Oral hygiene refers to all procedures of keeping the teeth and mouth clean. Its practice is important in order to protect the health and prevent diseases like tooth decay, peridontal and gum disease.To maintain the oral hygiene we use basic and additional methods. The condition of children's oral hygiene in Croatia isn't very satisfying due to parent's unawareness of the importance of practising the tooth and mouth hygiene. Parents, who themselves should be practising the oral hygiene, carry the major responsibility in their children developing healthy habits of keeping the mouth and teeth clean. Furthermore, a healthy diet, which should be balanced and versatile, has an important role during teething and after the teeth arrive. While studying the curriculum for Science and Social Studies and the Eureka! 1 2 3 4 The Joy of Discovery textbook (original title: Eureka! Radost otkrića) for grades 1-4, I realized that it is necessary to bring the topic of oral hygiene to fourth graders due to the lack of its presence. I did just that through an integrated approach in teaching. The teaching and learning process encompassed 4 subjects, which I managed to carry out over the course of two school days. The general goals of said teaching and learning process were to raise awareness among students about the importance of oral hygiene, to teach them about the consequences of poor or non-existent oral hygiene and finally, to introduce them to ways which ensure a proper carrying out of oral hygiene. A fact sheet proved that the students gained new theoretical knowledge, but also, that some answers are connected with their oral health. The evaluation sheet showed that the teaching and learning process resulted in significant success.