One of the drawbacks of at home whitening vs in office is the protection of soft tissues such as the gums are sacrificed. Filling the trays should be with the absolute least amount of gel necessary to evenly displace over the teeth, Many times, overfilling the trays will lead to leakage onto the gums. After placing the trays always be sure to use a tissue to remove any excess materials. Trays should also add protection by adapting well to the teeth and gumline with "wells or bubbles" on the teeth to hold the gels in. Perhaps a new tray should be made up if there is constant leakage of material.Placing the gel on the teeth and then inserting the tray can be a recipe for disaster as the gel can be pushed off the teeth onto the gums during insertion. I therefore, would not recommend to try it. Lastly, there are many different gels and systems out there. If one is very irritating to the gums, discuss other options with your dentist for a better alternative for your situation.Good luck!
