Modified custom tray.

The use of a custom tray is highly desirable for accurate impression making in situations with multiple abutments. This article describes a modified custom tray fabrication method using autopolymerizing acrylic resin. The custom tray is fabricated by intraoral relining with autopolymerizing resin that is polymerized extraorally. The final impression is obtained during the same session after tray polymerization at 100 degrees C for 5 minutes. Relined areas are refined by trimming excess resin with burs of a known diameter to create a 2-mm clearance for the elastomer. For areas with subgingival finish lines, only 0.5 mm of resin is removed to direct the elastomer into the gingival sulcus. The procedure is time-saving because it reduces the need for a retraction cord and minimizes inaccuracies that would necessitate another impression.