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Our study aims to analyze the bond after the Er:YAG laser-radiation-prepared cavity was filled with a new kind of bulk-filled composite material. The laser radiation acted in a contact and non-contact mode. The setting for contact ablation was as follows: energy 250 mJ/pulse with a pulse repetition rate 15 Hz, giving an average power of 3.75 W. For non-contact ablation these values were 600 mJ/pulse, 6 Hz, and 3.6 W. Scanning ablation was provided in non-contact mode (1440 pulses/cavity) and the parameters were: energy 300 mJ/pulse, repetition rate 1 Hz, and mean power 0.3 W. Three types of laser cavities were filled with sonic activated composite resin.Four longitudinal sections were prepared after immersion in 5% methylene blue for 24 h. Microleakage was assessed quantitatively by the degree of dye penetration; the data were analyzed by the Fisher exact test with the level of significance set at p < 0.05.Contact and non-contact laser treatments prepared similar cavities (5167.31 versus 5356.31 µm). Defocusing of non-contact therapy has a direct influence on the presence of dye penetration microleakage (481.19 versus 611.94 µm). The non-contact scan is a more effective method for laser ablation (8508.05 µm). For that reason the dye penetration (microleakage) is higher (1458.65 µm). These results are statistically significant.

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The Demirjian methods to determine dental age are based on analysis of orthopantograms. The dental age estimation is based on establishing the tooth development stages. The purpose of this study was to assess the accuracy of estimation of dental age by Demirjian in the use of all of his four methods. 505 Czech healthy boys and girls aged 3 to 18 years were examined radiographically at the Department of Stomatology, Second Faculty of Medicine, Charles University in Prague. It was mentioned the factors of underlying diseases influence the accuracy of the dental age estimation. For statistical evaluation, descriptive statistics was used to compare deviations of the mean values of chronological and dental age in each age group. The resulting difference between dental age and chronological age is not significant in both genders only when using both Demirjian 7-teeth methods of 1973 and 1976. Therefore these may be most appropriately used for forensic age estimation. There are shown standard deviation differences in different countries. Demirjian's original 7-teeth method from 1973 and Demirjian's revised 4-teeth method from 1976 appear to be the best methods for calculating the dental age of healthy Czech children of both genders.

Key words: Dentistry -Hypodontia -Hyperodontia -Morphological anomaliesSize anomalies Abstract: 6,043 children, who were ordinary patients and children of Caucasian population, were examined clinically and radiographically. 430 children were aged 7-10 years. Dental anomalies were diagnosed in 14.1% (61 children) of those observed between 7-10 years. We aimed at numerical anomalies (78.6% of children with anomalies), morphological anomalies (19.6% of children with anomalies), size anomalies (3.2% of children with anomalies) and combinations of diagnoses (1.4% reflects the combinations of teeth 2 times calculated in combinations of diagnoses). Congenital numerical variations, i.e. hypodontia and hyperodontia, are among the most common deviations of the permanent dentition. Both conditions can occur as isolated traits or in association with other syndromes. Many studies indicate that hereditary factors are involved in the aetiology of anomalies. Gen MSX1 involves a primary position in mediating interactions between epithelium and mesenchyme in the development of teeth. Occurrence of dental anomalies is not very frequent; problems can arise with diagnosis of those affected teeth. It can be done using Orthopantomogram or Computed Tomography and 3D reconstruction. Some of the children with anomalies may have difficulties in treatment of affected teeth but in most cases the prognosis is good.