<p>I have found a video about Invisalign. I saw a 3D printer in the video but I did not understand its type. Can you help me? Do you share a brief piece of information about its type?</p>
<p>Below is the video on YouTube.</p>
<p><div class="youtube-embed"><div>
                <iframe width="640px" height="395px" src="https://www.youtube.com/embed/bKsGNrEKx9M?start=0"></iframe>
            </div></div></p>

If you look at the video at 37 seconds, it appears to be SLA or DLP.
Further reading:
https://www.solidprint3d.co.uk/wp-content/uploads/2019/04/SLA_vs_DLP.pdf