A pulpotomy is when the inflamed pulp chamber, usually on a baby molar, is removed, the area is sterilized, and the chamber is sealed. It is sometimes called a baby tooth root canal, but it’s not really a root canal and it can be done is some cases in permanent teeth. It is a very common procedure in children and has a reasonably good prognosis of success. It’s also fairly easy to do in conjunction with associated procedures.
Pulpotomies have reasonably good prognosis. It may buy some time, but cannot save an already abscessed tooth. It is often surprising how a seemingly small area of decay can be deep enough to reach the pulp. This is often due to the varied anatomy of baby teeth and the rapid progression of decay.

Although a very reliable procedure, rarely, a tooth with a pulpotomy will have complications and need to be extracted. This is usually due to the remaining pulp tissue in the root canals that becomes infected,

Bottom line: a pulpotomy is a really good and reliable way to save a badly decayed baby tooth.