I think the biggest missed expectation around 3D printed occlusal splints is its really not for every case. If the patient has advanced bruxism or TMJ its really not the solution for them, traditional materials and techniques are best.
CAD design is also critical, I've seen failures but most of the time its due to just poor design. For example not correctly balancing the biting force across the appliance which puts all the stress on one or two points or maybe even worse those areas are adjusted on a model/chair-side, thinning the part too much in critical areas. Lastly simply designing parts that are too thin, we recommend 1.5 to 2 mm of thickness on the occlusal surface of the appliance, the walls can be as thin as 1 mm. It seems logical but its easy to miss these things.
But being able to print a occlusal splint for around $4 is awesome, make two for under $10 and give the second one as backup. : )
We have some pretty good information on these products on our
indication or application page for occlusal splints and in our full step by step
application guide.
Let me know if this is at all helpful!