<prompt> Kim et al classification system deals with:Apical constrictionApical foramenIsthmusNo. of canals  <response>: According to Kim et al Classification; there are 5 typesType I incomplete isthmus between 2 canals.Type II well defined, complete isthmus between 2 canals.Type III very short but complete isthmus between 2 canals.Type IV 3 or more canals with the complete or incomplete isthmus.Type V 3 or more canals without any visible connection. 