Introduction: In dental medicine, that is, in oral medicine as one of its subspecialties, as in any other scientific discipline, there are some specific terms that should be taught and learnt. Moreover, these concepts and terms should be expressed in a foreign language. Since the English language has become the most widespread language of communication in the world, there is a need to express all these concepts ideas and insights in English and vice versa: terms expressed in mother language, in our case Croatian, should be translated into English. Teaching, learning and translating special words and collocations, as the examples of lexical units, are probably major problem areas in this respect. Collocations appear when a sequence of words or terms co-occur more often than would be expected by chance, thus changing the meanings of previously isolated words. In this paper collocations in oral medicine are the focus of interest. The aim was to investigate into meanings of particular words that form a collocation thus showing how the prototypal meaning expressed in one language is communicated into another, and how the collocations differ in the two languages analyzed. Material and methods: In this study examples of collocations used in oral medicine are analysed by employing the method of contrastive analysis. Results: The illustrative examples point to certain differences in the two analyzed languages to which attention must be payed when translating in order to preserve the meaning thus avoiding a misrepresentation of collocation. The results also show that there is no symmetry between the structures of languages. Conclusion: Identifying collocations in technical language is essential for their understanding and accurate translation into another language.