This was a quick drawing I did just under 2 hours. I basically used cross-hatching technique for shading. The reference picture used for this drawing is:

Shyam with all his toothless grin taken during new year celebration when he was 9 months old. Thanks Devina for taking this wonderful picture!

P.S: I need to work on my shading skill. The shading for the smile ridge seems to be a tad darker.

More info on cross-hatching:

Portrait # 3