ChemFil封闭髓腔入口效果的研究

目的：研究ChemFil作为暂封材料封闭髓腔入口的效果。方法：30个磨牙随机分为两组，每组15个，开髓后分别使用牙胶和ChemFil作为暂封材料封闭窝洞。置入2％亚甲蓝溶液中，3d后显微镜下观察染料渗入洞壁的深度并评分。结果：牙胶组15个牙中有12个完全渗漏至髓腔，3个评为2分。ChemFil组有7个完全没有渗漏，6个评为1分，2个评为2分。两组的封闭性能存在显著性差异。结论：ChemFil是一种封闭性能较好的暂封材料。     

三种充填技术根管封闭能力的研究

目的:利用葡萄糖定量法检测根管微渗漏模型,评价侧向加压充填技术、垂直加压充填技术及固核载体充填技术对根管微渗漏的影响.方法:选取71颗直根管上前牙,根管预备后随机分为7组,A组(14颗)用热牙胶垂直加压加AH Plus充填;B组(8颗)仅用热牙胶垂直加压充填;C组(13颗)用侧方加压加AH Plus充填;D组(8颗)仅用侧方加压充填技术;E组(11颗)用Thermafil加AH Plus充填;F组(7颗)仅用Thermafil充填;G组(10颗)为阴性对照组,用粘蜡充填根管.牙根外表面、根管口及根尖孔处涂二层指甲油.于第7 d、14 d、21 d、28 d用葡萄糖氧化酶法检测从冠方向根方漏出的葡萄糖量.结果:采用重复测量方差分析,发现第7 d、14 d、21 d、28 d A、C组及C、E组微渗漏值有显著性差异(P＜0.001),但A、E组无显著性差异(P＞0.05).各时间点C、D组比较有显著性差异(P＜0.001),但A、B组与E、F组比较无显著性差异(P＞0.05).第7 d、14 d及第21 d、28 d各组内比较无显著性差异(P＞0.05),但各组第14 d与第21 d比较有显著性差异(P＜0.05).结论:侧方加压充填技术封闭根管的能力优于垂直加压充填技术及固核载体充填技术,而后两种充填技术封闭根管的能力相当.     

An In Vitro Investigation of a Comparison of Bond Strengths of Composite to Etched and Air-Abraded Human Enamel Surfaces

PURPOSE: The purposes of the study were to measure the tensile bond strength of composite resin to human enamel specimens that had been either etched or air-abraded, and to compare the quality of the marginal seal, through the assessment of microleakage, of composite resin to human enamel specimens that had been either etched or air-abraded. MATERIALS AND METHODS: Thirty mandibular molar teeth were decoronated and sectioned mesio-distally to produce six groups, each containing ten specimens that were embedded in acrylic resin using a jig. In each of the four treatment groups, the specimen surfaces were treated by either abrasion with 27 or 50 microm alumina at 4 mm or 20 mm distance, and a composite resin was bonded to the treated surfaces in a standardized manner. In the two control groups the specimens were treated with 15 seconds exposure to 36% phosphoric acid gel and then similarly treated before being stored in sterile water for 1 week. All specimens were then subjected to tensile bond strength testing at either 1 or 5 mm/min crosshead speed. For the microleakage study, the degree of dye penetration was measured 32 times for each treatment group, using a neutral methylene blue dye at the interface between composite and either 27 or 50 microm air-abraded tooth structure or etched enamel surfaces. RESULTS: The mean bond strength values recorded for Group 1 (phosphoric acid etch, 5 mm/min crosshead speed) was 25.4 MPa; Group 2 (phosphoric acid etch, 1 mm/min), 22.2 MPa; Group 3 (27 microm alumina at 4 mm distance), 16.8 MPa; Group 4 (50 microm alumina at 4 mm distance), 16.9 MPa; Group 5 (27 microm alumina at 20 mm distance), 4.2 MPa; and for Group 6 (50 microm alumina at 20 mm distance) 3.4 MPa. An analysis of variance (ANOVA) demonstrated significant differences among the groups, and a multiple comparison test (Tukey) demonstrated that conventionally etched specimens had a greater bond strength than air-abraded specimen groups. No significant difference in dye penetration could be demonstrated among the groups (p= 0.58). CONCLUSIONS: Composite resin applied to enamel surfaces prepared using an acid etch procedure exhibited higher bond strengths than those prepared with air abrasion technology. The abrasion particle size did not affect the bond strength produced, but the latter was adversely affected by the distance of the air abrasion nozzle from the enamel surface. The crosshead speed of the bond testing apparatus had no effect on the bond strengths recorded. The marginal seal of composite to prepared enamel was unaffected by the method of enamel preparation.     

新型纳米羟基磷灰石(n-HA)糊剂封闭根尖性能及其对病原菌抗菌活性的体外实验

目的：研究新型纳米羟基磷灰石根管充填糊剂（n-HA）、AH-Plus根管封闭剂的根尖封闭性能以及二者对感染根管优势菌牙龈卟啉单胞菌（Porphyromonas gingivalis,Pg）、具核梭杆菌（Fusobacteria nu-cleatum,Fn）、中间普氏菌（Prevotalla intermedius,Pi）生长的影响。方法：实验一34个离体单根管牙随机分为4组,用镍钛旋转器械Protaper预备根管,阳性对照（2个）、阴性对照（2个）、2个实验组（各15个）,分别用新型n-HA、AH-plus根充糊剂加牙胶尖以冷侧压法根充恰填,染料渗入法检查根尖微渗漏。实验二选用Pg、Fn、Pi作为实验菌株,常规打孔法测定新型纳米羟基磷灰石根管充填料、AH-Plus根管封闭剂的抑菌效果。结果：所有根充糊剂充填后根尖部位均有微渗漏,AH-plus组的微渗漏值低于n-HA组,2组结果间无统计学意义（P〉0.05）。n-HA与AH-Plus糊剂对Pg、Fn、Pi均有一定的抑菌作用,但n-HA的抑菌作用明显强于AH-Plus。结论：2种根充糊剂充填后都不能完全封闭根尖孔,AH-plus根充糊剂的根尖封闭性优于n-HA组。n-HA根充糊剂具有较理想的抑菌效果。     

Comparison of Apical Microleakage of Lateral Compaction Technique and Vertical Compaction Technique

目的:首次采用葡萄糖渗漏模型(GPM)对比研究在有根充糊剂和没有根充糊剂的情况下垂直加压充填技术和侧向加压充填技术对根管微渗漏的影响。方法:选取53颗直根管上前牙,根管预备后随机分为5组,A组(14颗)用热牙胶垂直加压加AHPlus充填,B组(8颗)仅用热牙胶垂直加压充填,C组(13颗)用侧方加压加AHPlus充填,D组(8颗)仅用侧方加压充填技术,E组10颗)为阴性对照组,用粘蜡充填根管,牙根外表面及根尖孔处涂二层指甲油。于第7、14、21、28天用葡萄糖氧化酶法检测从冠方向根方漏出的葡萄糖量。结果:采用重复测量方差分析,发现第7、14、21、28天A、C组微渗漏值有显著性差异(P<0.001)。各时间点C、D组比较有显著性差异(P<0.001)。第7、14天及第21、28天各组内比较无显著性差异(P>0.05),但各组第14天与第21天比有显著性差异(P<0.05)。结论:侧方加压充填技术封闭根管的能力优于垂直加压充填技术及固核载体充填技术,而后两种充填技术封闭根管的能力相当。     

Er、Cr:YSGG激光根管内照射对根管封闭效果的影响

目的:探讨常规根管预备后使用不同能量的Er、Cr:YSGG激光进行根管内照射对根充后根管封闭效果的影响。方法:选择新拔除的单根管牙105颗,分成7组,每组15颗牙。切除牙冠后,常规进行根管预备。第1组不进行任何处理,作为阳性对照组;第2组为1W、有水激光照射;第3组为1W、无水激光照射;第4组为2W、有水激光照射;第5组为2W、无水激光照射;第6组为3W、有水激光照射;第7组为3W、无水激光照射。根充后进行根尖微渗漏检测,评估根管封闭效果。采用单因素方差分析(Anova)进行多组间总体均数比较,q检验进行组间比较。结果:除3W无水组外,其他各激光组与对照组相比,根尖微渗漏深度均有显著性差异(P<0.05);其中1W无水组与对照组相比具有高度显著性差异(P<0.01)。结论:较低能量(除外3W、无水)Er、Cr:YSGG激光进行根管内照射,能够有效提高根管充填后的封闭效果,其中1W、无水激光照射时根管封闭效果最好。     

Dentin adhesion and microleakage of a resin-based calcium phosphate pulp capping and basing cement

An experimental resin-based bioactive calcium phosphate cement, intended as a pulp capping and basing material, was evaluated for dentin shear bond strength and microleakage. The interfacial morphology was examined by scanning electron microscopy (SEM). For microleakage, dentin cavities without (Group A) or after (Group B) acid etching were restored with the calcium phosphate cement. A resin-based calcium hydroxide (VLC Dycal; Group C) was used as control material according to the manufacturer's instructions. After water storage and thermocycling, the microleakage was scored using a AgNO(3) staining procedure. For the shear bond strength, flat exposed dentin surfaces were treated as for the microleakage test. Metal irises pressed against the dentin surface were filled with the cements, which were photocured. Both tests were carried out after 1 wk. While acid etching did not result in significantly greater microleakage, it led to higher shear bond strength, and allowed, as shown by SEM, the formation of a hybrid layer and resin tags. Both groups treated with the calcium phosphate cement had significantly lower microleakage scores and higher mean shear bond strength values than the groups treated with the control material.     

几种市售商品充填材料密合度的实验研究

选用几种市售牙体充填复合树脂和玻璃离子水门汀充填Ⅴ类洞(龈壁由牙骨质和牙本质组成),采用染色法观察其边缘微漏的离体牙实验。发现不同充填材料存在不同程度的边缘微漏,酸处理洞缘可显著降低边缘微漏(P<0.05),窝洞的牙釉质壁渗漏显著低于牙骨质壁渗漏(P<0.01)。实验结果提示,充填材料的粘附性能,窝洞边缘的位置以及酸处理技术,都将影响牙体充填的治疗效果。     

不同窝洞处理剂对银汞合金充填微渗漏的影响

目的：探讨减少银汞合金充填后边缘微渗漏的有效方法。方法：选择无龋的离体磨牙４８个，随机分为４组，每个牙分别制面洞、颊面颈１／３洞。比较几种窝洞洞壁处理后对微渗漏的影响。结果：银汞合金充填１个月后，１０％ＥＤＴＡ处理窝洞组、１０％ＥＤＴＡ加护洞漆组与空白组之间的边缘微渗漏无明显差异，而含３％ＦｅＣｌ３的１０％枸橼酸（１０－３液）处理加银汞合金粘结剂组则明显减少微渗漏。结论：离体牙实验证明银汞合金粘结修复可明显减少银汞合金充填术后的微渗漏     

SOFT-START光聚合技术对复合树脂充填体边缘微渗漏影响的实验研究

目的 :探讨SOFT -START光聚合技术对光固化复合树脂充填后边缘微渗漏的影响 ,为该技术的推广应用提供实验依据。方法 :选择因正畸需要拔除的第一前磨牙的志愿者 2 0人共 80个牙 ,随机分成 4组 ,每组 2 0个牙。在每个牙牙合面中央制备Ⅰ类洞 ,常规酸蚀、冲洗、吹干、涂布粘接剂。 1组、2组 :充填Z2 5 0树脂 ,3组、4组 :充填Charisma树脂 ;1组、3组采用传统光固化方式固化 ( 75 0W /cm2 × 40s) ;2组、4组 :采用SOFT -START光聚合技术固化 ( 2 0 0W /cm2 × 10s ,75 0W /cm2 × 3 0s)。所有牙充填后在口内留置 7d后拔除 ,0 .5 %品红溶液渗入法染色 ,体视镜下观察 ,判定微渗漏程度。结果 :采用SOFT -START光聚合技术组充填体微渗漏程度显著低于传统固化方式组。结论 :SOFT -START光聚合技术有助于减少光固化复合树脂的聚合收缩 ,可提高充填体边缘封闭性 ,减少微渗漏产生