Removal of intracanal smear layer by doxycycline: SEM analysis

The aim of this study was to verify the efficacy of doxycycline used alone or in association with sodium hypochlorite on smear layer removal. The canals of extracted human teeth were instrumented using a stepback technique. At the end of preparation, they were irrigated with doxycycline (Group 1), ethylenediaminetetraacetic acid + sodium hypochlorite (Group 2), doxycycline + sodium hypochlorite (Group 3) and water (Group 4). The dentinal wall of the cervical, middle and apical thirds was graded according to the amount of remaining debris and smear layer. The results were analysed using the Kruskal–Wallis test (P < 0.05). In Groups 2 and 4, the dentine was completely free and covered with smear layer, respectively. The results from the cervical and middle thirds of Group 3 were worse than those in Groups 1 and 2 (P < 0.05). In relation to apical third, there were differences (P < 0.05) between all groups with best results for Group 2. Doxycycline was effective in removing smear layer from cervical and middle thirds. The use of doxycycline + sodium hypochlorite was partially effective in the cervical and middle thirds, but ineffective in the apical third.     

利用扫描电子显微镜分析声波辅助根管荡洗作用时间对玷污层清理效果的影响

目的 通过扫描电子显微镜(SEM)观察不同作用时间下根管壁玷污层的清除情况,以明确临床中使用声波辅助设备荡洗根管的最佳时间。方法 选择单直根管的人离体前牙56颗,常规机械预备后根据冲洗剂不同分为2个实验组：生理盐水组和EDTA组,每组均辅助使用声波驱动的VDW荡洗工作尖完成根管荡洗。生理盐水组根据荡洗时间分为3个亚组：5 s组,30 s组,50 s组;EDTA组根据荡洗时间分为6个亚组：5 s组,10 s组,20 s组,30 s组,40 s组,50 s组。对照组不进行根管冲洗及荡洗。SEM观察根管壁冠、中、根三段的玷污层情况。结果 生理盐水组荡洗30 s后冠方1/3与对照组及5 s组相比差异有统计学意义(P<0.05),根中下段无差异(P>0.05);50 s后根尖区玷污层评分与其余各组评分相比差异有统计学意义(P<0.05)。EDTA组荡洗5或10 s后,根管中上段玷污层评分与对照组相比差异有统计学意义(P<0.05),根尖区无意义(P>0.05);20 s～40 s组根尖区与前两组相比差异有统计学意义(P<0.05);50 s组根尖区与其余各组相...     

The effect of different irrigation protocols on smear layer removal in root canals of primary teeth: a SEM study

Objective: The purpose of this study was to compare the efficacy of different irrigation protocols on smear layer removal in root canals of primary teeth by scanning electron microscopy (SEM).

Material and methods: The study was conducted with 40 extracted maxillary primary incisor teeth divided into four groups (n?=?10) as 1% sodium hypochlorite (NaOCl), 10% ethylenediaminetetraacetic acid (EDTA)+1% NaOCl, 6% citric acid (CA)+1% NaOCl, and 0.9% physiological saline (PS). After the irrigation procedures, root canal walls were examined by SEM and the efficacies of irrigation solutions in smear layer removal were scored and compared. Data were analyzed using Kruskal–Wallis, Friedman and Siegel Castellan tests.

Results: The smear layer removal was found to be statistically more effective in groups of 10% EDTA + 1% NaOCl and 6% CA + 1% NaOCl when compared with the other groups (p?<?.05). Smear removal efficacy was statistically significantly higher in coronal and medium thirds when compared with the apical regions in the experimental groups.

Conclusions: It was concluded that 10% EDTA + 1% NaOCl and 6% CA + 1% NaOCl could be alternative irrigation protocols regarding smear layer removal. However, due to the absence of erosive dentinal changes, it might be suggested that using 6% CA + 1% NaOCl can be recommended compared to 10% EDTA + 1% NaOCl in primary root canals.     

Evaluation of ethylenediaminetetraacetic acid (EDTA) solution and gel for smear layer removal

The purpose of this in vitro study was to compare the efficacy of 24% ethylenediaminetetraacetic acid (EDTA) gel and 17% EDTA solution in cleaning dentine walls after root canal instrumentation. Thirty human canine teeth were divided into three groups of 10 teeth each. In Group 1, 1% sodium hypochlorite was used as the irrigating solution; in Group 2, 1% sodium hypochlorite was used with 17% EDTA solution; and in Group 3, 1% sodium hypochlorite was used with 24% EDTA gel. The presence of a smear layer was analysed after instrumentation using scanning electron microscopy. The Kruskal-Wallis test revealed a statistical difference (P < 0.05) between Groups 1 and 2, and also between Groups 1 and 3. No difference was observed between Groups 2 and 3 (P > 0.05). The results indicate that 1% sodium hypochlorite alone does not remove the smear layer and that there was no statistical difference between EDTA gel and EDTA solution in smear layer removal.     

Effectiveness of 1 mol L-1 citric acid and 15% EDTA irrigation on smear layer removal

AIM: The aim of this study was to evaluate in vitro the cleansing and smear layer removal capability of alternate canal irrigation with citric acid and NaOCl. METHODOLOGY: Eighty-one teeth were divided into three groups on the basis of the type of instrumentation, namely, manual stainless steel, Ni-Ti mechanized ProFile .04 taper or MACXim. The groups were further divided on the basis of irrigation protocol: 5% NaOCl alone, NaOCl alternated with 1 mol L-1 citric acid solution or a combination of 15% EDTA and Cetrimide solution. After longitudinal sectioning, dentinal walls were microphotographed with scanning electron microscopy at x300 and x1000 magnifications. Qualitative and quantitative cleansing level evaluations were performed using computerized image analysis software. Data were statistically evaluated using Kruskal-Wallis analysis and t-test. RESULTS: Qualitative evaluation at x300 and x1000 showed no statistically significant differences in cleansing ability between citric acid, EDTA and NaOCl groups. Quantitative evaluation of smear layer removal, measured as open tubules/total dentinal surface ratio, showed that 1 mol L-1 citric acid solution was comparable to EDTA (11.97% vs. 10.36%) (NS); in samples treated with ProFile .04 taper instruments citric acid was most effective (16.17%), whilst in the group treated with manual instrumentation EDTA and Cetrimide were the most effective (11.94%). Specimens irrigated with 5% NaOCl demonstrated significantly more cleansing than those obtained in the other two groups (P < 0.001). CONCLUSIONS: 1 mol L-1 citric acid solution was as effective in removing smear layer as EDTA, but was superior in specimens treated with ProFile .04 taper instruments.     

The use of ultrasound for the removal of the smear layer. The effect of sodium hypochlorite concentration; SEM study

This study was carried out to determine the optimum concentration of sodium hypochlorite activated by ultrasound needed to remove the smear layer from an instrumented root canal wall. The results indicated that under the conditions of this experiment a 4 per cent solution of sodium hypochlorite removed all of the smear layer from all 5 specimens; a 2 per cent solution was almost as effective; 1 per cent or 1/2 per cent solutions were less effective, and water was the least effective. A 2 per cent solution of sodium hypochlorite activated by ultrasound would appear to be the optimum concentration for the production of a smear free root canal wall under clinical conditions.     

次氯酸钠配合SmearClear清除根管玷污层的研究

目的:比较4种根管冲洗方法清除根管玷污层的效果,研究出有效去除根管玷污层的方法。方法:20个无龋单根前牙随机分为4组,A组:60℃30 g/L次氯酸钠液加170 g/L EDTA,#15K锉提拉冲洗;B组:60℃30 g/L次氯酸钠液加SmearClear,#15K锉提拉冲洗;C组:60℃30 g/L次氯酸钠液加170 g/LEDTA液超声荡洗;D组:60℃30 g/L次氯酸钠液加SmearClear超声荡洗。扫描电镜下放大2 500倍和4 000倍观察根尖1/3、根中1/3和根上1/3玷污层清除情况。按照根管壁玷污层清除情况和根管壁腐蚀程度的分级标准进行统计学分析。结果:①根管壁玷污层清除情况:4组在根上2/3区玷污层均有效去除,各组间差异无统计学意义(P>0.05),B组根尖1/3基本无玷污层,A、C、D组仅见少部分玷污层被去除,B组与A、C、D组差异有统计学意义(P<0.05);②根管壁腐蚀性比较:C、D组根上2/3区腐蚀度较大,而A、B组未见明显腐蚀。C、D组与A、B组相比差异有统计学意义(P<0.05),各组根尖1/3根管壁腐蚀度差异无统计学意义(P>0.05)。结论:SmearClear与60℃30 g/L次氯酸钠液联合应用能更有效的去除根管玷污层,且对根管壁表面结构无明显破坏。     

Evaluation of smear layer removal by EDTAC and sodium hypochlorite with ultrasonic agitation

AIM: To evaluate smear layer removal by different irrigating solutions under ultrasonic agitation. METHODOLOGY: Twenty recently extracted mandibular incisors with a single root canal were divided into four equal groups. Three groups were instrumented using the modified double-flared technique, the fourth remained unprepared. Each group was irrigated with either distilled water, 1.0% sodium hypochlorite alone or associated with 15% EDTAC between each file size. The final group was not instrumented but irrigated with 1.0% sodium hypochlorite and 15% EDTAC. A size 15 file energised by ultrasound was used with small amplitude filing movements against the canal walls in all groups. The teeth were split longitudinally and the roots measured to provide three sections of the same size (cervical, middle and apical). Samples were examined under the scanning electron microscope and assessed for the amount of smear layer by three independent and calibrated examiners. The scoring system ranged from 1 (no smear layer) to 4 (all areas covered by smear layer). Due to the non-parametric nature of the data, Friedman's test was used for statistical analysis. RESULTS: Canal walls were covered with smear layer in the group irrigated with 1% sodium hypochlorite alone and the group irrigated with distilled water. Canals irrigated with 1.0% sodium hypochlorite associated with 15% EDTAC had less smear layer throughout the canal (P < 0.001). There were no statistical differences for the amount of smear layer found on the cervical, middle and apical thirds when each group was analysed separately. CONCLUSIONS: Under ultrasonic agitation, sodium hypochlorite associated with EDTAC removed the smear layer from root canal walls, whereas irrigation with distilled water or 1.0% sodium hypochlorite alone did not remove smear layer.     

Effect of 17% EDTA and MTAD on intracanal smear layer removal: A scanning electron microscopic study

The purpose of this study was to determine the effectiveness of MTAD as the final irrigant to remove the smear layer, compared with that of 17% EDTA, both following root canal irrigation with 5.25% sodium hypochlorite (NaOCl). Fifty‐five extracted maxillary and mandibular single‐rooted human teeth were prepared by a crown‐down technique using rotary 0.04 and 0.06 taper nickel‐titanium files. 5.25% sodium hypochlorite was used as the intracanal irrigant. The canals were then treated with 5 mL of one of the following solutions as final rinse: 5.25% sodium hypochlorite, 17% EDTA or MTAD. The presence or absence of smear layer in the coronal, middle and apical portion of each canal was examined with a scanning electron microscope. The results showed that MTAD is an effective final rinse solution for removing the smear layer in canals irrigated with sodium hypochlorite. When 17% EDTA was used as a final rinse, the smear layer was removed from the middle and coronal thirds of canal preparations, but it was less effective in the apical third of the canals.     

去除玷污层对根管微渗漏影响的实验研究

目的评价去除玷污层对根管充填材料密封性能的影响.方法选取60个新鲜拔除的人单根管牙,在釉牙骨质界处切除牙冠.将所有牙根随机分为3组,每组20个.分别用根管充填糊剂加牙胶尖、Vitapex糊剂加牙胶尖和Thermafil糊剂热熔牙胶充填根管;每组中有10个牙根根管预备时保留玷污层,另外10个去除玷污层.用印度墨水染色法对比研究去除玷污层对根管充填材料密封性能的影响.结果牙胶尖加根管充填糊剂组中,保留和去除玷污层组的染色线长度均值分别为3.36±0.42 mm、3.42±0.65 mm;Vitapex加牙胶尖组中,染色线长度均值分别为2.09±0.19 mm、1.70±0.22 mm;Thermafil热熔牙胶组中,染色线长度均值分别为1.05±0.37 mm、0.56±0.11 mm.统计学分析发现3个实验组中,去除玷污层或保留玷污层对根管微渗漏影响的统计学差异均不显著(P>0.05).结论去除玷污层对根管充填材料的密封性能无显著影响.     

Evaluation of SmearOFF,maleic acid and two EDTA preparations in smear layer removal from root canal dentin

Objectives: To evaluate SmearOFF, 7% maleic acid (MA) and two different preparations of ethylenediaminetetraacetic acid (EDTA) in smear layer removal.

Materials and methods: Fifty single-rooted teeth were separated into five groups, instrumented and irrigated as follows: (1) SmearOFF, (2) 7% MA, (3) 18% EDTA (pH 11.4), (4) 17% EDTA (pH 8.5) and (5) 0.9% saline. Teeth samples were blinded and examined by scanning electron microscopy with Image J software.

Results: Eighteen percent EDTA was less efficient when compared to SmearOFF and MA at all thirds of the root canal system. There was no difference between SmearOFF and MA in the coronal and middle thirds. In the apical third, MA removed more smear layer. Seventeen percent EDTA was as efficient as SmearOFF and MA in coronal and middle third but not in the apical third. Eighteen percent EDTA removed smear layer less efficiently in the coronal and middle thirds than 17% EDTA; in the apical third, there was no difference observed. In the saline group, all specimens were heavily smeared. There was no significant difference between 18% EDTA and saline at all canal thirds.

Conclusions: SmearOFF and 17% EDTA (pH 8.5) had better smear layer removal capability in the coronal and middle thirds of the root canal system. In the apical third, 7% MA was superior. 18% EDTA (pH 11.4) and saline had poor smear layer removal ability.     

Scanning electron microscopic investigation of the effectiveness of phosphoric acid in smear layer removal when compared with EDTA and citric acid

Introduction

The smear layer adheres to dentinal surface, thus occluding the dentinal tubules. Because this layer disfavors the penetration of irrigant solutions and root canal fillings, it should be removed. The aim of this study was to compare the effectiveness of 37% phosphoric acid with that of 17% EDTA and 10% citric acid in the removal of smear layer.

Materials and Methods

Fifty-two maxillary single-rooted human canines were accessed and instrumented. Between each instrument used, the canals were irrigated with sodium hypochlorite. After instrumentation, the teeth were irrigated with distilled water and then divided into groups according to the time and substances employed. The substances used were 17% EDTA, 10% citric acid, and 37% phosphoric acid solution and gel. The experimental time periods were of 30 seconds, 1 minute, and 3 minutes. The samples were prepared and observed by means of scanning electron microscopy. Three photomicrographs (2,000×) were recorded for each sample regarding the apical, middle, and cervical thirds. A score system was used to evaluate the images.

Results

None of the substances analyzed in this study was effective for removing the smear layer at 30 seconds. In the 1-minute period, the phosphoric acid solution showed better results than the other substances evaluated. In the 3-minute period, all the substances worked well in the middle and cervical thirds although phosphoric acid solution showed excellent results even in the apical third.

Conclusions

These findings point toward the possibility that phosphoric acid solution could be a promising agent for smear layer removal.     

Assessment of smear layer removal protocols in curved root canals

This study sought to assess if the final rinse protocol interferes with the smear layer removal in the apical area of curved canals. Sixty‐four extracted human mandibular molars with curved mesial roots were instrumented with rotary files and divided into six experimental groups for final rinse: 1EDTA (syringe irrigation with 1 mL of 17% ethylenediaminetetraacetic acid (EDTA) ), 5EDTA (syringe irrigation with 5 mL of 17% EDTA), 1EDTA‐P (syringe irrigation with 1 mL of 17% EDTA + pumping with gutta‐percha point), 5EDTA‐P (syringe irrigation with 5 mL of 17% EDTA + pumping with gutta‐percha point), 1EDTA‐EA (syringe irrigation with 1 mL of 17% EDTA + EndoActivator) and 5EDTA‐EA (syringe irrigation with 5 mL of 17% EDTA + EndoActivator). Final rinsing was carried out over 3 min. The specimens were split lengthwise and observed under a scanning electron microscope using a score criterion. Comparison among the groups showed statistically significant difference only between the 5EDTA‐EA group and the other groups (Kruskal–Wallis and Dunn's post‐hoc tests, P < 0.05). The combination of 5 mL of 17% EDTA and 3 mL of 2.5% sodium hypochlorite (NaOCl) with the EndoActivator removed smear layer from the apical area of curved root canals more effectively than the other protocols used.     

The effect of German chamomile (Marticaria recutita L.) extract and tea tree (Melaleuca alternifolia L.) oil used as irrigants on removal of smear layer: a scanning electron microscopy study

AIM: To compare the cleaning effectiveness of chamomile hydroalcoholic extract and tea tree oil to 2.5% sodium hypochlorite (NaOCl) solution as an intracanal irrigant for the removal of the smear layer. METHODOLOGY: Forty extracted, single-rooted, mature, permanent, human teeth were allocated at random into one of three experimental groups of ten teeth and two control groups of five teeth. For each tooth, the pulp chamber was accessed and the canal prepared using K-type files and Gates-Glidden burs, using a step-back technique; the apical stop was prepared to a size 30. Each canal was subsequently irrigated with one of the following solutions: distilled water (as a negative control), 2.5% NaOCl + 17% ethylenediamine tetraacetic acid (EDTA) (as a positive control), chamomile or tea tree oil or 2.5% NaOCl. Each tooth was split longitudinally and prepared for examination by scanning electron microscopy (SEM). The quantity of smear layer remaining on the three levels of each canal (coronal, middle and apical) was examined using magnifications of 2000 and 5000x. The data were analysed using nonparametric Kruskal-Wallis and Mann-Whitney U-tests. RESULTS: The most effective removal of smear layer occurred with the use of NaOCl with a final rinse of 17% EDTA (negative control) followed by the use of a chamomile extract. Chamomile extract was found to be significantly more effective than distilled water and tea tree oil (P < 0.008).The use of a 2.5% NaOCl solution alone, without EDTA and that of tea tree oil, was found to have only minor effects. There was no statistical difference between distilled water, 2.5% NaOCl and tea tree oil. CONCLUSIONS: The efficacy of chamomile to remove smear layer was superior to NaOCl alone but less than NaOCl combined with EDTA.     

The efficacy of Salvadora persica extract in the elimination of the intracanal smear layer: A SEM study

AimTo evaluate the efficacy of an ethanolic Salvadora persica extract in removing the smear layer following a root canal procedure.MethodsSixty extracted, single-rooted human teeth were cleaned, shaped, and divided into four groups. Experimental groups 1 (n = 20) and 2 (n = 20) were irrigated with 1 mg/ml and 5 mg/ml of S. persica, respectively. The positive controls (n = 10) were irrigated with 17% ethylenediaminetetraacetic acid (EDTA), while the negative controls (n = 10) were irrigated with saline. Approximately 5 ml of the irrigating solution was delivered into the root canals for 5 min, and the final rinse was performed with 5 ml of 1% sodium hypochlorite. Scanning electron microscopy was used to evaluate the endodontic smear layer removal at the coronal, middle, and apical thirds of the specimens.ResultsA significant difference in smear layer removal between groups 1 and 2 at the coronal and middle thirds of the canal was observed, and no significant difference was seen between group 2 and the positive control at the coronal third. At the apical third, both concentrations of S. persica had similar effects and were less effective than the positive control in removing the smear layer.ConclusionThe 5 mg/ml S. persica solution was significantly more effective than the 1 mg/ml solution. In addition, the 5 mg/ml S. persica solution was as effective as 17% EDTA in removing the smear layer from the coronal third of the canal wall.     

17% EDTA与脉冲Nd：YAG激光去除根管壁玷污层疗效的电镜研究

目的对17%EDTA与脉冲Nd：YAG激光对根管壁玷污层清除效果进行分析与比较。方法选取30颗新鲜单根成人离体牙,根管机械预备后随机分为三组,每组10例,分别给予5.25%NaClO冲洗（对照组）、17%EDTA＋5.25%NaClO冲洗以及5.25%NaClO冲洗＋Nd：YAG激光照射处理后,电镜下观察根管侧壁玷污层去除情况。利用计算机图像分析软件计算开放牙本质小管口面积/牙本质面积比。统计学方法采用单因素方差分析,α=0.05。结果EDTA冲洗及Nd：YAG激光照射后均可使根管侧壁玷污层明显减少,但EDTA冲洗对牙本质小管口开放作用明显优于Nd：YAG激光照射组及对照组（P〈0.01）。结论17%EDTA对根管壁玷污层的清除效果优于脉冲Nd：YAG激光,适合于临床广泛应用。     

不同浓度EDTA对桩冠固位力的影响及电镜观察

目的 评价不同浓度ＥＤＴＡ对桩冠固位力的影响。方法 采用四种不同浓度的ＥＤＴＡ（５％、１０％、１５％、１７％）对根桩粘接前的６０个离体人牙根管面进行根管玷污层清洁处理,对根管玷污层去除情况及粘固后粘接剂与根管壁的结合度进行了扫描电镜观察;同时还比较了不同浓度ＥＤＴＡ处理后,用磷酸锌粘固剂予以粘固的根桩的抗张强度。结果 从电镜和机械力学的观察,不同浓度的ＥＤＴＡ对桩冠固位力及根管玷污层去除程度有不同     

Effect of different concentrations of EDTA on smear removal and collagen exposure in periodontitis-affected root surfaces

Abstract The purpose of the present study was to explore the possibility of obtaining an acceptable smear-removing and collagen-exposing effect following EDTA etching with concentrations lower than super saturation (24%). A flat den-tin surface was created on human teeth extracted due to severe periodontitis. The teeth were etched with the following concentrations of EDTA for 2 min: 1.5% (group I). 5% (.group II), 15% (group III) and 24% (group IV). and evaluated with scanning electron microscopy with respect to smear layer removal and exposure of root-associated collagen fibers. It was found that neither 1.5% nor 5% EDTA etching was sufficient to dissolve the smear layer to any higher degree. Etching with 15% EDTA dissolved the smear more effectively than the lower concentrations and collagen fibers were sparsely found. Following etching with 24% EDTA (group IV), significantly less smear was seen on the dentin surfaces than in any of the other groups and collagen fibers were seen covering the entire inter-tubular dentin surfaces. Based on these findings, the concentration of EDTA should be somewhere between 15 to 24% in order to obtain an acceptable smear removing and collagen-exposing effect within a clinically acceptable time period.