Base Metal Alloy
Also written as: BMA — Base Metal Alloy
A category of dental casting alloy composed primarily of non-precious metals—most commonly nickel-chromium, cobalt-chromium, or titanium—used when high strength and lower cost are prioritised over biocompatibility considerations.
Full Definition
Base metal alloys (BMAs) in dentistry contain less than 25 wt% noble metals and derive their properties from elements such as nickel, chromium, cobalt, molybdenum, and beryllium. Chromium confers corrosion resistance through passive oxide layer formation; nickel provides ductility and toughness. Beryllium-containing alloys require special safety precautions and must be labelled accordingly in laboratory and clinical documentation. Editors should flag unlabelled use of nickel-chromium alloys in manuscripts involving patients with known metal hypersensitivities. The ISO 22674 classification uses the term 'predominantly base metal' for these alloys. 'Base metal alloy' and 'non-precious alloy' are acceptable synonyms in editorial contexts; 'base alloy' alone is non-standard.
Usage
Usage note: Prefer 'base metal alloy' over 'non-precious alloy' in ISO-aligned contexts. 'Semi-precious alloy' is an obsolete commercial term; flag and replace with the appropriate ADA/ISO category.
In Context
- "The cobalt-chromium base metal alloy framework demonstrated adequate rigidity for the four-unit fixed partial denture." — Prosthodontics clinical case description
- "All manuscripts reporting nickel-containing base metal alloys should include a biocompatibility statement addressing the potential for hypersensitivity reactions." — Journal author guidelines