Remineralization potential of dentifrices with calcium sodium phosphosilicate and functionalized tri-calcium phosphate in the deeper incipient carious lesions: An in vitro study.

OBJECTIVES: This study evaluated the remineralization potential of calcium sodium phosphosilicate and functionalized tri-calcium phosphate (f-TCP) dentifrices in deeper incipient carious lesions (ICLs). MATERIALS AND METHODS: Artificial ICLs were created by placing premolars into demineralizing solutions. Teeth were randomly assigned into four groups: calcium sodium phosphosilicate (Group 1), f-TCP (Group 2), 1450 ppm fluoride (Group 3), and distilled water (Group 4), which were subjected to 10-day pH cycling. Mineral density (MD) was assessed using microcomputed tomography (Micro-CT), while hardness (H) and elastic modulus (EM) were assessed using nanomechanical testing. RESULTS: MD % gain was higher in Groups 1-3 than in Group 4. In addition, Groups 1 and 2 exhibited significantly higher MD % gain than Group 3. Also, Groups 1-3 showed significantly higher EM and H values than Group 4 in the outer enamel area; yet, Groups 1 and 2 displayed significantly higher EM and H values than Groups 3 and 4 in the inner enamel. CONCLUSIONS: The MD, EM, and H of ICLs significantly increased with the addition of calcium sodium phosphosilicate or f-TCP to fluoridated dentifrices compared to standard fluoride dentifrices. The added active ingredients remineralized the deeper parts of the ICLs, while remineralization at the lesion surface was similar between tested dentifrices.

Remineralizing effects of hydroxypropyl methylcellulose film-loaded amorphous calcium phosphate nanoprecursors on enamel artificial caries lesions.

OBJECTIVES: This study was to investigate hydroxypropyl methylcellulose (HPMC) film as a carrier for amorphous fluorinated calcium phosphate (AFCP) nanoprecursors to continuously deliver biomimetic remineralization of enamel artificial caries lesions (ACL). MATERIALS AND METHODS: The AFCP/HPMC films were comprised of 25 wt% AFCP nanoparticles and 75 wt% HPMC. They were characterized by transmission electron microscopy (TEM), Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), and biocompatibility tests. Forty enamel ACL were prepared and randomly divided into four groups (n = 10): The enamel surfaces were covered with a pure HPMC film, Tooth Mousse Plus (contains 10% CPP-ACP and 0.2% NaF), and AFCP/HPMC film, or without any things (serving as negative control). Subsequently, all samples were alternatively kept in artificial saliva and a modified pH-cycling before they were characterized by Micro-CT, scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDX), attenuated total reflectance (ATR)-FTIR, XRD, and nanoindentation. RESULTS: After the enamel ACL was challenged by pH cycling, Tooth Mousse Plus and AFCP/HPMC film groups exhibited less lesion depth and mineral loss than the negative control and pure HPMC film groups. Additionally, the AFCP/HPMC film group revealed a highest remineralization rate of 55.34 ± 3.10 % among the all groups (p < 0.001). The SEM findings showed that the enamel ACL were densely deposited with minerals in the AFCP/HPMC film group, and the EDX results suggested a higher content of fluorine in the remineralized tissues. In particular, the AFCP/HPMC film group exhibited the best nanomechanical performance after 2 weeks of pH cycling (p < 0.05), with the hardness (H) restored from 0.29 ± 0.19 to 2.69 ± 0.70 GPa, and elastic modulus (Er) restored from 10.77 ± 5.30 to 68.83 ± 12.72 GPa. CONCLUSION: The AFCP/HPMC film might be used as a promising strategy for arresting or reversing incipient enamel caries lesions.

Visualization of etching cycles efficacy at the resin infiltration into artificial enamel caries: in-vitro study on bovine teeth.

This study evaluated the effect of repeated etching cycles on resin infiltrant penetration. Enamel samples measuring 4 × 4 × 3 mm3 were obtained from the facial aspect of 50 extracted bovine teeth. Samples were immersed in a demineralization solution for 21 days to create artificial lesions and divided into five equal groups (n = 10). A 15% hydrochloric acid gel was administered to each group. The acid etching application time differed between groups: Group 1; 2 min, Group 2; 2 × 2 min, Group 3; 3 × 2 min, Group 4; 4 × 2 min, and Group 5; 5 × 2 min. Resin infiltration was visualized using a confocal laser scanning microscopy. The lesion, penetration and erosion depth (µm) were calculated, and data were statistically analyzed. The highest penetration depth (75.59 ± 9.42 µm) was seen in Group 5, followed by Groups 4, 3, 2 and 1. However, there were no statistically significant differences in the penetration depths between Groups 4 and 5 and between Groups 2, 3 and 4 (p > 0.05). In conclusion, a repeated etching cycle enhanced resin infiltrant penetration.

Remineralization effects of enamel binding peptide, WGNYAYK, on enamel subsurface demineralization in vitro. Enamel binding peptide, WGNYAYK effect remineralization of enamel.

Objectives: We investigated remineralization effects of enamel binding peptide (EBP), WGNYAYK, on enamel subsurface demineralization in vitro.Methods: Bovine lower incisor crowns were used as subsurface enamel demineralization samples, and changes of EBP binding, remineraliztion rate, hardness and microstructure were investigated. Binding of EBP, remineralization rate, hardness and structural changes were investigated. Fluorescein isothiocyatate (FITC)-labeled EBPs (0.4 mM, 4.0 mM, and 7.0 mM) were applied to the samples for 30 min at 37 °C, with sample surfaces and cross-sections observed by confocal laser scanning microscope (CLSM). Mineralization analysis samples were divided into 4 experimental groups; distilled water (DW), EBP 0.4 mM, EBP 4.0 mM, and EBP 7.0 mM. Mineral density changes were measured by micro-CT with hardness measured by nano-indentation. Samples were also observed by scanning electron microscope (SEM) for surface and longitudinal microstructure. Results: CLSM images indicated that increased fluorescence was observed in the surface layer and up to about 20 µm below the surface layer. The remineralization rate was significantly higher for EBP 7.0 mM compared to DW (p = 0.008). Enamel surface hardness was significantly higher in all EBP groups compared to DW (p < 0.05) and was highest in the 7.0 mM group. SEM images showed obscuring of the superficial columnar structure in the 7.0 mM EBP group, indicating subsurface crystalline structure recovery. Conclusion: The results of this study suggest that EBP binds to demineralized enamel and promotes remineralization.

Encapsulation of a novel peptide derived from histatin-1 in liposomes against initial enamel caries in vitro and in vivo.

OBJECTIVES: Biomimetic mineralization mediated by proteins and peptides is a promising strategy for enamel repair, and its specific application model needs more research. In this work, we exploited a liposomal delivery system for a novel peptide (DK5) derived from histatin-1 (DK5-Lips) as a new biomimetic mineralization strategy against initial enamel caries. MATERIALS AND METHODS: The DK5-Lips was prepared using calcium acetate gradient method and then the in vitro release, salivary stability, and cytotoxicity were studied. Initial enamel caries was created in bovine enamel blocks and subjected to pH-cycling model treated with DK5-Lips. Surface microhardness testing, polarized light microscopy (PLM), and transverse microradiography (TMR) were analyzed. Then the biocompatibility of DK5-Lips was evaluated in the caries model of Sprague-Dawley rats, and the anti-caries effect was assessed using Micro-CT analysis, Keyes scores, and PLM in vivo. RESULTS: DK5-Lips provided a mean particle size of (97.63 ± 4.94)nm and encapsulation efficiency of (61.46 ± 1.44)%, exhibiting a sustained release profile, excellent stability in saliva, and no significant toxicity on human gingival fibroblasts (HGFs). The DK5-Lips group had higher surface microhardness recovery, shallower caries depth, and less mineral loss in bovine enamel. Animal experiments showed higher volume and density values of residual molar enamel, lower Keyes score, and shallower lesion depth of the DK5-Lips group with good biocompatibility. CONCLUSION: As a safe and effective application model, DK5-Lips could significantly promote the remineralization of initial enamel caries both in vitro and in vivo. CLINICAL RELEVANCE: The potential of liposome utilization as vehicle for oral delivery of functional peptides may provide a new way for enamel restoration.

Silver diamine fluoride with sodium fluoride varnish versus silver diamine fluoride in arresting early childhood caries: a 6-months follow up of a randomized field trial.

BACKGROUND: Early childhood caries (ECC) is the most prevalent chronic health problem in young children, and it can be arrested using professionally applied fluoride such as Sodium fluoride (NaF) varnish and Silver Diamine Fluoride (SDF). This trial compared two interventions to arrest ECC lesions: 38% SDF combined with 5% NaF varnish versus 38% SDF and assessed whether the arrest rate was affected by baseline lesion severity measured by ICDAS. METHODS: Children aged ≤ 4 years from 4 nurseries in a rural area in Alexandria, Egypt joined the study in March 2022. They were included if they had at least one active carious lesion with ICDAS codes ≥ 3. They were randomized to receive either 38% SDF with 5% NaF varnish or 38% SDF alone. In both groups, the agents were applied at baseline and after 6 months on the caries lesions. NaF was additionally applied on all teeth in the oral cavity, and it was also applied after three months. The primary outcome was lesion arrest status after six months. Parents' satisfaction with their children's appearance was the secondary outcome. Pearson Chi-Square test was used for bivariate comparison and multi-level multiple logistic regression was used to assess the effect of the intervention on caries arrest controlling for confounders. The interaction between the intervention and baseline lesion severity (categorized into moderate and severe lesions) was assessed and the p value was calculated. RESULTS: The study included 1606 lesions in 220 children, median (IQR) age = 48(9) months. The percentages of arrested lesions after the application of SDF + NaF and SDF only were 77.7% and 73.2% (p = 0.035). In multivariable analysis, SDF + NaF had significantly greater caries arrest effect than SDF alone (AOR = 2.12, p = 0.03) with significant difference (p = 0.03) between moderate (AOR = 4.10, p = 0.005) and advanced (AOR = 1.92, p = 0.08) lesions. Most parents were satisfied with their children's appearance with no significant difference between groups (SDF + NaF = 84.5%, SDF = 78.18%, p = 0.23). CONCLUSION: SDF + NaF had a higher arrest rate than SDF alone and this difference was significant in moderate but not advanced lesions. The findings have implications for the non-invasive management of ECC. TRIAL REGISTRATION: This trial was registered in the clinicaltrials.gov registry (#NCT05642494).

[The results of the study of the focus of initial caries of human tooth enamel in vitro using atomic force microscopy]. / Rezul'taty issledovaniya ochaga nachal'nogo kariesa emali zuba cheloveka in vitro s pomoshch'yu atomno-silovoi mikroskopii.

OBJECTIVE: Identify structural disorders of the surface of the enamel of a human tooth during the development of the carious process in the «white spot¼ stage using atomic force microscopy (AFM). MATERIAL AND METODS: The studies were carried out on 10 molar samples in areas with initial caries in the white spot stage. 6 areas of initial caries were scanned using the atomic force microscope Cetus Light (Nano Scan Technology, Russia) in semi-contact mode. Criteria were proposed for comparing the results of AFM scanning of tooth enamel surface samples and, based on them, the nature of the main structural disorders of the enamel surface in the affected area was determined. RESULTS: For all the samples studied, the healthy enamel surface was smoother compared to the enamel in the area of the clinically visible «white spot¼ and in the immediate vicinity of it. The heterogeneity of the enamel surface in the center of the white spot¼ for all the samples studied was at least 60% higher than at the edge of the process. It was revealed that the heterogeneity of the surface outside the clinically visible white spot at a distance of less than 1 mm from its perimeter is at least 30% higher than that of healthy tissue of the same tooth. It is shown that the heterogeneity of the enamel surface in the center of the caries area in the white spot stage is at least 4 times greater than the heterogeneity of the surface of the healthy enamel of the same tooth, which indicates its demineralization. CONCLUSION: The established features of the spread of the initial carious process can be used in clinical practice for the diagnosis and dynamic observation of the processes of enamel demineralization.

A Comparison of the Enamel Remineralisation Potential of Self-Assembling Peptides.

BACKGROUND: The aim of this research was to compare the efficacy of the remineralising potential of self-assembling peptides (SAPs): Curodont Repair (P11-4), P26, and leucine-rich amelogenin peptides (LRAP) with the standard 5% NaF varnish (Duraphat) on early enamel caries lesions (EECLs). METHODS: A demineralising solution (DS) was used to create artificial EECLs in human dental enamel specimens, which were randomly allocated to treatment groups: P11-4; P26 solution; LRAP solution; 5% NaF varnish; and deionised water (DIW). Each specimen was subjected to 8 days of pH cycling. Specimens from each test group were subjected to microcomputed tomography (micro-CT) and nanomechanical testing to assess mineral density (MD), hardness (H), and elastic modulus (EM) properties of sound, demineralised, and treated enamel. RESULTS: The mean MD percentage gain was highest in the P26 and P11-4 groups, followed by the LRAP, 5% NaF varnish, and DIW groups. There were statistically significant differences amongst groups. In the outer layer of EECLs, the EM and H were highest in P26 and P11-4 groups, followed by the LRAP and 5% NaF varnish. In the inner layer of EECLs, the EM and H were highest in P11-4 and P26 groups, indicative of enhanced penetration and remineralisation of the deeper parts of the artificial EECLs. CONCLUSIONS: P26 and P11-4 SAPs are more effective than 5% NaF varnish in remineralising the depth of EECLs.

The effectiveness of topical fluoride agents on preventing development of approximal caries in primary teeth: a randomized clinical trial.

BACKGROUND: This 18-month randomized clinical trial aimed to compare the effectiveness of two topical fluoride applications versus placebo control on preventing development of approximal caries in primary teeth. METHODS: Preschool children were recruited if they had at least one initial approximal carious lesion at the distal surface of the canines, both approximal surfaces of the first molars, or the mesial surface of the second molars assessed from bitewing radiographs. The participants were randomly allocated into 3 intervention groups: Group 1 (placebo control), Group 2 (5% sodium fluoride [NaF] varnish), and Group 3 (38% silver diamine fluoride [SDF]). All agents were applied semiannually. Two calibrated examiners evaluated the caries development from bitewing radiographs. Caries development was recorded when the baseline sound surface or initial approximal carious lesion surface developed dentin caries (beyond the outer one-third of dentine) at the follow-up examination. The intention-to-treat approach was adopted. The Chi-square test was used to analyze the effectiveness of topical fluoride agents in preventing approximal caries development and the effect of other variables. The multi-level logistic regression analysis was performed to assess the relative effectiveness of topical fluoride agents in preventing approximal caries development at the 18-month follow-up. RESULTS: At baseline, 190 participants with 2,685 sound or initial carries at the approximal surfaces were recruited. No differences in participant demographic backgrounds, oral health related habits, or caries experience were observed among the 3 groups (P > 0.05). After 18 months, 155 (82%) participants remained in the study. The rates of developing approximal caries in Groups 1, 2, and 3 were 24.1%, 17.1%, and 27.2%, respectively (P < 0.001, χ2 test). After adjusting for confounding factors and clustering effect, the multilevel logistic regression analysis showed no differences in caries development rates between the 3 groups (P > 0.05). Tooth type and the extent of a carious lesion at baseline were the significant factors for caries development. CONCLUSION: At 18-month follow-up, after adjusting for confounding factors and clustering effect, there were no statistically significant differences in preventing of approximal caries development between the semiannual application of 5%NaF, 38%SDF, or placebo. TRIAL REGISTRATION: The study was registered in the Thai Clinical Trials Registry under the number TCTR20190315003 on 15/03/2019.

Organic volume and permeability variations in the surface layer of artificial and natural enamel carious lesions.

OBJECTIVES: Test the hypothesis the type of enamel caries (natural, artificial induced by gel, and artificial induced by acid solutions) affect the organic volume and the permeability of the surface layer in enamel caries lesions. DESIGN: Artificial enamel caries, induced by either acidic solution (organic-poor; Group 1) or acidic gel (organic-rich; Group 2), and natural non-cavitated inactive approximal enamel caries lesions (NEC; Group 3) were obtained, from which longitudinal ground sections were prepared. Measurements of the mineral (Vmin) (by microradiography), and water (α) and organic (ß) volumes (by optical birefringence) were obtained at three points in the surface layer (n = 30/group). RESULTS: The main outcomes were the ratio between experimental ß by predicted ß (ß Ratio) and the ratio between experimental and predicted permeabilities (αd Ratio). ß Ratio in Group 1 was lower than in Groups 2 (Cohen's d: -1.81; 95% CI:-1.45,-2.32; p < 0.001) and 3 (Cohen's d: -0.71; 95% CI:-0.27,-1.18; p = 0.004), and Group 2 surpassed Group 3 (Cohen's d: 0.49; 95% CI:0.07,0.94; p = 0.03). αd Ratio in Group 1 was higher than in Groups 2 (Cohen's d: 1.86; 95% CI:1.49,2.33; p < 0.001) and 3 (Cohen's d: 0.60; 95% CI:0.18,1.14; p = 0.01), and Group 3 surpassed Group 2 (Cohen's d: 0.61; 95% CI:0.23,1.07; p = 0.01). CONCLUSIONS: The highest organic volume and the lowest permeability occurred at the surface layer of gel-induced artificial enamel caries lesions, which should be preferred in in vitro studies on de- and remineralization and resin infiltration.

[The evaluation of the efficiency of therapeutic and preventive measures in children aged 10-12 years with different degrees of caries intensity and the level of enamel resistance]. / Otsenka effektivnosti lechebno-profilakticheskikh meropriyatii u detei 10­12 let s raznoi stepen'yu intensivnosti kariesa i urovnem rezistentnosti emali.

THE AIM OF THE STUDY: Was to evaluate the effectiveness of therapeutic and preventive measures for children aged 10-12 years with varying degrees of caries intensity and enamel resistance. MATERIAL AND METHODS: The study comprised 308 children. We used the WHO technique (DMFT) for examining children, a hardware method for detecting foci of enamel demineralization, which were recorded using the ICDAS II system. The level of enamel resistance was determined using the enamel resistance test. Three groups of children were formed depending on the intensity of caries: group 1 - DMFT = 0 (100 people); group 2 - DMFT =1-2 (104 people); group 3 - DMFT ≥3 (104 people). Each of the groups was divided into 4 subgroups depending on the use of therapeutic and prophylactic agents. RESULTS: After carrying out therapeutic and preventive measures for 12 months, it was possible to reduce the number of foci of enamel demineralization by 23.26% and avoid the formation of new carious cavities. CONCLUSION: The planning of therapeutic and preventive measures should be personalized depending on the degree of intensity of caries and the level of resistance of tooth enamel.

Recombinant amelogenin peptide TRAP promoting remineralization of early enamel caries: An in vitro study.

Objective: To explore the regulatory effect of recombinant amelogenin peptide TRAP on the remineralization of early enamel carious lesions. Methods: Forty-eight bovine enamel blocks that prepared initial lesions in vitro were split at random into four groups for immersion treatment for 12 days: 1) remineralizing medium; 2) studied peptide 1 (consisting of the N- and C-termini of porcine amelogenin) + remineralizing medium; 3) studied peptide 2 (TRAP) + remineralizing medium; 4) fluoride + remineralizing medium. After demineralization and remineralization immersion, each specimen's mean mineral loss and lesion depth were measured using micro-computed tomography (micro-CT). The changes in lesion depth (∆LD) and mineral gain (∆Z) were computed following remineralization. The enamel samples were then cut into sections and examined with polarized light microscopy (PLM). The cross-section morphology was observed by scanning electron microscopy (SEM). The crystal phase was analyzed by an X-ray micro-diffractometer (XRD). The calcium-binding properties were determined using isothermal titration calorimetry (ITC). Results: Micro-CT analysis revealed a significant reduction in mineral loss in the four groups following the remineralization treatment (p < 0.05). The treatment with fluoride resulted in the greatest ∆Z and ∆LD, whereas the treatment with a remineralizing medium showed the least ∆Z and ∆LD among all groups. The ∆Z and ∆LD of the studied peptide 1 and studied peptide 2 groups were greater than those of the remineralizing medium group. However, there was no significant difference between the studied peptide 1 and studied peptide 2 groups (p > 0.05). All of the samples that the PLM analyzed had a thickening of the surface layer. A negative birefringent band changed in the lesion's body. The SEM displayed that minerals were formed in all four groups of samples. The XRD results indicated that the products of remineralization of the studied peptide were hydroxyapatite crystals (HA). ITC showed that there were two binding modes between the calcium and peptide TRAP. Conclusion: This study confirmed the potential of the recombinant amelogenin peptide TRAP as a key functional motif of amelogenin protein for enamel remineralization and provided a promising biomaterial for remineralization in initial enamel carious lesion treatment.

Dental caries in a Norwegian adult population, the HUNT4 oral health study; prevalence, distribution and 45-year trends.

OBJECTIVE: To investigate dental caries prevalence amongst adults in Central Norway and assess changes over the last 45 years. MATERIALS AND METHODS: The cross-sectional HUNT4 Oral Health Study was conducted in 2017-2019. A random sample of 4913 participants aged ≥19 years answered questionnaires and underwent clinical and radiographic examinations. Data were compared to findings from previous studies in the same region conducted from 1973 to 2006. RESULTS: Mean number of decayed, missing and filled teeth (D3-5MFT) was 14.9 (95% CI 14.7, 15.1), 56% of adults had one or more carious teeth (D3-5T) and 11.8% had ≥4 D3-5T, with the mean number of 1.4 (95% CI 1.32, 1.42). For initial caries, mean D1-2S was 3.8 (95% CI 3.7, 3.9), being the highest for 19-24-year-olds at 8.6 (95% CI 7.9, 9.3). Comparisons with earlier studies showed a decline in mean D3-5MFT for 35-44-year-olds from 26.5 in 1973 to 10.8 in 2019. In 1973, 4.8% of 35-44-year-olds were edentulous, while in present study edentulousness was found only in individuals >65 years. CONCLUSIONS: Despite a substantial reduction in caries experience over the last 45 years, untreated dentine caries was common, evenly distributed across all age groups. Initial caries particularly affected younger individuals, indicating a need to evaluate prevention strategies and access to dental services.

Effects of silver diamine fluoride on demineralization protection after a secondary acid challenge

Abstract Objective This investigation describes the effects of 5% sodium fluoride varnish and 38% silver diamine fluoride on demineralization protection of human enamel lesions of three different severities after a secondary acid challenge. Study design Specimens underwent color and enamel surface microhardness change measurements after demineralization and treatment events. Transverse microradiography was conducted following the secondary demineralization. Results After treatments, enamel surface microhardness change showed that 24-hour lesions treated with fluoride varnish had less rehardening than 24-hour lesions treated with silver diamine fluoride (p<0.05), whereas 144-hour lesions from both treatment groups showed a beneficial decrease in surface microhardness change that was markedly better in samples treated with silver diamine fluoride (p<0.05). After the secondary demineralization, 24- and 144-hour lesions treated with silver diamine fluoride showed a sustained beneficial decrease in enamel surface microhardness change when compared to fluoride varnish-treated samples of the corresponding lesion severity (p<0.05). Transverse microradiography showed no difference between fluoride varnish- and silver diamine fluoride-treated samples of any corresponding lesion severity, indicating that remineralization in both fluoride varnish- and silver diamine fluoride-treated samples was proportional to each other after a secondary acid challenge. Conclusions Using silver diamine fluoride may have comparable benefits to fluoride varnish in mineral loss prevention.

Dental Students' Ability to Detect Only-Enamel Proximal Caries on Bitewing Radiographs.

Introduction The dental students are trained to identify the proximal carious lesion using clinical tools and radiography over three years of academic curriculum. During these years the students are expected to learn detection of incipient carious lesions and take appropriate preventive/restorative measure. Method This study aimed at evaluating the ability of the students and interns to detect only-enamel proximal caries on the five digital bitewing radiographs. The digital bitewing radiographs were having incipient carious lesions involving enamel on proximal surface of mandibular first molars. Results A total of 101 participants (M = 29, F = 72) from fifth (D5) and sixth (D6) years of dentistry evaluated the radiographs and the KR20 values for D5, D6, and total sample were 0.79, 0.64, and 0.41 respectively. Conclusion Overall students' assessment of detection of incipient carious lesion was low. There is need to enhance clinical and radiological cognitive skills among students with emphasis on interdisciplinary learning objectives.

Ability of a Blue Hemoglobin-Based Liquid as a Novel Technology to Stain Initial Enamel Demineralization: A Proof-of-Concept in vitro Study.

During orthodontic treatment, enamel demineralization can occur. Its early detection is the basis for efficient preventive measures to arrest or remineralize lesions. In the present study, the application of a novel blue hemoglobin-based liquid (BlueCheck) was evaluated as proof of concept for detection of artificially demineralized smooth surfaces. 60 samples from extracted human posterior teeth were randomly assigned to four groups (15 per group). In 30 of these samples (groups A and B), superficial enamel was removed to create a ground surface. On the surface of other 30 samples (group C and D), orthodontic metal brackets were bonded. On each surface, BC liquid was applied and rinsed with water after 3 min (baseline). All surfaces were checked by two independent observers for presence of blue areas. On each sample, one side was covered by nail varnish to protect this enamel part from demineralization. The samples were demineralized with lactic acid (pH 4.6) for 7 days (group A and C) and 14 days (group B and D), respectively. Mineral loss was determined using quantitative light-induced fluorescence after demineralization. BlueCheck dye was again applied on the samples and evaluated for presence of stained areas. Histological sections were prepared from randomly selected samples and lesion depth was measured. Kruskal-Wallis test was used for group comparison (α = 0.05). After demineralization, median ΔF value for all samples was -8.25% indicating the presence of an initial demineralization. The difference of ΔF values was not statistically significant between samples at 7 or 14 days of demineralization, nor for samples with and without orthodontic brackets (p = 0.13). At baseline, none of the sample surfaces showed discoloration, whereas a distinctive blue color was visible after demineralization in all samples exposed to acid-exposed areas, corresponding to 100% sensitivity. The internal control surfaces (without demineralization) did not show any staining, corresponding to 100% specificity. Histologically measured lesion depths ranged between 200 and 254 µm. In this in vitro study, staining of demineralized enamel surface areas were shown to be reliable. Based on our results, this easily applicable product seems useful to be an adjuvant method to clinical examination to monitor oral health during an orthodontic treatment on tooth surfaces after removal of dental biofilm.

Three-dimensional characterization of naturally developed early caries lesions using high-resolution micro-computed tomography.

OBJECTIVES: The goal of this micro-Computed-Tomography (µCT) study was to characterize the structural parameters of natural, early proximal enamel caries lesions and correlate them with two-dimensional radiographic findings. METHODS: Extracted human premolar teeth with ICDAS score 2 proximal lesions were examined using visual-tactile, µCT and simulated bitewing radiographs (BTX). Sound enamel and caries-lesions' structural and mineral density (MD) parameters were analyzed which included surface layer (SL) status and thickness, depth of lesion, and MD. RESULTS: Thirty-six extracted premolars with 54 proximal early enamel caries lesions were analyzed. Lesions varied notably in lesion depth and MD. SL thickness ranged between 20 and 139µm. Three teeth (5.6%) had micro-cavitations upon the µCT examination despite being "clinically" non-cavitated. Cavitation status had no significant association with µCT nor BTX radiographic depth. Depth of lesions correlated weakly but statistically significantly with mineral loss (ML) at body of lesion (r=0.301, p=0.027). SL thickness also correlated negatively with ML at SL (r=-0.501, p<0.001). CONCLUSIONS: Early proximal enamel lesions with ICDAS 2 score as determined by visual-tactile examination exhibited a wide range of lesion parameters and cavitation status when examined by µCT. Visual-tactile examination may fail to detect micro-cavitations in enamel surface that are detectable by µCT. CLINICAL SIGNIFICANCE: Clinicians have direct access to early proximal enamel lesions during orthodontic separation, exfoliation, extraction or restoration of adjacent teeth. This study invites the clinician to consider more decisive management options in high risk individuals (e.g. micro-invasive techniques), given the finding of vast structural variability of such lesions.

Advanced materials for enamel remineralization.

Dental caries, a chronic and irreversible disease caused by caries-causing bacteria, has been listed as one of the three major human diseases to be prevented and treated. Therefore, it is critical to effectively stop the development of enamel caries. Remineralization treatment can control the progression of caries by inhibiting and reversing enamel demineralization at an early stage. In this process, functional materials guide the deposition of minerals on the damaged enamel, and the structure and hardness of the enamel are then restored. These remineralization materials have great potential for clinical application. In this review, advanced materials for enamel remineralization were briefly summarized, furthermore, an outlook on the perspective of remineralization materials were addressed.

Is Silver Diamine Fluoride Effective in Arresting Enamel Caries? A Randomized Clinical Trial.

Background: There is limited information on the effectiveness of 38% silver diamine fluoride (SDF) in managing enamel caries. Objective: This study aimed to compare effectiveness of 38% SDF and 5% Sodium fluoride (NaF) varnish in arresting enamel caries in young children when applied semiannually over 18 months. Methods: A randomized controlled trial was conducted on children aged 1−3 years who had at least one active carious surface. They were allocated into two groups: Group 1 (38% SDF) and Group 2 (5% NaF varnish). Visual-tactile examination was used to assess extent of carious lesions. Enamel caries that did not progress to dentin were classified as having caries arrest. Intention-to-treat analysis was performed. Results: At baseline, 290 children with 1974 tooth surfaces with enamel caries were recruited. Caries arrest rates at the tooth surface level in Group 1 and Group 2 were 59.1% and 58.8%, respectively (p = 0.873), at 18 months. The multilevel logistic regression analysis revealed that tooth position, tooth surface, extent of enamel caries at baseline, caries experience, and brushing with fluoride toothpaste influenced caries arrest (p < 0.05). Conclusion: The semiannual application of 38% SDF and 5% NaF varnish had comparable effectiveness in arresting enamel caries in primary teeth.

Attenuation of near-ultraviolet, visible and near-infrared light in sound and carious human enamel and dentin.

OBJECTIVES: This in vitro study aimed to investigate the optical attenuation of light at 405, 660 and 780 nm sent through sound and carious human enamel and dentin, including respective individual caries zones, as well as microscopically sound-appearing tissue close to a carious lesion. MATERIALS AND METHODS: Collimated light transmission through sections of 1000-125-µm thickness was measured and used to calculate the attenuation coefficient (AC). The data were statistically analysed with a MANOVA and Tukey's HSD. Precise definition of measurement points enabled separate analysis within the microstructure of lesions: the outer and inner halves of enamel (D1, D2), the translucent zone (TZ) within dentin lesions and its adjacent layers, the enamel side of the translucent zone (ESTZ) and the pulpal side of the translucent zone (PSTZ). RESULTS: The TZ could be distinguished from its adjacent layers and from caries-free dentin at 125 µm. Sound-appearing dentin close to caries lesions significantly differed from caries-free dentin at 125 µm. While sound and carious enamel exhibited a significant difference (p < 0.05), this result was not found for D1 and D2 enamel lesions (p > 0.05). At 405 nm, no difference was found between sound and carious dentin (p > 0.05). CONCLUSIONS: Light optical means enable the distinction between sound and carious tissue and to identify the microstructure of dentin caries partially as well as the presence of tertiary dentin formation. Information on sample thickness is indispensable when interpreting the AC. CLINICAL RELEVANCE: Non-ionising light sources may be suitable to detect lesion progression and tertiary dentin.