¹CliniC OF dentistrY-dePartMent OF OrthOdOntiCs,
² uniVersitY OF nis-FaCultY OF MediCine, nis, serbia

Aim: To find the existence of variability in the number of primary cusps of the lower first and second molars M1 and M2.
Materials and methods The study was conducted on the models of 400 orthodontic patients (164 males and 236 females),.
Results It was found that the lower molars M1 in the group is least subject to reduction so that the majority of patients within gender groups (75.61% boys and 66.95% girls), have the presence of all five basic cusps type M1-5. Type M1-4, where there is complete absence of hypoconulid has 21.35% 32.63% boys and girls. The presence of the sixth cusp is found at 3.05% and 0.42% of boys of girls. Type M2-4 dominated in both sexes (86.59% boys and 91.1% girls), while type M2-5 found in much smaller percentage (13.41% boys and 8.9% girls).
Conclusion The subjects of our sample are characterized by a high percentage of the presence of M1 with five cusps (70.5%) and M2 with 4 cusps (89.25%). It has been established the total absence of only distovestibular cusp-hypoconulid.

Key words: cusps number, variation, fists molar, second molar