Help! I have 2 root canals (done about 15 years ago) out of my 4 front teeth that I am getting crowns for. Lots of old and new cavities in between and in back of teeth. I am currently wearing crowns temporarily, which are zirconia fused to porcelain.Is this the best material to use for my situation?Its the second set of crowns I've had. The first one were bad, we could see my real teeth through! Now the shade is still off (not matching my other teeth) and I am having doubts about what this lab and dentist is capable of.They say they can fix the shade (lighten up a bit) and add some to fill in the black triangles. I dont know what to think.