No, the presence of the tooth candy will not make any difference regarding dental hygiene. However, it is recommended not to use an electric toothbrush.
Dental jewellery will not cause a problem for the hygienist cleaning your teeth. You can and should still have your teeth cleaned by a dental visit twice a year. The area underneath the jewel is sealed like a filling and will not let in any bacteria. The dentist can easily polish on top and around the jewel with a soft point.