Enamel Windows Research Articles

Effect of N-Acetylcysteine on initial Carious Enamel Lesions in primary teeth: an In-vitro study

BackgroundDental caries initiates with non-cavitated enamel lesions as the first stage. The cariogenic potential of N-Acetylcysteine (NAC) may be due to its usage frequency and form. This study aimed to evaluate the impact of exposure time of NAC on initial enamel caries-like lesions in primary teeth by assessing the morphological alteration using a scanning electron microscope (SEM) and mineral content using energy dispersive x-ray spectroscopy (EDX).MethodsForty primary incisor teeth were randomly divided into 4 groups S, S1, S2, and S3 (10 specimens/group). Teeth crowns were cut from their roots and inserted into an acrylic mold with its buccal surface directed upward. Centrally isolated enamel window (2 × 2 mm) on the tooth was done. Ten specimens were selected to evaluate normal enamel while the remaining thirty specimens were immersed in demineralizing solution for 96 h to produce enamel caries-like lesions. PH cycling was performed by immersing each tooth sample in 20 mL of demineralizing solution for 3 h then, preserved for the remaining day hours in 10 ml of artificial saliva interspersed with treatments applications with 10 ml NAC for 10 min twice a day for one- or three-months different treatment modalities. Thermocycling was done for all specimens then they were subjected to SEM and EDX analysis. ANOVA and Bonferroni post hoc tests were utilized in data analysis.ResultsIn teeth treated by NAC for 3 months (group-S3), SEM images showed severe loss of enamel architecture with large NAC deposits detected. A meaningful difference was observed among different groups concerning calcium, phosphorus, fluoride, ca/P ratio, carbon, nitrogen, and oxygen contents (P < 0.05).ConclusionNAC had a detrimental impact on enamel caries-like lesions in human primary teeth.

Impact of Various Remineralizing Agents on Artificial White Spot Lesion on Primary Teeth-A Comparative Study.

The aim of the current research was to assess the effectiveness of different remineralizing substances on artificial white spot lesions on deciduous teeth. 45 deciduous teeth without dental caries constituted the study group for this in vitro research. A 3 mm by 3 mm window of enamel was uncovered at the occluso-gingival midpoint of the coronal labial surface; an acid-resistant nail varnish was coated alongside the uncovered enamel surface of all specimens, employing vertical strokes. Demineralization was executed for the tenure of 72 hours at 37°C temperature in an incubator. The forty-five specimens, fifteen in each group, were assigned to the investigational groups plus a control group as: Group A: Control, Group B: Calcium sucrose phosphate (CaSP), Group C: Casein phosphopeptide-amorphous calcium phosphate-fluoride (CPP-ACPF). Microhardness tester was employed for testing the microhardness of the enamel surface using a Vickers diamond indenter laden with twenty-five milligrams for approximately ten seconds. Vickers hardness number (VHN) calculations for the microhardness were performed at baseline and on the fourteenth day. The CPP-ACPF group exhibited greater mean microhardness value at 236.14 ± 2.12, in pursuit by CaSP group with a score of 231.98 ± 3.16 and then the control group at 220.22 ± 5.08. An extremely statistically significant difference was seen amid the groups. The current research arrived at a conclusion that both the remineralizing substances were certainly efficient in handling early dental caries, and additionally, casein phosphopeptide-amorphous calcium phosphate-fluoride (CPP-ACPF) was found highly efficient as a remineralizing substance, in pursuit by calcium sucrose phosphate (CaSP).

Comparing the effect of animal and plant-based yogurt extracts on enamel demineralization: an in vitro study.

Yogurt, due to its rich casein phosphopeptide (CPP) content could promote remineralization of enamel. Contrary to the age-old usage of animal milk based yogurt, vegan dairy products are gaining momentum due to multiple reasons. Considering this change, the aim of the present study was to assess the in vitro effect of animal and plant-based yogurt extracts on demineralization of enamel. Enamel windows were prepared on the crowns of sixty premolar teeth using nail paint. Teeth were divided into four groups of fifteen each and were treated with distilled water, demineralizing agent, solution with a mixture of demineralizing agent and yogurt supernatants, respectively for 96 hrs. Quantitative analysis was done using EDXRF (baseline and postexperimental calcium and phosphorus content). Additionally, confocal microscopic analysis was performed to assess the extent of demineralization. The animal-based yogurt (Group III) had the highest post experimental calcium value (mean±SD=81.15±5.02) and positive percentage of change in calcium level (15%; P=0.007) among the groups. This was followed by plant-based yogurt (Group IV) (mean calcium= 76.18±5.12; positive percentage change =8.11%; P=0.003). Animal based yogurt could provide higher protection against enamel demineralization when compared to plant-based yogurt.

Effect of different etching time on etch pattern and etch depth using 1% phytic acid in primary teeth – A Scanning Electron Microscopic study

This study aimed to evaluate the effect of varied etching time on etch pattern and etch depth with 1% phytic acid in primary teeth . Thirty extracted human non-carious primary tooth crowns were sectioned and varnished leaving 4 mm enamel window on buccal surfaces. The teeth were then divided into 3 groups corresponding to etching time 15, 30 and 60 seconds to estimate etch pattern and depth. One percent phytic acid is used for etching the enamel surfaces. The etch pattern and etch depth was observed using Scanning Electron Microscopy (SEM). The results demonstrated, no differences in etch patterns in all 3 groups irrespective of etch time. Etch depth on enamel surfaces after etching for 15 seconds (group I) and 30 seconds (group II) were similar, but a greater increase in etch depth were observed after 60 seconds (group III) of etching. One percent phytic acid produced 3 types of etch patterns, among which hollowing of prism core with relatively intact peripheral region etch pattern were predominant irrespective of varying etch time. Etch depth on enamel surfaces increased with increase in etching time. This is the first study, • To evaluate the effect of 1% phytic acid as an etchant in primary teeth. • To evaluate the etch pattern using 1% phytic acid in primary teeth using Scanning Electron Microscopy. • To estimate the etch depth using 1% phytic acid in primary teeth using Scanning Electron Microscopy. • To evaluate the effect of varied etching time using 1% phytic acid in primary teeth.

Effects of Different Bleaching Agents on the Surface Topography and the Microhardness of Artificial Carious Lesions.

Objectives The aim of this study was to evaluate the effects of in-office and at-home bleaching agent applications on the surface topography and microhardness of artificially demineralized enamel. Materials and Methods A total of 224 enamel specimens were prepared using bovine sound central incisors. 4 mm × 4 mm enamel windows were exposed on the buccal surfaces covering the remaining surface with nail varnish. Samples were immersed in a demineralizing solution for 16 hours to produce artificial caries lesions, then divided into four groups according to the bleaching agent’s type and concentration. Group I; in-office bleaching 35% hydrogen peroxide (HP) (Whiteness HP Maxx; FGM, Brazil), Group II and Group III at-home bleaching 16 and 22% carbamide peroxide CP, respectively (Whiteness Perfect). Group IV; control (not bleached). The microhardness Vickers hardness number (VHN) was measured at the baseline, after demineralization, and after bleaching consequently. The micro-surface changes of the enamel surface after demineralization and bleaching were evaluated by scanning electron microscope (SEM). Statistical Analysis Data were evaluated by the one-way analysis of variance (ANOVA) test followed by Post Hoc Tukey’s and Fisher’s least significant difference. Tow- sided p -values were considered statistically significant at p ≤ 0.05. Results A significant reduction was noticed in the enamel microhardness after demineralization p < 0.05. However, there is no statistically significant difference between the mean VHN of the demineralized and bleached enamel ( p > 0.001). SEM images showed significant changes on the surface of the demineralized enamel after bleaching (pattern type III). Conclusions The low and high concentrations of HP and CP bleaching agents increased the demineralization severity of artificial caries lesions without significantly altering their microhardness values.

Amelogenin Peptide-Chitosan Hydrogel for Biomimetic Enamel Regrowth.

We designed synthetic peptides that have demonstrated an effective remineralization potential to restore incipient enamel decay. In order to develop a clinically viable approach we incorporated the amelogenin-derived peptides P26 and P32 into chitosan hydrogel and examined their efficacy in the remineralization of enamel. Peptides in chitosan exhibited increased stability in vitro as compared to peptides in solution at room temperature and at 37°C. Tooth models for enamel erosion (sections) and white spot lesions (blocks) were subject to periods of demineralization. Treatment groups were subjected to remineralization in artificial saliva in the presence of P26 and P32 in solution and in chitosan hydrogel (P26-CS and P32-CS). Quantitative light-induced fluorescence (QLF) was employed to analyze mineral density following demineralization and remineralization across all the treatment groups. Scanning electron microscopy and nanoindentation were used to characterize the surface structure and mechanical strength of regrown enamel. Control enamel sections treated in artificial saliva demonstrated randomly distributed, tiny, needle-shaped crystals with a low packing density and porosities displaying mineralization defects. In samples treated with P26-CS or P32-CS a denser coating of organized hydroxyapatite (HAP) crystals was formed covering the entire surfaces of demineralized enamel window. The hardness and modulus of enamel surfaces were increased after treatment with P26-CS and P32-CS with no significant difference in the mechanical properties between the two peptide hydrogels. Analysis of mineral density by QLF showed that in enamel sections P26 peptide alone or P26-CS significantly enhanced the remineralization. In enamel blocks P26 in solution had a better efficacy than P26-CS.

Influence of fluoride preparations for the prevention of dental caries on the enamel solubility

The aim of the study is to evaluate the effectiveness of a number of popular fluorine-containing caries prophylactic drugs by determining the level of solubility of tooth enamel in laboratory conditions. For testing fluorine-containing preparations, three observation groups were formed: Group I - using the preparation with the content of fluorides 4%; Group II - with a preparation for deep fluoridation of enamel, consisting of a liquid saturated with fluorine, copper and magnesium, as well as a suspension of calcium hydroxide; Group III - with a three-component gel based on carboxymethyl cellulose (CMC) the content of fluorides 1.5%. The study was carried out by using the method of «enamel windows» and modeling in the laboratory the processes of both natural and pathological solubility of tooth enamel and determining the level of its solubility by analyzing the decalcifying solution of the oral fluid for the content of calcium and phosphorus ions in it. In the course of the study of fluorinated karyoprophylactic preparations on the enamel surface, according to the observation group, the most active karyoprophylactic fluorinated compositions were identified. The data obtained from laboratory studies allow us to formulate clear recommendations for practical health care for the most effective use of the properties of the tested fluorine-containing drugs for prophylactic purposes or in relation to the therapy of focal demineralization of enamel: to obtain the most effective result of the prevention of dental caries in the conditions of practical dental treatment, we recommend applying gel fluoride preparations, and in the treatment of initial caries of the enamel of the teeth, give preference to systems for deep fluoridation of the enamel of the teeth.

Impact of early biofilm on the assessment of initial enamel erosion with swept-source optical coherence tomography.

Objective: This study examined the impact of early biofilm on the tooth surface, during the assessment of initial enamel erosion using swept-source optical coherence tomography (SS-OCT). Method and materials: Forty-five enamel windows of 2 × 4 mm2 were prepared on 23 extracted human teeth. The specimens were exposed to citric acid (pH 3.2) for 30 minutes and randomly divided into three groups (n = 15): Group 1, no biofilm; Group 2, 1-day-old biofilm; and Group 3, 3-day-old biofilm. Specimens in Groups 2 and 3 were inoculated with oral bacteria (Streptococcus sanguinis, Streptococcus mitis, and Actinomyces naeslundii) to produce early laboratory-cultivated biofilms for 1 and 3 days respectively. Surface microhardness (SMH) measurements were taken at pre- (t1) and post-erosion (t2); and SS-OCT scans were done at t1, t2, and post-biofilm cultivation (t3). Integrated reflectivity (IR) of the tooth-air interface (IRsurface) and enamel (IRenamel) were computed from the mean A-scans. Statistical analysis was performed using paired t tests and one-way ANOVA (α = .05). Results: A significant increase in IRenamel was observed at t2 (P < .05). At t3, IRsurface between Group 1 (control) and Group 2 (P = .012) as well as Group 3 (P = .001) were significantly different. Significant variances in IRenamel were perceived between t2 and t3 for Groups 2 and 3 but not for Group 1. Conclusion: As early biofilm affected SS-OCT assessment of initial enamel erosion, they should be removed from the tooth surface prior to OCT procedures..

PH-responsive calcium and phosphate-ion releasing antibacterial sealants on carious enamel lesions in vitro

ObjectiveNanoparticles of amorphous calcium phosphate (NACP) have shown beneficial effects of a robust release of calcium and phosphate ions at low pH. Here we examined the effect of NACP combined into antibacterial/rechargeable sealant formulations on the mineral content of artificial carious enamel during pH-cycling mimicking intraoral conditions. Materials and MethodsNACP and a quaternary ammonium methacrylate (DMAHDM) were synthesized. Three resin sealants were formulated: "base formulation" (without NACP and DMAHDM, used as control); "NACP on the base formulation" (with 20 wt.% NACP); "NACP on the antibacterial formulation" (with 20 wt.% NACP and 5 wt.% DMAHDM). Standardized enamel windows on sealed non-carious human molars were demineralized and randomly divided into four groups: three groups of teeth sealed with the experimental materials and one group of teeth without sealant application used as negative control. The teeth were exposed to pH cycling regime. The changes in the mineral content of enamel were assessed by quantitative surface hardness loss in percentage (%SHL) and qualitative analyses via scanning electron microscopy/energy-dispersive X-ray spectroscopy (SEM-EDX) and polarized light microscopy (PLM). ResultsThe contact with NACP-containing formulations provoked significant lower %SHL on sealed enamel (p < 0.05) in comparison to control groups. This outcome was supported by the results of SEM-EDX, in which the enamel presented higher percentages of calcium and phosphate than control groups. PLM showed less enamel superficial demineralization around the sealants containing NACP. ConclusionNACP incorporated into an antibacterial sealant protected the enamel against demineralization. pH-responsive calcium and phosphate-ion releasing sealants with antimicrobial and rechargeable properties may be a reliable complementary approach for caries management. Clinical significanceDental caries is the most common childhood disease. Enamel demineralization represents the initial stage of carious lesion formation and may lead to invasive dental procedures. We explored the role of amorphous calcium phosphate (NACP) in a newly-developed antibacterial and rechargeable dental sealant formulation as a preventive approach.

Resistance of chicken egg shell powder treated demineralized enamel to further acidic challenges

Objective The purpose of this in-vitro study was to quantitatively evaluate the remineralization potential of chicken egg shell powder (CESP) solution on early demineralized enamel lesions and the resistance of the treated enamel surfaces to further acidic challenges. Patients and methods A 3 × 3 mm enamel windows were done on the buccal surface of 36 sound, freshly extracted human first premolars for orthodontic purposes. Specimens were randomly divided according to the period of treatment with CESP solution into two equal groups (18 each). Ten specimens from each group were examined throughout the steps of the study with energy dispersive radiograph analysis for their calcium (Ca) and phosphorus (P) content. Enamel surface topography of the remaining eight specimens was examined under scanning electron microscope (two specimens for each step). Initial enamel lesions were created by immersion of the specimens separately in 10 ml of a demineralizing solution at 37°C for 96 h. For treatment specimens of group I were individually immersed in CESP solution once daily for 12 min and kept in artificial saliva at 37°C for the rest of the day, for 7 consecutive days. Specimens of group II were treated twice daily with a 12 h interval between both immersions following the cycle mentioned before. The treated specimens were then subjected to a 5 days' pH cycling regimen consisting of demineralization for 3 h, and remineralization for 21 h. The collected data were tabulated and statistically analyzed. Results Group II recorded a statistically significant higher Ca value and Ca/P ratio after treatment and pH cycling compared to group I (P = 0.000) as detected by independent t test. Regarding the P content value recorded after treatment it was significantly lower for group II versus group I (P = 0.000). While no significant difference was found between both groups after pH cycling (P = 0.755). Scanning electron microscope findings were found supporting the previous results. Clinical significance CESP solution provided a significant remineralization potential of the human initially demineralized enamel lesions.

Enamel Erosion: A Possible Preventive Approach by Casein Phosphopeptide Amorphous Calcium Phosphate-An In Vitro Study.

ContextSeveral efforts were made in order to alter the compositions of acidic food items concerning their properties to be able to reduce their erosivity potential. The addition of combinations of calcium and phosphate salts to these food products has grabbed great interest.AimIn vitro evaluation of the effect of the addition of 0.2% w/v casein phosphopeptide–amorphous calcium phosphate (CPP–ACP) to four commonly available beverages (of which two were carbonated) on enamel erosion.Materials and methodsSound-extracted human third molar teeth were taken, and enamel sections (n = 270) were made and polished. Acid-resistant nail varnish was painted to create an exposed enamel window of 1 mm2, followed by testing of the four soft drinks and distilled deionized water (DDW). Every drink was evaluated with and without the addition of 0.2% w/v CPP–ACP. The enamel specimens were kept in 50 mL solution at 37°C for 30 minutes, rinsed, and then varnish was removed. All samples were then profiled using white-light profilometer, and erosive depths were recorded.Statistical analysisOne-way analysis of variance test and post hoc Tukey test.ResultsEnamel erosion was created by all the soft drinks tested, but the addition of 0.2% w/v CPP–ACP has remarkably reduced (p value < 0.05) erosive depths in all test solutions compared to solutions without CPP–ACP. The erosive depths for solutions with DDW did not vary much from those with 0.2% CPP–ACP.ConclusionAddition of 0.2% w/v CPP–ACP to the soft drinks has remarkably reduced their erosivity potential.How to cite this articleVelagala D, Reddy VN, Achanta A, et al. Enamel Erosion: A Possible Preventive Approach by Casein Phosphopeptide Amorphous Calcium Phosphate—An In Vitro Study. Int J Clin Pediatr Dent 2020;13(5):486–492.

Evaluation of the Effectiveness of Olive Oil on the Prevention of Dental Erosion: An In vitro Study

Aim: The aim of this study was to explore the anti-erosive effect of olive oil against citric acid on bovine teeth and to compare the effectiveness with that of fluoride varnish. Materials and Methods: An observational analytical cross-sectional study among forty recently extracted bovine incisor teeth. From each tooth, a cubic of 4 mm × 4 mm was cut. Five surfaces of the cubic were coated by nail varnish leaving only the enamel window uncovered. The specimen was divided into four groups randomly: Group 1: five teeth (control group) nothing used, Group 2: five teeth immersed in olive oil for 6 h, Group 3: five teeth immersed in olive oil for 48 h, and Group 4: 10 teeth immersed in fluoride varnish 48 h. Then, each specimen was immersed in citric acid (pH: 2.3) for 15 and 30 min. The amount of calcium dissolved was measured by atomic absorption spectrophotometer. Different variables were statistically compared by t-test and ANOVA test with the level of significant set at P≤ 0.05. Results: The mean of calcium dissolution among the control group at 15 min was 2.8 mg/dl, while dissolution in 30 min was 6.1 mg/dl. When comparing the effect of exposure time duration of all specimens in citric acid, it was found that calcium dissolution increased in 30 min exposure than in 15 min exposure. Emersion of teeth in olive oil for 6 h was effective in reducing enamel erosion when exposed to citric acid 1% at 15 min, while in 30-min exposure to citric acid was less effective and to a lesser degree than fluoride varnish (sodium fluoride). Conclusion: Bovine teeth immersed in olive oil for 6 h resist the erosive effect of citric acid exposure for 15 min. Olive oil has less effect on the prevention of erosive tooth wear when compared to fluoride varnish.

Evaluation of Rremineralization Capacity of Non-fluoride Home Products

The aims of the study were to characterize enamel, dentine and cementum surface aspect after using non-fluoride remineralization toothpastes containing calcium carbonate and calcium glycerophosphate by SEM evaluation, to determine chemical composition of enamel, dentin and cement after remineralization products application by EDX assessment, and to compare the remineralization capacity of the tested products. Ten extracted teeth having no dental caries, erosive or wear lesions were selected for the study. The teeth were split bucco-lingually and mesio-distally in four pieces. A free window of enamel, dentine, and cementum (4X4 mm) in the cervical area of the slices was preserved. In control group the slices were subjected to a artificial caries lesion formation. In study groups EcoBio� (President Company), Bio-natural (Dentissimo, Swiss Biodent), and Arthrodont Cassic (Pierre Fabre Oral Care) toothpastes were applied two times a day, for 3 minutes during caries lesion formation. The surface topography has been analyzed using a scanning electron microscope and the quantitative and qualitative chemical composition has been evaluated using an EDX detector. Interprismatic and intraprismatic mineral loss is clearly visible at higher magnification in enamel samples in control group. Some areas of demineralization are still present, and also small areas of extern deposits are visible on enamel, dentine and cementum samples in the groups were tested products were applied. All the tested toothpastes increased calcium and phosphorous ion concentrations in enamel, dentine and cementum. The highest remineralization effect was recorded in enamel by Dentissiomo, followed by Arthrodent and EcoBio toothpastes. In dentine and cementum the highest remineralization effect was registered by Arthrodent, followed by Dentissiomo and EcoBio toothpastes.

Effectiveness of polyacrylic acid-bioactive glass air abrasion preconditioning with NovaMin remineralization on the microhardness of incipient enamel-like lesion.

Background:Bioactive glass (BAG) remineralization is a promising method for dental hard tissue regeneration. The aim of this study was to evaluate the microhardness of incipient enamel-like lesions with or without preconditioning by air abrasion using polyacrylic acid (PAA)-BAG before application of NovaMin remineralizing agent.Materials and Methods:Forty extracted human molars were selected, sectioned mesiodistally obtaining buccal and lingual halves, and embedded in resin molds. Specimens were randomly assigned to four groups (n = 10) according to the remineralization protocol: G1 (control, artificial saliva), G2 (preconditioning), G3 (NovaMin), and G4 (preconditioning and NovaMin). Enamel windows 4 mm × 4 mm were done on the buccal and lingual surfaces. Specimens were immersed in a daily renewed demineralizing solution to create white spot lesions. Remineralizing agents were applied according to the manufacturer's instructions, and specimens were stored in a daily renewed artificial saliva. Microhardness was assessed using Vickers hardness number (VHN) at baseline (positive control), after demineralization (negative control), and after 24-h and 1-month remineralization.Results:The preconditioning/NovaMin group after 1 month showed a statistically significant high VHN, with no statistically significant difference between it and the positive control. This was followed by the NovaMin group after 1 month, while the lowest VHN was found in the demineralized group, with no statistically significant difference between it and the preconditioning group, whether after 24 h or 1 month.Conclusions:Enamel preconditioning with PAA-BAG air abrasion play a major role in enhancement of remineralization when it is accompanied with NovaMin. Furthermore, an extended period of time had helped to attain more benefits from NovaMin remineralization.Clinical Significance:Enamel remineralization with NovaMin after conditioning by bioactive glass air abrasion, provides the patients with a fast and durable treatment of incipient enamel lesions, which would reduce the possibility of future progression of demineralization and caries occurrence.

Effects of citric acid modified with fluoride, nano-hydroxyapatite and casein on eroded enamel

ObjectivesThe aim of this in vitro study was to evaluate the effects of citric acid containing fluoride, nano-hydroxyapatite, and casein on eroded enamel. DesignThe crowns of 120 extracted bovine incisors were embedded in acrylic resin. An enamel window (2 × 3 mm) was created on the surface. Before in vitro pellicle formation samples were eroded in 1% citric acid (pH = 3.2) for 1 h at 36 °C and were randomly classified to eight groups (n = 15) as follows: Positive control: 1% citric acid, Negative control: Distilled water, F1: 0.047 mmol/L sodium fluoride, F2: 0.071 mmol/L sodium fluoride, NHA1: %0.05 Nano-Hydroxyapatite, NHA2: %0.1 Nano-Hydroxyapatite, C1: %0.02 Casein, C2: %0.2 Casein. Erosion cycling was performed three times daily for 3 days. In each cycle, the samples were immersed in 10 mL of control or modified solutions (10 min) and in 10 mL of artificial saliva (60 min). The surface roughness and enamel loss were analyzed by using profilometer, scanning electron microscopy (SEM) and atomic force microscopy techniques (AFM). ResultsAmong the groups, the positive control group was found to be having the highest erosive wear. Erosive wear in the F2, NHA2, C1, and C2 groups was not significantly different from the negative control group (p > 0.05). The C1 and C2 groups showed that erosion terminated and minimal tissue recovery occurred on the enamel surface. ConclusionAlthough all modifications reduced further demineralization, the citric acid modification with casein was found to be having a greater impact on dental erosion than the others.

Reliability and validity of FluoreCam for white-spot lesion detection: An in vitro study.

In the present study, we tested the reliability and validity of a new light fluorescence device, the FluoreCam. Twenty-five human teeth were sectioned mesiodistally into halves. Group 1 (n=30) included specimens with either sound enamel or natural white-spot lesions (WSL). Group 2 (n=20) included specimens with sound enamel used to create artificial WSL. Using the FluoreCam, baseline scans of enamel surfaces were obtained under standardized conditions. Group1 was scanned again the next day. Group 2 specimens were covered with an acid-resistant nail polish, leaving a 2×6-mm enamel window exposed, immersed in Queiroz-solution (64hours, 37°C/pH5 with agitation), and then scanned again. Random error of the repeated measurements (reliability) was determined using method errors and intraclass correlations (ICC). Systematic error and the ability to detect demineralization (validity) were tested using Wilcoxon signed-rank test. Method errors for Group 1 replicates were .39mm2 (area), .72 pixels (intensity), and 5.69 pixels.mm2 (impact). Group 2 method errors were consistently slightly higher than those of group 1. FluoreCam showed highly reliable measurements for group 1 (ICC: 0.93-0.98) and group 2 (ICC: 0.87-0.97). There were no statistically-significant systematic errors for either group (P>.05). In group 2, enamel demineralization was statistically significant in area (P<.001), intensity (P=.001), and impact (P<.001). FluoreCam is highly reliable and valid for in vitro assessments of enamel demineralization.

Comparative study of two chemical protocols for creating white spot lesions: An in vitro FluoreCam evaluation.

The aim of the present study was to compare the effectiveness and practicality of two commonly-used protocols for white spot lesion creation. Sound posterior human teeth were sectioned into halves and randomly allocated into two groups (n=20). Using the FluoreCam system, the enamel surfaces were imaged under standardized conditions, and baseline data (area, intensity, and impact) were recorded. Specimens were covered with an acid-resistant polish, leaving a 2×6-mm enamel window. Group 1 was immersed in Queiroz solution (64hours/37°C/pH5 with agitation); Group 2 was immersed in Buskes solution (14days/37°C/pH5 with agitation). The specimens then were imaged again. Within-group changes that occurred over time were evaluated using the Wilcoxon signed-rank test. Between-group differences were analyzed using the Mann-Whitney U-test. Polarized light microscopy (PLM) was used to calculate the mean lesion depth of representative specimens. Each protocol showed significant changes in the surface area, intensity and impact of demineralization over time (P<.05). There were no statistically-significant differences (P=.53, P=.2, P=.74) between the two groups. PLM showed that the mean lesion depths of representative specimens were 51.4 and 73.0μm for groups 1 and 2, respectively. While both protocols produce similar amounts of demineralization, the Queiroz solution is more practical, as it requires less time.

Does erosion progress differently on teeth already presenting clinical signs of erosive tooth wear than on sound teeth? An in vitro pilot trial

BackgroundErosive tooth wear (ETW) is clinically characterized by a loss of tooth surface, and different enamel depths may have different susceptibility to demineralization. Therefore, the aim of this in vitro pilot study was to assess if the progression of erosive demineralization is faster on teeth already presenting signs of ETW when compared to originally sound teeth.MethodsWe selected 23 central incisors: 14 were clinically sound (Sound) and 9 presented clinical signs of early erosive tooth wear (ETW-teeth). The teeth were embedded in resin, leaving an uncovered window of native enamel (6.69 ± 2.30 mm2) on the incisal half of the labial surface. We measured enamel surface reflection intensity (SRI) initially and after each consecutive erosive challenge (1 % citric acid, total of 4, 8, 12, 16, 20 and 24 min). Calcium released to the citric acid was measured with an atomic absorption spectrometer.ResultsWe observed higher initial SRI values in ETW-teeth than in Sound teeth (p = 0.007). During in vitro erosive demineralization, we observed that erosion on originally Sound teeth progressed significantly slower (p = 0.033) than on ETW-teeth: SRI decreased by 75 % (from 100 to 25 %) on Sound teeth, and by 89 % (from 100 to 11 %) on ETW-teeth. Calcium release increased during erosion, but presented no significant differences (p = 0.643) between originally Sound (0.031 μmol/mm2) and ETW-teeth (0.032 μmol/mm2). There was satisfactory correlation between calcium release and rSRI values (rs = −0.66).ConclusionThe optical reflectometer distinguished originally sound teeth from those with signs of ETW, and the results suggest that acid demineralization progresses differently on teeth already presenting clinical signs of ETW than on sound teeth.

The Micrograph Image of Early Experimental Dental Caries in Permanent Teeth in Hanoi Medical University

Objectives: This reseach aimed to describe micrograph images of experimental carious lesions at early stage. Method: Experimental study . 60 permanent extracted premolars (patient aged 18-25) were cleaned and removed remaining soft tissue. Each tooth was painted with acid-resistant coating leaving an enamel window of approximately 1 × 1 mm 2 in buccal surface. After 96 hours being soaked in demineralization solution to create artificial carious lesion, the coating was removed, and all teeth would be evaluated using ICDAS criteria and made tooth specimens to be observed under a scanning electronic microscope (SEM). Results: After being soaked in demineralization solution, the carious lesion gained was at stage ICDAS 1 with 66.7% ; and 33.3% at stage 2. Mean depth and area of the lesions was 107.6 µm and 1.14 µm 2 , respectively. The difference in depth and area of lesions between group ICDAS 1 va ICDAS 2 was significantly statistical with p=0.0001. Micrograph images showed that after being soaked in demineralization solution, enamel surface became rough, enamel rods lost minerals in the body more than in the sheath, cross-sectional images showed widened gaps between the rods due to demineralization. There was a difference in demineralization degree between group ICDAS 1 and 2. Conclusion: Image of cariouslesions gained after being soaked in demineralization solution showed that naturally carious and artificially carious -like lesions shared many similar characteristics due to theevaluation based on ICDAS criteria for detecting early carious lesions and scanning electronic microscope. DOI: 10.14693/jdi.v23i1.973

Evaluation of the effectiveness of low power diode laser with different wavelengths in dental caries prevention

Objectives: To investigate the effectiveness of low power diode lasers, with different wavelengths and different irradiation times in caries prevention an ex vivo study. Materials and Methods: True experimental posttest design on 130 extracted human premolar teeth by measuring caries-like lesions examined by polarized light electron microscope after irradiation by four low power diode lasers 532 nm (4 mW), 671 nm (100 mW), 675 nm (30 mW), and 810 nm (20 mW). A fifth group was added as a control (without irradiation). The specimens were prepared by coating the teeth with acid resistance nail varnish leaving uncovered 2 mm × 2 mm of the enamel surface mesially or distally below the contact area. For each wavelength, samples were divided into three groups for three irradiation time as 4, 8, and 12 min; each group consisted of 10 teeth. Irradiated samples and the control were immersed in lactic acid (4.8 pH) and incubated for 21 days under controlled temperature of 37°C and controlled PH of 4.8. After the incubation period, the teeth were sectioned longitudinally by dissecting the 2 × 2 enamel window and the depth of the lesion was measured microscopically. ANOVA test was used to compare between different wavelengths and different irradiation times with level of significant set at P ≤ 0.05. Results: The depth of the caries-like lesions in 810 nm and 675 nm was more than that in control group (180 μm), while statistical significant difference was found (P = 0.002); when the 671 nm and 532 nm lasers wavelengths revealed depth of 70 μm and 112 μm, respectively. Increasing irradiation time decreases the depth of caries-like lesions. Conclusion: Diode laser of wavelengths 532nm and 671 nm showed less depth than control group, indicating caries prevention effect. Increasing irradiation time to a certain value increases resistance to acid dissolution.