In a dental malpractice action, defendant appeals from an order of the Supreme Court, Kings County, entered April 25, 1980, which denied his motion pursuant to CPLR 3012 (subd [b]) to dismiss the action for failure to serve a complaint. Order reversed, on the law, with $50 costs and disbursements, and motion granted. The delay of more than one year in serving a complaint after demand was made was not adequately explained by counsel’s affirmation, which noted his clients’ residence in the State of New Jersey and their inability to recall the exact dates of treatment. Moreover, the merit of the claim was not established by mere submission of an unsworn dentist’s report describing plaintiff Ida Rothstein’s injuries without establishing their cause. Under the circumstances, dismissal was required (see Barasch v Micucci, 49 NY2d 594). Lazer, J. P., Mangano, Gibbons and Cohalan, JJ., concur.