Spreader penetration during lateral compaction of resilon and gutta-percha

Resilon, a thermoplastic, polyester polymer-based filling material, is a new material used for sealing root canals after chemomechanical preparation. The purpose of this in vitro study was to compare nickel-titanium (NiTi) spreader penetration in root canals having a .04 taper preparation using .02 and .04 tapered master gutta-percha cones and .02 and .04 tapered master Resilon cones. Twenty canals, from extracted human teeth, were cleaned and shaped to a standardized 40/.04 size. Master cones of .02 or .04 tapered gutta-percha and .02 or .04 tapered Resilon were placed in each canal. A fine-fine NiTi spreader was then placed next to the master cone with a 1.5-kg force. The penetration depth was measured, subtracted from working length, and recorded. A significant difference in penetration depth (p < 0.01) was found for both taper of the cone and material used. The depth of spreader penetration from greatest to least was .02 tapered Resilon, .02 tapered gutta-percha, .04 tapered Resilon, and .04 tapered gutta-percha.     

Intraorifice sealing of gutta-percha obturated root canals to prevent coronal microleakage

A study was conducted to evaluate Cavit, Intermediate Restorative Material, and Super-EBA as intraorifice filling materials to prevent coronal microleakage. Root canal instrumentation and obturation was done on 74 extracted single-rooted teeth. Three and one-half millimeters of the gutta-percha was removed from the coronal aspect of the root canal and replaced with one of the three filling materials. The teeth were suspended in scintillation vials containing trypticase soy broth, and human saliva was added to the pulp chambers. Microbial penetration was detected as an increase in turbidity of the broth corresponding to bacterial growth. At the end of 90 days, the results showed that 15% of the Cavit-filled orifices leaked, whereas 35% of the Intermediate Restorative Material and Super-EBA-filled orifices leaked. The gutta-percha obturated root canals that received an intraorifice filling material leaked significantly less than the obturated, unsealed control group--all of which leaked in < 49 days.     

An evaluation of .06 tapered gutta-percha cones for filling of .06 taper prepared curved root canals

AIM: To compare the area occupied by gutta-percha, sealer, or void in standardized .06 tapered prepared simulated curved canals and in mesio-buccal canals of extracted maxillary first molars filled with a single .06 gutta-percha point and sealer or lateral condensation of multiple .02 gutta-percha points and sealer. METHODOLOGY: Simulated canals in resin blocks with either a 30 degrees curve and radius of 10.5 mm (n = 20) or a 58 degrees curve and 4.7 mm radius (n = 20) and curved mesio-buccal canals of extracted maxillary first molars (n = 20) were prepared using .06 ProFiles in a variable tip crown-down sequence to an apical size 35 at 0.5 mm from the canal terminus or apical foramen. Ten 30 degrees and 58 degrees curved resin canals and 10 canals in the extracted teeth group were obturated with .02 taper gutta-percha cones and AH 26 sealer using lateral condensation. The time required to obturate was recorded. The remaining canals were obturated with a single .06 taper gutta-percha cone and AH 26 sealer. Excess gutta-percha was removed from the specimens using heat and the warm mass vertically condensed. Horizontal sections were cut at 0.5, 1.5, 2.5, 4.5, 7.5 and 11.5 mm from the canal terminus or apical foramen. Colour photographs were taken using an Olympus 35 mm camera attached to a stereomicroscope set at x40 magnification, and then digitized using a flatbed scanner. The cross-sectional area of the canal contents was analysed using Adobe PhotoShop. The percentage of gutta-percha, sealer or voids to the total root canal area were derived and data analysed using unpaired Student's t-test and the Mann-Whitney U-test. RESULTS: In the 30 degrees curved canals the levels had between 94 and 100% of the area filled with gutta-percha with no significant difference (P > 0.05) between the lateral condensation and single cone techniques. In the 58 degrees curved canals the levels had 92-99% of the area filled with gutta-percha, with the single cone technique having significantly (P < 0.05) more gutta-percha fill at the 2.5 mm level only. In the mesio-buccal canals of the teeth the levels had between 72 and 96% of the area filled with gutta-percha with no significant difference (P > 0.05) between the lateral condensation and single cone technique. The time for obturation was significantly (P < 0.05) greater for lateral condensation compared with the single cone technique in all groups. CONCLUSIONS: The .06 taper single cone technique was comparable with lateral condensation in the amount of gutta-percha occupying a prepared .06 tapered canal. The .06 single cone technique was faster than lateral condensation.     

An in-vitro study of smear layer removal and microbial leakage along root-canal fillings

The objective of this study was to determine the effect of removal of the smear layer on canal obturation as measured by penetration of bacteria from a coronal direction. Fifty-four extracted human teeth were decoronated and instrumented in a uniform manner. Following instrumentation the root canals of 20 teeth were rinsed with 17% EDTA and 5.25% NaOCl to remove the smear layer before obturation. A second group of 20 teeth were flushed with NaOCl alone. The teeth of both groups were obturated with Thermafil^TM plastic carriers and Roth's sealer. The root canals of another 10 teeth, five rinsed with EDTA and five without, were obturated with Thermafil^TM without sealer. Two teeth serving as positive controls were instrumented but not obturated, while another set of two were sealed coronally and apically to serve as negative controls. The root surface of each tooth was sealed with nail varnish. A small chamber was thoroughly sealed around the coronal aspect of each tooth so that bacteria placed therein could move only through the obturated canal space. Each tooth was placed in a test tube containing sterile trypticase soy broth (TSB). An inoculum of Proteus vulgaris in TSB was placed in each coronal chamber at five day intervals and daily observations were made for bacterial growth in the apical reservoir for 21 days. Both positive control teeth showed bacterial penetration after 24 h. Neither of the two negative control teeth demonstrated penetration for the duration of the study. The frequency of bacterial penetration through teeth obturated with intact smear layer (70%) was significantly greater than that of teeth from which the smear layer had been removed (30%) P< 0.05. All but one tooth obturated without sealer exhibited bacterial penetration, irrespective of the presence or absence of smear layer. Removal of the smear layer enhanced sealability as evidenced by increased resistance to bacterial penetration.     

不同锥度牙胶尖热垂直加压法根管充填的临床疗效分析

目的研究采用不同锥度牙胶尖热垂直加压法行根管充填的临床X线片评价及术后1年的临床疗效。方法选择上颌前牙单、直根管患牙40颗为研究对象,采用Hero 642机用镍钛锉预备至0.06锥度30号锉,随机分为2组,每组20颗患牙。分别使用0.02锥度和0.06锥度牙胶尖采用热垂直加压法充填根管。对术后即刻X线片进行2组患牙根管充填质量、侧支根管充填及超填情况的比较;并比较2组患牙术后1年的临床疗效。结果0.02锥度组与0.06锥度组根管充填质量、侧支根管充填及超填情况没有明显差异。术后1年复查,0.02锥度组与0.06锥度组的治疗成功率一致,但0.06锥度组病变愈合趋势快于0.02锥度组。结论对于镍钛旋转器械预备的较大锥度单、直根管,采用热牙胶垂直加压法行根管充填,使用与根管预备锥度相一致的大锥度牙胶尖能够提高根管治疗的临床疗效。     

Evaluation of pigmented intraorifice barriers in endodontically treated teeth

The purpose of this study was to evaluate the effectiveness of three pigmented glass ionomer cements used as intraorifice barriers to prevent coronal microleakage. One hundred ten extracted mandibular human premolars were divided into four experimental groups of 25 teeth each and two control groups of 5 teeth each. The experimental teeth were instrumented and obturated using thermoplasticized gutta-percha and AH26 sealer. Group 1 teeth received no further treatment. Teeth in groups 2 through 4 had 1 of 3 pigmented glass ionomers (Vitrebond, GC America, and Ketac-Bond) placed as an intraorifice barrier. Positive control teeth were instrumented but not obturated. The negative control teeth were instrumented, obturated, and externally sealed with epoxy resin. The coronal 3 mm of each root was sealed into the lumen of an 18-mm segment of latex surgical tubing. After the apparatus was sterilized, 2.0 ml of a 24 h growth of Proteus vulgaris in trypticase soy broth (TSB) was placed in the coronal reservoir of the tooth. The inoculated apparatus was placed into a presterilized test tube containing 1.5 ml of TSB and incubated for 90 days at 37 degrees C. The TSB in the lower reservoir was observed daily for turbidity, which would indicate leakage along the full length of the obturated root canal. To determine if differences in microbial leakage occurred among the four experimental groups, Pearson's chi 2 and Fisher's exact tests were performed. The confidence level was set at 95%. The positive and negative controls validated the microbial testing method. The teeth without an intraorifice barrier leaked significantly more than teeth with Vitrebond intraorifice barriers (p < 0.05). The difference in leakage among the experimental glass ionomer barriers was not significant (p > 0.05).     

Does cold burnishing gutta-percha create a better apical seal?

This study investigated the seal created by cold burnishing the gutta-percha exposed after apical root resection of endodontically treated teeth. Sixty single-rooted extracted human teeth with a single straight canal were divided into four experimental groups of 15 teeth each. In two of the experimental groups the canals were instrumented and obturated well with laterally condensed gutta-percha and sealer. The remaining two groups were instrumented and poorly obturated with laterally condensed gutta-percha and sealer. The apical 2 mm of all the teeth were then resected and the effect of cold burnishing the exposed gutta-percha was investigated using a linear dye penetration technique. Under the condition of this study, cold burnishing gutta-percha after apical root resection of a well-obturated root canal resulted in a poorer apical seal than if no burnishing were performed. Cold burnishing the exposed gutta-percha after apical root resection of poorly obturated root canals improved the apical seal as compared with nonburnished poorly obturated canals.     

Comparison of lateral condensation and thermomechanically compacted warm alpha-phase gutta-percha with a single cone for obturating curved root canals

OBJECTIVE: To evaluate and compare the sealability and radiographic quality of root fillings in extracted teeth by using lateral condensation of gutta-percha or alpha-phase gutta-percha in conjunction with a single gutta-percha cone. STUDY DESIGN: A total of 108 single-rooted teeth were divided into 2 groups of 54 teeth based on canal shape. Canals were prepared to a minimum 0.055 taper and enlarged to a size 35 at the working distance. Irrigation was done with 17% EDTA and 2.5% sodium hypochlorite (NaOCl) to remove smear layer. One group was obturated by using cold lateral condensation of gutta-percha; the other group was obturated with thermomechanically compacted alpha-phase gutta-percha and a single cone of gutta-percha. Apical extrusion of sealer or gutta-percha was recorded. Sealability of each technique was assessed by dye penetration. The radiographic quality of obturation was also determined. RESULTS: Root canals filled with alpha-phase gutta-percha and a single cone had significantly more extrusion of sealer than canals filled by lateral condensation. Lateral condensation achieved significantly better scores for radiographic quality. There was no significant difference between the 2 filling techniques in terms of apical or coronal leakage. CONCLUSIONS: Thermomechanically condensed alpha-phase gutta-percha used in conjunction with a single gutta-percha cone had poorer radiographic quality than laterally condensed gutta-percha.     

Effect of gravity and capillarity on human saliva penetration in coronally unsealed obturated root canals

AimThe purpose of this study was to evaluate the effect of gravity and capillarity on penetration of human salivary bacteria into the entire length of obturated root canals, and to demonstrate the dye penetration configuration.Materials and methodsFifty single-rooted premolars were decoronated, prepared to a standardized length of 15 mm, instrumented, and randomly divided into two groups (A and B) of 25 teeth each. Each group consisted of experimental (15 samples) and negative and positive controls (five samples each). The experimental groups were obturated with gutta-percha and root canal sealer. The positive control groups were obturated with a single cone of gutta-percha and root canal sealer. The outer surfaces (except for the apical 2 mm) were covered with two layers of nail varnish. An apparatus containing Brain Heart Infusion broth was designed, in which the teeth were placed. The samples in Group A were placed upside down, while Group B was placed normally. The coronal portions of the samples were placed in contact with fresh saliva. The number of days required for bacteria to penetrate the entire length of canals was determined. The samples were then immersed in India ink to determine the dye penetration configuration. Data were analyzed using Student’s t-test.ResultsThe extent of dye penetration was significantly greater in Group B compared to Group A, and they were in a pattern rather than linear form.ConclusionsGravity and capillarity insignificantly affected bacterial leakage. Although gravity and capillarity did not affect bacterial penetration when applied to the coronal access of endodontically treated teeth, it seems that they can promote penetration of India ink into the canal after the bacterial test on the same tooth.     

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).     

不同锥度的主牙胶尖对弯曲根管根尖封闭能力的对比研究

目的比较0.02、0.04和0.06锥度的主牙胶尖对弯曲根管的根尖封闭能力。方法离体弯曲单根管恒牙根43个,机用ProTaper镍钛锉以冠下法根管预备后,随机分成A、B、C三个实验组（每组11个牙根）和D、E两个对照组（每组5个牙根）,A、B、C组分别采用25/0.02、25/0.04、25/0.06主牙胶尖加AH-plus糊剂行侧方加压充填。D组为阴性对照组,AH-plus根管糊剂充填。E组为阳性对照组,25/0.06牙胶尖垂直加压充填。用葡萄糖氧化酶比色测定法,于第7天检测从冠方向根方漏出的葡萄糖量,评价各组根尖封闭能力。结果 D组与A、B、C、E组的差异均有统计学意义（P〈0.05）,而其余组两两间差异无统计学意义（P〉0.05）。结论短期内本实验所用的三种锥度的主牙胶尖对弯曲根管均有良好根尖封闭能力。     

In vitro evaluation of three techniques to obturate 0.06 taper canal preparations

The aim of this study was to evaluate the ability of three obturation methods to seal root canals prepared using 0.06 taper rotary instruments. Forty-five extracted human single-rooted teeth were instrumented with 0.06 taper Profile nickel-titanium rotary files and randomly divided into three experimental groups containing 15 teeth each. The first group was obturated using the System B technique with 0.06 taper standardised gutta-percha points, the second group was obturated using the System B technique with non-standardised MF gutta-percha points, the third group was obturated by cold lateral condensation technique using standardised 0.02 taper master gutta-percha points. Apical leakage of the roots was evaluated by dye penetration using a stereomicroscope after sectioning the roots. The group obturated using System B and 0.06 taper gutta-percha points showed the least dye penetration. However, the difference in the linear extent of dye penetration was not statistically significant.     

The effect of standard or serial preparation on single cone obturations

Summary. This leakage study, in vitro , used methylene blue dye as a marker to detect the extent of apical fluid penetration after buccal roots from maxillary first bicuspids were instrumented either by the standard technique or serially, and obturated with laterally condensed gutta-percha and sealer, a single gutta-percha master cone and sealer, or sealer alone. The linear extent of dye penetration was measured after the roots were split longitudinally. In this study the laterally condensed gutta-percha and sealer technique resulted in the least apical penetration of dye. The single gutta-percha cone and sealer technique groups had less dye penetration than the groups where obturation was with sealer alone. The use of the standard or serial technique of preparing canals resulted in no significant difference in the quality of obturation using a single gutta-percha cone with sealer or using sealer alone.     

Lateral condensation in canals prepared with nickel titanium rotary instruments: an evaluation of the use of three different master cones

Forty-five single-rooted teeth were instrumented with ProFile ISO .06 nickel-titanium rotary instruments and obturated with lateral condensation using three different master cones: an ISO-standardized gutta-percha cone (group A), a Dia-ISO(GT).06 gutta-percha cone (group B), and a size medium gutta-percha cone (group C). Obturation efficiency in each group was evaluated by recording the number of accessory cones utilized. To evaluate obturation quality in the three groups, a cross-sectional observation of the ability of the gutta-percha in each group to obliterate the prepared canal space was carried out. Results showed that obturation efficiency was significantly greater in groups B and C than in group A. There was no significant difference in obturation quality between any of the three groups.     

Comparison of spreader penetration during lateral compaction of .04 and .02 tapered gutta-percha

The purpose of this study was to compare the initial penetration depth of fine-fine nickel-titanium (NiTi) and fine-fine stainless-steel (SS) spreaders during lateral compaction of .02 or .04 tapered master gutta-percha cones and to evaluate the effect of increasing canal curvature on penetration depth. Fifty-one root canals were instrumented to a standardized size and grouped by degree of curvature for comparison. Our results showed that NiTi spreaders penetrated to a significantly greater depth than SS spreaders using .02 tapered gutta-percha in canal curvatures greater than 20 degrees and when using .04 tapered gutta-percha regardless of canal curvature. 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). Both NiTi and SS spreaders penetrated to a greater depth as canal curvatures increased to greater than 20 degrees (p < 0.05). Both NiTi and SS spreaders penetrated to a shallower depth with .04 tapered gutta-percha compared with .02 tapered gutta-percha (p < 0.0001).     

不同锥度牙胶尖热垂直加压法根尖封闭性的研究

目的对不同锥度牙胶尖热垂直加压法根管充填的根尖封闭性进行比较。方法将62颗下颌切牙经GG钻及Hero642锉根管预备至0.06锥度30号,然后随机分为0.02锥度组（ 30颗）、0.06锥度组（ 30颗）和阳性对照组（ 2颗）,0.02锥度组和0.06锥度组分别应用0.02锥度牙胶尖和0.06锥度牙胶尖加Cortisomol糊剂热垂直加压法进行根管充填,阳性对照组不进行根管充填。将0.02锥度组和0.06锥度组中的10颗牙置入印度墨水中浸泡24 h,10颗牙置入印度墨水中浸泡10 d,10颗牙置入Hank′s平衡盐溶液67 d后再置入印度墨水中浸泡90 h。阳性对照牙置入印度墨水中浸泡24 h。应用立体显微镜三维测量根尖渗漏的线性长度,对根尖封闭性进行评价。结果阳性对照牙根管全长均有墨水染色。0.02锥度组随浸泡时间延长其根尖渗漏明显增加,0.06锥度组随浸泡时间延长根尖渗漏无明显增加。在浸泡24 h和10 d时,0.02锥度组和0.06锥度组的根尖渗漏距离无显著性差异（ P=0.601,P=0.471）;浸泡67 d时,0.02锥度组和0.06锥度组的根尖渗漏距离有显著性差异（ P=0.041）。结论使用与根管锥度相一致的牙胶尖进行根管充填,能够得到更好的根尖封闭性。     

A comparison of spreader penetration depth and load required during lateral condensation in teeth prepared using various root canal preparation techniques

AIM: To compare the influence of various root canal preparation techniques on spreader penetration depth and load required during lateral condensation with gutta-percha and sealer. METHODOLOGY: Eighty extracted human teeth with single and straight canals were used. Twenty teeth were instrumented using one of four root canal preparation techniques. The four preparation techniques were: step-back technique without Gates-Glidden drills, step-back technique with Gates-Glidden drills, crown-down pressureless technique and hybrid technique (step-down/step-back). After root canal preparation had been completed a simulated periodontal ligament was fabricated from a uniform layer of silicone impression material. The roots were then mounted in an acrylic resin to simulate the physical condition found in tooth socket. A standardized stainless steel hand spreader of the same size as the master apical file was mounted in an Instron testing machine and lateral compaction with gutta-percha and sealer was performed. The load value was recorded from the Instron testing machine. The spreader penetration depths were measured with an endodontic ruler. The data obtained were analysed statistically using anova and Student's t-tests. RESULTS: No significant difference in initial spreader load needed to condense the master cone was found amongst the four canal preparation techniques (P > 0.05). The step-back technique with Gates-Glidden drills and the hybrid technique demonstrated the least difference between the initial spreader penetration and the working length (mean 1.925 and 2.25 mm, respectively). The step-back technique without Gates-Glidden drills and the crown-down pressureless technique had the greatest difference between initial spreader penetration and the working length (mean 4.425 and 4.75 mm, respectively). CONCLUSION: The flare created by canal preparation affected spreader penetration depth, but had no effect on the spreader load.     

Active versus passive microleakage of Resilon/Epiphany and gutta-percha/AH Plus

The purpose of this in vitro study was to assess the active versus passive dye microleakage and apical sealing ability of laterally condensed gutta-percha/AH Plus versus Resilon/Epiphany. One hundred and twenty teeth were instrumented and divided into experimental, positive and negative control groups. In group 1, the teeth were obturated with gutta-percha/AH Plus and in group 2 the teeth were obturated with Resilon/Epiphany. The apical seal was evaluated with a passive and active dye penetration test. Absorbance of the extracted dye was determined with a spectrophotometer. Resilon/Epiphany showed less dye penetration in comparison with the gutta-percha/AH Plus group (P < 0.05). There were no statistically significant differences between the passive and active dye penetration tests (P > 0.05). In this in vitro study, canals obturated with Resilon/Epiphany showed less apical leakage than those obturated with gutta-percha/AH Plus, regardless of the type of dye penetration test used.     

Evaluation of the apical seal in root canals prepared with a new rotary system and obturated with a methacrylate based endodontic sealer: an in vitro study

The purpose of this study was to evaluate in vitro the apical seal of root canals prepared with a new rotary system, Anatomic Endodontic Technology (AET) and filled with a methacrylate based endodontic sealer and a single gutta-percha cone and a lateral condensation technique, using the methacrylate based endodontic sealer/filler or Grossman's cement. The root canals of 45 freshly extracted human maxillary anterior teeth were prepared and then randomly assigned to three groups of 15 teeth each. After cleaning and shaping the teeth were obturated as follows: in group 1 the canals were filled with a methacrylate based sealer and a single gutta-percha cone; in group 2 the canals were filled using a lateral condensation technique with gutta-percha and the methacrylate based sealer; and in group 3, the canals were filled by means of lateral condensation of gutta-percha and Grossman's cement (control group). The specimens were stored in 100% relative humidity at 37 degrees C for 72 h, after which the coronal portion and the root surface of each tooth was covered with three layers of nail varnish and a final layer of sticky wax. After immersion in 2% methylene blue dye for 7 days, the specimens were imbedded in clear orthodontic resin and sectioned. Dye penetration was evaluated by an independent investigator using a stereo microscope. The results demonstrated that more pronounced leakage occurred in root canals obturated with the lateral condensation technique and Grossman's cement (p < 0.05). The least amount of dye leakage was observed for group 1 and 2 in which the methacrylate based sealer was used, either with a single gutta-percha cone or with lateral condensation of gutta-percha.     

Apical sealing efficacy of endodontic obturation techniques

Summary. This study in vitro utilized methylene blue dye to evaluate root canal apical leakage after maxillary central incisors were serially instrumented and obturated with laterally condensed guta-percha and sealer, a single fitted gutta-percha master cone and sealer, sealer alone or paste alone. The linear extent of dye penetration was measured, and the volume of dye leakage was evaluated using a dye-recovery spectrophotometric technique. Under the conditions of this study, the teeth obturated with laterally condensed gutta-percha and sealer exhibited the least leakage. The single gutta-percha cone and sealer technique had no advantage over use of sealer or paste when used alone.