Journal of the International Clinical Dental Research Organization

ORIGINAL RESEARCH
Year
: 2015  |  Volume : 7  |  Issue : 1  |  Page : 30--34

An in vitro comparision of apical leakage in immediate versus delayed post space preparation using EndoREZ and RoekoSeal root canal sealers


Munniswamy Kala, Sourabh Jagannath Torvi 
 Department of Conservative Dentistry and Endodontics, Government Dental College and Research Institute, Bangalore, Karnataka, India

Correspondence Address:
Dr. Sourabh Jagannath Torvi
No. 122, 3 B Cross,6 A Main Road, 7th block, 2nd Stage, Nagarbhavi, Bangalore - 560 072, Karnataka
India

Abstract

Context: The newer resin and silicone-based sealers have a shorter setting time when compared to conventional zinc oxide-based sealers. This factor may influence the effect of the timing of post space preparation on the integrity of remaining apical root canal filling. Aims: The purpose of this study was to evaluate the apical dye leakage of samples obturated with EndoREZ and RoekoSeal root canal sealers with reference to the timing (immediate and delayed) of post space preparation. Settings and Design: An in vitro study using extracted human teeth as study samples and the method of apical dye penetration to determine the apical micro-leakage microscopically. Materials and Methods: Seventy single-rooted anterior extracted teeth were instrumented and divided into ix groups; fifteen teeth in groups 1, 2, 3, and 4 and five teeth in groups 5 and 6. In groups 1 and 2, specimens were obturated with warm vertical compaction and EndoREZ sealer. In groups 3 and 4, specimens were obturated with warm vertical compaction and RoekoSeal sealer. Immediate post space was prepared in groups 1 and 3. The samples in groups 2 and 4, the post space was prepared after placing the teeth in saline at 37°C for 1 week. Groups 5 and 6 represented positive and negative controls, respectively. The samples were then placed in methylene blue for 72 hours. The samples were then sectioned longitudinally and the amount of linear apical dye migration was evaluated. Statistical Analysis Used: One-way analysis of variance (ANOVA) and multiple pair-wise comparisions using Tukeys multiple post hoc procedures. Results: There was a statistically significant difference in the mean apical dye micro-leakage values in between the EndoREZ and RoekoSeal groups, i. e., groups 1, 2 and groups 3, 4. Conclusions: EndoREZ root canal sealer groups exhibited a higher mean apical dye micro-leakage value as compared to the RoekoSeal root canal sealer groups. Immediate post space preparation resulted in a relatively lower mean apical dye micro-leakage as compared to delayed post space preparation, but the difference was not statistically significant.



How to cite this article:
Kala M, Torvi SJ. An in vitro comparision of apical leakage in immediate versus delayed post space preparation using EndoREZ and RoekoSeal root canal sealers.J Int Clin Dent Res Organ 2015;7:30-34


How to cite this URL:
Kala M, Torvi SJ. An in vitro comparision of apical leakage in immediate versus delayed post space preparation using EndoREZ and RoekoSeal root canal sealers. J Int Clin Dent Res Organ [serial online] 2015 [cited 2020 May 28 ];7:30-34
Available from: http://www.jicdro.org/text.asp?2015/7/1/30/153492


Full Text

 INTRODUCTION



One of the aims of endodontic treatment is to obturate the root canal system with an impervious, biocompatible, and dimensionally stable filling material. Obturation with guttapercha cones and sealer are now accepted as the most reliable method for filling the root canal system. A perfect apical seal will exclude the entry of micro-organisms or leakage of tissue fluids into the canal space, thereby contributing to the success rate of the endodontic treatment.

The materials used for root canal obturation must possess several different properties relative to their functions and location, ranging from biocompatibility to mechanical sealing ability. [1] Selection of the type of post endodontic restoration is crucial and is more complicated when the remaining tooth structure is highly compromised. The post and core system, followed by a crown is an efficient method of restoring such endodontically treated teeth, as they help in retention of coronal restoration and distribute the functional stresses along the root dentin.

Several studies have shown varying results on the effect of timing of post space preparation following obturation, on the apical leakage [2],[3],[4]

Immediate post space preparation has advantages since it has been claimed that the entire procedure is done in the same visit using rubber dam isolation. The condensation of the remaining guttapercha can be assessed; if necessary, some modifications can be done. Newer materials and obturation methods in the field of endodontics have made success predictable and definite. Resin materials have gained popularity and are now accepted as root canal filling materials.

The newer resin and silicone-based sealers have a shorter setting time when compared to conventional zinc oxide-based sealers. This factor may influence the effect of the timing of post space preparation on the integrity of remaining apical root canal filling. The purpose of this study was to compare urethanedimethacrylate (UDMA)-based EndoREZ and Siloxane-based RoekoSeal sealers with reference to post space preparation timings - immediate and delayed; on the sealing effectiveness at the remaining apical root canal filling.

 Materials and Methods



All procedures in this study have been performed in compliance with the relevant laws and institutional guidelines; this study has been approved by the ethical committee of the institution. Informed consent was obtained prior to extraction of the teeth being used for this study from the patients. Seventy extracted human single-rooted teeth with straight roots and closed apices were randomly selected and checked for absence of root caries, cracks, and structural defects. The crown of each tooth was removed at the cementoenamel junction, and the roots were stored in buffered 10% formalin solution until use. The canal patency was determined with by passing no. 10 k-file into the root canal until the tip of the file was visible at the apical foramen. Working lengths were established by subtracting 1 mm from the measurement obtained when a size 10 file was placed into the canal until its tip was visible under stereomicroscope at the root apex of the study specimens. Bio-mechanical preparation was carried out using the K3 # 30, 0.06% files with copious irrigation of 1 ml of 3% sodium hypochlorite and 17% ethylenediaminetetraacetic acid (EDTA). Final rinse prior to obturation was done with normal saline to flush any remaining irrigants from the canal. The canals were dried with sterile absorbent paper points. The teeth were then randomly divided into four experimental groups [Table 1], each containing 15 teeth each and two control groups, containing five teeth each. In groups 1 and 2, specimens were obturated with gutta-percha and EndoREZ sealer using Shilder's warm vertical condensation technique. Following the manufacturer's instructions, EndoREZ sealer was dispensed using the provided mixing tips and delivered into the root canal. In groups 4 and 5, specimens were obturated with gutta-percha and RoekoSeal sealer using Shilder's warm vertical condensation technique. Following the manufacturer's instructions the RoekoSeal sealer was dispensed using the provided "ready mix" tips and delivered into the root canal.{Table 1}

The corresponding 0.06% taper # 30 guttapercha cones were then inserted into the root canals of all the specimens of the groups with firm pressure. Buccolingual and mesiodistal radiographs were obtained to evaluate the quality of the root filling, specifically homogeneity and apical extension. The excess guttapercha extending from the coronal part of the canal was removed with a heated spoon excavator.

In the positive control group, samples were obturated with the guttapercha fit to tug back with no sealer. The negative control group consisted of samples with no obturation material and the samples were completely sealed with sticky wax and fingernail polish.

The post spaces were prepared immediately before the initial set of the sealer in groups 1 and 3 with peeso reamers from size 1 to 4 at 4,000 rpm to a depth that left 4 mm of guttapercha apically. In groups 2 and 4, the samples were stored in 0.9% saline at 37 o C for 1 week and the post spaces was prepared with peeso reamers from size 1 to 4 at 4,000 rpm to a depth that left 4 mm of guttapercha apically.

In all the experimental groups and positive control groups, the coronal orifice was then sealed with sticky wax and the entire surface of the roots except the apical 2 mm were covered with two layers of nail polish. Each coat was thoroughly dried before the subsequent one was applied. The purpose of the positive control group was to demonstrate the capability of the method to disclose voids present in the root canal filling because of the absence of a sealer. In the negative control group, the external root surface was completely covered with two layers of nail polish including the coverage of apical portion and the apical foramen. Each coat was thoroughly dried before the subsequent one was applied. The purpose of negative control group was to verify the ability of the root coverage to prevent dye penetration through the lateral root surfaces and the canal. After 1 hour when the nail varnish had completely dried, all the teeth were immersed in a solution of 2% methylene blue for 72 hours at room temperature.

The teeth were then sectioned vertically along the long axis. To ensure that the sectioning process did not damage the inside of the canal, the sectioning was done with water cooled diamond disc along the root, short of reaching the guttapercha, thereby creating a stress canal. A chisel was used to wedge and split the teeth. Samples were then evaluated under a stereomicroscope for visible coronal extent of dye penetration from the apical constriction and the higher value among them was taken. With the help of the photomicrographs obtained, the linear measurement of the dye penetration was noted from apical to coronal direction to nearest 0.1 mm at 20× magnification [Table 2] and [Figure 1] and [Figure 2].{Figure 1}{Figure 2}{Table 2}

The mean and standard deviation of micro-leakage in millimeters in all four study groups was compared using analysis of variance (ANOVA), followed by multiple comparisons using post hoc Tukey test [Table 3] and [Table 4]. A probability value of <0.05 was considered to be statistically significant.{Table 3}{Table 4}

 RESULTS



One way ANOVA for groups 1, 2, 3, and 4 showed that there was a statistically significant difference in the mean apical dye leakage between all groups. [Table 4] shows that groups 3 (RoekoSeal - immediate post space preparation) and 4 (RoekoSeal - delayed post space preparation) were statistically significant from groups 1 (EndoREZ - immediate post space preparation) and 2 (EndoREZ - delayed post space preparation). There was no statistically significant difference between groups 1 and 2 and also groups 3 and 4.

 DISCUSSION



The primary objective of successful endodontic treatment depends on adequate post endodontic restorations, to enable the pulpless teeth to function as an integral part of the masticatory apparatus. Removal of the obturating material from the root canals for post space can be done by thermal, chemical, or mechanical methods. [5],[6] Either immediately after obturation or delayed until complete setting of the sealer. [2],[3],[4] During preparation of the post space, it is important not to disrupt the integrity of the apical seal since the success of root canal therapy depends on the ability to establish and maintain a hermetic seal. Apical obturation blocks the portal of exit for micro-organisms to the periapex if these micro-organisms would have survived in the pulp cavity and the pulp space, even after instrumentation and disinfection thereby ensuring endodontic success.

EndoREZ (Ultradent Products Inc, South Jordan, UT) is a dual cure hydrophilic resin root canal sealer based on urethane dimethacrylate. EndoREZ is a root canal sealer that has a working time of 12-15 minutes and a setting time of approximately 15-20 minutes at body temperature. Its active ingredient is UDMA). EndoREZ is a hydrophilic, two component (base and catalyst), and a self-priming sealer.

The EndoREZ base contains:

Urethane dimethacrylate resin - active ingredientA bismuth compound as the radiopaque fillerSmall amounts of other fillersTriethylene glycol dimethacrylateA peroxide initiator

The EndoREZ catalyst contains:

A bismuth compound as the radiopaque fillerSmall amounts of other fillersDiurethanedimethacrylateTriethylene glycol dimethacrylate

The hydrophilic properties of the EndoREZ sealer promotes penetration of the sealer into moist dentin and dentin tubules thus substantially reducing micro-leakage. [7],[8]

RoekoSeal (Roeko, Langenau, Germany) is a highly bio-compatible polydimethylsiloxane-based root canal sealer. The working time of RoekoSeal is 15-30 minutes, curing takes place after 45-50 minutes. The use of heat shortens the working time. It has mechanical adhesion to root canal wall due to expansion on setting. Furthermore, the manufacturer claims that RoekoSeal is thixotropic, so the sealer becomes less viscous under pressure and flows into the dentinal tubules. In contrast to other sealers, RoekoSeal does not shrink but actually expands (0.2% by volume). It has mechanical bonding to the dentinal walls due to expansion, which makes it easier to remove in cases of retreatment and during post space preparation. This slight expansion also results in better sealing abilities.

Composition of RoekoSeal root canal sealer:

PolydimethylsiloxaneSilicone oilParaffinHexachloride platinum acidZirconiumdioxide

Removal of guttapercha with peeso reamer resulted in lesser disturbance of the apical seal, further the frictional heat produced by rotary instruments, plasticized the guttapercha helping in their safe removal. In addition, slight vertical pressure during the removal of guttapercha may act as vertical condensation, which might improve the apical seal. [6]

The integrity of apical seal is proportional to the amount of remaining filling material. It has been reported in studies that 4-5 millimeters of apical guttapercha should be retained apically which may provide adequate apical seal. [9],[10],[11] Other studies reported that post which was two third the length of the root was preferable. [12]

The dye penetration technique was used to evaluate theleakage in different studies. [13] We also used dyepenetration technique and stereomicroscope to evaluate theleakage of specimens. [14] It has been shown that dye penetrates voids better than isotopes and reveals micro-lumina in obturated root canal spaces in greater depth than other tracing materials. [15]

Statistically significant difference was seen in the mean apical dye micro-leakage values in between the RoekoSeal root canal sealer (group 3 and group 4) and the EndoREZ root canal sealer groups (group 1 and group 2). RoekoSeal root canal sealer groups (groups 3 and 4) exhibited lower mean apical dye micro-leakage, this may be attributed to the slight expansion (0.2% by volume) of this root canal sealer, which might promote close mechanical adaptation to the root canal dentinal walls on setting. The EndoREZ groups (group 1 and 2) exhibited higher mean apical dye micro-leakage values. This observation may be attributed to the inherent polymerization shrinkage seen with resin root canal sealers. RoekoSeal is also more dimensionally stable and less soluble as observed in studies. [16]

When mean apical dye leakage values of Immediate post space preparation (group 1 and 3) and delayed post space preparation group 2 and 4) were compared; it was observed that the immediate post space preparation (group 1 and 3) exhibited lower mean apical dye leakage values as compared to delayed post space preparation group 2 and 4). But, these differences were not statistically significant. This was in concurrence with the other studies which showed no significant difference between immediate and delayed post space preparation. [2],[3],[5],[17]

Within the limitations of this study, it can be concluded that the timing of the post space preparation, i. e., immediate (immediately after obturation) or delayed (after 7 days) did not have any significant effect on the sealing ability of the two root canal sealers used in this study. The dimethyl siloxane chemistry-based RoekoSeal root canal sealer provided a better apical seal as compared to the urethane dimethacrylate-based EndoREZ root canal sealer. Further studies using different techniques with a larger number of cases are recommended.

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