Let me answer your question in two parts ..the root canal and the crown. Any crown is relatively durable these days. The choice of Zirconia or any other tooth coloured crown is purely for superior aesthetics and not durability. So I don't think your crown is not the problem. As regards the second part of your question pain and swelling either your root canal done earlier is failing and may need to be repeated or you could be having a gum infection causing the symptoms. Hope this helps! See your dentist at the earliest and replace your crown only when your symptoms are completely gone

Yes of course zirconia crowns are durable and has very natural and cosmetic appearance, and they come with warranty also. But as far I could diagnose your problem, it is not related to crown or cap.If your tooth is getting loose and swollen gums,then there is some problem with the underlying tooth and the surrounding gums and the surrounding bone also. So you need to go for xray first, correct the underlying tooth problem first and then only go for zirconia crown.