A contemporary view of salivary research

The past 50 years of salivary research has been marked by a series of changing perceptions as new techniques and technologies have illuminated the complexities of the secretory mechanism, salivary composition, and function. The modern era began with the innovations of electrophoresis, chromatography, histochemistry, immunochemistry, electron microscopy, and microphysiology. The idea of saliva as primarily a digestive fluid composed of salts, amylase, and mucin was rapidly broadened to encompass a wide spectrum of protective proteins with the dual responsibility of protecting both hard and soft tissues. Characterization of the secretory IgA and nonimmunological antibacterial systems and the proteins responsible for the regulation of calcium and phosphate levels dominated the research in the 1960s and 1970s. An appreciation of the nature, formation, and role of the salivary pellicle and the interplay between bacterial adherence and agglutination provided a clinical thrust. Morphologists and physiologists redefined the secretory process on a molecular level. The 1980s saw the union of structure and function, both in terms of synthesis and release of the secretory products and their specific roles in the oral cavity in health and disease. The excitement of the 1990s is in the genetic control of processes and products, elucidating the mechanisms, and using the information to improve on nature: an era of great expectations and hubris. This article is essentially a personal guided tour through the past 50 years of salivary research.