Presence Of Salivary Pellicle Research Articles

Remineralisation of enamel white spot lesions pre-treated with chitosan in the presence of salivary pellicle

ObjectiveTo investigate the remineralisation of chitosan pre-treated enamel white spot lesions (WSLs) by bioglass in the presence of the pellicle layer. Methods50 artificial enamel white spot lesions were created by acidic gel. Two lesions were used to investigate the formation of the pellicle layer by treating with human whole saliva for 3 min. 48 lesions were assigned to 6 experimental groups (n = 8): (1) bioactive glass slurry, (2) bioactive glass containing polyacrylic acid (BG + PAA) slurry, (3) chitosan pre-treated WSLs with BG slurry (CS-BG), (4) chitosan pre-treated WSLs with BG + PAA slurry (CS-BG + PAA), (5) “standard” remineralisation solution (RS) and (6) de-ionised water (negative control, NC). Remineralisation was carried out using a pH-cycling model for 7 days. Before each treatment using remineralising agents, 3-min pellicle was formed on lesions’ surfaces. Mineral content changes, surface and subsurface microhardness and ultrastructure were evaluated by Raman intensity mapping, Knoop microhardness and scanning electron microscopy, respectively. Data were statistically analysed using one-way ANOVA with Tukey’s test (p < 0.05 is considered as significant). ResultsDespite the heterogeneously formed pellicle layer, all groups showed an increase in surface mineral content after pH-cycling. Chitosan pre-treatment enhanced the subsurface remineralisation of WSLs using bioglass as both pre-treated groups showed greater surface and subsurface microhardness compared to NC. CS-BG exhibited denser subsurface structure than BG, while in CS-BG + PAA the crystals were bigger in size but resemble more enamel-like compared to BG + PAA as shown in SEM observations. Remineralisation of RS was limited to the surface as no significant subsurface changes of mechanical properties and structure were found. ConclusionsChitosan pre-treatment can enhance WSL remineralisation with bioglass biomaterials when a short-term salivary pellicle is present. A further investigation using a long-term pH-cycling model with mature pellicle is suggested with regards to clinical application. Clinical significanceChitosan pre-treatment has the potential in clinical application to remineralise subsurface lesions to achieve lesion consolidation.

Protective Effect of Phosphates and Fluoride on the Dissolution of Hydroxyapatite and Their Interactions with Saliva

This study aimed to investigate the effect of phosphates and fluoride, alone or in combination, and the influence of salivary pellicle on hydroxyapatite (HA) dissolution. The baseline dissolution rate of HA discs was measured using a pH-stat system (0.3% citric acid, pH 3.2). In the first series of experiments, HA discs (n = 8/group) were treated with: a placebo solution (PLA, deionised water); sodium trimetaphosphate (TMP), sodium tripolyphosphate (TRI) and sodium pyrophosphate (PYRO) at 1 or 8%; 500 ppm F; 1,100 ppm F; 1,100 ppm F/1% TMP; 1,100 ppm F/8% TMP; 1,100 ppm F/1% TRI; 1,100 ppm F/8% TRI. In the second phase, HA discs were immersed in pooled human saliva (37°C/2 h) and treated with PLA, 1,100 ppm F/1% TMP, 1,100 ppm F/8% TMP, 1,100 ppm F/1% TRI, and 1,100 ppm F/8% TRI. After treatments, final dissolution rates were measured from 3 consecutive 30-min assays. Statistical analyses were performed using 2-way ANOVA followed by the Fisher test (α = 0.05). The type and concentration of phosphate tested significantly influenced HA dissolution; 8% TRI showed the highest reduction (36.9%) among all treatment solutions. Fluoride alone (1,100 ppm F) significantly reduced HA dissolution by 20.7%. When fluoride and phosphates were associated, 1,100 ppm F/1% TMP, 1,100 ppm F/8% TMP, and 1,100 ppm F/8% TRI showed the highest percentage reductions of dissolution (40.3-46.1%). Salivary pellicle led to a greater and more sustained protective effect of the treatment solutions compared to their counterparts without salivary coating. It was concluded that the association of phosphate and fluoride enhanced their protective effect against HA dissolution when compared with these compounds alone, especially in the presence of salivary pellicle.

Adhesion of Streptococcus mutans to Different Types of Brackets

To examine the difference in the adhesion of Streptococcus mutans to three different types of orthodontic brackets and the effect of the presence of an early salivary pellicle and Streptococcus sanguis on adhesion. Three adhesion experiments were performed using stainless steel, ceramic, and plastic orthodontic brackets. In the first experiment a clinical strain of S mutans adhered to the three different types of brackets (n = 6 for each). For the second, the brackets were treated with saliva before adhesion of S mutans (n = 6 per type of bracket). Finally, the third experiment concerned saliva coated brackets (n = 6 per type of bracket), but before S mutans, S sanguis bacteria were allowed to adhere. The bacteria were always allowed to adhere for 90 minutes in all the experiments. Adhesion was quantitated by a microbial culture technique by treating the brackets with adhering bacteria with trypsin and enumerating the total viable counts of bacteria recovered after cultivation. There were consistently no differences in the adherence to stainless steel, ceramic, or plastic brackets. The presence of an early salivary pellicle and S sanguis reduced the number of adhering S mutans to all three types of brackets. Adhesion of bacteria to orthodontic brackets depends on several factors. The presence of a salivary pellicle and other bacterial species seem to have a significant effect on the adhesion of S mutans, reducing their numbers and further limiting any differences between types of brackets.