tissue stop
A small acrylic or wax extension on a custom impression tray that contacts the mucosal surface to maintain a uniform, controlled thickness of impression material.
Full Definition
A tissue stop is a deliberately placed protrusion on the fitting surface of a custom impression tray designed to rest against a stable mucosal area (often the palate or edentulous ridge), ensuring the tray is seated at a consistent distance from the tissue. This prevents the tray from bottoming out and creating an uneven thickness of impression material, which could distort the resultant model. In full-arch impressions for complete dentures, tissue stops are typically placed in the posterior palatal region. Laboratory technicians fabricating custom trays must incorporate tissue stops as specified, and work orders should clearly distinguish their location. Editors may encounter this term in fabrication instructions and should not mistake it for a 'relief area,' which is a concavity, not a protrusion.
Usage
Usage note: Do not confuse 'tissue stop' (a protrusion maintaining space) with 'relief area' (a concavity relieving pressure). Both appear on custom trays but serve opposite mechanical purposes.
In Context
- "Three tissue stops were incorporated into the custom tray to standardise impression material thickness across the arch." — Custom tray fabrication instruction
- "The absence of tissue stops on the returned tray was flagged as a fabrication error in the QC audit." — Quality assurance report