Effect of Saliva Composition on Experimental Root Caries

Abstract

The aim of this study was to determine the effect of saliva composition on caries lesion development independently of the flow rate of unstimulated whole saliva (UWS) and other caries-related variables such as lesion progression time, oral hygiene level, and fluoride exposure. We hypothesized that this could be done by developing experimental root caries under carefully controlled conditions in situ in test subjects with UWS flow rates within a narrow window of normalcy. Fifteen female and 5 male subjects (66 ± 6 years) were selected for the study according to their UWS flow rates between 0.2 and 0.4 ml/min. All subjects developed experimental root caries lesions during a 62-day period in which UWS as well as stimulated whole saliva (SWS) were repeatedly collected and analysed for flow rate, pH, buffer capacity, inorganic, and organic composition. Caries lesion development was determined by quantitative microradiography. The mean UWS flow rate was 0.30 ± 0.05 ml/min. Significant negative correlations were obtained between UWS total phosphate concentration and mineral loss (ΔZ; r_s = –0.72, p < 0.001) and UWS total protein concentration and ΔZ (r_s = –0.70, p < 0.01). SWS and its constituents had only limited or no effect on ΔZ. Qualitative UWS protein analysis (SDS-PAGE) revealed that subjects with low ΔZ values had broader and more stained amylase bands than subjects with high ΔZ values. These findings were confirmed quantitatively by HPLC. We conclude that, within a group of subjects with normal UWS flow rates, the UWS composition was more important for caries lesion development than the SWS composition. Furthermore, high UWS concentrations of phosphate, protein, and amylase were caries-protective.

Dental caries and salivary status in children with type 1 diabetes mellitus, related to the metabolic control of the disease

“…Our results showed that increasing age and high dental plaque scores, as well as decreasing unstimulated flow rates were highly associated with increasing DMFS values, whereas no association was found with the level of HbA1c. These data confirm the existing knowledge about dental caries as a result of metabolic events in the dental plaque that is related to time (35) and might be enhanced by impaired functions of saliva (36, 37). Furthermore, higher counts of mutans streptococci and lactobacilli, as well as yeasts, were revealed in poorly controlled diabetics, indicating a possible ecological shift in the composition of oral microflora (38).…”

“…Decreased salivary flow, one of the most important determinants associated with a high caries prevalence in the present study population, could potentially explain the cariogenic changes in the oral environment of diabetics. It has previously been demonstrated that the effect of saliva on caries lesion development is very much influenced by the unstimulated flow rate and composition of saliva (36, 37). A reversible reduction of salivary secretion was found to be related to insulin deficiency and hyperglycemia in diabetics (4, 39).…”

The effect of parotid gland‐sparing intensity‐modulated radiotherapy on salivary composition, flow rate and xerostomia measures

“…Bardow et al. () showed in vivo that high unstimulated WMS concentrations of phosphate, TP and amylase were protective against caries. Finally, Garcia‐Godoy & Hicks () reported that Ca 2+ , phosphate and fluoride derived from saliva and sequestered in to the dental bio‐film are required for effective remineralization and maintenance of the enamel surface integrity.…”

Dental Caries Increments and Related Factors in Children with Type 1 Diabetes Mellitus

“…Some antimicrobial factors of saliva are considered to be caries protective [Amerongen et al, 2004;Bardow et al, 2005], and may have a beneficial effect on the ecology of dental plaque, but no single factor (except, perhaps, salivary flow rate) is able to affect oral health to a significant degree [Tenovuo et al, 1987;Gråhn et al, 1988;Rudney et al, 1993;Kirstilä et al, 1998]. …”