“What is the best crown for front teeth?”

Full porcelain or ceramic preferably.

From a strictly cosmetic perspective, I would use e.Max. From an increased strength and adequate cosmetics perspective, I would use BruxZir Anterior.

Most likely an Emax crown unless you have an occlusal interference...your dentist will know.

That depends on a lot of factors. You smile line, your bite, etc. Generally speaking, E-Max crowns are very esthetic, or if the situation requires strength layered Zirconia.

Depends on the color of the tooth. Some teeth are very dark brown even black from past root canals, in that case full zirconia or porcelain fused to high noble metal is best. If your tooth is a natural color all porcelain crowns are the most esthetic options in the anterior/front of the mouth. Function also comes into play, if a patient is a heavy grinder or clencher a porcelain fused to high noble where the lingual/back of crown is metal so you don't wear off the enamel of the teeth touching that crown may be prescribed. Also patients who grind or clench should also be prescribed an occlusal guard after crown placement no matter the choice of crown to protect the teeth from their habits.