Bacterial microleakage of Cavit, IRM, and TERM.

In this in vitro study, a model system was developed and tested to evaluate the sealing ability of temporary restorative materials used in endodontic access preparations. The materials studied, Cavit, IRM, and TERM, were tested on 40 premolars against a known bacterial species, Streptococcus sanguis. The leakage of bacterial cells was checked 4 and 8 days after initial immersion in the culture. Thermocycling was introduced on the fourth day. After 8 days the cement thicknesses were measured after the teeth had been longitudinally sectioned. Before and after thermocycling, IRM was less leakproof than Cavit (p < 0.05) and TERM (p < 0.05). Thermocycling aggravated percolation in the case of IRM, and decreased the tightness of Cavit, whereas TERM remained leakproof. The thicknesses were as follows: Cavit, 3.73 mm; IRM, 3.45 mm; and TERM, 5.49 mm. There was no statistically significant relationship between thickness and tightness.     

Bacterial microleakage of Cavit, IRM, TERM, and Fermit: a 21-day in vitro study

The aim of our study was to evaluate the leakage of four cements (Cavit, IRM, TERM, and Fermit) using a two-compartment model system and Streptococcus sanguis as bacterial marker. Access cavities in premolars were filled with cement and the teeth immersed in culture medium in the model system. Half of the teeth were thermocycled on day 2. Bacterial percolation into the upper compartment was measured at regular intervals (days 2, 7, 14, and 21). Cement thickness was measured at the end of the study. In the nonthermocycled group, Cavit was more leakproof than the other cements at day 2 (p = 0.011), than TERM and IRM at day 7 (p = 0.043). Fermit was more leakproof than IRM at day 7 (p = 0.043). In the thermocycled group, Cavit was more leakproof than the other cements at day 7 (p = 0.041). Thermocycling did not significantly affect leakage. Cement thickness averaged 4.1 mm and did not significantly affect leakage. These results should be considered when using cements as temporary fillings.     

In vitro comparison of coronal microleakage between Resilon alone and gutta-percha with a glass-ionomer intraorifice barrier using a fluid filtration model

The prevention and control of coronal microleakage is critical for successful endodontic outcomes. The purpose of this study was to compare coronal microleakage between Resilon alone and gutta-percha with a glass ionomer intraorifice barrier using a fluid filtration model. Thirty-four extracted human teeth were decoronated, prepared to a standardized length of 16 mm, and instrumented to a .06 taper ISO size 40. After removal of controls, the remaining roots were randomly divided into two equal groups of 15 and obturated with either Resilon alone or gutta-percha with a 2-mm glass-ionomer intraorifice barrier. After set of the sealers, the teeth were evaluated for microleakage using a fluid filtration model. A Student t test found significantly less leakage for the gutta-percha/glass-ionomer intraorifice barrier group than the Resilon alone group (p = 0.008).     

不同桩核冠向微渗漏的比较研究

目的 研究铸造镍铬合金桩核、黏接银汞桩核、传统银汞桩核和纤维树脂桩核的冠向微渗漏情况,为临床桩核的选择提供依据.方法 选择60颗新拔除的人上颌磨牙,随机分为6组,其中4组分别制作铸造镍铬合金桩核、黏接银汞桩核、传统银汞桩核和纤维树脂桩核,另2组分别为阳性和阴性对照,然后浸入印度墨水中1周,评价不同桩核的冠向微渗漏情况.结果 4个实验组微渗漏明显小于阳性对照组(P ＜ 0.05);纤维树脂桩核组和黏接银汞桩核组微渗漏明显小于传统银汞桩核组和铸造镍铬合金桩核组(P ＜ 0.05).结论 各种桩核修复都可在一定程度上减小微渗漏,其中黏接银汞桩核和纤维树脂桩核修复更为有效.     

Microleakage of Cavit, CavitW, CavitG and IRM by impedance spectroscopy

The aim of this study was to quantify the sealing ability of four temporary filling materials over 9 days using a new electrochemical technique. Fifty-two extracted human maxillary bicuspids were selected and prepared for the measurements. They were divided into four groups of 12 teeth each, in addition to two positive and two negative controls. After preparation of the endodontic access cavity the sealing ability was registered. After a randomization procedure one group was obturated with IRM, another group with Cavit, a third group with CavitW and the last group with CavitG. The sealability was measured just after obturation (time 0) and after days 1, 2, 3, 4, 7 and 9. The results showed that the IRM group was significantly more watertight than the different Cavit formulations. Throughout the experiment no significant difference was noticed between the Cavit and CavitW groups (P < 0.05). The CavitG group was significantly less watertight throughout the measurements (P < 0.05).     

根管内屏障对根管治疗牙冠方微渗漏影响的体外研究

完整单根管前磨牙42颗,截去牙冠,常规根管治疗,随机分为4组,2%亚甲基蓝染色,2周后取出,制作透明样本,体视显微镜观察并测量样本微渗漏长度,并对数据进行统计学分析。结果显示阴性对照组未见染料渗入根管,阳性对照组见整个根管被染色(单因素方差分析,P<0.001),微渗漏长度的均数和置信区间由GP(4.80±0.54,4.42～5.19)、ZPC(3.39±0.65,2.92～3.85)、Filtek Z350(2.07±0.27,1.87～2.27)至Fiju VⅡ(1.68±0.15和1.57～1.79)呈递减趋势,两两比较,除Filtek Z350与F ijuVII间差异无统计学意义外(P>0.05),其余各组间差异均有统计学意义(P<0.05)。说明根管内屏障能够提高根管治疗牙冠方封闭能力;Filtek Z350、Fuji VⅡ可作为根管内屏障材料应用于临床。     

暂时封固对根管治疗牙冠方微渗漏影响的体外研究

目的 评价不同暂封材料、暂封方式对根管治疗牙冠方微渗漏的影响,探讨根管治疗牙冠方微渗漏发生情况及与时间的关系.方法 收集离体牙,常规根管治疗后随机分组,2%亚甲基蓝染色,制作透明样本,体视显微镜下观察样本微渗漏情况,根据染料渗漏最大长度评分,收集数据并进行统计分析.结果 暂封1、4 周时,Cavit-G和Caviton微渗漏评分低于氧化锌丁香酚水门汀(ZOE);暂封2 周,Caviton微渗漏评分低于ZOE和Cavit-G.ZOE作为暂封材料,两种方式样本微渗漏评分比较差异无统计学意义(P > 0.05);暂封1 周时,Cavit-G和Caviton直接与间接暂封微渗漏评分差异无统计学意义(P > 0.05),暂封2周,Cavit-G和Caviton微渗漏评分差异无统计学意义(P > 0.05).随暂封时间的延长,3种材料的微渗漏差异有统计学意义(P < 0.05).结论 Caviton冠方暂封效果最好,其次为Cavit-G,ZOE最差;间接暂封明显加速Cavit-G和Caviton暂封样本冠方微渗漏;Caviton和 Cavit-G用于暂封的适宜时间为2周,ZOE为1周.     

Microbial leakage of Cavit, IRM, and Temp Bond in post-prepared root canals using two methods of gutta-percha removal: an in vitro study

The aim of this study was to evaluate the integrity of the coronal seal of Temp-Bond and compare it to Cavit and IRM after post space preparation using S. faecalis as a microbial tracer. In addition, the affect of two methods of gutta percha removal on the apical seal of root canal fillings was also evaluated. Forty extracted human single rooted teeth were prepared chemomechanically and obturated with gutta percha and AH26 sealer cement using the lateral cold condensation technique to a standardized working length of 15 mm. About 10 mm of the coronal gutta-percha was removed with either Peeso-reamer or a hot plugger. The roots were divided into three experimental groups of 10 roots and a control group. Each experimental group was subdivided equally into two groups of 15 each according to the method of post space preparation. Cavit, IRM, and Temp-Bond were used to seal the access opening. Each root was fixed in a cuvette containing Tryptic Soya Broth which, covered 2 mm of the root apex. Bacterial suspension was introduced through pipette. Fresh bacterial suspension was added every week, and the system was monitored daily for the growth of microorganisms for a period of one month. The results showed there was no significant difference in terms of coronal leakage between the three coronal materials used (P=0.478), but the methods of gutta-percha removal did have an impact on the apical leakage (P=0.047). The mean value showed the Peeso-reamer provided less leakage compared to using a hot plugger during the 30-day experimental time period. It was concluded the temporary type of coronal seal of endodontically treated teeth will not prevent coronal leakage if left for a long period of time. In addition, permanent cementation of the post with the coronal restoration should be carried out as soon as possible to prevent recontamination of the root canal.     

不同桩核和粘接系统冠向微渗漏的实验研究

目的:通过染色法测量冠向微渗漏的大小,比较不同桩核及粘接剂的冠向封闭能力.方法:选择50 颗离体下颌单根管前磨牙,使用ProTaper镍钛锉冠向下法进行根管预备.样本随机分为6 组.A组为暂封组、B组为树脂粘接纤维桩核组, C组为树脂粘接铸造金属桩核组, D组为磷酸锌粘固铸造金属桩核组, E组为阳性对照组,F组为阴性对照组.除阳性对照组,所有根管侧向加压法充填.桩道预备和桩核修复后印度墨水染色1 周,透明处理,体视显微镜下观察冠向染料渗入情况.结果:暂封组冠向微渗漏值明显大于各桩核修复组(P<0.05);树脂粘接的纤维桩组与金属桩组之间无统计学差异(P>0.05);树脂粘接的纤维桩组和金属桩组的冠向微渗漏值均明显小于磷酸锌粘固组(P<0.05).结论:桩核修复可以减小冠向微渗漏,树脂粘接材料封闭效果更好.     

An in vitro study of coronal microleakage in root-canal-treated teeth restored by the post and core technique

The aims of this study were to compare coronal microleakage around cast and prefabricated post and cores and to examine the coronal seal achieved by temporary post crowns. Thirty extracted, single-rooted, human teeth were prepared chemomechanically, root filled with gutta-percha and sealer and prepared for a standard post. Three groups, each of 10 teeth, were restored with either: (i) cast post and cores cemented with zinc phosphate cement; (ii) prefabricated posts and composite cores cemented with a composite luting cement; or (iii) temporary post crowns cemented with a temporary zinc oxide-eugenol cement. The teeth were thermocycled and placed in Indian ink for 1 week, then demineralized and rendered transparent. Linear coronal dye penetration around the posts was measured and recorded. Results indicated that while cast post and cores and prefabricated posts and composite cores produced a good seal, leakage was significantly greater with temporary post crowns ( P < 0.05). It is concluded that to prevent re-infection of the root canal system, it may be preferable to restore the tooth immediately with a prefabricated post and composite system rather than place a temporary post crown and subsequently a cast post and core.     

An in vitro study of coronal microleakage in endodontically-treated teeth restored with posts

Coronal microleakage has received considerable attention as a factor related to failure of endodontic treatment and much emphasis is placed on the quality of the final restoration. Posts are frequently used for the retention of coronal restorations. These can be custom-made or prefabricated. Many authors have examined coronal microleakage with respect to gutta-percha root fillings and plastic coronal restorations, but few have investigated the coronal seal afforded by various post systems. The seal provided by a cemented post depends on the seal of the cement used. The purpose of this study was to compare coronal microleakage around cast and prefabricated posts using a dye-penetration method. Sixty extracted single-rooted human teeth were chemomechanically prepared. The root canals were filled with gutta-percha and sealer and they were then prepared for standard posts. Six groups, each of 10 teeth, were restored with either cast post or prefrabricated post. The posts were cemented with either glass ionomer cement (GIC), Variolink II or Durelon. The teeth were thermocycled and placed in Indian ink for one week. They were then demineralised and rendered transparent. Linear coronal dye penetration around the post was measured and compared. The least dye-penetration was observed in roots restored with a cast post and Variolink II. Dentatus posts demonstrated the most microleakage. It appears that the dentine-bonding cements have less microleakage than the traditional, non-dentine-bonding cements and adaptation of the post with the canal may be more important than the cement used.     

四种光固化复合树脂修复物边缘微渗漏的体外试验研究

目的:比较4种光固化充填材料修复体边缘微渗漏.方法:在新鲜拔除的40个人前磨牙的颊侧牙颈部制洞,将牙齿分为4组,每组10个.分别充填4种修复材料Restorative Z-350、Z-100(3M),Chafisma(Dentsply),Durafill(Kulzer)经冷热交替试验(4～60℃,循环600次),采用10 g/L碱性品红染料渗入法,在体视显微镜下观察修复体与牙体洞壁间边缘微渗漏.结果:4种材料中3M-Z350微渗漏最小,Durafill最大,DurafiU与其他3组相比有显著性差异(P＜0.05);3M-Z100和Chrisma无显著性差异(P＞0.05);3MZ350与其他3组相比有显著性差异(P＜0.01).结论:3M-Z350可能是临床修复牙体缺损的较好材料.     

In vitro microleakage study of a condensable and flowable composite resin

The aim of this study was to evaluate the in vitro microleakage of a condensable composite resin recommended for Class II restorations with and without a flowable composite resin as a liner. There were statistically significant differences between all groups and between individual groups (p < 0.05). The results showed significantly less microleakage in teeth restored with flowable composite resin underneath a condensable composite resin.     

Longitudinal study on microleakage of three root-end filling materials by the fluid transport method and by capillary flow porometry

AIM: (i) To compare the root-end sealing ability of IRM Caps (IRM), Fuji IX Capsules (Fuji IX) and Pro Root MTA Tooth-Coloured Formula (MTA) in teeth obtained from cadavers. (ii) Further research on leakage study methodology by means of comparison of the fluid transport method (FTM) and capillary flow porometry (CFP). METHODOLOGY: Root canal treatment was performed on 33 cadaver teeth in situ 2 weeks prior to root resection and ultrasonic retropreparation (S12/90 degrees D-tip on Suni-Max), after which the teeth were retrieved from the cadavers. Two teeth were kept as positive and negative controls. The other teeth were divided in three different groups at random, with each group receiving one of the retrofill materials. Retrofills were exposed to water 5 min after placement. The teeth were stored at 37 degrees C for 12 h after which the root filling was removed. Microleakage (L in microL day(-1)) was measured for 24 h under a pressure of 1.2 atm using FTM and recorded as L = 0, 0 < L < or = 10, L > 10. The measurements were repeated after 1 and 6 months. After 6 months, leakage was also assessed by CFP in order to measure through pores and their diameters. Results were analysed statistically using nonparametric Kruskal-Wallis and Mann-Whitney U-tests, and Spearman correlation coefficients between the results of both methods were calculated. The level of significance was set at 0.05. RESULTS: (i) A statistically significant difference could be demonstrated between Fuji IX and IRM at 1 month with FTM. FTM revealed a significant difference between Fuji IX and the other materials at 6 months, whereas CFP did not. However, using both methods, Fuji IX showed the best result. (ii) When comparing both techniques, CFP demonstrated through pores in all teeth, whereas with FTM in only 14 of the 31 teeth could through pores be demonstrated. A positive correlation between both methods was demonstrated. CONCLUSIONS: Under the conditions of this study (i) the conventionally setting glass-ionomer cement Fuji IX showed the best results when used as a root-end material and (ii) CFP appeared to be a useful method for leakage evaluation of through pores in endodontics.     

In vitro, relative microleakage of five restorative systems

The purpose of this study was to determine the relative microleakage of five restorative systems when bonded to dentine/cementum. For the microleakage determination Class V cavity preparations were prepared on the facial surfaces of 65 teeth (10-15 for each material) below the cemento-enamel junction and restored. The root apices were sealed, the teeth coated with nail varnish except for 1 mm surrounding the restorations and the specimens were thermocycled (x500) in 2 per cent methylene blue solution. Root sections including the restorations were dissolved in acid and the concentrations of the dye determined spectrophotometrically. The sequence of the microleakage values were: Dyract < OptiBond < AeliteBond < All-Bond 2 < ScotchBond. It is concluded that Dyract had the lowest microleakage at dentine/cementum interface, which may increase the longevity of the restorative in the clinical situation, with no, or less secondary caries.     

桩道制备后根管冠方渗漏的体外实验

目的 本实验拟用染色实验，比较根管内牙胶余留全长、3、5、7mm两周后的冠方渗漏，为探讨桩道制备后根管充填的封闭性能做一参考：方法取86颗单根离体牙，按照牙胶余留量及暂时充填材料的不同分为8组，常规根管充填并桩道预备后，用次甲基蓝进行由冠方向根方的渗漏，2周后测量渗漏深度，统计结果并加以分析。结果各组均有渗漏，其中以牙胶封闭且根管内牙胶余留3mm组的渗漏距离最大．以氧化锌水门汀封闭且未去除根管内牙胶组的渗漏距离最小。但是8组的渗漏深度差异无统计学意义（P=0．1033）。结论桩道制备会增加根管充填的冠方渗漏，而氧化锌水门汀的封闭性能较牙胶强，但在两周时间内渗漏对根尖部封闭性能影响不大．     

An in vitro evaluation of four materials as barriers to coronal microleakage in root-filled teeth

AIM: To assess the ability of IRM, Coltosol, Vidrion R and Scotch Bond to seal the pulp chamber following root-canal treatment. METHODOLOGY: Root-canal treatment was completed on 100 extracted human mandibular molars. The teeth were divided into five groups of 20 teeth each, one group for each barrier material and one control group without barrier material. Two millimetres of the restorative material was placed on the pulp chamber floor. The teeth were thermocycled and evaluated for microleakage using India ink. Specimens were cleared and measurements made to the maximum point of dye penetration. The mean dye penetration for each group was compared by the Kruskal-Wallis test. RESULTS: All groups showed dye penetration. Coltosol and IRM sealed significantly better than the other groups, preventing the coronal leakage in 84% and 75% of the specimens, respectively. Scotch Bond exhibited the highest leakage (54% of specimens with dye penetration), which did not differ significantly from the positive control group (62% with dye penetration). CONCLUSIONS: None of the materials were able to prevent microleakage in all specimens. Vidrion R and Scotch Bond demonstrated the poorest results when used as barriers to coronal microleakage, whilst IRM and Coltosol were significantly better in preventing microleakage.