Influence of salivary conditioning and sucrose concentration on biofilm-mediated enamel demineralization

Abstract

Influence of salivary conditioning and sucrose concentration on biofilmmediated enamel demineralizationThe acquired pellicle formation is the first step in dental biofilm formation. It distinguishes dental biofilms from other biofilm types. Objective: To explore the influence of salivary pellicle formation before biofilm formation on enamel demineralization. Methodology: Saliva collection was approved by Indiana University IRB. Three donors provided wax-stimulated saliva as the microcosm bacterial inoculum source. Acquired pellicle was formed on bovine enamel samples. Two groups (0.5% and 1% sucrose-supplemented growth media) with three subgroups (surface conditioning using filtered/ pasteurized saliva; filtered saliva; and deionized water (DIW)) were included (n=9/subgroup). Biofilm was then allowed to grow for 48 h using Brain Heart Infusion media supplemented with 5 g/l yeast extract, 1 mM CaCl 2 .2H 2 O, 5% vitamin K and hemin (v/v), and sucrose. Enamel samples were analyzed for Vickers surface microhardness change (VHN change ), and transverse microradiography measuring lesion depth (L) and mineral loss (∆Z). Data were analyzed using two-way ANOVA. Results: The twoway interaction of sucrose concentration × surface conditioning was not significant for VHN change (p=0.872), ∆Z (p=0.662) or L (p=0.436). Surface conditioning affected VHN change (p=0.0079), while sucrose concentration impacted ∆Z (p<0.0001) and L (p<0.0001). Surface conditioning with filtered/pasteurized saliva resulted in the lowest VHN change values for both sucrose concentrations. The differences between filtered/pasteurized subgroups and the two other surface conditionings were significant (filtered saliva p=0.006; DIW p=0.0075). Growing the biofilm in 1% sucrose resulted in lesions with higher ∆Z and L values when compared with 0.5% sucrose. The differences in ∆Z and L between sucrose concentration subgroups was significant, regardless of surface conditioning (both p<0.0001). Conclusion: Within the study limitations, surface conditioning using human saliva does not influence biofilm-mediated enamel caries lesion formation as measured by transverse microradiography, while differences were observed using surface microhardness, indicating a complex interaction between pellicle proteins and biofilm-mediated demineralization of the enamel surface.

Effectiveness of in vitro primary coronal caries prevention with silver diamine fluoride - Chemical vs biofilm models

“…Silver ions are assumed to be primarily responsible for the antimicrobial action of SDF by inhibiting the growth of S. mutans, a primary pathogen in dental caries. Thus S. mutans is less able to form a biofilm on teeth treated with SDF ex vivo [18][19][20]. While excess silver ions are removed by KI in both demineralization models, the impact in the chemical model is negligible as silver ions do not appear to interact in de-and remineralization processes [23].…”

“…Specimens were demineralized by aerobic incubation in a clinically relevant overnight culture of cariogenic bacteria including S. mutans. An overnight culture of multi-species bacterial mix, which was previously collected from human saliva under IRB approval #1406440799 based on Ayoub et al 2019 [19], was mixed with an overnight culture of S. mutans strain UA159 (ATCC 700610) in a 10:1 volume ratio. Each specimen was incubated in a six-well tissue culture plate containing the bacterial inoculum for 72 h, aerobically to create caries lesions.…”

Oral Biofilm and Its Impact on Oral Health, Psychological and Social Interaction

“…These stages of the cycle are determined by physical, biological and environmental factors. Generally, the formation of dental biofilm (or dental plaque) consists of several steps, which start with the formation of the acquired enamel pellicle, followed by the initial adhesion of planktonic bacteria to the pellicle layer by binding sites, subsequent maturation of the bacterial biofilm and, finally, the dispersion of biofilm with detachment of cells/clusters of cells [29] (Figure 1).…”

“…The consistent presence of acid in the environment disrupts the mineral equilibrium of the exposed dental structures (i.e. enamel and/or dentin), and, therefore, leads to carious lesions [29]. Acidic environment also imposes environmental stress on the microbial community causing acid-sensitive species to perish and aciduric microbiota to flourish [35].…”

“…Therefore, the composition of the acquired pellicle can modify the mineral homeostasis of the tooth surfaces and the attachment of bacteria for the development of the biofilm [31]. The formation of acquired pellicle is the first step in dental biofilm formation and it distinguishes dental biofilms from other biofilm types [29] (Figure 1). The salivary pellicle that coats the tooth surfaces is mediating the attachment of oral bacteria on to these surfaces [32].…”