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Journal of Dentistry Aug 2018The objectives were to investigate the hardness and chemical composition of sound, demineralized and pH-cycled bovine enamel and determine their influence on...
OBJECTIVES
The objectives were to investigate the hardness and chemical composition of sound, demineralized and pH-cycled bovine enamel and determine their influence on demineralization and remineralization behavior.
METHODS
Ninety-four, 5 × 5 × 2-mm bovine enamel specimens were demineralized using three different times [(24 h (n = 33), 48 h (n = 30), 96 h (n = 31)]. The specimens were then pH-cycled using either 367 ppm F sodium fluoride or deionized water. Knoop hardness (HK) and energy-dispersive X-ray spectroscopy (measured elements: Ca, P, F, C, Mg, N) were performed at three stages (sound, after demineralization, after pH-cycling) and transverse microradiography was performed after demineralization and pH-cycling. Comparisons were determined by ANOVA.
RESULTS
Results showed that HK, integrated mineral loss and lesion depth were significantly different between stages, demineralization times and treatments. The weight% of F at the surface was significantly affected by treatment, irrespective of demineralization time, while the Ca:P ratio of the enamel remained stable even after de- and remineralization protocols. The F in fluoride groups and the artificial saliva in non-fluoride groups were both able to induce enamel remineralization, indicating the protective effect of salivary pellicle against demineralization even in the absence of fluoride.
CONCLUSIONS
Harder specimens and those with greater surface F weight% were less susceptible to demineralization and were more likely to remineralize. However, the amount of surface Ca and P did not influence de- or remineralization behavior.
CLINICAL SIGNIFICANCE
This in vitro study can help clinicians better understand the caries process and the impact of the physical and chemical characteristics of enamel on its behavior during de- and remineralization. The over-the-counter fluoride toothpaste containing 1100 ppm-F was used, and was able to produce a mineralized enamel surface layer.
Topics: Animals; Cariostatic Agents; Cattle; Dental Caries; Dental Enamel; Fluorides; Hardness; Humans; Hydrogen-Ion Concentration; Tooth Demineralization; Tooth Remineralization
PubMed: 29738789
DOI: 10.1016/j.jdent.2018.05.002 -
Archives of Oral Biology Oct 2020The neonatal line (NNL) in enamel is hypomineralized, but quantitative data on the enamel component volumes of the NNL are lacking. This study aimed at quantifying the...
OBJETIVES
The neonatal line (NNL) in enamel is hypomineralized, but quantitative data on the enamel component volumes of the NNL are lacking. This study aimed at quantifying the variation in the mineral, organic, and water volumes at the NNL and in pre- and postnatal enamel.
MATERIALS AND METHODS
In buccal enamel longitudinal ground sections of exfoliated primary incisors (upper and lower; n = 17), the enamel component volumes were quantified at five histological sites (located at 40 μm intervals along a transversal line): the NNL, two sites in prenatal enamel, and two sites in postnatal enamel. Mineral volume was quantified using microradiography, and non-mineral volumes were quantified using polarizing microscopy.
RESULTS
Differences in component volumes between the NNL and pre- and postnatal enamel had high effect sizes (Hedge's G ranging from 0.89, for the water volume, to 1.88, for the mineral volume; power > 90 %). The distance from the NNL correlated with the normalized component volume: r = 0.459, 95 % CI = 0.274/0.612 (mineral); r = -0.504; 95 % CI= -0.328/-0.647 (organic), and r = -0.294; 95 % CI= -0.087/-0.476 (water). Approaching the NNL from postnatal enamel, the percentage differences in component volumes were: -1.93 to -3.22 % for the mineral volume, +21.26 to +35.42 % for the organic volume, and +3.86 to +6.03 % for the water volume. Towards postnatal enamel, the percentage differences had the opposite trend.
CONCLUSIONS
The enamel NNL is slightly hypomineralized with an increased organic volume one order of magnitude higher than the percentage differences in both mineral and water volumes.
Topics: Dental Enamel; Female; Humans; Microradiography; Minerals; Pregnancy; Tooth, Deciduous; Water
PubMed: 32736142
DOI: 10.1016/j.archoralbio.2020.104850 -
Dental Materials Journal 2016This study investigated the in vitro anti-demineralization effects of resin-based temporary filling materials containing surface prereacted glass-ionomer (S-PRG) filler...
This study investigated the in vitro anti-demineralization effects of resin-based temporary filling materials containing surface prereacted glass-ionomer (S-PRG) filler on dentin. Bovine root dentin specimens with a 3×3 mm experimental surface were divided into four treatment groups: DuraSeal (DU) as a control, S-PRG filler-free temporary material (S0), material containing 10% (S10) and 20% (S20) S-PRG filler. Each material was applied to 3×2 mm of the experimental surface, and the specimens were immersed in 8% methylcellulose gel demineralization system for one week at 37˚C. Mineral profiles and integrated mineral loss (IML) of lesions induced on the surface (3×1 mm) adjacent to the materials were computed by transversal microradiography. S10 and S20 yielded thick surface layers and shallow lesion bodies, with significantly lower IML than DU and S0 (p<0.05, Tukey's test). These findings indicate that temporary filling resin-based materials containing over 10% of S-PRG filler content have anti-demineralization effects on adjacent dentin.
Topics: Animals; Cattle; Composite Resins; Dentin; Glass Ionomer Cements; In Vitro Techniques; Materials Testing; Surface Properties; Tooth Remineralization; Tooth Root; X-Ray Microtomography
PubMed: 26830825
DOI: 10.4012/dmj.2015-135 -
Scientific Reports Jun 2022Assessment of enamel subsurface lesion remineralisation is essential for the evaluation of novel remineralisation technologies. The gold standard to assess subsurface...
Assessment of enamel subsurface lesion remineralisation is essential for the evaluation of novel remineralisation technologies. The gold standard to assess subsurface mineral gain of enamel lesions is transverse microradiography (TMR). However, some studies have utilised surface microhardness (SMH) to evaluate efficacy of remineralisation agents. The aim of this study was to assess remineralisation of enamel subsurface lesions using TMR and SMH after in vitro treatment with calcium-containing technologies, and to test correlation between the TMR and SMH measurements. The parameters obtained from the TMR and SMH analyses of enamel subsurface remineralisation were not significantly correlated. Furthermore, the enamel subsurface remineralisation as measured by TMR was significantly correlated with the water-soluble calcium concentration of the remineralisation products. Scanning electron microscopy revealed surface precipitates formed by specific remineralisation treatments obfuscated accurate assessment of remineralisation by SMH. It was concluded that TMR is a more appropriate method for analysis of enamel subsurface remineralisation, and that SMH values of remineralised enamel should be interpreted with caution. Using TMR the level of remineralisation (%R) by the different technologies was CPP-ACP/F (31.3 ± 1.4%); CPP-ACP (24.2 ± 1.4%); CaSO/KHPO/F (21.3 ± 1.4%); f-TCP/F (20.9 ± 1.0%); Nano-HA/F (16.3 ± 0.3%); Nano-HA (15.3 ± 0.6%) and F alone control (15.4 ± 1.3%).
Topics: Calcium; Calcium, Dietary; Cariostatic Agents; Microradiography; Minerals; Tooth Remineralization
PubMed: 35701508
DOI: 10.1038/s41598-022-13905-8 -
Antimicrobial Agents and Chemotherapy May 2019Biofilm control is a critical approach to the better management of dental caries. Antimicrobial small molecules have shown their potential in the disruption of oral...
Biofilm control is a critical approach to the better management of dental caries. Antimicrobial small molecules have shown their potential in the disruption of oral biofilm and control of dental caries. The objectives of this study were to examine the antimicrobial activity and cytotoxicity of a newly designed small-molecule compound, ZY354. ZY354 was synthesized, and its cytotoxicity was evaluated in human oral keratinocytes (HOK), human gingival epithelial cells (HGE), and macrophages (RAW) by CCK-8 assays. Minimal inhibitory concentrations (MICs), minimum bactericidal concentrations (MBCs), minimum biofilm inhibition concentrations (MBICs), and minimum biofilm reduction concentrations (MBRCs) of ZY354 against common oral streptococci (i.e., , , and ) were determined by microdilution method. The exopolysaccharide (EPS)/bacterium ratio and the dead/live bacterium ratio in the ZY354-treated multispecies biofilms were determined by confocal laser scanning microscopy, and the microbial composition was visualized and quantified by fluorescent hybridization and quantitative PCR (qPCR). The demineralizing activity of ZY354-treated biofilms was evaluated by transverse microradiography. The results showed that ZY354 exhibited low cytotoxicity in HOK, HGE, and RAW cells and exhibited potent antimicrobial activity against common oral streptococci. The EPS and the abundance of were significantly reduced after ZY354 treatment, along with an increased dead/live microbial ratio in multispecies biofilms compared to the level with the nontreated control. The ZY354-treated multispecies biofilms exhibited reduced demineralizing activity at the biofilm/enamel interface. In conclusion, the small-molecule compound ZY354 exhibits low cytotoxicity and remarkable antimicrobial activity against oral streptococci, and it may have a great potential in anticaries clinical applications.
Topics: Anti-Infective Agents; Biofilms; Dental Caries; Molecular Structure; Streptococcus; Streptococcus gordonii; Streptococcus mutans; Streptococcus sanguis
PubMed: 30858201
DOI: 10.1128/AAC.02414-18 -
PloS One 2014Dental caries is the most prevalent disease encountered by people of all ages around the world. Chemical changes occurring in the oral environment during the caries...
Dental caries is the most prevalent disease encountered by people of all ages around the world. Chemical changes occurring in the oral environment during the caries process alter the crystallography and microstructure of dental enamel resulting in loss of mechanical function. Little is known about the crystallographic effects of demineralization and remineralization. The motivation for this study was to develop understanding of the caries process at the crystallographic level in order to contribute towards a long term solution. In this study synchrotron X-ray diffraction combined with scanning electron microscopy and scanning microradiography have been used to correlate enamel crystallography, microstructure and mineral concentration respectively in enamel affected by natural caries and following artificial demineralization and remineralization regimes. In particular, the extent of destruction and re-formation of this complex structure has been measured. 2D diffraction patterns collected at the European Synchrotron Radiation Facility were used to quantify changes in the preferred orientation (crystallographic texture) and position of the (002) Bragg reflection within selected regions of interest in each tooth slice, and then correlated with the microstructure and local mineral mass. The results revealed that caries and artificial demineralization cause a large reduction in crystallographic texture which is coupled with the loss of mineral mass. Remineralization restores the texture to the original level seen in healthy enamel and restores mineral density. The results also showed that remineralization promotes ordered formation of new crystallites and growth of pre-existing crystallites which match the preferred orientation of healthy enamel. Combining microstructural and crystallographic characterization aids the understanding of caries and erosion processes and assists in the progress towards developing therapeutic treatments to allow affected enamel to regain structural integrity.
Topics: Crystallography; Dental Caries; Dental Enamel; Humans; Microradiography; Microscopy, Electron, Scanning; Minerals; Molar; Reference Values; Synchrotrons; Tooth Demineralization; Tooth Remineralization; X-Ray Diffraction
PubMed: 25360532
DOI: 10.1371/journal.pone.0108879 -
Microorganisms Aug 2020While probiotics have been tested for their anti-caries effect in vitro and also clinically, there is a lack of understanding of their effects on complex dental...
While probiotics have been tested for their anti-caries effect in vitro and also clinically, there is a lack of understanding of their effects on complex dental biofilms. We assessed two probiotics, and , on a continuous-cultured model containing , and . Cariogenic biofilms were grown on bovine enamel specimens and daily challenged with or whole culture (LC/SC) or cell-free supernatant (LS/SS) or medium only (negative control, NC) ( = 21/group) for 10 days. Biofilm was assessed via counting colony-forming units, quantitative polymerase chain reaction, and fluorescence in situ hybridization. Caries activity was determined by pH measurements and by assessing mineral loss (ΔZ) using transverse microradiography. Both LC and SC significantly reduced total and strain-specific cariogenic bacterial numbers ( < 0.05). ΔZ was reduced in LC (mean ± SD: 1846.67 ± 317.89) and SC (3315.87 ± 617.30) compared to NC (4681.48 ± 495.18, < 0.05). No significant reductions in bacterial numbers and ΔZ was induced by supernatants. Biofilm architecture was not considerably affected by probiotic applications. Viable probiotics and , but not their culture supernatants, could reduce the caries activity of multi-species biofilms .
PubMed: 32825575
DOI: 10.3390/microorganisms8091272 -
Journal of International Society of... 2022To evaluate self-assembling peptides (SAP) for caries prevention and arrest in primary tooth enamel .
OBJECTIVES
To evaluate self-assembling peptides (SAP) for caries prevention and arrest in primary tooth enamel .
MATERIALS AND METHODS
Overall, 180 extracted primary teeth were used. In the prevention experiment ( = 20 samples per group), self-assembling peptide for prevention (SAPP), fluoride varnish/mouthwash (FV/FMW), casein-phosphopeptide amorphous-calcium phosphate (CPP-ACP), and nanohydroxyapatite (nHA) were applied. Samples were subjected to a demineralizing pH cycling for 14 days. In the arrest experiment ( = 15/group), 60 samples were pre-demineralized; induced lesions were treated using self-assembling peptide for repair (SAPR), FV, CPP-ACP plus fluoride, and resin infiltration (RI) and submitted to pH cycling. Mineral loss and its differences as well as lesion depth were determined using transversal microradiography. Numerical data were tested for normality using Shapiro-Wilk's test and were compared using Kruskal-Wallis test followed by pairwise comparisons utilizing multiple Mann-Whitney U tests with Bonferroni correction. The significance level was set at < 0.05 within all tests.
RESULTS
FV (median: -46.3 [interquartile range: 175.52] vol% × µm) and FMW (-33.35 [124.65] vol% × µm) prevented caries significantly more effectively than all other groups ( < 0.001), which did not show significant preventive effects. RI (median: 4949.70 [1637.20] vol% × µm) and FV (median = 6076.05 [5190.08] vol% × µm) arrested lesions, whereas SAPR and CPP-ACPF did not show such arrest.
CONCLUSIONS
FV and FMW showed the largest caries-preventive effect, whereas RI and FV arrested lesion progression in primary tooth enamel .
PubMed: 35281691
DOI: 10.4103/jispcd.JISPCD_257_21 -
Journal of Applied Oral Science :... 2022Quantification of collagen degradation is an important parameter to evaluate dentin caries for preventive aid.. Evaluate preventive methods against root collagen...
OBJECTIVES
Quantification of collagen degradation is an important parameter to evaluate dentin caries for preventive aid.. Evaluate preventive methods against root collagen degradation by the hydroxyproline assay (HYP) and microradiography technique (MRT).
METHODOLOGY
Five bovine root dentin blocks were obtained and subjected to an artificial demineralization process by acetate buffer (pH 5) to induce carious lesion formation. Samples were subjected to the following therapeutic treatments: 1) 0.12% chlorhexidine for 1 min, 2) 2% fluoride for 1 min, 3) Nd:YAG Laser (400 μm diameter optical fiber, 10 Hz frequency, 60 mJ/pulse energy, 48 J/cm2 energy density, in noncontact mode for 10 s), 4) deionized water (control) for 1 min, 5) MRT control group (without treatment and removal of collagen). Samples were exposed to degradation by a collagenase enzyme for five days. The enzyme solution was collected, by colorimetry in a spectrophotometer, from the collagen matrix for the hydroxyproline release analysis. The same samples were subjected to an additional two days of demineralization to induce the progression of mineral loss. Samples were analyzed by MRT for the visualization of their degraded areas (estimation of lesion depth and mineral loss). ANOVA was applied to compare hydroxyproline release rates. MRT data were subjected to the Kruskal-Wallis test, followed by the Dunn's test. Comparisons between the initial five-day and the subsequent two-day demineralization processes were performed by repeated t-test or Wilcoxon (p<0.05) measurements.
RESULTS
The amount of HYP released from the dentin samples failed to show significant differences among the groups (p=0.09). Fluoride and chlorhexidine were able to interact with the samples, reducing the progression of dentin caries after removal of the demineralized organic matrix. CHX was the only treatment able to show significant lower lesion depth than the negative control.
CONCLUSION
Chlorhexidine and fluoride were effective in reducing root caries progression.
Topics: Animals; Cattle; Chlorhexidine; Dentin; Fluorides; Root Caries; Tooth Demineralization
PubMed: 35293423
DOI: 10.1590/1678-7757-2021-0496 -
Microorganisms Apr 2021Caries preventive varnishes containing only fluoride might differ from those containing a combination of fluoride and antimicrobial components in terms of mineralization...
Caries preventive varnishes containing only fluoride might differ from those containing a combination of fluoride and antimicrobial components in terms of mineralization properties and their impact on the cariogenic biofilm. We compared a fluoride and a fluoride + chlorhexidine (CHX)/cetylpyridinium chloride (CPC) varnish on root caries formation in vitro. One hundred bovine root dentin samples were allocated to five groups ( = 20/group): (1) 7700 ppm fluoride varnish (Fluorprotector S (F)), (2) experimental placebo varnish for F (F-P), (3) 1400 ppm fluoride + 0.3% CHX/0.5% CPC varnish (Cervitec F (CF)), (4) experimental placebo varnish for CF (CF-P), (5) untreated control. Cariogenic challenge was provided using a multi-station, continuous-culture 3-species ( (SM), (LR), (AN)) biofilm model for 10 days. Mineral loss (ΔZ) was evaluated using transversal microradiography and bacterial counts in the biofilm assessed as colony-forming units. Fluorescence in situ hybridization (FISH) and confocal microscopy were performed to assess the three-dimensional biofilm architecture. Mean ± SD (vol% × μm) ΔZ was significantly lower for F (9133 ± 758) and CF (9835 ± 1677) compared to control (11362 ± 919) ( < 0.05), without significant differences between F and CF. SM counts were significantly lower and LR counts significantly higher in F- and CF-biofilms compared to control. AN counts were significantly higher in the F-biofilms than in all other groups. According to FISH, SM and LR invaded dentinal tubules only in the control-group. In the CF-group, the basal biofilm layer did not contain SM and AN. Both F and CF varnishes had similar caries-preventive effects and a considerable impact on biofilm structure and composition.
PubMed: 33916105
DOI: 10.3390/microorganisms9040737