Enamel Surface Research Articles

Bacterial dynamics in the progression of caries to apical periodontitis in primary teeth of children with severe early childhood caries.

Early childhood caries (ECC) are a prevalent chronic disease in young children. However, there has been limited research on the microbiota in different tissue levels of the same tooth in children with ECC. This study aimed to investigate the dynamic changes in bacterial diversity during the progression of Severe Early Childhood Caries (S-ECC) within the same tooth, from the tooth surface to the root canal, by collecting tissue samples from different areas of the affected tooth. Twenty primary teeth with periapical periodontitis were selected from 20 children aged 3-5 years, with 100 samples collected from the different layers: uncavitated buccal enamel surface without white spot lesion (surface), the outermost layer of the dentin carious lesion (superficial), the inner layer of carious dentin (deep), necrotic pulp tissue (pulp), and root exudate (exudate). The taxonomy of each OTU representative sequence was analyzed against the 16S rRNA database. Comparisons of alpha diversity between groups were performed. The number of shared and unique genera between groups counted. Beta diversity was contrasted to evaluate differences in bacterial community composition, and the relationships between the microbiota and samples were analyzed. The heatmap analysis of the 30 most abundant genera was used, which highlighted their relative distribution and abundance. The significantly abundant taxa (phylum to genera) of bacteria among the different groups were identified. The differences of relative abundance between bacterial genera among the five groups were analyzed. Significant Spearman correlations were noted, and visualization of the co-occurrence network was conducted. Bacterial 16S rRNA gene sequencing showed that most genera were present in all layers, with the number of shared genera increasing as the disease advanced. The bacterial communities and core genera in the co-occurrence network changed with progression to severe ECC. An increase in both the quantity and complexity of bacterial interactions was observed. This study emphasized the importance of paying attention to the relationship between microbial species rather than just checking changes in bacterial species structure when investigating the role of bacteria in disease progression.

Esthetic rehabilitation of a patient with moderate fluorosis: a digital workflow

Dental fluorosis is considered as a worldwide dental health problem. Its prevalence is increasing in different parts of the world. It is described as a disorder of enamel development caused by chronic and excessive exposure to high concentrations of fluoride during the formation of enamel, which could be responsible for the hypermineralization of enamel increasing its porosity. It is clinically identified as white lines covering all or a part of the enamel surface. Posteruptively, these subsurface porosities may attract various extrinsic stains and /or bacteria and change the color of the affected enamel. In some cases, occlusal trauma may cause its detachment. The therapeutic management of dental fluorosis includes bleaching, microabrasion, veneering and crowning. The choice of the appropriate alternatives is closely linked to damages within the enamel matrix. Thylstrup-Fejerskov categorized these damages with severity scores based on their histological features. Mild-to-moderate fluorosis are often managed with bleaching and/or microabrasion, while severe fluorosis, is generally treated by veneering and crowning. The clinical case describes the treatment of discolored teeth with veneers using lithium disilicate-reinforced glass-ceramic material and highlights the different guidelines to optimize veneer bonding on fluorosis teeth.

Effect of treatment with phosphate, casein phosphopeptide and fluoride on the remineralization: in vitro study.

This study aimed to evaluate in vitro the effect protocols and anticaries agents containing casein amorphous calcium fluoride phosphopeptide-phosphate (CPP-ACPF, MI Paste Plus), sodium trimetaphosphate (TMP) and fluoride (F), in remineralization of caries lesions. Bovine enamel blocks with initial caries lesions were divided into groups (n = 12): 1) Toothpaste without F-TMP-MI Plus (Placebo); 2) Toothpaste 1100 ppm F (1100F), 3) 1100F + MI Paste Plus (1100F-MI Paste Plus), 4) Toothpaste with 1100F + Neutral gel with 4,500 ppm F + 5%TMP (1100F + Gel TMP) and 5) Toothpaste with 1100F + Neutral gel with 9,000 ppm F (1100F + Gel F). For the 4 and 5 groups the gel was applied only once for 1 minute, initially to the study. For the 3 group, after treatment with 1100F, MI Paste Plus was applied 2x/day for 3 minute. After pH cycling, the percentage of surface hardness recovery (%SHR); integrated loss of subsurface hardness (ΔKHN); profile and depth of the subsuperficial lesion (PLM); concentrations of F, calcium (Ca) and phosphorus (P) in enamel was determined. The data were analyzed by ANOVA (1-criterion) and Student-Newman-Keuls test (p < 0.001). Treatment with 1100F alone led to ~ 28% higher remineralization when compared to treatment with 1100F associated with MI Paste Plus (p < 0.001). The 1100F and 1100F + Gel F groups showed similar values for %SHR (p = 0.150). 1100F + Gel TMP treatment also remineralized the enamel surface by ~ 30% and 20% when compared to the 1100F + Gel F and 1100F groups (p < 0.001). The lower lesion depth (ΔKHN) was observed for the 1100F + Gel TMP group (p < 0.001), where it was 54% and 44% lower in comparison to the 1100F and 1100F + Gel F groups (p < 0.001). Polarized light microscopy photomicrographs showed subsurface lesions in all groups, but these lesions were present to a lower extent in the 1100F + Gel TMP group (p < 0.001). Treatment with 1100F + Gel TMP promoted an increase in the concentration of Ca in the enamel by ~ 57% and ~ 26% when compared to the 1100F and 1100F + MI Paste Plus groups (p < 0.001), respectively. There were no significant differences between the 1100F, 1100F + MI Paste Plus and 1100F + Gel F groups (p > 0.001). Similar values of P in the enamel were observed in the 1100F, 1100F + MI Paste Plus and 1100F + Gel F groups (p > 0.001), except for the 1100F + Gel TMP group, which presented a high concentration (p < 0.001). We conclude that the 1100F+TMP gel treatment/protocol led to a significant increased remineralization when compared to the other treatments/protocols and may be a promising strategy for patients with early caries lesions.

The Effects of Different Surface Preparation Techniques on Enamel Surface Properties and Bond Strength

The Effects of Different Surface Preparation Techniques on Enamel Surface Properties and Bond Strength

Effect of Resin Infiltration and Various Etching Techniques on the Bond Strength of Sound and Demineralized Enamel

Purpose: The objective was to assess the effect of various etching techniques on the shear bond strength(SBS) of resin infiltrated sound/ demineralized enamel. Materials and methods: A total of 180 extracted human upper incisors' enamel surfaces were utilized. Half of these specimens underwent artificial demineralization, which involved exposing to an acidic buffer with a pH of 4.8(14 days). The remaining half of the specimens were kept in their original sound condition. Subsequently, both the sound/ demineralized specimens were divided into 6 groups according to the presence (I)/absence (NI) of resin infiltrant and etching methods (35% phosphoric acid (PA), 9% hydrofluoric acid (HFA), and Er,Cr:YSGG laser(L) (n=15): Following different etching procedures, an etch-and-rinse adhesive system was used, before the application of a nanohybrid composite to the enamel surfaces. Then all specimens were submitted to SBS test (MPa). three-way ANOVA and Bonferroni test were used for statistical analysis(p=0.05). Results: PA showed the highest SBS in the I groups compared with L and HFA groups, both in demineralized and sound enamel (p&amp;lt;0.05). On sound enamel, L showed higher SBS than HFA (p&amp;lt;0.05). On demineralized enamel, L showed similar values with HFA(p&amp;gt;0.05). In the NI groups, L showed similar SBS to HFA on both demineralized and sound enamel(p&amp;gt;0.05). Conclusion:Resin-infiltrated enamel can be etched by 35% phosphoric acid without jeopardize bond strength.

Reliability of Automated Biometrics in the Analysis of Enamel Rod End Patterns- In Vitro Study

ABSTRACT: Introduction: Ameloglyphics is the study of the distinctive patterns found on the enamel surface of teeth, which are different on each tooth and particular to each person. The purpose of this study was to compare the enamel print patterns on the buccal and lingual surfaces of teeth to see if there are any appreciable differences, and to evaluate the sensitivity and reliability of an automated biometrics software. Method: The study involved 62 individuals including 36 females and 26 males, from age range 15-60 years. From each individual one tooth sample was analyzed using a light microscope to capture images of the buccal and lingual surfaces middle third. These images were then analyzed using biometric software called Source AFIS, which processed the images and displayed enamel patterns. Data were entered and analyzed using GPower software (version 3.0). Chi-square test and Goodness of fit tests were done to compare the enamel rod end patterns between the teeth surfaces These enamel patterns were classified according to the “Manjunath Classification”. Result: The study found that there were no notable distinctions in enamel print patterns when comparing the teeth buccal and lingual surfaces. All 62 samples analyzed showed a high degree of similarity in enamel print patterns on both surfaces. This finding suggests that the same developmental, environmental, and genetic factors likely influence the enamel print patterns on both surfaces of a tooth. Conclusion: The samples' high frequency of comparable sub-patterns on both the buccal and lingual surfaces suggests that they are very similar to one another. This implies that tooth prints may be a valuable tool for forensic personal identification, particularly in the area of forensic dentistry.

Estimation of Buffering Capacity of Saliva Among 17-21 Years Old Population After Probiotic Yogurt Consumption-A Clinical Trial

The buffering capacity of saliva is a crucial function that serves multiple purposes. The normal pH of saliva is 6.3, and the buffering capacity of saliva maintains it above 5.5, thereby preventing demineralization. In this study, we evaluate the buffering capacity of saliva post-consumption of normal and probiotic yogurt. Therefore, the study's objective was to estimate saliva's buffering capacity among the 17-21-year-old population post-probiotic yogurt and regular yogurt consumption. The buffering capacity of saliva was tested using the Ericsson method (1959), where 0.5 mL of saliva was mixed with 1.5 mL of 5 mmol/L HCl. The mixture was mixed aggressively, centrifuged for a minute, and allowed to stand for 10 minutes. The baseline mean salivary buffering capacity of plain yogurt was , and after 15 days, it decreased to , then it gradually increased to after 30 days of follow-up. The baseline mean salivary buffering capacity of probiotic yogurt was , and after 15 days, it increased to then it increased further to after 30 days of follow-up. Probiotic yogurt reduces the incidence of dental caries by preventing demineralization of the enamel surface caused by reduced pH levels (acidic pH). However, it is seen that the buffering capacity of saliva does not significantly increase after the consumption of probiotic yogurt as compared to regular yogurt.

The effect of Greek yogurt on the surface of bovine tooth enamel

The effect of Greek yogurt on the surface of bovine tooth enamel

Evaluation and Comparison of Thermal Changes in the Pulp Chamber in Different Inter Proximal Reduction Techniques: An In-vitro Study

Introduction: Interproximal reduction (IPR) is a common orthodontic treatment procedure that is used which involves tooth reduction, anatomic recontouring, and protecting permanent teeth proximal enamel surfaces. Sheridan described the air-rotor stripping technique as an alternative to extraction in borderline cases. Though there are many studies, it was not clearly differentiated regarding the pulpal temperature changes during IPR.&#x0D; Materials and Methods: In this in vitro study, 63 extracted human premolar teeth were randomly assigned to three groups (n=21). Group-1 (Strauss diamond stripping bur) at high speed above 20,000 rpm, Group-2 (Manual Handheld metal stripper). Group-3 (Strauss diamond stripping disc) at a low speed below 15,000 rpm. The average mean temperature is assessed for each tooth during various techniques using K-type thermocouple. During the procedure, the thermometer display was covered, and the temperature was revealed after all the stripping procedures had already been performed. Data were analyzed using IBM SPSS version 20 software. Descriptive statistics, one way analysis of variance with Tukey’s post hoc tests were done to analyze the study data.&#x0D; Results: The mean rise in temperature was highest with disc &amp; micromotor (4.3ºC) followed by airotor &amp; bur (4.02ºC) and manual method (2.52ºC) (p ≤ 0.05).&#x0D; Conclusion: There was an increase in the pulpal temperature using diamond stripping disc with micromotor followed by the airotor and bur, manual hand held stripping.

Assessment of surface roughness and compressive strength of resin-based composite using different types of bleaching protocols.

Background and objective: This study aimed to evaluate the effect of three types of bleaching protocols on the surface roughness and compressive strength of composite resin. Methods: Eighty composite resin samples were prepared using metal molds; forty samples (2 mm in height and 8 mm in diameter) for surface roughness evaluation and the other forty samples (6 mm in height and 4 mm in diameter) for compressive strength. Every forty samples were divided into four groups; Group 1 (n = 10) The samples were stored in deionized water at 37°C for two weeks as control, group 2 (n =10) The samples were subjected to bleaching with 22% Carbamide Peroxide (CP) Home bleaching, group 3 (n =10) The samples were subjected to bleaching with 14% Hydrogen Peroxide (HP) Home bleaching and group 4 (n =10) The samples were subjected to bleaching with 25% Hydrogen Peroxide (HP in-Office) in a dental clinic. After bleaching, groups 2, 3, and 4 were evaluated for surface roughness and compressive strength. Results: The enamel surface roughness of all specimens were increased after bleaching protocols to a very similar extent with no statistically significant difference between the means of enamel roughness of the control group and the other three groups and the highest value was recorded in the Carbamide Peroxide group (CP), while compressive strength of the composite was decreased after using bleaching protocols in all groups in comparison with the control group and the least compressive strength was recorded in (HP) group followed by (HP in-Office) group and (CP) group respectively. Conclusions: Within the limitation of this study, the following conclusions can be drawn: There was a decrease in surface roughness using different types of bleaching protocols (22% CP and 14% HP) at-Home bleaching technique and (25%) in-Office HP bleaching. Although there was no significant difference between them. The compressive strength of the composite resin was reduced after bleaching with no significant difference. Keywords: Bleaching protocol, Hydrogen peroxide, Carbamide peroxide

Fluoride - a scoping review for Nordic Nutrition Recommendations 2023.

Fluoride has a well-documented role in the prevention and treatment of dental caries, but the mechanism is attributed to local effects on the tooth enamel surface rather than systemic effects. Fluoride is not considered essential for humans, no deficiencies are known, and no optimal range, which will not result in moderate fluorosis in some individuals, can be set. Recently, research studies have shown evidence for a relationship between fluoride intake and cognitive outcomes and interaction with iodine nutrition, but the evidence is weak so more data are warranted. For performing longitudinal cohort studies in the Nordic and Baltic region, data on fluoride in food and beverages need to be implemented in food composition tables. As the preventive effects of fluoride are mainly from topical treatment, monitoring of fluoride intake and establishing reference values for fluoride in urine and plasma are warranted to establish safe intake values.

Comparison of the Remineralization Effect of Nano Herbal Toothpaste With Two Kinds of Toothpaste Containing Fluoride and Bioactive Glass on Primary Enamel Lesions: An In Vitro Study

Background: Considering the therapeutic properties of the compounds used in Albodent Iranian toothpaste and little evidence about the effect of NovaMin toothpaste on primary caries lesions, the purpose of this research was to compare the effect of toothpaste containing fluoride and toothpaste containing bioactive glass with Albodent toothpaste on enamel remineralization in a laboratory manner. Methods: Overall, 24 healthy human premolar teeth were selected and divided into buccal and lingual halves. The demineralization cycle of the samples was performed for 14 days. The samples were classified into four groups and were brushed twice a day for 28 days with tested toothpaste. A microhardness test was conducted, and changes in the enamel surface and morphology of one sample selected from each group were evaluated by scanning electron microscopy. The analysis of variance and Tukey’s tests were used for the statistical analysis of the data. Results: The average difference in microhardness in the studied groups was statistically significant (P&lt;0.05) when compared two-by-two with the control group. The most noticeable difference was found in the comparison of the Sensodyne group with the control group, while the lowest difference was observed in the comparison of the Albodent group with the control group. Conclusion: The presence of NovaMin in toothpaste along with fluoride can increase the efficiency of the remineralization rate of primary enamel lesions compared to fluoride toothpaste without bioactive glass. In addition, the effectiveness of herbal toothpastes, which do not contain essential artificial ingredients in the remineralization of primary enamel lesions was lower than that of non-herbal fluoride toothpastes.

Remineralization potential of strontium-doped nano-hydroxyapatite dentifrice and casein phosphopeptide-amorphous calcium phosphate cream on white spot lesions in enamel following orthodontic debonding - a randomized controlled trial.

This study was intended to compare and determine the potency of strontium-doped nano-hydroxyapatite paste against a topical cream containing casein phosphopeptide-amorphous calcium phosphate and a regular dentifrice for remineralization of white spot lesions of enamel following orthodontic debonding. Ninety individuals with white spot lesions on their enamel who visited the orthodontic department for de-bonding were selected for the research. Patients were randomly assigned to three distinct groups with each group consisting of 30 patients. Group 1 served as the control and received regular dentifrice, Group 2 received strontium-doped nano-hydroxyapatite paste, and Group 3 received casein phosphopeptide-amorphous calcium phosphate topical cream. Patients were instructed to locally apply a specified amount of the prescribed preparation twice daily for six weeks. The data were analysed using the statistical programme SPSS 22.0 (SPSS Inc., Chicago, IL, USA), and the level of significance had been set at p < 0.05. Group 1 did not show any change in the enamel following the application of toothpaste. Both Group 2 and 3 demonstrated higher post-treatment scores, indicating effective remineralization potential (p < 0.001). However, Group 2 (strontium-doped nano-hydroxyapatite paste) displayed significantly greater remineralization capacity when compared to group 3 (casein phosphopeptide-amorphous calcium phosphate topical cream). Compared to conventional dentifrice and casein phosphopeptide-amorphous calcium phosphate paste, strontium-doped nano-hydroxyapatite preparation demonstrated greater enamel remineralization of the white spot lesions and favourable surface alterations in the enamel surface. strontium-doped nano-hydroxyapatite can be utilised safely and efficiently to treat early caries and remineralise white spot lesions on the enamel.

Pengaruh Pasta Gigi Ekstrak Strawberry (Fragaria x ananassa) dan Pasta Gigi Whitening Terhadap Diskolorasi Akibat Minuman Kopi Robusta

Background: Tooth discoloration is a change in the colour of the teeth that can damage aesthetics and can affect a person’s confidence. Coffee is one of the factors causing extrinsic discoloration. The content of caffeine and tannins in coffee can affect the colour to be more yellow. One of toothpastes that can be used to remove stain is whitening toothpaste. The abrasive power contained in whitening toothpaste affects decrease in thickness of enamel surface. Natural ingredients are needed as an alternative, such as strawberries. Strawberries contain elegatic acid and malic acid which can whiten teeth. Objective: The aim of this study is to determine the effect of strawberry extract toothpaste and whitening toothpaste on discoloration caused by robusta coffee drink. Method: This type of research is true experimental laboratory with pre-test and post-test design. 36 samples of post-extraction premolars according to the inclusion criteria were immersed in coffee for 7 days and the initial colour was measured with colorlfex ez spectrophotometer. Samples were divided into 2 groups, group 1: brushing teeth with strawberry extract toothpaste and group 2: brushing teeth with whitening toothpaste for 3 minutes twice a day for 14 days. Final colour measurement with colorlfex ez spectrophotometer. Results: Data analysis using paired t-test with the results in strawberry extract toothpaste group and whitening toothpaste group showed a significant difference before and after treatment with p=0. Conclusion: There is an effect between strawberry extract toothpaste and whitening toothpaste in brightening teeth that are discolorated due to robusta coffee drink.

Topographical Analysis of Human Enamel after Phosphoric Acid Etching and Er,Cr:YSGG Laser Irradiation.

Introduction: Dental hard and soft tissues have been successfully removed by using the Er,Cr:YSGG laser, but there is a controversy about using lasers over conventional tooth surface preparation for bonding aesthetic restoration. Surface roughness and wettability in response to Er,Cr:YSGG laser irradiation are essential properties for restoration longevity. Methods: Fifty-one intact human premolars removed in orthodontic treatment were included in this study and divided into three groups (n=17). The first group (G1) was the control without surface treatment, (G2) was treated with 37% phosphoric acid for 15 seconds, and (G3) was treated with the Er,Cr:YSGG laser using the following parameters: 2 W or 3 W at 20 Hz, 10% air and water ratio using the MZ6 laser tip. The standardization of laser irradiation was accomplished by a computerized numerical control unit. The surface of the samples was evaluated by using a light microscope, profilometer, atomic force microscopy (AFM), SEM, and wettability tests. Results: The SEM examination revealed that the lased enamel surface was clean, irregular, and devoid of a smear layer, while the acid etch surface was relatively smooth and covered with a smear layer. The surface roughness of the lased enamel surface was significantly higher than that of other groups, according to the results of the profilometer as well as the AFM tests. The wettability test showed that the lased enamel surface recorded a significant reduction in the contact angle in comparison to the other groups. Conclusion: It can be concluded that the Er,Cr:YSGG laser can be used as an alternative and safe method to the acid-etching technique for surface treatment.

Orthodontic Bracket Rebonding with and without Fluoride: A Pilot Study

Adhesion between orthodontic brackets and conditioned enamel surfaces is essential for treatment success with fixed appliances. During treatment, enamel demineralization lesions commonly appear although remineralization is possible through fluoride application. Aim: Evaluation of the surface rugosity in bracket rebonding, specifically the influence of fluoride application before the bonding protocol. In total, 30 human premolars extracted for orthodontic reasons were used and divided into three groups. The control group was not submitted to any experimental manipulation; group 1 and 2 were placed in a demineralization solution and group 2 was additionally subjected to a subsequent fluoride application. The surface rugosity was measured at different timings: T0—before bracket bonding; T1—first bracket debonding after composite removal; and T2—second bracket debonding after composite removal. For the statistical analysis, the Kruskal–Wallis test, Mann-Whitney test, and Student’s t-test were used. Regarding the comparison between groups, at T0 and T1, no statistically significant differences were observed. However, at T2, statistically significant differences were verified between the control group and group 1 for the parameters: Ra (p = 0.0043), Rq (p = 0.0043), Rqmax (p = 0.0043), Rp (p = 0.0087), and Rv (p = 0.026). Regarding the evaluation between time points, in the control group, no statistically significant differences were observed. In group 1, statistically significant results were found between T0 and T1 for the parameters: Rq (p = 0.0451), Rqmax (p = 0.0451), Rp (p = 0.0091), and Rvk (p = 0.0433) and between T1 and T2 for the parameters: Ra (p = 0.0465), Rq (p = 0.0433), Rqmax (p = 0.0433), and Rp (p = 0.0155). In group 2, statistically significant differences were found between T0 and T1 for the parameter Rvk (p = 0.0405). A decrease In surface rugosity was observed during multiple bracket rebonding procedures. Therefore, this study suggests that rebonding procedures alter the enamel surface rugosity. The need for rebonding should be avoided, opting for a more effective and correct first bonding. In the case of multiple rebonding, enamel remineralization maneuvers must be applied to recover the surface, since the results of this study suggest that the application of fluoride prior to bracket adhesion promotes lower surface roughness.

Shear bond strength between standard or modified zirconia surfaces and two resin cements incorporating or not 10-MDP in their matrix

ObjectiveThis study aimed first to compare the shear bond strength between zirconia samples luted to enamel with a 10-MDP- containing resin cement (Panavia F2.0, Kuraray, Japan) and those luted with a resin cement using a separated 10-MDP monomer-containing bottle (Panavia V5, Kuraray, Japan). The second objective was to evaluate the bond stability after 150 days of aging in water, between enamel and zirconia ceramic surface enhanced with a glass-ceramic coating. Materials and methods80 specimens composed of ceramic cylinders and enamel disks were obtained, within eight experimental groups (n = 10). 60 zirconia cylinders (Katana STML zirconia, Kuraray, Japan) were assigned to 3 groups according to their surface treatment: milled/sintered surface (ZRCT), tribochemical silica-coating (Cojet™ Sand, 3 M ESPE, Seefeld, Germany) (ZRTC), and glass-ceramic coating (IPS e.max Zirpress) (ZRZP). 20 cylinders of lithium disilicate had a milled surface (IPS e.max CAD, Ivoclar-Vivadent, Schaan, Liechtenstein) (ECAD). The cylinders of each group were further divided into two subgroups according to the resin cement used: Panavia F2.0 (-PF) and Panavia V5 (-PV). All specimens were stored in distilled water for 150 days before shear bond strength (SBS) tests. The fracture mode was analyzed, and data were statistically computed (two-way ANOVA, post hoc Tukey test, p < 0.05, SPSS, IBM, v26). ResultsThe ECAD-PF group recorded the highest SBS values (31.75 ± 2.2), and the ZRCT-PF group recorded the lowest values (5.59 ± 1.1). The two-way ANOVA test showed that ceramic surface treatment had a statistically significant effect on SBS (F (3,72) = 38.95, p < 0.001) while the type of ARC did not (F (1,72) = 2.40, p = 0.126). Tukey’s post hoc test revealed no statistical difference between the ZRZP and the ZRTC or ECAD groups. ConclusionWithin the limitations of this study, the PV resin achieved similar shear bond strength results between tribocoated zirconia and enamel compared to the one for glass-ceramic and enamel. Furthermore, a long-term durable bond, similar to the glass-ceramic one, was achieved with the heat pressed ceramic coated specimens. Thus, this new surface treatment could be recommended for anterior cantilever bridges for its fracture resistance and bonding ability.

Bleached enamel reversal using grape seed extract, green tea, curcumin-activated photodynamic therapy, and Er: YAG on microleakage and bond integrity of composite material bonded to the enamel surface

AimsBleached enamel reversal using antioxidants sodium ascorbate (SA), Green tea extract (GTE), grape seed extract (GSE), Curcumin photosensitizer (CP) and Er: YAG laser on the adhesive strength and marginal leakage of composite material bonded to the bleached enamel surface. Materials and methodsEnamel surface of hundred and twenty sound human first premolar teeth was cleansed using pumice and bleached with 35 % hydrogen peroxide. The samples were randomly divided into 5 groups based on the antioxidants used. n = 20 Group 1 (Control): No antioxidant agent, Group 2: 10 % SA solution, Group 3: 6.5 % GSE, Group 4: 5 % GTE, Group 5: Er: YAG laser and Group 6: CP. Following reversal, the composite was built and cured for 40 s. All the specimens were stored in distilled water at room temperature for 1 day. Microleakage, SBS, and failure mode were analyzed. Kolmogorov-Smirnov test, one-way analysis of variance, and Tukey's multiple post hoc test were used to analyze the data statistically. ResultsGroup 2 (SA) (20.11 ± 5.79 nm) exhibited minimum value of microleakage and highest SBS (10.22 ± 1.62 MPa). Whereas, Group 1 (No antioxidant agent) displayed maximum scores of marginal leakage (28.11±8.89 nm) and lowest SBS (7.02 ± 1.22 MPa). ConclusionCP, GTE and GSE can be used as a potential alternative to the commonly used SA solution to reverse the negative impact of bleaching on the enamel surface. The use of reversal agents CP, GTE and GSE improves bond values with a decrease in microleakage scores However, future studies are still warranted to conclude the outcomes of the existing study.

Xylitol associated or not with fluoride: Is the action the same on de- and remineralization?

ObjectivesThis study evaluated the effect of xylitol combined or not with fluoride (F) on reduction of demineralization and increase of remineralization of shallow and deep artificial enamel lesions. MethodsBovine enamel samples were allocated to the following solutions groups: no xylitol (negative control), 5% xylitol, 10% xylitol, 20% xylitol, 500 ppm F (as NaF), 5% xylitol+F, 10% xylitol+F or 20% xylitol+F (n = 12–15). For the demin study, a pH-cycling model (demineralization-6 h, pH 4.7/remineralization 18 h, pH 7.0) was employed for 7 days. Treatments were applied 2 × 1 min. In the remin study, specimens were pre-demineralized for 2, 5 or 10 days. Afterwards, a pH-cycling protocol was conducted (2 h demineralizing and 22 h remineralizing solution/day for 8 days) and the same treatments were done. The response variables were percentage surface hardness loss (%SHL) and transverse microradiography. Data were analyzed by RM ANOVA/Tukey or Kruskal-Wallis/Dunn (p < 0.05) ResultsF and Xylitol combined with F reduced the %SHL (23–30%) compared to the negative control (61.5%). The integrated mineral loss and the lesion depth were not reduced by any treatment. Surface hardness recovery was seen only for shallow lesions in case of 20% xylitol+F compared to negative control. No lesion depth recovery, but significant mineral recovery was seen for F (2-days and 10-days lesion). ConclusionsAll concentrations of xylitol+F reduced enamel surface demineralization, while only 20% xylitol+F improved surface remineralization of shallow lesions in vitro. Clinical significanceOur results suggest that while F or any concentration of xylitol + F reduces surface demineralization, only 20% xylitol+F improves surface remineralization of shallow lesions in vitro. Therefore, xylitol may be added into oral products, combined to F, to control dental caries.

A new role for resveratrol: Protection of enamel against erosion

ObjectiveThe aim of this study was to determine the effect of different concentrations of resveratrol in protecting enamel against initial dental erosion in vitro. MethodsNinety bovine enamel samples (4 × 4 mm) were divided into six groups: Phosphate buffered saline (negative control; PBS), Commercial solution (Elmex Erosion Protection™; positive control) and resveratrol at 4 different concentrations (1, 10, 100 or 400 µg/mL). Initially, the samples were incubated in saliva for the formation of the acquired pellicle (250 µL, 1 h, 37 °C, 250 rpm). Afterward, the samples were incubated in the respective treatments (250 µL, 1 min, 37 °C, 250 rpm) and then reincubated in saliva (250 µL, 1 h, 37 °C, 250 rpm). Finally, the samples were subjected to an erosive challenge by incubating in 1 % citric acid (1 mL, pH 3.5, 1 min, 25 °C, 250 rpm). The percentage surface microhardness change (% SMC) was assessed using a microhardness tester. Data were analyzed by Kruskal-Wallis and Dunn's tests (p < 0.05). ResultsThe treatments with Elmex™ and resveratrol (1, 10 and 100 µg/mL) significantly protected enamel compared to the negative control, without significant differences among them. However, the group treated with the highest resveratrol concentration (400 µg/mL) did not show a significant difference from the negative control. ConclusionsResveratrol at concentrations ranging from 1 to 100 µg/ml was effective in preventing loss of enamel surface microhardness. Clinical significanceThis result suggests a potential new direction for the development of dental products based on resveratrol for the prevention of dental erosion.