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Asian Pac J Dent 2015; 13: 21-23.

A fundamental bonding technique for silver-palladium-coppergold alloy framework to be veneered with indirect composite
material
Hideyuki Imai, DMC, BA, MDS, PhD,a,b Hiroyasu Koizumi, DDS, PhD,b,c and Hideo
Matsumura, DDS, PhDa,b,cabc

Dental Technician School, Department of Fixed Prosthodontics, and Division of Advanced DentalTreatment, Dental Research Center, Nihon University School of Dentistry, Tokyo, Japan
Indirect composite material and metallic framework are chemo-mechanically bonded with adhesive systems.
This technical report describes a fundamental bonding technique for silver-palladium-copper-gold alloy. The
procedure reported here is applicable in fabrication of both single restorations and fixed dental prostheses.
(Asian Pac J Dent 2015; 15: 21-23.)
Key Words: adhesive, bonding, primer, silver-palladium-copper-gold alloy

Introduction
Restorations and fixed dental prostheses (FDP) made of silver-palladium-copper-gold (Ag-Pd-Cu-Au) alloy
are covered with Japanese social insurance schemes as one of the dental treatment options. Specifically,composite resin veneered castings made of Ag-Pd-Cu-Au alloy are applicable for anterior restorations,abutments and pontics of FDPs as one of the insurance-covered programs. It is critical for restorations thatbonding between indirect composite resin and metallic material is consistent and durable. A number of primers
for bonding casting alloys have been introduced into dental laboratory procedure.1-4 Although results of bondstrength testing are extensively reported, limited information is available about proper bonding technique infabrication of composite resin veneered restorations.1,2 This technical article describes a fundamental bondingtechnique of Ag-Pd-Cu-Au alloy to be veneered with tooth-colored indirect composite resin.

Technical Procedure
The following procedure shows a fundamental technique for fabrication of a maxillary single restoration to be
used for education in dental technology for restorations and fixed dental prostheses. The laboratory proceduresconsisted of the following steps.

1

2

3

1.

Prepare a wax pattern of the restoration on the stone die (Fig. 1).

2.

Cut back the facial surface of the wax pattern with a carving instrument (Fig. 2).

3.

Apply adhesive and sprinkle retentive beads 150-200 µm in diameter (Retention Beads II ss, GC Corp.,Tokyo, Japan) (Figs. 2, 3).

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44.

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Invest the wax pattern into a cristobalite mold material. Cast Ag-Pd-Cu-Au alloy (Castwell M.C.12, GCCorp.) into the mold with a centrifugal casting apparatus. Grind with rotary cutting instruments theperipheral area of the cut-back surface to remove retentive beads and to flatten the marginal veneering area.
Abrade the cut-back surface with 50-70 µm alumina (Hi-Aluminas, Shofu Inc., Kyoto, Japan) by means ofan airborne particle abrader (Jet Blast II, J. Morita Corp., Suita, Japan), to increase the bonding area andmechanically clean the surface (Fig. 4).

5.

Apply a single liquid priming agent (Alloy Primer, Kuraray Noritake Dental Inc., Tokyo, Japan) containing
both a thione monomer (6-(4-vinylbenzyl-n-propyl)amino 1,3,5-triazine 2,4-dithione, VTD) and aphosphate monomer (10-methacryloyloxydecyl dihydrogen phosphate, MDP) to the alumina-blasted
surface (Fig. 5, Table 1).

6.

Apply a single liquid bonding agent (Cesead N Opaque Primer, Kuraray Noritake, Dental Inc.) for bonding
between the framework and the opaque resin. Paint thin layers of opaque material, and expose the eachlayer to light from a laboratory polymerizing apparatus (Fig. 6). Characterize the opaque resin surface withthe appropriate shade of staining material.

77.

89

Place the dentin portion of the composite material (Cesead N) with a laboratory instrument, andpre-polymerize the resin material. Insert hair-lines and/or other characteristics again using the staining
materials before application of the incisal colored material. Add an enamel portion material (Cesead N) tothe incisal edges to reproduce a natural tooth-color appearance (Fig. 7).

8.

Light-polymerize the veneered materials in the laboratory light-polymerization. Grind and polish thesurface with rotary instruments (Smooth Cut, GC Corp.; Seiko Wheel, Seikosha, Kurume, Japan; and Sharp
Mini, Ohki Chemical, Hiroshima, Japan) (Fig. 8).

9.

Use a diamond paste (Dia Glaze, Yeti Dental-Shirokusu, Osaka, Japan) to achieve a microscopicallysmooth surface (Fig. 9).

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Table 1. Adhesive functional monomers and primers applicable for bonding composite resin and casting alloys
Compound (Functional group)

FormulaFor noble metal alloys (Ag-Pd-Cu-Au alloy, Gold alloy)
Thione (Thioxo group)=SThione (Thioxo group)=SThione (Thioxo group)=S
Disulfide (Disulfide group)-S-S-Monomer

Primer trade name (Manufacturer)

MTU-6
VTD
VTD
10-MDDT

Metaltite (Tokuyama Dental)
Prime Art Opaque Primer (Sun Medical)
Alloy Primer (Kuraray Noritake)
M. L. Primer (Shofu)

For base metal alloy (Co-Cr alloy, Ti-6Al-7Nb alloy, Titanium)
Phosphate (Phosphoryl group)-OP(=O)(OH)2
MDP
Phosphate (Phosphoryl group)-OP(=O)(OH)2
MDP
Phosphonic acid (Phosphonyl group) -P(=O)(OH)26-MHPA

Cesead N Opaque Primer (Kuraray Noritake)Alloy Primer (Kuraray Noritake)
M. L. Primer (Shofu)

Discussion
This technical article discusses chemo-mechanical retentive system between composite resin andAg-Pd-Cu-Au alloy. Mechanical retention is usually achieved through the use of retentive beads. As shown inFig. 4, retentive beads are removed from the cast metal framework along the peripheral area of the cut-backsurface. Although alumina particles were thereafter blasted, application of adhesive primer is recommended forenhancing marginal integrity of veneer-metal interface.

References
1. Matsumura H, Yoneyama T, Shimoe S. Veneering technique for a Ti-6Al-7Nb framework used in a resin-bonded fixed partial
denture with a highly filled indirect composite. J Prosthet Dent 2002; 88: 636-9.
2. Matsumura H, Mori S, Tanoue N. Fabrication of a maxillary posterior fixed partial denture with a type 4 gold alloy and adual-polymerizing indirect composite. J Oral Sci 2008; 50: 113-6.
3. Shimoe S, Tanoue N, Satoda T, Murayama T, Nikawa H, Matsumura H. Evaluation of single liquid primers with organic sulfur
compound for bonding between indirect composite material and silver-palladium-copper-gold alloy. Dent Mater J 2010; 29:25-9.
4. Imai H, Koizumi H, Shimoe S, Hirata I, Matsumura H, Nikawa H. Effect of thione primers on adhesive bonding between an
indirect composite material and Ag-Pd-Cu-Au alloy. Dent Mater J 2014; 33: 681-8.

Correspondence to:Dr. Hideyuki Imai
Dental Technician School, Nihon University School of Dentistry
1-8-13 Kanda-Surugadai, Chiyoda-ku, Tokyo 101-8310, Japan
Fax: +81-3-3219-8320 E-mail: imai.hideyuki@nihon-u.ac.jp
Copyright ©2015 by the Asian Pacific Journal of Dentistry.

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Accepted June 25, 2015.
Online ISSN 2185-3487, Print ISSN 2185-3479