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.

The goal is to compare the strength of a fracture among titanium, fiber and zirconium posts. We have formed three group: titanium, fiber and zirconium,, and each group has 20 samples with 3 different diameters. The posts were tested using "Shimadzu Univerzal Testing Mashine" at the same distance, and the force was applied to all at the same place. The fracture strength was registered on a special software system. Between posts with the same diameter (1.2 mm) the greatest average fracture force has titanium posts 161.69 N (± 0.07), followed by fiber posts 45.38N (± 0, 01) and zirconium posts 34.81N (± 0.01). between the subgroups of the same  diameter (1.35mm), the greatest average fracture strength has the titanium posts 165.26N (± 0.01), followed by the fiber posts 71.57N (± 0.01) and zirconium posts 46.53N (± 0.004). between the subgroups of the same diameter (1.5 mm) the largest average fracture force has titanium posts 202.42N (± 0.01), followed by fiber posts 73.67N (± 0.004) and zirconium posts 67.15N (± 0.004). The diameter of the different types of posts gives different mechanical properties that affect differently the resistance of the fracture strength.