Adhesion casting

of polycarboxylate

cements

to dental

alloys

Sakai, D.D.S., D.D.Sc.,* Chikaaki Saito, D.D.S., D.D.Sc., * Yorhihiro D.D.S., D.M.Sc.*** Hisafumi Node, D.D.S., D.D.Sc.,** and Takao Fusayama, Tokyo Medical and Dental University, Tokyo, Japan

lh e popular polycarboxylate lating to the zinc ion and also ion. The cement also adheres tallic i0ns.l In this study, the adhesion four substitute alloys used for zinc phosphate cement. MATERIALS

AND

cement, presented by Smith’ in 1968, sets by cheadheres to tooth structure by chelating to the calcium to various dental alloys by chelating to the other meof commercial polycarboxylate cements to a gold and dental cast restorations was compared with that of a

METHODS

Cylindrical specimens, 9.44 mm. in diameter and approximately 5 mm. in height, were made by casting five commercial dental alloys used in Japan (Table I). One end of each was polished with wet abrasive paper, up to No. 2000, for the adhesion test. Four polycarboxylate cements were compared with a zinc phosphate cement (Table II). An acrylic resin rube, 10 mm. inner diameter and 15 mm. high, was placed on a glass plate, filled with one of the cements mixed to the standard consistency, and covered with a glass plate (Fig. 1, left). To retain the cement, the acrylic resin tube had many depressions prepared on its inside wall with a round but-. For hanging the tensile load, a wire bar was inserted horizontally midway through the tube containing the cement. After one day in storage, the cement block was attached with the same cement to the polished end of the alloy specimen. The polished end had been cleaned with 70 per cent alcohol and had dried (Fig. 1; right). The cemented specimen was kept under a load of 1 Kg. for 10 minutes in a thermostatic humidor regulated at 37O C. *Lecturer. **Instructor. ***Professor of Operative Dentistry. 543

J. Prorthet. Drnt. May, 1976

544

Suit0

et al.

Table

I. Alloys used Brand names

Manufacturers

Progold Miro-Silver Cast Well M. C. Type III Suncolium U. S.

Hayashi Metallurgical Laboratory G-C Dental Industrial Co. G-C Dental Industrial Co. Au IO, Ag 15,Cu 10, Pt 3, Pd 2 Sankin Industry Co.

Alloys Copper Silver-tin-zinc Silver-palladium Gold Nickel-chromium

Table

II. Cements

tested

Brand names

Cements Polycarboxylate cement Zinc phosphate cement

Carlon Carbocement Carbolit Poly-F Crown-bridge and inlay cement

BatchNo. 17413 I VR5 NL22, PA22 BG 19

Manufacturers Sankin Industry Co. Shofu Dental Mfg. Co. G-C Dental Industrial Co. Amalgamated Dental Co. G-C Dental Industrial Co.

Powder:liquid (Gm.:ml.) -1.5:l.O 1.4:l.O 1.5:l.O 1.5:1.4 1.5:0.5

Table Ill. Adhesive strengths to various dental alloys of a polycarboxylate cement compared with that of a zinc phosphate cement in kilograms per square centimeter* Alloys Copper Silver-tin-zinc Silver-palladium Gold (type III) Nickel-chromium

)

Polycarboxyfate cement (Carlon) 13.31(2.53) 9.39 (2.81) 5.34 (2.87) 3.64 (2.24) 12.93(3.59)

1

Zincphosphate cement (G-C) 2.89 (0.83) 2.27 (0.84) 0.87 (0.59) 0.96 (0.57) 1.21 (0.57)

*Standard deviations are in parentheses. and more than 95 per cent relative humidity. The assembly was then immersed in distilled water at 37’ C. for a week. For the tensile strength test, the alloy cylinder was held in a vise and lead balls were placed into a bucket that was hung on the wire bar of the cement block (Fig. 2). A part of Michaelis’ test apparatus at a speed of 5.4 Kg. per minute was used to apply load. The adhesive strength was determined by measuring the load when the specimen separated from the cement block and by dividing the load by the area. This test was performed in a room at 23 & 2O C. and 50 + 10 per cent humidity. RESULTS Adhesive strength was determined after averaging the results of 10 tests for each assembly. Comparison of adhesive strengths of polycarboxylate cement and zinc phosphate cement. The adhesive strength of Carlon, representing all the polycarboxylate cements, was compared with that of zinc phosphate cement (Table III and Fig. 3). The polycarboxylate cement produced four to 12 times the adhesion of the zinc

i%%E %5

Adhesion

of cements

to alloys

545

Fig. 1. The cement block in an acrylic resin tube covered with glass plates (left) and a specimen of a cement block cemented to an alloy for the tensile test (right).

tube

Load bucket-

Fig. 2. The assembly for the tensile test. phosphate cement to all alloys tested. The adhesive strength of the polycarboxylate differed remarkably between alloys and was maximal to the copper, silver-tin-zinc, and nickel-chromium alloys. Its adhesion to the gold and silver-palladium alloys was inferior to its adhesion to the other alloys, but was four to six times greater than that of the zinc phosphate cement. All specimens cemented with zinc phosphate cement failed at the metal-cement interface. However, most specimens of nickel-chromium, copper, and silver-tin-zinc alloys cemented with polycarboxylate cements showed COhesive failure in the cements. Adhesive failure with the gold alloy occurred at the metal-cement interface. Only partial failure occurred with the silver-palladium alloy at the metal-cement interface. Compakon of polycarboxylate cements of dilferent brands. The adhesive strengths of the four polycarboxylate cements were compared using the gold, silvertin-zinc, and nickel-chromium alloys (Table IV and Fig. 4). The differences in adhesive strengths of the polycarboxylate cements to the gold alloy were not statistically significant. Adhesion to the silver-tin-zinc alloy showed statistically significant, but minor, differences between the cements. Adhesion to the nickel-chromium alloy

546

Suit0

J. Pwsthet. Dent. May, 1976

et al. Adhesion

@/cm2)

Cu alloy

Ag-Sn-Zn Ag-Pd

alloy

Au alloy (Type Ni-Cr

al 1OY

Zinc Ph. Cem.(G-C) Polycarboxylate (Carlon)

ml

Cem.

alloy

Fig. 3. The adhesive strength of a polycarboxylate compared with that of a zinc phosphate cement.

cement

to various

dental

casting

alloys

Table IV. Adhesive strengths to dental casting alloys of various brands of polycarboxylate

cement in kilograms

per square centimeter*

I Cements Carlon Carbocement Carbolit Polv-F

Gold (type III)

Allovs Silver-tin-zinc (Mire-Silver)

Nickel-chromium (Suncolium)

3.64 (2.24) 4.91(2.24) 5.03 (1.73) -

9.39 (2.81) 6.06 (3.43) 13.44 (5.46) -

12.93(3.59) 16.63(1.64)

*Standard devations are in parentheses.

showed no statistically significant difference between the fluoride-containing F) and the regular-type (Carlon) cements, though the mean was slightly with the former.

(Polygreater

DISCUSSION The adhesive strength of the polycarboxylate cement to all dental casting alloys tested was much greater than that for zinc phosphate cement. This result is in agreement with previous reports using gold alloy and stainless stee1.3-6 The adhesive strength of polycarboxylate cement to the three substitute alloys was maximal, but it was inferior for the gold and silver-palladium alloys. Polycarboxylate cement seems to form a stronger bond with chemically active substitute alloys than with chemically stable precious alloys. It had been reported that gold alloys are too inert to permit adhesion by polycarboxylate cement.2s 7 This study revealed, however, that its adhesion was four times greater than that of zinc phosphate cement, even to

Volume 35 Number 5

Adhesion Adhesion Alloys

cements

I

Carlon Au alloy

cements

to alloys

547

(kg/cm’) 15

.

’ c

Carbo-C.

10

5

0 1

of

1

-I

(Type JU Carbolit

74

I Ag-Sn-Zn

Carlon

allO]

(MiroSilver)

Ii-Cr all01 Suncolium~

Fig. 4. Comparison

Carbo-C.

I-y,

1

4

Carbolit

Carlon Poly-F of adhesive strengths of different

brands of polycarhoxylate

cement.

the gold alloy. Carboxylate cement seems to chelate to some extent even to gold alloys; this finding is also supported by previous reports.3y 5l 6 The differences in adhesive strength between the brands of polycarboxylate cement were generally slight or statistically insignificant. CONCLUSIONS The adhesive strengths of four commercial polycarboxylate cements to five dental casting alloys were compared with the strength of a conventional zinc phosphate cement. The following results were obtained. (1) The polycarboxylate cements showed adhesion that was four to 12 times greater than that of the zinc phosphate cement to all alloys tested. (2) The adhesive strength of the polycarboxylate cements was greater to the chemically active substitute alloys, such as the copper, nickel-chromium, and silvertin-zinc alloys. The adhesion of the polycarboxylate cements to the chemically stable gold and silver-palladium alloys was not as great, but was four to six times that of the zinc phosphate cement. (3) The difference in adhesive strength between the brands of polycarboxylate cement was generally slight or statistically insignificant. References 1. Smith, D. C.: A New Dental Cement, Br. Dent, J, 125: 381-384, 1968. 2. Smith, D. C.: A Review of Zinc Polycarboxylate Cements, J. Can. Dent. Assoc. 37: 22-29, 1971. 3. Fesseler, A., Fetterroll, D., and Reiss, H.: Mechanische und histologische Untersuchungen iiber Durelon, Dtsch. Zahnaerztl. Z. 26: 241-246, 1971.

548

J. Prosthet. Dent.

Suit0 et al.

May, 1976

4. Jendressen, M. D., and Trowbridge, H. 0.: Biologic and Physical Properties of a Zinc Polycarboxylate Cement, J. PROSTWET.DENT. 28: 264-271, 1972. 5. Ady, A. B., and Fairhurst, C. W.: Bond Strength of Two Types of Cement to Gold Casting Alloy, J. PROSTHET. DENT. 29: 217-219, 1973. 6. Moser, J. B., Brown, D. B., and Greener, E. H.: Short-term Bond Strengths Between Adhesive Cements and Dental Alloys, J. Dent. Res. 53: 1377-1386, 1974. 7. Griffith, J. R.: Recent Advance in Dental Cementing Media, Aust. Dent. J. 15: 288-293, 1970. TOKYO MEDICAL AND DENTAL UNIVERSITY No. 5-45, l-CHOME YUSHIMA, BUNKYO-KU TOKYO, JAPAN

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Adhesion of polycarboxylate cements to dental casting alloys.

The adhesive strengths of four commercial polycarboxylate cements to five dental casting alloys were compared with the strength of a conventional zinc...
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