富血小板血浆影响正畸牙齿移动效率的研究进展

富血小板血浆(PRP)是一种从自体血液中提取的血小板浓缩物,含有丰富的细胞因子和生长因子,其中血小板衍生生长因子、转化生长因子β、血管内皮生长因子主要对成骨细胞和破骨细胞的活性产生影响,促进骨重建过程。正畸牙的移动效率受到骨重建的影响,故局部注射PRP将是加速正畸牙齿移动效率的新方向。该文主要对PRP在正畸治疗中加速正畸牙移动效率的相关实验及其基础研究进行了综述,有助于进一步探讨PRP应用于临床治疗中加速正畸牙移动效率的可行性。     

消炎痛对正畸牙齿移动中牙周组织超微结构的影响

目的：在细胞水平上进一步研究消炎痛影响正畸牙周组织改建与牙齿移动的机理。方法：通过扫描和透射电子显微镜（ＳＥＭ和ＴＥＭ），观察牙周组织细胞超微结构的改变。结果：ＳＥＭ和ＴＥＭ观察表明，２５ｇ力可引起兔切牙牙周组织细胞超微结构发生改变，在压力和张力侧均出现损伤和修复性反应，消炎痛对正畸牙周组织细胞超微结构变化的影响包括两方面，一方面抑制了牙周组织的炎症反应和损伤，另一方面也抑制了组织的修复过程，从而抑制了正畸牙周组织改建和牙齿移动。结论：消炎痛可以抑制牙周组织对正畸力的反应，使牙齿移动速度减慢，在临床治疗中，对长期服用消炎痛类药物的患者，可能因此影响矫治效果，应引起足够重视。     

超声波对正畸牙移动过程中牙龈血流量影响的临床研究

目的：研究超声波对正畸牙移动过程中牙龈血流量的影响,探讨超声波加快正畸牙移动的效果及作用机制。方法：20例初诊正畸患者随机分为治疗组和对照组,每组各10例,两组病例在进行颌内牵引前先进行牙列整平,治疗组对颌内牵引的测试牙加力前3d进行超声波处理,对照组只进行颌内牵引,不进行超声波处理。两组病例均于术前1d,加力后1d、8d、16d测试血流动力学指数和累计牙移动量。结果：牙移动过程中牙龈血流动力学存在变化,超声波能显著增加动脉收缩期血流速度（Vs）、舒张期血流速度（Vd）,对动脉阻力指数影响不大。结论：超声波能显著提高牙周血流灌注量及加快牙周组织新陈代谢。     

牙槽骨微穿孔术加速正畸牙齿移动的研究进展

牙槽骨微穿孔术(micro-osteoperforations,MOPs)是一种创伤小、操作安全、费用低,正畸医生可以独自在椅旁完成的辅助正畸牙齿移动的干预措施。其理论基于区域加速现象(regional accelerated phenomenon,RAP),手术破坏骨组织导致术区周围骨密度降低,创伤刺激细胞调节机制使骨重建加速,达到加快正畸牙齿移动的目的。目前大部分研究验证其能够有效加速牙齿移动且可重复操作,但效果仍然存在争议,与其他加速正畸牙齿移动干预措施相比有其优缺点,本文就牙槽骨微穿孔术的提出、生物学反应、应用现状、目前可能出现的副作用作一综述,为该技术的最新发展及临床应用提供科学参考。     

The effect of cortical activation on orthodontic tooth movement

OBJECTIVE: Cortical activation is one of the procedures to accelerate tooth movement by manipulating the cortical bone. In this study, the effect of cortical activation on orthodontic tooth movement was investigated clinically and histologically in the surrounding bony tissue. MATERIALS AND METHODS: In the lower and upper jaws of two beagle dogs, cortical activation was applied to the buccal and lingual side of the alveolar bone in the right jaw where 12 holes were made on each cortical plate 4 weeks after the extraction of all the second bicuspids while under deep anesthesia. All third bicuspids on both jaws were forced to move forward by a 150-g force using NiTi coil spring with/without guiding wire. The tooth movement was measured and the animals were killed after tooth movement. RESULTS: Rapid initial tooth movement was apparent after cortical activation. However, after 6 months of cortical activation, the cell number and cellular activity of the surrounding periodontal tissue were decreased. CONCLUSIONS: This experiment showed that rapid initial tooth movement was apparent following the application of orthodontic force after cortical activation but the cellular activity and fibroblast structure were abnormal in the surrounding periodontal tissue.     

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目的建立实验性正畸牙移动保持期的动物模型,以利于研究保持期骨改建规律。方法于2008年4月在吉林大学口腔医院动物实验室,选用36只8周龄雄性Wister大鼠,以上颌前牙为支抗牵引第一磨牙向近中移动,加力21d后去除加力装置。以每只大鼠的左侧牙弓为实验侧,右侧牙弓为对照侧。在实验侧安装保持装置,分别保持1、3、7、14、21、28d;对照侧不做任何处理。在加力结束后和保持结束后即刻制取上颌石膏模型,测量所有模型的第一磨牙面近中沟与第二磨牙面远中沟的距离,计算加力结束后与保持结束后的距离,比较实验侧与对照侧的牙齿移动距离,评价保持装置的有效性。结果实验侧在保持结束后第一磨牙复发距离明显小于对照侧,二者差异有统计学意义(P<0.05)。结论以Wister大鼠为实验对象,采用正畸结扎丝结扎法建立的正畸牙移动保持期动物模型是有效的。     

骨皮质切开术对大鼠牙移动影响的实验研究

目的建立骨皮质切开术正畸牙移动实验动物模型,观察移动速率和对牙周组织改建的影响。方法 75只SD大鼠,实验组35只行上颌双侧中切牙骨皮质切开术,1周后与对照组35只同时进行正畸加力,空白对照组5只不进行加力。按不同加力时间处死,测量牙齿移动的距离,观察组织学改变。结果实验组2周时牙齿移动距离(3.471±0.359)mm,对照组为(1.247±0.198)mm,具有显著性差异;HE染色结果表明,实验组牙周膜内玻璃样变组织的形成相对于对照组来说,范围缩小,时间缩短。结论骨皮质切开术能够加速正畸牙移动。     

Inhibition of tooth movement by osteoprotegerin vs. pamidronate under conditions of constant orthodontic force

The undesired movement of anchor teeth, and relapse of previously moved teeth, are major clinical problems in orthodontics. Dental implants are increasingly used to preserve anchorage, but these are costly and require invasive surgical procedures. An alternative strategy for maintaining anchorage may be the use of biological inhibitors of osteoclastic bone resorption. In the present study, we investigated the relative efficacy of pamidronate vs. osteoprotegerin (OPG) in inhibiting bone resorption and tooth movement, using a new orthodontic model in mice in which maxillary molars are moved for prolonged periods by near-constant, clinically relevant forces. Osteoclast influx to compression sites was initiated on day 3, was maximal on day 4, and persisted until at least day 12 after force application. Tooth movement paralleled osteoclast numbers. Minimal osteoclast apoptosis was observed, suggesting that recruitment, rather than programmed cell death, is a critical regulatory mechanism under conditions of constant force. Osteoclasts were reduced at compression sites by both OPG (95%) and pamidronate (70%); tooth movement was more dramatically inhibited by OPG (77% vs. 34%). Our findings indicate that constant orthodontic force regulates the recruitment, activation, and viability of osteoclasts, and that OPG could have clinical utility in preventing undesired tooth movement.     

Adiponectin prevents orthodontic tooth movement in rats

ObjectiveThe objective was to examine the effects of repetitive local administration of adiponectin on experimental tooth movement in rats.Materials and methodsThe maxillary right first molar of male Wistar rats (n = 24) was moved mesially for 14 days, with local adiponectin injections (0.2 or 2 μg) every third day. Micro-computed tomography was performed at days 0, 6 and 14 and molar movement, bone density and bone volume fraction were calculated from the scans. Changes in extracellular matrix collagen and cell numbers in the periodontal ligament were analyzed histologically, and levels of circulating cytokines were measured by Luminex and ELISA.ResultsAdiponectin injections induced a reduction in tooth movement after 12 and 14 days compared to controls. No tooth movement was observed between days 3 and 14 in the group receiving the highest dosage (2 μg) of adiponectin. Differences in bone density and bone volume fractions between treatment and control groups were not identified. Relative size and morphology of collagen fibrils, and cell number in the periodontal region after adiponectin injections were unchanged compared to controls. Levels of circulating adiponectin or other selected factors in plasma were not influenced by the adiponectin injections.ConclusionsSubmucosal injections of adiponectin prevented experimental tooth movement in rats. The effect was dosage-dependent and local. Adiponectin injections caused no detectable changes in bone density, periodontal cell number or collagen content.     

正畸牙移动核心科学问题：目标位、效率、精准度

当今正畸牙移动技术体系已基本成熟,但总体疗效与治疗预期之间仍存在差距。经文献回顾及分析,笔者总结认为,正畸牙移动包含了三大核心科学问题：目标位、效率、精准度。围绕这三大问题的研究是进一步提升正畸疗效、推动正畸学进步的着力点。     

Relaxin is up-regulated in the rat ovary by orthodontic tooth movement

Relaxin (Rln) is an ovarian hormone that stimulates osteoclastic and osteoblastic activities and connective tissue turnover. To investigate the expression of Rln during orthodontic tooth movement, rats were implanted with orthodontic appliances that connected a spring from the upper incisors to the first molar with a 70 cN force. Rats in each group were killed 6, 48, and 144 h after activating the appliance, and the levels of Rln1 and Rln3 expression in the ovary were determined by real-time RT-PCR, northern blots, western blots, and immunofluorescence analyses. The amount of tooth movement induced by the orthodontic force increased in a time-dependent manner. The levels of Rln1 mRNA increased by 12-, 41-, and 263-fold at 6, 48, and 144 h, respectively, after orthodontic tooth movement. The time-dependent increase in the concentration of Rln 1 protein in the ovary was also confirmed by western blotting. Rln 1 was localized in the granulosa cells of the ovarian follicles, and the immunoreactivity against Rln 1 was increased by the movement. In contrast, the concentration of Rln 3 was below the level of detection. The results of this study suggest that local changes in periodontal tissues induced by orthodontic tooth movement may affect Rln1 expression in the ovary. However, further studies are needed to decipher the mechanisms involved and the possible contribution of the increased level of expression of Rln 1 to the tooth movement.     

偏侧咀嚼对正畸牙移动影响的实验研究

目的通过建立偏侧咀嚼大鼠模型,探讨偏侧咀嚼对正畸牙移动过程的影响。方法选择30只6～8周龄,（250±10）g,雄性SD大鼠,随机分为实验组与对照组,每组各15只。通过拔除实验组大鼠右下颌所有磨牙使右上颌第一磨牙丧失咬合接触建立大鼠偏侧咀嚼动物模型,同时,在两组大鼠双侧上颌切牙和第一磨牙间放置镍钛拉簧,初始力值为50g,近中移动磨牙。分别于第0、3、7、10、14天测量大鼠上颌第一磨牙近中移动的距离并通过HE染色观察大鼠上颌第一磨牙牙周组织形态学变化。结果各时间点代偿性咀嚼增强侧牙移动速率均小于对照组（P〈0.05）,牙周组织变化与对照组相似;失咬合侧牙移动速率大于对照组（P〈0.05）,牙周组织出现退行性改变;但三种咬合状态下牙齿移动速率曲线均表现为瞬时运动、迟滞期及后期移动三个阶段。结论动物实验证实偏侧咀嚼引起正畸牙牙周组织发生相应改变最终影响牙移动速率,但无论牙移动速率快慢,牙移动均符合正畸性牙移动的一般规律。