As long as you haven't overclocked your hardware there shouldn't be any reason why your CPU should suffer from 100% use. After all, if you can't use your rig for all it can do, you've been ripped off. I guess laptops have heat dissipation problems moreso than normal computers, but even so it shouldn't overheat just because you're using it according to its factory specifications.
100% CPU usage can be troublesome for other reasons, though, especially multitasking related ones.