Conservative dentistry is a branch of dentistry which studies congenital and acquired damages of the hard tooth substance. When it comes to those congenital, the most significant are anomalies of the hard tooth substance (aplasia, hypoplasia, dysplasia), while in case of acquired damages, the most common are tooth cavities, but other, the so-called non-carious lesions are also studied. Apart from disease (damage) aetiology and pathogenesis, conservative dentistry also studies dental materials used for filling cavities after preparation. The procedure of cavity preparation and placement of dental fillings is colloquially called tooth repair and sealing. Cavity preparation and placement of fillings is one of the most widespread medical interventions. The reason is widespread presence of dental cavities. At our office, we keep up with global standards and top composite materials 3M and Gradia. Regular maintenance of oral and tooth hygiene and preventive visits to the dentist’s office reduce the possibility of the appearance of cavities.