Susceptibility to Dental Caries and the Salivary Proline-Rich Proteins

Abstract

Early childhood caries affects 28% of children aged 2–6 in the US and is not decreasing. There is a well-recognized need to identify susceptible children at birth. Caries-free adults neutralize bacterial acids in dental biofilms better than adults with severe caries. Saliva contains acidic and basic proline-rich proteins (PRPs) which attach to oral streptococci. The PRPs are encoded within a small region of chromosome 12. An acidic PRP allele (Db) protects Caucasian children from caries but is more common in African Americans. Some basic PRP allelic phenotypes have a three-fold greater frequency in caries-free adults than in those with severe caries. Early childhood caries may associate with an absence of certain basic PRP alleles which bind oral streptococci, neutralize biofilm acids, and are in linkage disequilibrium with Db in Caucasians. The encoding of basic PRP alleles is updated and a new technology for genotyping them is described.

Human Salivary Acidic Proline-Rich Proteins (APRP-1/2) In Adult Patients With Dental Caries

“…The N-terminal domain ensures coupling of APRP-1/2 to hydroxyapatite and formation of the acquired enamel pellicle. In parallel the C-terminal domain of APRP-1/2 binds to oral bacteria, promoting bacterial colonization of dental surface, which may play a significant role in pathogenesis of caries [9,20].…”

“…In turn, it is well known that APRP-1/2 manifest high affinity for hydroxyapatite and are involved in the formation of dental-acquired pellicle [6][7][8]. It is also suggested that salivary APRPs may affect susceptibility to dental caries [9].…”

Salivary proteins as biomarkers in dental caries: In vivo study

“…Basic PRP's in whole saliva attaches to the major adhesion antigen on surface of S.Mutans, protecting the surface of tooth from caries.Thus greater the basic PRP's greater the adhesion and acid neutralization in biofilms. These proteins adhere strongly to the tooth surface and expose a previously cryptic binding site for bacteria within the non -binding C-terminal domain [3].…”

Salivary protein polymorphisms and risk of dental caries: a systematic review

“…38 Acidic PRPs are encoded by two genes, PRH1 and PRH2, with three different alleles at PRH1 (Db, Pa, and Pif). 39 When the allele Db was studied, 20 it was present in 72% of African Americans and in 26% of Caucasians. Curiously enough, large groups of African American children, regardless of the presence of Db, had significantly less caries experience than Caucasian subjects (p < 0.01).…”