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。     

拔牙区骨改建对邻牙移动速度的影响

目的　本研究通过对拔牙创的骨改建进程及矫治力对牙齿移动的影响进行研究,为临床医生选择理想的矫治力和牙齿移动时机,缩短矫治时间提供依据。方法　取SD大鼠36只,随机分为3组,全麻下拔除一侧上颌第一磨牙,3月后拔除另一侧上颌第一磨牙。在拔牙后不同的时间制作口内矫治器,分别以0·30、0·60、1·36 N的力牵上颌第二磨牙向拔牙区移动,分别在施力前及施力后的第1、3、5、7、10、14天拍摄X线片,利用图像处理技术, 测量牙齿移动距离,以置入的拔髓针校正放大率。结果　①牙齿向新鲜拔牙区移动的速度明显大于向已愈合拔牙区移动的速度。②无论向新鲜拔牙区移动还是向已经愈合的拔牙区移动,0·30 N力组牙齿移动的距离在各时间点与0·60 N、1·36 N力组牙齿移动的距离之间存在显著的统计学差异;而0·60 N与1·36 N力组牙齿移动的距离之间基本上从第5天开始差别不大。③加力后牙齿移动周期一般包括三个阶段:瞬时运动;迟滞期;后期移动阶段。大约在第14天时,由于矫治力衰减,牙齿停止移动。结论　①牙齿向新鲜拔牙区移动速度快,而向已经愈合的拔牙区移动速度慢。②在矫治过程中,中等力较为合适;即使使用较大的力,也不一定引起较大的牙齿移动。     

Effects of drugs and systemic factors on orthodontic treatment.

Orthodontic tooth movement and bone remodeling activity are dependent on systemic factors such as nutritional factors, metabolic bone diseases, age, and use of drugs. Therefore, a comprehensive review of the effects of these factors on orthodontic tooth movement is attempted in this article. Systemic hormones such as estrogen, androgen, and calcitonin are associated with an increase in bone mineral content, bone mass, and a decrease in the rate of bone resorption. Consequently, they could delay orthodontic tooth movement. On the contrary, thyroid hormones and corticosteroids might be involved in a more rapid orthodontic tooth movement during orthodontic therapy and have a less stable orthodontic result. Drugs such as bisphosphonates, vitamin D metabolites, and fluorides can probably cause a reduction of tooth movement after the orthodontic force is applied. Nonsteroidal anti-inflammatory drugs have also been shown to reduce bone resorption. Long-term administration of these drugs may therefore delay the necessary bone response to respective tooth-borne pressure and should not be administered for long periods of time to patients undergoing orthodontic tooth movement. Attention has also been focused on the effects of prostaglandins and leukotrienes in orthodontic tooth movement. It seems that they might have future clinical applications that could result in enhanced tooth movement. The use of the above drugs should be considered by every dentist in evaluating the treatment time and in planning treatment when tooth movement is attempted.     

增龄性因素对正畸牙齿移动过程中牙周组织细胞凋亡的影响

目的 探讨增龄性因素对大鼠正畸牙齿移动过程中牙周组织细胞凋亡的影响.方法 建立不同年龄组的正畸牙齿移动动物模型,在实验加力1d、3d、7d、14d及28d后,采用TUNEL方法检测牙齿移动过程中牙周组织细胞凋亡情况.结果 青少年组实验侧加力3d时,压力区细胞凋亡率显著增高,7d开始呈下降趋势,28d时细胞凋亡率基本同对照侧;成年组加力3d开始压力区细胞凋亡率逐渐增加,28d时细胞凋亡率开始降低.在牙齿移动过程中,成年组实验侧牙周组织细胞凋亡率明显高于青少年组.结论 细胞凋亡可能参与了正畸牙齿移动,但是增龄性因素使得成年组牙周组织细胞凋亡增加,进而影响各类细胞比例,改变牙周组织改建的速度和效果,使得牙齿移动速度减慢.     

大鼠正畸牙齿移动过程中牙周组织超微结构的改变

目的：研究正畸牙齿移动过程中牙周组织超微结构的改变情况。方法：施加外力使大鼠上颌第一磨牙向近中移动后，处死大鼠制备第一磨牙标本，进行透射电镜观察。结果：大鼠受正畸力作用后，组织各种生理、病理反应更加明显，压力侧破骨细胞增多，线粒体、溶酶体增多，高尔基体发达，成纤维细胞排列紊乱、变性、萎缩甚至坏死。张力侧成骨细胞、成纤维细胞的胞浆内高尔基体、内质网丰富，分泌功能旺盛。结论：正畸力引起牙周组织细胞功能的旺盛，改建活跃。     

Effect of orthodontic treatment on the periodontal tissues

Reduced periodontal support is a challenge that clinicians often face during rehabilitation of compromised dentition. The close and intricate relationship between the periodontal tissues and the processes of tooth movement suggest that adjunct orthodontic therapy may play an important role in overcoming these problems. On the other hand, excessive movement of teeth beyond the anatomic boundaries of the alveolar process is commonly believed to contribute to further destruction of the periodontal tissues. This review evaluates the clinical effects of various orthodontic tooth movements on the surrounding periodontal soft tissues and alveolar bone. Another objective was to identify possible patient and treatment‐related factors that may influence the response of periodontal tissue to specific orthodontic treatments. Particular emphasis is placed on specific tooth movements, such as extrusion, intrusion, space closure and arch expansion. Limitations of current research are also highlighted and discussed.     

帕米膦酸钠对大鼠正畸牙移动过程中破牙骨质细胞及破骨细胞分化因子表达的影响

目的:研究帕米膦酸钠对大鼠正畸牙移动过程中牙周组织压力侧破牙骨质细胞及破骨细胞分化因子(ODF)表达的影响.方法:选择24只6周龄SPF级健康雌性Wistar大鼠,建立正畸牙移动动物模型,每只大鼠上颌分实验侧和对照侧,于安装矫治器前3d,于实验侧大鼠第一磨牙近中腭侧黏骨膜下注射帕米膦酸钠50 μL,对照侧注射0.9％生理盐水50 μL,每3d注射1次.于正畸加力3、7、14 d时分批处死8只大鼠,制作牙周组织切片,观察破牙骨质细胞数量,免疫组化观察ODF的表达情况.采用PASW Statistics 18软件包对实验数据进行统计学处理.结果:实验侧在3、7、14d时,第一磨牙压力侧破牙骨质细胞的数目均少于对照侧,其中,7、14d时两侧差异显著(P＜0.05);实验侧在3、7、14d时,第一磨牙压力侧ODF阳性表达均低于对照侧,其中,7、14 d时两侧差异显著(P＜0.05).结论:局部注射二膦酸盐帕米膦酸钠能够减少大鼠正畸牙移动过程中牙周组织压力侧破牙骨质细胞的数量及ODF的阳性表达.     

Cone‐Beam Computed Tomography and Interdisciplinary Dentofacial Therapy: An American Academy of Periodontology Best Evidence Review Focusing on Risk Assessment of the Dentoalveolar Bone Changes Influenced by Tooth Movement

Background: The aim of this systematic review is to evaluate whether cone‐beam computed tomography (CBCT) imaging can be used to assess dentoalveolar anatomy critical to the periodontist when determining risk assessment for patients undergoing orthodontic therapy using fixed or removable appliances. Methods: Both observational and interventional trials reporting on the use of CBCT imaging assessing the impact of orthodontic/dentofacial orthopedic treatment on periodontal tissues (i.e., alveolar bone) were included. Changes in the alveolar bone thickness and height around natural teeth as well as treatment costs were evaluated. MEDLINE (via PubMed) and EMBASE databases were searched for articles published in the English language, up to and including July 2016, and extracted data were organized into evidence tables. Results: Thirteen studies were included in this systematic review describing the positive or deleterious changes on the alveolar bone surrounding natural teeth undergoing orthodontic tooth movement or influenced by orthopedic forces through fixed appliances. Clinical recommendation summaries presenting the strengths and weaknesses of the evidence in terms of benefits and harms were generated. Conclusions: CBCT imaging can improve the periodontal diagnostic acumen regarding alveolar bone alterations influenced by orthodontic tooth movement and can help determine risk assessment prior to such intervention. Clinicians are also better informed to determine risk assessment and develop preventative or plan interceptive periodontal augmentation (soft tissue and/or bone augmentation) therapies for patients undergoing orthodontic tooth movement. These considerations are recognized as being especially critical for treatment approaches in patients where buccal tooth movement (expansion) is planned in the anterior mandible or involving the maxillary premolars.     

血小板衍生生长因子-BB与胰岛素样生长因子-Ⅰ联合应用对大鼠正畸牙牙周膜细胞整合素β3表达的影响

目的 观察血小板衍生生长因子-BB(PDGF-BB)与胰岛素样生长因子-Ⅰ(IGF-Ⅰ)联合应用对大鼠正畸牙压力侧牙周膜细胞(PDLCs)中整合素β<,3>蛋白表达的影响.方法 建立SD大鼠正畸牙移动模型,隔日于正畸牙颊侧牙龈黏膜下单独或联合注射10ng PDGF-BB及200ng IGF-Ⅰ,加力10d后处死大鼠,取...     

Tooth movement and changes in periodontal tissue in response to orthodontic force in rats vary depending on the time of day the force is applied.

The purpose of this study was to investigate whether there are any differences in tooth movement or in the response of periodontal tissue to orthodontic force when the force is applied at different times of the day. One hundred 6-week-old male Wistar rats were divided into one control group without force application and three experimental groups based on the time of day the force was applied to the upper first molars. Animals in the whole-day group received force continuously throughout the experimental period, while animals in the light- and dark-period groups received force only during the light (07:00-19:00) or dark period (19:00-07:00), respectively. Tooth movement was measured using the occlusal view of a precise plaster model with a profile projector. Periodontal tissues were evaluated histologically. The time course of tooth movement varied among the groups. Tooth movement over 21 days in the whole-day and light-period groups was about twice that as in the dark-period group. The formation of new bone on the tension side in the whole-day and light-period groups was more than twice that as in the dark-period group. On the pressure side, more osteoclasts appeared on the alveolar bone in the whole-day and light-period groups than in the dark-period group. The light-period group showed less extensive hyalinization of the periodontal ligament (PDL) than the whole-day group. The area of root resorption on day 21 also varied among the groups. Interference by masticatory forces did not seem to be a principal cause of the decreased tooth movement in the dark-period group. These results indicate that there are considerable variations in tooth movement and in the response of periodontal tissue to orthodontic force when the force is applied at different times of the day in rats. The results suggest that diurnal rhythms in bone metabolism have important implications in orthodontic treatment.     

正畸牙移动过程中Cbfa1/Osf2在牙周组织中的表达

目的：了解Cbfa1/ Osf2在牙周组织中的表达及变化,探讨其在牙周组织改建中的作用,为进一步深入研究正畸牙移动的机制奠定基础.方法：建立大鼠正畸牙移动的动物模型,并采用免疫组织化学的方法检测Cbfa1/Osf2在此过程中的表达.结果：Cbfa1/ Osf2在加力组牙周组织中的表达明显强于对照组,且张力侧表达强于压力侧;其中成骨细胞、成纤维细胞及破骨细胞均为强表达.结论：Cbfa1/Osf2参与了牙移动过程中牙周组织的改建,可能在牙周膜细胞向成骨细胞转化及新骨形成中起到了重要的作用.     

Biomechanical aspects of external root resorption in orthodontic therapy

External apical root resorption is a common phenomenon associated with orthodontic treatment. The factors relevant to root resorption can be divided into biological and mechanical factors. Some mechanical and biological factors might be associated with an increased or decreased risk of root resorption during orthodontic treatment. For mechanical factors, the extensive tooth movement, root torque and intrusive forces, movement type, orthodontic force magnitude, duration and type of force are involved. For biological factors, a genetic susceptibility, systemic disease, gender and medication intake have been demonstrated influence root resorption. Orthodontic therapy of patients with increased risk of root resorption should be carefully planned. Medical history, medication intake, family history, tooth agenesis, root morphology, oral health and habits must be considerate if we do not want jeopardize our patients by severe root resorption. To monitor apical root resorption the standard procedure is a radiographic examination after 6 months of treatment. In teeth with enhanced risk, a 3-month radiographic follow-up is recommended. The administration of anti-inflammatory drugs might suppress root resorption induced by orthodontic therapy, although none study was enough conclusive to indicate a protocol for patients with enhanced risk. In the event of multiple external root resorption, the diagnostic procedure should focus on the exclusion of the local factors and its associations (such as magnitude, duration and type of orthodontic force; periodontal disease; root form) that might lead to external root resorption. Systemic disorders associated with phosphorus-calcium metabolic alterations shall be suspected. This review searched the current knowledge of the mechanical and biological aspects of root resorption in orthodontic tooth movement.     

Periodontal healing following orthodontic movement of rat molars with intact versus damaged periodontia towards a bony defect

The aim of this research was to determine whether orthodontic tooth movement influences periodontal healing. In 16 male Wistar rats, 12 week of age, a bony defect was created mesial to both maxillary first molars, not including the attachment apparatus (group 1), and in 15 animals, the defect included the periodontal ligament (group 2). In both groups, the right first molar was moved mesially (orthodontic side) for 2 weeks followed by a 1-week retention period; the contralateral molar was not moved (control side). Histomorphometric analysis was performed. The results within and between the different treatment groups and sides were statistically compared by t-test and analysis of variance with repeated measures on logarithmic transformation. Junctional epithelium was significantly larger at the control than at the orthodontic side of both groups (P = 0.024), and significantly larger in group 2 than in group 1 (P < 0.001). A significantly (P = 0.034) larger pocket depth was found at the control side in group 1. Supracrestal connective tissue was larger at the control than at the orthodontic side for both groups and significantly larger in group 2 than in group 1 (P = 0.004). Root resorption was found infrequently only at the orthodontic side in both groups (five out of 31 cases). The principal findings suggest favourable effects of orthodontic tooth movement on restraining epithelial apical down-growth and decreasing pocket depth. Orthodontic treatment could not completely avoid formation of a long epithelial attachment. Therefore, periodontal regenerative surgery might be indicated prior to orthodontic tooth movement. Orthodontic movement, shortly after periodontal surgery, had no detrimental effect on periodontal soft tissue healing or on diminished but non-inflamed periodontal tissues.     

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。     

大鼠正畸牙移动过程中牙周膜骨硬化蛋白的表达

目的 观察正畸牙移动过程中大鼠牙周组织中骨硬化蛋白（Sclerostin）的表达及分布,研究Sclerostin在正畸牙移动骨改建中的作用。方法 选取24只Wistar大鼠,安装加力装置,加载50 g力近中移动左侧第一磨牙,分别于安装加力装置后的0、1、3、5、7、14 d处死大鼠,用苏木精-伊红（HE）染色观察第一磨牙牙周组织形态学变化,抗酒石酸酸性磷酸酶（TRAP）染色观察破骨细胞的数量变化,免疫组织化学染色方法探究第一磨牙牙周膜中Sclerostin的表达变化。结果 HE染色显示随加力时间的延长压力侧骨组织破坏逐渐加重,免疫组织化学染色显示Sclerostin的表达逐渐增加,5 d时达到高峰,之后又逐渐降低,压力侧表达多于张力侧。结论 Sclerostin可能通过Wnt信号通路或者直接或间接控制骨形态发生蛋白参与了正畸牙移动骨改建过程。     

机械敏感离子通道Piezo1在糖尿病大鼠牙移动过程中的表达和功能研究

目的 研究糖尿病大鼠正畸牙齿移动中张力侧牙周组织内Piezo1的表达变化,探索其在张力侧牙周组织改建中的作用。方法 选取60只健康雄性Wistar大鼠为研究对象,分成对照组以及糖尿病组,以双侧切牙为支抗施加40 g拉伸力近中移动左侧第一磨牙,分别在0、7、14 d处死大鼠后获得左上后牙区牙槽骨块。HE染色检测组织形态变化,免疫组化及荧光染色检测张力侧Piezo1、Osterix以及Runx2的表达水平,Micro-CT检测张力侧骨组织相关参数指标。结果 正畸牙移动激活了张力侧牙周膜中Piezo1的表达,糖尿病大鼠Piezo1以及成骨分化关键转录因子Osterix和Runx2的表达显著低于健康大鼠。结论 糖尿病显著抑制了正畸牙移动过程中张力侧牙周膜中Piezo1的表达,降低了张力侧成骨活性,抑制正畸牙移动张力侧牙周组织的改建。     

伊班膦酸钠对正畸源性牙根吸收面积的影响

目的:通过牙齿移动距离的差异、牙周组织中破牙骨质细胞数量的变化及牙根吸收面积的差异,研究伊班膦酸钠对大鼠正畸源性牙根吸收的作用。方法:48只SPF级雌性Wistar大鼠,建立正畸牙齿移动动物模型,设置自身对照,对照侧为对侧未注药侧。在大鼠上颌双侧第一磨牙与上切牙之间安置一0.012英寸镍钛拉簧,施力60 g左右,所有大鼠均于安装矫治器前3 d在实验侧(大鼠上颌左侧)移动牙齿近中腭侧黏骨膜下局部注射50μL伊班膦酸钠,对照侧(大鼠上颌右侧)注射50μL 0.9%氯化钠液。每3 d注射一次直至实验结束。实验第3、7、14 d随机选择8只大鼠处死。分离大鼠头颅骨,用游标卡尺(精确度0.02 mm)测量上颌双侧第一磨牙移动的距离,并制备大鼠第一磨牙及其牙周组织切片,HE染色观察两侧牙周组织形态学变化,观察破牙骨质细胞的数量,采用图像处理软件对两侧的牙根吸收指数进行分析。结果:①牙齿移动距离随实验时间延长逐渐增加,组间比较:实验第3 d,实验侧和对照侧的牙齿移动距离平均值差异无统计学意义;实验第7 d和14 d,实验侧的牙齿移动距离均小于对照侧,差异具有统计学意义(P<0.05)。②实验侧第3 d、7 d和14 d大鼠第一磨牙牙周组织压力侧破牙骨质细胞数量均小于对照侧,且第7 d和14 d结果差异具有统计学意义(P<0.05)。③实验侧第3 d、7 d和14 d大鼠牙根吸收指数均小于对照侧,牙根吸收程度均比对照侧轻,且第7 d和14 d结果差异具有统计学意义(P<0.05)。结论:局部应用伊班膦酸钠可以减缓正畸牙齿移动的速度,减少牙周组织压力侧破牙骨质细胞的数量,减少正畸源性牙根吸收的发生。     

持续力和间歇力对牙移动骨改建的影响

正畸矫治力的作用时间对牙移动和牙槽骨改建的速度有直接影响,国内外许多学者对此进行了研究。该文就持续力和间歇力对牙移动速度、牙周膜牙槽骨改建和牙体应力反应的影响作一简要综述。选择合适的正畸加力方式,有助于临床医师有效控制牙移动,缩短正畸疗程。     

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.     

Experiments to Determine the Material Properties of the Periodontal Ligament

PHYSIOLOGY OF THE PERIODONTAL LIGAMENT: The periodontal ligament is a soft biological tissue that controls tooth movement under physiological loads by joining tooth and alveolar bone. Its various components differ in their material properties. Their spatial configuration and interaction are responsible for the reaction of the tissue in a loading situation. Due to the combination of fluid and elastic elements the periodontal ligament shows a viscoelastic behavior typical of soft biological tissues. It is characterized by non-linearity and time dependency, and additionally depends on loading history. BEHAVIOR UNDER EXTERNAL LOADS: In orthodontics, external loads are applied to the tooth crowns using orthodontic appliances. Since stresses and strains in the periodontal tissue, caused by the initial tooth movement, stimulate alveolar bone remodeling and thus orthodontic tooth movement, knowledge of the material properties of the periodontal ligament is fundamental to selection of an optimal force system for targeted tooth movement. OWN EXPERIMENTS: For this reason, typical properties of the viscoelastic material behavior of the periodontal ligament were tested experimentally in the present study, using samples from pig mandibles. This enabled the properties of force relaxation and hysteresis of this tissue, both of which depend on loading history, to be verified. CONCLUSION: The experimental results allow characterization of the tissue and thus contribute to an understanding of the biomechanics of tooth displacement under externally applied loads.