【作者】 夏智敏；

【导师】 彭彬；

【作者基本信息】 武汉大学 ， 口腔临床医学， 2005， 硕士

【摘要】 冷牙胶侧方加压充填技术是目前应用最为普遍的一种根管充填技术,而侧方加压器(spreader,以下简称侧压器)则是该充填技术中必不可少的器械。在临床上,通常使用的是不锈钢(SS)侧压器,由于材料的刚性,SS侧压器在弯曲根管中往往不能达到距工作长度1～2mm,而镍钛(NiTi)侧压器由于其韧性和弹性,能沿着弯曲根管的弯曲度进入根管。 本研究通过在树脂模拟根管及离体牙上比较两种侧压器进入弯曲根管的深度,另外,对两种侧压器结合使用不同锥度的牙胶尖充填根管的质量进行分析,探讨其效果,以期为新器械的临床应用和推广提供实验依据。本研究分为三部分。 第一部分 侧方加压器进入弯曲根管深度的实验研究 目的:比较NiTi和SS侧压器进入弯曲根管的深度和所需压力。 材料和方法:选择已预备的树脂模拟根管(35°)20个,随机分成两组,即不锈钢侧方加压器组(SS组)和镍钛侧方加压器(NiTi组),分别测定在空根管内插入两种侧压器达工作长度时所需压力值;放入主牙胶尖,测定侧压器距工作长度3mm时的压力值;放入主牙胶尖,使用15N的压力,记录两种侧压器进入根管的深度。 结果:在空根管中,插入NiTi侧压器所需的平均压力为2.72N,要明显低于SS侧压器的7.48N(p<0.01)。在有主牙胶尖的根管中,NiTi测压器所需的平均压力为36.3 N,要明显低于SS侧压器的48.7N(p<0.01)。15N的压力时,NiTi测压器插入根管的平均深度为13mm;而SS侧压器进入的深度约为12mm(p<0.01)。 第二部分 应用两种锥度主牙胶时侧压器进入根管深度的实验研究 目的:比较在不同弯曲程度的根管应用冷牙胶侧方加压充填技术,使用.02更多还原

【Abstract】 Lateral condensation of cold gutta-percha is widely used throughout the world to fill root canals . The finger spreaders are the instruments which can be used to condense the gutta-percha points. SS spreaders are still used during obturation .Due to their stiffness, stainless steel spreaders may fail to achieve within 1.0mm of working length in curved canals. The greater penetration of NiTi spreaders in cured canals is due to their greater flexibility, which would allow them to follow the curvature of the canal.The purpose of this study was to compare nickel-titanium and stainless-steel spreader penetration in curved canals and plastic blocks, to compare the initial penetration depth of nickel-titanium and stainless steel spreaders during lateral compaction of .02 or .04 tapered master gutta-percha cones and to evaluate the quality of obturation.PART Ⅰ Comparison of NiTi and stainless-steel spreaders penetration in curved canalsAim: To compare nickel-titanium (NiTi) and stainless-steel (SS) spreaders penetration in curved canals.Method: Twenty prepare plastic blocks with a 35°curvature were used for the study. The forces required to inset spreaders to within 1mm of working length in emptycanals and within 3mm of working length in canals containing a master cone were measured. The depths of penetration of spreaders with a master cone in place using 15N force were measured.Result: NiTi spreaders required significantly less force than SS spreaders (2.72N vs 7.48N; P<0.01) in empty canals, as well as in canals containing a master cone (38.3N vs 48.7N; P<0.01). NiTi spreaders penetrated significantly deeper than SS spreaders (13mm vs 12mmm; P<0.01) when using the same force.PART II Comparison of Nickel-Titanium and Stainless-steel Spreader Penetration of .04 and .02 Taper Gutta-perchaAIM: To compare the initial penetration depth of nickel-titanium (NiTi) and stainless-steel(SS) spreader during lateral compaction of .04 and .02 tapered master gutta-percha cones.Method: Thirty-eight extracted mandibular premolars with a single canal were divided into two experimental groups by degree of curvature for comparison. Four groups of measurements were obtained within each canal. The groups consisted of: (a) NiTi spreader with size 40/.02 taper master cone; (b) NiTi spreader with size 40/.04 taper master cone; (c) SS spreader with size 40/.02 taper master cone; (d) SS spreader with size 40/.04 taper master cone.Result: NiTi spreaders penetrated to a significantly greater depth than SS spreaders (0.48mm vs 1.43mm ) using .02 tapered gutta-percha in canal curvatures greater than 20 degrees and when using .04 tapered gutta-percha regardless of 0 to 20 degrees (1.95mm vs 2.79mm). No significant difference occurred between NiTi and SS spreader penetration using .02 tapered gutta-percha in canal curvatures of 0 to 20 degrees (p>0.05).PART HI Comparison of Laterally Condensed .04 and .02 TaperedGutta-Percha in VitroAIM: To compare the quality of the seal in canals prepared in a standardized manned and obturated with a .04 or a .02 tapered gutta-percha master cone using lateral condensation.Method: Eighty extracted mandibular premolars with a single canal were divided into two experimental groups by degree of curvature for comparison. The Canals were instrumented by NiTi ProFile and obturated with cold laterally condensed gutta-percha. Horizontal sections were cut 2 and 4mm from the apex. The area of the canal and gutta-percha in cross-sections was measured using an image analysis programme.Result: In canal curvatures greater than 20 degrees the levels of 2mm have significantly more gutta-percha fill with .02 tapered gutta-percha using NiTi spreaders. In canal curvatures of 0 to 20 degrees the levels of 2mm have significantly more gutta-percha fill with .04 tapered gutta-percha compared with .02 tapered gutta-percha between NiTi and SS spreaders. No significant difference occurred using .02 tapered gutta-percha (p>0.05). At 4mm level there was no significant difference between .04 and .02 tapered gutta-percha (p>0.05).Conclusion: The NiTi spreaders penetrated to a significantly greater depth and required significantly less force than SS spreaders in cured canals .The area occupied by gutta-percha was significant greater for filling with .04 tapered gutta-percha compared with .02 tapered gutta-percha.更多还原