Reliability of assessing dye penetration along root canal fillings using methylene blue

Methylene blue (MB) remains the most frequently used tracer for dye penetration tests of endodontic fillings, despite its chemical reactions with different materials. This study checked whether dye penetration displayed by MB is comparable to Rhodamine B (RB). One hundred and seventy‐two root canals were filled with gutta‐percha and six sealers. Samples were covered with nail varnish except for the apical area, and immersed in MB or RB solutions under negative pressure. After 24 h, roots were bisected, photographed and the maximal dye penetration recorded. Dye penetrations displayed by MB and RB were compared (Newman–Keuls test). MB and RB displayed comparable results for groups filled with AH Plus, EndoREZ and Polifil (P > 0.05). For Endofill, Sealer 26 and Sealapex, a significant lower dye penetration was observed when MB was used (P < 0.05). Laboratory tests using MB for measuring dye penetration through filled root canals can result in misleading conclusions.     

Fluid transport and dye penetration along root canal fillings

Dye penetration along root canal fillings may be hindered by the presence of entrapped air. In this study, the sensitivity of a dye penetration method was compared with that of a fluid transport model. Sixty root sections from human maxillary central incisors were prepared and obturated by a modified technique to ensure a slight amount of leakage, and divided into three equal groups. Twenty root sections were first mounted in a fluid transport device and assessed for fluid transport under 10 kPa (0.1 atm.) pressure. Another 20 root sections were mounted in the same device before being subjected to air transport under the same pressure. The remaining 20 root sections were not exposed to fluid or air transport. Then, all the 60 root sections were assessed for penetration of a 2% methylene blue solution. The results showed that fluid transport was a much more sensitive method of detecting voids along root canal fillings than dye penetration. After fluid transport for 3 h under low pressure, to eliminate entrapped air, dye penetrated significantly deeper than without previous fluid transport, which suggested that entrapped air in voids along the root canal filling prevented dye penetration.     

Fluid transport and bacterial penetration along root canal fillings

Convective transport of water from the coronal to the apical end of obturated root canals was determined by the movement of an air bubble in a capillary glass tube connected to the apex of the experimental root section using a headspace pressure of 120 kPa (1.2 atm). Water transport through existing voids in the obturated canals could be measured reproducibly in this way. The root canals of 60 human maxillary canines were filled with gutta-percha and sealer by the cold lateral condensation technique. Thirty of these were first exposed to a small motile bacterium, Pseudomonas aeruginosa, growing in a reservoir at the coronal end of each root. After 50 days, two specimens allowed penetration of bacteria to a reservoir at the apical end. All the roots were then assessed quantitatively for convective transport of water. The results were divided into three defined categories: 39 obturated canals were in the‘bacteria tight’category, 14 canals in the 'slight leakage’and 7 canals in the‘gross leakage’category. The two specimens that showed bacterial penetration fell into the slight and gross leakage categories. The previous test for bacterial passage did not statistically influence the fluid transport pattern of these roots which was measured subsequently. These findings indicate that fluids transport through obturated root canals, most of which do not allow the passage of bacteria.     

Periapical status and quality of root fillings and coronal restorations in an adult Spanish population

AIM: To investigate the quality of root fillings and coronal restorations and their association with periapical status in an adult Spanish population. METHODOLOGY: A total of 180 subjects, aged 37.1 +/- 15.7 years, who presented as new patients at the Faculty of Dentistry, Seville, Spain, were examined. All participants underwent a full-mouth radiographic survey incorporating 14 periapical radiographs. The periapical region of all root filled teeth, excluding third molars, were examined. The technical quality of root fillings was evaluated in terms of length in relation to the root apex and lateral adaptation to the canal wall. Radiographic signs of overhang or open margins associated with coronal restorations were also evaluated. Periapical status was assessed using the Periapical Index score. Statistical analyses were conducted using the Cohen's kappa test and logistic regression. RESULTS: The total number of root filled teeth was 93, and 60 (64.5%) had apical periodontitis (AP). Presence of AP in root filled teeth was associated with inadequate adaptation of the filling (OR = 2.29; P = 0.06), inadequate length of the root filling (OR = 2.44; P = 0.048), and with poor radiographic quality of the coronal restoration (OR = 2.38; P = 0.054). Only 34.4% of the root fillings were adequate from a technical perspective. When both root fillings and coronal restorations were adequate the incidence of AP decreased to 31.3% (OR = 5.50; P < 0.01). CONCLUSIONS: The incidence of AP in root filled teeth was high. Many root fillings were technically unsatisfactory. Adequate root fillings and coronal restorations were associated with a lower incidence of AP; an adequate root filling had a more substantial impact on the outcome of treatment than the quality of the coronal restoration.     

An evaluation of the influence of passive ultrasonic irrigation on the seal of root canal fillings

AIM: To evaluate the influence of passive ultrasonic irrigation (PUI) on the seal of root canal fillings. METHODOLOGY: A total of 40 mandibular premolars were distributed equally into two groups and the root canals were cleaned and shaped; they were then filled with gutta-percha and AH26 (sealer) using the warm vertical compaction technique with the System B (Analytic Technology, Redmond, WA, USA) device. In one group PUI was applied, after completion of instrumentation and hand-irrigation. In the other group, PUI was not applied. Thereafter, leakage of glucose was evaluated by measuring its concentration once a week for a total period of 56 days using a glucose penetration model. Differences between the groups in terms of glucose concentrations were statistically analysed with the Mann-Whitney test; the level of significance was set at P=0.05. RESULTS: After the first month the root fillings in teeth where PUI had been used, sealed the root canal significantly better than in teeth where no PUI had been used (P=0.017). CONCLUSION: Root fillings sealed the root canal better when PUI had been used.     

Sealing ability of potential retrograde root filling materials

Abstract The sealing ability of two potential retrograde root filling materials, a light-cured glass ionomer cement (Vitrebond) and a reinforced zinc oxide-eugenol cement (Kalzinol) was compared with that of amalgam using three methods of assessment: bacterial leakage, confocal microscopy and Indian ink leakage. The root canals of 80 extracted human single-rooted teeth were prepared. All the teeth were apicected, retrograde cavities were prepared and then divided into four equal groups of 20 teeth. The teeth were sterilised by autoclaving and the retrograde cavities filled with the test materials. In the control group, retrograde cavities in 10 teeth were left unfilled while cavities in another 10 teeth were sealed with cyanoacrylate cement. The teeth were first subjected to a bacterial leakage test using Enteroccocus faecalis as a leakage marker. After which, the adaptation of the retrograde root fillings was assessed using a confocal optical microscope. Finally, the teeth were processed for the Indian ink leakage test. Bacterial leakage occurred in more teeth filled with amalgam compared with both Vitrebond and Kalzinol (P < 0.001), between which there were no differences. With confocal microscopy, the size of the marginal gap was largest with amalgam and smallest with Vitrebond; all differences were statistically significant (P < 0.001). Finally, there was more Indian ink penetration with amalgam compared with both Vitrebond and Kalzinol (P < 0.001) but there were no differences between Vitrebond and Kalzinol. Although there were individual differences within samples, overall, the three methods of assessment produced similar results. The sealing ability of Vitrebond and Kalzinol was similar and both materials were better than amalgam.     

Influence of tooth age and root section on root dentine dye penetration

Aim To investigate dye permeability of root dentine according to patients’ age, root section and dye penetration time. Methodology A total of 96 extracted human single‐rooted teeth, assigned to four age groups (<30, 30–45, 45–60 and >60 years) were separated at the cemento–enamel junction and root canals were enlarged. The root surfaces were coated with cyanocrylate to prevent external dye penetration and centrifuged in distilled water to eliminate air. For dye penetration the root canals were filled with methylene blue 5%. After 1, 30 and 60 days eight roots per age group were cross‐sectioned in 1 mm slices. Dye penetrated areas and the complete dentine areas were digitized and measured. Differences between groups were judged with anova and LSD, P < 0.05 or P < 0.01. Results The root section, the patients’ age and the penetration time influenced significantly the penetrated areas (P < 0.05). After 1 and 30 days significant differences could be found only in the apical root sections between all age groups (P < 0.05). Dye penetration areas systematically decreased with increasing age and also from coronal to apical (P < 0.01). Conclusions Age influenced dye penetration significantly. Dye penetration also depended on the location (coronal, middle and apical) within the root canal. These findings indicate that there may be a correlation between the tooth age and permeability of root dentine, which may influence the distribution and effectiveness of drugs used for root canal disinfection.     

A comparison of the apical dye penetration patterns shown by methylene blue and India ink in root-filled teeth

This study compared the linear leakage patterns shown by 5% aqueous solution of methylene blue (MB) and India ink (II). One-hundred and twenty-five roots with single canals from extracted human teeth were used. The canals were cleaned and shaped using the step-back technique under copious irrigation. Three groups were arranged to receive root fillings of gutta-percha and one of three proprietary sealers using standard lateral condensation techniques: Sealapex (40 roots), Tubli-Seal (40 roots) and Ketac-Endo (20 roots). The remaining roots were used as controls: positive with gutta-percha and no sealer and negative with the apices sealed with nail varnish. The roots were randomly selected for 7-day immersion in either MB or II, then sectioned longitudinally; dye penetration was assessed using a Wild Leitz stereomicroscope. In all groups MB showed more penetration than II. The results were statistically significant at the P= 0.01 level, with the exception of the positive control groups. Negative controls showed no penetration. It is concluded that MB, which has a low molecular weight penetrated more deeply along root canal fillings than II, which has a large particle size.     

Post‐treatment apical periodontitis related to the technical quality of root fillings and restorations in Thai population

The aim of this study was to investigate the post‐treatment apical periodontitis in endodontically treated teeth related to the technical quality of root fillings and restorations in Thai population. Full‐mouth periapical radiographs from Thai patients attending the Faculty of Dentistry, Mahidol University, Thailand were examined. The periapical status, quality of root fillings and coronal restorations, existence of intraradicular post and its relationship to the root fillings were evaluated. Among 1586 patients, 37.4% presented endodontically treated teeth. The total number of endodontically treated teeth was 1511, and 35% presented apical periodontitis. Combined data for root filling and coronal restoration qualities revealed significantly better outcome in teeth with adequate qualities of both parameters than the other combinations (P < 0.001). The prevalence of post‐treatment apical periodontitis among Thai population was relatively high and significantly associated with substandard technical quality of root fillings and restorations.     

Time‐dependence of coronal seal of temporary materials used in endodontics

The aim of this in vitro study was to compare parametrically the coronal seal ability over different periods of times of four restorative materials used to seal the pulpal access cavity after endodontic treatment. One hundred and thirty‐five mandibular premolars were divided randomly into three time groups (1, 2 and 4 weeks), each of which was in turn divided into four subgroups. Each subgroup was restored using one of four restorative materials: Coltosol, glass ionomer cement (GIC), zinc phosphate (ZP) cement, or intermediate restorative material (IRM) cement. The root canals were prepared using the crown‐down technique, and obturated using lateral condensation. Following placement of the restorative material, the samples were incubated in distilled water at 37°C and were subjected to 50 thermocycles (0 ± 4, 56 ± 4C). After immersing in (2%) methylene blue dye for 24 h, teeth were longitudinally sectioned and examined under a stereomicroscope. The results showed that Coltosol and GIC cement were significantly superior in sealing ability to ZP and IRM cements (P < 0.05). There was no significant difference between GIC cement and Coltosol. Both Coltosol and GIC after 1 week were significantly better than 4 weeks. There was no significant difference in the seal ability at different time periods when ZP and IRM cements were used.     

The annual frequency of root fillings, tooth extractions and pulp-related procedures in Danish adults during 1977-2003

AIM: To investigate a hypothesized long-time decrease of endodontic treatment in a population with low caries prevalence. METHODOLOGY: A Danish nationwide database including almost all dental diagnostic, prophylactic and therapeutic procedures performed in Danish adults was available. Data on the annual frequencies of root fillings, extractions, pulpotomies, direct pulp cappings and stepwise excavations between 1977 and 2003 were analysed. Data on pulpal and periapical diagnoses were not available and on patients age and gender only from 1996. RESULTS: Between 1977 and 2003 the annual number of root filled canals increased from 268,223 to 364,867 (36%). The annual number of root filled teeth increased from 160,119 to 191,803 (20%). During the period, the annually registered patients increased by 16%. Calculated per 1000 patients, the number of root fillings showed a statistically significant increase of 17%. In root filled teeth the canal/tooth ratio increased from 1.67 to 1.96. Root fillings were frequently recorded in all age groups with the bulk of treatments performed on patients between 40 and 60 years of age. At a total population level, the rate of root fillings decreased among younger individuals and increased among older. The annual number of tooth extractions was more than halved from 656,624 in 1977 to 346,490 in 2003. Pulpotomies decreased markedly over the period and less than 10 treatments per 1000 patients were noted for pulp capping as well as stepwise excavation procedures. CONCLUSIONS: The present study failed to show a long-time decrease of endodontic treatment in a population with low caries prevalence. On the contrary, an increase of root filled canals was observed between 1977 and 2003, which was probably due to a reduction of the tooth extraction rate and an increased treatment of multi-rooted teeth.     

Leakage along warm gutta-percha fillings in the apical canals of curved roots

Abstract – The aim of this study was to investigate the leakage along the apical portion of warm gutta‐percha obturated curved canals. Human mandibular premolars with single, curved (21°–40°) canals were prepared using the Lightspeed technique. Two groups of prepared canals, matched according to curvature and prevalence of apical transportation, were obturated by two techniques. Coronal gutta‐percha was removed immediately after root obturation was completed to simulate the procedure for post space preparation. Leakage along the apical 3 mm of root filling was measured with a fluid transport device. Vertical condensation of warm gutta‐percha and Pulp Canal Sealer provided less leakage than Thermafil plastic obturators and AH26 sealer (P=0.002).     

Technical quality of root canal fillings performed in a dental school and the associated retention of root-filled teeth: a clinical follow-up study over a 5-year period

Summary  The aim of this study was to examine the technical quality of root canal fillings performed in a dental school and to investigate the associated effect on the survival/retention of root-filled teeth. A review of case notes of patients who had root canal treatment performed in the department of Restorative Dentistry, University Dental School and Hospital, Cork, Ireland was carried out. The technical quality of the root canal filling was described according to its relationship with the radiographic apex on a post-treatment radiograph. Tooth status at review was defined as 'tooth present' or 'tooth absent' based on the presence or absence of the root-filled tooth recorded in the treatment records at a review appointment following placement of the root canal filling. One hundred and forty-eight teeth (129 patients) were considered. Of these, 69·6% ( n  = 103) were of acceptable technical quality, 23·6% ( n  = 35) were under-extended, and 6·8% ( n  = 10) were overextended. An increased number of intra-treatment radiographs to confirm the relationship of the canal preparation to the radiographic apex and operator experience were significant predictors of adequate root canal fillings ( P  < 0·05). Eighty-three per cent ( n  = 123) of teeth were present at a review appointment held an average of 40 months following completion of treatment (12–60 months). The technical quality of the root canal filling was the only significant factor in predicting tooth survival ( P  < 0·05), while the presence of pre-treatment periapical pathology had no significant effect on survival of the root-filled tooth. Determination and maintenance of the working length of the canal system is an important feature in producing good quality root canal fillings, which in turn, is associated with increased likelihood of survival/retention of root-filled teeth.     

Leakage evaluation of three different root canal obturation techniques using electrochemical evaluation and dye penetration evaluation methods

The aim of this study was to compare the apical sealing ability of three different obturation techniques using an electrochemical evaluation and evaluating dye penetration. One hundred and thirty-two maxillary anterior teeth were randomly divided into six groups. There were 20 teeth in each group. The teeth were obturated as follows: Groups 1 and 4 with Thermafil, Groups 2 and 5 with System B, and Groups 3 and 6 with cold lateral condensation (CLC). The apical leakage in these groups was evaluated using an electrochemical method for Groups 1, 2, 3 and a dye penetration method for Groups 4, 5 and 6. In both methods, the lowest mean leakage values were observed for Thermafil and the highest were observed for the CLC groups. The difference between Thermafil and CLC was statistically significant (P < 0.05). In both groups, System B fillings showed moderate leakage and the difference was not significant with Thermafil and CLC groups.     

连续波热牙胶充填后不同时机桩腔预备对根尖封闭性的影响

目的 评价连续波热牙胶充填后不同时机桩腔预备对根尖封闭性的影响。方法 50颗单根管牙,采用冠向下法,使用ProTaper机用镍钛系统预备根管。随机选择5颗牙为阴性对照组,5颗牙为阳性对照组。另40颗牙随机分为A、B、C、D4组,每组10颗,所有根管均使用连续波热牙胶充填术充填根管,阳性对照组不使用根管封闭剂,然后A、B、C、D组分别于根充后即刻、3d、7d、30d四个不同时间点进行桩腔预备。采用葡萄糖定量法测定第2、7、14、21、28d从冠方向根方渗漏的葡萄糖量。结果 从第14d起即刻桩腔预备组与延迟桩腔预备三组相比,葡萄糖渗漏量均有显著性差异(P<0.05),而实验期间延迟桩腔预备三组之间相比没有统计学差异(P>0.05)。结论 延迟桩腔预备会削弱充填材料和封闭剂封闭根管的能力。     

In vitro analysis of the penetration of methylene blue dye in human radicular dentin using different methods of impregnation

The purpose of the present study was to verity whether different conditions of contact with a dye solution would result in different levels of the impregnation by the marker agent in human radicular dentin. The root canals of 60 upper human canines were immersed in methylene blue dye (0.5%, pH 7.0) for 24 h under six different conditions: passive immersion; pre‐agitation for 10 min using an endodontic ultrasound; pre‐agitation for 10 min using a cleaning ultrasound; 25‐mmHg vacuum for 10 min followed by passive immersion; 30‐mmHg and 650‐mmHg vacuum for 24 h. The roots were longitudinally sectioned and dye impregnation was assessed by a trained and calibrated examiner, using the Q 550 IW image analyser (Leica Qwin?, Cambridge, England). The measurements were analysed with anova and Tukey test. The results revealed no significant difference among the different methods for dye impregnation. In the cervical third, impregnation with 30 mmHg was significantly more effective than with endodontic ultrasound or 25 mmHg. At the apical third, no differences were observed between any of the dye impregnation methods. The comparison of different thirds revealed a statistically significant difference between the cervical and apical and the middle and apical thirds, but not between the cervical and middle thirds.     

Bacterial penetration along different root canal filling materials in the presence or absence of smear layer

AIM: To study the effect of the smear layer on the penetration of bacteria along different root canal filling materials and to examine the dentine/sealer and sealer/core material interfaces for the presence of bacteria. METHODOLOGY: A total of 110 human root segments were instrumented to size 80 under irrigation with 1% sodium hypochlorite. Half of the roots were irrigated with a 5-mL rinse of 17% EDTA. Roots with and without smear layer were filled with gutta-percha (GP) and AH Plus sealer (AH), GP and Apexit sealer (AP), or RealSeal cones and sealer (RS). Following storage in humid conditions at 37 degrees C for 7 days, the specimens were mounted into a bacterial leakage test model for 135 days. Survival analyses were performed to calculate the median time of leakage and log-rank test was used for pairwise comparisons of groups. The level of significance was set at P = 0.05. Selected specimens were longitudinally sectioned and inspected by scanning electron microscopy for the presence of bacteria at the interfaces. RESULTS: In the presence of the smear layer, RS and AP leaked significantly more slowly than in its absence. In the absence of the smear layer, AH leaked significantly more slowly than RS. SEM results indicated a differential pattern of bacterial penetration among the sealers. CONCLUSIONS: Removal of the smear layer did not impair bacterial penetration along root canal fillings. A comparison of the sealers revealed no difference except that AH performed better than RS in the absence of the smear layer.     

Structure of experimental in vitro and in vivo lesions around composite (Addent XV®) fillings

abstract — In the in vitro experiments of the present study Class V Addent XV® fillings were inserted on buccal surfaces of 32 permanent human teeth. Lesions were produced by placing acidified gelatin around the fillings. In the corresponding in vivo experiments, caries was produced around similar fillings in 17 permanent teeth. In both series, sections of the teeth with the fillings in situ were studied by polarized light microscopy and microradiography. All teeth showed "outer lesions", but the tendency to development of "cavity wall lesions" was negligible. A comparison with lesions produced previously in corresponding experiments with silver amalgam and silicate fillings has been done.