ORIGINAL RESEARCH


https://doi.org/10.5005/jp-journals-10024-2816
The Journal of Contemporary Dental Practice
Volume 21 | Issue 4 | Year 2020

Evaluation with Micro-CT of the Canal Seal Made with Two Different Bioceramic Cements: GuttaFlow Bioseal and BioRoot RCS


Edoardo Bianco1, Chiara Calvelli2, Claudio L Citterio3, Alberto Pellegatta4, Pier M Venino5, Marcello Maddalone6

1–6Department of Medicine and Surgery, University of Milano-Bicocca, Hospital San Gerardo, Monza, Italy

Corresponding Author: Edoardo Bianco, Department of Medicine and Surgery, University of Milano-Bicocca, Hospital San Gerardo, Monza, Italy, Phone: +39392333485, e-mail: edoardo.bianco13@gmail.com

How to cite this article Bianco E, Calvelli C, Citterio CL, et al. Evaluation with Micro-CT of the Canal Seal Made with Two Different Bioceramic Cements: GuttaFlow Bioseal and BioRoot RCS. J Contemp Dent Pract 2020;21(4):359–366.

Source of support: Nil

Conflict of interest: None

ABSTRACT

Aim: The aim of this work is to investigate the quality of root canal seals obtained by comparing two bioceramic cements, GuttaFlow bioseal and BioRoot RCS, focusing on the presence of voids created during the canal obturation procedure.

Materials and methods: The voids are analyzed using a micro-computed tomography (micro-CT) device. The study will be performed using images of the endodontic space before and after filling of a selected group of elements. Furthermore, the average thickness of the cement, the average quantity of gutta-percha compared to the total shaped volume, and the average quantity of the two cements, GuttaFlow bioseal and BioRoot RCS, with respect to the total shaped volume were considered. The apical, middle, and coronal thirds have been investigated in a sectorial manner. Images have been analyzed using a CT-An™ software and visualized through a three-dimensional (3D) reconstruction of the slices by the software CT-Vol™. Shapiro–Wilk test/Test D’Agostino-Pearson/Kolmogorov–Smirnov test were used to ensure the reliability of results.

Results: No significant differences were observed in the amount of gutta-percha compared to the shaped volume between the GuttaFlow bioseal group and BioRoot RCS. No statistically significant difference was observed between the two groups in terms of voids.

Conclusion: The data obtained from this study allowed to conclude that the samples filled with GuttaFlow bioseal and BioRoot RCS have a similar seal capacity since no statistically significant differences were observed between the two groups. No sample showed the absence of voids within the root canal obturation.

Clinical significance: Even if the two cements tested showed differences in terms of void volume and ability to fill thin spaces, they should be considered both acceptable and equivalent in terms of clinical sealing ability.

Keywords: Abfraction, Air void, Bioceramic, Endodontic cement, Gutta-percha, Laboratory research, Micro-CT, Occlusion.

INTRODUCTION

The endodontic treatment is the basis of all procedures designed to preserve and recover decayed dental element.1 Cements belonging to the category of bioceramics guarantee not only a good root canal seal but also a positive interaction with the surrounding tissues. The release of calcium ions and the basic pH in fact favor the healing of periapical lesions and stimulate a process of mineralization, resulting in a real interaction with dentin. Unlike materials of the past generations, they are easier to handle, even in the presence of moisture.

The bioactivity of these cements, combined with their antimicrobial and stimulating power, makes them completely different from the materials most used in endodontic practice. To these cements, an equally satisfactory filling capacity must be added. The quality of the root canal seal that these cements guarantee can be studied using the ultra-high-resolution three-dimensional (3D) technology of the micro-computed tomography (micro-CT) and the software dedicated to it.

In the following decades, the morphology of the canal system was studied using both the techniques yet described and other innovative techniques as well as in other disciplines.18

The quality of the endodontic treatment depends on an appropriate cleaning, root canal shaping, and creating 3D model and filling obturation of the intraradicular space: the main objective to be achieved in the obturation is to reduce the formation of voids within the canal system and not to give rise to bacterial infiltration both in the apical and in the coronal directions. The various phases of therapy are essential to achieve this goal: cleaning coupled with an antibacterial effect with the ability to remove debris and smear layer derived from shaping.

Over the past 150 years, an ample selection of filling materials was tested, but no one like gutta-percha has proven to possess the suitable properties. The ideal requirements for a filling material were first set out by Brownlee and then by Grossman.9,10

Bioceramic cements satisfy many of these requirements as they release calcium ions, show an alkaline and an antimicrobial effect, offer a good penetration in root canals, promote tissue regeneration, and must have adequate radiopacity and good adhesion.11,12

The aim of this work was to investigate the quality of the root canal seal obtained by comparing two bioceramic cements, GuttaFlow bioseal and BioRoot RCS, focusing on the presence of voids created during the canal obturation procedure. The analysis was performed using micro-CT images of the endodontic space before and after filling of a selected group of elements.

Furthermore, the average thickness of the cement, the average quantity of gutta-percha compared to the total shaped volume, the average quantity of the two cements, GuttaFlow Bioseal and BioRoot RCS, with respect to the total shaped volume, and the amount of voids detected in the overall canal volume were considered. The apical, middle, and coronal thirds were also investigated in a sectorial manner.

MATERIALS AND METHODS

For this study, 15 permanent human teeth, for a total of 24 canals, were obtained; 10 teeth were extracted from upper arch and 5 from lower arch (Table 1). Teeth were extracted at San Gerardo Hospital in Monza, and the study was conducted at the Department of Medicine and Surgery, University of Milano Bicocca, Monza.

The sample consisted of all types of tooth, both single and multiple rootlet (the single root canal was analyzed and not the whole tooth), in order to obtain a greater morphological heterogeneity of the root canal anatomy and therefore to get closer to the everyday clinical experience.

The inclusion and exclusion criteria for sample selection were as follows.

Inclusion Criteria

  • Human dental elements were extracted for periodontal, orthodontic, and traumatic reasons. The elements were extracted atraumatically and without using rotating burs.
  • Elements without any root fracture after extraction.

Exclusion Criteria

  • Teeth with previous endodontic therapies (root canal therapy, pulpotomy, apex formation, etc.)
  • Teeth with atresic endodontic system or apical resorption.
Table 1: Sample subdivision: GuttaFlow bioseal and BioRoot RCS
Tooth numberRoot canalsType of instrumentationType of cement
211ReciprocGuttaFlow bioseal
341ReciprocBioRoot RCS
151ReciprocBioRoot RCS
472ReciprocGuttaFlow bioseal
183ReciprocBioRoot RCS
373HyflexGuttaFlow bioseal
341HyflexGuttaFlow bioseal
241HyflexBioRoot RCS
142HyflexGuttaFlow bioseal
242HyflexGuttaFlow bioseal
242HyflexBioRoot RCS
331HyflexBioRoot RCS
251HyflexGuttaFlow bioseal
152HyflexBioRoot RCS
141HyflexBioRoot RCS

The teeth used in this work were incorporated into a transparent thick epoxy resin (Artidee® XOR Crystal®, Lindenberg, DE). It is a transparent and glossy bicomponent epoxy formulation suitable for incorporation of organic objects. It was chosen because the material shows a good degree of hardness and transparency. It also has a radiopacity that does not interfere with the micro-CT analysis. For the mixing of the resin, the instructions provided by the manufacturer were followed.

A cylindrical metal mold with a height of 4 cm and an internal diameter of 3 cm was used for casting. Inclusion took place in two phases. In the first phase, a resin base of about 1 cm was created. Subsequently with the help of a layer of blue wax, the dental elements were positioned and immersed in a second resin casting up to the level of the anatomical crown. In this way, easy orthograde access to the root canal system was allowed. The wax also allowed to avoid the occlusion of the apical foramen by the material.

The use of the micro-CT allowed a quantitative and qualitative evaluation of the preparation of the root canals in the three dimensions of the space. The micro-CT equipment used for the analysis was a SkyScan 1176 (SkyScan® Bruker Biospin).

In order to obtain the best image quality and therefore analyze in detail the root canal system, the maximum resolution of the machine (9 μm) was used. The volumetric reconstructions were automatically reprocessed by the software with an axial pattern of 9 μm cuts. Moreover, in order to have further details on the root, canal, and chamber anatomy of the elements, cross sections were made starting from the axial ones using the DataViewer software (SkyScan®). Also thanks to the software it was possible to obtain 3D volumetric reconstructions of the root canal filler, cross sections of the root that allow to evaluate the canal width, and finally an axial reconstruction to evaluate the canal form and the area of the latter along the entire length of the root.

Canal Shaping

The elements were subjected to canal shaping using two different types of nickel titanium instruments. A group of 5 teeth was instrumented using Reciproc Instruments, the remaining 15 elements were shaped by Hyflex according to the manufacturer’s prescriptions.

The working length was calculated based on the measurements derived from the two-dimensional micro-CT images, since the apical detector could not be used due to the resin inclusion of the elements.

Access to the pulp chamber was obtained using a red handpiece with Intesiv 206 cutters, and Butt cutters were mounted for the finishing of the chamber walls. Mechanical instrumentation was associated with the use of root canal irrigants: 5.25% sodium hypochlorite and 17% EDTA.

Canal Obturation

In the next phase of the work, the samples were subjected to root canal obturation. Since time has elapsed between the two phases, due to the micro-CT scans, we again decided to previously irrigate the shaped canals.

It was carried out by washing with EDTA. At the same time, ultrasounds were used for 1 minute using a Satelec device with an insert dedicated to canal irrigation (satelec punta irrisafe).

Finally, the samples were subjected to washing with distilled water and dried with paper cones.

For root canal obturation, the teeth were divided into two groups: in one group, the filling material includes gutta-percha cones and GuttaFlow bioseal; while in the second group, gutta-percha and BioRoot RCS cones are used.

The elements have been divided, so that each group consists of 12 channels, and the present canals were instrumented with both Hyflex and Reciproc. The division of the samples took place randomly but guided by the following criteria:

  • The two groups must have the same number of channels. In the GuttaFlow group, 3 of the 12 channels were instrumented with Reciproc and 9 with Hyflex. In the BioRoot group, 5 of 12 channels were instrumented with Reciproc and 7 with Hyflex.
  • Multirooted teeth must have the same obturation method to avoid mixing cement through possible root canal communication and errors during the micro-CT image analysis phase.
  • The two groups must be as homogeneous as possible in relation to the root canal instrumentation and the types of teeth present.

Respecting these criteria, the teeth were divided as presented in Table 1.

The obturation technique used to complete the obturation of the endodontic system was on the method of the single cone without vertical compaction. In fact, the cold technique is indicated by the producers of BioRoot and GuttaFlow bioseal. The bioceramic cements in fact harden in the presence of moisture, absorbing water from the surrounding environment and going against a slight expansion. Any use of heat during the hot compaction techniques of gutta-percha can alter the environment of the canal space and interfere with the hardening of the cement itself.

The elements after filling were scanned at the micro-CT for the third time (Fig. 1)

The CT-Analyzer (CTAn), the software used for the analysis of the scans, is an application for measuring quantitative parameters and reconstructing 3D models starting from micro-CT scans obtained through SkyScan devices. The CTAn (SkyScan®) allows to manage the reconstructions of 3D volumes and, by creating a customized algorithm of plug-ins, to calculate volumes and surfaces.

The focus was, therefore, on the study of:

  • Volume of gutta-percha
  • Cement volume
  • Shaped volume and presence of voids in the canal seal

From these values, others were obtained:

  • Volume of voids: obtained as the difference of the shaped volume minus the blocked volume.
  • Total volume obturated: sum of the volume occupied by cement and gutta-percha.

Different task lists were created, one for the reconstruction of the shaped volume, one for the reconstruction of the gutta-percha volume, and one for the volume of the canal cement. From each task list, a 3D reconstruction of the isolated and analyzed volume was obtained.

STATISTICAL ANALYSIS

Statistical analysis was performed using the GraphPad Prism 7 software.

Shapiro–Wilk, D’Agostino–Pearson, and Kolmogorov–Smirnov tests were performed to assess the statistical normality. Student t test was performed for data with normal distribution, while Mann–Whitney U test was performed for data otherwise. Statistical significance was set at p %3C; 0.05.

For each sample, the root canal volume is divided into three sections (the apical, middle, and coronal third). For each section, we calculated the amount of vacuum present. After performing the normal tests, the data collected for each third were analyzed in order to assess whether there is a significant difference in the meanings between the considered root canal portions.

RESULTS

The 15 dental elements belonging to the study were divided into two groups consisting of 12 canals each, with respect to the criteria mentioned above. The samples underwent a root canal shaping phase and an endodontic obturation phase using two different types of bioceramic cements examined for this study. The following tables show the results for the two groups (Tables 2 and 3).

Since this study aimed to evaluate the quality of the root canal seal in relation to the presence of voids left by the sealer within the endodontic space, attention has been given to how these voids are distributed along the canal. The volume of interest analyzed previously was then divided into three portions (one apical area, one middle, and one coronal); and for each of them, a new search for the voids was carried out (Tables 4 and 5).

Figs 1A and B: (A) Micro-CT section: cross sections of the filled root that evaluated the canal width; (B) Axial section to evaluate the canal form and the area of the latter along the entire length of the root

Table 2: GuttaFlow bioseal group
Tooth numberCanalShaped volume (mm3)Cement volume (mm3)Gutta-percha volume (mm3)Filled volume (mm3)Voids’ volume (mm3)% of vacuum on the shaped total V/S% of gutta-percha on the shaped total G/S% of cement on the total shaped C/S
211–15.886132.703392.858615.562060.324070.0550565480.4856518630.459281395
47ml 1–111.885535.592482.812238.404713.480820.2928619930.2366095580.470528449
47d1–17.534974.4382.370876.808870.72610.096364020.3146488970.588987083
37mv 1–1*4.535531.522992.901424.424410.111120.0244998930.6397091410.335790966
37mp 1–1*5.645972.19823.349585.547780.098190.0173911660.5932691810.389339653
37d1–14.858961.643963.19584.839760.01920.0039514630.6577127620.338335776
341–25.240162.1532.720224.873360.36680.0699978630.5191101040.410865317
14v 1–1*5.434731.918222.580134.498350.936380.1722955880.4747485160.352955897
14p 1–1*5.613972.76982.621325.391120.222850.0396956160.4669280380.493376345
24v 1–15.099381.774232.946084.720310.379070.0743364880.5777329790.347930533
24p 1–1*4.516782.221711.894384.116090.400690.0887114270.4194094020.491879171
251–25.240162.145152.720184.873340.356410.0699977560.5191100020.410865426

* There are 2 root canals that are confluent

Table 3: BioRoot RCS group
Tooth numberCanalShaped volume (mm3)Cement volume (mm3)Gutta-percha volume (mm3)Filled volume (mm3)Voids’ volume (mm3)% of vacuum on the shaped total V/S% of gutta-percha on the shaped total G/S% of cement on the total shaped C/S
341–112.445974.46842.385226.853625.592350.4493301850.1916459710.359023845
151–19.797762.69833.017245.715544.082220.4166482950.3079520220.275399683
17m1 1–14.158431.022631.19652.219131.93930.4663538880.2877287820.245917329
17m2 1–13.860841.192932.612993.805920.054920.0142248840.6767931330.308981983
17d1–14.570311.504842.968534.473370.096940.0212108150.6495248680.329264317
24v 1–14.147110.811633.142153.953780.193330.0466180060.757672210.195709783
24v 1–16.255722.59922.667055.266250.989470.1581704420.4263378160.415491742
24p1–18.185123.456893.426726.883611.301510.1590092750.4186523840.422338341
331–15.050382.092732.895644.988370.062010.0122782840.5733509160.4143708
15v 1–1*3.729621.703131.948593.651720.07790.0208868460.5224634150.456649739
15p 1–1*5.748262.668183.078635.746810.001450.000252250.5355759830.464171767
141–17.614202.402873.403695.806561.807640.2374037980.4470187280.315577474

* There are 2 root canals that are confluent

Table 4: Data regarding voids’ distribution in the apical, medium, and coronal third of GuttaFlow bioseal group
Tooth numberCanal typeVoids’ apical third (mm3)Voids’ medium third (mm3)Voids’ coronal third (mm3)
211–10.176850.193330.12226
47ml 1–10.241900.120280.02303
47d1–10.164910.472801.93224
37mv 1–1*0.052330.032960.06844
37mp 1–1*0.015600.053840.03662
37d1–10.066610.000120.00149
341–20.000200.00010.00011
14v 1–1*0.313830.365540.02184
14p 1–1*0.258660.214080.05923
24v 1–10.099270.010410.04418
24p 1–1*0.036510.073190.13754
25v 1–10.045910.021540.08569

* There are 2 root canals that are confluent

Table 5: Data regarding voids distribution in the apical, medium and coronal third of BioRoot RCS group
Tooth numberCanal typeVoids’ apical third (mm3)Voids’ medium third (mm3)Voids’ coronal third (mm3)
341–11.65881.951971.98158
151–10.26620.088713.18951
17m1 1–10.072180.000440.2695
17m2 1–100.006340.15152
17d1–10.006720.009830.21741
24v 1–10.002770.00010.00833
24v 1–10.1810.037310.54105
24p1–10.076310.068220.91504
331–10.00920.052340.80351
15v 1–1*0.010430.01130.09756
15p 1–1*0.001080.003790.14698
14427360.224620.739821.16293

* There are 2 root canals that are confluent

Table 6: Cement % volume of BioRoot RCS and GuttaFlow bioseal at fixed thickness
Tooth numberCanal typeVoids’ apical third (mm3)Voids’ medium third (mm3)Voids’ coronal third (mm3)Canal cement
21o1–10.176850.193330.12226GuttaFlow bioseal
47o1–10.241900.120280.02303GuttaFlow bioseal
47m1 1–10.164910.472801.93224GuttaFlow bioseal
37m2 1–10.052330.032960.06844GuttaFlow bioseal
37d1–10.015600.053840.03662GuttaFlow bioseal
37v 1–10.066610.000120.00149GuttaFlow bioseal
34v 1–10.000200.00010.00011GuttaFlow bioseal
14p1–10.313830.365540.02184GuttaFlow bioseal
14o1–10.258660.214080.05923GuttaFlow bioseal
24v 1–1*0.099270.010410.04418GuttaFlow bioseal
24p 1–1*0.036510.073190.13754GuttaFlow bioseal
25v 1–10.045910.021540.08569GuttaFlow bioseal
34o1–11.65881.951971.98158BioRoot RCS
15ml 1–10.26620.088713.18951BioRoot RCS
17d1–10.072180.000440.2695BioRoot RCS
17mv 1–1*00.006340.15152BioRoot RCS
17mp 1–1*0.006720.009830.21741BioRoot RCS
24d1–10.002770.00010.00833BioRoot RCS
24o1–20.1810.037310.54105BioRoot RCS
24v 1–1*0.076310.068220.91504BioRoot RCS
33p 1–1*0.00920.052340.80351BioRoot RCS
15v 1–10.010430.01130.09756BioRoot RCS
15p 1–1*0.001080.003790.14698BioRoot RCS
14v 1–10.224620.739821.16293BioRoot RCS

* There are 2 root canals that are confluent

The voids in the apical third had a mean value of 0.122 mm3 for GuttaFlow bioseal group and 0.209 mm3 for the BioRoot in the apical third.

With Mann–Whitney U test, the z score is 0.47883. The p value is 0.63122. The result is not significant at p < 0.05, so the difference in the presence of voids in the apical portion of the teeth analyzed is not statistically significant.

The voids in the medium third had a mean value of 0.129 mm3 for GuttaFlow bioseal group and 0.265 mm3 for the BioRoot in the apical third.

With Mann–Whitney U test, the z score is 0.47883. The p value is 0.63122. The result is not significant at p < 0.05, so the difference in the presence of voids in the medium portion of the teeth analyzed is not statistically significant.

The voids in the coronal third had a mean value of 0.211 mm3 for GuttaFlow bioseal group and 0.790 mm3 for the BioRoot in the apical third.

With Mann–Whitney U test, the z-score is 0.47883. The p value is 0.63122. The result is not significant at p < 0.05, so the difference in the presence of voids in the coronal portion of the teeth analyzed is not statistically significant.

The percentage of cement distributed within two defined thickness ranges: 0.018 to 0.054 mm and 0.054 to 0.089 was also calculated using a specific task list. These values represented the smallest thicknesses that can be calculated in the program and therefore allow to evaluate the fluidity of the material (Table 6).

Fig. 2: Medium percentile values of cement on shaped (C/S)

With regard to gutta-percha compared to the shaped volume, no statistically significant difference was observed between the GuttaFlow bioseal group and the BioRoot RCS group (Fig. 2).

No difference was observed in the percentage of cement distribution between the two groups (Table 7).

DISCUSSION

The success of the endodontic treatment depends to a large extent on a 3D filling of the root canal in order to prevent bacterial residues and their toxins from infecting the periapical tissues.13,14 For this purpose, many filling materials and root canal cements have been developed. Gutta-percha is commonly used with cement to get the maximum seal. The root canal cements in fact fill the gap between the gutta-percha and the dentine walls, creating a real glue between the two. For this reason, cements are essential for the long-term success of root canal treatment.15

Table 7: Canal filling BioRoot RCS and GuttaFlow bioseal groups
Tooth typeCanal filling (%)Canal cement
3455.07GuttaFlow bioseal
1558.34GuttaFlow bioseal
1853.36GuttaFlow bioseal
1898.58GuttaFlow bioseal
1897.88GuttaFlow bioseal
2497.75GuttaFlow bioseal
2484.18GuttaFlow bioseal
2484.1GuttaFlow bioseal
3398.77GuttaFlow bioseal
1597.91GuttaFlow bioseal
1599.97GuttaFlow bioseal
1476.26GuttaFlow bioseal
2194.49BioRoot RCS
4870.71BioRoot RCS
4890.36BioRoot RCS
3797.55BioRoot RCS
3798.26BioRoot RCS
3799.6BioRoot RCS
3493BioRoot RCS
1482.77BioRoot RCS
1496.03BioRoot RCS
2492.57BioRoot RCS
2491.13BioRoot RCS
2596.32BioRoot RCS

The main cause of failure of endodontic therapies is in fact due to the bacterial micro-infiltrations that may occur between the cement and dentin, gutta-percha and cement, or through voids created in cement. Therefore, the quality of root canal filling and consequently the success of the therapy depend to a large extent on the sealing capacity of the root canal.11 Although gutta-percha and traditional cements have commonly been used for the obturation of endodontically treated teeth, this has not really overcome the problem of infiltrations. So new materials have been developed in order to improve the seal of endodontic obturation.

Bioceramic cements have recently been introduced into endodontics. Their composition based on calcium phosphates, zirconium oxides, calcium silicates, calcium hydroxides, alumina, etc. made them particularly biocompatible and bioactive toward biological tissues, so as to stimulate the healing process, the production of mineralized tissues, and an antibacterial effect given by the alkaline pH and the release of calcium ions.

Still few studies are available in the literature concerning this category of cements, and most of them focus on the analysis of their excellent biological properties. For this reason, in this study it was decided to focus on the analysis of their behavior within the root canal when used in association with gutta-percha to obtain an ideal endodontic seal.

The evaluation of the quality of obturation and of the presence of voids left by the materials (the actual cause of the micro-infiltrations) was made by using the micro-CT.

No significant difference was observed in the amount of gutta-percha compared to the shaped volume (percentage value) between the GuttaFlow bioseal group and BioRoot RCS, as can also be seen from Figure 2, representing the volume averages.

These data would further be verified if the percentage of the filled volume with the shaped volume was considered. Also in this case, we can see from the graph how the samples filled with gutta-percha and cement BioRoot RCS are less filled than the canal space of the group obturated with GuttaFlow bioseal. Taking into account that the quantity of gutta-percha is almost similar in the two groups, the difference is attributable to the amount of cement.

It is not possible to explain these results exclusively referring to a different expansion of the two materials. It is known that bioceramic cements, as opposed to traditional cements, have a slight expansion during the hardening phase due to their tendency to absorb water from the environment, in particular from the dentinal tubules. Only few studies are available in the literature; however, precise data do not yet exist that allow to quantify the actual degree of expansion of each bioceramic cement.

In Gandolfi et al. study, it was clear how the calcium silicate GuttaFlow bioseal and MTA Fillapex cements have a greater degree of water absorption compared to cements of different composition.16 However, only the data are referred to this study and the literature does not offer similar studies referring to BioRoot RCS.

Reasoning on the method used to insert the cement inside the canal seems more likely to be the actual cause of the difference in the GuttaFlow bioseal group and BioRoot RCS. In the case of GuttaFlow bioseal, the manufacturer offers a syringe containing the base and the catalyst of the cement itself. When injecting the material, the two substances are mixed at the level of the syringe nozzle, allowing the mixing also in the insertion inside the canals.

BioRoot RCS, in contrast, is not equipped with any self-mixing means. The product is supplied in the form of powder and liquid plus a measuring cup for the correct dosage of the powder.

Despite the results and conclusions just reported on the data on cement, the statistical analysis tells us that the difference in the average percentages of voids in the two groups depends on the case. Basically, therefore there is no real difference between the two groups in terms of voids and therefore we could consider the similar seal capacity for the two cements. From Figure 3 we can still see how the average voids present in the canals of the BioRoot group is double compared to the GuttaFlow group.

This could also be due to the way as to how it is inserted into the canal. A manual process in which the powder and liquid are mixed and then positioned inside the syringe, not allowing to have a tight control on the incorporation of air bubbles that do not guarantee a uniform and compact cement application inside the channel.

By evaluating how the voids are distributed within the canals of the BioRoot RCS group, it has been observed that the largest volumes of voids are found at the level of the coronal portion in an amount almost three times higher than that in the apical and middle thirds. This is also confirmed by the statistical data.

In the GuttaFlow group, however, the voids are distributed more evenly, and no statistical significance was observed between the average of the voids in the different third parties (Fig. 4).

Among all, it is important to evaluate the apical seal as this area represents much of the success of endodontic therapy.17,18 Bacterial penetration, in fact, has an easy access from the apex where at the same time it is more difficult to control during the shaping, cleaning, and obturation phases.

Fig. 3: Medium percentile of voids volume on shaped volume (V/S)

Fig. 4: Voids’ volume distributions in the apical, medium, and coronal third for the GuttaFlow bioseal and BioRoot RCS groups

As regards the percentage of cement distributed in the thickness ranges 0.018–0.054 and 0.054–0.089, no significant difference was observed between the groups, so the two cements show a similar degree of fluidity and therefore the ability to distribute in the thinner and more tortuous lateral canal structures. In general, these cements have greater thickness compared to traditional cements; in many cases, they do not even fall under the ISO 6876 standards; this, however, is not important, as these cements do not go against contraction, but conversely tend to expand, and therefore cannot undermine the quality of the seal from this point of view.

In our study, only 9 of 24 samples obtained similar results. Of these, six belong to the BioRoot RCS group and three to the GuttaFlow group (Table 6).

In analyzing the data related to the root canal filling, we find that the BioRoot RCS group has a greater number of cases with a percentage of root filling %3E;97. These data seem to contrast with what has been described so far regarding this cement.15,1921 Actually we can think that the discrepancy in the range of filled volume (53.36–99.97%) in the BioRoot RCS group can depend not only on the bubbles already present in the material but also on the degree of pressure applied to the syringe during insertion of cement in the canal. This factor is operator dependent and once again we can partially relate it to the mode of application of the cement. Comparing the filling values for GuttaFlow bioseal, it has been understood that these are more homogeneous (range 70.71–99.60%) and probably related to a prefilled syringe as well as a thin and more flexible plastic needle.

Limitation of the Study

A limit of this study is the small number of teeth analyzed and that only one method of cement application was tested; thus, it would be interesting to reevaluate the potential of the BioRoot RCS which showed a lower average percentage volume within the cement-filled canals by modifying its application technique in root canals.

CONCLUSION

Endodontic treatment is sometimes fundamental to restore tooth integrity and a correct and balanced occlusion.3,2229 In this study, GuttaFlow bioseal and BioRoot RCS were compared with the single gutta-percha cone obturation technique. They seemed to have a similar seal capacity. None of the samples showed absence of voids within the root canal obturation, and no statistically significant differences was observed between the two groups.

BioRoot RCS and GuttaFlow bioseal showed a similar degree of fluidity. At the same time, however, the BioRoot RCS cement showed a lower average percentage volume within the filled canals. This has been attributed to the technique of inserting the BioRoot RCS cement into the channels.

CLINICAL SIGNIFICANCE

Although the two cements tested showed differences in terms of the volume of voids and ability to fill thin spaces, both the cements should be considered acceptable and equivalent in terms of their clinical sealing ability.

REFERENCES

1. Song M, Kim HC, Lee W, et al. Analysis of the cause of failure in nonsurgical endodontic treatment by microscopic inspection during endodontic microsurgery. Endod 2011;37(11):1516–1519. DOI: 10.1016/j.joen.2011.06.032.

2. Venino PM, Citterio CL, Pellegatta A, et al. A micro-computed tomography evaluation of the shaping ability of two nickel-titanium instruments, Hyflex EDM and protaper next. J Endod 2017;43(4):628–632. DOI: 10.1016/j.joen.2016.11.022.

3. Tuncer S, Demirci M, Tekçe N, et al. The effect of two bulk fill resin composites on microleakage in endodontically treated teeth. J Dentists 2013;1(1):8–15. DOI: 10.12974/2311-8695.2013.01.01.2.

4. Scavia S, Roncucci R, Bianco E, et al. Minimal invasive flapless piezotome alveolar crest horizontal split technique: preliminary results. J Contemp Dent Pract 2020;21(1):28–35. DOI: 10.5005/jp-journals-10024-2743.

5. Bianco E, Rota D. Oral findings in Rett syndrome: an update and review of the literature. Dent Med Probl 2018;55(4):441–445. DOI: 10.17219/dmp/99203.

6. Citterio F, Pellegatta A, Citterio CL, et al. Analysis of the apical constriction using micro-computed tomography and anatomical sections. Giornale Italiano Di Endodonzia 2014;28(1):41–45. DOI: 10.1016/j.gien.2014.05.001.

7. Maddalone M, Gagliani M, Citterio CL, et al. Prevalence of vertical root fractures in teeth planned for apical surgery. A retrospective cohort study. Int Endod J 2018;51(9):969–974. DOI: 10.1111/iej.12910.

8. Ambu E, Citterio CL, Pellegatta A, et al. The use of limited CBCT in the early diagnosis of root vertical fracture: a case report. Glob J Oral Sci 2018;4(1):18–24. DOI: 10.30576/2414-2050.2018.04.4.

9. Brownlee WA. Filling of root canals in recently devitalized teeth. Dominion Dent J 1900;12(8):254.

10. Grossman LI. An improved root canal cement. JADA 1958;56(3):381–385. DOI: 10.14219/jada.archive.1958.0055.

11. Wu MK, De Gee AJ, Wesselink PR. Leakage of four root canal sealers at different thickness. Int Endod J 1994;27(6):304–308. DOI: 10.1111/j.1365-2591.1994.tb00273.x.

12. Weis MV, Parashos P, Messer HH. Effect of obturation technique on sealer cement thickness and dentinal tubule penetration. Int Endod J 2004;37(10):653–663. DOI: 10.1111/j.1365-2591.2004.00839.x.

13. Michaud RA, Burgess J, Barfield RD, et al. Volumetric expansion of gutta-percha in contact with eugenol. J Endod 2008;34(12):1528–1532. DOI: 10.1016/j.joen.2008.08.025.

14. Ozok AR, van der Sluis LW, Wu MK, et al. Sealing ability of a new polydimethylsiloxane-based root canal filling material. J Endod 2008;34(2):204–207. DOI: 10.1016/j.joen.2007.11.005.

15. Sönmez IS, Oba AA, Sönmez D, et al. In vitro evaluation of apical microleakage of a new MTA-based sealer. Eur Arch Paediatr Dent 2012;13(5):252–255. DOI: 10.1007/bf03262880.

16. Generali L, Prati C, Pirani C, et al. Gandolfi MG.double dye technique and fluid filtration test to evaluate early sealing ability of an endodontic sealer. Clin Oral Investig 2017;21(4):1267–1276. DOI: 10.1007/s00784-016-1878-0.

17. Celikten B, Uzuntas CF, Orhan AI, et al. Evaluation of root canal sealer filling quality using a single-cone technique in oval shaped canals: an in vitro micro-CT study. Scanning 2016;38(2):133–140. DOI: 10.1002/sca.21249.

18. Porcaro G, Busa A, Bianco E, et al. Use of a partial-thickness flap for guided bone regeneration in the upper jaw. J Contemp Dent Pract 2017;18(12):1117–1121. DOI: 10.5005/jp-journals-10024-2186.

19. Viapiana R, Flumignan DL, Guerreiro-Tanomaru JM, et al. Physicochemical and mechanical properties of zirconium oxide and niobiumoxide modified portland cement-based experimental endodontic sealers. Int Endod J 2014;47(5):437–448. DOI: 10.1111/iej.12167.

20. AL-Haddad A, Ab Aziz C, Zeti A. Review article bioceramic-based root canal sealers: a review. Int J Biomater 2016;2016: 9753210. DOI: 10.1155/2016/9753210.

21. Bianco E, Maddalone M, Porcaro G, et al. Treatment of osteoradionecrosis of the jaw with ozone in the form of oil-based gel: 1-year follow-up. J Contemp Dent Pract 2019;20(2):270–276. DOI: 10.5005/jp-journals-10024-2508.

22. Bianco E, Attuati S, Brugali C, et al. Restoration of the vertical posterior dimension in a grinding patient before orthodontic treatment: a case-report with electromyographic evaluation of masticatory muscles balance. J Dent 2019;7:38–42. DOI: https://doi.org/10.12974/2311-8695.2019.07.6.

23. Galluzzi F, Pignataro L, Maddalone M, et al. Recurrences of surgery for antrochoanal polyps in children: a systematic review. Int J Pediatr Otorhinolaryngol 2018;106:26–30. DOI: 10.1016/j.ijporl.2017.12.035.

24. Saati S, Eskandarloo A, Falahi A, et al. Evaluation of the efficacy of the metal artifact reduction algorithm in the detection of a vertical root fracture in endodontically treated teeth in cone-beam computed tomography images: an in vitro study. Dent Med Probl 2019;56(4):357–363. DOI: 10.17219/dmp/109902.

25. Krastev BP. Laser apicoectomy with ER:YAG and bone xenograft bio-Oss Collagen®. A case report. The Journal of Dentists 2014;2(2):90–95. DOI: http://dx.doi.org/10.12974/2311-8695.2014.02.02.8.

26. Grout A, Speakman EM. In-flight transmission of foodborne disease: How can airlines improve? Travel Med Infect Dis 2020;33: 101558. DOI: 10.1016/j.tmaid.2020.101558.

27. Maddalone M, Bianco E, Nanussi A, et al. Treatment of temporomandibular disorders of muscular origin with a silicon oral device (Alifix®): electromyographic analysis. J Contemp Dent Pract 2019;20(12):1367–1374. DOI: 10.5005/jp-journals-10024-2704.

28. Bianco E. Factors influencing immediate maxillary dental implant placement and bone resorption: a review of the literature and an outlook on the clinical possibilities. Dent Med Probl 2016;53(3):408–412. DOI: 10.17219/dmp/63185.

29. Silva EJNL, Canabarro A, Andrade MRTC, et al. Dislodgment resistance of bioceramic and epoxy sealers: a systematic review and meta-analysis. J Evid Based Dent Pract 2019;19(3):221–235. DOI: 10.1016/j.jebdp.2019.04.004.

________________________
© The Author(s). 2020 Open Access This article is distributed under the terms of the Creative Commons Attribution 4.0 International License (https://creativecommons.org/licenses/by-nc/4.0/), which permits unrestricted use, distribution, and non-commercial reproduction in any medium, provided you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons license, and indicate if changes were made. The Creative Commons Public Domain Dedication waiver (http://creativecommons.org/publicdomain/zero/1.0/) applies to the data made available in this article, unless otherwise stated.