The study was done on 304 plaster models of orthodontic patients from Clinic of stomatology in Nis. The number of cusps and mesio-distal diameter of m2 and M1 was analyzed, in maxilla and mandible according to sex. The same number of cusps at both sexes was found in maxilla in 96,40% and 92,76%,in mandible the difference of cusp number was greater(30,92% and 26,97%). At major number of patients mesio-distal diameter difference was up to 2mm:in maxilla about 88% in mandible about 68%.The same diameters of m2 and M1 in maxilla was measured in 8% of patients, in mandible more patients had same diameter, about 30%. In mandible m2 is more similar to M1 in mesio-distal diameter. In maxilla m2 is more similar to M1 in the number of cusps. .
