The difference between a pizza cutter and a regular knife

The difference between a pizza cutter and a regular knife is that the pizza cutter is thick. According to the query related to public information shows that the radius of the ordinary knife is small, and usually pizza are thicker, with other knives to cut pizza, the whole knife is sunk in the inside, simply can not wheel up, will get very dirty, pizza knife is different, the radius of 4.5 centimeters, with the use of course, it's a good idea.