Periodontal Tray Making Instructions for Dentists

Use .080 EVA or thicker/stiffer tray material
On model draw a line about 2 mm from the gingival margins.
Use a #1 burr to create a shallow trench on the model.
When vacuformed this creates a seal/dam on the tray. This promotes subgingival hydraulic pressure with the gel.
Trim trays 4-5 mm beyond the gingival margin, onto the soft tissue.

This will help people with dexterity problems who have a hard time brushing and flossing hard to reach places.
An effective cleaning therapy before and after dental procedures.