Kibble does not really clean teeth that much. In essence, that is like telling a human eating hard pretzels every day will keep your teeth clean... which they won't. That's been a myth for a while. It MAY help a TINY bit with scraping off some tarter, but it's not a replacement for brushing teeth and other oral care and doesn't really help teeth that much.
I totally get what you're saying about the tiny kibble though. I have a 15lb boy and when I fed the tinier kibbles, I always felt like he basically swallowed them! Orijen and Acana have larger kibbles for sure. Some think they are TOO big for their little ones, but my friends 4 and 6lb yorkies eat them just fine. But Orijen and Acana are some of the bigger kibbles out there and IMO, you currently can't get much better than Champion Pet Foods in general! Wellness CORE and Wellness Super5Mix Adult also have fairly 'large' kibbles.
Here's an old thread:
http://www.yorkietalk.com/forums/yor...na+kibble+size