Emax Crowns have this brand name to signify that they provide maximum aesthetics. They are sufficiently strong to allow you to eat the foods that you can eat with natural teeth, but definitely not as strong as zirconium crowns. So with both the crowns, you can use those teeth for biting the foods that you're naturally eat otherwise. But if you want maximum strength and sufficiently good aesthetics, you can opt for zirconium crowns because the latest zirconium Crowns, when fabricated properly and layered with the appropriate ceramic, can give excellent aesthetics. I can tell this from my own personal experience that a well fabricated zirconium crown is indistinguishable by a lay man in ambient light or natural sunlight. Proper shade selection is an important step and we prefer to do it in concordance with the patient's opinion, because for a front tooth and especially in a female patient we cannot expect any lack of perfect establishment of aesthetics. Regards