There's no standard meaning for "ms DDS". It's likely an abbreviation specific to a certain context. To understand what it means, you'd need to provide more information about where you encountered this abbreviation. For example:
* What was the subject or topic being discussed? (e.g., medical, engineering, computer science)
* What was the surrounding text? The words before and after "ms DDS" might provide clues.
Without more context, it's impossible to say for sure.