Part of the fabrication of an anterior bite plane appliance is assuring the fit. I hear lots of feedback that people struggle with them being too tight or floppy loose. Since switching to 1.5 mm biocryl, the first thing I do is use Isofolan in my Ministar. It acts like die spacer, and since the Ministar is so accurate, it keeps the biocryl from being pulled into exact approximation to the model.
I am cautious when I trim the labial flange and begin at the junction of the cervical and middle thirds of the anterior teeth. Before placing the plane with composite I fit the biocryl in the patient's mouth. It is important to be able to place it with gentle hand pressure; do not force. If the biocryl will not go into place with gentle pressure, begin to trim back the labial side towards the incisal edge. I trim in about .5 mm layers and try in after each one, until I can seat the biocryl with gentle pressure.
At this point if the biocryl "feels" tight to the patient, I switch to hot water. My assistant will get me a bowl of water from our insta-hot, or you can microwave it. I drop the biocryl into the hot water for ten seconds, MAXIMUM. Pull out with cotton pliers and seat in the patient's mouth. Allow it to cool completely against the teeth. It may take several attempts to get it to feel comfortable. Remember they will loosen over time as they patient puts them in and out, so I advise my patients we want to begin with it on the tighter side.
The last thing I do is use an e-cutter to trim the biocryl that was pulled into the embrasures, and only if hot water does not do the trick. If you need this step, be judicious and take your time. If the biocryl is too loose and falls out, honestly the easiest thing is to make another and have a longer labial flange, as this usually occurs with short teeth that do not have a defined height of contour. In these cases it can also help to cover the entire arch or extend behind the canines.