degassing
Pronunciation: dee-GAS-ing
A pre-oxidation firing cycle applied to metal alloy frameworks in the dental laboratory to clean the surface and promote porcelain bonding.
Full Definition
Degassing is a controlled heat treatment process performed on cast metal alloy copings or frameworks prior to porcelain application. During this cycle, surface contaminants, casting residues, and trapped gases are volatilised in a dental furnace, and a controlled oxide layer is formed on the metal surface. This oxide layer is critical for chemical bonding between the metal substructure and the overlying porcelain. Degassing parameters, including temperature, time, and atmosphere, are material-specific and must be documented accurately in laboratory process records. Editors should not confuse degassing with 'oxidising,' which is a related but separately named step in some laboratory protocols.
Usage
Usage note: Spell as one word, no hyphen. Do not conflate with 'oxidising cycle,' which may appear as a separate step in the same workflow.
In Context
- "The metal coping underwent a degassing cycle at 980 °C before the first opaque layer was applied." — Dental laboratory process log
- "Skipping the degassing step can result in porcelain delamination at the metal–ceramic interface." — Dental laboratory quality control manual