Technically, if you have charges dismissed, they are not part of your criminal record. However, if your employer is asking for everything you've ever been charged with, it would be honest to disclose it. If the charges do not come up on a background check, which they most likely wouldn't if they had been dismissed, you probably don't have to disclose if the employer is only asking for convictions. But remember, being honest about all charges is better, just in case the employer finds out later and disciplines you.
Sign up to receive a 3-part series of useful information and legal advice about DUIs.