局部注射重组人转化生长因子对大鼠正畸牙移动的影响

目的:探讨局部注射重组人转化生长因子 (rhTGF -β1)对大鼠正畸牙移动速度的影响。方法:80只模型大鼠随机分为实验组和对照组,每组又按1、4、7、10和14 d再分为5个小组,每小组8只。实验组从加力的第1天开始,每2 d在大鼠加力侧上颌第一磨牙颊侧黏膜下注射rhTGF-β1 0.1 mL(5 ng/mL),对照组注射相同容量的PBS。加力后依实验设计时间分别处死每1小组大鼠。体视显微镜观察并采集图像,运用计算机图像分析软件测量牙移动的距离,同时应用TRAP组织化学染色观察不同时段压力侧破骨细胞数量的变化,采用SPSS 17.0 软件包对数据进行统计学分析。结果:局部注射rhTGF-β1的牙移动速度较对照组快,在加力后第7天,牙移动距离差异显著(P<0.05);第10天和第14天相比,差异显著(P<0.01)。实验组压力侧破骨细胞的TRAP阳性细胞数较对照组显著增多(P<0.01)。结论:局部注射rhTGF-β1增强了大鼠正畸牙破骨细胞的活性,促进了破骨细胞的骨吸收功能,加速了正畸牙移动。     

Compensatory bone formation in young and old rats during tooth movement

The aim of this study was to investigate compensatory lingual alveolar bone formation during tooth movement in young and old rats, using the vital bone marker tetracycline. Wistar male rats were separated into the following groups: 13-week-old rats without appliances (13C: control, n = 5), 60-week-old rats without appliances (60C: control, n = 5), 13-week-old rats with appliances (13E: experimental, n = 10), and 60-week-old rats with appliances (60E: experimental, n = 10). The upper first molars of the 13E and 60E groups were moved lingually using fixed appliances. On the third day of tooth movement, tetracycline (TC) was intra-peritoneally injected in all animals including the controls. On the 21st day of tooth movement, the animals were killed and unfixed, and undecalcified, 5-microm frozen frontal sections of the rat first molar areas in both control and experimental groups were examined under light and fluorescent microscopes. In the 13C group without tooth movement, tetracycline labelling lines were obvious in the alveolar crest, apical areas, and interradicular septum, indicating vertical alveolar bone growth. However, in the 60C control group, tetracycline labelling was almost undetectable throughout the alveolar bone. Although the lingual alveolar crest was resorbed from the periodontal side after lingual tooth movement, the sharp, bright labelling lines were still present from the crest to the lingual periosteal alveolar bone in the 13E group. In the 60E group the lines appeared in the lingual periosteal alveolar bone containing the crest, indicating considerable new bone formation. The results indicate that compensatory bone formation occurs in the alveolar crest area and, consequently, alveolar bone height is maintained, even in aged rats.     

Conference Report

Abstract

The influence of the anticonvulsive drug phenytoin on the periodontal tissues during orthodontic tooth movement in the rat was studied. The experimental and the control group each consisted of 10 Sprague-Dawley rats. The test group was injected daily with phenytoin during the experimental period of 6 weeks. A fixed appliance for expansion was applied on the first molars in both groups after 2 weeks (day 15). At the end of the experiment (day 42), radiographic measurements revealed less tooth movement in the phenytoin-treated rats. Compared to the control group, significant histologic changes in the periodontal tissues such as increased density of fibroblasts, decreased number of osteoclasts in contact with alveolar bone wall of the pressure side and deeper layer of non-mineralized osteoid on the tension side were observed in the phenytoin group.     

重组人类可溶性受体对大鼠正畸牙移动影响的研究

目的研究局部注射不同浓度重组人类可溶性受体对大鼠正畸牙移动进程的影响，了解其在牙周局部发挥作用的最小有效浓度范围。方法选取52只雄性SD大鼠，随机分为四组，用螺旋拉簧牵引大鼠左上第一磨牙近中移动，实验组第一天起局部分别注射不同浓度的重组人类可溶性IL-1和TNF受体，14天后测量磨牙移动距离，并制作切片进行HE及TRAP染色分析。结果与对照组相比，各受体组浓度为4ug／ml、0．8ug／ml、0．16ug／ml小组磨牙移动距离均大幅度减少（P〈0．01），牙槽骨表面及牙根表面TRAP染色阳性细胞数量也明显减少（P〈0．01），而浓度为0．032ug／ml小组却没有统计学意义（P〉0．05），且各受体组相同浓度小组问差异无统计学意义（P〉0．05）。结论在大鼠正畸牙局部注射重组人类可溶性受体发挥作用的最小有效浓度范围为0．032ug／ml-0．16ug／ml。     

Orthodontic tooth movement in the prednisolone-treated rat

Adverse effects of corticosteroids on bone metabolism raise concerns as to whether steroid treatment may influence orthodontic movement. This study examined the effect of prednisolone on orthodontic movement using an established rat model. The corticosteroid treated group (N = 6) was administered prednisolone (1 mg/kg) daily, for a 12-day induction period; the control group (N = 6) received equivalent volumes of saline. On day 12, an orthodontic appliance was placed which exerted 30 g of mesial force to the maxillary first molar. Animals were sacrificed on day 24 and tooth movement was measured. Sagittal sections of the molars were stained with haematoxylin and eosin, and for tartrate-resistant acid phosphatase (TRAP) activity. While there were no significant differences in the magnitude of tooth movement between the 2 groups, steroid-treated rats displayed significantly less root resorption on the compression side and fewer TRAP-positive cells within the PDL space on the same side. This suggests steroid treatment suppressed clastic activity.     

Evening primrose oil effects on osteoclasts during tooth movement

This study was conducted to investigate the influence of supplemented evening primrose oil (EPO) on osteoclast expression during experimental tooth movement in rats. Forty-eight 10-week-old male Sprague-Dawley rats were divided into experimental and control groups. Animals in the experiment group were fed a 7.25 g/kg daily dose of EPO orally by gastric intubation for 20 days before orthodontic tooth movement. The animals in the control group received an equivalent volume of distilled water by the same method. On day 21, a 40-g mesial tipping force was applied to the maxillary right first molar of each rat. After loading, six animals in each group were sacrificed on days 0, 3, 7, and 14 with the appliance in situ. On day 3, the number of osteoclasts on the appliance side of the experimental group was significantly increased compared with the control group (P < .05). On day 7, the number of osteoclasts on the non-appliance side of the experimental group was significantly increased compared with the control group (P < .05). This study indicates that oral administration of EPO can increase the number of osteoclasts and may accelerate orthodontic tooth movement.     

辛伐他汀对大鼠牙移动后牙周组织中骨形成蛋白2表达的影响

目的 明确全身给予辛伐他汀对大鼠牙齿移动后复发的影响,探讨辛伐他汀促进牙齿稳定的作用机制.方法 选用32只雄性Wistar大鼠,随机分成4组:对照组(0.9%NaCl)、低剂量组(2.5 mg·kg-1 辛伐他汀)、中剂量组(5.0 mg·kg-1 辛伐他汀)、高剂量组(10.0 mg·kg-1辛伐他汀),牵引其上颌第一磨牙向近中移动,持续21 d.实验组在加力装置去除前1 d开始,腹膜下注射辛伐他汀,阴性对照组注射生理盐水,每天1次,连续4周.分别在加力装置去除时及其后1、4周,测量上颌第一、第二磨牙间距离.取上颌第一磨牙及其牙周组织行组织学切片,HE染色及骨形成蛋白2(BMP-2)免疫组织化学染色,并进行图像分析和统计.结果 ①低、中、高剂量组大鼠牙齿移动复发距离均小于对照组(P＜0.05)、复发率明显低于对照组(P＜0.01),且剂量越小复发程度越小,低剂量组复发率最低(1、4周的复发率分别为26.81%、53.38%);②牙周组织中BMP-2表达量,低、中、高剂量组均高于对照组,差异有统计学意义(P＜0.001),低剂量组灰度积分增高最明显(P＜0.001);牙周组织中BMP-2表达,张力区略高于压力区,差异无统计学意义(P＞0.05).结论 在正畸牙齿移动后复发的过程中,辛伐他汀能有效抑制实验性牙移动后牙齿复发的程度,低剂量的辛伐他汀效果最明显.其作用可能是通过促进牙周组织中BMP-2蛋白的表达,加速成骨细胞活动,促进骨形成,促进移动后的牙齿稳定.     

Effects of calcitonin on orthodontic tooth movement and associated root resorption in rats

Objectives: Our main aim was to evaluate the effects of calcitonin (CT) on orthodontic tooth movement (OTM) and orthodontic root resorption in a rat model.

Material and methods: Eighty male Wistar rats were randomly divided into five groups. Rats in the negative control group were not given any appliances or injections. All the remaining rats were used to establish a model of OTM. The positive control group were then injected with normal saline, while rats in the three experimental groups were injected with 0.2?IU, 1?IU or 5?IU/kg/day CT. Nickel-titanium closed-coil springs were used to deliver an initial 50?g mesial force to the left maxillary first molar for 14 days in rats in the positive control group and the experimental groups. Each group was randomly subdivided into two groups, one for analysis of tooth movement, tissue changes and tartrate-resistant acid phosphatase (TRAP)-positive cells in alveolar bone, the other to examine root resorption by scanning electron microscopy.

Results: The OTM distance, the number of force-induced osteoclasts and root resorption areas were significantly decreased in CT-injected rats in a dose-dependent manner.

Conclusions: Administration of CT reduces the root resorption area and may therefore be effective as a novel adjunctive orthodontic approach to diminish undesired tooth movement via enhancing anchorage or preventing relapse after OTM.     

帕米膦酸钠对大鼠正畸源性根吸收及牙移动影响的研究

目的 研究帕米膦酸钠对大鼠正畸源性根吸收及牙移动的作用。 方法 选取48只6周龄SPF级Wistar雌性大鼠建立正畸牙移动模型,每只大鼠上颌分实验侧和对照侧,实验侧在大鼠左侧第一磨牙近中腭侧黏骨膜下注射0.5 mmol/L帕米膦酸钠50 μl,对照侧注射0.9%生理盐水50 μl,每3天注射1次。分别于实验第3、7、14天时分批处死16只大鼠,随机选择8只测量牙移动距离并制作牙周组织学切片进行牙根吸收指数的测定,另外8只用扫描电镜观察牙根吸收情况。实验数据用PASW statistics18软件进行处理。 结果 实验侧与对照侧牙移动的距离均随着时间的延续逐渐增加,第3、7、14天时实验侧第一磨牙移动距离均小于对照侧,第7、14天时两者差异有统计学意义（P＜0.05）;组织学切片观察牙根吸收指数及电镜扫描结果都显示在第3、7、14天时实验侧相比对照侧牙根吸收少,在第7、14天时两侧牙根吸收程度的差异有统计学意义（P＜0.05）。 结论 局部注射二膦酸盐帕米膦酸钠能够抑制正畸牙移动过程中的牙根吸收,减缓牙移动的速度。     

大鼠牙移动中牙周膜功能状态与牙槽骨改建关系的研究

目的:通过检测不同牙周膜功能状态大鼠磨牙移动过程中压力侧牙槽骨表面破骨细胞计数及牙移动距离的差异,探讨牙周膜功能状态与牙槽骨改建的关系.方法:选择48只6周龄体重(250±20)gSD大鼠,随机分为正常对照组(16只)和实验组(32只).通过拔除实验组大鼠右下颌所有磨牙使其上颌左、右第一磨牙咬合力改变,3周后分别形成牙周膜代偿性机能亢进模型和牙周膜废用性萎缩模型,据此实验组又分为萎缩组与亢进组(各16只).在各组大鼠上颌切牙和第一磨牙间放置5mm镍钛拉簧,初始力值60g,近中移动磨牙.分别于加力0d、3d、7d,每组各处死动物2只,14d处死其余动物,制备组织学标本,通过TRAP染色鉴别第一磨牙近中根压力侧牙槽骨表面破骨细胞并记数;对加力14d后的标本拍摄X线片测定牙齿移动距离.结果:牙周膜机能代偿性增强组牙齿移动距离(0.265±0.107mm)明显小于其它两组(0.631±0.142mm,0.679±0.090mm),P<0.01.牙周膜废用性萎缩组与正常对照组移动距离无显著性差异(P>0.05).萎缩组大鼠近中根压力侧牙槽骨表面破骨细胞计数在实验全过程中(除0d外)均低于亢进组和对照组,有显著性差异(P<0.05).结论:处于退化状态的废用性萎缩牙周膜对矫治力抵抗性差,细胞分化增殖不活跃,骨组织改建率低;机能代偿性增强牙周膜对矫治力抵抗性好,细胞分化增殖活跃,成骨活动大于破骨活动.     

外源性TGF-β1与PDGF-BB联合应用对正畸牙压力侧Pyk2蛋白和基因表达的影响

目的 探讨外源性生长因子-β1与外源性血小板衍生生长因子BB联合应用对牙周组织破骨细胞内Pyk2表达的影响。方法 160只SD大鼠随机分为2组,建立正畸牙移动模型。A组注射含rhTGF-β1与rhPDGF-BB的混合液 0.1 mL,B组注射相同容量的PBS。加力后1、4、7、10、14 d,分别处死每大组的1小组大鼠。测量牙移动距离变化,TRAP染色行破骨细胞计数,Pyk2蛋白和基因水平分别用免疫组织化学染色法和RT-PCR检测。采用SPSS19.0软件包对数据进行统计学分析。结果 2组牙移动距离在第4、7、10、14天均具有统计学差异（P<0.05）。A组压力侧破骨细胞计数显著高于B组,除第14天外,其余各时间点均具有显著差异（P<0.05）。A组Pyk2蛋白和基因表达均比B组高,2组均在第7天达到最高峰,除第1天外,其余时间点Pyk2蛋白表达均具有统计学差异（P<0.05）。第4、7天,2组Pyk2基因表达均具有统计学差异（P<0.05）。结论 外源性TGF-β1与PDGF-BB联合应用可从蛋白和分子水平上调正畸牙牙周组织压力侧Pyk2的表达,这可能是加速正畸牙移动速率的原因之一。     

Soluble cytokine receptor treatment in experimental orthodontic tooth movement in the rat

Pro-inflammatory cytokines, such as interleukin-1 (IL-1) and tumour necrosis factor-alpha (TNF-alpha), are believed to play a role in the biological processes involved in the course of orthodontic tooth movement and especially in root resorption. The inhibition of cytokine activity, e.g. by soluble receptors, could be beneficial in reducing this unwanted side-effect.The aim of this study was to investigate the role of cytokines IL-1 and TNF-alpha in the course of experimentally induced tooth movement. The upper left first molar was moved orthodontically in 80 male Wistar rats using a coil spring with a force of 0.5 N. Starting at day -1, three groups of 20 animals each received daily intraperitoneal injections (ip) of 2 ml of 1 mug/ml soluble receptors (a) to IL-1(sIL-RII), (b) to TNF-alpha (sTNF-alpha-RI) and (c) a combination of (a) and (b). Twenty animals served as the control. After 3, 6, 9 and 12 days, the animals were killed in groups of five. The amount of tooth movement was registered and the maxillae were prepared for histological and histomorphometric analysis. Osteoclasts and odontoclasts were identified using tartrate-resistant acid phosphatase (TRAP) histochemistry.The amount of tooth movement was reduced in all receptor-treated groups by approximately 50 per cent. At the same time, the number of TRAP-positive cells on the desmodontal bone surface and on the surface of the roots was reduced. Thus, systemic application of soluble receptors to IL-1 and TNF-alpha following experimental induction of tooth movement in the rat reduced the number of osteoclasts as well as odontoclasts.     

局部注射阿仑膦酸钠对大鼠正畸牙移动的影响

目的观察局部注射阿仑膦酸钠对大鼠正畸牙移动及牙周组织的影响。方法32只Wistar大鼠分为对照组和低剂量、中剂量、高剂量三个实验组,使用40g力牵其左侧上颌第一磨牙近中移动,实验中分别将生理盐水、0.02mmol/L、0.1mmol/L、0.5mmol/L的阿仑膦酸钠溶液注射入各组大鼠上颌第一磨牙近中腭侧的粘骨膜下,注射于实验前3d开始,每3天一次,每次50μl。分别在0、1、3、7、14、17、21d时取模法测量大鼠牙移动量。第21天取上颌组织块经固定、脱钙、脱水、包埋后切片,HE染色观察牙周组织变化,TRAP染色观察压力区破骨细胞数、破牙骨质细胞数,比较各组间是否有差异。结果①各实验组大鼠第一磨牙移动距离显著低于对照组,并随药物浓度增高其抑制效果增强。②实验组压力区破骨细胞数和破牙骨质细胞数显著低于对照组。结论局部注射不同浓度阿仑膦酸钠能获得不同的抑制牙齿移动的效果,可应用于临床中作为一种增强支抗的手段。     

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.     

正畸牙齿移动过程中内皮素的表达

目的:观察内皮素在大鼠正畸牙齿移动过程中牙周组织改建过程中的表达,探讨内皮素在正畸牙齿移动中的作用机制。方法:64只雄性SD大鼠随机分为8组。正畸加力1、3、5、7、14、21、28d组和对照组,牙周组织分别进行免疫组化染色、图像分析。结果:牙齿移动1d后内皮素表达开始增强,5d达到高峰(P<0.01),以后表达降低。结论:内皮素参与了正畸牙周组织改建过程。     

局部应用二磷酸盐对鼠正畸牙移动影响的研究

目的 探讨局部注射Zoledronate溶液对鼠正畸牙齿移动距离与牙周组织形态的影响。方法 选用42只雄性Wistar大鼠，牵引其上颌第一磨牙近中移动。实验中分别将Zoledronate溶液及生理盐水注射入实验组（左侧）及对照组大鼠（双侧）上颌第一磨牙腭侧的粘骨膜下。注射于实验前3d开始，共进行9次，每3d一次。分别在加力0、3、7、14、21d后记录上颌第一磨牙移动距离，组织HE染色后，观察牙周组织形态学的改变。结果 ①实验组大鼠牙齿移动距离明显低于对照组。②实验组大鼠压力侧破骨细胞数在实验全过程中均低于对照组，而根分叉区破牙骨质细胞数除加力14d外，2组差异无显著性。③实验过程中Zoledronate溶液对破骨细胞和破牙骨质细胞以外的细胞作用不明显。结论 Zoledronate能有效地抑制支抗牙移动，减少压力侧牙槽骨表面破骨细胞数。     

可溶性受体对大鼠正畸牙移动中牙周组织RANKL表达影响的研究

目的研究局部注射重组人类可溶性受体,在大鼠正畸牙移动进程中,对核因子κB配体受体激活子（Receptor activator of nuclear factor—κ Bligand,RANKL）的影响。方法选取52只雄性SD大鼠,随机分为四组,用镰钛螺旋拉簧牵引大鼠左侧上颌第一磨牙近中移动,加力第一天起局部注射给药,14天后处死,测量磨牙移动距离,制作左侧上颌骨标本切片,应用SABC免疫组织化学染色法对牙周组织中的RANKL进行半定量分析。结果各组大鼠正畸牙张力侧与压力侧牙周组织内均可见RANKL的表达;其中在压力侧,对照组与0．032μg／ml小组中见RANKL强阳性表达,而4μg／ml、0．8μg／ml及0．16μg／ml各小组RANKL的阳性表述面积百分比均明显降低（P〈0．01）,且随浓度的降低,各小组呈上升趋势且差异有高度统计学意义（P〈0．01）。结论有效浓度的重组人类可溶性受体抑制影响牙周组织RANKL的袁迭．减弱破骨细胞／破牙骨质细胞的作用。     

不同浓度木通皂苷D对大鼠正畸牙移动的影响

目的:探讨局部注射不同浓度的木通皂苷D对大鼠正畸牙移动的影响。方法:40只6周龄雌性Wistar大鼠,随机分为4组,建立正畸牙移动动物模型。以上颌两中切牙为支抗,牵引上颌第一磨牙向近中移动,镍钛拉簧加力40 g。ASD1组以5 mg/kg的剂量局部注射ASD溶液;ASD2组以10 mg/kg的剂量局部注射ASD溶液;PGE2组以25 μg/kg的剂量局部注射PGE2溶液;空白对照组注射生理盐水。4组动物分别于正畸加力3、7、14、21、28 d后分批处死,测量各期上颌第一磨牙的移动距离,H-E染色观察切片牙周组织及破骨细胞数量的变化,采用SPSS13.0软件包对数据进行统计学分析。结果:各实验组动物牙移动距离均大于对照组,加力第3天,只有PGE2组与对照组相比有显著差异（P<0.05）。加力第7天,ASD2组和PGE2组与对照组相比均有显著差异（P<0.05）。加力第14、21、28天,ASD1组、ASD2组和PGE2组与对照组相比均具有统计学意义（P<0.05）。各时间段ASD2组和PGE2组之间牙移动距离相比无统计学意义（P>0.05）。组织学观察,压力侧多核破骨细胞数目随时间推移呈上升趋势,第21天达到高峰,随后逐渐减少。结论:局部注射ASD可促进大鼠正畸牙移动,ASD以10 mg/kg的剂量局部注射,其作用与PGE2促进正畸牙移动的效果相似,较5 mg/kg剂量的ASD促进牙移动的效果明显。     

The effect of corticosteroid-induced osteoporosis on orthodontic tooth movement.

The purpose of this research was to study the effect of corticosteroid-induced osteoporosis on orthodontic tooth movement and relapse. Sixteen 3-month-old New Zealand white rabbits were divided into four equal groups, two treatment and two control. All treatment rabbits were administered daily injections of 15 mg/kg cortisone acetate for 4 days before and during the experimental period. An orthodontic appliance delivering a mesial force of 4 ounces was placed on the maxillary left first molar of all animals. For all groups, measurements of active tooth movement were made after 4, 7, 11, and 14 days. For two of the groups, appliances were removed on day 14, and additional measurements of relapse were made through day 21. With the use of radiodensitometric readings of the humerus bone and histology of the maxilla, osteoporosis was demonstrated in the treatment animals. Mean incremental and cumulative active tooth movement was three to four times greater (p < 0.0001) in the treatment rabbits than in the controls. The treatment group in which relapse was measured demonstrated 100% relapse on day 18, whereas the control group relapsed at a much lesser rate through day 21 and never achieved 100% relapse. Histologic findings appeared to support tooth movement results. In conclusion, the results of this study indicate that rabbits subjected to corticosteroid-induced osteoporosis undergo significantly more rapid orthodontic tooth movement and subsequent relapse than control animals.     

Effect of age on the rate of tooth movement in combination with local use of 1,25(OH)2D3 and mechanical force in the rat.

The purpose of this study was to compare the amount and rate of tooth movement in young and mature rats administered 1,25(OH)2D3 simultaneous with application of mechanical force. In 30 seven-week-old and 30 28-week-old male Wistar rats, the right maxillary first molar was moved buccally with a fixed appliance. The appliances delivered forces ranging from 5 to 20 g. Twenty microL of 1,25(OH)2D3 (10(-10) and 10(-8) mol/L) was injected locally into the submucosal palatal area of the root bifurcation of the right first molar. The left side was injected with phosphate-buffered saline (PBS). In young rats receiving 10(-10) mol/L 1,25(OH)2D3 every three days, tooth movement significantly increased to 126% of that in PBS-injected control rats on day 20. In 1,25(OH)2D3-injected mature rats, tooth movement was stimulated markedly and increased with 10(-10) mol/L to 245% and with 10(-8) mol/L to 154% of the amount of tooth movement seen in the PBS-injected controls by the end of the experiment. PBS-injected rats had a plateau stage where tooth movement did not occur at all, while there was no such lag-time in the 1,25(OH)2D3-injected group which showed continuous tooth movement. The local injection of 1,25(OH)2D3 did not change serum calcium, phosphate, and alkaline phosphatase activity, and there were no apparent clinical or microscopic side-effects.