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Background: Dental caries remains a significant global health problem. One of the fundamental mechanisms underlying the development and progression of dental caries is the dynamic process of demineralisation/remineralisation. In vitro models have played a critical role in advancing our understanding of this process and identifying potential interventions to prevent or arrest dental caries. This literature review aims to provide a structured oversight of in vitro mineralisation models which have been used to study the tooth demineralisation/remineralisation process. Methods: Publications from 2019 to 2023 were screened to identify articles reporting the use of in vitro models to study the demineralisation/remineralisation of tooth caries. The included studies were methodologically assessed for their information on (i) substrate, (ii) lesion formation, and (iii) mineralisation models. Results: The most reported substrates used in the studies were human teeth along with bovine incisors. Acetic/lactic buffers were the most common solutions to induce caries lesions. pH cycling was the most frequently used mineralisation model for simulating the daily change within the oral environment. This review discussed the advantages and limitations of various approaches. Conclusions: Standardisation of in vitro mineralisation models is crucial for enabling effective comparison between studies and advancing caries research. [ABSTRACT FROM AUTHOR]

Purpose: To synthesise and characterise nanosilver sodium fluoride (NSSF) and assess the effect of applying this formulation in vitro on artificially demineralised root dentin lesions, compared with the application of silver diamine fluoride (SDF), sodium fluoride (NAF) or no treatment, in terms of mechanical, chemical and ultrastructural properties. Materials and Methods: NSSF was prepared using 0.5 wt% chitosan solution. On 40 extracted human molars, the buccal aspect of the cervical thirds of roots were prepared and divided into 4 groups of 10 each: control (no treatment), NSSF, SDF and NaF (n = 10). The specimens were examined using scanning electron microscopy (SEM), atomic force microscopy (AFM), and x-ray photoelectron spectroscopy (XPS). Fourier transform infrared spectroscopy (FTIR), surface and cross-sectional microhardness and nano-indentation tests were performed to determine the mineral and carbonate content, microhardness, and nanohardness, respectively. Statistical analysis was performed to determine the differences between the different treatment groups for the set parameters using parametric and non-parametric tests. Tukey's and Dunnet's T3 post-hoc tests were further used for multiple comparisons between groups (α = 0.05). Results: The control group (no treatment) was found to have statistically significantly lower mean scores for surface and cross-sectional microhardness compared with all other test groups (NaF, NSSF and SDF) (p < 0.05). Spearman's rank correlation test showed statistically insignificant differences between the mineral-to-matrix ratio (M:M) and carbonate content of all groups (p < 0.05). Conclusions: Treatment of root lesions with NSSF yielded comparable results to SDF and NaF under in-vitro conditions. [ABSTRACT FROM AUTHOR]

Abstract Chemical leaching of coals would be required to produce cleaner coals for some special applications where physical beneficiation may not be effective enough. This would also help in recovering Li and rare earth metals besides in the sequestration of CO2. About 20 Indian coals having complexly distributed moderate to high ash contents were sequentially treated with various alkali–acid such as NaOH-HCl, HF, HCl, HCl-HF, and NaOH-HCl-HF leaching. This aimed to establish and design the best stepwise sequential process for the highest degree of demineralisation through a chemical leaching process. Kinetics and process intensification studies were carried out. More than 80% demineralisation of Madhaipur and Neemcha coals was observed using the best sequential treatment designed presently. The repeated stepwise treatment of the alkali and the acid was also studied, which was found to significantly enhance the degree of demineralisation of coals. The integrated process of alkali–acid leaching followed by solvent extraction (Organo-refining) and vice versa of the treated coal was also studied for producing cleaner coals.

This study aims to investigate whether toothbrushes with fluoride-infused bristles have any (re)mineralisation effects on bovine enamel. Bovine incisors (N = 160) were extracted, and the buccal side of the crown was cut into dimensions of ~5 mm × 5 mm with a low-speed saw. These specimens were randomly allocated into four groups: half (80 teeth) were stored in demineralising solution (DM), and the other half were stored in deionised water (DW) for 96 h. Then, they were brushed with a force of 2.0 ± 0.1 N for five min with a manual toothbrush with either fluoride-infused (TF) or regular (TR) bristles. Microhardness (Vickers), X-ray diffraction (XRD), energy-dispersive X-ray spectroscopy (EDS), and scanning electron microscopy (SEM) were used to investigate the surfaces of the bovine enamel specimens before and after brushing. Two-way ANOVA was used to analyse the hardness data, and the pairwise comparison method was used to analyse the Ca/P ratio, for each group at α = 0.05. The results show that brushing with either of these toothbrushes increased the Vickers microhardness on DM and DW enamel (p < 0.001), whereas hydroxyapatite was revealed in all groups by XRD. The DM samples showed a significant increase (p < 0.05) in the Ca/P ratios after brushing with TR and TF. Conversely, under DW conditions, these ratios decreased significantly after brushing. In terms of the F atomic%, TF increased significantly. SEM revealed mineral deposition in the DM groups after toothbrushing. To conclude, toothbrushing effectively induces the microhardness of sound and demineralised enamel, while fluoride-infused bristles might be able to retain fluoride on the enamel surface. [ABSTRACT FROM AUTHOR]

Chemical leaching of coals would be required to produce cleaner coals for some special applications where physical beneficiation may not be effective enough. This would also help in recovering Li and rare earth metals besides in the sequestration of CO2. About 20 Indian coals having complexly distributed moderate to high ash contents were sequentially treated with various alkali–acid such as NaOH-HCl, HF, HCl, HCl-HF, and NaOH-HCl-HF leaching. This aimed to establish and design the best stepwise sequential process for the highest degree of demineralisation through a chemical leaching process. Kinetics and process intensification studies were carried out. More than 80% demineralisation of Madhaipur and Neemcha coals was observed using the best sequential treatment designed presently. The repeated stepwise treatment of the alkali and the acid was also studied, which was found to significantly enhance the degree of demineralisation of coals. The integrated process of alkali–acid leaching followed by solvent extraction (Organo-refining) and vice versa of the treated coal was also studied for producing cleaner coals. [ABSTRACT FROM AUTHOR]

Background: Dental caries remains a significant global health problem. One of the fundamental mechanisms underlying the development and progression of dental caries is the dynamic process of demineralisation/remineralisation. In vitro models have played a critical role in advancing our understanding of this process and identifying potential interventions to prevent or arrest dental caries. This literature review aims to provide a structured oversight of in vitro mineralisation models which have been used to study the tooth demineralisation/remineralisation process. Methods: Publications from 2019 to 2023 were screened to identify articles reporting the use of in vitro models to study the demineralisation/remineralisation of tooth caries. The included studies were methodologically assessed for their information on (i) substrate, (ii) lesion formation, and (iii) mineralisation models. Results: The most reported substrates used in the studies were human teeth along with bovine incisors. Acetic/lactic buffers were the most common solutions to induce caries lesions. pH cycling was the most frequently used mineralisation model for simulating the daily change within the oral environment. This review discussed the advantages and limitations of various approaches. Conclusions: Standardisation of in vitro mineralisation models is crucial for enabling effective comparison between studies and advancing caries research.

The management of root caries remains a challenge for clinicians due to its unique anatomical location and structure. There is increasing interest in utilising artificial root caries lesions to develop new strategies for remineralisation. An ideal protocol has not yet been agreed upon. The aim of this review is to provide a structured overview of previously reported in vitro root caries models. The literature was screened and mined for information mainly on substrate selection, model systems utilised, and variables used in the models. Human roots (60%) were the most frequently used substrates, followed by bovine roots (40%). Chemical models (69%) were the most frequently utilised model systems, followed by microbiological models (27%), to form root caries lesions. Acetate buffer solution (80%), pH 5.0 or above (40%), and a demineralisation time of five days (25%) were the common variables used in the chemical systems, while mono-species biofilm was most frequently used (73%) in microbiological models and Streptococcus mutans was the most common bacterial strain utilised in these models (80%). This review highlights the variability amongst the experimental approaches, discusses the advantages and limitations of these approaches, and emphasises that standardisation of experimental conditions along with sustained research will benefit root caries research. [ABSTRACT FROM AUTHOR]

This study aims to investigate whether toothbrushes with fluoride-infused bristles have any (re)mineralisation effects on bovine enamel. Bovine incisors (N = 160) were extracted, and the buccal side of the crown was cut into dimensions of ~5 mm × 5 mm with a low-speed saw. These specimens were randomly allocated into four groups: half (80 teeth) were stored in demineralising solution (DM), and the other half were stored in deionised water (DW) for 96 h. Then, they were brushed with a force of 2.0 ± 0.1 N for five min with a manual toothbrush with either fluoride-infused (TF) or regular (TR) bristles. Microhardness (Vickers), X-ray diffraction (XRD), energy-dispersive X-ray spectroscopy (EDS), and scanning electron microscopy (SEM) were used to investigate the surfaces of the bovine enamel specimens before and after brushing. Two-way ANOVA was used to analyse the hardness data, and the pairwise comparison method was used to analyse the Ca/P ratio, for each group at α = 0.05. The results show that brushing with either of these toothbrushes increased the Vickers microhardness on DM and DW enamel (p < 0.001), whereas hydroxyapatite was revealed in all groups by XRD. The DM samples showed a significant increase (p < 0.05) in the Ca/P ratios after brushing with TR and TF. Conversely, under DW conditions, these ratios decreased significantly after brushing. In terms of the F atomic%, TF increased significantly. SEM revealed mineral deposition in the DM groups after toothbrushing. To conclude, toothbrushing effectively induces the microhardness of sound and demineralised enamel, while fluoride-infused bristles might be able to retain fluoride on the enamel surface.

Purpose: During biofilm formation, bacterial species do not attach directly onto the enamel surface, but rather onto the salivary pellicle. Salivary pellicle modification with casein and mucin can hinder erosive demineralisation of the enamel, but it should also not promote bacterial adhesion. The aim of our study was to assess whether salivary pellicle modification with casein, or mucin, or a mixture of both proteins (casein and mucin) influence bacterial adhesion, biofilm diversity, metabolism and composition, or enamel demineralisation, after incubation in: (a) a single bacterial model; (b) a five-species biofilm model; or (c) biofilm reformation using the five-species biofilm model after removal of initial biofilm with toothbrushing.Materials and Methods: Enamel specimens were prepared from human molars. Whole-mouth stimulated human saliva was used for pellicle formation. Four pellicle modification groups were established: control (non-modified pellicle); casein - modified with 0.5% casein; mucin - modified with 0.5% mucin; casein and mucin - modified with 0.5% casein and 0.5% mucin. Bacterial adhesion, biofilm diversity, metabolic activity, biofilm mass, and demineralisation (surface hardness) of enamel were assessed after incubation in bacterial broths after 6 h or 24 h.Results: After 24 h incubation in the five-species biofilm model, the mucin group presented significantly lower biofilm mass than the control (p = 0.028) and the casein and mucin (p = 0.030) groups. No other differences between the groups were observed in any of the other experimental procedures.Conclusion: Pellicle modification with casein and mucin does not promote in vitro bacterial biofilm formation. [ABSTRACT FROM AUTHOR]

Purpose: The purpose of this study was to perform an in vitro evaluation of the protective effects of anticavity agents applied to enamel, by themselves and in combination with Er:YAG.Materials and Methods: In this study 150 extracted third molars were used. Measurements were made using DIAGNOdent, and samples with scores of 0-13 were included in the study. These were divided into 15 groups (n = 20). Use of the agents sodium fluoride (NaF), tricalcium phosphate (Ca3PO4), titanium tetrafluoride (TiF4), Tooth Mousse (CPP-ACP), MI Paste Plus (CPP-ACP), and NovaMin (bioactive glass), individually and then in combination with Er:YAG laser, was assessed based on their effects on microhardness values. After treatment, the groups were exposed to a demineralisation solution. Statistical analyses were conducted using SPSS 20.0 package software.Results: The highest test result value was observed in the TFL (TiF4/Er:YAG laser) group. Statistically significant differences were determined among all the groups (p <0.05). When the groups in which the agents were applied alone were compared with those involving combined use of Er:YAG laser, combined use provided significantly higher microhardness values, with the exception of the TML group (Tooth Mousse/Er:YAG laser) (p <0.05).Conclusion: Within the limits of this study, the combined use of remineralisation agents and Er:YAG laser elicited better results than using the agents alone. The most effective remineralisation agent was TiF4/Er:YAG laser, which may be considered an alternative method for protecting the enamel against demineralisation. [ABSTRACT FROM AUTHOR]

Calcium oxalate (CaOx) is a minor constituent that is predominant in wild silk cocoons. While CaOx is abundantly accumulated in wild silkworm cocoons, domesticated silkworms have acquired and acclimated to less CaOx crystal deposition. Although CaOx is thought to be counterproductive in the cocoon, it plays a vital role in the protection, water resistance, CO2 gating, reflection, thermal insulation, etc. of the cocoon. In this review, recent advances in our understanding of CaOx function in wild silk cocoons, CaOx biosynthesis in host plants, and CaOx transport and deposition to cocoons are discussed. The constraints of CaOx in reeling wild silk cocoons are also discussed with the aspect of demineralization for commercial exploitation of wild silk fibres. This review presents a summary of reliable findings as well as potential research avenues for biologists interested in the commercialization of wild cocoons. [ABSTRACT FROM AUTHOR]

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Collagen is the building block for the extracellular matrix in bone, teeth and other fibrous tissues. Osteogenesis imperfecta (OI), or brittle bone disease, is a heritable disorder that results from defective collagen synthesis or metabolism, resulting in bone fragility. The dental manifestation of OI is dentinogenesis imperfecta (DI), a genetic disorder that affects dentin structure and clinical appearance, with a characteristic feature of greyish-brown discolouration. The aim of this study was to conduct a systematic review to identify and/or define any ultrastructural changes in dentinal collagen in DI. Established databases were searched: Cochrane Library, OVID Embase, OVID Medline and PubMed/Medline. Search strategies included: Collagen Ultrastructure, DI and OI. Inclusion criteria were studies written in English, published after 1990, that examined human dental collagen of teeth affected by DI. A Cochrane data extraction form was modified and used for data collection. The final dataset included seventeen studies published from 1993 to 2021. The most prevalent findings on collagen in DI teeth were increased coarse collagen fibres and decreased fibre quantity. Additional findings included changes to fibre orientation (i.e., random to parallel) and differences to the fibre organisation (i.e., regular to irregular). Ultrastructural defects and anomalies included uncoiled collagen fibres and increased D-banding periodicity. Studies in collagen structure in DI reported changes to the surface topography, quantity, organisation and orientation of the fibres. Moreover, ultrastructural defects such as the packing/coiling and D-banding of the fibrils, as well as differences in the presence of other collagens are also noted. Taken together, this study provides an understanding of the changes in collagen and its impact on clinical translation, paving the way for innovative treatments in dental treatment. [ABSTRACT FROM AUTHOR]

Purpose: To compare adhesive flash-free (FF) and adhesive pre-coated (APC) brackets in terms of plaque retention and constituents, gingival biomarkers and enamel demineralisation.Materials and Methods: Fifty adolescents (mean age ± SD; 14.23 ± 0.15 years, age range: 13-18 years) were randomly distributed to receive FF or APC ceramic brackets in the maxillary right or left quadrant. Plaque and gingival indices, quantitative light-induced fluorescence (QLF) imaging, gingival crevicular fluid (GCF) and plaque sampling were performed at baseline and at 1, 2 and 3 months (T0, T1, T2, T3) after bracket placement. QLF was repeated following debonding. GCF samples were analysed for biomarkers by immunoassay and plaque by real-time PCR for bacterial content. Data were analysed using the Wilcoxon test on dependent samples and 2-tailed ANOVA.Results: Plaque index, gingival index and fluorescence changes were similar for the two adhesive-bracket systems. GCF volumes and interleukin (IL)-1ß levels increased compared to baseline (p < 0.05). IL-17A levels and RANKL:OPG ratios were similar in both groups. In dental plaque, Aggregatibacter actinomycetemcomitans numbers were higher in the APC group at T3. Fusobacterium nucleatum (Fn) counts statistically significantly decreased at T1 and T3 as compared to T0 in the FF group (p < 0.05 and p < 0.01, respectively), whereas Fn counts increased in the APC group at T3 (p < 0.01). Porphyromonas gingivalis, Streptococcus oralis and total bacterial counts were significantly higher in the APC group than in the FF group at T3 (p < 0.01).Conclusion: In orthodontic patients with good oral hygiene, the quantity of plaque on adhesive flash-free brackets and conventional brackets did not differ, but the constituents of plaque differed, with less pathogenic bacteria detected around adhesive flash-free brackets. Further studies also including a group of individuals with poor oral hygiene and longer follow-up periods may better clarify the issue. [ABSTRACT FROM AUTHOR]

Purpose: To measure the demineralisation changes on human deciduous enamel produced by pH cycling after preventive treatment with Er:YAG laser irradiation, fluoride varnish application and a combination of the two.Materials and Methods: Sixty extracted human anterior primary teeth were assigned to six groups (n = 10). Group C: untreated; group L: Er:YAG laser; group TCP-NaF: Clinpro White (5% sodium fluoride and modified tricalcium phosphate); group CPP-ACP-NaF: MI varnish (5% sodium fluoride with casein phosphopeptide-amorphous and calcium phosphate); group L+TCP-NaF: Er:YAG + 5% sodium fluoride + modified tricalcium phosphate; group L+ CPP-ACP-NaF: Er:YAG + 5% sodium fluoride with casein phosphopeptide-amorphous and calcium phosphate. The samples were subjected to a 10-day pH-cycling regimen to create caries-like lesions, with 8 h in demineralising solution and 16 h in remineralising solution at 37°C. Enamel demineralisation was evaluated by laser fluorescence (DIAGNOdent) before and after pH cycling. The Mann-Whitney U-test and Wilcoxon tests were performed with statistical significance set at p ≤ 0.05.Results: The Wilcoxon test revealed statistically significant differences at baseline and after pH cycling in groups C (p = 0.02), L (p = 0.034) and L+TCP-NaF (p = 0.025) and the lowest percentage of healthy tooth substance compared to the other groups.Conclusions: The results suggest that the treatment protocols employed in groups TCP-NaF, CPP-ACP-NaF, and L+ CPP-ACP-NaF had similar effects in terms of preventing demineralisation, as reflected in a higher percentage of healthy dental structure maintained. Hence, these treatments are recommended for clinical use as an effective preventive measure. [ABSTRACT FROM AUTHOR]

IntroductionFluoride plays a major role in inhibiting enamel dissolution and promoting fluorapatite formation. Porous hydroxyapatite (HAP) discs can be used as an enamel analogue in artificial demineralisation/remineralisation studies.MethodThe aim of the study was to monitor the fluoride-mineral phases formed on HAP surfaces as a function of fluoride concentration ([F−]) under demineralising conditions, using 19F magic angle spinning nuclear magnetic resonance (MAS-NMR) spectroscopy, and compare the results with a previous study using an enamel substrate. Porous HAP blocks were immersed in demineralisation solutions (0.1 M acetic acid, pH 4.0) with increasing [F−] (0–1450 ppm).ResultsAt below 50 ppm [F−], 19F MAS-NMR showed fluoride-substituted apatite formation; above 50 ppm [F−], calcium fluoride (CaF2) was formed in increasing proportions. These results mirrored those of previous similar studies with an enamel substrate. Further increases in fluoride caused no further measurable reduction in demineralisation but increased the proportion of CaF2 formed. The total calcium concentration [Ca] and total phosphorus [P] concentrations in the solution were measured by inductively coupled plasma atomic emission spectroscopy. At high fluoride concentrations, the solution total [P] increased, and the molar Ca:P ratios decreased to values consistent with the formation of CaF2. However, Ca:P ratios found at low [F−] were higher than those in the previous enamel study and consistent with the formation of a partially fluoridated apatite.ConclusionsUnder demineralising conditions, CaF2 formed on HAP at an [F−] of 50 ppm and above, whereas fluoridated apatite formed at an [F−] below 50 ppm. The results were consistent with those obtained when an enamel substrate was used.

The management of root caries remains a challenge for clinicians due to its unique anatomical location and structure. There is increasing interest in utilising artificial root caries lesions to develop new strategies for remineralisation. An ideal protocol has not yet been agreed upon. The aim of this review is to provide a structured overview of previously reported in vitro root caries models. The literature was screened and mined for information mainly on substrate selection, model systems utilised, and variables used in the models. Human roots (60%) were the most frequently used substrates, followed by bovine roots (40%). Chemical models (69%) were the most frequently utilised model systems, followed by microbiological models (27%), to form root caries lesions. Acetate buffer solution (80%), pH 5.0 or above (40%), and a demineralisation time of five days (25%) were the common variables used in the chemical systems, while mono-species biofilm was most frequently used (73%) in microbiological models and Streptococcus mutans was the most common bacterial strain utilised in these models (80%). This review highlights the variability amongst the experimental approaches, discusses the advantages and limitations of these approaches, and emphasises that standardisation of experimental conditions along with sustained research will benefit root caries research.

Introduction: Enamel gets demineralised when they get exposed to acidic environment. Very common issue seen after orthodontic treatment is white spot lesion and also there is a chance of inflammation in periodontal fibres if the fixed lingual retainer is given to the patient. Furthermore, it enhances the plaque and calculus accumulation. So, to minimise these deleterious effects, lingual retainer is modified by surface coating with silver dioxide which shows anti-bacterial and anti-adhesive properties. Aim: Assessment of anti-adherent and anti-bacterial properties of silver dioxide (AgO2) surface modified Orthodontic lingual retainer against S.mutans. Materials and Methods: This cross-sectional study will use 60 orthodontic lingual retainer specimens. The samples will be divided into four groups for testing with 15 specimens in each group. The samples will be divided into four groups : two control groups with commercially available lingual retainer will be used for assessing anti-bacterial and anti-adhesion properties and other two will be of surface treated lingual retainer for testing. Bacterial strains will be taken with sample size 15 in each group then the preparation of photocatalytic silver dioxide‑coated orthodontic lingual retainer. Even coating will be ensured by sputtering technique and thickness of coating will be 50-60 nm. Chi-square test will be used to analyse differences in categorical variables. Expected outcome: The photocatalytic (AgO2) coated retainer will reduce the bacterial accumulation and adhesion. Conclusion: Surface modification of lingual retainers with photocatalytic AgO2 will reduce the bacterial adhesion which can be used to prevent the formation of dental plaque and demineralization orthodontic treatment, thereby preventing demineralization of enamel and periodontal breakdown.

Objective. The main objective of the study was to compare two different remineralising materials containing casein phosphopeptide-amorphous calcium phosphate, bioactive glass on enamel surface microhardness. Materials and Methods. Thirty premolars were used for specimen preparation. Group 1 (the control group) consisted of intact enamel samples, group 2: CPP-ACPF (Tooth Mousse Plus), group 3: bioenamel remineralising gel (Prevest DenPro). All specimens were subjected to demineralisation except the control group, followed by which remineralising agents were applied. A universal hardness tester was used to assess the surface microhardness of all samples. Results were analysed using one-way ANOVA test and comparison was analysed using Scheffe's post hoc least significant difference (LSD) test. Results. Both remineralising agents used in groups 2 and 3 have shown significant outcome in terms of improving the surface microhardness in comparison with the control group. Group 2 increased the enamel hardness by 8.34 where P = 0.023 whereas group 3 increased the hardness by 5.87, where P = 0.01. Conclusion. Group 2 has a superior hardness value than group 3; however, no statistically significant results were obtained between both the groups. [ABSTRACT FROM AUTHOR]

Objective: To evaluate the change in demineralisation depth (DD)and mineral density (MD) over time in primary teeth exposed to a demineralisation protocol with microcomputed tomography (microCT). Methods: Caries lesions were artificially induced on the labial surfaces of 9 primary incisors by way of a demineralisation protocol using 0.1 M lactic acid with 10% methylcellulose gel for 7 and 14 days. The specimens were scanned with microCT and CTAn software (Bruker, Billerica, MA, USA) was used to analyse the changes in DD and MD. Statistical analyses were performed using SPSS software (IBM, Armonk, NY, USA). Repeated analysis of variance (ANOVA) test and Pearson bivariate correlation were used and the level of significance was set at P < 0.05. Results: The DD ranged from 0.00 to 0.99 µm (mean ± standard deviation [SD] 0.70 ± 0.43 µm) at baseline, 11.18 to 29.5 µm (18.15 ± 5.23 µm) at 7 days and 18.00 to 55.30 µm (34.20 ± 8.70 µm) at 14 days. The MD for all specimens (n = 9) ranged from 1.48 to 1.76 g/cm³ (1.65 ± 0.08 g/cm³) at baseline, from 1.47 to 1.74 g/cm³ (1.62 ± 0.08 g/cm³) at 7 days demineralisation and 1.33 to 1.72 g/cm³ (1.54 ± 0.13 g/cm3) at 14 days. There were statistically significant differences in DD (P < 0.001) and MD (P = 0.016) between different durations of demineralisation. Conclusion: DD and MD change with time after being exposed to demineralising solution. MicroCT is a nondestructive method that allows repeated MD evaluations of the same sample. [ABSTRACT FROM AUTHOR]

Background: Demineralisation and remineralisation is a natural process in tooth enamel. It is influenced by the content of calcium and phosphorus in saliva, which concentrations are affected by the consumption of food, including formula milk. Demineralisation and remineralisation determine the roughness and hardness of the enamel surface. Purpose: This study compared the effect of formula milk on the roughness and hardness of tooth enamel. Methods: Maxillary premolar extracted teeth were demineralised with 37% phosphoric acid for 90 seconds and then divided into four treatment groups. For four days, the teeth were immersed twice a day in cow formula for five and ten minutes (Group I and II) and soy formula for five and ten minutes (Group III and IV). Before and after the immersion in milk, the teeth were submerged in artificial saliva. The enamel surface roughness and hardness were measured three times using a surface roughness tester and a Vickers microhardness tester, before and after demineralisation and after immersion in milk. Data were analysed using Kruskal–Wallis and post hoc Mann–Whitney tests. Results: There was no significant difference (p=0.88) observed in the roughness reduction among the treatment groups. The highest increase in hardness was noted for the ten-minute cow formula milk group (93.27 ± 16.00). The increase of hardness was higher after immersion for ten minutes. A substantial difference (p=0.03) was seen in the increase of hardness between the treatment groups. Conclusion: Immersion in cow and soy formula milk for five and ten minutes does not reduce the enamel roughness, but it increases the enamel hardness.

الملخص: أهداف البحث: في هذه الدراسة في المختبر، قمنا بتحليل إمكانية قدرة مادة البروبوليسعلى إعادة بناء طبقة المينا. طرق البحث: تم تقسيم ٢٠ عينة من المينا بشكل عشوائي إلى مجموعتين (كل مجموعة ١٠) المجموعة ١ (التحكم): حيث تم دهن عينات المينا باللعاب الصناعي، والمجموعة ٢: تم دهن عينات المينا بزيت البروبوليس. تعرضت جميع عينات المينا لنزع المعادن عن طريق تعريضها إلى حمض الستريك بنسبة تركيز ٦٪ (الرقم الهيدروجيني = ٢.٢) لمدة ٥ دقائق. وتم إجراء تفريش للأسنان داخل آلة محاكاة تفريش الأسنان باستخدام فرش الأسنان اليدوية وتلقت كل عينة ٥٠٠٠ ضربة طولية. تم إجراء تحليل الصلابة الدقيقة للسطح على كل عينة على ثلاث فترات مختلفة قبل نزع المعادن (الأساس)، وبعد نزع المعادن، وبعد إعادة المعادن للحصول على عدد صلابة فيكرز. النتائج: أظهرت النتائج تحسنا في الصلابة الدقيقة لعينات المينا بعد تفريش الأسنان بزيت البروبوليس مقارنة بالعينات التي تم تفريشها فقط. وبالنسبة لمجموعة التحكم، كان متوسط خط الأساس لعدد صلابة فيكرز هو ٥٨٣.٦٦، الذي انخفض إلى ١١٦.٢٣ بعد نزع المعادن، في حين تمت زيادة عدد صلابة فيكرز إلى ١٨٤.٠٢ بعد فترة إعادة المعادن. وكان متوسط خط الأساس لعدد صلابة فيكرز للمجموعة ٢ هو ٥٠٦.٩١، الذي انخفض إلى ٣١٧.٦ بعد نزع المعادن، ثم ارتفع إلى ٤٣٥.١٩ بعد إعادة المعادن. كشفت قيم عدد صلابة فيكرز لكلا المجموعتين في مقارنات المجموعة المشتركة وداخل المجموعة فروق ذات دلالة إحصائية. الاستنتاجات: أظهرت دراستنا أن دهن عينات المينا بالبروبوليس ساعد في تحسين مستويات الصلابة الدقيقة، أكثر من مجموعة التحكم. الدراسات المستقبلية ضرورية للتحقق من الآلية الدقيقة للآثار المفيدة للبروبوليس على طبقة المينا. Abstract: Objective: In this in vitro study, we aimed to analyse the enamel-remineralisation potential of propolis. Materials and methods: Twenty enamel blocks (N = 20) were randomly divided into two groups (n = 10). In group 1 (control), enamel blocks were brushed with artificial saliva (AS). In group 2, they were brushed with propolis oil. All the blocks were demineralised by exposing them to 6 wt% citric acid (pH: 2.2) for 5 min. Brushing was performed inside a tooth brushing simulation machine with manual toothbrushes. Each sample received 5,000 linear strokes. Surface microhardness analysis was performed for each sample at three time intervals (pre-demineralisation or baseline, post-demineralisation, and post-remineralisation) to obtain the Vickers hardness numbers (VHNs). Results: An enhancement in the microhardness of the enamel samples was observed after brushing with propolis oil when compared with brushing using AS alone. In group 1 (control group), the mean baseline VHN was 583.66. It decreased to 116.23 after demineralisation and increased to 184.02 after remineralisation. The mean baseline VHN of group 2 was 506.91. It decreased to 317.60 after demineralisation and increased to 435.19 after remineralisation. The VHN values of both the groups revealed statistically significant differences (p

Collagen is the building block for the extracellular matrix in bone, teeth and other fibrous tissues. Osteogenesis imperfecta (OI), or brittle bone disease, is a heritable disorder that results from defective collagen synthesis or metabolism, resulting in bone fragility. The dental manifestation of OI is dentinogenesis imperfecta (DI), a genetic disorder that affects dentin structure and clinical appearance, with a characteristic feature of greyish-brown discolouration. The aim of this study was to conduct a systematic review to identify and/or define any ultrastructural changes in dentinal collagen in DI. Established databases were searched: Cochrane Library, OVID Embase, OVID Medline and PubMed/Medline. Search strategies included: Collagen Ultrastructure, DI and OI. Inclusion criteria were studies written in English, published after 1990, that examined human dental collagen of teeth affected by DI. A Cochrane data extraction form was modified and used for data collection. The final dataset included seventeen studies published from 1993 to 2021. The most prevalent findings on collagen in DI teeth were increased coarse collagen fibres and decreased fibre quantity. Additional findings included changes to fibre orientation (i.e., random to parallel) and differences to the fibre organisation (i.e., regular to irregular). Ultrastructural defects and anomalies included uncoiled collagen fibres and increased D-banding periodicity. Studies in collagen structure in DI reported changes to the surface topography, quantity, organisation and orientation of the fibres. Moreover, ultrastructural defects such as the packing/coiling and D-banding of the fibrils, as well as differences in the presence of other collagens are also noted. Taken together, this study provides an understanding of the changes in collagen and its impact on clinical translation, paving the way for innovative treatments in dental treatment.

Objective: To investigate the antibiofilm and remineralising effects of the dual-action peptide GA-KR12 on artificial enamel caries. Materials and methods: Enamel blocks with artificial caries were treated with sterilised deionised water as control or GA-KR12. The blocks underwent biochemical cycling with Streptococcus mutans for 3 weeks. The architecture, viability, and growth kinetics of the biofilm were determined, respectively, by scanning electron microscopy (SEM), confocal laser scanning microscopy, and quantitative (culture colony-forming units, CFUs). The mineral loss, calcium-to-phosphorus ratio, surface morphology, and crystal characteristics of the enamel surface were determined, respectively, using micro-computed tomography, energy dispersive spectroscopy, SEM, and X-ray diffraction (XRD). Results: SEM showed confluent growth of S. mutans in the control group but not in the GA-KR12-treated group. The dead-to-live ratios of the control and GA-KR12-treated groups were 0.42 ± 0.05 and 0.81 ± 0.08, respectively (p < 0.001). The log CFUs of the control and GA-KR12-treated groups were 8.15 ± 0.32 and 6.70 ± 0.49, respectively (p < 0.001). The mineral losses of the control and GA-KR12-treated groups were 1.39 ± 0.09 gcm−3 and 1.19 ± 0.05 gcm−3, respectively (p < 0.001). The calcium-to-phosphorus molar ratios of the control and GA-KR12-treated groups were 1.47 ± 0.03 and 1.57 ± 0.02, respectively (p < 0.001). A uniformly remineralised prismatic pattern on enamel blocks was observed in the GA-KR12-treated but not in the control group. The hydroxyapatite in the GA-KR12-treated group was better crystallised than that in the control group. Conclusion: The dual-action peptide GA-KR12 inhibited the growth of S. mutans biofilm and promoted the remineralisation of enamel caries. Clinical relevance: GA-KR12 potentially is applicable for managing enamel caries. [ABSTRACT FROM AUTHOR]

During the past decades, near-infrared (NIR) methods have been applied to many aspects of life, particularly in dentistry. X-ray methods involve reliable techniques that dentists use to evaluate tooth structure lesions. However, X-ray methods still have some limitations, such as affecting patient health and dentists. In addition, early demineralised enamel is barely detected by X-ray methods. Many studies have demonstrated the usefulness of NIR light for observing tooth structure due to the differences of the optical properties between sound and demineralised tooth tissues under NIR wavelengths. Early demineralisation located under the enamel layer can be observed by NIR imaging (780-1,300 nm). The areas suspected to be demineralised enamel are distinct from the stain and pigmentation because stain and pigmentation do not appear in NIR images. The demineralised areas are substantially darker than the surrounding sound tissues under NIR light. In this study, two optical systems with transillumination and scattering techniques using NIR light (940 nm) were built for capturing occlusal and approximal images of teeth. The systems fulfill some requirements, such as simple setup, safety, and affordable price for the purpose of the replacement of imported equipment.

Introduction: Enamel gets demineralised when they get exposed to acidic environment. Very common issue seen after orthodontic treatment is white spot lesion and also there is a chance of inflammation in periodontal fibres if the fixed lingual retainer is given to the patient. Furthermore, it enhances the plaque and calculus accumulation. So, to minimise these deleterious effects, lingual retainer is modified by surface coating with silver dioxide which shows anti-bacterial and antiadhesive properties. Aim: Assessment of anti-adherent and anti-bacterial properties of silver dioxide (AgO2) surface modified Orthodontic lingual retainer against S.mutans. Materials and Methods: This cross-sectional study will use 60 orthodontic lingual retainer specimens. The samples will be divided into four groups for testing with 15 specimens in each group. The samples will be divided into four groups: two control groups with commercially available lingual retainer will be used for assessing anti-bacterial and anti-adhesion properties and other two will be of surface treated lingual retainer for testing. Bacterial strains will be taken with sample size 15 in each group then the preparation of photocatalytic silver dioxide-coated orthodontic lingual retainer. Even coating will be ensured by sputtering technique and thickness of coating will be 50-60 nm. Chi-square test will be used to analyse differences in categorical variables. Expected outcome: The photocatalytic (AgO2) coated retainer will reduce the bacterial accumulation and adhesion. Conclusion: Surface modification of lingual retainers with photocatalytic AgO2 will reduce the bacterial adhesion which can be used to prevent the formation of dental plaque and demineralization orthodontic treatment, thereby preventing demineralization of enamel and periodontal breakdown. [ABSTRACT FROM AUTHOR]

Introduction: Recently, various modes of fluoride varnishes have evolved, each with its own recommended concentration, potentially active ingredients, and flavour, leading to a claim of additional preventive benefits. Differences in fluoride release patterns can potentially enhance or reduce the efficacy of fluoride varnishes. Numerous clinical trials have proven its ability in preventing and arresting dental caries. This study mainly focused on the investigations of the apatite demineralisation process under the effect of different fluoride varnishes by ion-selective electrodes (ISE), in an attempt to comprehend their mechanism in anti-caries. Methods: Four different fluoride varnishes (Fluor Protector S, Duraphat, ClinPro White, MI Varnish) were used to measure their effect on the demineralisation process of the hydroxyapatite (HAP) discs in 60ml pH 4.0 acetic solutions. The HAP discs were treated with these varnishes after 4-hours demineralisation and then immersed back into the same solutions for further demineralisation to observe the effect of the varnishes. Throughout the experiment, the calcium ISE was used to monitor the rate of calcium concentration. Results: The result demonstrated that ClinPro White varnish resulted in the most significant inhibition of demineralisation and signs of probable remineralisation throughout the experiment. Other fluoride varnishes treatment showed the ability to inhibit demineralisation. However, the rate of calcium dissolution was not significantly different from different varnishes. The fact that the ClinPro White showed evidence of remineralisation might be associated with the fact that the varnish contained a source of calcium and phosphate. Conclusion: The fluoride varnishes treatment is shown to be effective in inhibiting the demineralisation of apatite regardless of the difference in fluoride concentration and potentially active ingredients incorporated in some of the fluoride varnishes.

Salwa Ibrahim,1,* Adam P Strange,2,* Sebastian Aguayo,2,3 Albatool Shinawi,1 Nabilah Harith,1 Nurjehan Mohamed-Ibrahim,1 Samera Siddiqui,2 Susan Parekh,1 Laurent Bozec4 1Department of Paediatric Dentistry, UCL Eastman Dental Institute, University College London, London, UK; 2Department of Biomaterials and Tissue Engineering, UCL Eastman Dental Institute, University College London, London, UK; 3School of Dentistry, Faculty of Medicine, Pontificia Universidad Católica de Chile, Santiago, Chile; 4Faculty of Dentistry, University of Toronto, Toronto, Canada*These authors contributed equally to this workCorrespondence: Laurent BozecFaculty of Dentistry, University of Toronto, 124 Edward Street, Toronto ON M5G 1G6, CanadaEmail L.bozec@utoronto.caIntroduction: Dentinogenesis imperfecta type 1 (OIDI) is considered a relatively rare genetic disorder (1:5000 to 1:45,000) associated with osteogenesis imperfecta. OIDI impacts the formation of collagen fibrils in dentin, leading to morphological and structural changes that affect the strength and appearance of teeth. However, there is still a lack of understanding regarding the nanoscale characterization of the disease, in terms of collagen ultrastructure and mechanical properties. Therefore, this research presents a qualitative and quantitative report into the phenotype and characterization of OIDI in dentin, by using a combination of imaging, nanomechanical approaches.Methods: For this study, 8 primary molars from OIDI patients and 8 primary control molars were collected, embedded in acrylic resin and cut into longitudinal sections. Sections were then demineralized in 37% phosphoric acid using a protocol developed in-house. Initial experiments demonstrated the effectiveness of the demineralization protocol, as the ATR-FTIR spectral fingerprints showed an increase in the amide bands together with a decrease in phosphate content. Structural and mechanical analyses were performed directly on both the mineralized and demineralized samples using a combination of scanning electron microscopy, atomic force microscopy, and Wallace indentation.Results: Mesoscale imaging showed alterations in dentinal tubule morphology in OIDI patients, with a reduced number of tubules and a decreased tubule diameter compared to healthy controls. Nanoscale collagen ultrastructure presented a similar D-banding periodicity between OIDI and controls. Reduced collagen fibrils diameter was also recorded for the OIDI group. The hardness of the (mineralized) control dentin was found to be significantly higher (p

The article presents the discussion on assessing conditioning of the tooth surface with butter prior to subjecting the tooth to demineralisation. Topics include dental caries being a disease of the microbial origin where caries prevention focusing towards development of antimicrobial agents; and caries protective agent being used for either antimicrobial or focusing towards remineralisation of the carious lesion.

Introduction: Dental Caries is primarily a disease of multifactorial origin. The streptococcus mutans the causative agent adheres to the tooth surface and breaks down the sugar to produce lactic acid as the by product which brings about demineralisation of tooth structure. There is a need to identify substance which prevents adhesion of the organism to the tooth surface thereby preventing colonisation. Aim: To assess conditioning of the tooth surface with butter prior to subjecting the tooth to demineralisation. Materials and Methods: An in vitro experimental trial was conducted on 45 non carious premolars. The teeth were divided in 3 groups of 15 each. Group I received no pretreatment. The group II and III received thin and thick layer of butter coating, respectively. The teeth were then immersed in demineralising solution and the effect of the of the same was assessed using Scanning Electron Microscope (SEM). Since the data obtained was qualitative, any statistical test were not applied. The observations recorded were based on the repetition of the similar findings in more than 50% of the samples. Results: The results of the study indicated the presence of islands of protected enamel and limited destruction in the prismatic pattern on the samples with thin coating of butter. Samples with thick butter coating showed presence of intact prismatic substance in contrast to the unprotected teeth which showed loss of prismatic substance. Conclusion: Pretreatment of the tooth surface with thin coating of butter prior to exposing the tooth to cariogenic environment protects the enamel from undergoing demineralisation.

It has proven effective to recover metal compounds from aqueous mixtures by use of antisolvents; organic compounds that induce selective precipitation. A challenge with antisolvents is that they are both costly to produce and recover on an industrial scale. In recycling of lithium-ion batteries and recovering critical metals, we find that electrodialysis can be a competitive method for purifying and recycling antisolvents. In this study we investigate the use of electrodialysis to separate salt and water from a ternary solution of water, KCl and ethanol. A coupled non-equilibrium electrochemical model is developed to understand how such systems may be operated, designed, and which characteristics that are required for the ion exchange membranes. We demonstrate how the water transference coefficients of the membranes should be tuned in the process optimisation and why membrane property design is crucial to the success of this concept. Residual mixtures from antisolvent precipitation, with ethanol (EtOH) solvent weight fractions around 0.6-0.7, can be demineralised and the EtOH fraction increased by 0.1-0.2 at an energy requirement of 60-200 kWh m EtOH − 3 by use of electrodialysis. In an example application of the concept, aqueous KCl is precipitated by recycled ethanol in a cyclic process, requiring 0.161 kWh mol KCl − 1. This example case considers complete ethanol rejection by the membranes and abundant water co-transport, characterised by the transference coefficients: t w = 15 and t a = 0 for water and EtOH respectively. The findings pave the way for new applications with aqueous mixtures of critical metals. [Display omitted] • Electrodialysis for antisolvent recovery and demineralisation. • Electrodialysis process simulated with non-equilibrium thermodynamics model. • Organics-rejecting membranes allows for partial purification of antisolvent. • Ternary example mixture using ethanol, KCl and water. • Model process requires 0.161 kWh mol KCl − 1 and 73 kWh m EtOH − 3. [ABSTRACT FROM AUTHOR]

Abstract Coal still remains an important source of power generation world over. Along with its usage, comes unwanted generation of noxious gas emissions, toxic metal releases into wastewater and other pollutants which ultimately lead to environmental concerns. So cleaning of coal through physical or chemical processes becomes utmost important. There are several coals which cannot be cleaned by physical beneficiation techniques to produce low ash cleaner coals. Such coals can be cleaned only through chemical cleaning techniques. The present paper reviews the chemical demineralisation and desulphurisation of coals over the years using various inorganic and organic acids, alkalis, oxidants, leachants and various acids and alkali-acid combinations to reduce the ash and sulphur contents in coals. As high as 90% demineralisation and desulfurization could be achieved with the use of these cheap inorganic acids as compared to the expensive solvents used for solvent extraction processes, a parallel approach of cleaning and refining coals.

Fluoride is a key dentifrice ingredient for mitigating dental erosion and promoting remineralisation in tooth enamel. A dentifrice formulation (NaF/CL ‐ where C = Copolymer, L = Lactate), optimised for fluoride delivery, containing sodium fluoride, polyvinylmethylether–maleic anhydride (PVM/MA) copolymer and lactate ion at controlled pH of 6.2 is compared with six commercial dentifrices from European and US regulatory regions. The in vitro study utilised white light interferometry (WLI) and dynamic secondary ion mass spectrometry (DSIMS) to assess dental erosion resistance and remineralisation potential of the dentifrices. For WLI, polished enamel samples were immersed in dentifrice slurry (1:3 wt./wt. in artificial saliva, 2 min), brushed, washed in deionised water, acid challenged (1% citric acid, pH 3.8, 5 min), washed and air dried. Surface roughness and bulk tissue loss were measured. DSIMS samples for fluoride uptake were acid challenged (1% citric acid, pH 3.8, 5 min), rinsed, immersed in dentifrice slurry (1:3 wt./wt. in artificial saliva, 2 min), washed and air dried. DSIMS samples for 44Ca uptake were prepared similarly but with 44Ca‐doped artificial saliva. The NaF/CL dentifrice provided highest protection against dental erosion, with highest fluoride and 44Ca uptake in all treatment groups (n = 5 per group). Dentifrices containing other fluoride salts and/or ingredients known to inhibit fluoride uptake (e.g., polyphosphates, sodium lauryl sulfate), performed significantly worse. [ABSTRACT FROM AUTHOR]

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Background: The aim of the study was to compare the effect of chicken eggshell powder and gallic acid as remineralising agent on early enamel caries lesion. Material and Methods: Ten extracted deciduous molars was cleaned using distilled water. The teeth were decoronated at CEJ. Each decoronated tooth then sectioned longitudinally in a mesio-distal direction first and then in a bucco-lingual direction with diamond disc so that four samples obtained from a single tooth. Then from these samples, four enamel blocks of dimensions (4mm long, 4mm width and 2mm thick) made from each sample and embedded in acrylic blocks. These 40 samples are divided into four groups, each having 10 samples (GROUP A,B,C,D). Samples were demineralised followed by application of chicken egg shell solution and gallic acid. Chicken egg shell has the highest content of Calcium present as compared to Gallic acid.The ratio of Calcium/Phosphorous was found to be increased in the following sequence. Chicken egg shell>Gallic acid>Control>Demineralised group. Conclusion: It can be concluded from the results shows that Calcium has a vital role in remineralisation. [ABSTRACT FROM AUTHOR]

Purpose: To test the effectiveness of yogurt extract as an agent to protect tooth enamel from demineralisation in vitro. Materials and Methods: The crowns of 80 intact caries-free human premolars were selected, and standardised 5 x 3 mm² enamel windows were isolated on the buccal and lingual surface of each tooth. The baseline weight of each specimen was recorded. Four demineralising solutions were prepared: S1: lactic acid (LA) at pH 4.8; S2: LA at pH 3.97; S3: LA + yogurt supernatant (YS) at pH 4.8; S4: LA + YS at pH 3.97. The calcium content of each solution was determined using compleximetric titration with Eriochrome black-T. The 80 teeth were randomly divided into 4 groups. Each group was incubated in its corresponding solution at 37°C for 96 h. The specimens were weighed again and the calcium content of the four solutions determined. Five samples from each group were randomly chosen, sectioned through the treatment windows, stained with rhodamine-B and viewed under a confocal laser scanning microscope (CLSM). Lesion area (LeA) and average fluorescence (AF) were calculated using Image J software. Total fluorescence (TF) values were obtained by LeA x AF. Results: There was a statistically significant difference between groups in terms of LeA and TF . No statistically significant difference was found between groups in terms of difference in weight. Conclusion: Probiotic yogurt extract is effective in reducing demineralisation of enamel under experimental conditions. [ABSTRACT FROM AUTHOR]

Acid-induced enamel demineralisation affects many individuals either by exposure to acidic diets, acidic gas pollution (dental erosion) or to dental plaque acids (dental caries). This study aimed to develop in situ X-ray and light imaging methods to determine progression of enamel demineralisation and the dynamic relationship between acid pH and mineral density. Hourly digital microradiograph time-lapse sequences showed the depth of enamel demineralisation in 500 µm thick sections progressed with time from the surface towards the dentine following a power-law function, which was 21% faster than the lateral demineralisation progression after exposure for 85 h to lactic acid (10%, pH 2.2). The minimum greyscale remaining (mineral content) within the induced enamel lesion followed an exponential decay, while the accumulated total greyscale loss with time was linear, which showed a constant anisotropic mineral release within the enamel architecture. This 85 h demineralisation method studied by polarised light microscopy time-lapse sequences showed that once the demineralisation front reached the enamel Hunter-Schreger bands, there was preferential demineralisation along those bands. Mineral density loss was linear with increasing pH acidity between pH 5.2 and pH 4.0 (with 0.4 pH increments) when incubated over a 3-week period exposed to 0.5% lactic acid. At pH 4.0, there was complete mineral loss in the centre of the demineralised area after the 3-week period and the linear function intercepted the x-axis at ~ pH 5.5, near the critical pH for hydroxyapatite (HAp). These observations showed how intrinsic enamel structure and pH affected the progression of demineralisation. Hydroxyapatite crystallites (HAp) in human enamel dissolve when exposed to an acidic environment but little is known about how the intrinsic structures in enamel and pH influence the demineralisation kinetics. We have developed a time-lapse in situ microradiography method to quantify microscopic anisotropic mineral loss dynamics in response to an acid-only caries model. Correlation with polarised light microscopy time-lapse sequences showed that larger structures in enamel also influence demineralisation progression as demineralisation occurred preferentially along the Hunter-Schreger bands (decussating prismatic enamel). The pH-controlled enamel mineral release in a linear manner quantifying the relationship between HAp orientation and acid solubility. These findings should direct the development of improved anti-demineralisation/ remineralisation treatments to retain/ restore the natural intrinsic enamel structure. Image, graphical abstract [ABSTRACT FROM AUTHOR]

Introduction: Dental caries is a multifactorial microbial infectious disease characterised by demineralisation of the inorganic and destruction of the organic substance of the tooth. To combat dental caries the application of nanotechnology includes the inhibition of formation of biofilm and regulating the balance of demineralisation-remineralisation processes, ensuring a possible mechanism that can aid in prevention and treatment of tooth decay. Initial caries progression may be prevented by suitable surface treatment, by applying surface remineralising agents. Aim: To evaluate and compare the efficacy of remineralising potential of Acidulated Phosphate Fluoride (APF) gel, Chitosan nanoparticles and Silver Diamine Fluoride (SDF) on microhardness of artificial carious lesions created on extracted teeth. Materials and Methods: This was an in-vitro experimental study associated with Krishna Institute of Medical Sciences, Karad conducted during a period of two months (October and November 2019) at Mechanical Department of Rajarambapu Institute of Technology, Islampur, Maharashtra. The total sample size was 30 premolar teeth. In this in-vitro study, test materials Chitosan nanoparticles, Silver Diamine Fluoride (SDF) and Acidulated Phosphate Fluoride gel (APF) varnishes were manipulated and applied (10 in each group) in accordance with manufacturer’s instructions. Artificial carious lesions were created in the enamel. This was achieved by suspending the teeth in an artificial caries system. Baseline microhardness was then recorded using Vickers Hardness Test and varnish application was carried out. Samples were then placed separately in a demineralisation solution for three hours. Thereafter, samples were placed in a remineralisation solution. Any change in microhardness was determined by evaluating the Vickers Hardness Test at the end of 28 days. The data was then recorded, tabulated and statistically analysed using KruskalWallis Test and Wilcoxon Signed Test for inter and intra groups comparisons to find out if there was a significant difference. Results: All the three varnishes i.e., Chitosan nanoparticle, silver diamine fluoride and APF gel in intragroup comparison after intervention showed significant differences with Chitosan nanoparticle showing the highest increase in microhardness with p-value of 0.001 followed by SDF with p-value of 0.005 and APF gel with p-value of 0.005. Conclusion: All the three varnishes increased enamel microhardness significantly. Chitosan nanoparticle showed highest increase in remineralisation followed by SDF and APF gel. Hence, varnish application is a good method in remineralising the tooth.

The biochemical definition of dental caries is reasonably understood and generally agreed upon, but there is no consensus on a clinical definition among dentists. There are many proposed diagnostic criteria of dental caries in the dental literature. The recently developed International Caries Detection and Assessment System (ICDAS II) has been constructed to allow data comparison between studies. It can be used in epidemiological studies, public health research, clinical research, clinical practice and dental education. A good study evaluating a caries detection method should contain information on caries prevalence of the study sample and other measures, including sensitivity, specificity, positive predictive value (PPV) and negative predictive value (NPV). It is noteworthy that measuring sensitivity and specificity provides no quantitative information on how likely a tested tooth is to be carious because the true caries status of the tooth is not known in a clinical situation. Moreover, the study design for caries detection should address the interpretation of predictive values because PPV and NPV are affected by the caries prevalence. The study design should also measure patient-oriented outcomes, address allocation concealment and avoid lead-time bias to generate valid and clinically relevant studies. Prudent evaluation of caries detection methods is the standard of care. This paper reviews current diagnostic criteria for caries detection and discusses proper ways to evaluate new diagnostic methods. [ABSTRACT FROM AUTHOR]

In vitro simulation of natural caries is of great importance in dental research for the development of more effective clinical treatments. The pH-cycling (pHc) procedure consists of a dynamic caries process with alternating de-remineralisation periods. The current research aims to evaluate the effects of the pHc procedure on mineral dentine properties in comparison with sound dentine and natural residual caries. For this purpose, dentine slices from human third molars were submitted to cycling periods of 14 and 28 days. The chemical composition, morphological and microstructural properties of the dentine samples were examined by infrared and Raman spectroscopies, X-ray diffraction, and scanning electron microscopy techniques. In addition, the depth of the demineralisation front was evaluated by Masson’s trichrome (MT) staining. The results showed that the pHc procedure led to notable changes in the mineral composition and the crystalline characteristics with respect to sound dentine and some extent to natural caries. The MT results revealed that pHc 28 yields a deeper lesion than pHc 14, simulating potential progression of natural caries. The results of this study provide a better understanding of the mechanisms of demineralisation that could occur in an in vivo environment and provide a standardised substrate similar to natural residual caries.

Introduction: Dental caries is a multifactorial microbial infectious disease characterised by demineralisation of the inorganic and destruction of the organic substance of the tooth. To combat dental caries the application of nanotechnology includes the inhibition of formation of biofilm and regulating the balance of demineralisation-remineralisation processes, ensuring a possible mechanism that can aid in prevention and treatment of tooth decay. Initial caries progression may be prevented by suitable surface treatment, by applying surface remineralising agents. Aim: To evaluate and compare the efficacy of remineralising potential of Acidulated Phosphate Fluoride (APF) gel, Chitosan nanoparticles and Silver Diamine Fluoride (SDF) on microhardness of artificial carious lesions created on extracted teeth. Materials and Methods: This was an in-vitro experimental study associated with Krishna Institute of Medical Sciences, Karad conducted during a period of two months (October and November 2019) at Mechanical Department of Rajarambapu Institute of Technology, Islampur, Maharashtra. The total sample size was 30 premolar teeth. In this in-vitro study, test materials Chitosan nanoparticles, Silver Diamine Fluoride (SDF) and Acidulated Phosphate Fluoride gel (APF) varnishes were manipulated and applied (10 in each group) in accordance with manufacturer’s instructions. Artificial carious lesions were created in the enamel. This was achieved by suspending the teeth in an artificial caries system. Baseline microhardness was then recorded using Vickers Hardness Test and varnish application was carried out. Samples were then placed separately in a demineralisation solution for three hours. Thereafter, samples were placed in a remineralisation solution. Any change in microhardness was determined by evaluating the Vickers Hardness Test at the end of 28 days. The data was then recorded, tabulated and statistically analysed using KruskalWallis Test and Wilcoxon Signed Test for inter and intra groups comparisons to find out if there was a significant difference. Results: All the three varnishes i.e., Chitosan nanoparticle, silver diamine fluoride and APF gel in intragroup comparison after intervention showed significant differences with Chitosan nanoparticle showing the highest increase in microhardness with p-value of 0.001 followed by SDF with p-value of 0.005 and APF gel with p-value of 0.005. Conclusion: All the three varnishes increased enamel microhardness significantly. Chitosan nanoparticle showed highest increase in remineralisation followed by SDF and APF gel. Hence, varnish application is a good method in remineralising the tooth. [ABSTRACT FROM AUTHOR]

Genetic characterisation of wild ungulates can be a useful tool in wildlife management and in obtaining a greater understanding of their biological and ecological roles in a wider spatiotemporal context. Different ways of optimising methodologies and reducing the costs of genetic analyses using widely available bone tissues collected within regular hunting allocations were examined. Successful isolation and analysis of DNA from widely available bones can be cheap, fast and easy. In particular, this study explored the possibility of using bones for extracting high quality nuclear DNA for microsatellite analysis. The utility of applying a modified demineralisation process using two commercially available DNA isolation kits, which differ significantly in price, was evaluated. The sample sets included bones and, for comparison, muscle tissues from four wild ungulate species: chamois (Rupicapra rupicapra), roe deer (Capreolus capreolus), wild boar (Sus scrofa), and Alpine ibex (Capra ibex). For the recent bones, these results confirmed that the DNA concentrations and microsatellite amplification were sufficiently high, even when using low-cost kits, after prior demineralisation. For old bones, prior demineralisation and use of a specially designed isolation kit led to a more successful extraction of DNA. Besides reducing kit-related costs, low-cost kits are much faster and therefore make genetic analysis more efficient. [ABSTRACT FROM AUTHOR]

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Aim: This study quantitatively investigated the changes in enamel mineral content of primary teeth after immersion in human breast milk and plain and probiotic-containing infant formulas. Methods: Thirty-six sound primary anterior teeth were collected and assessed for mineral content (calcium and phosphorus content in wt%) using scanning electron microscope attached with energy-dispersive X-ray analyser (SEM–EDXA). In order to create a microbial-induced caries model, the enamel surfaces of the teeth were inoculated with mutans streptococci and then each tooth was randomly assigned to one of three groups: human breast milk, plain infant formula or probiotic-containing infant formula (n = 12) each. Teeth were then soaked in the designated type of milk, and the solutions were replenished every day for 1 week after which the mineral content was measured again using SEM–EDXA. Wilcoxon signed-rank test was used to study the changes by time within each group, and the significance level was set at P ≤ 0.05. Results: Treatment of enamel surface with breast milk has significantly increased mean Ca wt%, while no significant changes were detected in mean P wt%. On the other hand, when primary teeth were soaked in plain or probiotic-containing infant formulas, both mean values of both Ca and P wt% significantly decreased. Conclusions: In conclusion, whereas breast milk might confer some protective effect against enamel demineralisation, infant formulas whether plain or supplemented with some probiotics might promote loss of minerals from enamel surface. [ABSTRACT FROM AUTHOR]

Calcium contents of demineralised human cortical bone determined by titrimetric assay and atomic absorption spectrophotometry technique were verified by comparing to neutron activation analysis which has high recovery of more than 90%. Conversion factors determined from the comparison is necessary to correct the calcium content for each technique. Femurs from cadaveric donors were cut into cortical rings and demineralised in 0.5 M hydrochloric acid for varying immersion times. Initial calcium content in the cortical bone measured by titration was 4.57%, only 21% of the measurement by neutron activation analysis; while measured by atomic absorption spectrophotometer was 13.4%, only 61% of neutron activation analysis. By comparing more readings with the measurements by neutron activation analysis with 93% recovery, a conversion factor of 4.83 was verified and applied for the readings by titration and 1.45 for atomic absorption spectrophotometer in calculating the correct calcium contents. The residual calcium content started to reduce after the cortical bone was demineralised in hydrochloric acid for 8 h and reduced to 13% after 24 h. Using the linear relationship, the residual calcium content could be reduced to less than 8% after immersion in hydrochloric acid for 40 h. Atomic absorption spectrophotometry technique is the method of choice for calcium content determination as it is more reliable compared to titrimetric assay. [ABSTRACT FROM AUTHOR]

Objective: To evaluate root dentine demineralisation, biomass and loosely bound fluoride (CaF2 ) concentration according to different frequencies of sucrose exposure using a high-fluoride dentifrice.Background: Although high-fluoride dentifrice has been recommended to arrest root dentine lesions, it is not clear whether it can protect dentine from increased frequencies of sucrose exposure.Methods: An in situ, crossover, split-mouth study was conducted in 3 phases with 7 days each, in which 10 volunteers used a palatal device containing 4 bovine root dentine slabs (2 on each side) with predetermined initial hardness. Cariogenic challenge consisted in dripping a 20% sucrose solution 0 (control), 2, 4, 6, 8 or 10 times/d in each block. Volunteers used high-fluoride dentifrice (NaF, 5000 µg F/g) 3 times/d. After each phase, final hardness was measured and the percentage of surface hardness loss (%SHL) calculated. Also, biomass and CaF2 concentration on dentine were determined. The data were processed and analysed by ANOVA and Tukey test with significance level set at 5%. The relationship between the variables was analysed by linear regression and Pearson correlation (r).Results: %SHL and biomass were significantly greater than control for sucrose frequencies higher than 6 times/d (P < 0.001), while CaF2 concentration decreased from sucrose frequency higher than 2 times/d (P < 0.001). Regression analysis data showed a significant linear fit between sucrose exposure frequency and the studied variables with a strong correlation (r) for %SHL and CaF2 and moderate for biomass (P < 0.05).Conclusion: High-fluoride dentifrice is able to reduce root dentine demineralisation if sucrose consumption is not higher than 6 times/d. [ABSTRACT FROM AUTHOR]

Purpose: To evaluate the effect of CO2 laser treatment through topically applied amine fluoride solution on demineralised enamel.Materials and Methods: Sixty extracted human molar crowns were selected and cut longitudinally into half. One half was subjected to a 10-day pH-cycling procedure to create caries-like lesions, whereas the other was left non-demineralised. The following treatments were randomly assigned (one treatment per tooth, on respective non-demineralised and demineralised matched specimens): exposure to a 1% amine fluoride solution for 15 s without irradiation (group I), irradiation for 15 s with a continuous-wave CO2 laser (group II), or laser-treatment for 15 s through the amine fluoride solution applied immediately beforehand (group III). Fluoride uptake (n = 30) and acid resistance (n = 30) were determined after treatment. Enamel surface alterations after laser irradiation were monitored using scanning electron microscopy.Results: In groups I and III, an increased fluoride uptake was detected (p < or = 0.05). Laser irradiation through topical fluoride resulted in an increased acid resistance of sound and demineralised enamel specimens in deeper layers (p < or = 0.05). In addition, less surface alterations were observed in SEM examination of specimens irradiated through the amine fluoride solution compared with counterparts treated with laser only.Conclusions: CO2 laser light application through an amine fluoride solution may be instrumental in enhancing acid resistance of sound and demineralised enamel. [ABSTRACT FROM AUTHOR]

One of the modern directions of mussel shells utilisation is associated with the production of mineral-free biomaterials that can be successfully used in food production, feed additives production, in biotechnologies, as well as in biomedicine. The objectives of this study are to obtain an organic matrix (conchix) from mussel (Mytilus edulis L.) shells by demineralisation using two decalcifying agents—a solution of hydrochloric acid (HCl) and a solution of disodium salt of ethylenediaminetetraacetic acid (Na 2 -EDTA), as well as the influence of the decalcifying agent nature on the organic matrix structure. The degree of demineralisation of the obtained conchixes when using HCl reaches 100%. It has been shown that the native structure of the organic matrix proteins is partially destroyed during the demineralisation of the shells in the HCl solution; analysis of IR spectra indicates a 1.5-fold decrease in the number of α-helices compared to the organic matrix obtained by gentle Na 2 -EDTA-based demineralisation. SEM and TEM studies indicate the destruction of the biopolymer structure of the outer (periostracum) and inner (prismatic and nacreous) layers of the organic matrix obtained using HCl, while this structure is completely preserved when using Na 2 -EDTA. The results obtained indicate the preference of using Na 2 -EDTA for the production of biomaterials with potential use in food technology and biomedicine. • Mineral-free biomaterial (conchix) is a product of demineralisation of mussel shells. • HCl and N 2 -EDTA solutions are used as demineralising agents for isolating conchix. • Gentle N 2 -EDTA-based method does not destroy the protein secondary structure. • Gentle decalcification preserves the biopolymer structure of the organic matrix. [ABSTRACT FROM AUTHOR]