"I have many areas of interest and, at this point, am not committed to any particular subspecialty down the road. I look forward to learning well-rounded dentistry skills at Western University and finding my niche once I get into your clinical rotations."

First and foremost, there is no right or wrong answer to this question. Be honest with your interviewing team. If you have a specific subspecialty you know you want to pursue, talk about that path and any additional fellowship you'll likely look to pursue. If you are unsure at this time and want to let the coming years be your guide, that is okay too. Just reiterate that to your interviewers. With a question like this, it's always a good idea to research the subspecialty areas like endodontics, orthodontics and dentofacial, prosthodontics, pediatrics, periodontics, and oral and maxillofacial surgery so you can come to your interviewer prepared to discuss them.