During hominid evolution, the dental system has constantly been liable to a reduction process, reflecting in numerous symptoms. The aim of this paper is to analyze the characteristics of some reduction symptoms: insufficient space, reduction of I2, hypodontia, reduction of upper and lower M1 and M2. We have analyzed 880 study models and orthopan X-ray films of orthodontic patients from Niš. The lack of space for maxillary incisors was found in quite a high percentage (about 43%). The reduction of I2 was present in only 5.5% of the patients, mainly in the I reduction phase (3.72%). The hypodontia of teeth is characteristic for 4.87% of our investigated patients. Of these patients, 55% did not have P2, about 23% lacked I2 in the maxilla and 14% lacked I1 in the mandibula. The absence of other teeth occurred sporadically. The reduction of upper M1 is less expressed as compared to M2. The total hypoconus reduction in M1 appeared in 1.98% and in M2 in 24% of the cases. In the molar group, lower M1 is the least reduced and it has 5 cusps in most of the patients (73.48%). In 95.52%, M2 has 4 cusps and numerous shape variations in both jaws.
