sessions to maximize treatment substantivity and exposure time subjects was refrained from eating or drinking for 30 minutes following each chewing session the participants returned their unused gum so that usage levels and compliance can be estimated the chewing gums under evaluation were provided by the sponsor in blank coded packaging the following products were tested 1 flavored sugarless chewing gum no 1 containing 0 50 mg zinc acetate per piece with no tooth brushing 2 flavored sugarless chewing gum no 2 containing 0 50 mg zinc acetate per piece with no toothbrushing 3 tooth brushing with no chewing gum control the chewing gums used in this study was prepared in accordance with good manufacturing procedures gmp at the sponsor 39 s food approved iso standardized facility the gums contained nutrasweet u00ae and the standard warning to phenylketonurics was on the packaging the final exam for each subject was scheduled at exactly 48 hours following their baseline exam subjects continued to follow the same 48 hour sequence for each of the 3 cross over periods in order to minimize any effect arising from the time of day that the chewing gum was last used after each 2 day trial period the subjects were scored first for oral health and then for dental plaque in order to determine the amount of plaque that formed on the teeth all exams and cleanings were performed by experienced licensed dental personnel using accepted methods of infection control in compliance with osha 39 s standard for occupational exposure to bloodborne pathogens 29 crf 1910 1930 and indiana public law 123 1988 sterile instruments disposable rubber gloves and procedural masks were used for each exam in order to protect both the dental staff and.