87th General Session & Exhibition of the IADR • 38th Annual Meeting of the AADR, Miami, Florida, USA, April 1-4, 2009

Objectives:

Materials and Methods:

Results and Discussion:

Conclusion: These data suggest that the MTBS values significantly decreased when the powder ratio was 0.2 because high viscosity prevented the penetration and

diffusion of monomers into radicular dentin. We concluded that the difference in powder/liquid ratio affected bondability of MetaSEALTM to radicular dentin.

MetaSEALTM (Hybrid Root SEAL; equivalent product to MetaSEALTM, marketed in Europe by Sun Medical, Japan) is a methacrylate-based endodontic sealer which consists of a powder-liquid system. The liquid is mixture of 4-META, HEMA, difunctional methacrylate monomer and photo-initiator. The powder components are zirconium oxide, silica and proprietary self-cure catalyst. The purpose of this study was to evaluate the effects on bondability of MetaSEALTM prepared with various powder/liquid ratio.

Table showed the mean MTBS at different powder/liquid ratio. The MTBS profiles showed a decreasing tendency with an increase in the powder ratio, while these were not statistically different between 0.08, 0.1 and 0.15 except the powder ratio of 0.2. Fracture analysis by light microscopy revealed a predominantly cohesive failure pattern within the sealer itself in all specimens tested.

The SEM observation resulted that all the specimens had hybrid layer of a 1-3 µm thickness with funnel-shaped tags of which length tended to be shorten with an increase of powder ratio. We considered this tendency was caused by poor penetration of oligomerized 4-META and HEMA to radicular dentin because of accelerated initial polymerization rate due to an increase in the amount of catalyst.

The extracted single-rooted human teeth were used and sectioned at the cement-enamel junction with a diamond saw. The experimental procedures were carried out as follows.

SEM observationAfter enlargement of root canal with a #80 H-file, root canals were endodontically treated

(15%-EDTA/2.5%-NaClO). They were filled with MetaSEALTM mixed at powder/liquid ratio of 0.08g/0.1g, 0.1g/0.1g (control : 1scoop/3drops), 0.15g/0.1g, and 0.2g/0.1g (2scoops/3drops), respectively. After storage in 100% humidity at 37°C water for 1month, specimens were cut horizontally against tooth axis using SiC-paper and sliced into 0.8mm thick. Bonded surface observed under scanning electron microscopy (SEM) after treatment with hydrochloric acid and NaClO.

MTBS testingAfter enlargement of up to 1.7mm diameter of root canal with a peeso reamer, root canals were

irrigated with combination of EDTA/NaClO. Canals were filled with MetaSEALTM of the above mixing ratio, and stored at 37°C water for 1month. Specimens were cut horizontally against tooth axis and sliced into 0.7mm thick. Slices were trimmed to create dumbbell-shaped specimens with a cross-sectional area of 1mm2, and microtensile bond strength (MTBS) was measured at a cross-head speed of 1mm/min. After testing, fractured specimens were analyzed under a stereomicroscope to determine the type of failure. The data were statistically analyzed by one-way ANOVA and Turkey’s test (p=0.05).

SolubilitySolubility of MetaSEALTM prepared with various powder/liquid ratio was tested according to ISO

6876:2001(E) standards.

#2334 Influence of powder/liquid ratio on bondability of a methacrylate-based sealer Sayuri Iwasaki1, Tatsuya Ori1, Shogo Wakamatsu2, Tadashi Kawashima3, Norihiro Yamamoto2, Kiyoshi Matsushima3 and Takuji Ikemi2

1 : Sun Medical Co., Ltd., 2 : Department of Dental Caries Control and Aesthetic Dentistry, Nihon University School of Dentistry at Matsudo, 3 : Department of Endodontics, Nihon University School of Dentistry at Matsudo

MetaSEALTM

(Parkell Inc., U.S.A)

MTBS testing and SEM observation

Solubility increased with an increase in the powder ratio. Solubility of 2.0 powder ratio was higher than those of other mixing ratio and became 11 times compared with that of control. These data indicated that solubility of various ratio satisfied ISO requirement (< 3.0%).

Solubility

Table physical properties of MetaSEALTM prepared with various powder/liquid ratio

MetaSEALTM

Powder / Liquid ratio ( g / g )Distance from apex(mm)

SEM

0-1

2

5

MTBS (MPa)

Solubility (%)

22.0 ± 5.6 a

Cohesive failure : 100%

0.08 / 0.1 0.15 / 0.10.1 / 0.1(1 scoop / 3 drops)

0.2 / 0.1(2 scoops / 3 drops)

0.19

21.4 ± 4.9 a

Cohesive failure : 100%

0.25

18.8 ± 4.1 a

Cohesive failure : 100%

0.68

13.1 ± 3.0 b

Cohesive failure : 100%

2.66

Hybrid Root SEAL(Sun Medical, JAPAN)

MT

BS

(MP

a)

Powder (g)

5

10

15

20

25

30

0.05 0.1 0.15 0.2 0.25

Fig.1 MTBS value at various powder/liquid ratio.

So

lub

illit

y (%

)

Powder (g)

0

0.5

1

1.5

2

2.5

3

0.05 0.1 0.15 0.2 0.25

Fig.2 Solubility at various powder/liquid ratio.

Cement-enamel junction

• Enlargement• Endodontic treatment

(15% EDTA : 2min , 2.5% NaClO : 2.5min)

Slice Microtensile testing(C.H.S : 1mm/min)

Cutting

ProcedureMTBSMTBS

• Embedding• Bond to acrylic resin

Filling with MetaSEALTMCutting

Stored for 1month(100%humidity at 37˚C)

Acrylic point (ø1.2mm)

Trimming(1mm2)

Peeso reamer #6(ø1.7mm)

5mm

H-file (#80)

Cement-enamel junction

• Enlargement• Endodontic treatment

(15% EDTA : 2min , 2.5% NaClO : 2.5min)

ProcedureSEM observationSEM observation

SEM observationFilling with MetaSEALTMCutting

Stored for 1month(100%humidity at 37˚C)

Gutta-percha point

• Slice• Polishing

Treatment(6N HCl : 5sec , 1% NaClO : 5min)