【作者】 焦珊；

【导师】 王成坤；

【作者基本信息】 吉林大学 ， 口腔临床医学， 2012， 硕士

【摘要】 目的：测量IV型上颌第一前磨牙原始直径及锥度，为临床根管预备及器械选择提供依据。材料方法：收集40-60岁中国吉林地区离体上颌第一前磨牙共40例，经预处理后，采用显微CT进行断层扫描，将扫描得到的图像导入MIMICS16.0软件系统，进行根管各段直径测量，依据锥度计算公式为：C＝（D－d）/l，推算出根管各段锥度。结果：①Ⅳ型上颌第一前磨牙颊侧及腭侧根管直径，均为颊舌向直径大于近远中向直径，颊舌向直径由根尖孔至根冠部逐渐增大。两组对比除根管尖段与根尖孔段统计学无明显差异外（P＞0.05），余统计学差异明显（P＜0.05）；近远中向直径由根尖孔至根冠部逐渐增大，两组对比除根管尖段与根尖孔段统计学无明显差异外（P＞0.05），余统计学差异明显（P＜0.05）。②颊侧与腭侧根管比较：颊舌向与近远中向直径均为颊侧根管大于腭侧根管，两者之间统计学差异明显（P＜0.05）。③Ⅳ型上颌第一前磨牙颊侧及腭侧根管锥度，均为颊舌向根冠段锥度大于根中段、大于根尖段，两两对比均统计学差异明显（P＜0.05），根尖段与根中段对比两者统计学无明显差异（P＞0.05）；近远中向根冠段锥度大于根中段，根中段大于根尖段，但统计学无明显差异（P＞0.05）。即颊舌向锥度大于近远中向锥度；颊舌向根冠段锥度明显大于根中段及根尖段，根尖段到根中段无明显变化，近远中向根管锥度从根尖到根冠段无明显变化。结论：上颌第一前磨牙IV型中颊、腭侧根管的形态均与Ⅰ型较为相似。颊侧根尖孔直径较腭侧大，临床工作中应选用对应号数器械分别预备。双根均为非连续锥度，预备中应分段预备。两种机动镍钛根管器械成形能力的比较研究目的：通过对两种镍钛根管器械预备前后根管各段横截面的比较，分析根管预备效果及记录预备时间，从而为临床中根管预备器械的选择提供实验依据。材料方法：将离体上颌第一前磨牙共40例进行随机分为两组：Mtwo组（M组），Revo-S组（R组）。每组各20例。M组：采用标准法，用15#C型先锋锉疏通根管，测量工作长度，将颊、腭侧根管预备至40#/0.05。 R组：先用SC1敞开根管冠部2/3，使用15#C型先锋锉通畅根管，测量根管工作长度，然后分别使用SC2、SU、AS30、AS35、AS40采用冠向下法，将颊、腭侧根管预备至AS40。两组均反复提拉，使根管壁光滑，根管通畅。预备过程中，每更换一次器械，使用lml3%过氧化氢液和lml5.25%次氯酸钠交替进行冲洗，预备完成后，用2ml生理盐水冲洗。之后采集预备后根管各横截面的图像与预备前图像重叠并进行分析，记录各段横截面面积差值、根管中心偏移量及偏移方向。结果：M组和R组在根冠处横截面的根管偏移量的比较有显著统计学差异（P<0.05），在根中、根尖、根尖孔处横截面根管偏移量两两比较均无明显统计学差异（P＞0.05），R组预备时间较M组短。结论：Revo-S与Mtwo都有较好的根管成形能力，Mtwo能更好的维持根管原有走向。Revo-S更适合锥度变异性较大的根管，同时也节约了根管预备的操作时间。更多还原

【Abstract】 AIM: Measuring the original diameter and taper of the type IV maxillaryfirst premolars, and provide the basis and device selection for the clinical rootcanal preparation.MATERIALS AND METHODS: Collection a total of40samples maxillaryfirst premolars of age40-60-year-old from Jilin, China.After pretreatment andMicro-CT tomography,get the maxillary premolar image to import MIMICS16.0software system. Measure the diameter of every root canal segment. Accordingto the formula: C＝（D－d）/l，calculate the taper of root canals.RESULTS:①The buccal and palatal lateral root canal diameters of type Ⅳ maxillaryfirst premolar are all bucco-lingual diameter greater than the mesio-distaldiameter and bucco-lingual diameter gradually increases from the apical to thecoronal. There was significant difference (P＜0.05) except between the apicaland foramen; similarly, mesio-distal diameter gradually increases from theapical to the coronal. There was aslo significant difference (P＜0.05) exceptbetween the apical and foramen.②Comparison of the buccal and palatal root: the mesio-distal and thebucco-lingual diameters were buccal’s far bigger than palatal’s.There was significant differences between the every two comparison (P＜0.05).③The buccal and palatal lateral root canal taper of type Ⅳmaxillary firstpremolar in bucco-lingually are coronal1/3greater than the middle1/3andapical1/3. There was significant differences between the every two comparison(P＜0.05), while there without significant difference between the apical1/3andmiddle1/3(P＞0.05); In mesio-distally, the taper of coronal1/3was greaterthan the middle1/3and middle1/3was greater than the apical1/3,however therewas no significant difference (P＞0.05). That is, for the taper, bucco-lingualwas greater than the mesio-distal’s; coronal1/3greater than the middle1/3andapical1/3obviously. There was no significant changes from the apical1/3to themiddle1/3, also from the apical1/3to the coronal1/3in mesio-distal.CONCLUSIONS: For type Ⅳ maxillary first premolar, root canalmorphology of double root is similar to the single’s. Buccal lateral apicaldiameter greater than the palatal’s. It should be use the corresponding numbersof instruments espectively to prepare root canal in clinical. The two root bothhave non-continuous taper, and it ought to prepare segmented.Part II:Comparing study on the effect of two nickel-tianium rotaryinstruments in root canal preparationAIM: Comparison of the before and after preparated root canalcross-section by the two instruments. Analysis the effects of the root canal preparation, thus provide the experimental basis for the choice of clinical rootcanal preparation equipment.MATERIALS AND METHODS: Take the total of40specimens maxillary firstpremolar and random divided into2groups of20samples each: Mtwo (groupM), Revo-S (group R). Group M: canals were prepared by using a standardtechnique, dredgethe root canal with15#C file firstly, measuring the length ofthe root canal, then prepared the buccal and palatal to40#/0.06.Group R: useSC1open the crown2/3of the root canal, dredge the root canal with15#C file,measuring the length of the root canal. Then use SC2、SU、AS30、AS35、AS40with crown-down preparation technique prepared the buccal and palatal toAS40.Repeatedly pulling and make root canal wall smooth, and unobstructed.After each instrument, the root canals were flushed with1ml of a3%H2O2、1mlof a5.25%NaOCl solution and at the end of instrumentation with2mL of saline.Collected cross-section images after prepared, analyze the overlap images beforeand after preparation. Then acquisition images of cross-section after root canalpreparation overlap analysis with the preparation before. Record the differencebetween the cross-section area、root canal center offset and offset direction.RESULTS: There was significant differences in cross-section coronal1/3of group M and group R (P＜0.05), while without significant differences incross-section middle1/3, apical1/3, foramen1/3(P＞0.05). Preparation time forthe group R is shorter than the group M.CONCLUSIONS: Revo-S file and Mtwo file have a good root canal shaping ability, Mtwo has a better ability to maintain the original direction of theroot canal. Revo-S is more suitable for the root canal with variability taper, alsosave the time of root canal preparation meanwhile.更多还原