With Ivoclar's new 14:50 second "Fast Fire" the recommendation is that you use spray glaze. Now I have been the biggest hater of the spray glaze but I may have to eat my words. When I was in Australia a few weeks ago, an Ivoclar rep and I got into a discussion about the spray glaze and my dislike for it. He showed me his technique.
So I took two crowns and figured, lets give this a shot. One will be done with spray glaze and one will be done with the paint on glaze.
The technique: Give a quick 2 second burst, wait 3-4 seconds, another 2 second burst, wait another 3-4 seconds you want to do this till the entire surface is covered and when it dries, you should have a white frosty appearance.
The appearance of the crown with the spray glaze as mentioned should be frosty: With the paint on glaze, use as thin of a glaze as possible. Do not do a thick layer as it will appear bubbly and have the orange peel appearance: The end result- you decide. For me, I see no appreciable difference in the quality of restorations. To me they appear to be very similar. Can you tell which is which? The spray glaze is slightly better but I don't know if its worth the extra material that you waste. To me, the end result of both is similar with the spray glaze with a slight advantage. Bottom line is that if you love the paint on glaze, you can use it in the restorations at the 14:50 cycle without too much worry.