The bacterial microorganisms of the oral cavity are frequently associated with the onset of caries and periodontal disease. These diseases are produced as a consequence of an imbalance between the resident microbiota of the oral cavity and the appearance of emerging bacterial pathogens. Likewise, the development of these types of disorder depends on factors closely associated with the individual. Of special importance among these factors is the role of secretory immunoglobulin A (SIgA), which constitutes the principal specific immune mechanism of the saliva and plays a fundamental role in the homeostasis of the oral microbiota. SIgA reacts against a variety of pathogenic bacterial agents found in saliva. These antibodies have the ability to control the bacterial flora, as they reduce the adherence of the bacteria to the oral mucosa and to the teeth. Protection against the bacterial etiological agents associated with the onset of caries and periodontal disease may be stimulated by the induction of SIgA synthesis by stimulation of the immune system of the oral mucosa (58).