The design looks fine. If anything the lips could wrap around the denture sphere more. Be sure you draw that whole egg representing the teeth and their relationship to the rest of the face. Second, you could develop the individual perspectives of the parts by giving a corner to the upper and lower lip.

Beautiful work Yevhen!

awesome practice! great job👍

good practice! In my opinion, you need to pay attention to proportions and to conveying the rhythm, not the contour of the figures. Keep practicing and over time you will be more satisfied with your result, I think the main thing now is to have fun practicing!