Even from the distant past the aesthetic perception in an individual was diminished by the presence of gap between the central incisors. This condition is found under the term "dents du bonheur" or "lucky teeth" and is encountered even among world famous figures including Brigitte Bardot, Eliah Wood, Madonna, Zac Efron, Amy Winehouse and Elton John. The teeth gaps are still considered main reasons for dissatisfaction of the dental patients and reasons for the requirement of aesthetic treatment. The purpose of this study is to exhibit the influence of the etiological factors in the occurrence of diastema mediana classified according to the dominance of their occurrence expressed in percentage values. Materials of this investigation were 100 patients with diastema mediana from the following factors: inheritance, disproportion in the dental arches, inborn or acquired missing teeth, harmful oral habits, high insertion of the labial frenulum as well as mesiodens. After the diagnosis and evaluation of the etiological factor for diastema mediana was performed, a decision regarding the course of treatment was made in direction of the removal of the etiological factor at an early age and orthodontic treatment. The end of the orthodontic treatment in a group of the patients was the beginning of prosthodontic reconstruction. From our clinical investigation we came to the realization that in 49 patients (49%) the hereditary influence was a dominant factor, next followed disproportions and discrepancies in the dental arch in 14 (14%), inborn or acquired missing teeth in 11 patients (11%), harmful oral habits in 10 (10%), high frenulum insertion in 4 (4%), and pathological objects between central incisors, mesiodens, iatrogenic factors and periodontal disease, in 3 of the clinical cases (3%) each. We concluded that the occurrence of diastema mediana is multi-causal. The dominant place is occupied by the hereditary factors. With regard to the mutual relationship between the multitudes of factors in the occurrence of diastema mediana, the diagnosis should be made conciliary and the clinical treatment should be interdisciplinary including a prosthodontist, orthodontist and oral surgeon.