Poor Bond of Impression Material to the Tray

No tray adhesive used. +

Use tray adhesive for all types of impression trays and apply adhesive on bottom and on inner sides of the tray, including gauze of dual-arch trays. Polyethers and VPS impression materials have different and specific tray adhesives. Make sure that the proper tray adhesive is being used for the impression material.

Inadequate layer of tray adhesive. +

Follow manufacturer`s instructions for use for application and drying time.

Smear layer on custom trays. +

Remove smear layer with acetone, grinding instruments or sandblast. Always make sure to clean trays after mouth try-in.

Tray distortion upon removal. +

Use stiff and rigid trays and make sure the tray fits well. Ensure the impression tray is the proper size prior to taking the impression. Remove the impression along the axis of the prepared tooth.

Detachment of tray material from tray during carving (2-step technique). +

Apply adhesive on bottom and on inner sides of the tray. Use a sharp carving instrument to minimize stress at the interface of tray material and tray. Otherwise, tray material could detach from the tray unnoticed and causes deformation.