Hi Alberto,
Yes that will cause you duplicate content issues.
I'm working with a client at the moment that has a similar situation. I've advised them to have a YouTube description that gives an overview of the video content and contains some relevant keywords.
On your website you can embed your video on individual pages, add a brief summary and transcribe the video on the page. You could duplicate your YouTube description on this page, provided your transcription is lengthy enough so it's still unique content. I like to work on a ratio of 30% duplicate to 70% unique if it's necessary.
Transcribing 90 videos could be time consuming though, so check out these tools that can do it for you: http://www.vagueware.com/top-10-free-transcription-software-that-are-essential-to-your-va-or-transcription-business/
All the best,
Stel (@StelinSEO)