Cement molding
A bone cement filling operation will increase the head circumference by several centimeters, which varies from person to person.

Generally speaking, because the scalp skin is stretched, filling with bone cement can increase the forehead by 0.5 cm. The top of the head can increase by about 1 cm. The back of the head can be increased by about 2 cm. The coverage width of surgical filling is about 10- 12 cm, and the parts with muscles cannot be filled. Like temples and brow bones, they cannot be filled.

You can consult Korean sculpture for details.