A review of the record demonstrates that there existed a rational and valid line of reasoning by which the jury could find that defendant Dr. Kurpis committed dental malpractice and that such malpractice constituted a proximate cause of plaintiff's injuries when he failed to install an upper roundhouse bridge to match the lower roundhouse bridge that had been installed in plaintiff's mouth. (See, Cohen v Hallmark Cards, 45 N.Y.2d 493; Mortensen v Memorial Hosp., 105 A.D.2d 151.) The parties' expert testimony concerning the source of plaintiff's jaw pain created a factual issue which was resolved by the jury. Finally, no basis exists to disturb the jury's finding with respect to plaintiff's comparative negligence, particularly where plaintiff declined to follow the full course of treatment and work recommended (see, Nallan v Helmsley-Spear, Inc., 50 N.Y.2d 507, 516-517).
Concur — Carro, J.P., Rosenberger, Kupferman, Kassal and Smith, JJ.