Demineralization Of Tooth Structure Research Articles

The Evolving Microbiome of Dental Caries.

Dental caries is a significant oral and public health problem worldwide, especially in low-income populations. The risk of dental caries increases with frequent intake of dietary carbohydrates, including sugars, leading to increased acidity and disruption of the symbiotic diverse and complex microbial community of health. Excess acid production leads to a dysbiotic shift in the bacterial biofilm composition, demineralization of tooth structure, and cavities. Highly acidic and acid-tolerant species associated with caries include Streptococcus mutans, Lactobacillus, Actinomyces, Bifidobacterium, and Scardovia species. The differences in microbiotas depend on tooth site, extent of carious lesions, and rate of disease progression. Metagenomics and metatranscriptomics not only reveal the structure and genetic potential of the caries-associated microbiome, but, more importantly, capture the genetic makeup of the metabolically active microbiome in lesion sites. Due to its multifactorial nature, caries has been difficult to prevent. The use of topical fluoride has had a significant impact on reducing caries in clinical settings, but the approach is costly; the results are less sustainable for high-caries-risk individuals, especially children. Developing treatment regimens that specifically target S. mutans and other acidogenic bacteria, such as using nanoparticles, show promise in altering the cariogenic microbiome, thereby combatting the disease.

Silver diamine fluoride versus sodium fluoride for arresting dentine caries in children: a systematic review and meta-analysis

Dental caries can compromise quality of life and is associated with demineralization of tooth structure by organic acids produced by microorganisms. This study systematically reviewed the dentine caries arrest capabilities of silver diamine fluoride (SDF) and sodium fluoride (NaF). A comprehensive search strategy was developed to identify the relevant publications in electronic databases and hand searched journals and reviews (to March 2018). By applying strict inclusion and exclusion criteria, only six papers (two randomized controlled trials, two follow-up articles and two secondary statistical analysis studies) were considered for full text qualitative and quantitative assessment. The included studies were critically appraised and statistically evaluated. Only four articles were considered for meta-analysis, as the other two were secondary analyses of included studies. When comparing the caries arrest lesions of SDF and NaF, SDF was found to be statistically more effective in dentine caries arrest of primary teeth during the 18 and 30 month clinical examinations. The weighted total effect size of the differences between SDF and NaF regarding arrested caries surfaces was calculated and showed nearly double the effectiveness of SDF to NaF at 30 months. Therefore, SDF is a more effective caries management reagent than NaF. Further clinical research is needed to consolidate the findings of this systematic review.

Comparison of the Effect of Three Types of Iron Drops on Surface Roughness of Deciduous Teeth in a Simulated Cariogenic Environment

Objective: Iron deficiency anemia is among the most common types of childhood anemia. According to the World Health Organization, approximately 5 billion people were suffering from iron deficiency anemia worldwide in 2001. Aside from causing anemia, iron deficiency can negatively affect the physical and mental development of children and adolescents. Several studies have discussed the consequences of inadequate iron intake among which we may name changes in deciduous teeth. Considering the importance of iron supplementation, the present in-vitro study aimed at assessing the surface roughness of deciduous teeth following exposure to three different iron drops.Methods: This in-vitro experimental study was conducted on 90 sound anterior deciduous teeth that were divided into 6 groups. After surface preparation, the teeth were placed in cariogenic environment. Different ferrous sulfate compounds were added to 4 media and the remaining two groups were considered as positive and negative controls. Fourteen days later, the specimens were removed from the media, sectioned labiolingually, polished and enamel and dentin microhardness were evaluated. The mean microhardness value for the 15 specimens in each group was recorded. ANOVA was applied for comparison of data and LSD test was used for multiple comparisons.Results: No statistically significant differences were found in enamel microhardness of the 6 understudy groups. The mean microhardness of dentin was significantly different in the three understudy depths. Dentin microhardness immediately below the DEJ, at 250 Mm distance from the DEJ and at 450 Mm distance from the DEJ was (kgf/m2) 68.72 (10.00), 67.75 (8.75) and 68.75 (11.86) in group 1, 69.22(12.46), 73.06 (9.36) and 69.29 (8.01) in group 2, 68.533 (12.27), 64.63 (10.64) and 69.64 (10.15) ingroup 3, 83.033 (11.22), 71.68 (16.01) and 70.88 (17.60) in group 4, 60.080 (9.83), 63.52 (14.46) and65.49 (11.20) in group 5 and 91.91 (43.76), 88.62 (20.47) and 85.04 (26.56) in group 6 (p=0.001 for all three), respectively. Pair-wise comparison of groups revealed that the mentioned difference is due to the statistically significant differences between group 6 and other groups and the remaining groups were not significantly different.Conclusion: This study showed that iron supplementation had no effect on demineralization of tooth structure.

An estimation of fluoride release from various dental restorative materials at different pH: In vitro study

In the mid of 1980s, the cariostatic effect of fluoride ions on enamel caries had been demonstrated in many studies. The use of fluoride releasing dental restorative materials has seen increasing from many years for the specific purpose of leaching of fluoride into the surrounding tissues to inhibit secondary dental caries as well as prevention of caries in the newly erupted tooth. In the dental caries, acidic environment causes the demineralization of tooth structure and also affect the restorative margins of dental restoration. various restorative materials show different behavior in different pH conditions of oral cavity. Thus, the aim of this study was to evaluate the fluoride release of the various restorative materials at different pH. In this in vitro study, 30 samples of each dental restorative material were prepared and grouped into five with six samples in each group as per the pH of the solution 4.3, 4.6, 5.0, 5.5, and 6.2. All the samples were subjected to alternate cycling of the demineralizing solution (6 h) and remineralizing solution (18 h) for 15 days. the fluoride release was measured by using fluoride ion specific electrode and digital ion analyzer. The result showed that the fluoride release rate was significantly higher in first day and reduced after third day to nearly constant level. At pH 4.3, the fluoride release was highest and lowest at pH 6.2. the Amalgomer CR showed the highest fluoride release among all the experimental dental restorative materials.

The role of salivary peptides in dental caries.

Dental caries is a complex disease, characterized by demineralization of tooth structure. With a protective role, several salivary phosphopeptides appear to be involved in remineralization processes, delaying the loss of tooth structure. In this work we have correlated peptide saliva composition with dental caries susceptibility through the analysis of saliva and hydroxyapatite-adsorbed salivary peptides samples. Saliva samples were obtained from two groups, a caries-free and a cariessusceptible group, and were analysed using HPLC-MS and a sequential extraction with 6 m of guanidine followed by tri fluoroacetate. Data analysis has allowed us to verify a strong correlation between large amounts phosphopeptides (PRP1/3, histatin 1 and statherin), and the absence of dental caries, which reinforces the importance of these peptides in the maintenance of tooth integrity. In addition, in the caries-susceptible group a high number of peptide fragments was observed, suggesting a high proteolytic activity.

Acid-Assisted Consolidation of Silver Alloys for Direct Fillings.

Silver-rich metal powders cold-welded by consolidation have been investigated as possible direct dental filling material. The surface of the silver powder must undergo an acid treatment to remove existing contaminants and prevent formation of new surface contaminants during consolidation. This study was designed to investigate the effect of the acid treatment on the strength of the consolidated alloy, its reactivity with the surrounding tooth structure, and its reactions with certain cavity liners.This study investigated the effects of pH and concentration of fluoboric acid on the flexural strength of silver powder consolidated into rectangular beams in a partial 4 × 4 design. The study also assessed, by visible and scanning electron microscopy, what effect the acid-treated powders had on dentin that had been pre-coated with different cavity liners. Mean flexural strengths for beams consolidated using dental hand instruments were in the range (77.0 ± 9.28) MPa to (166.1 ± 17.6) MPa, where the quoted uncertainties are standard uncertainties (i.e., one standard deviation estimates). ANOVA indicated that fluoboric acid pH was highly significant (p < 0.0001) with lower pH values resulting in higher flexural strength. Concentration alone was not a significant factor for flexural strengths, but there was a significant interaction between concentration and pH (p < 0.0001). Microscopy revealed that the acid-treated silver powder demineralized approximately 2 μm of dentin when used with no liner. The use of copal or polyamide varnishes eliminated most of this demineralization, but the use of a dentin adhesive liner resulted in some dislodgment and breakdown of the adhesive film by the acid.The results of this study indicate that this silver powder when treated with dilute fluoboric acid at a pH of approximately 1.0 can result in a filling material with strength equivalent to currently used conventional amalgam. The demineralization of tooth structure appears to be minimal and can be eliminated with the use of cavity liners.