INTRODUCTION:
Exclusive breastfeeding (EBF) has the greatest potential impact on infant mortality of any preventive intervention, its practice proves to be an approach that, in addition to preventing childhood illnesses and disorders, is also effective in preventing malocclusion in the primary dentition (1,2,3). The objective of this study is to evaluate exclusive breastfeeding among users of Basic Public Health Units in the Municipality of Vitória, Espírito Santo, and its possible associations with socioeconomic, maternal, and infant determinants, as well as primary health care, up to 30 days postpartum. The project was approved by the Research Ethics Committee of the Federal University of Espírito Santo and the Municipality of Vitória. It is currently in the data collection phase, carried out through the application of a questionnaire composed of closed-ended questions addressing socioeconomic, maternal, and infant variables related to primary health care and the practice of exclusive breastfeeding.

METHODS:
The sample size was calculated considering an estimated finite population of 1,000 postpartum women, a prevalence of 50%, a margin of error of 5%, and a confidence level of 95%, resulting in a sample of 329 participants. The data will be organized into frequency distribution tables; the association between exclusive breastfeeding (EBF) and the independent variables will be assessed using the Chi-square or Fisher's exact test, as applicable. The Odds Ratio (OR) will be used to measure the strength of the associations, with a 95% confidence interval (95% CI). Logistic or linear regression will also be applied to estimate the influence of the variables on the outcome, controlling for possible confounding factors. The significance level adopted will be 5%. Results and

CONCLUSIONS:
Identifying these determinants may help dentists formulate strategies to support breastfeeding within healthcare networks and strengthen comprehensive child health care.