Does emax crowns requires no removal of tooth structure or very minimal tooth structure?

Depends: It depends more upon the condition of the tooth and your mouth and little to do with the type of material used as long as it can be bonded. Check with your dentist who can see your condition for a better answer.

About the same: Most cosmetic full crowns require about the same amount of removal of tooth structure to insure ideal cosmetics and strength. The range is between 1 and 2 millimeters. The most conservative crowns from the point of view of removal of tooth structure are made of gold. Often, a partial-coverage restoration can be made using either ceramics or gold. This preserves even more tooth structure.

Bruxzir crown: A bruxzir crown could be what you are looking for because it is white. Some tooth structure will have to be removed though. A quote from bruxzir.Com. "shoulder preparation not needed, feather edge is okay. It is a conservative preparation similar to full-cast gold, so any preparation with at least 0.5 mm of occlusal space is accepted. Minimum occlusal reduction of 0.5 mm; 1 mm is ideal.".

EMax: Emax porcelain is similar to bruxir but is not the same. Structural strength of emax is very close to enamel and has a wear rate that is also similar. Bruxir is significantly stronger and will be more abrasive to opposing teeth. Both materials can be considered enamel replacement materials that means minimal reduction of approximately .7mm. Reduction still needs to be done as to not over contour.