The Court of Appeals has found in Rivera v Anilesh ,2007 NY Slip Op 05134 , Decided on June 12,  2007 , that a dentist’s habit [his regular procedure] of injecting anesthetic, is admissible to show lack of negligence.

"In this malpractice action by a patient against her dentist, we are asked whether the dentist’s routine procedure for administering an anesthetic injection is admissible as habit evidence supporting an inference that the same procedure was used when treating the patient. Based on the record before us, we conclude that the habit and routine practice testimony is [*2]admissible."

"In Halloran v Virginia Chems. (41 NY2d 386, 391 [1977]), we explained that "evidence of habit has, since the days of the common-law reports, generally been admissible to prove conformity on specified occasions" because "one who has demonstrated a consistent response under given circumstances is more likely to repeat that response when the circumstances arise again." The applicability of this doctrine is limited to cases where the proof demonstrates "a deliberate and repetitive practice" by a person "in complete control of the circumstances" (id. at 392) as opposed to "conduct however frequent yet likely to vary from time to time depending upon the surrounding circumstances" (id. at 389). If these conditions are satisfied, "a party should be able, by introducing evidence of such habit or regular usage, to allow the inference of its persistence . . . on a particular occasion" (id. at 392). "

The case goes on, and makes for good reading.  Will this apply to Legal Malpractice too?