I've had invisalign for 13 months and recently had two extra attachments fitted on my front teeth at the bottom. Until now I had no problem removing the aligners - could pop them off easily with my nail or a teaspoon. The top ones still come off fine but the bottom ones are just impossible. My orthodontist showed me again how to do it today and gave me a plastic hook but still no good. The last 3 aligners have been cracking as I've pulled them out wrongly so now this 4th one is really tight and it's just snapped after half a day. I need help please!