Upload
others
View
1
Download
0
Embed Size (px)
Citation preview
COMPARISON OF THE AREA OF
RESINBASED SEALER AND VOIDS IN ROOTS OBTURATED
WITH RESILON AND GUTTAPERCHA
Abstract
The aim of this study was to compare the crosssectional area of sealer+void of a new
resinbased sealer (Epiphany) surrounding root fillings completed with a polymerbased
obturation material (Resilon) and laterallycompacted guttapercha, following root canal
preparation with System GT instruments rotary instruments. Twentyfour extracted human
mandibular premolars were selected and the canals were prepared to a final size of 40
(0.06 taper). The teeth were randomly assigned into two groups (n=12/group) for the
filling procedures: Group 1: Resilon cones, and Group 2: Guttapercha. In both groups
Epiphany was used as a sealer. Horizontal sections were obtained every 1mm up to 5mm
from the apical foramen. Sections were digitally photographed under a stereomicroscope
and the images were transferred to an IBMcompatible PC for image analysis. The cross
sectional area of the root canal and the area occupied by the sealer and voids were
calculated for each section, and compared statistically. No differences were found between
the sealer+void area of Resilon or guttapercha groups at any level of sectioning (Friedman
test, P>0.05). Comparisons within each obturation group showed that there was no
significant difference between any level of sectioning with regard to the ratio of
sealer+void area to that of the root canal (MannWhitney U test, P>0.05). Within the
experimental conditions of the present study, both obturating techniques using the new
resinbased Epiphany sealer exhibited similar amounts of sealer+void area, regardless of
the apical level of sectioning compared.
2
INTRODUCTION
Complete obturation of the root canal with an inert filling material and creation of a
fluidtight seal are among the major goals of successful endodontic treatment (1).
Numerous obturation techniques and filling materials have been used to obtain this
objective, while guttapercha continues to be the material of choice owing to its unique
chemical and physical properties (2). Recently, Resilon Research LLC (Madison, CT,
USA) introduced Resilon obturating points and resin sealer. This product is used in
combination with a selfetching primer to create a solid monoblock (3). Resilon is a
thermoplastic synthetic resin material that is based on polymers of polyester and contains a
bifunctional methacrylate resin, bioactive glass and radiopaque fillers (4). The sealer,
Epiphany Root Canal Sealant (Pentron Clinical Technologies, Wallingford, CT, USA) is a
dual curable resin sealer, containing bisphenolA diglycidyl dimethacrylate (BisGMA),
ethoxylated BisGMA, urethane dimethacrylate (UDMA), hydrophilic difunctional
methacrylates, silanetreated barium borosilicate glasses, barium sulfate, silica, calcium
hydroxide, bismuth oxychloride with amines, peroxide, photo initiator, stabilizers and
pigment. The primer is an aqueous solution of an acidic monomer. The system also
includes pellets that can be used for backfilling in thermoplasticized techniques (3).
Previous studies have evaluated various aspects of this new obturation system including
microbial leakage, bond strength, sealing ability and fracture resistance (47).
Although the Epiphany sealer has been primarily developed to be used in
combination with a polymerbased obturator, the use of Epiphany sealer in conjunction
3
with guttapercha cones could offer a potential advantage, as guttapercha does not adhere
to the dentinal walls (8), and thus, needs to be used with a material that adequately seals
the canal. The Epiphany sealer is capable of bonding to root canal dentin (9), and a tight
bond between the resinbased sealer and dentin could help minimize subsequent leakage
that may occur between the sealer and dentin. A recent fluidfiltration study has shown that
the combination of guttapercha core and Epiphany sealer had significantly higher sealing
ability than that of the Resilon core and Epiphany (6). Also, the combined use of gutta
percha and Epiphany has shown significantly greater bond strength than Resilon and
Epiphany (10).
Today, most root canal filling methods utilize different formulations of gutta
percha, cemented into the root canal with a sealer (1114). Endodontic sealers are capable
of filling imperfections, patent accessory canals and multiple foramina; and increasing the
adaptation of guttapercha (15). On the other hand, root canal sealers are not dimensionally
stable, and may dissolve partially over time due to their low resistance to leakage (1618).
Thus, in order to achieve optimal results, the amount of sealer should be minimized, while
increasing the mass of the core filling material (1823). In light of these observations, the
purpose of this study was to investigate and compare the crosssectional area of
sealer+voids in the apical region of root canal fillings completed with laterallycompacted
Resilon and guttapercha cones with the new resinbased Epiphany sealer.
MATERIALS AND METHODS
4
Specimen Preparation
Freshlyextracted, periodontally involved singlerooted mandibular human
premolars were placed in 0.9 % wt/vol NaCl solution and stored at 40C until actual
experiments (a maximum of 1 month). The teeth were transferred to room temperature 24
hours before experimental procedures. Following removal of debris and tissue remnants
from the root surfaces, crowns were removed at cementoenamel junction using a low
speed diamond saw (Isomet 4000, Buehler, Lake Bluff, IL, USA) under coolant water.
Inclusion criteria stipulated that the roots were macroscopically similar in size and that the
root canals were straight and single, as verified radiographically. 24 roots were selected
accordingly and were, then, reduced to a standardized size of 18 mm from the coronal
aspect. Patency of the apical foramen was determined with a size 10 Kfile (Dentsply
Maillefer, Ballaigues, Switzerland). The working length was established 1mm short of the
apical foramen. The canal orifices were coated with sticky wax resin to prevent the
outflow of the irrigating solution through the apical foramen. The middle and coronal
thirds of roots were prepared using ISO size 50, 70, 90 and 110 Gates Glidden drills
(Produits Dentaires S.A., Vevey, Switzerland). Roots were further instrumented with the
System GT NiTi rotary files (Dentsply Maillefer, Ballaigues, Switzerland) in a crown
down manner. All canals were enlarged to size 40, (0.06 taper) at the established working
length. Each instrument was used to enlarge five root canals. Between each instrument
size, the canals were irrigated with 5 mL 2.5% NaOCl using a 27gauge needle. Because
closure of canal orifices with wax could result in pooling of the irrigant that could affect
5
the time that the irrigant was in contact with the walls, irrigation procedures were
performed with the roots held upsidedown (24). Following preparation, the root canals
received a final irrigation of 5 mL 17% EDTA (Pulpdent, Watertown, MA, USA) and 5
mL 2.5% NaOCl, after which the canals were flushed with distilled water (10 ml) in order
to avoid the prolonged effect of EDTA and NaOCl. The roots were dried with paper points
and, thereafter, randomly assigned into two obturation groups (n=12/each):
Group 1: After instrumentation, a size 40, 0.06 taper Resilon cone (Pentron) was inserted
to the working length and a tight fit was assured by obtaining a small degree of resistance
or “tugback” on removal. A selfetching primer (Epiphany Primer, Pentron) was placed
into the canal with a syringe. The Epiphany primer was allowed to remain for 30s and the
excess was removed with a paper point. For the purpose of standardization, 0.05 mL of
freshly mixed Epiphany sealer (Pentron) was injected into the canal orifice with a 0.5 mL
insulin syringe. Then, a master Resilon cone (size 40, 0.06 taper) was gently seated into the
canal and condensed with a #25 finger spreader (Dentsply Maillefer, Ballaigues,
Switzerland). Fine accessory Resilon cones (Pentron) were inserted until they could not be
introduced more than 3 mm into the root canal. In each root canal, approximately four
accessory cones were inserted and the quality of the root canal fillings were confirmed
with periapical radiographs. Excess cones were removed using a warm excavator and final
vertical compaction was completed with a size 11 plugger to a depth of approximately 1
mm.
6
Group 2: The Epiphany primer and sealer were applied into the root canals as with
group 1. Thereafter, a size 40, 0.06 taper guttapercha master point (Dentsply Maillefer)
was seated into the root canal with tugback. Then, lateral compaction was performed as
with group 1 using accessory guttapercha cones. Removal of the excess guttapercha
cones and final vertical compaction was accomplished in the same manner.
As per the manufacturer’s instructions, all roots were lightcured for 40s from the
coronal aspect. The coronal access of all specimens was restored using a hybrid resin
composite material (Spectrum TPH, Dentsply), bonded with a totaletch singlebottle
adhesive system (Prime & Bond NT, Dentsply). To avoid discrepancies owing to operator
variations, all clinical procedures were performed by the same operator.
Sectioning and image analysis
The specimens were stored separately for two weeks at 37 °C and 100% humidity
to allow the sealer to set completely. Filled roots were, then, embedded in epoxy resin
(Araldite M, Agar Scientific Limited, Essex, UK). For each specimen, horizontal sections
were obtained every 1 mm up to 5 mm from the apical foramen, using a diamond saw
(Isomet 4000) at the lowest speed setting (200 rpm). During sectioning procedures, the
specimens were subjected to continuous water cooling to prevent frictional heat, and thus,
smearing of Resilon or guttapercha that could tend to hide areas of sealer. Thereafter,
digital photographs of the coronal surface of sections were obtained at 40x magnification
under a stereomicroscope (Microflex, Nikon, Tokyo, Japan) and transferred to an IBM
compatible PC as uncompressed TIFF files. AutoCAD 2000 software (Autodesk Inc., San
7
Rafael, CA, USA) was used to calculate the crosssectional area of the root canal and the
area filled by the sealer (and voids, if present) (Figure 1).
For each specimen, the ratio of sealer+voids to root canal area was calculated by
dividing sealer+void area by the root canal area. SPSS statistical software (Ver. 11.5, SPSS
Inc., Chicago, Ill, USA) was utilized for statistical analysis of the data. For each section (1
5mm), statistical comparisons between the Resilon and guttapercha groups were made
using MannWhitney U test with Bonferroni correction (P=0.05). Differences within each
obturation group for each level of sectioning were analyzed statistically with Friedman test
(P=0.05).
RESULTS
For every level of sectioning (15 mm), the ratio of the crosssectional area of
sealer+voids to that of the root canal is presented in Table 1 as means and standard
deviations. When group 1 (Resilon + Epiphany) and group 2 (Guttapercha + Epiphany)
were compared statistically, there were no significant differences at any of the levels tested
(Figure 2, p=0.755).
Comparisons within each obturation group showed that there was no significant
difference between any level of sectioning with regard to the ratio of sealer area to that of
the root canal (p=0,232 for Resilon+Epiphany, and p=0,194 for guttapercha+Epiphany
groups, respectively).
8
DISCUSSION
The quality of the root canal filling in the apical third is important (25), and
assuming that minimal sealer thickness and fewer voids are good measures of longterm
sealing ability (23), this study was designed to quantify and compare the presence of
sealer+voids within the 15 mm apical level using Resilon and guttapercha cones with the
new resinbased Epiphany sealer. Although not generally recommended, some researchers
have preferred not to use a sealer to prevent methodological problems such as
standardizing the volume of sealer (21, 25, 26). Indeed, despite a standardized amount of
sealer being used in the present study, it may be difficult to standardize the amount of
sealer reaching the apical region (21). On the other hand, including a sealer may facilitate
guttapercha movement (21), and more notably, simulate the clinical condition (27).
Previous studies comparing the sealing ability of Epiphany + guttapercha and
Epiphany + Resilon combinations have reported conflicting results. Utilising a bacterial
leakage test with Streptococcus mutans and Enterococcus faecalis, Shipper et al. (4) have
reported significantly higher leakage with the Epiphany + guttapercha combination,
compared to that of the Epiphany + Resilon system. The superior sealing capability of the
latter root filling system was attributed to the “monoblock” which is created by adhering
of the Epiphany sealer to both the Resilon filling and to the dentin walls (4). Contrary,
using a highlysensitive computerized fluid filtration meter, Onay et al. (6) reported that
the combination of guttapercha core and Epiphany sealer had significantly higher sealing
9
ability than that of the Resilon core and Epiphany. Citing their previous work in which
both filling combinations were compared in terms of pushout bond strength test (10), the
authors inversely correlated the higher bond strength of the Epiphany sealer and gutta
percha combination with the lower apical leakage obtained in their computerised fluid
filtration study. It was also explained that guttapercha is more compactable than Resilon,
and thus, it may partially compensate for interfacial stresses generated by lateral
compaction. In agreement with the findings of Onay et al. (6), a transmission electron
microscopy study (28) has shown the presence of silver deposits along the sealerhybrid
layer interface in the Epiphany + Resilon system, concluding that the quality of apical seal
achieved with the latter system was not superior to AH Plus + guttapercha combination.
A recent study by Epley et al. (29) evaluated the presence of voids when the
Epiphany system was used for obturating the root canal system. In that study, the
specimens were instrumented with hand and rotary files, and sectioned at 1, 3, and 5 mm
from the apex. The authors showed that lateral condensation with guttapercha and Roth
sealer (Roth International LTD., Chicago, IL) had significantly more voids at the 3mm
level, compared to both vertically or laterally compacted Epiphany and Resilon
combinations, and continuous wave guttapercha with Roth sealer. In contrast to the
findings of Epley et al. (29), there was no significant between the test groups of the present
study, including those obtained at the 3mm level of sectioning. This difference may be due
to the type and size of the specimens, the type and taper of instruments, and the use of
different sealers. In the study of Epley et al. (29), palatal and distal roots of extracted first
10
molars were used and enlarged with hand file #20, ProTaper rotary files (sizes S1, S2, F1,
Dentsply, Tulsa, OK) and size 40, 0.04 taper ProFile instruments (Dentsply). In addition,
finemedium guttapercha master points (Dentsply Maillefer) that had been trimmed to a
size 40 (taper unknown) were used with the Roth sealer. In the present study, the selected
mandibular premolar roots were very similar in buccolingual and mesiodistal
dimensions, and were adjusted to a standardized length of 18 mm. Moreover, all roots
were flared using the same sequence of Gates Glidden drills, instrumented with the same
NiTi rotary files (System GT) and, obturated with cones conforming to the size (40) and
taper (0.06) of the final rotary files used. Despite all attempts to provide standardization,
the high standard deviations obtained in the present study highlight the problem of using
natural teeth instead of resin blocks with simulated root canals (30), and cannot be
compared with those of Epley et al. (29) since the authors did not report the standard
deviations. Nevertheless, it is noteworthy to mention herein that despite all these
differences, both studies report no significant differences between the test groups at levels
other than 3mm. It would, thus, seem reasonable to speculate that the use of master gutta
percha cones with the same taper of the prepared root canal is an optimalbut not
mandatoryprocedure to achieve minimal sealer area and voids with the Epiphany sealer at
the apical region.
Within the experimental conditions of the present study, both obturation methods
using the Epiphany sealer displayed similar amounts of the sealer+void component,
regardless of the levels of sectioning investigated. Because coronal microleakage has also
11
been cited as a significant cause of posttreatment endodontic failure, further studies
should be conducted to assess the adaptation of the tested obturation methods in the
coronal third.
12
REFERENCES
1. Nguyen NT. Obturation of the root canal system. In: Cohen S, Burns RC, ed. Pathways
of the pulp, 3rd edn;1984; pp:20599. St Louis: CV Mosby Co.
2. Levitan ME, Himel VT, Luckey JB. The effect of insertion rates on fill length and
adaptation of a Thermoplasticized guttapercha technique. J Endod 2003;29:5058.
3. Teixeira FB, Teixeira EC, Thompson J, Leinfelder KF, Trope M. Dentinal bonding
reaches the root canal system. J Esthet Restor Dent. 2004;16(6):34854.
4. Shipper G, Ørstavik D, Teixeira FB, Trope M An evaluation of microbial leakage in
roots filled with a thermoplastic synthetic polymerbased root canal filling material
(Resilon). J Endod 2004;30:342–7.
5. Hiraishi N, Papacchini F, Loushine RJ, Weller RN, Ferrari M, Pashley DH, Tay FR.
Shear bond strength of Resilon to a methacrylatebased root canal sealer. Int Endod J
2005; 38:75363.
6. Onay EO, Ungor M, Orucoglu H. An in vitro evaluation of the apical sealing ability of a
new resinbased root canal obturation system. J Endod 2006;32:9768.
7. Sagsen B, Er O, Kahraman Y, Akdogan G. Resistance to fracture of roots filled with
three different techniques. Int Endod J 2007;40:31–5.
8. Stratton RK, Apicella MJ, Mines P. A fluid filtration comparison of guttapercha versus
Resilon, a new soft resin endodontic obturation system. J Endod 2006;32:6425.
9. Nakabayashi N, Watanabe A, Gendusa NJ. Dentin adhesion of ‘modified’ 4
META/MMATBB resin: function of HEMA. Dent Mater 1992;8:259–64.
13
10. Ungor M, Onay EO, Orucoglu H. Pushout bond strengths: the EpiphanyResilon
endodontic obturation system compared with different pairings of Epiphany, Resilon, AH
Plus and guttapercha. Int Endod J 2006;39:6437.
11. Dummer PM. omparison of undergraduate endodontic teaching programmes in the
United Kingdom and in some dental schools in Europe and the United States. Int Endod J
1991;24:16977.
12. Leung SF, Gulabivala K. An invitro evaluation of the influence of canal curvature on
the sealing ability of Thermafil. Int Endod J 1994;27:1906.
13. Peak JD, Hayes SJ, Bryant ST, Dummer PM. The outcome of root canal treatment. A
retrospective study within the armed forces (Royal Air Force). Br Dent J 2001;190:140–4.
14. Schäfer E, Olthoff G. Effect of three different sealers on the sealing ability of both
thermafil obturators and cold laterally compacted guttapercha. J Endod 2002;28:63842.
15. Wu MK, Van B, Wesselink PR. Diminished leakage along root canals filled with gutta
percha without sealer over time: a laboratory study. Int Endod J 2000;33:1215.
16. Kontakiotis EG, Wu MK, Wesselink PR. Effect of sealer thickness on longterm
sealing ability: a 2year followup study. Int Endod J 1997;30:30712.
17. Peters DD. Twoyear in vitro solubility evaluation of four Guttapercha sealer
obturation techniques. J Endod 1986;12:13945.
14
18. Georgopoulou MK, Wu MK, Nikolaou A, Wesselink PR. Effect of thickness on the
sealing ability of some root canal sealers. Oral Surg Oral Med Oral Pathol Oral Radiol
Endod 1995;80:33844.
19. Schilder H (1967) Filling of root canals in three dimensions. Dent Clin North Am.
1967;11:72344.
20. Gencoglu N, Garip Y, Bas M, Samani S. Comparison of different guttapercha root
filling techniques: Thermafil, Quickfill, System B and lateral condensation. Oral Surg Oral
Med Oral Pathol Oral Radiol Endod 2002;93:3336.
21. Wu MK, van der Sluis LWM, Wesselink PR. A preliminary study of the percentage of
guttaperchafilled area in the apical canal filled with vertically compacted warm gutta
percha. Int Endod J 2002;35:52735.
22. Wu MK, De Groot SD, van der Sluis LWM, Wesselink PR. The effect of using an
inverted master cone in a lateral compaction technique on the density of the guttapercha
fill Oral Surg Oral Med Oral Pathol Oral Radiol Endod 2003;96:34550.
23. Weis MV, Parashos P, Messer HH. Effect of obturation technique on sealer cement
thickness and dentinal tubule penetration. Int Endod J 2004;37:65363.
24. Altundasar E, Ozcelik B, Cehreli ZC, Matsumoto K. Ultramorphological and
histochemical changes after ER,CR:YSGG laser irradiation and two different irrigation
regimes. J Endod 2006;32:4658.
15
25. DeDeus G, GurgelFilho ED, Malaghaes KM, CoutinhoFilho T. A laboratory analysis
of guttaperchafilled area obtained using Thermafil, System B and lateral condensation.
Int Endod J 2006;39:37883.
26. Smith RS, Weller NR, Loushine RJ, Kimbrough WF. Effect of varying the depth of
heat application on the adaptability of guttapercha during warm vertical compaction.
J Endod 2000;26:66872.
27. Gulsahi K, Cehreli ZC, Kuraner T, Dagli FT. Sealer area associated with cold lateral
condensation of guttapercha and warm coated carrier filling systems in canals prepared
with various rotary NiTi systems. Int Endod J 2007;40:27581.
28. Tay FR, Loushine RJ, Weller RN, et al. Ultrastructural evaluation of the apical seal in
roots filled with a polycaprolactonebased root canal filling material. J Endod 2005;31:
514 –9.
29. Epley SR, Fleishman J, Hartwell G, Cicalese C. Completeness of root canal
obturations: Epiphany techniques versus guttapercha techniques. J Endod 2006;32:5414.
30. Gordon MP, Love RM, Chandler NP. An evaluation of .06 tapered guttapercha cones
for filling of .06 taper prepared curved root canals. Int Endod J 2005;38:8796.
16
FIGURE LEGENDS
Figure 1. Representative 5mm sections of Resilon + Epiphany (A) and guttapercha +
Epiphany (B) groups, demonstrating guttapercha (G), Resilon (R), sealer (S), and void
(V).
Figure 2. The ratio of the crosssectional area of sealer + voids to the area of root canal at
15 mm, and corresponding representative sections for each obturation method tested.
Table 1. The ratio of the crosssectional area of sealer + voids to the area of root canal.
17
Table 1. The ratio of the crosssectional area of sealer+voids to the area of root canal.
Section(mm) n
Group 1 ( Resilon + Epiphany )
Mean SD
Group 2 ( Guttapercha + Epiphany )
Mean SD 1 12 0.121 0.182 0.111 0.178
2 12 0.058 0.068 0.123 0.200
3 12 0.042 0.084 0.082 0.118
4 12 0.052 0.071 0.061 0.095
5 12 0.073 0.076 0.014 0.028