Saliva as a diagnostic tool for dental caries, periodontal disease and cancer: is there a need for more biomarkers?

ABSTRACT

Introduction: A biomarker is a biological indicator of normal or pathogenic processes. Identification of biomarkers is useful for the prevention, diagnosis and prognosis of diseases as well as for monitoring the progression of pathological disorders. Several types of molecules present in biological fluids can act as biomarkers such as DNA, coding and non-coding RNA, lipids, metabolites, proteins and even microbes. In this context, saliva emerges as a useful diagnostic tool for the detection of biomarkers involved with oral and systemic diseases, since it reflects the pathophysiological conditions of the organism and allows early, rapid, practical and noninvasive detection of biomarkers.

Areas covered: This review discusses the properties of saliva as a diagnostic tool and addresses the main identified biomarkers related to dental caries, periodontal disease, head and neck cancer and other types of cancer of considerable incidence among the world population.

Expert commentary: Despite extensive efforts which have been directed toward the identification of one or a combination of biomarkers with good predictive values for the early detection of dental caries, periodontal disease and cancer, these biomarkers still need validation before chairside point-of-care devices can be widely used in the clinic.

KEYWORDS:

• Biomarkers
• cancer
• dental caries
• diagnosis
• periodontal disease
• saliva

Article Highlights

• Identification of salivary biomarkers is useful for prevention, diagnosis and prognosis of diseases.

• Biomarkers exist in different forms, such as microbes, DNA, coding and non-coding RNA, lipids, metabolites and proteins.

• It is important to elucidate the complex interaction between different salivary biomarkers in caries rather than focusing on isolated proteins.

• Molecules present in saliva and gingival fluid have been considered as potential biomarkers for periodontal diseases.

• The noninvasive diagnosis of cancer by salivary biomarkers is critical for increasing patient survival.

Author contributions

ACO, TSC and MARB were all involved in the conception and design, analysis and interpretation of the data, drafting of the paper and revised it critically for intellectual content. SOMF, TTA, SMM, NRB and FNR were involved in the drafting of the paper and revised it critically for intellectual content. All authors give final approval for the version to be published and agree to be accountable for all aspects of the work.

Acknowledgments

The authors thank FAPESP for the concession of scholarship to TSC, SMM, TTA, FNR and NRB and CAPES for the concession of scholarship to SOMF.

Declaration of interest

The authors have no other relevant affiliations or financial involvement with any organization or entity with a financial interest in or financial conflict with the subject matter or materials discussed in the manuscript.

Reviewers disclosure

Peer reviewers on this manuscript have no relevant financial relationships or otherwise to disclose.

Additional information

Funding

The authors declare Coordenação de Aperfeiçoamento de Pessoal de Nível Superior Code 1 and Fundação de Amparo à Pesquisa do Estado de São Paulo 2019/08032-5, 2018/18147-1, 2018/18240-1, 2018/003 as sources of funding.