Why "Philips Sonicare Toothbrush", specifically?
Philips is only one brand of toothbrush, and toothbrushes are only one kind of electronic consumer device (like CFLs, televisions, computers and any number of things), all of which share the same basic components in manufacturing.
If you want to know about the contents of electronics and electronic waste in general, there must be a ton of material out there which is easily researched.
What is it you want to know, exactly, that you can't find by a normal literature search?