An in vitro study of apical and coronal microleakage of laterally condensed gutta percha with Ketac-Endo and AH-26

The purpose of this in vitro study was to compare both apical and coronal dye penetration when Ketac-Endo and AH-26 sealers were user with laterally condensed gutta percha. Crowns were removed from 28 teeth and the root canals were biomechanically prepared. The teeth were divided into two groups of 12 teeth. each and a control group of 4 teeth. Root canals in the two experimental groups were filled with laterally condensed gutta percha and either Ketac-Endo or AH-26 sealer. The ketac-Endo group had the coronal 3 mm of gutta percha and sealer removed and the resultant cavity was filled with Ketc-Endo alone. After the sealers had set, the root surfaces were coated with nail varnish except at the apex and at the coronal end. Positive control had no root fillings and were coated with nail varnish in the same manner while the negative controls were sealed apically and coronally with Cavit prior to apically and coronally with Cavit prior to sealing the entire external root surface with nail varnish. Specimens were placed in 2% methylene blue dye in a vacuum of 660 mm of mercury for five minutes and than left immersed for a further two days. The roots were vertically sectioned to determine the following mean levels of dye penetration: keta-Endo, 1.08 mm apically and 6.29 mm coronally; AH-26, 0.75 mm apically and 6.67 mm coronally. Positive controls had total leakage and negative controlls had no leakage. This study demonstrated that the apical and coronal seals obtained with Ketac-Endo and AH-26 were not significantly different although the apical seal obtained with each material was significantly better than the corresponding coronal seal.     

根管冠部预处理和不同锥度牙胶尖对根管充填后根尖部封闭性能的影响

目的:比较根管冠部预处理和不同锥度牙胶尖根管充填后的根尖封闭能力。方法:离体单根管恒牙42个,随机分为4组,用染料渗透法和透明标本法,测量根尖微渗漏距离,评价各组根尖封闭能力。结果:GG钻预处理和0.02锥度牙胶尖组根尖封闭能力最好;不用GG钻预处理和0.04锥度牙胶尖组根尖封闭能力最差。结论:根管预备时进行中上段的预处理,有利于增强根管充填后根尖段的封闭能力;用大锥度牙胶根管充填时应充分敞开根管中上段,否则易影响根尖段的充填效果,造成微渗漏;根管预备时进行冠方预处理,侧方加压法根充时选用合适的小锥度牙胶尖能取得较好的根管充填效果,提高根尖封闭能力。     

Influence of irrigants on the coronal microleakage of laterally condensed gutta-percha root fillings

AIM: To assess in vitro coronal microleakage in extracted human teeth after root-canal treatment, using different endodontic irrigants. METHODOLOGY: Fifty teeth with single root canals were prepared and filled using the lateral condensation of gutta-percha and Endométhasone sealer. Canal preparation consisted of initial shaping of the coronal two-thirds with Gates-Glidden burs size 2 and 3, followed by preparation of the apical stop and step-back flaring with manual files. Each group (n = 10) was irrigated with the following solutions: I--1% NaOCl, II--1% NaOCl + 17% EDTA, III--2% chlorhexidine gel, IV--2% chlorhexidine gel + 1% NaOCl, and V--distilled water. After root-canal filling, the teeth were incubated at 37 degrees C for 10 days followed by 10 days immersion in human saliva and an additional 10 days in India ink. The teeth were cleared and maximum dye penetration was determined digitally in millimetres. Statistical analysis was carried out using the Kruskal-Wallis test. RESULTS: Least leakage occurred with 1% NaOCl + 17% EDTA (2.62 mm) and 2% chlorhexidine gel (2.78 mm) (P > 0.05). NaOCl (3.51 mm), distilled water (6.10 mm) and 2% chlorhexidine gel + 1% NaOCl (9.36 mm) gave increased leakage with a significant difference compared to NaOCl + 17% EDTA and 2% chlorhexidine gel, and compared to one another (P < 0.05). CONCLUSIONS: Under the condition of this study, irrigation method during root-canal treatment influenced coronal microleakage. NaOCl + EDTA and chlorhexidine gel allowed better sealing following root filling.     

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.     

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.     

Assessment of apical and coronal root canal seals using contemporary endodontic obturation and restorative materials and techniques

AIM: The purpose of this study was to evaluate the sealing ability of two contemporary endodontic obturation and restorative techniques and materials. METHODOLOGY: Seventy-nine extracted human single-rooted teeth were distributed randomly in two experimental groups of 36 and 37 specimens (groups 1 and 2, respectively), one group of three positive controls and one of three negative controls. The teeth were radiographed preoperatively, accessed, and instrumented. After smear layer removal, the teeth in group 1 were obturated using the System B and Obtura and were restored coronally with Core Paste using Tenure as a bonding agent. The teeth in group 2 were obturated using the Microseal technique and were restored coronally with amalgam using Panavia 21 as a bonding agent. All teeth in groups 1 and 2 were coated with three layers of nail varnish on all of their surfaces apart from the apical 4.0 mm and the coronal area above the cemento-enamel junction. The positive control teeth were obturated, restored coronally and completely coated with varnish, whereas the negative control teeth were not obturated, restored coronally, nor coated with varnish. The teeth were radiographed postoperatively and retained in saline solution for 10 days. For the next 10 days they were submerged in India ink. Subsequently all teeth were demineralized, dehydrated and rendered transparent. Dye penetration was measured using a stereomicroscope. RESULTS: All materials and techniques provided minimal to zero dye penetration, apart from one specimen in the Core Paste group that showed 4.0 mm of dye penetration. The Wilcoxon rank sum test and t-test showed no statistically significant differences and all materials and techniques tested presented with a high degree of acceptability. CONCLUSIONS: It was concluded that these contemporary techniques and materials provide equally good results, but long-term studies are needed for outright inferences to be drawn relative to their clinical performance.     

An in vitro evaluation of the contents of root canals obturated with gutta percha and AH-26 sealer or Resilon and Epiphany sealer

The purpose of this study was to compare the contents of root canals obturated with gutta percha and AH-26 sealer (Dentsply, Tulsa, OK) to canals obturated with the Resilon and Epiphany (Pentron, Wallingford, CT) system. Canal contents were assessed by determining the percentage of canal space occupied by core material, sealer, voids, and debris. Forty extracted human maxillary anterior teeth were instrumented, and the teeth were randomly assigned to either the gutta percha/AH 26 group or the Epiphany/Resilon group. Canals were obturated, and the teeth were subsequently embedded in resin and sectioned horizontally at 2, 4, and 6 mm from the anatomic apex. Sections were photographed by using a low vacuum scanning electron microscope. Image-J (Wayne Rasband; National Institute of Health, Bethesda, MD) software was used to quantify the proportion of core material, sealer, voids, and debris in each canal. Percentages and statistical comparisons for each method were compared. There were no significant differences found among the two groups in terms of the percentage of core (p = 0.9), sealer (p = 0.58), debris (p = 0.999), or voids (p = 1.00). Additionally, there were no differences in the percentage of core material, sealer, debris, or voids at any of the examined levels (2, 4, or 6 mm).     

Sealing capacity in vitro of thermoplasticized gutta-percha with a solid core endodontic filling technique

Abstract— This study assessed the sealing capacity of two endodontic gutta-percha filling techniques. Thirty-four single-rooted fully developed teeth were endodontically accessed, instrumented and randomly divided into two experimental groups ( n =12) and two control groups ( n =5). In Group A, root canals were obturated using a solid core thermoplastic technique (Densfil), in Group B and Group C (negative control) canals were obturated with laterally condensed gutta-percha, and in Group D (positive control) canals were left un-obturated. AH-26 was used as the sealer. Two days later, the teeth were conventionally prepared for testing apical and coronal leakage, immersed in india ink for 5 days and subsequently cleared. The linear coronal and apical extent of dye penetration was measured under a light dissecting microscope. The mean apical leakage for Group A was 1.39 mm, and for Group B 2.76 mm, whereas the mean coronal leakage for Group A was 2.87 mm, and for Group B 4.03 mm. The differences between the groups were not statistically significant (P>0.05).     

An in vitro study of the coronal leakage of two root canal sealers using an obligate anaerobe microbial marker

The aim of this in vitro study was to investigate the coronal leakage of obligate anaerobes into root canals obturated with lateral condensation of cold guttapercha with two root canal sealers. Sixty extracted human teeth with straight, single root canals were prepared using the modified double-flared technique with balanced force under copious irrigation until the master apical file was size 40. The teeth were divided randomly into experimental groups (40 teeth) and control groups (20 teeth). In the experimental groups, 20 teeth were obturated with lateral condensation of cold gutta-percha and AH26 sealer and 20 teeth were obturated with the same technique using TubliSeal EWT sealer. In the control groups, 10 teeth were obturated with the same technique either with AH26 or TubliSeal EWT sealer. These teeth were completely sealed to serve as negative controls. The remaining 10 teeth were not obturated and served as positive controls. The root surface of each tooth was sealed with nail varnish except the apical 2 mm. The coronal part of each root canal was sealed with the cut end of polypropylene tube and placed in a glass bottle containing sterile Fastidious Anaerobe Broth (FAB). Aliquots of 0.5 mL of FAB were injected into the polypropylene tube and the model system was centrifuged at 168 g. An inoculum of Fusobacterium nucleatum in FAB was placed in each coronal chamber at 7-day intervals and daily observations were made for bacterial growth in the apical reservoir for 12 weeks. All positive control teeth showed bacterial leakage within a week, while the negative control teeth remained uncon-taminated throughout the test period. All the experimental teeth exhibited leakage of bacterial metabolites within 12 weeks, ranging from 1 to 12 weeks. The mean time for complete leakage in the AH26 and the TubliSeal EWT groups was 8.4 and 8.2 weeks respectively. There was no statistically significant difference (P > 0.05) in leakage between the AH26 and the TubliSeal EWT groups.     

根管治疗后冠部封闭材料的渗漏研究

目的:为临床上根管治疗后采用不同的冠部充填或暂时封闭材料的封闭性能提供理论依据。方法:对常规根管治疗后的80个离体牙分别采用磷酸锌黏固粉(锌封)、锌基 复合体、锌基 银汞合金3种材料充填后进行染料渗漏实验,比较冠渗漏情况。结果:所有的实验组都发生了不同程度的渗漏,经统计学分析,显示对照组和各实验组之间、锌封组与其它两实验组之间的冠渗漏均存在显著性差异;而锌基 复合体组、锌基 银汞合金组之间的差异无显著性。结论:对于根管治疗后不能及时进行冠修复的牙齿应采用永久充填的方法来进行暂时性的冠部封闭,以减少冠渗漏的发生,提高根管治疗的远期成功率;对于临床上冠部充填体损坏时间过长(超过1月)需重新做牙体修复的患牙,建议考虑重新根管治疗或髓腔消毒后再行牙体修复。     

In vitro evaluation of apical microleakage following canal filling with a coated carrier system compared with lateral and thermomechanical Gutta-Percha condensation techniques

Aim The apical sealing ability of a coated carrier system was evaluated in extracted human teeth and compared with lateral and thermomechanical condensation techniques using dye penetration. Methodology Sixty‐four extracted single‐rooted teeth were instrumented to an apical size 30 using 4% taper Hero 642? instruments (Micromega, Besançon, France). The sample was divided into three experimental groups. Twenty teeth were randomly obturated with lateral condensation, 20 with thermomechanical compaction and 20 teeth with the Herofill? Soft‐Core system. Four teeth were used as positive and negative controls. The teeth were covered with nail varnish up to 2 mm from the apical foramen and immersed in a 2% aqueous methylene blue dye solution for 1 week and then washed, dehydrated and embedded in resin. The apical 1 mm of each tooth was removed to reveal the apical limit of the preparation. Transverse sections of the teeth were taken at 500, 1000 and 1500 µm from this point and evaluated for apical leakage. Significant differences between the preparations were analysed with a semiautomatic analyser and the ratio of the dye‐penetrated surface to the total dentinal surface was calculated. Results Statistical analysis of the results demonstrated significantly less leakage for the Herofill? Soft‐Core system compared to lateral condensation in terms of total mean dentinal surface and at the 500 µm level. No other differences were noted between Herofill? Soft‐Core and thermomechanical or lateral condensation, either for the total mean value or at each level. Conclusions The Herofill? Soft‐Core system was a reliable obturation system in the apical portion and compared favourably with other gutta‐percha filling techniques.     

Apical microleakage evaluation of system B compared with cold lateral technique: In vitro study

The aim of this study was to evaluate in vitro the apical sealing ability of cold lateral and system B root filling techniques using dye penetration. Eighty-six extracted single-rooted human teeth were prepared and randomly divided into two experimental groups to be obturated by cold lateral condensation (n = 33) and system B (n = 33). The remaining 20 teeth served as positive and negative controls. The roots were embedded for 72 h in methylene blue dye solution and sectioned transversely for dye penetration evaluation using stereomicroscope. The results of this study showed that cold lateral condensation leaked significantly more (P < 0.001) than system B technique.     

五种髓腔暂封材料冠方微渗漏的体外评价

目的:评价CIMAVIT(碧兰)、Coltosol(康特)、CavitG(3M)、IRM(登士柏)和氧化锌丁香油酚粘固剂(ZOE,北京)等5种髓腔暂封材料的冠方微渗漏。方法:选取近期拔除的磨牙及前磨牙42个,排除龋齿、隐裂及牙合面过度磨耗牙。开髓并制作髓腔直线通路,洞缘1mm以外牙面封闭。随机分为5组,每组8个牙,分别用上述5种材料充填髓腔入口至充满。2个牙做对照,髓腔不充填。材料固化后,将试验牙浸入2%亚甲兰染料中,经过4℃和56℃各2min共40次温度循环及室温下16h浸泡,纵剖牙齿,观察染料沿洞壁与充填体间隙渗入的深度并分析各材料组间的差异。结果:5种材料的冠方渗漏有显著性差异(P<0.01)。CIMAVIT和Coltosol染料渗漏最少,IRM产生最多的微渗漏。结论:CIMAVIT和Coltosol可获得较理想的髓腔封闭效果。     

Bacterial leakage of GuttaFlow‐filled root canals compared with Resilon/Epiphany and Gutta‐percha/AH26‐filled root canals

The purpose of this study was to assess bacterial apical leakage in root canals obturated with GuttaFlow and compare this with the leakage of root canals obturated with Resilon/Epiphany or Gutta‐percha/AH26. A total of 55 single‐rooted human teeth were divided randomly into three experimental (n = 15) and two control groups (n = 5). Following a standardised preparation, the teeth were obturated with either GuttaFlow, Resilon/Epiphany or Gutta‐percha/AH26. A two‐chamber bacterial model using Enterococcus faecalis was employed to assess bacterial apical leakage for a period of 60 days. A Kruskal–Wallis test showed no significant differences between the seal of root canals obturated with GuttaFlow, Resilon/Ephiphany or Gutta‐percha/AH26.     

An assessment of microbial coronal leakage in teeth root filled with gutta-percha and three different sealers

The aim of this in vitro study was to determine the effect of three different root canal sealers on the bacterial penetration of obturated root canals. Eighty extracted human teeth with straight, single root canals were prepared using the modified double-flared technique with balanced force under copious irrigation until the master apical file was size 40. The teeth were divided randomly into experimental groups (60 teeth) and control groups (20 teeth). Twenty experimental teeth each were obturated by lateral condensation of cold gutta-percha with AH26, Apexit or Tubliseal EWT sealer. In the control groups, 10 teeth were obturated using the same technique with AH26, Apexit or Tubliseal EWT sealer. These teeth were completely sealed to serve as negative controls. The remaining 10 teeth were not obturated and served as positive controls. The root surface of each tooth, except the apical 2 mm, was sealed with nail varnish. The coronal part of each root canal was sealed with the cut end of a polypropylene tube and placed in a glass bottle containing sterile Todd-Hewitt Broth (THB). Aliquots of 0.5 ml of THB were injected into the polypropylene tube and the model system was centrifuged at 168 g. An innoculum of Streptococcus sanguis in THB was added to the tube at 5-day intervals and daily observations were made for bacterial growth in the apical reservoir for 90 days. All positive control teeth showed bacterial penetration within 24 h and negative control teeth remained uncontaminated throughout the test period. Leakage through the experimental teeth varied from 7 to 86 days. There was no statistically significant difference (P > 0.05) in leakage of the obturated canals between AH26, Apexit and Tubliseal EWT sealers.     

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.     

An apical leakage study in the presence and absence of the smear layer

The apical seal produced by low-temperature injection of gutta-percha, with or without root canal sealer, in the presence or absence of the smear layer was evaluated quantitatively using an electrochemical technique. The root canals of 44 teeth were prepared with the smear layer intact following a final flush of NaOCl (group 1), while the root canals of a further 44 teeth were prepared and the smear layer removed with a final flush with EDTA followed by NaOCl (group 2). Subgroups were obturated using Ultrafil System alone or accompanied by Calciobiotic Root Canal Sealer. Microleakage data was expressed as a percentage of apical leakage evident in each group. Statistical analysis of the results revealed that the groups obturated with Ultrafil alone showed no significant differences in leakage compared with the groups where sealer was used, either when the smear layer had been left intact or removed. (P>0.05). However, comparison of the combined two groups with smear layer present versus the combined two groups with smear layer removed showed a highly significant difference (P<0.01), with the incidence of leakage reduced in the absence of the smear layer.     

Efficiency of diode laser and ultrasonic-activated irrigation in retreatment of gutta percha and bioceramic sealer: An in vitro study

This study was to determine the effectiveness of diode laser (LI) and ultrasonic (UI)-activated irrigation with or without a surfactant as adjunct techniques during the retreatment of gutta-percha and tricalcium silicate-based sealer (BC) sealer. Forty-two single-rooted premolars were instrumented and filled with gutta-percha and BC sealer, then retreated using NiTi retreatment rotary files. Teeth were randomly divided into three equal groups: Control (manual irrigation), UI and LI groups. Each group was subdivided into 2.5% NaOCl irrigant and ChlorCid™️ Surf subgroups. The amount of material removed following UI and LI was significantly greater than that of manual irrigation (p < 0.0001). However, there was no significant difference between the surfactant subgroups, irrespective of irrigation technique (p = 1.00, p = 0.535, p = 0.805). The use of UI and LI adjuncts to NiTi rotary retreatment techniques showed significant improvement in gutta-percha with BC sealer removal. However, surfactants had no effect on the efficacy.     

3种根充糊剂根尖封闭性能的实验研究

目的评价3种根充糊剂的根尖封闭能力。方法30颗离体单根管前牙随机分为国产根充糊剂、Vitapex糊剂和AHPlus糊剂3组,每组10颗,分别用加牙胶尖以冷侧压法充填根管,用染料渗透法和透明标本法在立体显微镜下测量根尖微渗漏。结果3组根尖微渗漏的均值分别为:国产根充糊剂组(2.555±1.129)mm,Vitapex糊剂组(1.212±0.625)mm,AH Plus糊剂组(0.919±0.427)mm,3组间差异有显著性(P<0.01),Vitapex组和AH Plus组的微渗漏无明显差异(P>0.05)。结论Vi-tapex糊剂和AH Plus糊剂的根尖封闭性能均优于国产根充糊剂。