Aware of the importance of the prevention and control of infections in dental practice, it has been considered that the realization of this research is of great importance due to the need to emphasize the necessary precautions to avoid the transmission of infectious diseases. 1 The investigation was carried out in the health units of San Miguelito, Ciudad Delgado, Zacamil and Díaz del Pina) in Santa Tecla, in order to verify whether the application of bio-security measures was carried out by the dental personnel who work in these units, since they are in contact with materials, instruments and patients that may be a possible risk of cross contamination. This research work is divided into four phases Phase I In the 9th that the elements of the diagnosis are determined, the importance of the adequate application of prevention measures is justified to know if the study population put them into practice, the general objective to be achieved at the end of the investigation and the specific objectives to be achieved according to each of the preventive measures. In addition, it is explained what were the limitations that were presented for the development of the work, at the end of this phase a series of basic dental terms were presented to help a better understanding of the content of the research. Phase II is the Reference Framework that consists of two sections in the first, the antecedents of the problem under study are presented, which begins with a historical review in which the beginning of the application of prevention measures is announced. and how they have been evolving thanks to advances in science and discoveries related to the subject. The second section includes a bibliographic discussion in which the different approaches of specialist authors of books and protocols on medical and dental asepsis are exposed, as well as the diverse opinions of people familiar with the subject who were interviewed. Phase II is the Reference Framework that consists of two sections in the first, the antecedents of the problem under study are presented, which begins with a historical review in which the beginning of the application of prevention measures is announced. and how they have been evolving thanks to advances in science and discoveries related to the subject. The second section includes a bibliographic discussion in which the different approaches of specialist authors of books and protocols on medical and dental asepsis are exposed, as well as the diverse opinions of people familiar with the subject who were interviewed. Phase III corresponds to the Methodology, in which it is defined that the research is of a diagnostic type, whose population under study is made up of dentists, operators and assistants, stationed in the dental clinics of the aforementioned health units. It also raises the reason why the interview guide and the survey were considered the appropriate techniques for collecting information, it also explains the way in which the instruments were applied and the problems encountered at the time of doing so. likewise the way in which the process of emptying the information was carried out. Finally, the methodology to be used to analyze the data was specified. ix Phase IV called diagnosis results, includes the presentation of statistical tables with their respective analyzes in which the results obtained through the instruments are interpreted, a general analysis of the problem under study is also proposed based on the results of the diagnosis , the own experience of the researchers and the opinion of the various authors consulted. Likewise, this section establishes the specific and general conclusions that were reached after the analysis of the problem. In addition, pertinent recommendations are made both to the personnel who work in the dental clinics of the Health units under study and to the Ministry of Public Health and Social Assistance.