Special tray material

 The special tray material I have encountered come in the light cured and chemical cure varieties. The light cured variety is rougher and are premade in thin sheets. Therefore they are simpler to use as an acrylic baseplate for wax rims/bite blocks and the wax can stick to the rougher surface and they can be made thin to leave space to set teeth. They also seem stronger in thinner sections compared to the chemical cure variety. One thing to note is hat although the chemical cure variety comes out a lot smoother and may be nicer for the patient, if it is heated, it tends to soften and melt slightly. This can be beneficial as adjusting it on a trimming wheel, the excess slumps together and can be peeled off compared to light cured tray material which will produce a lot more dust. However, the downside is that for denture impressions, heating the tray in a flame is ill advised as the tray will soften and become deformable. For crown and bridge, and other impressions where the extensions aren't vital, I think this material is quite adequate and may be more comfortable for the patient but for denture impressions I would prefer the light cured material.