sealing ability of a new polydimethylsiloxane-based root canal filling material
TRANSCRIPT
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Basic Research—Technology
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ealing Ability of a New Polydimethylsiloxane-based Rootanal Filling Material
hmet R. Özok, PhD, Lucas W. M. van der Sluis, PhD, Min-Kai Wu, PhD,nd Paul R. Wesselink, PhD
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bstracte tested the null hypothesis that there is no difference
n the sealing ability of GuttaFlow, RoekoSeal, andH26 in root canals. Sixty extracted mandibular pre-olars were filled with AH26 (lateral compaction),oekoSeal, or GuttaFlow (modified single-cone). Theealing ability of the root canal fillings was measuredeekly (4 weeks) by using a glucose penetration model.ruskal-Wallis test revealed significant differences inlucose penetration between the experimentalroups at weeks 1, 2, 3, and 4. Whereas GuttaFlowhowed the highest amount of leakage at all times,H26 showed the lowest. There was no significantifference between RoekoSeal-filled and AH26-filledoot canals throughout the experimental period.H26 showed better sealing ability in root canals
han GuttaFlow. (J Endod 2008;34:204 –207)
ey WordsH 26, GuttaFlow, leakage, polyvinlysiloxane, RoekoSeal,
oot canal filling material, sealing ability
From the Department of Cariology Endodontology Pedodon-ology, Academic Center for Dentistry Amsterdam (ACTA), Am-terdam, The Netherlands.
Address requests for reprints to Ahmet R. Özok, PhD,epartment of Cariology Endodontology Pedodontology, Ac-demic Center for Dentistry Amsterdam (ACTA), Louwesweg 1,066 EA Amsterdam, The Netherlands. E-mail address: [email protected]/$0 - see front matter
Copyright © 2008 by the American Association ofndodontists.oi:10.1016/j.joen.2007.11.005
04 Özok et al.
he major goal of a root canal filling is to prevent (re)infection of the root canal vialeakage of microorganisms and their by-products. The sealing ability of a root canal
illing material is, therefore, an important factor in achieving this goal. A new glucoseenetration method (1, 2) appears to be a useful tool to quantitatively, nondestructively,nd longitudinally measure the sealing ability of root canal filling materials.
The sealing ability of Roekoseal (Coltène/Whaledent, Langenau, Germany), a poly-imethylsiloxane-based root canal filling material, in combination with single-cone
echnique (3) or in combination with cold lateral compaction technique (4, 5), ap-ears favorable. RoekoSeal expands by 0.2% during the first 4 weeks and remains stable
hereafter (6). This feature might improve its sealing ability without forming excessiveorces within the root canal.
RoekoSeal is considerably less cytotoxic than epoxy resin– based root canal seal-rs, AH Plus (Dentsply/DeTrey, Konstanz, Germany) (7) and Top Seal (Dentsply/Derey) (8), and has little apoptotic effect on cells exposed to it (9).
A new polydimethylsiloxane-based root canal filling material, GuttaFlow (Coltène/haledent), has the same composition as RoekoSeal, except for the added gutta-percha�30 �m) and nanosilver particles. It has been introduced to the market as the firstonheated, flowable gutta-percha that, unlike heated gutta-percha, does not shrink.ccording to the manufacturer, GuttaFlow has excellent flow properties because itsiscosity diminishes under shear stress (thixotropicity).
GuttaFlow has similar cytotoxicity to Teflon controls at 24 hours after mixing (10),hich increases over time (72 hours); however, it remains significantly less than that ofH Plus.
We tested the null hypothesis that there is no difference in sealing ability betweenoot canals filled with GuttaFlow or RoekoSeal in combination with a modified single-one technique or with AH26 in combination with cold lateral compaction technique.
Material and MethodsSeventy recently extracted human mandibular premolars with single canal and
tored in 0.01% sodium azide (NaN3) were used. All the teeth had closed apices, noracks, and no signs of excessive aging. On buccolingual and mesiodistal radiographsf the teeth, which were taken to exclude the presence of a second canal, the canaliameters at the apical 4 mm were measured. The teeth were then distributed among thexperimental groups (groups 1–3) (n � 20) and the negative control group (n � 10),ccording to the average canal diameter. A Kruskal-Wallis test showed no statisticallyignificant difference between the groups regarding their average diameters (P �999).
reparation of the SpecimensThe teeth were embedded in self-polymerizing methyl methacrylate resin cylinders
Dentimex, Zeist, Netherlands), leaving the apical one third of the root uncovered, andere decoronated at 14 mm from the apex. The margins adjoining the root and resinere sealed with cyanoacrylate glue (Permacol, Ede, Netherlands). Except for thepical foramen and the coronal access, the whole specimen surface was covered with 2ayers of nail varnish. In the controls, the whole surface was covered.
The samples were kept at 37°C and 100% humidity at all times.
JOE — Volume 34, Number 2, February 2008
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Basic Research—Technology
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nstrumentation and Obturation of the Root CanalsA size 15 K-file was inserted in the root canal until it was just visible
t the apical foramen. The root canals were prepared 1 mm short of thisength by using GT-rotary instruments (Dentsply Maillefer, Ballaigues,witzerland) to a 0.06 taper master apical size of 30. After each instru-ent size, canals were rinsed with 2 mL 2% sodium hypochlorite
NaOCl). After completion of the preparations, the canals were alsoinsed with 2 mL 2% NaOCl, a size 15 K-file was inserted in the rootanal, and the remaining irrigant was ultrasonically activated (P5-Su-rasson; Satelec, Merignac, France) (1 minute). The canals were thenlushed with 0.5 mL 17% ethylenediaminetetraacetic acid solution1 minute). Subsequently, the canals were rinsed with 2 mL NaOCl,eionized water, and 80% ethanol, respectively, and dried with paperoints. The patency of the apical foramen was ascertained by insertinghe tip of a size 15 file through it.
roup 1AH26 (Lot 0411000575, 2009-10) was mixed according to the
anufacturer’s recommendations. A size 30 gutta-percha master cone
igure 1. Schematic drawing of the glucose penetration setup used to measurehe sealing ability of the root canal filling materials in the present study.
ABLE 1. Mean (standard deviation [SD]) and Median (range) of Glucose Pene
Group
1
AH26Mean (SD) 0.02 (0.06)Median (range) 0.0 (0–0.2)
RoekoSealMean (SD) 0.08 (0.2)Median (range) 0.0 (0–0.6)
GuttaFlowMean (SD) 0.3 (0.4)
Median (range) 0.0 (0–0.8) 0.2OE — Volume 34, Number 2, February 2008 S
Henry Schein, Gillingham, UK) was lightly coated with the AH26 pastend inserted into the canal to working length. With a spreader size B and–10 size 25 cones, the root canals were filled (cold lateral compac-
ion).
roup 2RoekoSeal (Lot 008, 2008-08) was mixed according to the man-
facturer’s recommendations and introduced into the root canals withentulo spirals rotating slowly to 1 mm short of the working length. A size0 gutta-percha master cone at working length and then two size 25utta-percha cones were inserted passively (modified single-cone).
roup 3GuttaFlow (Lot 106027, 2006-09) was mixed on a Silamat S5
Vivadent, Schaan, Liechtenstein) according to the manufacturer’s rec-mmendations. The canals were filled with GuttaFlow in the same man-er as described in group 2.
In a pilot study, root canals filled with gutta-percha cones withoutny sealer and any warm vertical forces were used as positive controls.hese samples exhibited substantial amount of leakage within the firsteek.
Root canals filled in the same manner as described in group 1 wereompletely sealed with nail varnish (including the apical foramen andhe coronal access) to serve as negative controls.
easurement of the Sealing AbilityWe used a modified glucose penetration setup (1, 2). Briefly, the
pecimen was connected to a 16-cm-long glass pipette (Pyrex, Acton,A) via a silicon-rubber tube and stainless steel wires (Fig. 1). The
ssembly was then placed in a sterile bottle with a screw cap. An openystem was created by drilling a uniform hole in the screw cap. Thepper chamber contained 14 cm of 1 mol/L glucose and 0.02% NaN3olution (approximately 4.5 mL), which created a hydrostatic pressuref 1.5 kPa (2). Lower chamber contained 2 mL 0.02% NaN3 solution.he whole setup was stored in a closed jar (100% humidity, 37°C)
hroughout the experiment. On days 7, 14, 21, and 28, a 100-�L aliquotrom the lower chamber was taken, and 100 �L sterile NaN3 solutionas added. The glucose concentration (g/L) in the aliquot was mea-
ured with a glucose assay kit (D-glucose-HK; Megazyme, Wicklow,reland) and a spectrophotometer (Spectramax plus; Molecular De-ices, Sunnyvale, CA) at 340 nm wavelength. In a pilot study, triplicateeasurements were reproducible (with differences at the third deci-al); therefore, here the measurements were taken only once.
The glucose assay has a lower detection limit of 0.04 g/L. Thealues below this were considered unreliable and recorded as 0 (noeakage). Similarly, once leakage exceeded 0.8 g/L, samples were noonger observed because the glucose concentration in the lower cham-er suggested substantial leakage had occurred.
n (g/L) along the Root Canal Filling
Week
2 3 4
(0.2) 0.2 (0.3) 0.2 (0.3)(0–0.8) 0.0 (0–0.8) 0.0 (0–0.8)
(0.3) 0.2 (0.3) 0.3 (0.3)(0–0.8) 0.0 (0–0.8) 0.0 (0–0.8)
(0.4) 0.5 (0.4) 0.5 (0.4)
tratio
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0.20.0
0.4
(0–0.8) 0.8 (0–0.8) 0.6 (0–0.8)ealing Ability of New Polydimethylsiloxane-based Root Canal Filling Material 205
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tatistical AnalysisData were analyzed on SPSS 12.0.1 software for Windows (SPSS
enelux, Gorinchem, Netherlands). A Kruskal-Wallis test assessed over-ll differences between the groups. Once overall differences were ob-erved, pair-wise comparisons were performed with a Mann-Whitney Uest. We considered values of P � .05 as significant.
ResultsThe results are summarized in Table 1. Fig. 2 shows the mean
lucose penetration in root-filled teeth.Negative control specimens showed no detectable glucose pene-
ration for 4 weeks.The differences between the groups at weeks 1, 2, 3, and 4 were
ignificant (P � .022, .034, .002, and .026, respectively).No significant difference in glucose penetration between root ca-
als filled with AH26 or RoekoSeal was found throughout the experi-
igure 2. Mean glucose penetration along the root canal filling per group over
igure 3. Percentage of specimens with detectable glucose penetration alon
ignificantly different (P � .05).06 Özok et al.
ental period. AH26 showed significantly less glucose penetration thanuttaFlow throughout the experiment (at weeks 1, 2, 3, and 4) (P �
010, .018, .004, and .008, respectively). At weeks 1, 2, and 4, there waso statistically significant difference between RoekoSeal-filled anduttaFlow-filled root canals. At the third week, RoekoSeal showedignificantly less glucose penetration than GuttaFlow (P � .004).uttaFlow showed the highest amount of glucose penetration at all timeoints.
The percentages of specimens with detectable glucose penetrationo the whole group are shown in Fig. 3. At weeks 1 and 2, no significantifference was observed in the percentage of root canal fillings withlucose penetration between the groups. At week 3, both AH26 andoekoSeal groups had significantly lower percentage of specimens withlucose penetration than GuttaFlow (P � .030). At week 4, only AH26howed significantly less percentage of specimens than GuttaFlow (P �030). Throughout the experiment, no significant difference between
oot canal filling. Bars with the same superscript letters are not statistically
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H26 and RoekoSeal groups in percentage of specimens with glucoseenetration was observed.
DiscussionWe should reject the null hypothesis because after 2 weeks AH26-
illed root canals showed significantly better sealing ability than rootanals filled with GuttaFlow.
In a fluid-filtration study (11), GuttaFlow with single-cone pro-ided inferior coronal seal than that of AH Plus. The authors recom-ended placement of accessory cones to reduce sealer thickness coro-
ally (11). In another fluid filtration study (12), GuttaFlow also showednferior sealing than AH Plus in combination with different obturationechniques. When a lentulo spiral and no gutta-percha cones were used,uttaFlow provided a similar seal to that of AH Plus. Because we used
entulo spiral to introduce GuttaFlow into the canals, the differenceetween the findings can be due to use of gutta-percha cones in thistudy. We speculate that the matrix of this thixotropic sealer might flownder the pressure applied by the inserted gutta-percha cones, leavingnly the gutta-percha particles between the cones and the dentin wall.nother possible explanation might be the higher sensitivity of the glu-ose penetration setup over the fluid filtration (2).
At week 4, a slight decrease in glucose penetration but no changen the percentage of leaking samples was seen in the AH26 anduttaFlow groups. The amount of gutta-percha in these groups mightxplain this. AH26 (lateral compaction) and GuttaFlow (gutta-perchaowder) groups contained more gutta-percha than RoekoSeal group.utta-percha might expand after prolonged storage in water (13).
ElAyouti et al (14) evaluated the presence and area of the voidsithin GuttaFlow fillings and between the sealer and the root canal wallt 5 apical-coronal levels. Although they observed that the mean area ofhe voids was the lowest in GuttaFlow group, the frequency of the voidsas significantly higher than the conventional cold lateral and warm
ertical compaction of gutta-percha in combination with AH Plus. This isomewhat in accord with our findings. The glucose leakage model usedn the present study is able to detect a true void (a through-and-throughoid that communicates with both ends of the filling), but a cul-de-sacype void (porosity) might remain undetected. In the study by ElAyoutit al, the significantly high frequency of the voids at all measurement
evels in the GuttaFlow group, although smaller in area, indicates anOE — Volume 34, Number 2, February 2008 S
ncreased possibility of communication between these voids and thepical and coronal ends of the root canal filling. They also observed thatn this group the voids were almost always within the sealer itself but nott the sealer-dentin interface. The porosity of the sealer might be a resultf using a lentulo spiral to place the highly viscous gutta-percha paste
nto the canal or simply because of the manufacturing process.In this in vitro study, AH26 showed the lowest amount of leakage
nd GuttaFlow the highest. There was no significant difference betweenhe sealing ability of AH26 and RoekoSeal at all times.
References1. Xu Q, Fan MW, Fan B, Cheung GS, Hu HL. A new quantitative method using glucose for
analysis of endodontic leakage. Oral Surg Oral Med Oral Pathol Oral Radiol Endod2005;99:107–11.
2. Shemesh H, Wu M-K, Wesselink PR. Leakage along apical root fillings with andwithout smear layer using two different leakage models: a two-month longitudinal exvivo study. Int Endod J 2006;39:968 –76.
3. Wu M-K, van der Sluis LWM, Wesselink PR. A 1-year follow-up study on leakage ofsingle-cone fillings with RoekoRSA sealer. Oral Surg Oral Med Oral Pathol OralRadiol Endod 2006;101:662–7.
4. Kont Çobankara F, Adanır N, Belli S, Pashley DH. A quantitative evaluation of apicalleakage of four root-canal sealers. Int Endod J 2002;35:979 – 84.
5. Wu M-K, Tigos E, Wesselink PR. An 18-month longitudinal study on a new silicon-based sealer, RSA RoekoSeal: a leakage study in vitro. Oral Surg Oral Med OralPathol Oral Radiol Endod 2002;94:499 –502.
6. Ørstavik D, Nordahl I, Tibballs JE. Dimensional change following setting of root canalsealer materials. Dent Mater 2001;17:512–9.
7. Miletic I, Devcic N, Anic I, Borcic J, Karlovic Z, Osmak M. The cytotoxicity of RoekoSealand AH Plus compared during different setting periods. J Endod 2005;31:307–9.
8. Bouillaguet S, Wataha JC, Lockwood PE, Galgano C, Golay A, Krejci I. Cytotoxicity andsealing properties of four classes of endodontic sealers evaluated by succinic dehydroge-nase activity and confocal laser scanning microscopy. Eur J Oral Sci 2004;112:182–7.
9. Al-Awadhi S, Spears R, Gutmann JL, Opperman LA. Cultured primary osteoblast viabilityand apoptosis in the presence of root canal sealers. J Endod 2004;30:527–33.
0. Bouillaguet S, Wataha JC, Tay FR, Brackett MG, Lockwood PE. Initial in vitro biolog-ical response to contemporary endodontic sealers. J Endod 2006;32:989 –92.
1. Monticelli F, Sword J, Martin RL, et al. Sealing properties of two contemporarysingle-cone obturation systems. Int Endod J 2007;40:374 – 85.
2. Brackett MG, Martin R, Sword J, et al. Comparison of seal after obturation techniquesusing a polydimethylsiloxane-based root canal sealer. J Endod 2006;32:1188 –90.
3. Wu M-K, Fan B, Wesselink PR. Diminished leakage along root canals filled with gutta-percha without sealer over time: a laboratory study. Int Endod J 2000;33:121–5.
4. ElAyouti A, Achleithner C, Löst C, Weiger R. Homogeneity and adaptation of a new
gutta-percha paste to root canal walls. J Endod 2005;31:687–90.ealing Ability of New Polydimethylsiloxane-based Root Canal Filling Material 207