If you have no intentions of specializing, then you will be fine. I am shooting for an OMS residency so was studying hard to have a high class rank and also be prepared for the NBME CBSE. I literally had NO time for anything other than school work and studying for the CBSE for the last year. Now that I am done with the CBSE (still waiting for scores to come out) I have so much more free time.
Most people need to improve on their time management skills after starting dental school. You get the hang of it after the first couple of quarters.