ARAŞTIRMA (Research)

ABSTRACT ÖZET

Aim: The aim of this in vitro study was to compare the solubility levels of three different resin modified glass ionomer cements namely, Advance (Caulk/Denstply Inc., USA), Vitremer (3M Dental Products, USA) and Protec-Cem (R&D Vivadent, Liechtenstein).Material and Method: Ten specimens for each group, 15±1 mm Ø hole and 1mm thickness were prepared. With a the samples were dried and weighed (M1 value). Then the specimens were stored in deionized water for 7 days and than weighed again (M2 value). Lastly, the specimen were washed, dried and weighed again (M3 value). Solubility was calculated according to the formula Wsol= (M1–M3)/V where, Wsol is solubility of test material (µg/mm3) and V is volume of test material (mm3)The data were evaluated with Kruskal-Wallis and Mann Whitney U tests (p<0.05)Results: The test results showed that the solubility of three tested materials can be classified respectively from higher to lower as: Protec-Cem>Vitremer>Advance. Kruskal – Wallis test was used as there is a difference between the amount of solubility of the resin modified glass ionomer cements (x2=22,261, p=0,0). Mann-Whitney U test was used to compare cement groups and there was a significant difference. (p≤0,0).Conclusion: Within the limitations of this study, Advance cement showed better solubility properties

Amaç: Bu invitro çalışmanın amacı üç farklı resin-modifiye cam iyonomer simanın; Advance (Caulk/Denstply Inc., U.S.A.), Vitremer (3M Dental Products, U.S.A.) and Protec-Cem (R&D Vivadent, Liechtenstein) çözünürlük miktarlarının belirlenmesidir. Gereç ve Yöntem: Her grup için 15 mm çapında ve 1 mm yüksekliğinde örnekler hazırlandı. Örnekler kurutuldu ve tartıldı. (M1) Örnekler daha sonra 7 gün deiyonize su içerisinde bekletildi ve tartıldı (M2). Son olarak örnekler yıkandı kurutuldu ve tekrar tartıldı (M3). Çözünürlüğün hesaplanmasında şu formül kullanıldı; Wsol:(M1–M3)/VTest materyalinin çözünürlüğü (µg/mm3) V: silindirin hacmi (mm3). Verilerin istatistik değerlendirilmesinde Kruskal-Wallis ve Mann-Whitney U testleri kullanıldı (p<0.05).Bulgular: Test sonuçlarına göre materyallerin çözünürlük miktarları yüksekten düşüğe doğru şu şekilde sıralanmıştır, Protec-Cem>Vitremer>Advance. Rezin modifiye cam iyonomer simanların çözünürlük miktarların gruplararası karşılaştırması Kruskal-Wallis testi ile yapılmıştır ve siman grupları arası fark önemlidir, (x2=22,261, p=0,0). Tüm test grupları ikişerli olarak karşılaştırıldığında farklar istatistik olarak önemli bulunmuştur (p<0,05).Sonuç: Çalışmanın sınırlamaları içerisinde, Advance siman en iyi çözünürlük özelliği değerlerini vermiştir.

Hacettepe Dişhekimliği Fakültesi DergisiCilt: 31, Sayı: 3, Sayfa: 3-7, 2007

Evaluation of the Solubility ofResin-modified Glass Ionomer Cements

Resin Modifiye Cam İyonomer Simanların Çözünürlük Miktarlarının Değerlendirilmesi

*Nilüfer Çelebi Berİat DDS, PhD, **İbrahim tulunoğlu DDS, PhD

*Hacettepe University School of Dental Technology**Hacettepe University Faculty of Dentistry Department of Prosthodontics

KEYWORDS

Resin modified glass ionomer cements, Solubility

ANAHTAR KELİMELER

Resin-modifiye cam iyonomer simanlar, Çözünürlük

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INTRODUCTION

Various cements were used in dentistry with the purposes of conservative and restorative tooth treatment1. Cements should have not only conservative but also protective, luting, conceal-ing, isolating, repairing and painkilling features2.

Recently, glass ionomer cements have been popular due to their superior features, such as better biocompatibility, fluoride release and their preventive features against tooth decay3,4. Nevertheless, glass ionomer cements have some drawbacks such as not being long-lasting, having longer setting time, little fracture toughness due to loss of moist and low resistance to acidic attacks5,6. Such negative aspects of glass ionomer cements had already been taken into consideration and diminished by adding hydroxyl ethyl methacrylate (HEMA), Resin-Modified Glass Ionomer Cements were developed in 19927-10.

Compared to convertional cements, the early sensitivity to moist and dehydration, and resistance to solubility of resin -modified glass ionomer cements are reported to be better than those of glass-ionomer cements11-13. The solubil-ity of adhesive cements is vital in terms of clini-

cal applications. As the solubility of the cements increase, marginal integration, aesthetic and me-chanical problems arise14-17.. The solubility of the cements indirectly effects the overal success of the restorations being done.

The aim of this study was to compare the amount of solubility of resin-modified glass iono-mer cements containing different substances.

MATERIALS AND METHODS

This research was performed at the Kinetics Laboratories of Gazi University, Faculty of Engi-neering and Architecture.

The amounts of the solubility of resin-modi-fied glass ionomer cements, Group A: Advance (Caulk, Denstply Inc., USA) Group B: Vitremer (3M Dental Products, USA), Group C: Protec-Cem (R&D Vivadent, Liechtenstein) were de-fined (Table I).

The solubility experiments were performed in accordance with ISO 4049 standardization (1998)18. Stainless steel molds with 15 mm di-ameter and 1 mm thickness negative space were prepared (Figure 1). The jig was placed on a

TABLE I

The resin modified glass-ionomer cements of adhesive materials

MATERIAL COMPONENTS COMPANY

ADVANCEPowder : Strontium, aluminum,

fluorosilicate glassLiquid : OEMA acid ionomer

Caulk/Denstply, Inc.Milford, USA

VITREMERPowder: Fluoro-alumino silicate glassLiquid : Modified with methacrylate,

policarboxylic acid, HEMA3M Dental Products, St. Paul, USA

PROTEC-CEM

Powder: Ba-Al Fluorosilicate glass, Ytterbiumtrifluoride, Silica,

Liquid : Deionized water, HEMA, Dimethacrylate, Polyacrylic acid

R&D Vivadent,Liechtenstein

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glass slab and the cements were prepared in ac-cordance with the manufacturer’s suggestions, and were placed into the block. The surface was flattened and pressed with another glass slab un-til the excess material went away. At the end of the setting period, cement samples were taken off the block (Figure 2).

Two desiccators were used for the experi-ments. Calcium chloride granules were placed underneath the desiccators in order to eliminate the moist. The samples were placed into pre-num-bered glasses, and were placed into the desicca-tor and stored in an incubator at 37±1°C. Then, they were stored in the desiccator at 23±1°C for 1 hour and this process was carried out until there wasn’t more than 0,2 mg loss of weight.

The samples were weighed in an electronic balance analyzer (METTLER A J150, Switzer-land) (M1 values). Deionized water was added into the glasses and the samples were stored in

an incubator at 37±1 C for 7 days. The samples were dried with gentle air spray for 1 minute and were weighed (M2 values). The M2 value will not be used to determine the solubility value of the materials but it needs to be known for it is a tran-sition value between M1 and M3 values accord-ing to the ISO 4049 standardization18. Then the samples were placed in a desiccator at 23+1 C for 1 hour, and were weighed again (M3 values).

Solubility was calculated according to the for-mula:

Wsol=

Wsol: Solubility of test material (µg/mm3)

V: Volume of test material(mm3)

M1, M2, and M3: Weighed value oftest mate-rial (µg)

The data were evaluated with Kruskal-Wallis Variance Analysis, (p<0,05) and Mann-Whitney U test (p<0,05).

FIGURE 1

Stainless steel jig for preparation of samples

TABLE II

The statisticals results of the resin-modified glass ionomer cements (µg).

Minimum

(x10-2)Maximum

(x10-2) Mean(x10-2)

Std. Deviation(x10-2)

Advance -0,0148 -0,0020 -0,007540 0,0038350

Vitremer 0,01 0,02 0,0132 0,00487

Protec- Cem 0,00 0,02 0,0072 0,00461

FIGURE 2

Samples

M1-M3

V

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RESULTS

The base statistics for Advance, Vitremer and Protec-Cem groups which were tested in the study are presented in Table II. The test results showed that the solubility of three tested materi-als can be classified respectively from higher to lower as: Protec-Cem> Vitremer> Advance. As the evaluation of the data with Kruskal-Wallis Variance Analysis revealed that the differences between groups were statistically significant (x2=22,261, p=0,0), Mann-Whitney U test was used to compare cement groups and the differ-ences between all groups were statistically sig-nificant (p<0.05)) (Table III).

DISCUSSION

The evaluation of the solubility of adhesive cements is clinically important. As a result of ce-ment solubility, the deficiency in surface features and marginal accordance causes lack of accor-dance in restorations. Glass ionomer cements have been routinely used in clinical studies. How-ever, glass ionomer cements have some negative features such as early sensitivity to moist or wa-ter absorption.

Gemalmaz et al.19 evaluated the solubility of 4 different glass ionomer cements (Ketac-Cem, Fuji ionomer I, AquaCem, AquaMeron) in vari-ous time intervals. In their study, they found that the highest value of solubility obtained with sam-ples that contacted with water as soon as they were mixed.

Resin-modified glass ionomer cements have been developed so as to eliminate the negative features of glass ionomer cements. Because of

positive features such as being resistant to early moist contamination, easy to be placed and hav-ing decay-preventive features, resin-modified glass ionomer cements are considered attractive. Due to the rise in the application of these ce-ments and little amount of research in this issue, resin-modified glass ionomer cements were used in our research13, 20.

Yap et al.9 studied the amounts of the solu-bility of 6 different resin modified polyalkenoate cements which are polymerized with light (Vari-glass, Fuji Lining LC, Vitrebond, Vitremer, Pho-tac-Bond, Fuji II LC). In their studies, they ex-amined liner, base and restorative oriented forms in which Variglass resin-modified glass ionomer cement’s powder/liquid ratio is different. They pointed out that the highest value of solubility is in Vitrebond cement. They found that the value of solubility of Variglass restorative, that pow-der/liquid ratio is higher than Variglass liner, is also higher. They concluded that the amount of resin affects the amount of solubility.

Each of the three cements used in our research are chemically polymerizing type. Vitremer and Advance cements are in routine use in our clinic. On the other hand, Protec-Cem cement was first used in 1998 and it is relatively new cement and its features have not been fully examined yet.

Setchell et al21 used four different glass iono-mer cements in their study (Chemfill, Aqua-Cem, Ketac-Cem, Chelon) and they concluded that luting cements show less solubility than restor-ative-based cements. The resin-modified glass ionomer cements used in our study were luting cements.

Toledano et al.22 studied the amounts of solubility of two restorative-based composite resins (Z 100, Prodigy), four polyacid-modified resin composites (Compoglass, Compoglass F, Dyract, Dyract AP) and two resin-modified glass cements (Vitremer, Fuji II LC) which are light polymerized. They found that the least solubility was in Compoglass and Compoglass F materials, and that Dyract, Dyract AP, Z 100 and Prodigy

TABLE III

The evaluation of the differences between test groups with Mann-Whitney U tests.

Vitremer Protec- Cem

Advance 0.000 0.000

Vitremer 0.009

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consequentially followed them. They also real-ized that the highest solubility was in Fuji II LC and Vitremer because of matrix structure. The common material used both in this survey and in our research is Vitremer. Vitremer is widely used and has several variants. The Vitremer that Toledano et al22 used in their research is the re-storative type of Vitremer. The one used in our research was luting type. According to the study carried out by Toledano et al.22 Vitremer showed a high solubility. Nevertheless, as it was afore-mentioned, restorative materials show a higher solubility than their luting cement variants21.

Within the limits of this study it can be con-cluded that the solubility of three tested materi-als can be classified respectively from higher to lower as: Protec-Cem> Vitremer> Advance.

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CORRESPONDING ADDRESS

Nilüfer ÇELEBİ DDS, PhDHacettepe University School of Dental Technology Sihhiye 06100 Ankara, Turkey

Tel:+90 312 305 1587 Fax: +90 31) 311 3741 E-mail: nberiat@hotmail.com