Poor quality. He would replace a defective molar crown that failed after 1 month -- only if I would pay for new material. Another dentist found Zaffer's crown material was only strong enough for an incisor and too weak for a molar. I had to pay the new dentist for a replacement crown with no insurance help. Zaffer did not reply to my request for a refund and has failed to respond to Humana's request for information about the case.