| Abstract|| |
Objective: Present in-vitro study aimed to evaluate the apical leakage of different bioceramic retrofilling materials with and without smear layer. Materials and Methods: Sixty human single-rooted teeth were decoronated at a standardized root length of 13 mm, chemo-mechanically prepared and obturated. After obturation, root-end resection was done and root-end cavities were prepared using ultrasonic tips. The specimens with prepared retro cavities were randomly assigned into 2 groups (n = 30) based on the smear layer removal protocol used. Each group was further subdivided into 3 subgroups (n = 10) based on the bioceramic retrofilling material MTA (Mineral Trioxide Aggregate; Proroot Dentsply/Tulsa), CEM (Calcium-Enriched Mixture; Bionique Dent, Tehran) and ERRM (EndoSequence® Root Repair Material; Brasseler USA, Savannah, GA). The extension of dye (2% Rhodamine B) penetration was measured in millimetre using a stereomicroscope at 10× zoom. Results were statistically analysed using one-way ANOVA (analysis of variance) test and unpaired Student's t test. Results: In the presence of smear layer, MTA demonstrated maximum mean apical leakage value (1.70 ± 0.30), followed by CEM (1.40 ± 0.37) and ERRM (1.40 ± 0.23), which was statistically not significant. Without the smear layer, ERRM demonstrated the least mean apical leakage value, which was statistically significant as compared with CEM (P <.05) and MTA (P <.01). Conclusion(s): All bioceramic retrofilling materials demonstrated apical leakage irrespective of the presence or absence of the smear layer. The presence of a smear layer is beneficial for the sealing ability of MTA and CEM, whereas, the absence of the smear layer is advocated while using ERRM.
Keywords: Apical leakage, calcium enriched mixture, endoSequence root repair material, mineral trioxide aggregate, smear layer
|How to cite this article:|
Shahbaz S, Iftekhar H, Alam S, Mishra SK. Comparative evaluation of the apical leakage of different bioceramic retrofilling materials with and without smear layer: A stereomicroscopic study. Indian J Dent Res 2022;33:46-51
|How to cite this URL:|
Shahbaz S, Iftekhar H, Alam S, Mishra SK. Comparative evaluation of the apical leakage of different bioceramic retrofilling materials with and without smear layer: A stereomicroscopic study. Indian J Dent Res [serial online] 2022 [cited 2022 Oct 4];33:46-51. Available from: https://www.ijdr.in/text.asp?2022/33/1/46/353532
| Introduction|| |
Periradicular surgery creates an optimum environment for apical tissue healing by entombing and eliminating the source of periradicular infection. It involves resection of 3 to 4 mm of root end that harbors the majority of bacteria and apically sealing the root end by the placement of a suitable retrograde filling material. An ideal root-end filling material should be biocompatible, radiopaque, easy to handle, nonresorbable, costeffective, not affected by the presence of moisture and should seal the root canal completely.
Various existing retrograde filling materials such as amalgam, gutta-percha, glass ionomer cement, resin-modified glass ionomer cement (Vitremer), zinc oxide eugenol-based cements (Super-EBA and IRM), polycarboxylate cement, gold foil had been put forth, but unfortunately, each of these materials has various limitations and drawbacks.
Since its introduction in 1993 by Torabinejad, MTA has become a gold standard of retrograde filling materials, because of its excellent biocompatibility, superior sealing ability, bactericidal effects, ability to set in the presence of blood and its ability to promote mineralization. MTA has certain drawbacks such as the potential for tooth discoloration, difficult handling characteristics, long setting time, high cost, and absence of a known solvent for this material and difficulty of its removal after setting.
CEM was introduced to endodontics in 2006 by Asgary et al. The cement has favourable film thickness, flow and primary setting time. It sets in an aqueous environment and may promote the differentiation of stem cells and induce hard tissue formation.
As an alternative to MTA, ERRM has been introduced to dentistry as a ready to use material by Brasseler USA (Savannah, GA). According to the manufacturer, ERRM can set using moisture present in dentinal tubules. Fast setting and superior handling characteristics are its added advantages over MTA.
In endodontics, biomechanical instrumentation generates a thin adherent layer covering dentin known as the smear layer, which might affect apical leakage as it affects the ability of retrofilling material to adapt to the dentinal wall.
Apical leakage of retrograde filling materials has been evaluated by different methods such as dye/ink, bacterial/endotoxin penetration, fluid filtration technique and 3-dimensional methods such as scanning electron microscope and cone-beam computed tomography. Among the methods mentioned above, dye penetration is safe, simple, affordable, accessible and can be quantitatively assessed.
Various studies have been conducted till date to evaluate leakage using dye penetration method but to the best of our knowledge no study till date has compared apical sealing of MTA, CEM and ERRM with and without smear layer in retrofilled root-end cavity.,,
So, the purpose of this invitro study was to evaluate the apical leakage of 3 different bioceramic retrofilling materials MTA, CEM and ERRM with and without smear layer. The null hypothesis tested was that the presence or absence of smear layer in the root-end cavity did not affect the mean apical leakage of the bioceramic retrofilled cavity.
| Materials and Methods|| |
Sixty freshly extracted human single-rooted teeth (incisors, canines and premolars) were collected. Teeth were stored in buffered isotonic saline solution to clean off blood and saliva. All the teeth were verified using preoperative radiographs for the absence of multiple canals, calcifications, root resorption and severe apical curvatures.
Teeth were then decoronated at the cementoenamel junction with a #701 carbide fissure bur (D and Z, Germany) in a high-speed handpiece under continuous water spray. Root length was standardized at 13 mm. The gross pulp tissue was removed. A #10 file (Dentsply Maillefer, Ballaigues, Switzerland) was introduced into the canal until its tip could be seen at the apical foramen. The teeth were instrumented with a crown-down technique with Pro taper rotary files (Dentsply Maillefer, Ballaigues, Switzerland) at 300 rpm up to master apical size F4 (40/.06). The canals were irrigated after using each file with 5% sodium hypochlorite (2 mL) and 17% ethylene-diaminetetra acetic acid (EDTA, 2 mL). The canals were finally irrigated with distilled water and dried with paper points (Coltene, Whaledent, Germany). Canals were then obturated with corresponding gutta-percha (Dentsply Maillefer, Ballaigues, Switzerland) and AH Plus sealer (Dentsply, Konstanz, Germany) using the cold lateral compaction technique. Coronal 3 mm of filling material was removed, and the cavity was filled with flowable composite (Prevest Den Pro, India). The roots were then stored in a closed glass container after wrapping with moist gauze at room temperature and 100% humidity for 1 week before subjecting to root resection and root-end preparation.
The apical 3 mm of root tips of all teeth were resected at 90° to the longitudinal axis of the teeth using carbide fissure bur (D&Z, Germany). A root-end cavity (3 mm deep) using ultrasonic root-end preparation tips (Pro Ultra, Dentsply) were made. All the specimen teeth with prepared root-end cavities were randomly divided into 2 groups, smear (+) and smear (−), depending on the presence or absence of the smear layer. In the smear (+) group, the prepared root-end cavity was rinsed with distilled water (10 mL) only. In the smear (–) group, the prepared root-end cavity was treated with 5 mL of 17% EDTA to remove the smear layer, and then finally rinsed with 10 mL of distilled water to wash away any residual irrigant. A 23-gauge needle was used to deliver all irrigating solutions into the prepared root-end cavity.
The selected specimen teeth in each group were further subdivided into 3 subgroups based on the bioceramic retrofilling material.
Positive control group: Canals were filled with gutta percha only (n = 3).
Negative control group: Roots were completely covered by nail polish (n = 3). The retrocavities were dried with paper points and filled with the bioceramic material. Root-end cavity were retrofilled with bioceramic material. Excess material on the root surface was cleaned with moist gauze. Three layers of nail polish were applied onto the entire root surface after 24 hours, except for the root-end prepared area and left to dry. Afterward, a layer of wax was applied to the area protected with nail polish to complete sealing. The roots were then immersed in a 2% rhodamine B dye for 24 hours. Single longitudinal grooves were prepared using a diamond disc (DFS, Germany) on both labial and lingual surfaces, and a chisel was used to fracture the teeth into 2 halves under water coolant. Linear dye penetration was measured in millimetre using a stereomicroscope (Nikon SMZ25) at 10× Zoom 2 (1 μm division = 0.0123 mm) [Figure 1], [Figure 2], [Figure 3], [Figure 4], [Figure 5], [Figure 6], and the observations were analysed statistically using one way ANOVA (analysis of variance) test and unpaired Student's t test. Statistically significant differences among the groups were set at P <.05.
|Figure 1: Stereomicroscopic Image (20 X) of Apical leakage of MTA with smear layer|
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|Figure 2: Stereomicroscopic Image (20 X) of Apical leakage of MTA without smear layer|
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|Figure 3: Stereomicroscopic image (20 X) of apical leakage of CEM with smear layer|
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|Figure 4: Stereomicroscopic image (20 X) of apical leakage of CEM without smear layer |
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|Figure 5: Stereomicroscopic image (20 X) of apical leakage of Endosequence root repair material with smear layer|
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|Figure 6: Stereomicroscopic image (20 X) of apical leakage of Endosequence root repair material without smear layer |
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| Results|| |
The results were analysed by one way ANOVA, t test and Tukey's test for each mean comparision. A P <.05 was considered statistically significant.
The mean apical leakage values of bioceramic retrofilling materials with smear layer was maximum for MTA (1.70 ± 0.30) followed CEM (1.40 ± 0.37) and ERRM (1.40 ± 0.23), but the difference was not statistically significant [Table 1], Bargraph 1, [Figure 7]].
|Table 1: Mean apical leakage of different bioceramic retrofilling material with smear layer|
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|Figure 7: Bar graph 1 Showing minimum mean and maximum value of three subgroups with smear layer|
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The mean apical leakage values of bioceramic retrofilling materials without smear layer was maximum for MTA (1.80 ± 0.32) followed by CEM (1.68 ± 0.35) and ERRM (1.26 ± 0.25), and the difference was statistically significant [Table 2], Bargraph 2, [Figure 8]].
|Table 2: Mean apical leakage of different bioceramic retrofilling material without smear layer|
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|Figure 8: Bar graph 2 Showing minimum mean and maximum value of three subgroups without smear layer|
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Comparison of apical leakage values of bioceramic retrofilling materials with smear layer using ANOVA and Tukey's test showed no statistically significant difference (P >.05), which demonstrates that presence of smear layer has no significant effect on the apical leakage of different bioceramic retrofilling materials used in this study [Table 3].
|Table 3: Intergroup comparison of apical leakage of different bioceramic retrofilling materials with smear layer (ANOVA)|
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Comparison of apical leakage of different bioceramic retrofilling materials without smear layer using ANOVA and Tukey's test showed statistically significant difference (P <.05), which demonstrates that absence of smear layer has a significant effect on the apical leakage of different bioceramic retrofilling materials used in this study [Table 4].
|Table 4: Intergroup comparison of apical leakage of different bioceramic retrofilling materials without smear layer (ANOVA)|
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Without a smear layer, ERRM demonstrates least mean apical leakage value, which was statistically significant as compared with CEM (P <.05) and MTA (P <.01) [Table 5].
|Table 5: Post hoc test for apical leakage of retro-filling materials (TUKEY HSD)|
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Comparison of apical leakage values of a particular retrograde filling material with and without smear layer using Student's t test demonstrated no statistically significant difference, which depicts that presence or absence of smear layer does not affect apical leakage value of bioceramic retrofilling materials.
| Discussion|| |
Persistent apical periodontitis that does not resolve through nonsurgical treatment needs periradicular surgery that involves root resection, preparation and placement of retrograde filling material into the root-end cavity. Various retrograde filling materials are available for root-end cavity, but none has proved to be an ideal material. MTA has been widely used as a retrofilling material in endodontic surgery. Two new recently introduced material CEM and ERRM are believed to be similar to MTA in clinical applications but with improved handling characteristics. Smear layer is removed by various methods, including chemical, ultrasonic and laser techniques, none of which proved to be fully capable or are universally accepted. So far, the most commonly used method of smear layer removal has been the chemical method using chelating agents, with EDTA being the most common agent.
In the present study, dye leakage was used to evaluate the apical leakage of different Bioceramic retrofilling materials. Different dyes have been used for dye penetration studies, which include India ink, methylene blue and rhodamine B dye. In this study, 2% rhodamine B dye was used to evaluate apical leakage of different bioceramic retrofilling materials with and without smear layer. Research has suggested that dye particles such as rhodamine B are considerably smaller than microorganisms and their byproducts. Thus, if retrograde filling material does not allow the penetration of dye particles, then it has the potential to prevent leakage of bacteria and their byproducts.
The present study evaluated the apical leakage potential of 3 different retrograde filling materials, MTA, CEM and ERRM in the presence or absence of smear layer using dye penetration method.
In this study, all the experimental subgroups demonstrated dye penetration irrespective of the material used. The positive control displayed total dye penetration, while the negative control showed no evidence of dye penetration. The lowest mean apical leakage was demonstrated by ERRM without smear layer [1.26 mm ± 0.25], and the highest apical leakage was shown by MTA without smear layer [1.80 mm ± 0.32].
When apical leakage exhibited by MTA was compared, the mean apical leakage score of subgroup 1A (MTA with smear layer) [1.70 mm], was less than subgroup 2A (MTA without smear layer) [1.80 mm], but the result was not statistically significant (P >.05). This is in agreement with the study conducted by Kubo et al. in 2005, in which the least dye penetration was observed in MTA, where no demineralizing agent (1.89 mm) was used in comparison to MTA, which was subjected to 17% EDTA solution (2.64 mm).
Yildirim et al. also showed that MTA with smear layer showed less leakage than MTA without smear layer. The decrease in leakage may be attributed to the hydrophilic properties of MTA. The smear layer might act as a “coupling agent”, strengthening the bond between the MTA and root canal dentin.
When apical leakage exhibited by CEM was compared, the mean apical leakage score of subgroup 1B, (CEM with smear layer) [1.40 mm] was less than subgroup 2B, (CEM without smear layer) [1.68 mm], but the result was not statistically significant (P >.05). The possible reason for this could be that CEM has putty-like consistency and is not able to penetrate the dentinal tubules, so removal of the smear layer has paved the way for dye leakage.
When apical leakage exhibited by ERRM was compared, the mean apical leakage score of subgroup 1C (ERRM with smear layer) [1.40 mm] was more than subgroup 2C (ERRM without smear layer) [1.26 mm], but the result was statistically not significant (P >.05). The possible reason for this could be the presence of a smear layer that had prevented the penetration of smaller size ERRM particles into dentinal tubules, but in the absence of a smear layer, ERRM particles would have optimally penetrated the dentinal tubules, thereby decreasing apical leakage.
It was noteworthy to mention that mean apical leakage of CEM was less as compared with MTA, both in the presence and absence of smear layer but the result was not statistically significant (P >.05). This result is in concurrence with the study of Asgary et al. in which the mean apical leakage value of CEM was lower than the mean apical leakage value of MTA. The possible reason for this could be the better handling characteristics and chemical properties. When different retrograde filling materials were compared in the presence of smear layer, mean apical leakage value of ERRM (1C) [1.40 mm] was comparable with CEM (1B) [1.40 mm], but lesser than MTA (1A) [1.70 mm]. Still, the result was not statistically significant (P >.05) [Table 3]. The possible reason for this may be due to the presence of a smear layer that had limited the optimum penetration of Endosequence particles into dentinal tubules. When different retrograde filling materials were compared in the absence of smear layer, the mean apical leakage value of Endosequence (2C) [1.26 mm] was lower as compared with MTA (2A) [1.80 mm], and CEM (2B) [1.68 mm, [Table 4]] and the result was statistically significant (P <.01) and (P <.05), respectively [Table 5]. The probable reason could be that in the absence of smear layer, the smaller particle size of Endosequence would have allowed the premix material to penetrate into dentinal tubules and thereby bond to adjacent dentin, which in turn would have reduced the amount of apical leakage.
| Conclusions|| |
Within this study's limitations, it can be concluded that all Bioceramic retrofilling materials demonstrated apical leakage irrespective of the presence or absence of the smear layer. When the smear layer was removed, the amount of apical leakage was least shown by ERRM, while it was the most in case of MTA. When the smear layer was left intact, the apical leakage observed was least in 'MTA, while it was the most in ERRM. Therefore, the presence of a smear layer is beneficial for the sealing ability of MTA and CEM, whereas, the absence of a smear layer is advocated while using ERRM.
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Conflicts of interest
There are no conflicts of interest.
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Dr. Huma Iftekhar
Department of Conservative Dentistry and Endodontics, AMU, Aligarh, Uttar Pradesh
Source of Support: None, Conflict of Interest: None
[Figure 1], [Figure 2], [Figure 3], [Figure 4], [Figure 5], [Figure 6], [Figure 7], [Figure 8]
[Table 1], [Table 2], [Table 3], [Table 4], [Table 5]