Micro-CT观测半导体激光照射对牙移动的影响

发布时间：2018-05-05 06:08

本文选题：Micro-CT + 半导体激光　；参考：《河北医科大学》2017年硕士论文

【摘要】：目的:随着我国居民生活条件的改善,近年来进行口腔正畸治疗的患者越来越多,但疗程一般两年多,有的甚至更长。在此期间,患者不注意口腔卫生,会引起牙龈炎、牙周炎、龋齿等疾病。在口腔正畸临床医治过程当中,牙齿移动的速度多数为每个月1毫米,为了加速牙齿移动,正畸学者们进行了大量研究,探讨加速牙齿移动的方法。目前加速牙齿移动的方法分为四类:手术治疗方法、基因治疗方法、药物治疗方法和物理治疗方法。手术方法具有一定的创伤性,基因治疗方法目前不太成熟,药物治疗方法可能会引起一些副作用。而激光照射属于物理治疗方法的一种,它主要通过加快破骨细胞和成骨细胞的形成达到加速牙齿移动的目的。其中半导体激光涵盖了其他类激光的应用范围,具有体积小、寿命长、成本低和使用安全等多种优点,作为一种没有创伤、操作简单方便的加速牙移动方法,更容易被患者和医生接受。在半导体激光照射下,牙槽骨骨结构发生了怎样的变化尚不清楚。有关牙齿移动的动物实验对象多为大鼠,通常用游标卡尺测量大鼠牙齿移动距离,结果不够精确,误差较大。在观察牙槽骨改建和牙根吸收时,常用组织学切片的方法,切片只能从二维角度进行观测。Micro-CT是空间分辨率高达1-10μm的医学CT,它可以从三维角度更加全面和精确的观察正畸牙齿移动距离、牙槽骨骨结构的变化和牙根吸收情况。本实验采用Micro-CT观测在半导体激光照射下正畸牙齿移动速度、牙槽骨微观结构变化和牙根吸收的情况,探讨半导体激光对牙移动的影响,从而为半导体激光在正畸临床上加速牙齿移动提供理论参考。方法:1建立大鼠牙移动模型10%水合氯醛腹腔麻醉(300-350mg/kg),上颌切牙与第一磨牙间使用镍钛螺旋拉簧加力。通过上颌两切牙作为支抗,牵引双侧上颌第一磨牙向近中移动,每侧力值为10g,见Fig.1。2半导体激光照射异氟烷吸入麻醉,见Fig.2。牙齿加力后1-14天,每天使用半导体激光照射(波长980nm,能量密度10J/cm2)右侧上颌第一磨牙区域,见Fig.3和Fig.4。3 Micro-CT扫描大鼠心脏灌注处死后,制取标本。用Micro-CT(Sky Scan1076,比利时)对标本进行扫描,扫描参数为每次旋转0.7°,总共旋转180°,73k V,142μA,层厚为18μm,图像大小为1024×1024像素。每个标本扫描时间大约为30分钟。然后运用Micro-CT自带的程序进行图片的重构,每个样本重构时间约40分钟,得到图片1000张左右,见Fig.5。使用CTAn软件,进行牙齿移动距离、牙根长度和牙槽骨骨结构各项参数的测量,见Fig.6和Fig.7。4制作组织学切片将标本放置于EDTA溶液中脱钙,石蜡包埋,制作以上颌第一磨牙为中心的、近远中方向的组织切片,常规HE染色。光镜下观察组织学变化。5统计分析采用SPSS 21.0统计软件进行数据分析。计量资料用均数±标准差(Mean±SD)表示,对正态分布且方差齐的数据采用单因素方差分析(one-factor ANOVA),两组间均数比较采用独立样本t检验,四组间均数比较采用方差分析,两两比较采用LSD检验。若非正态或方差不齐采用非参数的秩和检验Kruskal-Wallis H检验。取α=0.05作为检验水准,P0.05为差异有统计学意义。结果:1牙齿移动距离第3天,激光组牙齿移动距离与对照组相比无统计学差异(P0.05);第7天、14天两组均有显著差异(P0.05),激光组(7d:203.27±32.28μm,14d:320.80±33.82μm)明显大于对照组(7d:166.93±15.46μm,14d:259.40±30.01μm)。两组的牙齿移动距离在第0、3、7、14天时两两比较均存在显著性差异(P0.05)。第3-7天期间,两组牙齿移动速率均比第0-3天时慢;第7-14天期间,两组牙齿移动速率均比3-7天时快,见Fig.8和Table1、9、10。2牙根吸收情况第3天、7天,激光组牙根长度与对照组相比无统计学差异(P0.05);第14天,激光组牙根长度(1.93±0.10mm)显著大于对照组牙根长度(1.84±0.12mm)(P0.05)。激光组牙根长度在第0、3、7、14天时两两比较均无统计学差异(P0.05)。第14天,对照组牙根长度小于第0天、3天时的牙根长度(P0.05),见Fig.9和Table 2、9、10。3牙槽骨骨结构参数3.1压力侧牙槽骨骨密度(Bone Mineral Density,BMD)第3天,两组BMD值无统计学差异(P0.05);第7天、14天,激光组BMD值显著低于对照组(P0.05)。从0天-14天两组BMD值呈降低趋势,见Fig.10和Table 3、9、10。3.2压力侧骨体积分数(Bone Volume Fraction,BV/TV)第3天,两组BV/TV值无统计学差异(P0.05);第7天、14天,激光组BV/TV值显著低于对照组(P0.05)。从0天-14天两组BV/TV值呈下降趋势,见Fig.11和Table 4、9、10。3.3压力侧骨小梁间隙(Trabecular Separation,Tb.Sp)第3天,两组Tb.Sp值无统计学差异(P0.05);第7天、14天,激光组Tb.Sp值显著高于对照组(P0.05)。从0天-14天两组Tb.Sp值呈上升趋势,见Fig.12和Table 5、9、10。3.4张力侧牙槽骨骨密度(BMD)第3天,激光组BMD值低于对照组(P0.05);第7天、14天,激光组BMD值显著高于对照组(P0.05)。从0天-14天两组BMD值呈先降低后升高的趋势,见Fig.13和Table 6、9、10。3.5张力侧骨体积分数(BV/TV)第3天、7天,两组BV/TV值无统计学差异(P0.05);第14天,激光组BV/TV值显著高于对照组(P0.05)。从0天-14天两组BV/TV值呈先降低后升高的趋势,见Fig.14和Table 7、9、10。3.6张力侧骨小梁间隙(Tb.Sp)第3天、7天,两组Tb.Sp值无统计学差异(P0.05);第14天,激光组Tb.Sp值显著低于对照组(P0.05)。从0天-14天两组Tb.Sp值呈先升高后降低的趋势,见Fig.15和Table 8、9、10。4组织学观察4.1张力侧第3天时可以观察到两组牙周膜间隙增宽,牙槽骨出现凹坑状吸收,周围可见少量破骨细胞,牙周膜纤维沿着牵引力的方向排列。激光组可见更多的血管扩张充血,少量新生牙槽骨。第7天时,两组血管数量增多,成纤维细胞增多。激光组牙槽骨表面成骨细胞数量显著多于对照组,成骨非常活跃,牙槽骨边缘小的陷窝变平滑,表面骨基质沉积可见新骨形成。第14天时,两组都有明显的新骨形成。激光组的新骨形成多于对照组,见Fig.16、17、18。4.2压力侧第3天时激光组和对照组牙周膜受压变窄、可见牙槽骨浅的吸收陷凹处有破骨细胞出现,激光组破骨细胞较对照组多。对照组牙周膜出现透明样变,血管腔隙变窄。激光组,未见玻璃样变,血管无明显变化。第7天时激光组和对照组牙周膜宽度有所恢复,牙槽骨表面可见大量吸收陷凹。激光组牙槽骨表面破骨细胞数量显著增多,较对照组破骨更活跃,吸收陷凹更多、更深。激光组偶见牙根吸收,仅累及牙骨质,对照组牙根吸收可达牙本质。第14天时激光组破骨细胞明显减少。对照组,透明样变已经基本被清除,可见部分牙根吸收深达牙本质,见Fig.19、20、21。结论:1半导体激光照射可以加快牙齿移动速度。2半导体激光照射可以减少牙齿移动过程中的牙根吸收。3半导体激光照射加速牙齿移动过程中牙槽骨的改建。4 Micro-CT扫描技术可以从三维方向获取精确的牙槽骨微观骨结构参数、牙齿移动距离和牙根长度等数据。
[Abstract]:Objective: with the improvement of living conditions in our country, more and more patients have been treated with orthodontic treatment in recent years, but the course of treatment is more than two years and some even longer. During this period, the patients do not pay attention to oral hygiene and cause gingivitis, periodontitis, caries and other diseases. In the process of orthodontic clinical treatment, the rate of tooth movement is mostly in the mouth cavity. For 1 millimeters per month, in order to accelerate tooth movement, orthodontic scholars have done a lot of research to explore the method of accelerating tooth movement. At present, the methods of accelerating tooth movement are divided into four categories: surgical treatment, gene therapy, drug therapy and physical therapy. The methods of hand operation have certain traumatic and gene therapy. It is not too mature before the drug therapy may cause some side effects. Laser irradiation is one of the physical therapy methods, which mainly accelerates the movement of the teeth by accelerating the formation of osteoclasts and osteoblasts. The semiconductor laser covers the application range of other lasers, with small size, long life and cost. It is more easy to be accepted by patients and doctors as a free and convenient method of accelerating tooth movement, such as low and safe use. It is not clear how the bone structure of the alveolar bone has changed under the irradiation of semiconductor laser. The animal experiments on tooth movement are mostly rats, usually measured with a vernier caliper. In the observation of alveolar bone remodeling and root resorption, the method of histological section is commonly used to observe.Micro-CT, a medical CT with a spatial resolution of up to 1-10 m, which can be used to observe the orthodontic tooth moving distance more comprehensively and accurately from the three-dimensional angle. In this experiment, the velocity of orthodontic tooth movement, the change of the microstructure of the alveolar bone and the absorption of the root were observed by Micro-CT, and the effect of semiconductor laser on the tooth movement was discussed in this experiment, thus providing the reason for the semiconductor laser to accelerate the tooth movement in orthodontic clinic. Reference. Methods: 1 the rat tooth movement model was established by 10% chloral hydroflal abdominal anesthesia (300-350mg/kg), the maxillary incisor and the first molar using the nickel titanium spiral spring added force. Through the maxillary two incisors as the anchorage, the bilateral maxillary first molars moved toward the middle, and each side of the force was 10g. Fig.1.2 semiconductor laser irradiation isoflurane inhalation anesthesia At 1-14 days after the Fig.2. teeth were added, the right maxillary first molar region was irradiated with semiconductor laser (wavelength 980nm, energy density 10J/cm2) on the right side of the maxillary first molar area. The specimens were obtained after the cardiac perfusion of Fig.3 and Fig.4.3 Micro-CT scans in rats. The specimens were scanned with Micro-CT (Sky Scan1076, Billy), and the scanning parameters were 0.7 degrees each time. A total of 180 degrees, 73k V, 142 mu A, the thickness of 18 mu m, and the image size of 1024 x 1024 pixels. The scanning time for each specimen is about 30 minutes. Then the image is reconstructed with the Micro-CT program. Each sample reconfiguration time is about 40 minutes, and the picture is about 1000. The Fig.5. uses CTAn software to carry out the tooth moving distance and the root length. And the measurement of the parameters of the bone structure of the alveolar bone, see Fig.6 and Fig.7.4 to make tissue sections to place the specimen in EDTA solution decalcified, paraffin embedded, make the maxillary first molar as the center, the near far middle direction of the tissue section, the routine HE staining. The statistical analysis of the histological changes of the histological changes under the light microscope uses the statistical software of SPSS 21 for the number of statistical analysis. According to the analysis, the measurement data were expressed with mean standard deviation (Mean + SD). Single factor variance analysis (one-factor ANOVA) was used for the data of normal distribution and homogeneity of variance. The average number of the two groups was compared with independent sample t test. The average number of the four groups was compared with the variance analysis, and the 22 ratio was compared with the LSD test. If the non normal state or the variance was not homogeneous, the non parameter was used. Kruskal-Wallis H test of rank sum test. Taking alpha =0.05 as a test level, P0.05 was statistically significant. Results: 1 tooth movement distance third days, laser group tooth movement distance compared with the control group no statistical difference (P0.05); seventh days, 14 days two groups have significant difference (P0.05), laser group (7d:203.27 + 32.28 u m, 14d:320.80 + 33.82 U) M) was significantly greater than that of the control group (7d:166.93 + 15.46 m, 14d:259.40 + 30.01 m). There was a significant difference in the movement distance between the two groups at 0,3,7,14 days (P0.05). During the 3-7 day, the two groups of tooth movement rates were slower than the 0-3 day; during the 7-14 day, the movement rate of the two groups was faster than that of 3-7 days, and Fig.8 and Table1,9, 10.2 the root resorption of 10.2 days, 7 days, the length of the root of the laser group had no significant difference compared with the control group (P0.05). On the fourteenth day, the length of the root (1.93 + 0.10mm) in the laser group was significantly greater than that of the control group (1.84 0.12mm) (P0.05). The length of the root of the laser group was not statistically different (P0.05) at 0,3,7,14 days (P0.05). Fourteenth days, the control group. Root length less than zeroth days, 3 days of root length (P0.05), Fig.9 and Table 2,9,10.3 alveolar bone structure parameters 3.1 pressure side alveolar bone mineral density (Bone Mineral Density, BMD) third days, two groups of BMD values of no statistical difference (P0.05), seventh days, 14 days, the laser group BMD value was significantly lower than the control group (P0.05) from 0 days two groups decreased two groups decreased values showed a decrease from 0 days of day two group two group values decreased The trend, Fig.10 and Table 3,9,10.3.2 pressure side bone volume fraction (Bone Volume Fraction, BV/TV) third days, two groups BV/TV value of no statistical difference (P0.05); seventh days, 14 days, the laser group BV/TV value was significantly lower than the control group (P0.05). From the two group of 0 days -14 days, the decline trend of the two groups Liang Jianxi AR Separation, Tb.Sp) third days, the two groups of Tb.Sp values were not statistically significant (P0.05); seventh days, 14 days, the laser group Tb.Sp value was significantly higher than the control group (P0.05). From the 0 day -14 day two group Tb.Sp values increased, see Fig.12 and Table 5,9,10.3.4 tension side alveolar bone density (third days), laser group values lower than the control group; seventh days, 14 days, laser The BMD value of the group was significantly higher than that of the control group (P0.05). From the two groups of 0 days -14 days, the BMD value decreased first and then increased, and the tension side bone volume fraction (BV/TV) of Fig.13 and Table 6,9,10.3.5 was third days, 7 days, and the two groups of BV/TV values were not statistically different (P0.05). The fourteenth days, the laser group BV/TV value was significantly higher than the control group (P0.05). Two groups of 0 days from the 0 days decreased first. The trend of lower elevation was found in Fig.14 and Table 7,9,10.3.6 tension side Liang Jianxi (Tb.Sp) third days, 7 days, and there was no statistical difference between two groups (P0.05), and fourteenth days, the Tb.Sp value of the laser group was significantly lower than that of the control group (P0.05). The Tb.Sp value of the two group of 0 days -14 day two increased and then decreased, and the Fig.15 and Table histology observed 4.1 tension. On the side of third days, the gap between the two groups could be observed. The alveolar bone was absorbed by the alveolar bone, a small amount of osteoclasts were seen around the periodontal ligament, and the periodontal ligament was arranged along the direction of traction. The laser group showed more vascular dilatation and congestion and a small amount of new alveolar bone. In the seventh day, the number of blood vessels increased in two groups, and the number of fibroblasts increased. Laser group teeth were increased. The number of osteoblasts on the surface of the alveolar bone was significantly more than that of the control group. The bone formation was very active, the small lacunae on the edge of the alveolar bone became smooth and the surface of the bone matrix was formed to form a new bone. In the fourteenth day, the two groups had obvious new bone formation. The new bone formation in the laser group was more than the control group. The laser group and the control group were seen at the Fig.16,17,18.4.2 pressure side at third days. The compression and narrowing of the membrane showed that there was osteoclast in the absorption notch of the alveolar bone, and there were more osteoclasts in the laser group than the control group. The periodontal membrane of the control group was transparent and narrow. The laser group had no glass change and no obvious changes in the blood vessels. The width of the periodontal membrane was recovered and the surface of the alveolar bone was visible at seventh days. The number of osteoclasts on the surface of the alveolar bone in the laser group increased significantly, and the osteoclasts were more active than the control group. The absorption of the resorption was more and deeper. The laser group found the root absorption, only the cementum, the root absorption of the control group reached the dentin. In the fourteenth day laser group, the osteoclasts of the laser group decreased obviously. The control group, the transparent sample change already basically cleared. Fig.19,20,21. conclusion: 1 semiconductor laser irradiation can accelerate tooth movement speed.2 semiconductor laser irradiation can reduce tooth root absorption in the process of tooth movement, it can reduce tooth movement process,.3 semiconductor laser irradiation can accelerate tooth movement process, and the reconstruction of alveolar bone in the process of tooth movement,.4 Micro-CT scanning technology can be obtained from three dimensional square Accurate alveolar bone microstructure parameters, tooth movement distance and root length data were obtained.

【学位授予单位】：河北医科大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：R783.5

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