Assessment of Remineralization Ability of Different Fluoride Varnishes on Artificial Enamel Lesion of Primary Teeth - A Comparative Study.

Aim: The current study's aim was to evaluate the potential of various fluoride varnishes to remineralize artificial enamel lesions on primary teeth. Materials and Methods: For the study, 90 deciduous molar teeth that were implicated for extraction were taken. A window region with a size of 3 × 3 mm was located in the middle of the tooth's coronal surface. The remaining portion was given a coat of nail polish and given time to dry. A demineralizing solution was used to create the artificial enamel lesion. The samples were randomized into three experimental groups at random, with 30 samples in each group. Group 1: Application of Clinpro White Varnish, Group 2: Application of Duraphat Varnish, and Group 3: Application of MI Varnish. After 14 days, samples from each group were examined under scanning electron microscopy at a magnification of 1000× to determine whether remineralization had occurred. Microhardness was also determined using a microhardness tester. Result: Before the intervention, the mean demineralized enamel lesion in the Clinpro White Varnish group was 134.44 ± 0.04, in the Duraphat Varnish group was 133.76 ± 0.12, and in the MI Varnish group was 133.89 ± 0.08. After intervention, the maximum remineralized area was found in the MI Varnish group (82.74 ± 0.18) followed by the Clinpro White Varnish group (101.43 ± 0.16) and the Duraphat Varnish group (104.11 ± 0.10). After the intervention, there was a statistically significant difference found between the groups. After the intervention, the maximum microhardness mean value improved in the MI Varnish group (257.03 ± 1.09 to 261.18 ± 1.20) followed by Clinpro White Varnish (258.78 ± 1.64 to 260.10 ± 1.22) and Duraphat Varnish group (255.24 ± 1.51 to 258.02 ± 0.89). Conclusion: According to the findings of the current investigation, all of the varnishes utilized in this in vitro experiment are capable of correcting early enamel defects on primary teeth. However, MI Varnish group was very effective compared to the Clinpro White Varnish group and the Duraphat Varnish group.

Surface topography and spectrophotometric assessment of white spot lesions restored with nano-hydroxyapatite-containing universal adhesive resin: an in-vitro study.

BACKGROUND: White spot lesion (WSL) is a main shortcoming accompanied by orthodontic treatment. It impairs the esthetic, surface hardness, and surface texture of enamel. So, this study was conducted to analyze the surface characteristics and color change of white spot lesions treated with nano-hydroxyapatite (nHA)-enriched universal adhesive resin. MATERIALS AND METHODS: Eighty sound human permanent molars crowns were sectioned into two halves, producing 160 specimens. 16 specimens were left untreated, and 144 specimens were artificially-demineralized to generate WSLs. The specimens were classified according to the treatment approach applied as follows: I; Sound enamel, Group II; artificially-created WSLs, Group III; ICON resin-restored WSLs, Group IV; Universal adhesive resin-restored WSLs, Group V; 0.5 wt% nHA-containing universal adhesive resin-restored WSLs, Group VI; 1 wt% nHA-containing universal adhesive resin- restored WSLs, and Group VII; 3 wt% nHA-containing universal adhesive resin-restored WSLs, Group VIII; 5 wt% nHA-containing universal adhesive resin-restored WSLs, Group IX; 7 wt% nHA-containing universal adhesive resin-restored WSLs, and Group X; 10 wt% nHA-containing universal adhesive resin-restored WSLs. Some surface characteristics and color changes were assessed. Data was collected and analyzed statistically using ANOVA and the Tukey test at p < 0.05. RESULTS: Surface microhardness of WSLs was significantly improved with all investigated ratios of nHA-containing universal adhesive (p < 0.0001), with the highest mean belonging to 10 wt% nHA-containing universal adhesive resin treated WSLs. All ratios of nHA-containing universal adhesive resin significantly reduced the surface roughness of WSLs (p < 0.0001). The investigated ratios of 1, 3, 5, 7, and 10 wt% nHA-containing universal adhesive resin treatment approach could mask the WSLs significantly (p < 0.0001). CONCLUSIONS: Nano-hydroxyapatite-containing universal adhesive is a promising contemporary approach for the management of WSLs, coupled both the remineralizing concept and the minimally invasive resin infiltration.

Comparative assessment of the remineralization characteristics of nano-hydroxyapatite extracted from fish scales and eggshells.

OBJECTIVES: Dentine hypersensitivity (DH) is a common concern in dentistry that has the potential to restrict daily activities and harm a person's quality of life. In this study, the remineralization characteristics of nano-hydroxyapatite (nHAp) extracted from waste eggshells and fish scales were comparatively assessed. MATERIALS AND METHODS: The extraction methods used to obtain nHAp from both fish scales and eggshells are also described. The effect of the extraction process and bio-waste source on the physicochemical characteristics of the nHAp such as Ca/P ratio, functional groups, crystallinity and phase change, and surface morphology are presented in the study. The remineralization properties were evaluated using dentine models (n = 15). A field scanning electron microscope was used to evaluate the effectiveness of the dentine tubules occlusion. The percentage occluded area for all the specimens was evaluated statistically using a one-way analysis of variance (α = 0.05). RESULTS: The results showed that there were variations in the physicochemical characteristics of the nHAp extracted, including the crystallinity, particle size, and surface morphology, and buffering effects against citric acids. The EnHAp extracted from eggshells had higher crystallinity, superior buffering effects, and smaller particle size compared to the nHAp extracted from fish scales, making it a more favourable material for remineralization of teeth. The statistical evidence showed that there were statistically significant differences in the dentine occluding properties measured in the nHAp (p < 0.001). The highest mean % occluded area was measured with the EnHAp group. CONCLUSIONS: The findings of this study provide insights into the use of bio-waste materials for the development of sustainable and effective products for oral health care.

In vitro remineralization assessment of enamel subsurface lesions using different percentages of surface reaction-type pre-reacted glass-ionomer containing gum-based material.

OBJECTIVE: To identify the remineralization activity of enamel subsurface lesions using different percentages of surface pre-reacted glass-ionomer (S-PRG) filler containing gum-base material. METHODS: Gum extracts from gum-base materials containing 0wt%, 5wt%, and 10wt% S-PRG filler were prepared as GE0, GE5, and GE10, respectively. A total of 50 bovine enamel specimens were used, and the polished enamel surface of a 3 × 3 mm2 window area was exposed. The specimens were then subjected to a demineralization solution for seven days to create a subsurface enamel lesion. Remineralization was then conducted for seven days using a protocol whereby the specimens were immersed three times a day in prepared gum extracts (0wt%, 5wt%, and 10wt%) and artificial saliva of pH 7 (Control) for 20 min at 37 °C. Thereafter, remineralization assessment was performed by using Swept Source Optical Coherence Tomography (SS-OCT) and micro-computed tomography (µCT). Surface morphology and elemental analysis were conducted by scanning electron microscopy (SEM) and energy-dispersive X-ray spectrometry (EDS). RESULTS: The depths of the demineralized lesions in the GE5 and GE10 groups were significantly lower than those of the Control and the GE0 groups. SEM observations of the enamel surface morphology of the GE5 and GE10 groups indicated remineralization with S-PRG filler-related elements present. CONCLUSION: The GE5 and GE10 S-PRG filler containing gum-base materials showed significantly improved surface remineralization and reduced demineralization of the enamel lesions. EDS analysis suggested that the released ions from the S-PRG filler might be responsible for surface remineralization. CLINICAL SIGNIFICANCE: The S-PRG filler containing gum-base material may have a significant remineralization effect and improve the surface morphology of enamel subsurface lesions.

Assessment of the Remineralizing Potential of Biomimetic Materials on Early Artificial Caries Lesions after 28 Days: An In Vitro Study.

This study aimed to evaluate the loss of mineral content in the enamel surface in early artificial lesions and to assess the remineralizing potential of different agents by means of SEM coupled with energy-dispersive X-ray analysis (EDX). The analysis was performed on the enamel of 36 molars divided into six equal groups, in which the experimental ones (3-6) were treated using remineralizing agents for a 28-day pH cycling protocol as follows: Group 1, sound enamel; Group 2, artificially demineralized enamel; Group 3, CPP-ACP treatment; Group 4, Zn-hydroxyapatite treatment; Group 5, NaF 5% treatment; and Group 6, F-ACP treatment. Surface morphologies and alterations in Ca/P ratio were evaluated using SEM-EDX and data underwent statistical analysis (p < 0.05). Compared with the sound enamel of Group 1, the SEM images of Group 2 clearly showed loss of integrity, minerals, and interprismatic substances. Groups 3-6 showed a structural reorganization of enamel prisms, interestingly comprising almost the entire enamel surface. Group 2 revealed highly significant differences of Ca/P ratios compared with other groups, while Groups 3-6 showed no differences with Group 1. In conclusion, all tested materials demonstrated a biomimetic ability in remineralizing lesions after 28 days of treatment.

Assessment of the Remineralizing Efficacy of Grape Seed Extract vs Sodium Fluoride on Surface and Subsurface Enamel Lesions: An In Vitro Study.

AIM: The aim of this study was to evaluate the efficacy of grape seed extract (GSE) on remineralization of surface and subsurface enamel lesions compared to that of sodium fluoride (NaF). MATERIALS AND METHODS: A total of 20 intact bovine incisor crowns were separated from their roots and immersed in a demineralizing solution for 96 hours at 37°C to create artificial enamel lesions. The specimens were randomly divided into two groups (n = 10): 6.5% GSE solution and 1000 ppm NaF solution. The specimens were subjected to six daily pH cycles for 8 days. The microhardness test was carried out at three different stages: baseline, after artificial caries formation, and after pH cycling. Raman spectroscopy was used to evaluate the depth of enamel remineralization. Surface morphology and elemental analysis were assessed using a scanning electron microscope (SEM) and an energy dispersive X-ray (EDX) spectroscope, respectively. Statistical analysis was performed using SPSS 22.0 at a significance level of p ≤ 0.05. RESULTS: There was a significant increase in the mean values of enamel surface microhardness after pH cycles in the two groups compared to after artificial caries formation, but there was no significant difference between both groups. The B-type carbonate/phosphate (Ca/P) ratio at 10 and 40 µm depth revealed no significant difference between the two groups. Scanning electron microscope micrograph revealed occlusion of porosities and particle precipitation on the enamel surface of the two groups, while EDX results for the Ca/P ratio of the GSE and NaF groups were 1.59 and 1.60, respectively. CONCLUSION: Grape seed extract and NaF are equally effective in remineralizing surface and subsurface artificial enamel lesions. CLINICAL SIGNIFICANCE: Grape seed extract can be considered a promising herbal material and a safe alternative to traditional NaF for the noninvasive treatment of enamel lesions.

Qualitative and Quantitative Assessment of Remineralizing Effect of Prophylactic Toothpaste Promoting Brushite Formation: A Randomized Clinical Trial.

BACKGROUND: Currently various studies are conducted to improve the effect of existing and developing new remineralizing agents. One of the trends in remineralizing therapy is the development of toothpaste allowing brushite crystals formation in the demineralized lesions of hard tooth tissues. AIM: The aim of this study was to assess the effect of toothpaste, forming a brushite, on the functional acid resistance of enamel and the speed of its remineralization. MATERIALS AND METHODS: This was a randomized controlled double-blind clinical study. Sixty consent patients aged 20-25 years were enrolled in the three groups: test group (n = 20), positive control group (n = 20), and negative control group (n = 20), which used brushite-forming toothpaste, toothpaste with hydroxyapatite (HAP), and toothpaste without remineralizing agents, respectively. The hygiene indices, the rate of enamel remineralization, the dynamics of acid resistance of enamel, and the level of enamel sensitivity were determined at baseline, after 2 and 4 weeks to assess the effectiveness of toothpastes. Friedman rank sum test (for related variables) and the Kruskal-Wallis rank sum test (for independent variables) with Nemenyi post hoc test were used for statistical comparisons. RESULTS: The study test and positive control groups showed significantly greater acid resistance of enamel (P > 0.05) and rate of its remineralization at the study endpoints as compared with negative control group.In the test and positive control groups, Schiff index values significantly decreased after 4 weeks, whereas in the negative control group no significant differences were observed at the study time points. The oral hygiene level improved significantly after 2 and 4 weeks in all groups. CONCLUSION: The 30-day use of paste that promotes brushite formation and paste with hydroxyapatite resulted in faster enamel remineralization and higher enamel resistance. Brushite-containing toothpaste may be used as an alternative to HAP containing for remineralizing and desensitizing treatment.

Bioactivity assessment of bioactive glasses for dental applications: A critical review.

OBJECTIVE: In the context of minimally invasive dentistry and tissue conservation, bioactive products are valuable. The aim of this review was to identify, clarify, and classify the methodologies used to quantify the bioactive glasses bioactivity. METHODS: Specific search strategies were performed in electronic databases: PubMed, Embase, Cochrane Library, and Scopus. Papers were selected after a review of their title, abstract, and full text. The following data were then examined for final selection: BAG investigated, objectives, criteria, methods, and outcomes. RESULTS: Sixty-one studies published from 2001 to 2019, were included. The bioactivity of BAG can be evaluated in vitro in contact with solutions, enamel, dentin, or cells. Other studies have conducted in vivo evaluation by BAG contact with dentin and dental pulp. Studies have used various analysis techniques: evaluation of apatite with or without characterization or assessment of mechanical properties. Reprecipitation mechanisms and pulp cell stimulation are treated together through the term 'bioactivity'. SIGNIFICANCE: Based on these results, we suggested a classification of methodologies for a better understanding of the bioactive properties of BAG. According to all in vitro studies, BAG appear to be bioactive materials. No consensus has been reached on the results of in vivo studies, and no comparison has been conducted between protocols to assess the bioactivity of other bioactive competitor products.

Objective and quantitative assessment of caries lesion activity.

OBJECTIVES: Evaluate the ability of objectively measured specular reflection, roughness, and fluorescence change during dehydration to assess caries lesion activity. METHODS: One hundred ninety-five ground/polished 3 × 3 × 2 mm sound human enamel specimens were divided into three groups and demineralized using a multispecies microbial caries model for 3, 6, or 9 days; and then remineralized with 1100 ppm-F as NaF solution for 10 days using a pH-cyclic model. Reflection (amplitude: %), roughness (Ra: µm), fluorescence change during dehydration (ΔQ: %×mm2), and microfocus computed tomography [µ-CT: lesion volume (µm3)] were measured for sound, demineralized and remineralized enamel. The surface was hydrated and fluorescence images were acquired at 1 s intervals for 10 s (ΔQ10). During image acquisition, surface was dehydrated with continuous compressed air. Changes-in-ΔQ per second (ΔQD: %×mm2/sec) at 5 (ΔQD5) and 10 s (ΔQD10) were obtained. RESULTS: Reflection decreased from sound to demineralized groups (p < 0.0001); remineralized groups were higher than demineralized groups (p < 0.001), but not different from sound (p > 0.32). Roughness increased from sound to demineralized groups (p < 0.0001) and remineralized groups were also higher than sound (p < 0.0001). ΔQ10, ΔQD5 and ΔQD10 increased from sound to demineralized groups (p < 0.0001), and remineralized groups decreased compared to demineralized groups (p < 0.05), but was higher than sound (p < 0.0001). The correlations of µ-CT with reflection, roughness, and ΔQ10 were -0.63, 0.71, and 0.82, respectively (p < 0.0001). CONCLUSIONS: Reflection, roughness and ΔQ could distinguish between sound and demineralized enamel. Reflection and ΔQ were able to distinguish between demineralized and remineralized enamel. CLINICAL SIGNIFICANCE: Determination of caries activity, whether a lesion is active or inactive, is an essential and critical component of caries diagnosis. However, especially for enamel lesions, it is difficult to estimate without longitudinal follow-up. Reflection, roughness and fluorescence change during dehydration have the potential to measure caries lesion activity at a-single-appointment.

Micro-computed tomography assessment of root dentin around fluoride-releasing restorations after demineralization/remineralization.

Using micro-computed tomography (micro-CT), this study assessed the inhibitory effect of three different types of restorations on root-caries formation under a cariogenic challenge. Bovine-root dentin blocks with a cylindrical cavity were divided into three restoration groups: a fluoride-free self-etch adhesive and a resin composite (SE-ES); a self-etch adhesive and a resin composite with multi-ion release (FL-BF); and a glass ionomer cement (Fuji-VII). After the restorative procedures, the specimens were stored in artificial saliva for 1 d, then subjected to a demineralization solution for 4 d and a remineralization solution for 28 d. Mineral density and mean mineral loss of dentin around the restorations were measured using micro-CT. The mean mineral loss values of dentin around the restorations were highest among SE-ES restorations and lowest among Fuji-VII restorations. Fuji-VII showed the highest mineral density and the lowest mineral loss after 28 d of remineralization. The observations made by scanning electron microscopy demonstrated that Fuji-VII created the smallest outer lesion followed by FL-BF and SE-ES. Fuji-VII has a larger inhibitory effect on root caries around the restorations and enhances remineralization more effectively than either FL-BF or SE-ES. Multi-ion and fluoride release from the restorative materials may be beneficial for inhibition of root-dentin caries around the restorations.

Assessment of Enamel Surface Microhardness with different Fluoride Varnishes-An In Vitro Study.

AIM: This study aimed to assess the microhardness of the enamel surface after fluoride varnish application. MATERIALS AND METHODS: Thymol of 0.1% in distilled water was used to store the collected healthy sixty teeth. The samples were divided into three groups randomly as per the different applica -tion of fluoride varnish. Group A: Fluor protector varnish (FIV) application, group B: Duraphat varnish application and group C: Bifluorid 10 varnish application. The present study followed the pH cycling protocol. Microhardness tester was used to test the microhardness of enamel surface and was expressed as micro-hardness measurements of Vickers hardness number (VHN) which was performed at baseline, on the 3rd day andon 7th day. RESULTS: At baseline, group A samples mean SMH value was 230.64 ± 12.32 which was slightly more than group B with 229.45 ± 10.22 and group C with 230.10 ± 11.45. There was no significant difference showed with the analysis of variance between the groups. On the 3rd day, there was a slight increase in the mean SMH in group A with 235.39 ± 6.44 and no significant difference between the groups was seen statistically. On the 7th day, the group A showed high SMH value of 262.20 ± 4.89 compared to other groups which didn't show a significantly high statistical difference. CONCLUSION: On conclusion, post-application of fluorprotector varnish showed higher enamel surface microhardness compared to Duraphat and Bifluorid 10 varnishes. CLINICAL SIGNIFICANCE: In young children, fluoride varnishes are effectively used as a noninvasive, anti-caries agent in the treatment of initial caries. Therefore, in routine dental practice, the knowledge about different fluoride varnishes is of importance.

Influences of bicarbonate on processes of enamel subsurface remineralization and demineralization: assessment using micro-Raman spectroscopy and transverse microradiography.

In the present study, we investigated, using micro-Raman spectroscopy (Raman) and transverse microradiography, the influence of bicarbonate [sodium hydrogen carbonate (NaHCO3 )] on the effects of carbonate ions in the mineral phase during demineralization (acid resistance test) of subsurface lesions. Baseline lesions were created by demineralizing bovine enamel, and specimens were then exposed to remineralization solutions containing 0, 5, or 50 mM bicarbonate. Acid resistance tests were performed on remineralized and sound enamel specimens. Raman spectra showed that carbonate and phosphate were incorporated into both surface layers and lesion bodies during remineralization in the presence of bicarbonate. Moreover, the presence of bicarbonate did not affect the rates of remineralization, although the average mineral profiles of remineralized enamel differed from those of sound enamel after acid resistance tests. Raman analyses enabled close evaluation of site-specific characteristics of carbonate and phosphate in subsurface lesions. In conclusion, incorporation of carbonate and phosphate ions into enamel subsurface lesions during remineralization does not affect the magnitude of remineralization or acid resistance.

Infrared Methods for Assessment of the Activity of Natural Enamel Caries Lesions.

New diagnostic methods are needed for the accurate assessment of caries lesion activity to establish the need for surgical treatment. Detection of the highly mineralized surface layer that forms near the surface of the lesions as a result of remineralization is important for diagnosis of the lesion activity. Previous studies have demonstrated that novel imaging methods can be used to detect remineralization of artificial enamel caries lesions. In this paper, the activity of natural enamel caries lesions was assessed in-vitro via detection of the surface layer with PS-OCT and dehydration rate measurements with NIR reflectance and thermal imaging modalities. An automated approach for detecting the surface layer with PS-OCT yielded high sensitivity (= 0.79) and high specificity (= 0.93) with moderate correlation (R2 = 0.5920) with histology. Significant differences in dehydration rate measurements were found between the active and the arrested lesions using both the NIR reflectance and thermal imaging modalities. These results demonstrate that these novel imaging methods are ideally suited for nondestructive, noninvasive and quantitative measurement of lesion activity during a single clinical examination in real-time.

Assessment of simulated lesions on primary teeth with near-infrared imaging.

Previous studies have demonstrated that the structural changes on enamel due to demineralization and remineralization can be exploited through optical imaging methods such as QLF, thermal and NIR imaging. The purpose of this study is to investigate whether PS-OCT and NIR reflectance imaging can be utilized to assess lesion structure in artificial enamel lesions on the smooth surfaces of primary teeth exposed to fluoride. The smooth coronal surfaces of primary teeth (n=25) were divided into 4 windows: sound, demineralization, demineralization with remineralization and APF with demineralization. Windows were treated with either acidulated phosphate fluoride (APF) for 1 minute, a demineralization solution for 4 days, and/or an acidic remineralization solution for 12 days. The samples were imaged using PS-OCT, QLF and NIR reflectance at 1400-1700 nm wavelengths. This study demonstrated that both PS-OCT and NIR reflectance imaging were suitable for assessing lesion structure in the smooth surfaces of primary dentition.

Ultrasonic assessment of the effects of self-assembling peptide scaffolds on preventing enamel demineralization.

OBJECTIVES: This study evaluates the effect of self-assembling peptide P11-4 (Curodont Repair, CDR) on bovine enamel remineralization by measuring changes in ultrasonic propagation velocity. METHODS: Six specimens per group were prepared by sectioning bovine teeth into enamel blocks. These blocks were then immersed in lactic acid buffer solution (pH = 4.75) for 10 min twice a day and stored in artificial saliva. Other specimens were first treated with CDR, followed by a 10-min immersion in the lactic acid buffer solution twice a day, before storage in artificial saliva. The propagation time of longitudinal ultrasonic waves was measured using a pulser/receiver. Six specimens were used for each treatment protocol. The obtained data were statistically analyzed using ANOVA followed by Tukey's honestly significant difference tests (α = 0.05). Specimens were observed using laser scanning microscopy and scanning electron microscopy. RESULTS: Sonic velocity was found to decrease with time for specimens stored in the demineralizing solution. On the other hand, increases in sonic velocity were found for specimens treated with CDR. These specimens also exhibited signs of mineral deposition. CONCLUSIONS: By measuring the ultrasonic propagation velocity, it can be concluded that CDR application has an ability to promote bovine enamel remineralization.

Assessment of remineralization via measurement of dehydration rates with thermal and near-IR reflectance imaging.

OBJECTIVES: Previous studies have demonstrated that the optical changes due to the loss of water from porous lesions can be exploited to assess lesion severity with QLF, thermal and near-IR imaging. Since arrested lesions are less permeable to water due to the highly mineralized surface layer, changes in the rate of water loss can be related to changes in lesion structure. The purpose of this study was to investigate whether the rate of water loss correlates with the degree of remineralization and whether that rate can be measured using thermal and near-IR reflectance imaging. METHODS: Artificial bovine enamel lesions (n=30) were prepared by immersion in a demineralization solution for either 8 and 24 h and they were subsequently placed in an acidic remineralization solution for different periods. The samples were dehydrated using an air spray for 30s and surfaces were imaged using a thermal camera and an InGaAs camera at 1300-1700 nm wavelengths. RESULTS: The area enclosed by the time-temperature curve, ΔQ, from thermal imaging showed significant differences (P<0.05) between the lesion window and other windows. Near-IR reflectance intensity differences, ΔI, before and after dehydration decreased with longer periods of remineralization. Only near-IR reflectance imaging was capable of detecting significant differences (P<0.05) between the different periods of remineralization. CONCLUSIONS: This study demonstrated that both thermal and near-IR reflectance imaging were suitable for the detection of remineralization in simulated caries lesions and near-IR wavelengths longer than 1400 nm are well suited for the assessment of remineralization.

Assessment of remineralization in simulated enamel lesions via dehydration with near-IR reflectance imaging.

Previous studies have demonstrated that near-IR imaging can be used to nondestructively monitor the severity of enamel lesions. Arrested lesions typically have a highly mineralized surface layer that reduces permeability and limits diffusion into the lesion. The purpose of this study was to investigate whether the rate of water loss correlates with the degree of remineralization using near-IR reflectance imaging. Artificial bovine (n=15) enamel lesions were prepared by immersion in a demineralization solution for 24 hours and they were subsequently placed in an acidic remineralization solution for different periods. The samples were dehydrated using an air spray for 30 seconds and surfaces were imaged using an InGaAs camera at 1300-1700 nm wavelengths. Near-IR reflectance intensity differences before and after dehydration decreased with longer periods of remineralization. This study demonstrated that near-IR reflectance imaging was suitable for the detection of remineralization in simulated caries lesions and near-IR wavelengths longer than 1400 nm are well suited for the assessment of remineralization.

In vitro assessment of artificial saliva formulations on initial enamel erosion remineralization.

OBJECTIVES: Various formulations of artificial saliva are present in the literature and little guidance is available on the standardization of type of saliva for use in in vitro protocols for erosive studies. The aim of this study was to evaluate the remineralizing capacity of different formulations of artificial saliva on initial enamel erosive lesion. METHODS: Bovine enamel blocks were subjected to short-term acidic exposure by immersion in citric acid 0.05 M (pH 2.5) for 15s, resulting in surface softening without tissue loss. Then 90 selected eroded enamel blocks were randomly and equally divided into 6 groups according to saliva formulation (n=15): Saliva 1 (contain mucin); Saliva 2 (Saliva 1 without mucin); Saliva 3; Saliva 4; Saliva 5 (contain sodium carboxymethyl cellulose) and control (C) (deionized water). After demineralization enamel blocks were subjected to remineralization by immersion in the saliva's formulations for 2h. Enamel remineralization was measured by superficial hardness test (% superficial hardness change). The data were tested using ANOVA and Tukey's test (p<0.05). RESULTS: All the tested formulations of artificial saliva resulted in significantly higher enamel remineralization compared to control (p<0.001). Saliva 3 showed higher percentage of enamel remineralization than Saliva 5 (p<0.05). CONCLUSIONS: Besides the variety of artificial saliva for erosion in vitro protocols, all the formulations tested were able to partially remineralize initial erosive lesions.

In vivo assessment of secondary caries and dentin characteristics after traditional amalgam restorations.

OBJECTIVE: This study aimed to evaluate in vivo the occurrence of secondary caries and dentin characteristics in permanent molars after traditional amalgam restorations, by means of clinical visual examination, radiographs and laser-induced fluorescence (LF) (DIAGNOdent). METHODS: Thirty first permanent molars of 30 schoolchildren in the 7 to14 year-old age group were included. Caries was removed by hand. Thus, indirect pulp capping was performed with glass-ionomer cement (GIC), the cavity was varnished and amalgam filled. LF was measured before and after cavity preparation and after a 12-month observation period. Dentin color after cavity preparation and after the 12-month observation period was recorded. Recurrent caries was also investigated by visual clinical and radiographic examinations, in addition to dentin thickness between pulp and indirect GIC pulp capping. Data was analyzed by ANOVA for repeated measurements, paired "t" test and descriptive statistic. RESULTS: There were statistically significant differences (P<.05) among LF scores for dentin in all periods evaluated, with the lowest scores shown after 12 month of observation. There was no statistical difference between dentin color after cavity preparation and following 12 months of observation. Moreover, there was no recurrent caries attack at 12-month follow-up; dentin thickness between pulp and indirect GIC pulp capping was similar between baseline and final observation periods. It was concluded that the clinical restorative procedure using hand caries removal, indirect pulp capping with GIC, varnishing and amalgam filling the cavity did not provide secondary caries and increased dentin mineral content after 12 months.