ArticlePDF Available

Abstract and Figures

Aim of the study is to compare the quality of the apical seal offered by a zinc-eugenol and a tricalcium-silicate-based sealer, both used with the single-cone or with the continuous wave of condensation technique. Forty central incisors were divided into four groups (n = 10), according to the two sealers and the two obturation techniques under investigation, and their outer surface was isolated with nail varnish. After endodontic treatment, samples were immersed in methylene blue dye for 72 h, then included in self-curing resin and sectioned to longitudinally expose the canal apical third. The depth of dye penetration was measured in each group. Mean values were compared by two-way-ANOVA test. Multiple comparisons were performed by Tukey test. The level of significance was set at 0.05 in all tests. The continuous wave of condensation technique led to reduced microleakage. Moreover, dye penetration values were reduced for the tricalcium-silicate sealer. In terms of microleakage, the warm continuous wave of condensation technique seems promising even when combined to a bioceramic sealer.
Content may be subject to copyright.
coatings
Article
In Vitro Microleakage Evaluation of Bioceramic and
Zinc-Eugenol Sealers with Two Obturation Techniques
Francesco De Angelis *, Camillo D’Arcangelo, Matteo Buonvivere, Rachele Argentino and Mirco Vadini


Citation: De Angelis, F.;
D’Arcangelo, C.; Buonvivere, M.;
Argentino, R.; Vadini, M. In Vitro
Microleakage Evaluation of
Bioceramic and Zinc-Eugenol Sealers
with Two Obturation Techniques.
Coatings 2021,11, 727. https://
doi.org/10.3390/coatings11060727
Academic Editor: Jasmina Primožiˇc
Received: 22 May 2021
Accepted: 15 June 2021
Published: 17 June 2021
Publisher’s Note: MDPI stays neutral
with regard to jurisdictional claims in
published maps and institutional affil-
iations.
Copyright: © 2021 by the authors.
Licensee MDPI, Basel, Switzerland.
This article is an open access article
distributed under the terms and
conditions of the Creative Commons
Attribution (CC BY) license (https://
creativecommons.org/licenses/by/
4.0/).
Unit of Restorative Dentistry and Endodontics, Department of Medical, Oral and Biotechnological Science,
School of Dentistry, “G. D’Annunzio” University of Chieti, 66100 Chieti, Italy; cdarcang@unich.it (C.D.);
matteo.buonvivere@unich.it (M.B.); rachele.argentino@studenti.unich.it (R.A.); m.vadini@unich.it (M.V.)
*Correspondence: f.deangelis@unich.it; Tel.: +39-(0)85-4549652
Abstract:
Aim of the study is to compare the quality of the apical seal offered by a zinc-eugenol and
a tricalcium-silicate-based sealer, both used with the single-cone or with the continuous wave of
condensation technique. Forty central incisors were divided into four groups (n = 10), according
to the two sealers and the two obturation techniques under investigation, and their outer surface
was isolated with nail varnish. After endodontic treatment, samples were immersed in methylene
blue dye for 72 h, then included in self-curing resin and sectioned to longitudinally expose the
canal apical third. The depth of dye penetration was measured in each group. Mean values were
compared by two-way-ANOVA test. Multiple comparisons were performed by Tukey test. The level
of significance was set at 0.05 in all tests. The continuous wave of condensation technique led to
reduced microleakage. Moreover, dye penetration values were reduced for the tricalcium-silicate
sealer. In terms of microleakage, the warm continuous wave of condensation technique seems
promising even when combined to a bioceramic sealer.
Keywords: bioceramic; continuous wave condensation; microleakage; single-cone; zinc-oxide-eugenol
1. Introduction
The ultimate aim of the root canal treatment, after an adequate disinfection carried out
by mechanical instruments [
1
] and chemical solutions [
2
5
], is to fill in a three-dimensional
way the endodontic space, in order to obtain a fluid-tight barrier, stable over time, with
the purpose of protecting the periradicular tissues from microorganisms present in the
oral cavity.
The most common endodontic filling material is constituted by a combination of a
semi-solid core (gutta-percha) and a fluid sealer [
6
], which have been classically used
following cold gutta-percha techniques (single-cone or lateral condensation) warm com-
paction techniques. In cold obturation techniques, the three-dimensional effectiveness of
the apical seal relies exclusively upon the sealer [
7
,
8
], while in warm techniques a hermetic
apical seal is achieved both owing to the sealer and the heated gutta-percha.
The ideal properties of an effective endodontic sealer were first suggested by Grossman
in 1978 [
9
]. Several sealers have been proposed over time: zinc oxide–eugenol formulations,
calcium hydroxide sealers, glass ionomers, epoxy resin-based, methacrylate resin-based,
and the recently introduced calcium silicate-based sealers [10].
Zinc oxide–eugenol-based sealers are obtained mixing a liquid preparation of eugenol
with a powder containing zinc oxide stably crystallized in a hexagonal wurtzite structure,
as confirmed by X-ray diffraction (XRD) analysis [
11
,
12
]. The setting reaction of zinc
oxide–eugenol is a classical acid–base reaction giving a salt (amorphous chelate of zinc
eugenolate) and water [
13
]. They are widely used in endodontics due to many advantages:
antimicrobial activity [
14
,
15
], resorption in case of extrusion into periradicular tissues [
16
],
and conveniently slow setting time [
17
]. However, they also have some disadvantages:
possible discoloration of tooth structure [
18
], shrinkage on setting [
19
], cytotoxic potential,
Coatings 2021,11, 727. https://doi.org/10.3390/coatings11060727 https://www.mdpi.com/journal/coatings
Coatings 2021,11, 727 2 of 12
and interference with adhesive procedures due to the free eugenol release in tissue fluids
and dental tissues [20,21].
With the recent introduction of calcium silicate-based endodontic sealers, a more
biological approach has taken hold [
22
]. As confirmed by XRD phase observations, these
innovative materials are based on tricalcium silicate, calcium phosphate, zirconium oxide,
and calcium hydroxide [
23
], and hence they are also known as “bioceramics” or “hydraulic
calcium silicate-based sealers” [
24
] or “calcium phosphate-based root canal sealers” [
25
].
Bioceramics raised great interest because of their bioactivity when in contact with tissue
fluids [
22
], their high biocompatibility (with no irritation of periradicular tissues) [
26
],
their slight expansion after setting (which helps to create a hermetic barrier) [
27
], and their
content of calcium phosphate (which allows to create a crystalline structure similar to tooth
and bone apatite materials, improving adhesion to the root dentin) [28].
In some particular situations, such as in presence of widely oval canals or extremely
complex anatomies [
29
], cold gutta-percha techniques have been criticized as they would
hardly allow the complete filling of the whole endodontic space [
30
], while warm obtura-
tion techniques would appear more suitable to achieve a hermetic and three-dimensional
apical seal [
31
]. However, most manufacturers, in agreement with recent literature re-
views [
32
], strongly recommend the use of bioceramics according to the single-cone obtura-
tion technique. Many properties of tricalcium-silicate-based sealers render them particu-
larly suitable to be used in combination with such a technique: they show no shrinkage, no
resorption, and they may undergo some degree of expansion upon setting [
33
]. Several
in vitro
studies [
33
39
] investigated the possible improvement of the apical seal quality
by combining tricalcium-silicate-based root canal sealers to the warm vertical compaction,
but leading to contrasting results. Camilleri [36] keeps on recommending the use of these
type of sealers exclusively with cold obturation techniques; Viapiana at al. [
38
], on the
other hand, claimed the absence of obvious differences when using bioceramic sealers with
cold or warm obturation techniques. Thus, further research seems still required to help
clarifying such an ongoing debate.
On the above bases, the aim of the present
in vitro
study is to compare the extent of
methylene blue dye penetration through the apical foramen following endodontic obturation
procedures performed employing a zinc-eugenol and a bioceramic root canal sealer, in
combination with the single-cone and with the continuous wave of
condensation techniques
.
The null hypotheses to be tested were that there were no statistically significant differences
in terms of microleakage between the tested sealers and between the obturation techniques.
2. Materials and Methods
The present
in vitro
research has been conducted in full accordance with the World
Medical Association Declaration of Helsinki and with the rules of the local ethic committee
of “G. D’Annunzio” University of Chieti, Italy. All human biological materials were
obtained during routine dental procedures, with patients’ agreements. All teeth used
for the experimental procedures were extracted for periodontal reasons and they would
have been extracted anyhow, even if not included in the present investigation: they were
not thrown away but were kept with the aim of being employed for the experimental
procedures, with patients’ agreement.
Forty extracted human upper central incisors (n = 40) were selected. All teeth were
inspected with a stereomicroscope 20
×
(MDG17, Wild Heerbrugg, Heerbrugg, Switzerland)
to detect the presence of caries, open apices, fractures, or resorption areas, that represented
exclusion criteria. The specimens were carefully cleansed with ultrasound to remove
extraneous tissue and calculus, and then stored in an aqueous solution of 0.4% chloramine-
T before the use.
The crowns were horizontally sectioned at the canal entrance level using a cylindrical
diamond bur operated with a high-speed electric handpiece (200,000 rpm) and under abun-
dant irrigation, so that the length of all roots was adjusted to approximately
12 mm
. The
work length was determined by a K-file # 15 (Dentsply Maillefer, Ballaigues, Switzerland)
Coatings 2021,11, 727 3 of 12
introduced in the canal space until the tip was just visible at the apical foramen. Then the
roots were cleaned and shaped with Mtwo rotary system files (Sweden & Martina SpA,
Padova, Italy) alternating each instrument with a profuse irrigation of a 5.25% sodium
hypochlorite (NaOCl) solution. All canals were enlarged to size 50, 0.04 taper, to working
length. After preparation, the canals were irrigated with 5 mL 5.25% NaOCl followed
by 5 mL 17% ethylenediaminetetraacetic acid (EDTA) for 60 s to remove the smear layer.
Successively, the specimens were irrigated with distilled water to avoid the prolonged
effect of the EDTA and NaOCl solutions, then the canals were dried with paper points.
Finally, external surfaces of the roots were coated with three layers of clear nail varnish
except for the apical foramen, which was kept patent by introducing a size 25 k-file in the
apex prior to the application of the nail varnish.
The roots were randomly divided into four groups, according to the root canal sealer
and the obturation technique used.
Information about the endodontic sealers investigated in this study (Figure 1) are
summarized in Table 1.
Coatings 2021, 11, x FOR PEER REVIEW 3 of 12
The crowns were horizontally sectioned at the canal entrance level using a cylindrical
diamond bur operated with a high-speed electric handpiece (200,000 rpm) and under
abundant irrigation, so that the length of all roots was adjusted to approximately 12 mm.
The work length was determined by a K-file # 15 (Dentsply Maillefer, Ballaigues, Switzer-
land) introduced in the canal space until the tip was just visible at the apical foramen.
Then the roots were cleaned and shaped with Mtwo rotary system files (Sweden & Mar-
tina SpA, Padova, Italy) alternating each instrument with a profuse irrigation of a 5.25%
sodium hypochlorite (NaOCl) solution. All canals were enlarged to size 50, 0.04 taper, to
working length. After preparation, the canals were irrigated with 5 mL 5.25% NaOCl fol-
lowed by 5 mL 17% ethylenediaminetetraacetic acid (EDTA) for 60 s to remove the smear
layer. Successively, the specimens were irrigated with distilled water to avoid the pro-
longed effect of the EDTA and NaOCl solutions, then the canals were dried with paper
points. Finally, external surfaces of the roots were coated with three layers of clear nail
varnish except for the apical foramen, which was kept patent by introducing a size 25 k-
file in the apex prior to the application of the nail varnish.
The roots were randomly divided into four groups, according to the root canal sealer
and the obturation technique used.
Information about the endodontic sealers investigated in this study (Figure 1) are
summarized in Table 1.
(a)
(b)
Figure 1. Root canal sealers investigated in the study: (a) zinc-oxide-eugenol-based canal sealer; (b)
tricalcium-silicate-based sealer.
Table 1. Information about the root canal sealers investigated in the study.
Type
Product Name (Man-
ufacturer, Country)
Composition
Zinc-oxide-eugenol-based
sealer
Pulp Canal Sealer
(Kerr, Orange, CA,
USA)
Powder
Liquid
Zinc oxide, precipitated silver, oleoresin, thy-
mol iodide
Oil of cloves, Canada balsam
Tricalcium-silicate-based sealer
BioRoot RCS
(Septodont, Saint-
Maur-des-Fossés,
France)
Powder
Liquid
Tricalcium silicate, zirconium oxide
Aqueous solution of calcium chloride
2.1. Group 1: Zinc-Oxide-Eugenol-Based Canal Sealer and Single-Cone Technique
A single cone of gutta-percha tapered with diameter and conicity corresponding to
the final shaping instrument (# 50.04) was tried in the root canal after visual and tug-back
control. The accuracy of the working-length was assessed by inspecting the tooth through
the apex with a stereomicroscope (20× magnifications) and by periapical radiography. The
canal was dried and the sealer (Pulp Canal Sealer, Kerr, Orange, CA, USA) was mixed
according to the manufacturer’s instructions. Then, the single cone was coated with sealer
and inserted to the working-length with slow movement in order to allow the sealer to
Figure 1.
Root canal sealers investigated in the study: (
a
) zinc-oxide-eugenol-based canal sealer; (
b
) tricalcium-silicate-
based sealer.
Table 1. Information about the root canal sealers investigated in the study.
Type Product Name
(Manufacturer, Country) Composition Lot. No
Zinc-oxide-eugenol-based sealer Pulp Canal Sealer
(Kerr, Orange, CA, USA)
Powder
Liquid
Zinc oxide, precipitated
silver, oleoresin,
thymol iodide
Oil of cloves,
Canada balsam
7,929,829
Tricalcium-silicate-based sealer
BioRoot RCS
(Septodont,
Saint-Maur-des-Fossés, France)
Powder
Liquid
Tricalcium silicate,
zirconium oxide
Aqueous solution of
calcium chloride
B26389
2.1. Group 1: Zinc-Oxide-Eugenol-Based Canal Sealer and Single-Cone Technique
A single cone of gutta-percha tapered with diameter and conicity corresponding to
the final shaping instrument (# 50.04) was tried in the root canal after visual and tug-back
control. The accuracy of the working-length was assessed by inspecting the tooth through
the apex with a stereomicroscope (20
×
magnifications) and by periapical radiography. The
canal was dried and the sealer (Pulp Canal Sealer, Kerr, Orange, CA, USA) was mixed
according to the manufacturer’s instructions. Then, the single cone was coated with sealer
and inserted to the working-length with slow movement in order to allow the sealer to
Coatings 2021,11, 727 4 of 12
flow back coronally and avoid apical extrusion. The coronal excess of gutta-percha was
finally removed with a heated instrument.
2.2. Group 2: Tricalcium-Silicate-Based Sealer and Single-Cone Technique
In this group all the sample preparation procedures were exactly the same as those
described for to the previous group, but a tricalcium-silicate-based sealer (BioRoot RCS,
Septodont SAS, Saint-Maur-des-Fossés, France) was used.
2.3. Group 3: Zinc-Oxide-Eugenol-Based Canal Sealer and Continuous Wave of
Condensation Technique
A master gutta-percha cone tapered with diameter and conicity corresponding to the
final shaping instrument (# 50.04) was selected, then the tip was trimmed with a scalpel
in order to obtain a proper tug-back at 0.5 mm from the working length. The zinc-oxide-
eugenol-based sealer was manipulated with 1:1 proportion according to the manufacturer’s
instructions. After setting the System B (Sybrondental, Orange, CA, USA) temperature at
200
C, a Buchanan plugger was mounted on the device’s handle and inserted at 5 mm
short of the working length without binding on the canal walls; at this level, a rubber
stopper was positioned to mark the coronal reference point. The master cone was then
coated with sealer and fitted into the canal space in order to place the material on the
dentinal walls up to the apical level. Afterwards, the plugger was activated and inserted
into the canal filled with the gutta-percha point until the rubber stopper reached the coronal
reference point. The heat source was deactivated and the plugger was pushed in apical
direction for 10 s with the aim of compensating the gutta-percha shrinkage and allowing
the penetration of the thermoplastic gutta-percha (and eventually of the sealer) in the
accessory canals. The power of the heat source was activated again for 1 s to separate the
plugger from the compacted gutta-percha; then the plugger was extracted and a manual
plugger was immediately inserted to verify the presence of the core material at the apical
level and its adequate compaction [
40
]. Back-filling of the rest of the canal space was
achieved by injecting (Obtura II; Obtura Corporation, Fenton, MO, USA) and compacting
warm gutta-percha with a pre-fitted plugger.
2.4. Group 4: Tricalcium-Silicate-Based Sealer and Continuous Wave of Condensation Technique
In this group the root canal obturation was achieved following the technique described
for Group 3, but the same tricalcium-silicate-based root canal sealer used in Group 2
was employed.
Specimens from every group were stored at 37
C and 100% humidity for 72 h, prior
to be subjected to the subsequent experimental procedures.
After completing the isolation of the root by covering the coronal surface with three
additional layers of nail varnish, the teeth were immersed in an aqueous solution of 2%
methylene blue dye and stored in an incubator, at 37
C for 72 h. Following exposure to
dye, the roots were meticulously rinsed under running water.
The samples were included in self-curing acrylic resin and then put on a coverslip.
The experimental teeth were sectioned longitudinally using a low-speed diamond saw
(Micromet M; Remet S.p.A., Casalecchio di Reno, Italy) in a direction approximately
parallel to the long axis of the tooth and through the apex in order to expose the canal
space. Sectioned samples were placed on a piece of millimetric paper and examined under
a stereomicroscope at 20
×
magnifications. Images were captured and then saved using
a digital device. To estimate the microleakage, the images were imported in a specific
software (Image J version 1.42q; National Institutes of Health, Bethesda, MD, USA) and
analyzed after setting a scale using the millimetric paper on the background of every
sample. The calculation of the microleakage was made by measuring the distance (mm)
between the apical foramen and the most coronal point of dye infiltration.
Means and standard deviations were calculated for each experimental group. The
differences between the means were statistically analyzed by two-way analysis of vari-
ance (ANOVA), in order to assess the effect of the two factors under investigation (the
Coatings 2021,11, 727 5 of 12
“endodontic sealer” and the “obturation technique”) on the microleakage mean values.
Multiple comparisons were performed by a Tukey Test. The level of significance was set at
p< 0.05 in all tests.
After microleakage evaluation, representative samples from every experimental group
were dehydrated in progressive concentrations of ethyl alcohol (70%, 80%, 90%, and 100%)
and sputter-coated with a 300-A
-thick gold layer. They were then observed under a
scanning electron microscope (SEM) (EVO 50 XVP LaB6; Carl Zeiss SMT Ltd., Cambridge,
UK) at 1000
×
and 3500
×
magnification, in order to assess the potential sealer penetration
into the dentinal tubules.
3. Results
The obtained microleakage mean values (and standard deviations), organized accord-
ing to the factors under investigation (endodontic sealer and obturation technique), are
shown in Table 2and graphically depicted in Figure 2.
Table 2.
Mean values (mm) and standard deviations (mm) of the microleakage in each experimental
group organized according to the considered factors: endodontic sealer and obturation technique.
Endodontic Sealer
Obturation Technique
Single Cone Continuous Wave
Zinc-oxide-eugenol-based
sealer (ZOE)
Group 1
3.63 1a(0.82)
Group 3
2.46 2a(1.29)
Tricalcium-silicate-based
sealer (BioRoot)
Group 2
2.33 1b(0.85)
Group 4
1.02 2b(0.60)
a,b
Different superscript letters suggest statistically significant differences in vertical comparisons.
1,2
Different
numbers in pedex suggest statistically significant differences in horizontal comparisons.
Coatings 2021, 11, x FOR PEER REVIEW 5 of 12
Means and standard deviations were calculated for each experimental group. The
differences between the means were statistically analyzed by two-way analysis of vari-
ance (ANOVA), in order to assess the effect of the two factors under investigation (the
“endodontic sealer” and the “obturation technique”) on the microleakage mean values.
Multiple comparisons were performed by a Tukey Test. The level of significance was set
at p < 0.05 in all tests.
After microleakage evaluation, representative samples from every experimental
group were dehydrated in progressive concentrations of ethyl alcohol (70%, 80%, 90%,
and 100%) and sputter-coated with a 300-A°-thick gold layer. They were then observed
under a scanning electron microscope (SEM) (EVO 50 XVP LaB6; Carl Zeiss SMT Ltd.,
Cambridge, UK) at 1000× and 3500× magnification, in order to assess the potential sealer
penetration into the dentinal tubules.
3. Results
The obtained microleakage mean values (and standard deviations), organized ac-
cording to the factors under investigation (endodontic sealer and obturation technique),
are shown in Table 2 and graphically depicted in Figure 2.
Table 2. Mean values (mm) and standard deviations (mm) of the microleakage in each experimental
group organized according to the considered factors: endodontic sealer and obturation technique.
Endodontic Sealer
Obturation Technique
Single Cone
Continuous Wave
Zinc-oxide-eugenol-based sealer (ZOE)
Group 1
3.63 1 a (0.82)
Group 3
2.46 2 a (1.29)
Tricalcium-silicate-based sealer (BioRoot)
Group 2
2.33 1 b (0.85)
Group 4
1.02 2 b (0.60)
a,b Different superscript letters suggest statistically significant differences in vertical comparisons.
1,2 Different numbers in pedex suggest statistically significant differences in horizontal compari-
sons.
Figure 2. Apical microleakage mean values (mm) and standard deviations (mm) of the studied sam-
ples, organized according to the considered factors (endodontic sealer and obturation technique).
3.63 mm
2.46 mm 2.33 mm
1.02 mm
0.00
0.50
1.00
1.50
2.00
2.50
3.00
3.50
4.00
GRUPPO
ZoE-SingleCone ZoE-ContinuousWave
BioRoot-SingleCone BioRoot-ContinuousWave
Figure 2.
Apical microleakage mean values (mm) and standard deviations (mm) of the studied
samples, organized according to the considered factors (endodontic sealer and obturation technique).
The maximum infiltration values (3.63 mm) were observed in Group 1 (zinc-oxide-
eugenol-based sealer and single cone technique), significantly higher compared to all the
other experimental groups.
Coatings 2021,11, 727 6 of 12
The lowest apical microleakage mean values (1.02 mm) were found in Group 4
(tricalcium-silicate-based sealer and the continuous wave of condensation technique),
significantly reduced compared to the remaining experimental conditions tested.
No statistically significant differences were observed when comparing Group 2
(tricalcium-silicate-based sealer and single-cone technique) and Group 3 (zinc-oxide-
eugenol-based canal sealer and continuous wave of condensation technique).
SEM analysis showed an evident penetration of the bioceramic root canal sealer into
the dentinal tubules (Figure 3), whereas in samples obturated with zinc-oxide-eugenol-
based sealer dentinal tubules appeared empty (Figure 4).
Coatings 2021, 11, x FOR PEER REVIEW 6 of 12
The maximum infiltration values (3.63 mm) were observed in Group 1 (zinc-oxide-
eugenol-based sealer and single cone technique), significantly higher compared to all the
other experimental groups.
The lowest apical microleakage mean values (1.02 mm) were found in Group 4 (trical-
cium-silicate-based sealer and the continuous wave of condensation technique), signifi-
cantly reduced compared to the remaining experimental conditions tested.
No statistically significant differences were observed when comparing Group 2
(tricalcium-silicate-based sealer and single-cone technique) and Group 3 (zinc-oxide-eu-
genol-based canal sealer and continuous wave of condensation technique).
SEM analysis showed an evident penetration of the bioceramic root canal sealer into
the dentinal tubules (Figure 3), whereas in samples obturated with zinc-oxide-eugenol-
based sealer dentinal tubules appeared empty (Figure 4).
Figure 3. Scanning electron microphotograph ((A), original magnification 1000×; (B), original magnification 3500×) of a
sample obturated with a bioceramic-based root canal sealer and warm vertical condensation. Sealer penetration into the
dentinal tubules may be observed (arrows).
Figure 4. Scanning electron microphotograph ((A), original magnification 1000×; (B), original magnification 3500×) of a
sample obturated with zinc-oxide-eugenol-based root canal sealer and warm vertical condensation. Dentinal tubules ap-
pear empty.
4. Discussion
The null hypotheses tested in the present study had to be rejected: there were statis-
tically significant differences in terms of microleakage between the tested sealers and ob-
turation techniques.
Figure 3.
Scanning electron microphotograph ((
A
), original magnification 1000
×
; (
B
), original magnification 3500
×
) of a
sample obturated with a bioceramic-based root canal sealer and warm vertical condensation. Sealer penetration into the
dentinal tubules may be observed (arrows).
Coatings 2021, 11, x FOR PEER REVIEW 6 of 12
The maximum infiltration values (3.63 mm) were observed in Group 1 (zinc-oxide-
eugenol-based sealer and single cone technique), significantly higher compared to all the
other experimental groups.
The lowest apical microleakage mean values (1.02 mm) were found in Group 4 (trical-
cium-silicate-based sealer and the continuous wave of condensation technique), signifi-
cantly reduced compared to the remaining experimental conditions tested.
No statistically significant differences were observed when comparing Group 2
(tricalcium-silicate-based sealer and single-cone technique) and Group 3 (zinc-oxide-eu-
genol-based canal sealer and continuous wave of condensation technique).
SEM analysis showed an evident penetration of the bioceramic root canal sealer into
the dentinal tubules (Figure 3), whereas in samples obturated with zinc-oxide-eugenol-
based sealer dentinal tubules appeared empty (Figure 4).
Figure 3. Scanning electron microphotograph ((A), original magnification 1000×; (B), original magnification 3500×) of a
sample obturated with a bioceramic-based root canal sealer and warm vertical condensation. Sealer penetration into the
dentinal tubules may be observed (arrows).
Figure 4. Scanning electron microphotograph ((A), original magnification 1000×; (B), original magnification 3500×) of a
sample obturated with zinc-oxide-eugenol-based root canal sealer and warm vertical condensation. Dentinal tubules ap-
pear empty.
4. Discussion
The null hypotheses tested in the present study had to be rejected: there were statis-
tically significant differences in terms of microleakage between the tested sealers and ob-
turation techniques.
Figure 4.
Scanning electron microphotograph ((
A
), original magnification 1000
×
; (
B
), original magnification 3500
×
) of
a sample obturated with zinc-oxide-eugenol-based root canal sealer and warm vertical condensation. Dentinal tubules
appear empty.
4. Discussion
The null hypotheses tested in the present study had to be rejected: there were sta-
tistically significant differences in terms of microleakage between the tested sealers and
obturation techniques.
Coatings 2021,11, 727 7 of 12
Several methods have been proposed in the literature to investigate microleakage:
Fluid filtration or transportation method, which consists in measuring an air bubble move-
ment within a capillary tube [
41
,
42
]; dye extraction or dissolution method, in which the
teeth are dissolved in acids to release the dye from the interfacial areas and obtain a solution
whose optical density is determined with a spectrophotometer [
41
]; bacteria and toxin
infiltration method, a qualitative evaluation whereby penetration of bacterial organisms is
estimated [
43
]; glucose penetration model, which relies on the assessment of the filtration
rate of glucose along the root canal obturation material [
44
,
45
]; protein microleakage test,
that is performed using bovine serum albumin in a dual-chamber apparatus and estimated
using a spectrophotometer [
46
,
47
]; electrochemical microleakage method, which consists
in the diffusion of ions through narrow spaces [
48
]; three-dimensional methods carried out
using cone-beam computed tomography (CBCT) [
49
] and SEM evaluations [
50
]; dye pene-
tration methods, in which teeth are immersed in various types of dyes and then sectioned
(longitudinally or transversely) or cleared to record linear penetration of the dye [
43
,
51
]. To
date, there is still some debate about the most reliable method for investigating the apical
microleakage in endodontics. In this study, the dye penetration method was preferred
because of its relative simplicity and easy replicability.
In the present research, the highest dye infiltration values were observed in samples
from Group 1, probably because they combined the intrinsic limits of both a conventional
sealer and a cold compaction technique. Among the main disadvantages of a single-cone
technique, the lack of a sufficiently homogeneous obturation has been often underlined,
together with the reduced chance of filling every void, which ultimately provide an apical
seal whose predictability ends up relying just on the specific properties of the endodontic
sealer. Clinically, this could represent a limit in case of resorbable sealers [
7
,
8
]. In Group 1, a
conventional zinc-oxide-eugenol-based canal sealer was used: based on previous research,
such a material shows a certain degree of shrinkage after setting [
19
], which might lead
to the generation of voids. In Group 2, a tricalcium-silicate-based sealer was used in
combination with the single-cone technique and the dye penetration turned out to be
significantly lower than in Group 1. Tricalcium-silicate sealers have the ability to undergo
a slight expansion after setting [
27
], which probably helped increasing the tightness of the
apical seal even if combined with a particularly inefficient obturation strategy. The present
results would support the wide-spread habit of employing bioceramic sealers together
with a single cold gutta-percha cone [
52
], as the many limitations of such an extremely
simplified obturation technique seem to be overcome owing to the advantageous properties
of those innovative materials.
Tricalcium-silicate-based sealers seem to positively interact with dentin fluid, poten-
tially inducing biomineralization with the formation of mineral tags within the dentinal
tubules, thus enhancing the biological activity within the root canal [
53
], due to the pres-
ence of calcium phosphate in their composition that enhances the setting mechanism [
28
]
and improves the chemical bonding between the sealer and the root dentin [
26
]. Calcium
phosphate is also the main reason for the outstanding bioceramic’s biocompatibility, that
is their ability to not trigger adverse reaction when in contact with tissues [
28
]. Calcium
phosphate is, in fact, one of the major inorganic constituents of hard tissues. Indeed, it
has been shown that these materials can even promote bone regeneration [
54
] when acci-
dentally extruded through the apical foramen during root canal filling procedures [
55
,
56
].
These materials have also the ability to establish a micromechanical retention by tag sealer
penetration in dentinal tubules [
57
]. In the present study, the scanning electron microscope
analysis confirmed a visible penetration of the bioceramic root canal sealer into the denti-
nal tubules: this behavior may help establishing a stronger physical barrier, improving
retention of the root filling, entombing possible residual bacteria into dentinal tubules
and, probably, enhancing the ultimate quality of the apical seal [
35
]. Among the other
interesting properties of bioceramic-based sealers, the following should be underlined:
An adequate setting time [
26
,
58
,
59
]; a reduced risk of discoloration of tooth structures
when compared with other conventional root canal sealers [
26
]; a high radiopacity due to
Coatings 2021,11, 727 8 of 12
the presence of bismuth trioxide [
60
,
61
]; an antimicrobial activity, owing to the high pH
values and the high tendency to release calcium ions [
62
,
63
]. Of course, these materials
are not completely free from possible shortcomings: a major drawback is their complex
removal in case of orthograde endodontic retreatments [
64
]. Moreover, endodontically
treated teeth may often benefit from the use of adhesively luted fiber-post to effectively
support the coronal restoration [
65
70
] but a thorough cleaning of the root canal walls,
which is required for an appropriate post-space preparation, might become definitely
challenging when a bioceramic sealer is used [
64
]. Finally, some doubts seem to come from
a few studies that showed how certain properties of bioceramics, such as flow [
62
,
71
,
72
] or
solubility [73,74], do not steadily fulfil the ISO standard requirements.
In Group 3, the zinc-oxide-eugenol-based canal sealer was used together with the
continuous wave of condensation technique and the microleakage results were comparable
to Group 2, again significantly enhanced compared to Group 1. In this case, the improved
performances can be explained owing to the advantages of the continuous wave of conden-
sation, which typically lead to a denser and more homogeneous filling and allow a better
sealing [
7
,
75
], in presence of less voids, when compared to cold obturation techniques [
76
].
The use of warm gutta-percha allows to fill even the endodontic areas of challenging access,
due to the reduced viscosity and owing to the vertical compaction loads.
In Group 4 (tricalcium-silicate-based sealer and continuous wave of condensation
technique), the dye penetration values were the lowest among all the experimental groups.
According to these authors, such a finding could be explained taking into account the
combined benefits coming from both the warm obturation technique and the advantageous
properties of the bioceramic-based sealer.
5. Conclusions
As previously mentioned, the current literature is not unanimous when dealing with
the association of a bioceramic-based sealer to a warm obturation techniques. Qu et al. [
37
]
showed that after heat application, bioceramic-based root canal sealer exhibited a reduction
in setting time and flow, which could negatively influence the performance of obturation
and the procedure outcome. Camilleri et al. [
36
] observed how the material chemistry
and the physical properties were not affected by the heat, but still suggested to follow the
guidelines of the manufacturers, which recommend the use of a single cone technique.
Other studies [
33
35
] affirmed that the obturation technique does not affect the efficacy
of the bioceramic sealers. Hadis et al. [
39
] compared a new bioceramic-based root canal
sealer, designed to be used with a warm obturation technique, with one recommended
for the single cone technique; the results showed no differences between the two sealers,
when they were used following a warm filling technique. Viapiana et al. [
38
] observed
bioceramic sealers to be stable even when used with a warm vertical compaction, but
they also underlined the need for a better investigation about the effect of heat on sealer
properties. Atmeh et al. [
77
] claimed that even if heat does not cause changes in the
bioceramic chemical structure, it seems to produce some microstructural changes due to
water loss. Specifically, a Fourier-transformed infrared spectroscopy (FT-IR) analysis of an
heated bioceramic sealer revealed a drop in the peaks representing vibrational modes of
the OH group in water, thus proving an irreversible water loss above 100
C by means of
evaporation [78].
Within the limits of the present study, it seems that in terms of microleakage of recently
sealed samples a warm obturation technique is promising even when used in association
with a tricalcium-silicate root canal sealer. However, it must be underlined that no attempt
was made herein to artificially simulate any effect of specimen aging. Thus, the long-
term stability of the apical seal obtained with tricalcium-silicate-based sealers subjected
to heat sources should be still verified, and it could represent an interesting subject for
further research.
Based on the results of the present study, the following conclusions can be drawn:
Coatings 2021,11, 727 9 of 12
The obturation technique is a factor able to significantly affect the quality of the apical
seal in terms of microleakage and the dye penetration is reduced with a warm wave
of condensation technique, compared to a cold single-cone obturation technique;
Obturation technique being equal, tricalcium-silicate-based root canal sealers appear
to be more performing than conventional zinc-eugenol-based sealers;
In terms of microleakage, warm obturation techniques seem promising even when
used in combination with a tricalcium-silicate-based root canal sealer.
Author Contributions:
Conceptualization, C.D., F.D.A. and M.V.; data curation, C.D., F.D.A. and
M.V.; formal analysis, F.D.A.; investigation, F.D.A., M.B. and R.A.; methodology, F.D.A. and M.B.;
project administration, C.D. and M.V.; resources, F.D.A. and C.D.; supervision, F.D.A., C.D. and
M.V.; validation, C.D.; visualization, F.D.A. and M.B.; writing—original draft, F.D.A., M.B. and R.A.;
writing—review and editing, F.D.A., M.B. and R.A. All authors have read and agreed to the published
version of the manuscript.
Funding: This research received no external funding.
Institutional Review Board Statement: Not applicable.
Informed Consent Statement: Not applicable.
Data Availability Statement:
The data presented in this study are available on request from the
corresponding author.
Conflicts of Interest: The authors declare no conflict of interest.
References
1.
D’Amario, M.; Baldi, M.; Petricca, R.; De Angelis, F.; El Abed, R.; D’Arcangelo, C. Evaluation of a new nickel-titanium system to
create the glide path in root canal preparation of curved canals. J. Endod. 2013,39, 1581–1584. [CrossRef]
2.
D’Arcangelo, C.; Di Nardo Di Maio, F.; Stracci, N.; Spoto, G.; Malagnino, V.A.; Caputi, S. Pulp-Dissolving ability of several
endodontic irrigants: A spectrophotometric evaluation. Int. J. Immunopathol. Pharmacol. 2007,20, 381–386. [CrossRef]
3.
D’Arcangelo, C.; Varvara, G.; De Fazio, P. An evaluation of the action of different root canal irrigants on facultative aerobic-
anaerobic, obligate anaerobic, and microaerophilic bacteria. J. Endod. 1999,25, 351–353. [CrossRef]
4.
Petrini, M.; Spoto, G.; Scarano, A.; D’Arcangelo, C.; Tripodi, D.; Di Fermo, P.; D’Ercole, S. Near-Infrared LEDS provide persistent
and increasing protection against E. faecalis.J. Photochem. Photobiol. B Biol. 2019,197, 111527. [CrossRef]
5. D’Amario, M.; De Angelis, F.; Mancino, M.; Frascaria, M.; Capogreco, M.; D’Arcangelo, C. Canal shaping of different single-file
systems in curved root canals. J. Dent. Sci. 2017,12, 328–332. [CrossRef]
6.
Tomson, R.M.; Polycarpou, N.; Tomson, P.L. Contemporary obturation of the root canal system. Br. Dent. J.
2014
,216, 315–322.
[CrossRef] [PubMed]
7.
Peng, L.; Ye, L.; Tan, H.; Zhou, X. Outcome of root canal obturation by warm gutta-percha versus cold lateral condensation: A
meta-analysis. J. Endod. 2007,33, 106–109. [CrossRef] [PubMed]
8.
Peters, D.D. Two-Year
in vitro
solubility evaluation of four Gutta-percha sealer obturation techniques. J. Endod.
1986
,12, 139–145.
[CrossRef]
9.
Fonseca, D.A.; Paula, A.B.; Marto, C.M.; Coelho, A.; Paulo, S.; Martinho, J.P.; Carrilho, E.; Ferreira, M.M. Biocompatibility of root
canal sealers: A systematic review of in vitro and in vivo studies. Materials 2019,12, 4113. [CrossRef] [PubMed]
10.
Colombo, M.; Poggio, C.; Dagna, A.; Meravini, M.V.; Riva, P.; Trovati, F.; Pietrocola, G. Biological and physico-chemical properties
of new root canal sealers. J. Clin. Exp. Dent. 2018,10, e120–e126. [CrossRef]
11.
Bakhori, S.K.M.; Mahmud, S.; Mohamad, D.; Masudi, S.M.; Seeni, A. Surface morphological and mechanical properties of zinc
oxide eugenol using different types of ZnO nanopowder. Mater. Sci. Eng. C Mater. Biol. Appl.
2019
,100, 645–654. [CrossRef]
[PubMed]
12.
Javidi, M.; Zarei, M.; Naghavi, N.; Mortazavi, M.; Nejat, A.H. Zinc oxide nano-particles as sealer in endodontics and its sealing
ability. Contemp. Clin. Dent. 2014,5, 20–24. [CrossRef]
13.
Crisp, S.; Ambersley, M.; Wilson, A.D. Zinc oxide eugenol cements. V. Instrumental studies of the catalysis and acceleration of the
setting reaction. J. Dent. Res. 1980,59, 44–54. [CrossRef] [PubMed]
14.
Mickel, A.K.; Nguyen, T.H.; Chogle, S. Antimicrobial activity of endodontic sealers on Enterococcus faecalis.J. Endod.
2003
,29,
257–258. [CrossRef]
15.
Komabayashi, T.; Colmenar, D.; Cvach, N.; Bhat, A.; Primus, C.; Imai, Y. Comprehensive review of current endodontic sealers.
Dent. Mater. J. 2020,39, 703–720. [CrossRef] [PubMed]
16.
Giacomino, C.M.; Wealleans, J.A.; Kuhn, N.; Diogenes, A. Comparative Biocompatibility and osteogenic potential of two
bioceramic sealers. J. Endod. 2019,45, 51–56. [CrossRef]
Coatings 2021,11, 727 10 of 12
17.
Allan, N.A.; Walton, R.C.; Schaeffer, M.A. Setting times for endodontic sealers under clinical usage and
in vitro
conditions. J.
Endod. 2001,27, 421–423. [CrossRef]
18. Davis, M.C.; Walton, R.E.; Rivera, E.M. Sealer distribution in coronal dentin. J. Endod. 2002,28, 464–466. [CrossRef]
19.
Kazemi, R.B.; Safavi, K.E.; Spångberg, L.S. Dimensional changes of endodontic sealers. Oral Surg. Oral Med. Oral Pathol.
1993
,76,
766–771. [CrossRef]
20.
Mosharraf, R.; Zare, S. Effect of the type of endodontic sealer on the bond strength between fiber post and root wall dentin. J.
Dent. 2014,11, 455–463.
21.
Altmann, A.S.; Leitune, V.C.; Collares, F.M. Influence of eugenol-based sealers on push-out bond strength of fiber post luted with
resin cement: Systematic review and meta-analysis. J. Endod. 2015,41, 1418–1423. [CrossRef] [PubMed]
22. Khalil, I.; Naaman, A.; Camilleri, J. Properties of tricalcium silicate sealers. J. Endod. 2016,42, 1529–1535. [CrossRef] [PubMed]
23.
Xuereb, M.; Vella, P.; Damidot, D.; Sammut, C.V.; Camilleri, J. In situ assessment of the setting of tricalcium silicate-based sealers
using a dentin pressure model. J. Endod. 2015,41, 111–124. [CrossRef]
24.
Kebudi Benezra, M.; Schembri Wismayer, P.; Camilleri, J. Interfacial characteristics and cytocompatibility of hydraulic sealer
cements. J. Endod. 2018,44, 1007–1017. [CrossRef]
25.
Krell, K.F.; Wefel, J.S. A calcium phosphate cement root canal sealer-scanning electron microscopic analysis. J. Endod.
1984
,10,
571–576. [CrossRef]
26.
Al-Haddad, A.; Che Ab Aziz, Z.A. Bioceramic-Based root canal sealers: A review. Int. J. Biomater.
2016
,2016, 9753210. [CrossRef]
27.
Berman, L.H.; Hargreaves, K.M. Cohen’s Pathways of the Pulp Expert Consult; Elsevier Health Sciences: Amsterdam, The Nether-
lands, 2015.
28.
Prati, C.; Gandolfi, M.G. Calcium silicate bioactive cements: Biological perspectives and clinical applications. Dent. Mater. Off.
Publ. Acad. Dent. Mater. 2015,31, 351–370. [CrossRef]
29.
D’Arcangelo, C.; Varvara, G.; De Fazio, P. Root canal treatment in mandibular canines with two roots: A report of two cases. Int.
Endod. J. 2001,34, 331–334. [CrossRef]
30.
Celikten, B.; Uzuntas, C.F.; Orhan, A.I.; Orhan, K.; Tufenkci, P.; Kursun, S.; Demiralp, K. 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, 133–140. [CrossRef]
31. Schilder, H. Filling root canals in three dimensions. Dent. Clin. N. Am. 1967, 723–744. [CrossRef]
32.
Lim, M.; Jung, C.; Shin, D.H.; Cho, Y.B.; Song, M. Calcium silicate-based root canal sealers: A literature review. Restor. Dent.
Endod. 2020,45, e35. [CrossRef]
33.
Al-Hiyasat, A.S.; Alfirjani, S.A. The effect of obturation techniques on the push-out bond strength of a premixed bioceramic root
canal sealer. J. Dent. 2019,89, 103169. [CrossRef]
34.
Reynolds, J.Z.; Augsburger, R.A.; Svoboda, K.K.H.; Jalali, P. Comparing dentinal tubule penetration of conventional and ‘HiFlow’
bioceramic sealers with resin-based sealer: An in vitro study. Aust. Endod. J. 2020,46, 387–393. [CrossRef]
35.
McMichael, G.E.; Primus, C.M.; Opperman, L.A. Dentinal tubule penetration of tricalcium silicate sealers. J. Endod.
2016
,42,
632–636. [CrossRef]
36. Camilleri, J. Sealers and warm gutta-percha obturation techniques. J. Endod. 2015,41, 72–78. [CrossRef]
37.
Qu, W.; Bai, W.; Liang, Y.H.; Gao, X.J. Influence of warm vertical compaction technique on physical properties of root canal
sealers. J. Endod. 2016,42, 1829–1833. [CrossRef]
38.
Viapiana, R.; Baluci, C.A.; Tanomaru-Filho, M.; Camilleri, J. Investigation of chemical changes in sealers during application of the
warm vertical compaction technique. Int. Endod. J. 2015,48, 16–27. [CrossRef] [PubMed]
39.
Hadis, M.; Camilleri, J. Characterization of heat resistant hydraulic sealer for warm vertical obturation. Dent. Mater. Off. Publ.
Acad. Dent. Mater. 2020,36, 1183–1189. [CrossRef] [PubMed]
40.
Angerame, D.; De Biasi, M.; Pecci, R.; Bedini, R.; Tommasin, E.; Marigo, L.; Somma, F. Analysis of single point and continuous
wave of condensation root filling techniques by micro-computed tomography. Ann. Ist. Super. Sanita
2012
,48, 35–41. [CrossRef]
[PubMed]
41.
Veríssimo, D.M.; do Vale, M.S. Methodologies for assessment of apical and coronal leakage of endodontic filling materials: A
critical review. J. Oral Sci. 2006,48, 93–98. [CrossRef]
42.
Agrafioti, A.; Tzimpoulas, N.; Chatzitheodoridis, E.; Kontakiotis, E.G. Comparative evaluation of sealing ability and microstruc-
ture of MTA and Biodentine after exposure to different environments. Clin. Oral. Investig. 2016,20, 1535–1540. [CrossRef]
43.
Jafari, F.; Jafari, S. Importance and methodologies of endodontic microleakage studies: A systematic review. J. Clin. Exp. Dent.
2017,9, e812–e819. [CrossRef]
44.
Kim, S.Y.; Ahn, J.S.; Yi, Y.A.; Lee, Y.; Hwang, J.Y.; Seo, D.G. Quantitative microleakage analysis of endodontic temporary filling
materials using a glucose penetration model. Acta Odontol. Scand. 2015,73, 137–143. [CrossRef] [PubMed]
45.
Leal, F.; De-Deus, G.; Brandão, C.; Luna, A.; Souza, E.; Fidel, S. Similar sealability between bioceramic putty ready-to-use repair
cement and white MTA. Braz. Dent. J. 2013,24, 362–366. [CrossRef]
46.
Shahi, S.; Rahimi, S.; Hasan, M.; Shiezadeh, V.; Abdolrahimi, M. Sealing ability of mineral trioxide aggregate and Portland cement
for furcal perforation repair: A protein leakage study. J. Oral Sci. 2009,51, 601–606. [CrossRef] [PubMed]
47.
Zarenejad, N.; Asgary, S.; Ramazani, N.; Haghshenas, M.R.; Rafiei, A.; Ramazani, M. Coronal microleakage of three different
dental biomaterials as intra-orifice barrier during nonvital bleaching. Dent. Res. J. 2015,12, 581–588. [CrossRef]
Coatings 2021,11, 727 11 of 12
48.
Pommel, L.; Jacquot, B.; Camps, J. Lack of correlation among three methods for evaluation of apical leakage. J. Endod.
2001
,27,
347–350. [CrossRef]
49.
Gupta, R.; Dhingra, A.; Panwar, N.R. Comparative evaluation of three different obturating techniques lateral compaction,
thermafil and calamus for filling area and voids using cone beam computed tomography: An
in vitro
study. J. Clin. Diagn. Res.
2015,9, ZC15–ZC17. [CrossRef]
50.
Moura-Netto, C.; Guglielmi Cde, A.; Mello-Moura, A.C.; Palo, R.M.; Raggio, D.P.; Caldeira, C.L. Nd: YAG laser irradiation effect
on apical intracanal dentin—A microleakage and SEM evaluation. Braz. Dent. J. 2011,22, 377–381. [CrossRef]
51.
Zmener, O.; Pameijer, C.H.; Macri, E. Evaluation of the apical seal in root canals prepared with a new rotary system and obturated
with a methacrylate based endodontic sealer: An in vitro study. J. Endod. 2005,31, 392–395. [CrossRef]
52.
Garrib, M.; Camilleri, J. Retreatment efficacy of hydraulic calcium silicate sealers used in single cone obturation. J. Dent.
2020
,98,
103370. [CrossRef]
53.
Reyes-Carmona, J.F.; Felippe, M.S.; Felippe, W.T. A phosphate-buffered saline intracanal dressing improves the biomineralization
ability of mineral trioxide aggregate apical plugs. J. Endod. 2010,36, 1648–1652. [CrossRef]
54.
D’Arcangelo, C.; D’Amario, M. Use of MTA for orthograde obturation of nonvital teeth with open apices: Report of two cases.
Oral Surg. Oral Med. Oral Pathol. Oral Radiol. Endod. 2007,104, e98–e101. [CrossRef] [PubMed]
55.
Bae, W.J.; Chang, S.W.; Lee, S.I.; Kum, K.Y.; Bae, K.S.; Kim, E.C. Human periodontal ligament cell response to a newly developed
calcium phosphate-based root canal sealer. J. Endod. 2010,36, 1658–1663. [CrossRef]
56.
Bryan, T.E.; Khechen, K.; Brackett, M.G.; Messer, R.L.; El-Awady, A.; Primus, C.M.; Gutmann, J.L.; Tay, F.R.
In vitro
osteogenic
potential of an experimental calcium silicate-based root canal sealer. J. Endod. 2010,36, 1163–1169. [CrossRef]
57.
Marissa, C.; Usman, M.; Suprastiwi, E.; Erdiani, A.; Meidyawati, R. Comparison of dentinal tubular penetration of three
bioceramic sealers. Int. J. Appl. Pharm. 2020,12, 23–26. [CrossRef]
58.
Hosoya, N.; Nomura, M.; Yoshikubo, A.; Arai, T.; Nakamura, J.; Cox, C.F. Effect of canal drying methods on the apical seal. J.
Endod. 2000,26, 292–294. [CrossRef] [PubMed]
59.
Paqué, F.; Luder, H.U.; Sener, B.; Zehnder, M. Tubular sclerosis rather than the smear layer impedes dye penetration into the
dentine of endodontically instrumented root canals. Int. Endod. J. 2006,39, 18–25. [CrossRef] [PubMed]
60.
Guerreiro-Tanomaru, J.M.; Duarte, M.A.; Gonçalves, M.; Tanomaru-Filho, M. Radiopacity evaluation of root canal sealers
containing calcium hydroxide and MTA. Braz. Oral Res. 2009,23, 119–123. [CrossRef]
61.
Imai, Y.; Komabayashi, T. Properties of a new injectable type of root canal filling resin with adhesiveness to dentin. J. Endod.
2003
,
29, 20–23. [CrossRef]
62.
Candeiro, G.T.; Correia, F.C.; Duarte, M.A.; Ribeiro-Siqueira, D.C.; Gavini, G. Evaluation of radiopacity, pH, release of calcium
ions, and flow of a bioceramic root canal sealer. J. Endod. 2012,38, 842–845. [CrossRef]
63.
Morgental, R.D.; Vier-Pelisser, F.V.; Oliveira, S.D.; Antunes, F.C.; Cogo, D.M.; Kopper, P.M. Antibacterial activity of two MTA-based
root canal sealers. Int. Endod. J. 2011,44, 1128–1133. [CrossRef]
64.
Cherng, A.M.; Chow, L.C.; Takagi, S.
In vitro
evaluation of a calcium phosphate cement root canal filler/sealer. J. Endod.
2001
,27,
613–615. [CrossRef] [PubMed]
65.
Marigo, L.; D’Arcangelo, C.; De Angelis, F.; Cordaro, M.; Vadini, M.; Lajolo, C. Evaluation of
in vitro
push-out bond strengths of
different post-luting systems after artificial aging. Minerva Stomatol. 2017,66, 20–27. [CrossRef] [PubMed]
66.
D’Arcangelo, C.; D’Amario, M.; Vadini, M.; Zazzeroni, S.; De Angelis, F.; Caputi, S. An evaluation of luting agent application
technique effect on fibre post retention. J. Dent. 2008,36, 235–240. [CrossRef]
67.
D’Arcangelo, C.; Zazzeroni, S.; D’Amario, M.; Vadini, M.; De Angelis, F.; Trubiani, O.; Caputi, S. Bond strengths of three types of
fibre-reinforced post systems in various regions of root canals. Int. Endod. J. 2008,41, 322–328. [CrossRef]
68.
D’Arcangelo, C.; D’Amario, M.; De Angelis, F.; Zazzeroni, S.; Vadini, M.; Caputi, S. Effect of application technique of luting agent
on the retention of three types of fiber-reinforced post systems. J. Endod. 2007,33, 1378–1382. [CrossRef]
69.
D’Arcangelo, C.; Cinelli, M.; De Angelis, F.; D’Amario, M. The effect of resin cement film thickness on the pullout strength of a
fiber-reinforced post system. J. Prosthet. Dent. 2007,98, 193–198. [CrossRef]
70.
D’Arcangelo, C.; D’Amario, M.; Vadini, M.; De Angelis, F.; Caputi, S. Influence of surface treatments on the flexural properties of
fiber posts. J. Endod. 2007,33, 864–867. [CrossRef]
71.
Zhou, H.M.; Shen, Y.; Zheng, W.; Li, L.; Zheng, Y.F.; Haapasalo, M. Physical properties of 5 root canal sealers. J. Endod.
2013
,39,
1281–1286. [CrossRef]
72.
Vitti, R.P.; Prati, C.; Silva, E.J.; Sinhoreti, M.A.; Zanchi, C.H.; de Souza e Silva, M.G.; Ogliari, F.A.; Piva, E.; Gandolfi, M.G. Physical
properties of MTA Fillapex sealer. J. Endod. 2013,39, 915–918. [CrossRef]
73.
Borges, R.P.; Sousa-Neto, M.D.; Versiani, M.A.; Rached-Júnior, F.A.; De-Deus, G.; Miranda, C.E.; Pécora, J.D. Changes in the
surface of four calcium silicate-containing endodontic materials and an epoxy resin-based sealer after a solubility test. Int. Endod.
J. 2012,45, 419–428. [CrossRef]
74.
Viapiana, R.; Flumignan, D.L.; Guerreiro-Tanomaru, J.M.; Camilleri, J.; Tanomaru-Filho, M. Physicochemical and mechanical
properties of zirconium oxide and niobium oxide modified Portland cement-based experimental endodontic sealers. Int. Endod. J.
2014,47, 437–448. [CrossRef]
75.
Gilbert, S.D.; Witherspoon, D.E.; Berry, C.W. Coronal leakage following three obturation techniques. Int. Endod. J.
2001
,34,
293–299. [CrossRef]
Coatings 2021,11, 727 12 of 12
76.
Kele¸s, A.; Keskin, C. Presence of voids after warm vertical compaction and single-cone obturation in band-shaped isthmuses
using micro-computed tomography: A phantom study. Microsc. Res. Tech. 2020,83, 370–374. [CrossRef]
77.
Atmeh, A.R.; AlShwaimi, E. The effect of heating time and temperature on epoxy resin and calcium silicate-based endodontic
sealers. J. Endod. 2017,43, 2112–2118. [CrossRef]
78.
Atmeh, A.R.; Hadis, M.; Camilleri, J. Real-Time chemical analysis of root filling materials with heating: Guidelines for safe
temperature levels. Int. Endod. J. 2020,53, 698–708. [CrossRef]
... Most commonly used are cold obturation techniques and warm vertical compaction techniques. A tight apical seal is achieved by using warm obturation techniques, but whereas in cold obturation techniques, it is fully dependent on the root canal sealer [2]. ...
... A more biological approach has gained traction in recent years with the development of Tricalcium Silicate-Based Root Canal Sealers because of their excellent biocompatibility with modest expansion after setting, it improves adherence to root dentin [2]. ...
... Although GP is a root canal filling material of the highest calibre, it alone cannot achieve the proper adaptation to the root canal system leaving voids. sealers are used in conjunction with GP to provide three -dimensional hermetic seal [2]. ...
... This technique usually exhibits cohesive failure within the thin sealer film [29]. It has been reported that the single-cone technique shows greater leakage than the continuous wave technique [43]. This may be attributed to the relatively large sealer volume associated with the single-cone technique, which encourages the development of voids within the sealer layers [44,45]. ...
Article
Full-text available
This study compared the push-out bond strength and adaptation of the recently developed AH Plus bioceramic (AHP-Bio) root canal sealer with Bioceramic Endosequence (BC) and AH Plus (AHP) sealers when exposed to simulated body fluid for inducing bioactivity. Cross-section discs of 1 mm thick slices from obturated root canals were prepared and either kept dry or immersed in serum for 30 days. All discs were evaluated using scanning electron microscopy (SEM) and then subjected to a push-out test. The failure modes were also determined. The data were statistically analyzed using an ANOVA test at p < 0.05. In both environments, the BC sealer recorded the greatest bond strength, while the AHP-Bio sealer recorded the lowest mean values. However, bond strength was significantly improved after immersion in serum (p < 0.001). The chi-square test and Fisher’s exact test revealed a significant difference in failure mode among the tested groups at p < 0.001. The predominant failure mode was cohesive failure in both bioceramic sealers, with the greatest value for AHP-Bio (70%), and adhesive failure for AHP/gutta-percha (60%, 80%) in both environments. SEM revealed good dentin adaptation of the three sealers, with marked decreases in gaps at the bioceramic/dentin interface after immersion in serum. In conclusion, although BC exhibited greater push-out bond strength than AHP-Bio, the latter achieved good displacement resistance that increased when the sealer was exposed to simulated body fluid (serum).
... За різними дослідженнями, надлишкова кількість силера та апікальні пори можуть впливати на герметичність. Для визначення проникності в апікальній частині та якості пломбування застосовувались різні види тестів [8,9]. Ще однією поширеною причиною невдачі ендодонтичного лікування є порушення гирлової герметизації [10]. ...
Article
Мета дослідження: провести порівняння якості апікальної герметизації кореневих каналів перших верхніх молярів при диференційованому та традиційному підході до обробки апікальної частини кореневого каналу, з обтурацією методом холодної латеральної конденсації та використанням цинк-оксид-евгенольних силерів та силерів на основі епоксидних смол, а також визначити проникливість у гирловій частині кореневих каналів після обтурації із додатковою герметизацією гирл склоіономерним цементом та без неї. Матеріали та методи дослідження: для дослідження було використано видалені зуби, а саме перші верхні моляри без попереднього ендодонтичного втручання. Проведено ендодонтичну підготовку за запропонованою та традиційною методикою, пломбування каналів з використанням цинк-оксид-евгенольного силера та силера на основі епоксидних смол. Окрім цього, в одній із груп зубів було проведена додаткова герметизація гирл кореневих каналів за допомогою склоіономерного цементу. Оцінку герметизації апікальної частини каналу проводили на поперечних шліфах коренів, які були зроблені на відстані від 1 до 5 мм від верхівки. Після чого на знімках за допомогою програми ImageJ визначали площу зафарбованої поверхні. Проводили також секторальне визначення апікального проникнення барвника. Для визначення глибини проникнення барвника в гирловій частині було проведено повздовжні шліфи на кожному з коренів перших верхніх молярів та зроблені цифрові зображення, з подальшим аналізом в програмі ImageJ. Наукова новизна. У ході проведення лабораторного визначення стану апікальної та коронкової герметизації кореневих каналів перших верхніх молярів, виявлено, що при використанні запропонованої методики обробки кореневих каналів глибина апікального проникнення барвника є достовірно нижчою, порівняно з традиційною методикою Також площа зафарбовування та % проникнення барвника є нижчими у даній групі. Висновки. Встановлено, що ефективність герметизації залежить від анатомічної форми каналу та способу його обробки. Виявлено, що при проведені додаткової герметизації гирлової частини кореневих каналів СІЦ глибина проникнення барвника є значно нижчою, ніж при відсутності герметизації.
... After reading the full texts, a total of 16 articles were selected for. Out of these articles, 6 articles did not satisfy the inclusion criteria, because three articles evaluated different endodontic sealers for both evaluated techniques (2,13,14), two studies evaluated different outcomes (bond strength and apical leakage) (15,16) and one study considered the evaluation in artificial teeth (17). Therefore, 10 articles were included in the review (Fig. 1). ...
Article
Full-text available
Background: The filling of the root canal system (RCS) is an important step in endodontic treatment and aims to obtain a three-dimensional sealing of the root canal spaces to prevent bacterial contamination. For this, the selection of an appropriate sealer must be performed synchronously with the choice of the root canal filling technique. This study aims, through an integrative review, to evaluate the quality of root canal filling by comparing thermoplastic and single-cone (SC) techniques. Material and methods: The Medline/PubMed, Scopus, Web of Science and Virtual Health Library (VHL) databases were used to find articles published until November 2021. The eligibility criteria comprised articles that evaluating the quality of root canal filling comparing thermoplastic techniques with the SC technique using tricalcium silicate-based sealer. Studies that evaluated primary teeth, endodontic retreatment or perforations, different outcomes, and studies that considered artificial teeth or different sealer and material for obturation of different techniques were excluded. For articles that were not available for access, an additional contact with authors were considered. A total of 1699 articles were found. After duplicate removal, the title and abstract of 828 articles were screened. Sixteen articles were considered for full-text analysis, but only ten articles met the eligibility criteria. Data extracted from the studies were discussed and tabulated to allow the comparison of desired factors. Results: Concerning the formation of gaps/voids, the thermoplastic techniques showed better results than the SC technique in 3 articles. On the other hand, 2 articles reported no statistical difference between the tested techniques. In addition, about the penetration of tricalcium silicate-based sealer in the dentinal tubules, of the 5 articles selected, in 4 there was no significant difference between the tested techniques and only one study showed better penetration of the sealer when using thermoplastic techniques. Conclusions: The thermoplastic technique was better in most selected studies regarding gaps and voids, but regarding the penetration of the sealer into the tubules, both techniques were effective. Key words:Root canal filling, thermoplastic techniques, tricalcium silicate.
Article
Full-text available
Anterior teeth restoration represents a challenge for dentists, who often rely on the dental technician’s wax-up. The proposed Stratified Stamp Technique (SST) allows for clinically reproducing the wax-up in a quick and easy way. A patient with fractures and discoloration on the upper central incisors was treated with resin-based composite direct restorations. Using SST, a 1 mm thick thermoformed polyethylene-terephthalate-glycol (PETG) template, based on the technician’s wax-up, was produced. Enamel Selective Area Reduction (SAR) was performed to guarantee adequate space for the restorations, and the fracture margins were rounded and finished. Traditional layering procedures according to the five color dimensions of teeth were performed, except for the final labial layer, which was realized with warm composite loaded inside the template and polymerized through it, in order to ensure accurate tooth morphology reproduction. SST offers a reliable method for transferring technician’s wax-up morphology to direct composite restorations in anterior teeth. Compared with other methods, SST allows for better isolation with a rubber dam and permits traditional layering with multiple composite shades, thus leading to satisfactory esthetic outcomes.
Article
Full-text available
Objective: The main objective of endodontic treatment is to remove microorganisms from the root canal space and prevents reinfection. Deep penetration of the dentinal tubule is advantageous because it increases the contact area between the root canal filling material and dentin, thereby increasing the sealing quality of the entire root canal system. Bioceramic sealers are biocompatible, nontoxic, non-shrinking, hydrophilic, and stable, do not expand during setting, and can form hydroxyapatite, which then forms chemical bonds with dentin to compare the abilities of three types of bioceramic-based sealers to penetrate the dentinal tubules.Methods: Obturation used three types of bioceramic sealers. Group 1 (calcium phosphate silicate), Group 2 (a mixture of tricalcium silicate and resin), and Group 3 (pure tricalcium silicate) were observed using a scanning electron microscope and measurement of the penetration distance with ImageJ.Results: The bioceramic sealers had statistically significant differences in penetration distance into dentinal tubules (p’s<0.001). The mean penetration value of Group 1 (calcium phosphate silicate) was 115.99 μm, Group 2 (a mixture of tricalcium silicate and resin) was 209.28 μm, and Group 3 (pure tricalcium silicate) was 84.07 μm.Conclusion: Although all three bioceramic sealers penetrated the dentinal tubules, they exhibited differences in their penetration capabilities. Group 2 had the deepest penetration, likely due to the resin content.
Article
Full-text available
Epoxy resin-based sealers are currently widely used, and several studies have considered AH Plus to be the gold-standard sealer. However, it still has limitations, including possible mutagenicity, cytotoxicity, inflammatory response, and hydrophobicity. Drawing upon the advantages of mineral trioxide aggregate, calcium silicate-based sealers were introduced with high levels of biocompatibility and hydrophilicity. Because of the hydrophilic environment in root canals, water resorption and solubility of root canal sealers are important factors contributing to their stability. Sealers displaying lower microleakage and stronger push-out bond strength are also needed to endure the dynamic tooth environment. Although the physical properties of calcium silicate-based sealers meet International Organization for Standardization recommendations, and they have consistently reported to be biocompatible, they have not overcome conventional resin-based sealers in actual practice. Therefore, further studies aiming to improve the physical properties of calcium silicate-based sealers are needed.
Article
Full-text available
Endodontic sealers for non-surgical root canal treatment (NSRCT) span many compositions and attributes. This comprehensive review discusses current types of endodontic sealers by their setting reaction type, composition, and properties: zinc oxide-eugenol, salicylate, fatty acid, glass ionomer, silicone, epoxy resin, tricalcium silicate, and methacrylate resin sealers. Setting time, solubility, sealing ability, antimicrobial, biocompatibility, and cytotoxicity are all aspects key to the performance of endodontic sealers. Because sealing ability is so important to successful outcomes, the relative degree of microleakage among all the relevant sealers was calculated by way of a meta-analysis of relevant literature. Compared to AH Plus, tricalcium silicate sealers show the lowest relative microleakage among the sealers assessed, followed by silicone sealers and other non-AH Plus epoxy resin sealers. Tricalcium silicate sealers also exhibit the most favorable antimicrobial effect and excellent biocompatibility. Future sealers developed should ideally combine a hermetic seal with therapeutic effects.
Article
Full-text available
(1) Aim: To perform a systematic review of the literature on the biocompatibility of root canal sealers that encompasses the various types of sealers that are commercially available as well as both in vitro and in vivo evidence. (2) Methods: This systematic review has been registered in PROSPERO (ID 140445) and was carried out according to PRISMA guidelines using the following databases: PubMed, Cochrane Library, ClinicalTrials.gov, Science Direct, and Web of Science Core Collection. Studies published between 2000 and 11 June 2019 that evaluated cytotoxicity (cell viability/proliferation) and biocompatibility (tissue response) of root canal sealers were included. (3) Results: From a total of 1249 studies, 73 in vitro and 21 in vivo studies were included. In general, studies suggest that root canal sealers elicit mild to severe toxic effects and that several factors may influence biocompatibility, e.g., material setting condition and time, material concentration, and type of exposure. Bioactive endodontic sealers seem to exhibit a lower toxic potential in vitro. (4) Conclusions: The available evidence shows that root canal sealers exhibit variable toxic potential at the cellular and tissue level. However, the methodological heterogeneity among studies included in this systematic review and the somewhat conflicting results do not allow a conclusion on which type of sealer presents higher biocompatibility. Further research is crucial to achieve a better understanding of the biological effects of root canal sealers.
Article
The ultimate objective of endodontic technique is the elimination of the root system as a source of infection and inflammation to the apical periodontium after irreversible pulp pathosis. The most desirable way to render root canals innocuous is to clean and shape them, to eliminate bacteria and tissue debris from within them, and then to obliterate them by means of a dense three-dimensional root canal filling. Accessory canals are present in practically all teeth. Many accessory canals are very small and calcify spontaneously during chronic pulp irritation, and others contain too little tissue to be clinically significant. Often, however, accessory canals are of considerable size, and, where the tissue within them becomes necrotic or infected, they may contribute to lateral root abscesses unless sealed off from the periodontal ligament. Root canal filling procedures should be directed toward the filling of significant lateral canals as well as the filling of main root canals (Fig. 8). Many techniques have been used to obturate root canals successfully. Most of these techniques employ either silver cones or gutta percha in some form. When used well, all of these techniques are valuable; when abused, no technique can succeed. The difficulty of adapting a silver cone to a less than geometrical round foramen sets certain potential limitations upon the use of silver cones in all cases. Likewise, small dimensional changes inherent in the use of gutta percha and a solvent, as well as certain problems of apical adaptation of the gutta percha when no solvent is used, encourages the evolvement of a technique by means of which gutta percha is rendered plastic without the use of solvents. Vertical condensation of warm gutta percha produces consistently dense, dimensionally stable, three-dimensional root canal fillings. Lateral canals are filled with extraordinary frequency, often with gutta percha, sometimes with cement. The final test of a root canal filling is its capacity to seal off the root canal system from the periapical tissues. The tissue compatibility of almost all commonly used root canal filling materials is very high, and for decades bone has been demonstrated to be laid down in close proximity to all of them. Overfilling, while not necessarily beneficial, will not prejudice the outcome of a case or prevent healing. Overfilling must be distinguished from overextension of underfilled cases.
Article
This study compared the depth and percentage of dentinal tubule penetration for single‐cone (SC) and warm vertical (WV) obturation techniques with two different bioceramic sealers (BC Sealer [BCS], BC Sealer HiFlow [BCSHF]) and an epoxy resin‐based sealer (2Seal easymiX). Fifty canals were filled with BCS, BCSHF or resin‐based sealer (RBS). Teeth in BCS and BCSHF groups were filled with SC or WV techniques, and teeth in the control group (RBS) filled with WV technique only. The roots were sectioned at 3 mm and 6 mm levels from the apex and evaluated with a confocal laser microscope. There was significantly greater depth and percentage of sealer penetration at the 6 mm section compared to 3 mm (P < 0.05). No statistically significant difference was found in sealer type or obturation technique at the examined levels (P > 0.05). In conclusion, dentinal tubule penetration was similar comparing BC Sealer, BC Sealer HiFlow and RBS using SC and WV techniques.
Article
Objective Warm vertical compaction of gutta-percha is a technique that is used by most specialists for root canal obturation. The sealers currently available exhibit irriversible chemical changes when heated. New biologically active sealers that do not sustain irreversible changes when heated are an attractive alternative to be used with warm vertical compaction obturation technique. The aim of this study was to measure the heat generated by warm vertical compactors inside the root canal, characterize a newly developed root canal sealer at different temperatures and verify its suitability at the actual temperature window used clinically. Methods The typical temperatures generated by two heat carriers in a root canal were assessed by thermocouples. Two premixed root canal sealers TotalFill BC and HiFlow BC (FKG, Switzerland) were allowed to set and they were characterized by scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS) and X-ray diffraction analysis (XRD) immediately after setting and by XRD after 28 days in physiological solution. The ion leaching in solution was assessed by inductively coupled plasma (ICP). The organic component was extracted in acetone and assessed by Fourier transform infrared spectroscopy (FT-IR) for both the unset sealer and sealer subjected to different temperatures. The heat profiles of both sealers were investigated by FT-IR and thermographic analysis. Results None of the devices tested achieved the temperatures set on the dial. The highest temperatures were coronal followed by apical for both devices. The sealers were identical except for the vehicle. The inorganic components included tricalcium silicate, dicalcium silicate and zirconium oxide. No calcium hydroxide was produced by any of the sealers after immersion in physiological solution but calcium was released in solution. The chemistry of both sealers was modified when heated but both recovered when cooled. Significance The heat carriers were unreliable and the heat generated inside the canal was not the same as the temperature set on the dial. Since both sealers had identical chemistry save for minimal modifications to the organic component and were both resistant to heat, TotalFill BC sealer is recommended for use with warm vertical compaction technique as it is cheaper and as effective as the HiFlow.
Article
Objective Removal of obturating materials from the root canal during retreatment is usually accomplished by mechanical means and organic solvents to dissolve the gutta-percha. This strategy is ineffective on sealers. The aim of this research was to assess the efficacy of mechanical instrumentation aided by targeted chemical means for removal of hydraulic sealers. Methods A preliminary study assessed the effect of 17% EDTA and 10/20% formic acid applied for 5 or 10 minutes on dentine and for 5 minutes on Totalfill BC sealer (FKG). Microhardness and structural integrity by scanning electron microscopy and energy dispersive spectroscopy were investigated. The optimal solutions were used as adjuncts to mechanical instrumentation to remove obturations made with single cone using a standard gutta-percha and bioceramic coated gutta-percha and Totalfill BC sealer. The removal of obturation material from the root canal system of obturated teeth was evaluated using microcomputed tomography. The canal patency and reestablishment of working length were also checked. Results The preliminary study showed that 17% EDTA and 10% formic acid applied for 5 minutes did not damage the dentine but effected the structural integrity of the sealer. 10% formic acid used in conjunction with mechanical instrumentation was the most efficient method to remove the obturation material from the root canal, achieving over 95% removal for both gutta-percha and the bioceramic coated version and also achieve patency and reestablishment of working length. Conclusions The use of a targeted irrigation protocol with a chemical adjunct to the mechanical instrumentation is the best way to retreat teeth obturated with hydraulic calcium silicate sealer and gutta-percha
Article
Aim: To investigate the chemical changes affecting different types of gutta-percha and endodontic sealers during heating, and correlate changes with the heating capacity of different heat carriers. Methodology: The heating capacity of three endodontic heat carriers were evaluated using thermocouples to produce heat profiles. The devices were activated at different temperature set-ups, in continuous or cut-out modes. Chemical changes of six brands of gutta-percha and four types of sealers were assessed in real-time during heating using micro-Raman spectroscopy equipped with a heating stage. Raman spectra of each tested material were averaged and compared at different temperature levels. The sealers were further assessed by Fourier transform infrared (FTIR) spectroscopy. Results: None of the tested heat carriers achieved the temperature levels that were set by the devices and recommended by the manufacturer. The use of continuous heating mode resulted in higher rises in temperature than the 4s cut-out mode that reached 110 °C. The various brands of gutta-percha exhibited different chemical changes in response to heat. Some changes even occurred below temperature levels generated by the heating devices. All sealers revealed changes in their chemical composition upon heating. Changes in epoxy resin- and zinc oxide eugenol-based sealers were detectable at 100 °C, with structural alterations beyond that temperature and irreversible changes after cooling. Water loss was irreversible in BioRoot, but its chemical structure was stable as well as for the TotalFill. Conclusions: The heating capacity of endodontic heat carriers needs to be standardized, so that the temperatures delivered by the tips is the same as that set on the dial. Practitioners should be aware of the actual temperatures generated by these devices, and the suitability of sealers to be used at the temperature levels achieved.
Article
The present micro‐computed tomography (micro‐CT) study compared the presence of voids in the band‐shaped isthmuses obturated by warm vertical compaction (WVC) and single‐cone (SC) techniques. Twenty mesial roots from mandibular first molar teeth showing a band‐shaped isthmus were selected and assigned into two groups based on their preoperative anatomical dimensions (n = 10), according to the filling technique: WVC or SC. Post‐filling micro‐CT scanning was performed. The percentage volume of root canal filling materials and voids were calculated and data were analyzed using the Mann–Whitney U test with a significance level of 5 and 95% confidence interval. Mean percentage volumes of filling materials and voids were 86.88 ± 8.53 and 13.11 ± 8.53 for the WVC group, 84.39 ± 8.30 and 15.60 ± 8.30 for the SC group, respectively, with no significant difference between them (p > .05). Neither WVC nor SC produced void‐free root canal fillings in the band‐shaped isthmuses and both techniques resulted in a similar quality of root canal filling. Quality of root canal filling is similar between warm vertical compaction and single‐cone obturation, yet not technique produced void free fillings within.