Dental Materials II - ADA Classification of Gold Alloys - By Noor Al-Deen M. Al-Khanati
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ADA Classification of Gold Alloys According to their Use: Type Name Brinell Hardness Number (BHN) Pure Gold (%) Melting Temperature Use Characteristics I Soft Gold Alloy 40 – 75 83% 950 – 1050°C (High) Simple Inlay Restorations § Used in cavities not subjected to high stresses, e.g. gingival cavities § HIGHLY DUCTILE & readily burnished II Medium Gold Alloy (Inlay Gold) 10 – 100 78% 630 – 970°C Large Inlay Restorations § Age Hardening § Most popular type for inlays III Hard Gold Alloy 90 – 140 76% 930 – 970°C Crown & Bridge § High Proportional Limit, resisting deformation IV Extra Hard Gold Alloy > 130 75% 870 – 980°C Partial Denture § Strength & resiliency required § LACK DUCTILITY V White Gold Alloy > 100 ---- ---- Crown & Bridge § Addition of platinum, palladium & silver § LESS DUCTILE than gold colored alloys § Less resistance to tarnish By: Noor Al-Deen M. Al-Khanati
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Syrian International University, College of Dentistry, Dental Materials Department.DMII, Classification of Gold Alloys
Transcript of Dental Materials II - ADA Classification of Gold Alloys - By Noor Al-Deen M. Al-Khanati
ADA Classification of Gold Alloys According to their Use: Type Name Brinell Hardness
Number (BHN) Pure Gold (%)
Melting Temperature
Use Characteristics
I Soft Gold Alloy 40 – 75 83% 950 – 1050°C
(High) Simple Inlay Restorations
§ Used in cavities not subjected to high stresses, e.g. gingival cavities
§ HIGHLY DUCTILE & readily burnished
II Medium Gold Alloy (Inlay Gold)
10 – 100 78% 630 – 970°C Large Inlay Restorations
§ Age Hardening § Most popular type
for inlays
III Hard Gold Alloy 90 – 140 76% 930 – 970°C Crown & Bridge § High Proportional
Limit, resisting deformation
IV Extra Hard Gold Alloy
> 130 75% 870 – 980°C Partial Denture § Strength &
resiliency required § LACK DUCTILITY
V White Gold Alloy > 100 ---- ---- Crown & Bridge
§ Addition of platinum, palladium & silver
§ LESS DUCTILE than gold colored alloys
§ Less resistance to tarnish
By: Noor Al-Deen M. Al-Khanati
