For an aesthetically pleasing smile it is necessary to know the basic criteria of aesthetics. This thesis deals with the basic rules or criteria in cosmetic dental medicine and presents it on a clinical case of a 49-year-old female patient who has requested assistance due to the compromised aesthetics in the frontal area of the upper jaw, pain in the temporomandibular joint and clenching of teeth during the day and at night. The treatment plan was for the patient's bite to be lifted because of the deep bite, which was the result of the teeth clenching, making a temporary aesthetic restoration from composite materials and making a biting relaxation splint. Finally the above stated treatment achieved following: a reduction of pain in the temporomandibular joint, better aesthetics of the lower third of the face and smile detection, prevention of tooth wear, reducing clenching teeth and patient satisfaction. The aim of this thesis is to present on the clinical case of the patient in question, which aesthetic rules have to be taken into consideration when making front teeth restorations. It is also to show what progress has been achieved and what mistakes have been made. After the therapy, it was observed that it is most important to consider the smiling line, incisal length, the symmetry of the middle teeth line and the face line, proper layering of the composite materials, the use of transparent colours, a proper polishing of the final preparation and the use of the silicone key. There is a saying "Beauty is in the eye of the beholder," which implies that there is no universal criteria of beauty. That is why in aesthetic dentistry it is important to cooperate with the patient, because this is the only way to meet his or her expectations.