Abstract
Aim
To evaluate the microleakage of newer bioceramic root-end filling materials.
Material and method
Sixty freshly extracted human single-rooted mandibular premolar teeth were selected for the study. Teeth with fractured root, cracks, anddilacerations were rejected. All teeth were cleaned with ultrasonic scalers. Standard access opening was done and root canal treatment was performed with rotary files followed by obturation. After storing in saline for a week apical 3 mm of the root was resected at 900 angles to the long axis of the root. Retro cavity preparation was done with ultrasonic tips. The teeth were divided into four groups of 15 specimens each. Group I - Biodentin, GroupII–Bioaggregate, Group III – MTA Plus, and Group IV – MTA. After the restoration of retro cavities of all the teeth as per manufacture instructions, two coats of nail varnish were applied to leave apical 3 mm. All teeth were stored in 2% methylene blue for 72 h followed by emersion in 65% nitric acid for the next 72 h for Dye extraction. The obtained supernatant solution was then centrifuged and optical density or absorbance was measured with a UV spectrophotometer.
Result
Microleakage was found to be increasing in this order: Biodentin < Bioaggregate < MTA Plus < MTA. No significant difference was found in the microleakage of Biodentin compared to that of Bioaggregate(p > 0.01).
Conclusion
All materials exhibit some amount of microleakage. Biodentin shows the least microleakage among all the bioceramic material groups. Hence, Biodentin and bioaggregate are better material of choice for the retrograde filling to prevent microleakage.
Keywords: Micro-leakage, Bioceramic, Root canal filling, Root-end filling material, MTA
1. Introduction
Proper biomechanical preparation and chemical disinfection results in the elimination of all endodontic microflora from the root canal and promote healing.1 Root canal treatment success also depends on the complete obliteration of the root canal by obturation to obtain a hermetic seal which prevents oral bacteria and bacterial toxins from entering the periradicular tissues.2,3 However, when conventional endodontic treatment fails, surgical endodontic treatment is done, which includes root resection and retrograde filling with a biocompatible root-end filling material.4,5
Irrespective of material used for retrograde filling, a microscopic gap always exists between the walls of retro cavity preparation and root-end filling material. Numerous materials have been used in the past such as amalgam, gutta-percha, IRM, GIC, bonding agents, but microleakage is still evident despite constant evolution and development of newer retrograde filling materials.6 Recently newer bioceramic materials have been launched such as Biodentin, Bioceramic putty, Bioaggregate, iRoot BP plus which have shown less microleakage compared to older materials. Hence this study was conducted, to evaluate the microleakage of various new bioceramic root-end filling materials.
2. Material and methods
The ethical clearance was obtained from the Institutional review coittee (VSDC/846/2016).The study was conducted as a part of three years of master’s program. Sixty mandibular premolars (single-rooted teeth with the single canal) extracted as a part of orthodontic treatment were used for the study followed by thorough ultrasonic cleaning to remove superficial stains and debris. After taking preoperative radiographs to confirm the root canal outline, root canal treatment was performed. A 10size K-file was used initially to confirm canal patency. Canals were prepared with rotary files (Protaper, Dentsply) using 5.25% sodium hypochlorite and 17% EDTA as irrigants and enlarged till F3. Canals were completely dried using paper points and obturation was done by lateral compaction technique using zinc oxide eugenol sealer after verifying master cone x-ray. A postoperative x-ray was taken to check the quality of obturation. The access cavities were restored with GIC. The treated teeth were kept in saline for one week.
The apical 3 mm of each root was resected at 90°, perpendicular to the long axis of the tooth, under copious water spray with diamond burs in a high-speed handpiece perpendicular to the long axis of the tooth. Retrograde cavity was prepared in resected root-end to a depth of 3 mm parallel to the long axis of the tooth with each ultrasonicretro tips (Pro surgical endo tips, Dentsply). Endodontic plugger was placed into the root-end cavities to check standardized cavity width and depth. The prepared retro-cavities were cleaned and irrigated with saline and dried. The teeth were then divided into four groups(N = 15).
Group I - Biodentin (Septodont, France),
GroupII–BioAggregate (Innovative Bioceramix, Canada)
Group III –MTA plus(Avalon Biomed, USA)
GroupIV–MTA (Angelus, Brazil)
After dividing teeth into respective groups, prepared retrograde cavities were restored with a respective retrograde filling material as per manufacture instructions. After the restoration of all the teeth, they were coated with two coats of varnish except at the apical 3 and then were allowed to dry. All samples were stained with 2% methylene blue for 72 h in different containers for Group I, Group II, Group III, Group IV. After this roots of the teeth were rinsed with water to remove any dye residues and varnish with a scalpel blade. Each tooth sample was stored in a sealed vial containing 65% HNO3 for 72 h for extraction of the dye. The vials were then, centrifuged at 14,000 RPM for 5 min to separate gutta-percha debris from the extracted dye. The dye concentration was evaluated using a UV spectrophotometer (Datacolor 500 UV, USA) at 550 nm using nitric acid as a blank to determine Dye concentration.
3. Statistical analysis
Data collected were categorized and tabulated into Microsoft 2013 excel sheet and were subjected to statistical analysis using IBM SPSS software vs. 23 for Windows (New York, USA). The mean depth of microleakage and Standard Deviation was calculated for each material followed by pair wise comparison using Tukey Post Hoc.
4. Results
The microleakage was highest for MTA, followed by MTA Plus and Bioaggregate, and was least for Biodentin i.e. 1.35 ± 0.24, 1.29 ± 0.36, 1.09 ± 0.37 and 0.79 ± 0.44 respectively. Thus making Biodentin the best material followed by Bioaggregate and MTA Plus (Table 1).
Table 1.
Comparison of microleakage among four groups based on optical density.
| Material Used | Mean ± S.D | F | P-Value |
|---|---|---|---|
| Biodentin | 0.79 ± 0.44 | 7.514 | .001 |
| MTA | 1.35 ± 0.24 | ||
| Bioaggregate | 1.09 ± 0.37 | ||
| MTA Plus | 1.29 ± 0.36 |
When a Pairwise comparison was carried out using Tukey Post Hoc it shows that the Bioaggregate and Biodentin showed a statistically significant difference with a mean difference of −0.55 and −0.50 (P = 0.001 and 0.002 respectively) and MTA Plus shows no statistically significant difference when compared with MTA. While a Statistically non significant difference in mean dye absorbance was noted when the MTA Plus group was compared with Bioaggregate and Biodentin. The non-significant difference was also seen when Biodentin was compared with Bioaggregate (P = 0.423 respectively) (Table 2).
Table 2.
Pair-Wise Comparison of Microleakage of four different groups.
| (I) Reference Group | (J) Comparison Group | Mean Difference (I-J) | Std. Error | 95% Confidence Interval |
P-Value | |
|---|---|---|---|---|---|---|
| Lower Bound | Upper Bound | |||||
| MTA | Biodentin | -.55667 | .12973 | -.9002 | -.2132 | .001 |
| MTA Plus | -.30067 | .12973 | -.6442 | .0428 | .106 | |
| Bioaggregate |
-.50000 |
.12973 |
-.8435 |
-.1565 |
.002 |
|
| MTA Plus | Biodentin | .25600 | .12973 | -.0875 | .5995 | .210 |
| Bioaggregate |
.05667 |
.12973 |
-.2868 |
.4002 |
.972 |
|
| Biodentin | Bioaggregate | -.19933 | .12973 | -.5428 | .1442 | .423 |
5. Discussion
Root end filling is the procedure in which biocompatible materials packed into the retrograde cavity.7 There are many materials used in the past like amalgam, GIC, Gutta-percha, IRM to provide a good seal. However, an ideal retrograde filling material fulfilling all the ideal requirements such as biocompatibility, adherence to the prepared walls, and formation of a fluid tight seal in the root canal system is difficult to achieve.8 In old times amalgam was considered the material of choice for root end filling. In recent times MTA has been developed which fulfils almost all the requirements of an ideal root end filling material and has become the gold standard against which the newer materials are compared. Thus this study was conducted to evaluate microleakage of various newer bioceramic root-end filling materials.
Numerous studies in the past have reported that teeth with root-end filling after root resection gave a good response and better healing as compared to those which are not filled.9, 10, 11 Various methods have been used to assess the microleakage in routine studies. Methods include fluid filtration, bacterial penetration, dye penetration, radioisotope, dye extraction. The most popular and widely used method is the dye penetration method. However, the main limitation of this technique is that fewer chances are there, that cut will penetrate through the area of deepest dye penetration on the random cutting of root into two pieces. This results in an underestimation of the penetrated dye and provides qualitative results.12
The dye extraction method was used in the present study. This method was selected because dye which leaks through the apex of the resected root is measured quantitatively by analyzing the optical density of the supernatant solution by using a spectrophotometer. Hence it provides more reliable quantitative results in microleakage studies as compared to the dye penetration method.13
Bioceramic root-end filling materials have given promising results as compared to traditional materials. Biodentine is calcium silicate-based cement that can be used for dentin replacement as it is bioactive, biocompatible, and has excellent sealing properties. Biodentine is similar to MTA in composition. It is easier to use as compared to MTA as it is available as a predosed capsule and also has the advantage of improved physical properties. This new bioactive material on contact with mesenchymal stem cells induces differentiation of fibroblasts and osteoblasts resulting in cementogenesis, osteogenesis, and formation of the periodontal ligament.14,15
Bioaggregate is a relatively new bioactive material which is a powder cement mixture for dental procedures. The powder contains tricalcium silicate, dicalcium silicate, calcium phosphate monobasic, amorphous silicone dioxide, and tantalum oxide as a radiopacifier. The liquid is deionized water. It is aluminium free and based on the concept of nanotechnology which produces fine ceramic particles. These fine ceramic particles on reaction with water produce biocompatible ceramic biomaterial.15 There are only a few studies available about this material, but its results have been promising.
MTA Plus is a new material with a composition similar to MTA Angelus. The particle size is much smaller and fine in MTA plus as suggested by the manufacturer. MTA Plus comes with a pre-measured water ampule for mixing.MTA plus manufacturers claim that these materials have good handling properties and biological properties which makes it suitable for root-end filling.
The results of our study showed that the microleakage was highest for MTA, followed by MTA Plus and Bioaggregate, and was least for Biodentin i.e. 1.35 ± 0.24, 1.29 ± 0.36, 1.09 ± 0.37 and 0.79 ± 0.44 respectively.
In our study least microleakage was shown by biodentin among all the bioceramic materials. The reason could be a shorter setting time (12 min), hydrophilicity, and mild setting expansion. The setting time is an important characteristic to define an ideal root-end filling material. The faster a material sets the lesser chances of partial material loss, alteration in the dentin-material interface, and the treatment time. A study was done by Young et al. reveals the setting time of MTA and biodentin as 275 min and 15 min respectively, making biodentin the bioactive material of choice for root-end filling.16 The greater setting expansion of Biodentin can be explained by increased accumulation of apatite crystals on its surface due to the higher release of calcium ions as compared to MTA.17
Another important determining factor is the pore diameter and volume. The larger the pore diameter, the larger the leakage along with the interface, thereby resulting in a compromised hermetic seal. Water: powder ratio greatly influences the pore diameter. The greater the water: powder ratio the larger the pore diameter. Since MTA is to be mixed manually there are higher chances of deviation from ideal w:P ratio. O n the other hand, Biodentin is available in a predosed formulation with a lower W:P ratio, resulting in a smaller pore size than MTA.18, 19, 20 The decreased pore volume and porosity of biodentin as compared to MTA may contribute to better sealing.21
The sealing ability of biodentin may be attributed to the increased formation of apatite crystals, as compared to MTA, at the interface between biodentin and cavity wall. This results in a fluid tight seal and prevents egression of bacteria and their toxins into the periapex; and also prevents the ingression of periradicular fluid, which nourishes the surviving bacteria, into the root canal system; eventually leading to entombment of the bacteria. It is important to stress that the coronal seal is as important as the apical seal by bioceramic materials to ensure success. The study conducted by Han and Okiji also reports higher apatite formation in biodentin when compared to MTA.22
The results of our study are similar to a previous study conducted by Radeva et al. and Khandelwal et al., who concluded that biodentin has better sealing ability compared to MTA.23,24 The study by Ravichandra et al. concluded that biodentin exhibited a better marginal seal than MTA and GIC.25
The good sealing ability of bioaggregate is due to nano-ceramic particles in its composition which provide excellent bonding to root canal walls. Bioaggregate also shows setting expansion because of its hydrophilicity which provides an additional seal.26
The better performance of MTA Plus as compared to MTA is due to its fine particle size (less than 1 μm) and the presence of an anti-washout gel. Both of these factors increase the anti washout resistance of MTA Plus.27,28
Results and methods of our study are also in accordance with the latest study done by Manisha et al. (2020) which stated that newer bioceramic materials show less microleakage as compared to conventional root-end filling materials like GIC.29
6. Limitations
The study was carried out with a relatively small sample size utilizing Dye and Spectrophotometer instead of using Scanning Electron Microscope (SEM) or Confocal Microscope which could have given much more detail and reliable results. Hence, further studies with an increased number of samples are required.
7. Conclusion
The present study concluded that all materials showed microleakage. However, the least microleakage was seen in the case of biodentin. Hence these newer bioceramic root-end filling materials are better compared to conventional materials.
Funding
None.
Ethical clearance
The ethical clearance was obtained from the Institutional review coittee of V.S Dental College, India (VSDC/846/2016).
Authors’ contributions
All authors contributed to the work.
Declaration of competing interest
The authors declare no conflict of interest.
Acknowledgment
None.
Contributor Information
Ravi Gupta, Email: ravigupta641@gmail.com.
Radhika Kewalramani, Email: radhika017@gmail.com.
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