估每名患者矫治前后全口牙齿根吸收情况。通过多元方差分析及多元回归分析 ,探讨正畸后平均根吸收值 (rootresorptionaftertreatment ,RRAT )与性别、年龄、减数与否、部位、疗程和治疗前平均根吸收值 (rootresorptionbeforetreatment,RRBT )的关系。结果　①女性RRAT校正均值为 0 4 1,男性为 0 34,差异有高度显著性 (P <0 .0 5 )。②拔牙组的RRAT校正均值为 0 4 3,未拔牙组为 0 31,差异有高度显著性(P <0 .0 0 1)。③前牙区RRAT校正均值为 0 5 9,后牙区为 0 12 ,差异有高度显著性。④上牙RRAT校正均值为 0 4 0 ,下牙为 0 37,差异无显著性。⑤RRAT与年龄、疗程及RRBT呈正相关 ,复相关系数R =0 5 9,判定系数R2 =0 35。结论　性别、年龄、减数与否、疗程、部位及治疗前牙根状况对正畸治疗后牙根吸收均有影响。     

应用Micro-CT研究矫治力对正畸牙齿移动及牙根吸收的影响

目的：了解不同矫治力作用下大鼠牙齿移动距离及牙根吸收情况,探索应用Micro?CT研究正畸牙齿移动过程中矫治力对牙根吸收的影响。方法10周龄健康雄性SD大鼠64只（220~270 g）,分别施以10 g （10 g力组）、30 g力（130 g力组）拉右侧上颌第一磨牙向近中移动建立实验动物模型,以对侧同名牙为对照牙。于加力后第3、7、14、28天处死动物,使用Micro?CT扫描上颌第一磨牙及周围牙槽骨,测量上颌第一磨牙近中移动距离,计算加力28 d上颌第一磨牙近中根的表面凹陷体积,进行统计学分析。结果加力后发生牙齿移动,10 g力组在加力14 d内,牙齿移动量小于30 g力组（P =0.039）,在加力28 d时大于30 g力组（P<0.05）。加力28 d,10 g力组、30 g力组的牙根表面凹陷总体积高于对照组（P=0.004）,30 g力组产生的牙根表面凹陷总体积高于10 g力组（P<0.001）。结论 Micro?CT可以对牙齿移动及牙根吸收进行可靠评价及量化分析。加力后28 d,10 g力组移动量较30 g力组大,相应产生牙根吸收较30 g力组少。     

Phototherapy is unable to exert beneficial effects on orthodontic tooth movement in rat molars

Objectives:To investigate the effects of irradiation lasers and light-emitting diode (LED) light on root resorption in rat molars during orthodontic tooth movement (OTM).Materials and Methods:Twenty-one 12-week-old Wistar male rats were divided into three groups: OTM only (control [CG]), OTM and LED irradiation (DG), and OTM and low laser irradiation therapy (LG). The distance between the first and second molars was used to evaluate the amount of tooth movement. The mesial surfaces of the distopalatal roots were analyzed by scanning electron microscopy, and the area of the resorption was calculated.Results:Statistical analysis showed a decreased amount of tooth movement in the exposed DG or LG compared with CG, which was statistically significant (P = .031 and P = .004, respectively). However, when the DG and LG groups were compared, no statistically significant differences were found (P = .504). The root resorption areas were similar between CG and DG. However, statistically significant differences were found between LG and CG (P = .014) and LG and DG (P = .038).Conclusions:Phototherapy did not enhance tooth movement, while infrared laser irradiation did increase root resorption.     

低强度脉冲超声促进大鼠正畸性牙根吸收的修复

目的 研究低强度脉冲超声(low-intensity pulsed ultrasound,LIPUS)对大鼠正畸性牙根吸收的作用.方法 158只Wistar大鼠建立正畸牙移动根吸收的动物模型,100 g初始力值加载于大鼠右侧上颌两中切牙与第一磨牙之间14 d,随机分为空白对照组、加力组、100 MW/cm2超声治疗组和...     

辛伐他汀抑制正畸牙齿移动后复发距离的实验研究

目的探讨全身给予辛伐他汀对大鼠实验性牙移动后牙齿复发距离的影响。方法选用32只雄性Wistar大鼠，随机分成4组：对照组（生理盐水）、低剂量组（2．5mg／kg）、中剂量组（5．0mg／kg）、高剂量组（10．0mg／kg），牵引其上颌第一磨牙向近中移动。实验组在加力装置去除前1天开始，腹膜下注射辛伐他汀，对照组注射生理盐水，每日1次，连续4周。分别在加力装置去除时及其后1周、4周，测量上颌第一、第二磨牙间距离，测量体重。结果①各组大鼠体重无明显变化（P〉0．05）。②低、中、高剂量组大鼠牙齿移动复发距离小于对照组（P〈0．05）、复发百分率明显低于对照组（P〈0．01），且剂量越小复发程度越小，低剂量组复发百分率最低。结论辛伐他汀能有效地抑制实验性牙移动后牙齿复发的程度，低剂量时效果最明显。     

Effects of different types of tooth movement and force magnitudes on the amount of tooth movement and root resorption in rats

Objective:To investigate differences in the amount of tooth movement and root resorption that occurred after tipping and bodily movement of the maxillary first molar in rats.Materials and Methods:Ten-week-old female Wistar rats were divided into two groups according to type of tooth movement and subdivided into four subgroups according to the magnitude of applied force. Nickel-titanium closed-coil springs exerting forces of 10, 25, 50, or 100 g were applied to the maxillary left first molars to induce mesial tooth movement. We designed a novel orthodontic appliance for bodily tooth movement. Tooth movement distance and root resorption were measured using microcomputed tomography and scanning electron and scanning laser microscopy.Results:The amount of tooth movement in the bodily tooth movement group was less than half that in the tipping tooth movement group. The greatest amount of tooth movement occurred in the 10-g tipping and 50-g bodily tooth movement subgroups, and the amount of tooth movement decreased with the application of an excessive magnitude of force. Conversely, root resorption increased when the heavier orthodontic force was applied in both groups. Root resorption in the tipping tooth movement group was approximately twice that in the bodily tooth movement group.Conclusions:Root resorption in the tipping tooth movement group was more pronounced than that in the bodily tooth movement group. Although the amount of tooth movement decreased when extremely heavy forces were applied, root resorption increased in both the tipping and bodily tooth movement groups in rats.     

Efficacy of piezocision on accelerating orthodontic tooth movement: A systematic review

Objectives:The aim of this systematic review was to evaluate the effect of piezocision as an adjunctive procedure to accelerate orthodontic tooth movement.Materials and Methods:Randomized controlled trials and controlled clinical trials that investigated the effectiveness of piezocision on accelerating orthodontic tooth movement were identified through electronic and manual searches. The literature search, study inclusion, risk of bias assessment, and data extraction were performed by two reviewers independently.Results:Four eligible studies were included in this review. All studies reported accelerated tooth movement after piezocision, and three reported a significant reduction of treatment duration in the piezocision group. No deleterious effects on periodontal status, pain perception, satisfaction, root resorption, or anchorage control were reported in any studies.Conclusion:Based on currently available information, weak evidence supports that piezocision is a safe adjunct to accelerate orthodontic tooth movement, at least in the short term. More high-quality clinical trials to determine the long-term effects and optimal protocol for piezocision are needed to draw more reliable conclusions.     

正畸牙移动过程中破骨细胞出现区应力特点的三维有限元法分析

目的探讨大鼠磨牙近中倾斜移动时破骨细胞出现区的应力特点。方法大鼠上颌第一磨牙在40g、100g力作用2周后，制作连续牙周切片，进行组织学观察，同时建立其三维有限元模型，将组织切片与应力分布的结果对比观察，分析牙周膜内破骨细胞出现区的应力特点。结果无论100g还是40g力作用下，破骨细胞出现频数最高区域的最小主应力(Min)以及应力在牙齿移动方向上的分量(S11)均在一个较小应力范围内，而Max、Von Mises应力则无此现象。同一力作用下破骨细胞出现区的应力仅S11不随牙根不同部位的变化而变化。结论大鼠磨牙倾斜移动时破骨细胞出现与牙齿移动方向上的应力分量、最小主应力分布有着密切的联系。     

正畸牙移动过程中血小板源性生长因子-BB在牙周组织中的表达

目的观察正畸牙移动过程中血小板源性生长因子（platelet—derived growth factor,PDGF）．BB在牙周组织中的表达分布情况,探讨其与牙周组织改建的关系。方法36只Wistar大鼠随机分为加力1d、3d、7d、14d、21d组及对照组。建立正畸牙移动模型,采用苏木素-伊红染色和免疫组化法,对PDGF—BB半定量、定位分析。结果PDGF-BB主要定位于成纤维细胞、成骨细胞、破骨细胞、血管内皮细胞,施力后表达显著增强,压力侧加力第7天达峰值,张力侧加力第14天达峰值,此后表达下降。结论PDGF-BB作为局部调控因子参与了正畸牙周组织改建过程。     

Lithium chloride reduces orthodontically induced root resorption and affects tooth root movement in rats

Objective:To investigate the influence of lithium chloride (LiCl) on orthodontic tooth movement (OTM), orthodontically induced root resorption (OIRR), and bone morphometry.Materials and Methods:Ten-week-old female Sprague Dawley rats (n = 32) were divided into four groups based on the concentration of LiCl administered daily per kilogram body weight: 0 (control group), 0.32, 0.64, and 1.28 mM/kg body weight. The maxillary left first molars were moved mesially by a 10 cN coil spring for 14 days. Micro-computed tomography, scanning electron microscope, and scanning laser microscope images were taken to measure the amount of OTM, the volume of OIRR, and bone morphometry.Results:OIRR clearly decreased depending on the amount of LiCl administered, although OTM moderately decreased. The tooth inclined mesially and the root apex moved distally in the control and 0.32 mM groups. On the other hand, the tooth inclination angle became smaller and the root apex moved mesially in the 0.64 and 1.28 mM groups. In bone morphometry, the cortical bone mineral content and bone volume increased because of LiCl administration, and the trabecular bone measurements decreased. OIRR negatively correlated to the cortical bone measurements, and the amount of OTM significantly correlated to the cortical bone morphometry.Conclusions:In rats, LiCl reduced OIRR, which induced mesial movement of the tooth root apex. OIRR positively correlated to cortical bone morphometry.