I have a broken cusp on a second molar, tooth #18. There is no decay on the tooth and it doesn't need a root canal treatment.\n\nA dentist who was recommended to me suggested fixing it with an onlay, which she described as a 3/4 crown. She will use either Cerec with Celtra Duo, a zirconia reinforced lithium disilicate material (milled and polished method), which has a flexural strength of 210 MPa. Or, I can get a lab made crown using traditional dental molds for the impression, with IPS e.Max, which has a strength of 360 MPa.\n\nWhen I asked about zirconia, ideally the translucent kind, which I understand is the strongest tooth-like ceramic (with a 600-750 MPa), this dentist said that she doesn't use zirconia.\n\nIf I have this dentist do my onlay, I am leaning towards e.Max because it has a longer track record and it is stronger than the Celtra Duo (when using the milled and polished method).\n\nPlease note that when Celtra Duo is glazed and fired, its strength increases to 360 MPa. However, this dentist doesn't fire the crowns. Overall, I am worried about trying either of the recommended ceramic materials because I think they are too weak and will break in a short time, if used on a second molar.\n\nTo complicate matters, I live in the Boston area where the cost of dental services is astronomically high and I have no dental insurance. So, I want the onlay to last as long as possible for both cost considerations and because I don't want to risk repeatedly drilling on the tooth, which might cause me to need additional dental treatment.\n\nCould there be a reason why a dentist would recommend weaker ceramic materials for a second molar when those materials are usually used for crowns in the front of the mouth? Should I go with the e.Max option? Or, should I find a dentist who uses zirconia for second molar crowns?\n\nAny information or advice on this matter would be greatly appreciated.