A New York dentist is pleading not guilty to charges involving trading painkillers with women for sex. Dr. Barry Arnold, a 70-year-old Valley Stream dentist, allegedly prescribed Percocet, oxycodone and Xanax to women he knew were drug-addicted in exchange for sex. Nassau County prosecutors say they were not his patients, and the prescriptions were not for legitimate medical purposes. Arnold is charged with distribution of controlled substances and was released wearing an ankle monitor after posting a 200-thousand-dollar bond.