Comparison of apical leakage in root canals obturated with various gutta percha techniques using a dye vacuum tracing method

Nair P, Gowri S, Jayaprakash K. Comparative evaluation of fracture resistance of endodontically treated bicuspids instrumented with hand files, trunatomy, protaper next, protaper gold, and waveone – An In vitro study

Aim:

The study aims to compare and evaluate the fracture resistance of endodontically treated bicuspids instrumented with Hand Files, TruNatomy (TRN), ProTaper Next (PTN), ProTaper Gold (PTG), and WaveOne (WO).

Materials and Methods:

In total, 45 extracted single-rooted human premolar teeth were selected and sectioned at or below the cementoenamel junction to obtain roots 15 mm long. The samples were divided into four experimental groups and one control group (n = 9): instrumentation with nickel–titanium (NiTi) Hand Files (control group), instrumentation with TRN files, instrumentation with PTN files, instrumentation with PTG files, and instrumentation with WO files. The samples were obturated by lateral compaction technique using gutta-percha points and AH Plus sealer. A vertical load was applied to the tooth using the universal testing machine (Tecsol-TSI-BDS-2Kn-Sr No. 170710) for the fracture resistance test. Statistical analysis was performed.

Results:

The study reported that teeth instrumented with NiTi hand files exhibited the highest fracture resistance when compared to all the rotary and reciprocating file systems. Among rotary and reciprocating instruments, root prepared with TRN files showed the most significant resistance to fracture compared with PTN, PTG, and WO files.

Conclusion:

Within the limitations of this study, it can be concluded that minimally invasive instrumentation of the system preserves more pericervical dentin, which may increase the resistance to fracture. Results of this study and other studies support the use of minimally tapered instruments to improve the fracture resistance of endodontically treated teeth.

An In Vitro Comparative Evaluation of Distribution of Three Different Sealers by Single-Cone Obturation Technique

Aim:

The aim of this study was to evaluate the distribution of sealer at different levels of the root canal using three different sealers in a single-cone obturation technique.

Materials and Methods:

Thirty freshly extracted mandibular premolar teeth were selected and access opening was performed. Working length was determined. Cleaning and shaping were done till 25 size K file followed by ProTaper till F2 size. Teeth were then obturated with matching gutta-percha points with the following sealers: Group I, 10 teeth with zinc oxide eugenol sealer; Group II, 10 teeth with AH plus sealer; and Group III, 10 teeth with NanoSeal-S sealer. Teeth were cross sectioned at 3 and 6 mm from the apex. Color photographs of sections were taken at a magnification of ×40 using a camera connected to a stereo-operating microscope and the images were transferred to a computer. Sealer distribution was observed and the canal perimeters coated or uncoated with the sealer can be calculated using a computer digital imaging system.

Results:

Of the three groups, zinc oxide eugenol showed least sealer distribution. AH Plus and Nanoseal-S showed no significant difference between the distribution at the 3- and 6-mm levels.

Conclusion:

Both AH Plus and Nanoseal-S showed excellent sealer distribution when compared to zinc oxide eugenol.

Influence of Post Space Preparation on the Apical Leakage of Calamus, Single-Cone and Cold Lateral Condensation Obturation Techniques: A Computerized Fluid Filtration Study

PURPOSE

Apical microleakage between the root canal and periapical tissues is considered a common cause of endodontic failure. The aim of this study was to evaluate the apical microleakage of various obturation techniques after immediate post space preparations with different drills.

MATERIALS AND METHODS

One hundred twenty human single-rooted teeth were selected for this study. The coronal portions were removed to achieve a uniform length of 15 mm. All root canals were instrumented with ProTaper Next rotary files using crown-down technique. The 120 roots were randomly assigned to 3 experimental groups according to obturation technique (n = 40). The root canals were obturated with lateral condensation in group 1, single-cone technique in group 2, and Calamus 3D obturation system in group 3. Each group was divided into two subgroups (n = 20) according to drill types (Gates Glidden and Peeso drills) leaving 5 mm of apical gutta-percha. The apical microleakage was measured using the computerized fluid filtration meter method. The results were evaluated using Kruskal-Wallis test with Bonferroni Corrected Mann-Whitney U multiple comparison post hoc tests.

RESULTS

There was no statistically significant difference between obturation techniques after post space preparation with Peeso drills (p > 0.05). In Gates Glidden drill groups, single-cone technique demonstrated higher leakage (0.0051 ± 0.0037 μl x min^-1 × cmH₂ O^-1 ) than Calamus techniques (0.0019 ± 0.0012 μl x min^-1 × cmH₂ O^-1 ) (p < 0.017).

CONCLUSIONS

Gates Glidden drills caused the highest apical leakage in teeth obturated with single-cone technique.

A Prospective Randomized Comparative Study of Cold Lateral Condensation Versus Core/Gutta-percha in Teeth with Periapical Lesions

INTRODUCTION

The aim of this study was to compare the outcome of root canal treatment using either Thermafil (TF; Dentsply Maillefer, Ballaigues, Switzerland) or the cold lateral condensation (CLC) obturation technique in teeth with periapical lesions and to investigate the influence on postoperative pain and treatment outcomes.

METHODS

After standardized root canal preparation technique, 112 teeth were obturated with either the TF or the CLC technique during 2 sessions by single operator. Postoperative pain, obturation length, and treatment outcomes were recorded. The teeth were reviewed clinically and radiographically for 2 years.

RESULTS

Although there were no significant differences between the techniques in the incidence of postoperative pain at 24 hours (P > .05), the incidence of pain was significantly higher in the TF group than in the CLC group at 48 hours (P < .05). During the 2-year follow-up period, there was no statistically significant difference in the success rate of the teeth treated with TF (96.4%) in comparison with those treated with CLC (98.2%) (P > .05).

CONCLUSIONS

In this study, the outcome of the root canal treatment of teeth using the TF and CLC techniques revealed that these techniques are useful for root canal obturation.

Comparison of root canal sealer distribution in obturated root canal: An in-vitro study

BACKGROUND AND OBJECTIVES

Endodontic sealer is currently regarded with such importance in the root canal treatment that it is often considered to be more important than the core obturating material itself. Sealer with the least film thickness is favorable for minimizing microleakage. The aim of the study is to compare sealer distribution in root canal using three different sealers with three different obturation techniques.

MATERIALS AND METHODS

AH plus, Fuji-1, Tubliseal Extended Working Time (EWT) was placed into the prepared root canals of 90 maxillary central incisors using a lentulospiral. Thereafter, the canals were obturated using three different gutta-percha root filling techniques (single cone, lateral condensation, vertical condensation). Horizontal sectioning was carried out at 3 mm and 6 mm from the apex with a diamond disk. The two specimens thus obtained were examined for sealer distribution using a stereomicroscope and the percentage of sealer coating the perimeter (PSCP) was calculated using a digital imaging system.

RESULTS

A significant difference existed in the mean PSCP values of three different sealers (P < 0.000), where Tubliseal (EWT) had the highest PSCP values followed by the AH plus and Fuji-1. Also, between techniques, differences were observed (P < 0.00), where a single cone technique had the highest mean values followed by lateral condensation and vertical condensation. Between the 3 mm and 6 mm sections a non-significant difference was observed (P < 0.945).

CONCLUSION

Tubliseal EWT showed highest PSCP value and Single cone technique showed the higher PSCP value then lateral and vertical condensation technique at 3 mm and 6 mm sections.

Dentinal defects before and after rotary root canal instrumentation with three different obturation techniques and two obturating materials

Aim:

To evaluate the role of rotary root canal instrumentation followed by obturation with three different techniques and two different materials on the incidence of dentinal defects.

Materials and Methods:

One hundred and sixty mandibular premolars were divided into eight groups (n = 20). Group I was left untreated and served as control. The other seven groups were prepared with profile rotary instruments till #40.06 taper. After preparation, group II was left unfilled, groups III, IV, and V were obturated with Gutta-percha and AH Plus sealer using passive technique, lateral compaction and warm vertical compaction, respectively. Groups VI, VII, and VIII were obturated with Resilon and Realseal sealer using passive technique, lateral compaction, and warm vertical compaction, respectively. Roots were then sectioned at 3, 6, and 9 mm from the apex and inspected under a stereomicroscope (50×) for dentinal defects. Chi-square test was performed to compare the incidence of dentinal defects between the groups (P < 0.05).

Results:

The unprepared control group had no dentinal defects. The instrumentation group (group II) and the obturation group (groups III-VIII) showed significantly more defects than the uninstrumented control group (group I) (P < 0.001). There was no significant difference between the root canal obturating techniques (group III-VIII) when compared with the instrumentation group (group II). On inter group comparison among the obturation groups the number of defects after lateral compaction with Gutta-percha (group IV) was significantly larger than passive Gutta-percha obturation (group III) (P < 0.05).

Conclusions:

The results suggest that root canal instrumentation significantly influenced the incidence of dentinal defects or fracture. Dentinal defects were more significantly attributed to the role of root canal instrumentation rather than the type of obturation technique or material. Lateral compaction with Gutta-percha significantly produces more defects than passive Gutta-percha obturation.

Carrier-based root canal filling materials: a literature review

A review of the literature on the use of carrier based obturation materials focusing on Thermafil and Resilon based obturator (RealSeal 1) are presented in this article. The review addressed the history, apical leakage, coronal leakage, biocompatibility, sealing ability and clinical success of Thermafil and RealSeal 1. Based on the studies gathered, this review concluded that both treatment techniques (Thermafil and RealSeal 1) did not provide excellent apical sealing ability. More research should be done to try to overcome their main drawback, its sealing ability.

Vertical root fractures and dentin defects: effects of root canal preparation, filling, and mechanical cycling

INTRODUCTION

The aim of this study was to evaluate the ex vivo effects of root canal preparation, filling techniques, and mechanical cycling (MC) on the incidence of dentin defects and vertical root fractures (VRFs).

METHODS

Seventy extracted single-rooted teeth were divided into 6 groups. The first 2 groups were the unprepared and unprepared/MC groups. The other groups were prepared by using Gates Glidden drills and ProTaper Universal files up to F3 and were grouped according to the following: prepared teeth and the absence of root canal filling, passive technique, lateral compaction, and Tagger's hybrid technique. All of the groups except the unprepared group were subjected to MC (1,000,000 cycles, 90 N, 4 Hz, 37°C). The roots were then sectioned horizontally at 3, 6, and 9 mm from the apex and observed under a ×10 stereomicroscope. The defects were categorized as no defect, vertical root fracture, and other defects. The differences between the groups were analyzed by using the Fisher exact and χ(2) tests.

RESULTS

MC by itself did not influence the incidence of dentinal defects (P > .05, between the unprepared and unprepared/MC groups). The filled groups presented a similar incidence of other defects (P > .05), although VRFs were observed only when the MC was associated with pressure filling techniques (the lateral compaction and Tagger's hybrid groups).

CONCLUSIONS

MC by itself did not induce VRF. When associated with apical pressure filling techniques, however, VRF occurred in 13.3% (lateral compaction) and 33.3% (Tagger's hybrid) of the cases.

An in vitro assessment of apical microleakage in root canals obturated with gutta-flow, resilon, thermafil and lateral condensation: A stereomicroscopic study

Aim:

The purpose of this study was to evaluate and compare the apical microleakage of Resilon to Thermafil, Gutta-flow and Cold lateral condensation using a dye penetration method.

Materials and Methods:

Sixty extracted human maxillary single rooted teeth with intact roots were selected. Decoronation was followed by canal preparation upto ISO size 50. Teeth were then randomly divided into four groups for obturation. Group I – Cold lateral condensation with AH Plus, Group II – Gutta-flow with master cone, Group III– Thermafil with AH Plus, Group IV– Resilon with Self-etch epiphany. Apical microleakage was assessed by dye penetration test under stereomicroscope.

Result:

The result was analyzed statistically and showed that Resilon provides a best seal. Gutta-flow exhibited maximum microleakage. All the four groups at some level or the other exhibited some percentage of microleakage.

Conclusions:

None of the methods showed a fluid-tight seal.

Assessment of the apical seal of root canals using different filling techniques

The aim of this study was to investigate the apical leakage of roots filled by three different gutta-percha techniques: lateral condensation, Tagger's hybrid and E&Q Master. Forty-two extracted single-rooted teeth were used. The coronal part of each tooth was removed and the root received biomechanical preparation using a 60-K file. The roots were randomly divided into three groups according to the technique of filling the root canal: Group I, lateral condensation; Group II, Tagger's hybrid; Group III, E&Q Master. The roots were submitted to dye leakage test with Rhodamine B for 7 days, using vacuum during the initial 30 min. The teeth were sectioned longitudinally and the leakage was measured in a linear fashion from apex to crown. Statistical analysis indicated that lateral condensation and E&Q Master techniques showed lower leakage than Tagger's technique (P = 0.0016). However, statistically no difference was found between lateral condensation and E&Q Master system techniques.

The quality of single cone and laterally compacted gutta-percha fillings in small and curved root canals as evidenced by bidirectional radiographs and fluid transport measurements

OBJECTIVE

The aim of this study was to examine the quality of root fillings in small and curved root canals using bidirectional radiographs and fluid transport (FT) measurements.

STUDY DESIGN

Root canals in eighty 38 degrees -curved mesial roots of mandibular molars were prepared using a balanced force technique. Samples were divided into 4 groups of 20 each and obturated by either the cold lateral compaction (LC) or the single cone (SC) technique, using either epoxy resin-based or zinc oxide-eugenol sealers. Bidirectional (buccolingual and mesiodistal) radiographs were acquired from each root. The voids along the root filling were assessed. The FT along the root filling was measured using an FT monitoring device. The differences between the groups regarding FT and the bidirectional radiographic score were analyzed by means of a Kruskal-Wallis test. The correlation between the FT values and the radiographic scores were analyzed using a Spearman test.

RESULTS

Three groups of LC or SC fillings containing epoxy resin-based sealers exhibited similar radiographic scores and FT values (P > .05). The group of SC fillings that contained zinc oxide-eugenol sealer had worse radiographic scores than the other groups (P = .047). The bidirectional radiographic scores and the FT values for the 80 filled roots were strongly correlated (r(2) = 0.519; P = .00001).

CONCLUSION

Root fillings of similar quality were confirmed in small and curved root canals filled using either a single cone or laterally compacted gutta-percha and epoxy resin-based sealers.

The effects of canal preparation and filling on the incidence of dentinal defects

AIM

To evaluate ex vivo the incidence of defects in root dentine before and after root canal preparation and filling.

METHODOLOGY

Eighty extracted mandibular premolars were divided equally in four groups. Group 1 was left unprepared. All other root canals were prepared using Gates Glidden drills and System GT files up to size-40, 0.06 taper at the working length. Group 2 was not filled while the canals of the other groups were filled with gutta-percha and AH26, either with a master cone and passive insertion of secondary gutta percha points (group 3) or lateral compaction (group 4). Roots were then sectioned horizontally 3, 6, and 9 mm from the apex and observed under a microscope. The presence of dentinal defects (fractures, craze lines or incomplete cracks) was noted and the differences between the groups were analysed with the Fisher's exact test.

RESULTS

No defects were observed in the roots with unprepared canals. The overall difference between the groups was significant (P < 0.05). Canal preparation alone created significantly more defects than unprepared canals (P < 0.05). The total number of defects after lateral compaction was significantly larger than after noncompaction canal filling.

CONCLUSION

Root canal preparation and filling of extracted teeth created dentine defects such as fractures, craze lines and incomplete cracks.

A quantitative evaluation of sealing ability of 4 obturation techniques by using a glucose leakage test

OBJECTIVE

The aim of this study was to evaluate the sealing ability of 4 different obturation techniques by using a glucose leakage test.

STUDY DESIGN

Eighty extracted single-rooted maxillary incisors were selected for the study. The teeth were decoronated and the root canals prepared using ProFile rotary instruments to an apical dimension of size 40 (0.06 taper). The specimens were then randomly divided into 4 experimental groups (n = 15) and filled with gutta-percha and sealer by using either cold lateral compaction, warm vertical compaction, Thermafil, or the E & Q Plus system. Another 10 teeth each served as the positive and negative controls. A glucose leakage model was used for quantitative evaluation of the coronal-to-apical microleakage at 24 hours, 1, 2, 3, 5, 8, and 12 weeks.

RESULTS

No significant difference in the cumulative amount of leakage was found among the 4 groups at 24 hours and 1 week (Kruskal-Wallis test, P > .05). Lateral compaction showed significantly more leakage than the other 3 techniques at longer intervals (Mann-Whitney U test, P < .008). No significant difference was found between vertical compaction, Thermafil, and E & Q Plus at all observation times.

CONCLUSIONS

Warm vertical compaction, Thermafil, and the E & Q Plus system showed a better sealing result than cold lateral compaction of gutta-percha at extended observation periods. The glucose leakage method used in this study was able to provide a nondestructive, quantitative, and long-term evaluation of the sealing ability of root canal fillings.

Coronal sealing ability of three sectional obturation techniques ? SimpliFill, Thermafil and warm vertical compaction ? compared with cold lateral condensation and post space preparation

The purpose of this study was to evaluate the effect post space preparation has on the coronal seal of root canals obturated with cold lateral condensation of gutta-percha compared with the corsonal sealing ability of three sectional obturation techniques not requiring post space preparation. Sixty-eight human maxillary central incisors were divided equally into four groups: cold lateral condensation (Group I), SimpliFill (Group II), Thermafil (Group III) and warm vertical compaction (Group IV). After coronal flaring, all four groups were cleaned and shaped with Lightspeed rotary instruments to a size 60 master apical rotary. After obturation Peeso Reamers were used to create a post space for Group I, while Groups 2, 3 and 4 incorporated the post space in the obturation (sectional technique) and did not require making a post space after obturation. The teeth were then stored in 100% humidity for 1 week and then kept in rhodamine B fluorescent dye for 3 weeks. The teeth were then split open, and the linear dye penetration from a coronal to apical direction (coronal seal) was evaluated with a fluorescent light microscope. Statistical analysis showed that Group I (cold lateral condensation followed by post space made with Peeso Reamers) leaked significantly more (P < 0.05) than the remaining three sectional obturation groups. It was concluded that stresses generated during post space preparation might be detrimental to the seal obtained by the obturation. Sectional obturations with their superior sealing ability offer a viable alternative.

Influence of moisture on the apical seal of root canal fillings with five different types of sealer

The aim of this study was to evaluate the influence of moisture on apical leakage using five different types of sealer. There were 120 single-rooted teeth instrumented to .02/#60 and randomly assigned to 10 experimental groups, one control group (AH Plus, lateral condensation) (n = 10) or positive/negative controls (n = 5). Before obturation teeth were dried thoroughly, followed by recontamination with moisture in a wet chamber (moist groups; 37 degrees C for 7 days). The teeth of the experimental groups (a, dry; b, moist) were obturated with sealer (groups 1, AH Plus; 2, Apexit; 3, Ketac-Endo; 4, RoekoSeal; 5, Tubli-Seal) and a single gutta-percha cone .02/#55. Teeth were centrifuged (30 x g for 3 minutes) in 5% methylene blue. Linear dye penetration was measured under a stereomicroscope. Moisture led to less microleakage for Apexit, RoekoSeal, and Tubli-Seal and higher values for AH Plus and Ketac-Endo. Multifactorial ANOVA displayed a significant dependence of leakage on sealer (p < 0.001) and the combination sealer or moisture (p < 0.01). It depends on the sealer type in which way moisture affects the apical seal.

Sealing ability of three materials in the orifice of root canal systems obturated with gutta-percha

There were 130 single roots randomly assigned to one of 12 experimental or two control groups. Forty specimens each were sealed with 1, 2, 3, or 4 mm of Cavit, ProRoot MTA, or Tetric. After creation of a uniform orifice diameter, the smear layer was removed and the canal systems obturated using warm lateral compaction of gutta-percha (GP). GP was removed to the experimental depth, experimental materials placed in the orifice, and roots submerged in India ink in a vacuum flask. Specimens were demineralized and leakage measured using a 10x stereomicroscope and graded for depth of leakage by one calibrated, blinded rater. There was no significant interaction (p > 0.05) between test materials and orifice depths, nor main effect of orifice depth (p > 0.05). However, there was a statistically significant main effect of test materials with Tetric demonstrating a significantly better seal than Pro Root or Cavit (p < 0.0001) irrespective of orifice depth.

A 1-year follow-up study on leakage of single-cone fillings with RoekoRSA sealer

OBJECTIVE

The aim of this study was to measure long-term leakage along single cone (SC) fillings.

STUDY DESIGN

Two groups of canines (n = 30) were prepared and a size 55 file was the apical master file. Step-back was performed using files of sizes 60, 70, and 80. The canals were filled by the single cone technique using RoekoRSA as sealer. To place sealer into each canal, a bidirectional spiral was used in 1 group, whereas a gutta-percha cone was used in the other group. Immediately after root filling, the coronal portion of root filling was removed by postspace preparation. Leakage along the 4 mm remaining apical root filling was measured after 1 week and again after 1 year using a fluid transport model. Ten additional canine roots were prepared and filled with gutta-percha cones without sealer, serving as positive controls. Occurrence of apical extrusion of materials was recorded.

RESULTS

The apical root filling in all 60 canine roots did not show leakage either at 1 week or at 1 year. All 10 positive controls showed gross leakage (>20 muL/h). In no case gutta-percha extruded through the apical foramen. Sealer extruded apically in 88% of the roots where a gutta-percha cone was used to introduce sealer, whereas in 28% of the roots where a bidirectional spiral was used to introduce sealer (by chi-square test, P < .05).

CONCLUSION

In wide and straight canals, SC fillings with RoekoRSA sealer prevented fluid transport for 1 year. Using bidirectional spiral to place sealer reduced sealer extrusion under the conditions of this experiment.

Apical Leakage of Resin Based Root Canal Sealers with a New Computerized Fluid Filtration Meter

In this in vitro study, the apical leakage of three root-canal sealers: AH Plus, Diaket, and EndoREZ was evaluated using a new computerized fluid filtration meter. Forty-five extracted human premolar teeth with single root and canal were used. The coronal part of each tooth was removed and the root canals were prepared using GT Rotary files and crown-down technique. The roots were randomly divided into three groups of 15 samples, filled with one of the test materials and gutta-percha cones by the cold lateral condensation technique and were stored at 37 degrees C and 100% humidity for 7 days. One-week later, apical parts of roots of 10 +/- 0.05 mm were attached to computerized fluid filtration meter. Apical leakage quantity was determined as microl/cmH(2)O/min(-1). Statistical analysis indicated that root fillings with Diaket in combination with cold lateral condensation technique showed lower apical leakage than the others (p < 0.05). In addition, this new computerized fluid filtration meter allowed quantitative measurement of leakage easily. As it is a newly developed device to measure apical leakage of endodontic sealers, the reliability of it needed to be tested.

Comparison Of The Root-end Sealing Ability Of MTA And Portland Cement

The aim of this study was to compare the in vitro sealing ability of ProRoot MTA, ProRoot MTA (Tooth-Coloured Formula), ordinary Portland cement and white Portland cement when used as root-end filling materials. Twenty-four single-rooted human premolars were prepared and obturated using standard techniques, then retrofilled with the test materials. The prepared teeth were immersed in 1% methylene blue dye for 72 hours and then assessed for dye leakage. The depth of dye penetration was measured and expressed as a percentage of the length of the retrofilling. Data was analysed using ANOVA and Fisher's Least Significant Test (LSD) (p < 0.05). None of the teeth in any of the test groups showed leakage beyond the retrofillings. Given the low cost and apparently similar sealing ability of the cements, it is reasonable to consider Portland cement as a possible substitute for MTA as a root-end filling material. However, further tests, especially in vivo biocompatibility tests, need to be conducted before Portland cement can be recommended for clinical use.

Effect of different rotary instrumentation techniques and thermoplastic filling on apical sealing

The aim of this study was to evaluate apical sealing after root canal treatment using two different rotary instrumentation techniques and two thermoplastic root canal filling techniques. The study was performed in 115 human extracted mandibular premolars. After coronary access the apical foramen was opened with a # 15 K file 1 mm beyond the apex. Cleaning and shaping was subsequently carried out at the working length, 1 mm from the apex, with ProFile .04/.06 system (Dentsply/Maillefer), Quantec (Analytic Endodontics/Kerr) or by the step-back technique with 1% sodium hypochlorite solution as irrigating solution. The root canals were filled with Thermafil (Dentsply/Maillefer) or Microseal (Analytic Endodontics/Kerr) or by lateral condensation technique using AH Plus sealer (epoxy type). The teeth were immersed in 2% methylene blue under vacuum. Then, they were longitudinally sectioned. The results showed that the association of Profile and Thermafil Plus provide the best results (p<0.05). In conclusion, the association of different rotary instrumentation techniques and different filling systems influenced the apical sealing.

Effects of calcium hydroxide paste medication on coronal leakage

The purpose of this in vitro study was to examine the coronal leakage of canals medicated with Ca(OH)(2) compared with the canals which did not receive Ca(OH)(2) medication before obturation with laterally condensed gutta-percha points and sealer. Sixty-one single rooted permanent canines and premolars were used. The crowns were removed from the cemento-enamel junction. After the canals were chemomechanically prepared, the roots were divided into three experimental groups as group 1, 2 and 3. The canals in group 1 and 2 were treated with ethylenediaminetetraacetic acid (EDTA) and NaOCl in order to remove the smear layer and then the canals were filled with Ca(OH)(2) paste. The coronal 3 mm of the cavities were sealed with Cavit and the samples were kept in an incubator at 37 degrees C for 7 days. No intra-canal medication was applied in group 3. The root canals were irrigated with NaOCl in group 1 and with EDTA and NaOCl in group 2, in order to remove Ca(OH)(2) before obturation. Two samples from group 1 and two from group 2 were examined under SEM in order to reveal the removal of Ca(OH)(2) paste. Following this, the canals in the experimental groups were obturated with gutta-percha and sealer. The roots were placed in India ink for 7 days and the linear dye penetration was evaluated. No significant statistical difference was found in the amount of coronal dye leakage between experimental groups (P > 0.05). The results of the present study indicated that the application of Ca(OH)(2) as a temporary dressing material had no effect on coronal leakage.

Fluid transport along gutta-percha backfills with and without sealer

OBJECTIVE

The use of heat may influence the sealing ability of sealer. The aim of this study was to compare the fluid transport along the gutta-percha backfill portion when different sealers were used or no sealer at all.

STUDY DESIGN

Four groups consisting of the roots of maxillary and mandibular canines were instrumented and obturated with vertically compacted warm gutta-percha. Down-pack was carried out using Touch 'n Heat (Analytic Technology, Redmond, Wash, USA) and prefitted pluggers. Back filling was achieved by injecting warm gutta-percha using Obtura II (Obtura Corporation, Fenton, Mo). In the first 3 groups, 1 of 3 sealers was used: RoekoSeal Automix (RSA), Pulp Canal Sealer EWT (EWT), and AH26. In the fourth group no sealer was used. The apical root filling was removed, and fluid transport along the backfill portion was measured using a fluid transport device.

RESULTS

A statistically significant difference in fluid transport was found among the 4 groups (P = .038). The no-sealer group recorded the highest fluid transport. The AH26 group was the only sealer group that displayed significantly less fluid transport than the no-sealer group (P = .006). The AH26 displayed less fluid transport than the EWT group (P = .017).

CONCLUSION

The backfills with AH26 as sealer provided a better seal than the backfills of injected warm gutta-percha with EWT as sealer or with no sealer at all.

Intracanal Distribution Patterns of Sealers After Lateral Condensation

The purpose of this study was to examine coverage patterns of sealer on canal walls and between gutta-percha cones after lateral condensation. Ninety extracted teeth with single canals were evenly and randomly divided into three sealer groups (Roth's, Sealapex, AH 26). Canals were cleaned and shaped, then coated with one of the three sealers followed by lateral condensation of gutta-percha. The teeth were placed into 100% humidity at 37 degrees C. After 4 months the roots were notched and fractured longitudinally and the dentin lifted to expose the gutta-percha sealer and dentin walls. Qualitative assessment was in the apical and coronal as to the amount and the pattern of sealer coverage. Coverage was categorized by the amount and location as follows: (a) no sealer; (b) slight-partial; (c) moderate-partial; or (d) complete coverage. Sealer was frequently absent between gutta-percha cones and the canal wall and at times absent between cones, with a general moderate-partial coverage. No sealer group demonstrated complete coverage; however, AH 26 showed more consistent moderate-partial distribution. Coverage was better in the coronal. In conclusion, none of the three sealers showed a continuous layer between the primary gutta-percha obturant and the canal wall or in spaces between cones.

The effect of using an inverted master cone in a lateral compaction technique on the density of the gutta-percha fill

OBJECTIVE

We sought to measure and calculate the percentage of the gutta-percha-filled area in the apical root canal after the use of a standardized or inverted master cone in cold lateral compaction.Study design Two groups of extracted mandibular premolars with a single canal were instrumented with instruments of the same size; furthermore, they were obturated with laterally compacted gutta-percha cones with AH26 used as a sealer. In the first group, a standardized master cone was used with its narrow end in an apical position, whereas in the other group, an inverted master cone was used with its wide end in an apical position. The 2 master cones had the same apical diameter and fit in the apical canal. After lateral compaction, horizontal sections were cut at a level 3 and 5 mm from the apex of each filled tooth. Photographs of the sections were taken by using a microscope equipped with a digital camera; the photos were then scanned as tagged-image file format images. The cross-sectional area of the canal and the gutta-percha were measured by using an image-analysis program. The percentage of gutta-percha-filled area was calculated.

RESULTS

At both levels, the inverted master cone produced a significantly higher percentage, statistically, of gutta-percha-filled area than did the standardized master cone (P =.001 at 3 mm; P =.012 at 5 mm).

CONCLUSION

The use of an inverted master cone in cold lateral compaction may facilitate the apical placement of accessory cones, significantly increasing the volume of gutta-percha while reducing the volume of sealer in the apical root canal.

Fluid movement along the coronal two-thirds of root fillings placed by three different gutta-percha techniques

AIM

To compare fluid movement (FM) along the coronal two-thirds of gutta percha/sealer root fillings placed by three different techniques.

METHODOLOGY

Three groups consisting of the roots of mandibular incisors were instrumented and obturated by cold lateral compaction (LC), warm vertical compaction (VC) or the single-cone technique (SC), using RoekoSeal Automix (RSA) as the sealer. The apical 4 mm of each root filling was removed, and FM along the remaining 7 mm of the root filling was measured.

RESULTS

The VC group displayed more FM than the other two groups (P = 0.023). No significant difference in FM was found between the LC and SC groups (P = 0.629).

CONCLUSIONS

The coronal two-thirds of the VC root fillings did not prevent FM when RSA sealer was used.

A comparative study of lateral condensation, heat-softened gutta-percha, and a modified master cone heat-softened backfilling technique

AIM

The aim of the study was to compare the quality of root fillings completed by lateral condensation (L), Thermafil (TF), and a new technique using Thermafil for backfilling (BF), with special emphasis on control of overfilling.

METHODOLOGY

Sixty curved canals in plastic blocks were prepared with the ProFile system to size 40/04 taper in the apical half and to 06 taper in the coronal half. The canals were divided into three groups of 20. Apical patency was verified with a size 15 K-file. The canals were then filled using three different techniques: LC (20 canals), TF (20 canals), and BF, where a size 40 master point with sealer was seated prior to the introduction of a size 30 Thermafil point (20 canals). The same resin-based sealer was used on each occasion. The root fillings were assessed using stereo-microscopy for material extrusion, digital radiography for occurrence of voids, and microscopy of sections for voids and thickness of sealer layer.

RESULTS

Extrusion of both gutta-percha and sealer occurred in all 20 canals filled with the TF technique, but only three and five cases of sealer extrusion were detected with LC and BF techniques, respectively. No voids were detected in the TF group, whereas small voids were present in most fillings in the LC and BF groups. The average total length of the voids was less than 1 mm per canal. The thickness of the sealer layer in the middle and apical parts was greater in the LC and BF groups than in the TF group.

CONCLUSIONS

LC and BF techniques resulted in fewer overfills than TF. Voids were absent in TF fillings, whilst small voids were found in the LC and BF groups.

The long-term sealing ability of an epoxy resin root canal sealer used with five gutta percha obturation techniques

AIM

The aim of the present study was to evaluate the long-term sealing ability (both apical and coronal) of an epoxy resin root canal sealer (AH26) when used with different gutta-percha obturation techniques.

METHODOLOGY

Straight single-rooted teeth with mature apices were divided into 10 groups of 75 teeth and one group of 40 control teeth. Root canals were prepared according to the crown-down/step-back technique and using both 2.5% sodium hypochlorite and an EDTA paste. Root canals were obturated using cold lateral condensation, warm vertical condensation and hybrid condensation of gutta-percha; and with Thermafil and Soft-Core obturators. AH26 was used as the sealer in all cases. After root canal filling, each group was divided into five individual groups of 15 teeth. The first group of 15 teeth was kept for 1 day, the second for 1 week, the third for 4 months, the fourth for 6 months and the fifth for 12 months at 37 degrees C in vacutainers in 80% relative humidity. The teeth were immersed in India ink for 90 h, each root was split and sectioned longitudinally, and the maximum extent of leakage was measured using a stereomicroscope at x6 magnification.

RESULTS

Leakage occurred whatever filling technique was combined with AH26. The number of teeth with gross leakage increased with time up to 4 months, but did not appear to increase between 6 and 12 months storage. The degree of apical leakage and the number of leaking teeth in the Soft-Core obturator groups was significantly higher than all four other gutta-percha obturation techniques. Up to 4 months the degree of coronal leakage and the number of leaking teeth in the Thermafil groups was significantly higher than the other gutta-percha obturation techniques, except for Soft-Core. In the Soft-Core obturator groups the degree of coronal leakage and the number of leaking teeth was significantly higher than the other gutta-percha obturation techniques, except for Thermafil at all evaluation times.

CONCLUSION

The hybrid gutta-percha condensation technique was superior to the other four obturation techniques in respect of apical leakage. Coronal leakage was significantly greater during the first 4 months for the Thermafil system as compared to the three condensation techniques; coronal leakage was significantly greater at all time periods for the Soft-Core system. There were no significant differences between the Thermafil and the Soft-core system.

Apical leakage of obturated canals prepared by Er:YAG laser

The present study evaluates the degree of apical leakage in vitro after root canal preparation using Er:YAG laser irradiation followed by obturation. Twenty-four single-rooted teeth were divided into 2 groups of 12. One group served as a control and these root canals were conventionally prepared up to a #50K file. The other group was prepared by Er:YAG laser irradiation at parameters of 2 Hz and 170 to 230 mJ/pulse. After obturation the teeth were immersed in a vacuum flask containing 0.6% rhodamine for 48 h, longitudinally bisected, and observed by stereoscopy and scanning electron microscopy. The degree of apical leakage from an apical stop was measured and statistical analysis was performed. The degree of apical leakage from the teeth prepared by laser was not significantly less than that from control teeth (p > 0.01). Morphological findings showed that contact between the root canal walls and obturated materials was hermetic in both groups, but canal walls prepared by laser were rough and irregular. These results show that root canal preparation by laser does not affect apical leakage after obturation compared with leakage in canals prepared using the conventional method.

An in vitro experiment on the effect of an attempt to create an apical matrix during root canal preparation on coronal leakage and material extrusion

OBJECTIVE

A common approach to creating an apical matrix (apical stop) in the apical dentin is to enlarge the root canal to 3 sizes greater than that of the first file that binds at the working length. The aim of this study was to test the hypothesis that this procedure will reduce the amount of material extruded and the leakage along the apical root fillings.

STUDY DESIGN

The canals of half of 120 maxillary and mandibular canines were prepared to the apical foramen through use of the serial shaping technique; the apical matrix creation procedure was not used. Each of the other 60 canals was prepared to 1 mm short of the apical foramen, and the canal was enlarged to at least 3 sizes greater than that of the first binding file to create an apical matrix. All the canals prepared with and all the canals prepared without the apical matrix creation procedure were obturated with laterally or vertically compacted cold or warm gutta-percha. In the leakage test, after post space preparation, the amount of fluid transport along the apical root fillings was measured. In the material extrusion test, the number of teeth with gutta-percha extrusion was recorded and the weight of the apically extruded materials was measured.

RESULTS

In both the leakage and the extrusion tests, no significant difference was found between canals prepared with and canals prepared without the apical matrix creation procedure.

CONCLUSION

The hypothesis that a procedure to enlarge root canals to 3 sizes greater than that of the first binding file will reduce the amount of filling materials extruded and the leakage was not proved, as our results show.

Sealer distribution in root canals obturated by three techniques

AIM

The aim of this study was to observe sealer distribution in root canals filled by different root filling techniques.

METHODOLOGY

AH26 (0.05 mL) dyed with carbon black powder was placed into the prepared root canals of maxillary central incisors using a lentulo spiral. Thereafter the canals were obturated using three different gutta-percha root-filling techniques. Horizontal sections were cut in the apical and middle portions of the filled canals. Images of the cross sections were scanned and the percentage of sealer coated canal perimeter (PSCP) was measured using a computer digital imaging system.

RESULTS

At 3 mm from the apex, the PSCP after lateral condensation was similar to that after vertical condensation (P > 0.05). At 6 mm from the apex, however, the PSCP was significantly higher after lateral condensation than after vertical condensation (P < 0.05). At both levels the PSCP was significantly higher after single cone (no condensation) than after the other two condensation techniques (P < 0.0001).

CONCLUSIONS

Sealer may be removed from the canal wall by the condensation procedures.

A comparative study of apical leakage of Apexit, Ketac-Endo, and Diaket root canal sealers

The purpose of this study was to compare the apical leakage of Ketac-Endo, Apexit, and Diaket. Fifty freshly extracted human maxillary anterior teeth were used. The anatomical crowns were removed at the amelocemental junction, and step-back preparation of the roots canals was performed with K-type files to size 40 using 2 ml of 5.25% NaOCl irrigant after each file change. The roots were randomly divided into five groups of 10 roots each: three experimental and two control groups. The experimental groups were as follows: group 1, Apexit; group 2, Ketac-Endo; and group 3, Diaket. Root canals were filled with one of the sealers and gutta-percha using lateral condensation. After the specimens were stored in 100% humidity at 37 degrees C for 2 wk, the roots were covered with two layers of nail polish and immersed in 2% methylene blue for 7 days. Each tooth was split into two sections, and dye penetration was evaluated independently by three examiners using a stereomicroscope at x20 magnification. Mann-Whitney U analysis showed that there was no significant difference between Apexit and Diaket (p > 0.05). However, there was significantly more leakage with Ketac-Endo (p < 0.05).

Leakage of five root canal sealers

AIM

The aim of this study was to examine the apical sealing ability of five root canal sealers using a fluid transport model.

METHODOLOGY

A comparison of root canal scalers AH26, AH Plus, Diaket, Apexit, and Ketac-Endo were tested on 60 single-rooted teeth. The coronal part of each tooth was removed at the amelo-cemento junction, and also 3 mm of the root tip. Root canals were instrumented using the 'step-back' technique with Gates Glidden drills and irrigated with 2.5% NaOCl. The specimens were divided into five groups of 10 samples each and filled with test materials and gutta-percha points by the cold lateral condensation technique. Ten teeth were used as a control group, out of which five served as negative and five as positive controls. The leakage was measured by the movement of an air bubble in a capillary glass tube connected to the experimental root section.

RESULTS

The differences in leakage amongst Ketac-Endo (0.318 microL: SD 0.084), AH26 (0.319 microL; SD 0.075), AH Plus (0.330L; SD 0.085) Apexit (0.360 microL; SD 0.127) and Diaket (0.387 microL; SD 0.140) were not statistically significant (P > 0.05).

CONCLUSIONS

Under the conditions of this study, all five sealers produced a satisfactory seal.

Comparison of two vertical condensation obturation techniques: Touch 'n Heat modified and System B

AIM

The aims of this study were firstly to compare the area of canal occupied by gutta-percha, sealer or voids using the System B heating device with that obtained by a modified vertical condensation technique using the Touch 'n Heat: and secondly to compare the temperature changes at the root canal wall and external root surface during obturation with the above techniques.

METHODOLOGY

Forty-five resin blocks, each with a standardized, simulated, prepared main root canal and five lateral canals, were assigned to three equal experimental groups. The canals were obturated using either the System B technique at two different temperature settings, or vertical condensation with a Touch 'n Heat instrument as the heat source. A heat transfer model was used to simultaneously record internal and external root surface temperature elevations during obturation by the three techniques. Data were analysed using unpaired Student's t-test and Mann-Whitney U-test.

RESULTS

Both obturation techniques produced root fillings consisting of over 90% gutta-percha at most levels, although the percentages of sealer and voids 2-3 mm from the working length following System B obturation were higher than those found following modified vertical condensation. Modified vertical condensation resulted in more gutta-percha in lateral canals. Obturation was accomplished more quickly using the System B, and temperature elevations produced during obturation with the System B were significantly less (P < 0.001) than with vertical condensation. An elevation of external root surface temperature by more than 10 degrees C occurred during vertical condensation.

CONCLUSIONS

The results suggest that the System B may produce an acceptable obturation and that the use of a Touch 'n Heat source during vertical condensation may result in damage to the periodontium.

Effect of masticatory cycles on apical leakage of obturated teeth

This study investigated the effect of apical leakage due to masticatory cycles on root canal treatment. Twenty upper maxillary molars were first obturated using the warm vertical compaction technique. Four maxillary casts were then built, with each holding four of the sample molars. The molars were embedded in resin with the roots separated from the resin by means of a light silicon. The four remaining teeth served as controls and were not submitted to occlusal forces. A mechanical device to simulate masticatory cycles subjected the teeth to 0.5 x 10(6) cycles (group A), 10(6) cycles (group B), 2 x 10(6) cycles (group C), and 3 x 10(6) cycles (group D); the control was group E. The roots were placed in 2% methylene blue dye solution for 72 h and then sectioned longitudinally so that dye penetration could be measured. The mean values of dye penetration were: 3.70 +/- 0.69 mm, group A; 5.00 +/- 1.14 mm, group B; 6.00 +/- 1.01 mm, group C; 7.23 +/- 0.66 mm, group D; and 2.74 +/- 0.75 mm, group E. The value of dye penetration increased in correlation with the number of masticatory cycles. This in vitro study suggests the significant effect of masticatory loads on apical leakage.

Apical leakage of a new glass ionomer root canal sealer

A new glass ionomer root canal sealer (Ketac-Endo) has been developed. The purpose of this study was to compare the apical leakage of Ketac-Endo and AH26 using two different filling techniques and a controlled vacuum procedure. Sixty-four extracted human maxillary anterior teeth were instrumented and divided into four groups of 15 roots each. The groups were obturated as follows: group 1, a single cone technique and Ketac-Endo; group 2, a lateral condensation technique and Ketac-Endo; group 3, a single cone technique and AH26; and group 4, a lateral condensation technique and AH26. After storage in 100% humidity at 37 degrees C for 1 wk, the root surfaces were coated with two layers of nail polish and sticky wax. All specimens were immersed in a vacuum flask containing 2% methylene blue dye solution. The air was evacuated with a vacuum pump. The roots were sectioned longitudinally, and the linear extent of dye penetration was measured. Statistical analysis revealed that there were no significant differences between any of the groups.

An in-vitro evaluation of sealer placement methods

Successful root canal therapy is dependent upon obturating the root canal system. A critical component of the filling procedure is sealer placement. This in vitro study investigated the efficacy of six methods of sealer placement using clear plastic blocks with simulated curved canals instrumented to the apex using a step-back technique. After sealer placement and setting, the blocks were cross-sectioned at 2 mm intervals from mid-canal to apex. The sections were evaluated with a stereo operating microscope at x6 magnification for placement of an evenly distributed layer of sealer around the prepared canal walls. The lentulo spiral and the Max-i-Probe Delivery System were the most effective means of sealer placement, followed by ultrasonic and sonic files. The least effective methods were the paper point and the K file.

Effect of reduced air pressure on dye penetration in standardized voids

OBJECTIVE

This study determined the correlation between the degree of dye penetration in standardized voids to various reduced pressures.

STUDY DESIGN

Standardized voids of 0.50 and 0.22 mm in diameter were created in 60 human roots; specimens were divided into five groups. Four groups were subjected to a 2% filtered aqueous methylene blue dye solution under different conditions of atmospheric pressure for 7 days and reduced pressures of a 10 torr, a 260 torr, and a 510 torr for 30 minutes. The conditions for the fifth group were similar to the last group except that ethyl alcohol was substituted for water in the dye.

RESULTS

All positive control specimens showed complete dye penetration. The least linear dye penetration was observed in passively immersed specimens. The results were significantly different from those when reduced pressure had been used (p < 0.001). There were no significant differences among the groups with reduced pressure. No significant difference was found at any pressure level between the means of dye diffusion in the 0.50 and the 0.22 mm voids. The smallest standard deviations were observed for the most reduced air pressure of 10 torr, followed by the group of the least reduced pressure of 510 torr, with the use of the tincture dye solution.

CONCLUSIONS

A 10-torr reduced pressure and an application of the tincture dye solution would provide an improved method for microleakage studies.