Alloi Metal-Ceramic utk Prosthetik

Pengertian

• Logam paduan untuk bangunan prostetik yang mampu mengikat keramik dengan ikatan kimiawi dari hasil difusi -jerapan lapisan tipis oksida antara logam paduan dengan keramik dengan tujuan utama estetika

Dalam PFM terdiri 3 substansi yang saling berikatan secara kimiawi yaitu logam, lapisan tipis oksida dan keramik

CerM MO

Kegunaan alloi dengan porselin difusi dalam logam(PFM)

• Bangunan restorasi dengan veneer-porcelain• Restorast all-metal

• Implant device• Orthopaedic device

EstetikaNon corrosive

Jenis material

• High Noble Alloy (contoh: Gold alloy) - Gold-palladium-platinum alloy - Gold-palladium-silver alloy - Gold-palladium alloy• Noble Alloy (contoh: Palladium alloy) - Palladium-silver alloy - Palladium-gallium-silver alloy - Palladium-gold alloy - Palladium-gold-silver alloy - Palladium-copper alloy - Palladium-cobalt alloy

• Base Metal Alloy (contoh ) - Nickel – chromium alloy - Nickel – chromium- berrylium alloy - Cobalt – chromium alloy - Cp Titanium - Titanium-aluminum-vanadium

Persyaratan khusus PFM

• Temp. melting alloi hrs lbh tinggi dp firing tempe-rature keramik

• Mampu menahan creep atau sag pada suhu melting alloi / firing temperatur keramik

• Koef. ekspansi termal (CTE) compatibel thd porselin• Mampu mengikat porselin• Memp. stiffness tinggi (adanya flexing dari alloi

menyebabkan porselin fraktur• Tidak boleh ter stain atau discoloration

Sifat khusus High Noble Alloys PFM

• Melting range: 1149 – 1304 C• Density : 13.5 – 18.3 gr/cm3• Castability : easy to cast• Hardness & workability : 182 – 220 VHN, extremely

easy to work• Percent elongation : 5 – 20%• Porcelain bonding :oxide layer assists in chemical

bonding• Sag resistance : to withstand temp. of as high as 950

C

Sifat khusus Noble Alloys PFM

• Melting range : 1155 – 1304 C• Density : 10,5 – 11,5 gr/cm3• Castability :do not cast as well than high noble• Hardness & workable : 189 - 270 VHN, extremely

easy to work• Percent elongation : 10 – 34% • Porcelain bonding : with base metal (Sn, In, etc) are

added to assists porcelain bonding• Sag resistance : similar with high noble

Sifat khusus Base Metal Alloys

• Melting range : 1155 – 1304 C• Density : 7.8 – 8,4 gr/cm3• Castability : extremely technique sensitive• Hardness & workable : 175 – 360 VHN, extremely

difficult to work with• Percent elongation :10 – 28%, but not easily burnishable• Porcelain bonding : an adequate oxide layer is essential

for successful porcelain bonding• Sag resistance : far more stable at porcelain firing

temperature

Perlekatan logam pada porselin pada PFM

• 2 jenis ikatan utama: - chemical bonding

across the porcelain – metal interface pada Base metal melalui chromic oxide pada Noble metal melalui tin oksida and iridium oksida dll - Mechanical interlocking between porcelain and metal (nodules)

Pd-Ag alloy Porcelain

Hybrid layer PFM

4 µm 1 µm

nodules

Mechanism Bonding of PFM

• 1. Chemical bonding (oxides)• 2. Mechanism entrapment (nodules)

• 3. van der Walls force• 4. Compressive force

Discolorations• Greenish-yellow discoloration …….. high Ag - galium, geranium (2-9%)• Greenish ……………………………….. Cr• Dark brown – black ………………….. Cu• Dark ……………………………………. Co - galium, boron• Dark- grey …………………………….. Ni

• Opaque materials

Discolorasi ditutup dengan

• Anusavice KJ, 2003 Phillips’ Science Dental Materials, Saunders, USA

• Manappallil JJ, 2003 Basic Dental Materials, Jaypee Brother Pub, New Delhi