Can Saliva be the New Bio-fluid to Monitor Children's Oral Health?

Salivary diagnosis is an emerging field that has progressed through several important developments, including salivary proteome and the development of compact point-of-care devices for rapid analysis. Indeed, an increasing number of salivary markers have been identified; and some have been associated with cancer, cardiovascular diseases, autoimmune diseases, viral and bacterial diseases, and human immunodeficiency. Saliva is frequently studied due to the easy, non-invasive, and rapidly obtained collection, without the need for specialized equipment. Moreover, the prodigious fluid source of saliva provides many, if not most, of the molecules found in the systemic circulation, rendering it a potentially valuable bio-fluid for diagnoses.

Several types of inflammatory biomarkers associated with oral diseases, as well as systemic diseases, have been detected in saliva. Cytokines are among the most investigated biomarkers in this context. Due to their involvement in inflammatory, infectious and immunological diseases, cytokines may serve as markers of local oral pathologies such as periodontal disease and carries. Indeed, in adults, evidence shows that such disease can be detected through saliva biomarkers such as interleukins (IL)-1b, -6, -8 and -10), tumor necrosis factor- α (TNF- α) and matrix metalloproteinases (MMP)-8 and -9 in adults. Additionally, as some etiologies of oral pathology as gingivitis include bacterial infection such as Streptococcus, Fusobacterium, Actinomyces, Veillonella, Treponema, Capnocytophaga and Eikenella, saliva may also be used to measure bacterial load.

Dental caries is one of the most common childhood diseases worldwide, and is associated with polymicrobial colonization on tooth surfaces. Both acidogenic and aciduric bacteria, such as the Mutans group of Streptococci and Lactobacilli, are primary etiological agents of dental caries. Lactobacilli and S. Mutans are mostly found together in saliva . The diversity of microbes in saliva has been shown to increase in the caries active status. In children with cavitated carious lesions, altered concentrations of the cytokines IL-6 and IL-8 were reported.

The objective of this study was to characterize the inflammatory and microbiological profile of the saliva of healthy children, and to associate those levels with clinical diagnosis of caries and gingival disease.

Materials and methods Study population The study population comprised 100 participants, born during 2008-2016 (aged 4-12 years at the time of the study).