Effect of Toothpaste Fluoride Concentration on Color Stability of Resin Composites: An In Vitro Study

ABSTRACT Objective: To investigate the effects of two different dentifrice fluoride concentrations on the color stability of the composite. Material and Methods: Twenty-seven specimens (2×4×5 mm) each of microfilled (Gradia, GC, Japan) and nanohybrid (Grandio, VOCO, Germany) composites were prepared. The specimens were randomly divided into six groups (control, Fluoflor caries protection toothpaste with 1450ppm Fluoride (EXW, France), and Fluoflor kids toothpaste with 500ppm Fluoride (EXW, France) (n = 9). The specimens were immersed in a mixture of artificial saliva and toothpaste in a ratio of 1:3 and applied for 60 seconds every 12 hours for 42 days. The control samples were incubated in artificial saliva at 37°C. Primary and secondary color measurements were performed using color parameters (L∗a∗b) with a spectrophotoshade (MHT Optic Research AG, Niederhasli, Switzerland). Data were analyzed using a two-way analysis of variance at a significance level of 0.05. Results: According to the two-way ANOVA analysis, there was no significant difference in color change between the composites and no difference in the level of discoloration between different fluoride concentrations(p>0.05). Also, None of the dentifrices caused clinically significant color changes(∆E˂3.3). Conclusion: No clinically unacceptable color changes were observed in the microfilled and nanofilled composites with different concentrations of fluoride toothpaste.

Development and Validation of an Educational Comic Book for Guidance on the Safe Use of Fluoride Toothpaste by Children

ABSTRACT Objective: To describe the elaboration and content validation of a comic book for guidance on the safe use of fluoride toothpaste by children. Material and Methods: Study on the development of educational technology carried out in four phases: 1 - literature review and script; 2 - elaboration of the material (illustrations, layout and design), 3 - validation (Content Validity Index = CVI and Flesch Readability Index = FI), 4 - pilot test to legitimize the material with the target population. Thirty-one individuals participated in the validation, being 07 expert judges and 24 representatives of the lay population, responsible for the daily care of preschool and school-age children. Results: In the validation, CVI= 0.97 (97%), indicating high agreement of the judges' answers; and FI = 92%, which corresponds to "very easy to understand" reading. In the pilot test carried out with the lay population, the 3 assessment blocks had CVI=1.0 (100%). Conclusion: The comic book proved to be valid regarding appearance and content and can be used for health education activities for adults on the use of fluoride toothpaste for oral hygiene in children.

Efficacy of 30% and 38% Silver Diamine Fluoride in Arresting Caries Lesions After Different Application Times: An in Vitro Study

Abstract Objective: To evaluate the efficacy of silver diamine fluoride (SDF) in arresting dentin caries lesions when applied under different concentrations and times. Material and Methods: Forty-two bovine blocks were selected and fixed in 24-well plates. Each well received a mixed bacterial inoculum added to the culture medium with 5% sucrose. The plates were incubated in microaerophilia (7 days) for caries formation, confirmed by micro-CT (M1). SDF was applied over the carious lesions for different times and concentrations (n=6): SDF 30% - immediate removal, 1 minute and 3 minutes; SDF 38%, - immediate removal, 1 minute and 3 minutes. The group without treatment was the control. Then, the samples were again scanned by micro-CT (M2) and submitted to a second cariogenic challenge for 21 days. Then, a final scan was performed (M3). Results: Mean pH at the culture medium and lesion depth were compared using Kruskal-Wallis and Wilcoxon tests. 38% SDF showed the lowest metabolic activity of the biofilm. All 38% groups and 30% 1 and 3 minutes did not show an increase in mean lesion depth comparing M3 with M1. However, only 30% 3 minutes and 38% 1 and 3 minutes showed a significant reduction of lesion depth. Conclusion: The minimum application time of 30% SDF to arrest dentin caries lesion was 1 minute, while 38% SDF arrested with application and immediate removal.

Evaluation of physical and biological properties of conventional glass ionomer cements / Avaliação das propriedades físicas e biológicas de cimentos de ionômero de vidro convencionais

Objetivo: avaliar as propriedades físicas e biológicas dos cimentos de ionômero de vidro convencionais (CIVs). Metodologia: foram avaliados os seguintes CIVs: Fuji IX (GC Europe, Bélgica), Ketac Molar (3M ESPE, Estados Unidos), Maxxion R (FGM, Brasil) e Vitro Molar (Nova DFL, Brasil). O tempo de presa, a alteração dimensional, a radiopacidade, a sorção e a solubilidade em água foram avaliados para todos os materiais. A resistência à compressão foi analisada em intervalos de 1h, 24h, 7 dias e 28 dias; e liberação de íons fluoreto em 3h, 24h e 72h. A viabilidade celular foi avaliada após 24 e 48 horas com células de fibroblastos. A análise estatística foi realizada por meio do software SigmaPlot 12 (Systat Inc, San Jose, CA, EUA), com nível de significância estabelecido em α = 0,05. Resultado: apenas o Fuji IX teve um tempo de presa dentro da faixa recomendada pela Especificação Padrão da ADA 96 (2012), não superior a 6 minutos. Vitro Molar e Maxxion R apresentaram radiopacidade que não estava de acordo com a especificação ADA 96 (2012). Maxxion R e Vitro Molar mostraram uma alteração dimensional estatisticamente semelhante. Quanto às propriedades mecânicas, o Fuji IX foi o único CIV que apresentou aumento da resistência à compressão durante o período de avaliação de 28 dias. O Ketac Molar apresentou a maior viabilidade celular, enquanto o Maxxion R apresentou citotoxicidade severa e o maior valor cumulativo de liberação de flúor. Conclusão: Fuji IX e Ketac Molar apresentaram as propriedades físicas e biológicas mais adequadas entre os CIVs avaliados.(AU)

Objective: to evaluate the physical and biological properties of conventional glass ionomer cements (GICs). Methodology: the following GICs were evaluated: Fuji IX (GC Europe, Belgium), Ketac Molar (3M ESPE, United States), Maxxion R (FGM, Brazil) and Vitro Molar (Nova DFL, Brazil). Setting time, dimensional change, radiopacity, water solubility and water absorption were evaluated for all materials. Compressive strength was analyzed after intervals of 1h, 24h, 7 days and 28 days; and release of fluoride ions at 3 am, 24 am and 72 am. Cell viability was assessed after 24 and 48 hours with fibroblast cells. Statistical analysis was performed using SigmaPlot 12 software (Systat Inc, San Jose, CA, USA), with a significance level set at α = 0.05. Result: only the Fuji IX had an adjustment time within the range recommended by the Standard Specification of ADA 96 (2012) of not exceeding 6 minutes. Vitro Molar and Maxxion R had radiopacity that was not in accordance with the ADA 96 (2012) specification. Maxxion R and Vitro Molar showed a statistically similar dimensional change. As for mechanical properties, Fuji IX was the only GIC that showed an increase in compressive strength during the evaluation period of 28 days. Ketac Molar showed the highest cell viability, while Maxxion R showed severe cytotoxicity and the highest cumulative fluoride release value. Conclusion: Fuji IX and Ketac Molar showed the most appropriate physical and biological properties among the evaluated GICs.(AU)

The effect of ionizing radiation on properties of fluoride-releasing restorative materials

Abstract The purpose of this study was to evaluate the effect of ionizing radiation from high energy X-ray on fluoride release, surface roughness, flexural strength, and surface chemical composition of the materials. The study groups comprised five different restorative materials: Beautifil II, GCP Glass Fill, Amalgomer CR, Zirconomer, and Fuji IX GP. Twenty disk-shaped specimens (8x2 mm) for fluoride release and 20 bar-shaped specimens (25 x 2x 2 mm) for flexural strength were prepared from each material. Each material group was divided into two subgroups: irradiated (IR) and non-irradiated (Non-IR). The specimens from IR groups were irradiated with 1.8 Gy/day for 39 days (total IR = 70.2 Gy). The amount of fluoride released into deionized water was measured using a fluoride ion-selective electrode and ion analyzer after 24 hours and on days 2, 3, 7, 15, 21, 28, 35, and 39 (n = 10). The flexural strength was evaluated using the three-point bending test (n = 10). After the period of measurement of fluoride release, seven specimens (n = 7) from each group were randomly selected to evaluate surface roughness using AFM and one specimen was randomly selected for the SEM and EDS analyses. Data were analyzed with two-way ANOVA and Tukey tests (p = 0.05). The irradiation significantly increased fluoride release and surface roughness for Amalgomer CR and Zirconomer groups (p < 0.05). No significant change in flexural strength of the materials was observed after irradiation (p > 0.05). The ionizing radiation altered the amount of fluoride release and surface roughness of only Amalgomer CR and Zirconomer. The effect could be related to the chemical compositions of materials.

Comparative Evaluation of Fluoride Release From Two Different Glass Ionomer Cement and a Novel Alkasite Restorative Material - An in Vitro Study

Abstract Objective: To compare the fluoride release from Conventional Glass Ionomer Cement (GIC), Resin Modified GIC (RMGIC), and Cention N Alkasite Material. Material and Methods: Forty- five disc-shaped specimens of three different restorative materials (Conventional GIC, RMGIC, and Alkasite material) were made and divided into 3 groups (n=15). Fluoride release was evaluated at the end of Day 1, 7, 14, and Day 28 using fluoride ion-selective electrode. Intergroup and Intra-group analysis was done using One-way ANOVA with a Post-hoc test. A p-value of <0.05 was considered statistically significant. Results: Cention showed more fluoride release (in parts per million) than GIC and RMGIC at increased time duration. However, at the end of day 1, there was lesser fluoride release with Cention, as compared with the other groups. Conclusion: The new Alkasite restorative material showed promising results in terms of fluoride release and is better than GIC and RMGIC at increased time duration.

Cepillado dental y niveles de flúor en pastas dentales usadas por niños peruanos menores de 12 años / Tooth brushing and fluoride levels in toothpaste used by peruvian children under 12 years old

RESUMEN Análisis secundario de los datos de 41 330 niños de uno a 11 años de la Encuesta Demográfica y de Salud Familiar (ENDES) 2018. Se reportó la frecuencia de cepillado y el uso de pasta dental según el nivel de flúor (no cepillado, adecuado, inadecuado, no mostró/no usa pasta, e ilegible), según variables socioeconómicas y geográficas. Un 7,8% de los niños evaluados no se cepillaba los dientes, se evidenció diferencias porcentuales significativas (p <0,001) en el uso de pasta dental con concentración inadecuada de flúor entre las categorías extremas de las variables edad (12,3%), uso de servicios odontológicos (7,7%), nivel educativo del responsable (20,4%), índice de riqueza (17,8%), dominio geográfico (11,3%) y área de residencia (9,1%). Un porcentaje considerable de niños peruanos no se cepilla los dientes; además, un gran número de niños que se cepillan emplean pastas dentales con contenidos de flúor sin efecto preventivo.

ABSTRACT Secondary analysis of data on 41,330 children aged one to 11 from the Demographic and Family Health Survey (ENDES) carried out in 2018. The frequency of brushing and the use of toothpaste were reported according to the level of fluoride (no brushing, adequate, inadequate, did not show/did not use toothpaste, and illegible), according to socioeconomic and geographical variables. The evaluation showed that 7.8% of children did not brush their teeth; there were significant percentage differences (p <0.001) in the use of toothpaste with inadequate fluoride concentration between the extreme categories of the variables: age (12.3%), use of dental services (7.7%), educational level of the person responsible (20.4%), wealth index (17.8%), geographical domain (11.3%), and area of residence (9.1%). A considerable percentage of Peruvian children do not brush their teeth; in addition, a large number of children who brush use toothpastes with a fluoride content that has no preventive effect.

Prevalência de fluorose dental em regiões abastecidas com água sem suplementação de flúor no território brasileiro: uma revisão sistemática e metanálise / Prevalence of dental fluorosis in regions supplied with non-fluoridated water in the Brazilian territory: a systematic review and meta-analysis

Resumo Trata-se de uma revisão sistemática e metanálise para estimar e comparar as prevalências de fluorose dental em localidades brasileiras abastecidas com água tratada sem suplementação de flúor e em localidades que utilizam de água de origem subterrânea. Em dezembro de 2016 foram buscados estudos transversais em 8 bases de dados incluindo a "literatura cinzenta". As prevalências foram estimadas utilizando modelo misto de efeitos aleatórios considerando as localidades como subgrupo. A heterogeneidade entre os estudos foi avaliada através da estatística I2 e do teste Q de Cochran. Foram encontrados 1.038 registros, dos quais apenas 18 artigos preencheram os critérios de inclusão, sendo submetidos para análise. O modelo metanalítico estimou em 8,92% (IC95%:5,41% até 14,36%) a prevalência de fluorose dental em municípios com água tratada sem suplementação de flúor e em 51,96% (IC95%: 31,03% até 72,22%) em municípios abastecidos por poços artesianos. A heterogeneidade entre os estudos foi alta, I2 = 95% (p < 0,01) no primeiro subgrupo de municípios e I2 = 98% (p < 0,01) no segundo subgrupo. A prevalência foi significativamente maior (p < 0,001) em populações expostas à água de poços artesianos, indicando que a presença de flúor natural em concentrações elevadas representa um fator de risco para a ocorrência de fluorose dental.

Abstract This systematic review and meta-analysis aimed to estimate and compare the prevalences of dental fluorosis in Brazilian cities supplied with non-fluoridated water and in locations that uses groundwater. In December of 2016, cross-sectional studies were searched in eight databases, including the "grey literature". The prevalences were estimated through a mixed random effects model considering the locations as subgroups. The heterogeneity among the studies was assessed with I2 statistics and the Cochran's Q test. A total of 1038 records were found, from which only 18 articles met the inclusion criteria and were subjected to analysis. The meta-analytic model estimated a prevalence of dental fluorosis of 8.92 % (95 % CI: 5.41 % to 14.36 %) in cities supplied with non-fluoridated water, and of 51.96 % (95 % CI: 31.03 % to 72.22 %) in cities supplied by artesian wells. The heterogeneity among the studies was high: I2 = 95 % (p < 0.01) in the first subgroup of cities and I2 = 98 % (p < 0.01) in the second subgroup. The prevalence was significantly higher (p < 0.001) in populations exposed to artesian well water, indicating that the presence of natural fluoride at high concentrations represents a risk factor for the occurrence of dental fluorosis.

Fluoride release and uptake in enhanced bioactivity glass ionomer cement ("glass carbomer™") compared with conventional and resin-modified glass ionomer cements

Abstract Objectives To study the fluoride uptake and release properties of glass carbomer dental cements and compare them with those of conventional and resin-modified glass ionomers. Materials and Methods Three materials were used, as follows: glass carbomer (Glass Fill), conventional glass ionomer (Chemfil Rock) and resin-modified glass ionomer (Fuji II LC). For all materials, specimens (sets of six) were matured at room temperature for time intervals of 10 minutes, 1 hour and 6 weeks, then exposed to either deionized water or sodium fluoride solution (1000 ppm in fluoride) for 24 hours. Following this, all specimens were placed in deionized water for additional 24 hours and fluoride release was measured. Results Storage in water led to increase in mass in all cases due to water uptake, with uptake varying with maturing time and material type. Storage in aqueous NaF led to variable results. Glass carbomer showed mass losses at all maturing times, whereas the conventional glass ionomer gained mass for some maturing times, and the resin-modified glass ionomer gained mass for all maturing times. All materials released fluoride into deionized water, with glass carbomer showing the highest release. For both types of glass ionomer, uptake of fluoride led to enhanced fluoride release into deionized water. In contrast, uptake by glass carbomer did not lead to increased fluoride release, although it was substantially higher than the uptake by both types of glass ionomer. Conclusions Glass carbomer resembles glass ionomer cements in its fluoride uptake behavior but differs when considering that its fluoride uptake does not lead to increased fluoride release.

The in vitro remineralizing effect of CPP-ACP and CPP-ACPF after 6 and 12 weeks on initial caries lesion

Abstract Objective: The aim of this in vitro study was to determine the effects of remineralization promoting agents containing casein phosphopeptide-stabilized amorphous calcium phosphate (CPP-ACP), or CPP-ACP in combination with fluoride (CPP-ACPF) on artificial white spot lesions (WSLs) after 6 and 12 weeks. Methodology: White spot lesions were created on 123 sectioned premolars (246 specimens) with a demineralization solution during a 96 hours pH-cycling regime. Two experimental groups were created: a CPP-ACP group (Tooth Mousse™), and a CPP-ACPF group (Mi Paste Plus™). Additionally, two control groups were created, one using only a conventional toothpaste (1450 ppm fluoride) and another one without any working agents. All teeth were also daily brushed with the conventional toothpaste except the second control group. Tooth Mousse™ and Mi Paste Plus™ were applied for 180 seconds every day. The volume of demineralization was measured with transverse microradiography. Six lesion characteristics regarding the lesion depth and mineral content of WSLs were also determined. Results: The application of CPP-ACP and CPP-ACPF had a significant regenerative effect on the WSLs. Compared to Control group 1 and 2 the volume of demineralization after 6 weeks decreased significantly for CPP-ACP (respectively p<0.001 and p<0.001) and CPP-ACPF (respectively p=0.001 and p=0.003). The same trend was observed after 12 weeks. For the CPP-ACPF group, WSL dimensions decreased significantly between 6 and 12 weeks follow-up (p=0.012). The lesion depth reduced significantly after application of CPP-ACP and CPP-ACPF but increased significantly in the Control groups. Mineral content increased for CPP-ACP and CPP-ACPF after an application period of 12 weeks, but this was only significant for CPP-ACP. Conclusions: Long-term use of CPP-ACP and CPP-ACPF in combination with a conventional tooth paste shows beneficial effects in the recovery of in vitro subsurface caries lesions.

Caries lesion remineralization with fluoride toothpastes and chlorhexidine - effects of application timing and toothpaste surfactant

Abstract Habitual toothbrushing with fluoridated toothpaste followed by rinsing with antibacterial mouthwashes is a method to maintain good oral hygiene and to diminish the occurrence and severity of dental caries and periodontal disease. However, our understanding of how antimicrobial agents in mouthwashes affect fluoride-mediated caries lesion remineralization is still poor. Objective: The objectives of this in vitro study were a) to determine the effects of the waiting period of chlorhexidine (CHX) rinsing after fluoride toothpaste use and b) to further determine the effect of the type of toothpaste surfactant [sodium dodecyl sulfate (SDS) or cocamidopropyl betaine (CAPB)] on caries lesion remineralization associated with CHX rinsing. Material and Methods: Caries lesions were formed in bovine enamel specimens and assigned to 10 treatment groups (n=18) based on Vickers surface microhardness (VHN). Lesions were then pH-cycled for 10 days with daily regimen comprised of twice daily toothpaste slurry treatments (1150 ppm fluoride, with SDS or CAPB), followed by CHX solution treatments [0, 15, 30 or 60 minutes following slurry treatment or no CHX treatment (negative control)]. VHN was measured again and the extent of lesion remineralization calculated (∆VHN). Results: ∆VHN with SDS-toothpaste was significantly lower than with CAPB-toothpaste, indicating more remineralization for the CAPB-toothpaste. ∆VHN with 0-minute waiting time was significantly lower than with 30-minute waiting time and with negative control. Conclusions: The absence of CHX as an adjunct to fluoride toothpastes led to greater remineralization of enamel lesions compared with the immediate use of CHX treatment for both SDS- and CAPB-toothpastes. CAPB-toothpastes indicated significantly greater remineralization than SDS-toothpastes, and can be suggested for patients at high risk of caries. A 30-minute waiting time for CHX treatment is recommended after brushing.

Effects of experimental bleaching agents on the mineral content of sound and demineralized enamels

Abstract High concentrations of hydrogen peroxide can cause adverse effects on composition and structure of teeth. However, the addition of calcium and fluoride in bleaching agents may reduce enamel demineralization. Objective: To evaluate chemical changes of sound and demineralized enamels submitted to high concentrations of hydrogen peroxide containing fluoride (F) or calcium (Ca). Material and Methods: Enamel blocks of bovine incisors with standard dimensions were obtained and half of them were submitted to pH-cycling to promote initial enamel caries lesions. Sound and demineralized enamel samples were divided into (n=10): (C) Control (no whitening treatment); (HP) 35% hydrogen peroxide; and two experimental groups: (HPF) 35% HP+0.2% F and (HPC) 35% HP+0.2% Ca. Experimental groups were submitted to two in-office bleaching sessions and agents were applied 3 times for 15 min to each session. The control group was kept in remineralizing solution at 37°C during the bleaching treatment. The surface mineral content of sound and demineralized enamels was determined through Fourier Transform Raman spectroscopy (FT-Raman), Energy dispersive Micro X-ray fluorescence spectroscopy (μ-EDXRF); and the subsurface, through cross-sectional microhardness (CSMH). In addition, polarized light microscopy (PLM) images of enamel subsurface were observed. Results: According to three-way (FT-Raman and μ-EDXRF analyses) or two-way analysis of variance (ANOVA) (CSMH) and Tukey test (α=5%), the calcium or fluoride added to high-concentrated bleaching agents increased phosphate and carbonate concentrations on sound and demineralized enamels (p<0.05). However, HPC and HPF were unable to completely reverse the subsurface mineral loss promoted by bleaching on sound and demineralized enamels. The calcium/ phosphate (Ca/P) ratio of sound enamel decreased after HP treatment (p<0.001). Conclusion: Even though experimental bleaching agents with Ca or F reduced mineral loss for both sound and demineralized enamel surfaces, these agents were unable to reverse the enamel subsurface demineralization.

Doxycycline-containing glass ionomer cement for arresting residual caries: an in vitro study and a pilot trial

Abstract In a previous study, we demonstrated that the incorporation of doxycycline hyclate (DOX) into resin-modified glass ionomer cement (RMGIC) inhibited important cariogenic microorganisms, without modifying its biological and mechanical characteristics. In this study, we keep focused on the effect of that experimental material as a potential therapy for arresting residual caries by analyzing other in vitro properties and conducting a pilot clinical trial assessing the in vivo effect of DOX-containing RMGIC on residual mutans streptococci after partial carious removal in primary molars. Specimens of the groups RMGIC (control); RMGIC + 1.5% DOX; RMGIC + 3% DOX; and RMGIC + 4.5% DOX were made to evaluate the effect of DOX incorporation on surface microhardness and fluoride release of RMGIC and against biofilm of Streptococcus mutans. Clinical intervention consisted of partial caries removal comparing RMGIC and RMGIC + 4.5% DOX as lining materials. After 3 months, clinical and microbiologic evaluations were performed. Data were submitted to ANOVA/Tukey or Wilcoxon/Mann-Whitney set as α=0.05. Fluoride release and surface microhardness was not influenced by the incorporation of DOX (p>0.05). There was a significant reduction of S. mutans biofilm over the material surface with the increase of DOX concentration. After clinical trial, the remaining dentin was hard and dry. Additionally, mutans streptococci were completely eliminated after 3 months of treatment with RMGIC + 4.5% DOX. The incorporation of DOX provided better antibiofilm effect, without jeopardizing fluoride release and surface microhardness of RMGIC. This combination also improved the in vivo shortterm microbiological effect of RMGIC after partial caries removal.

TiF4 varnish protects the retention of brackets to enamel after in vitro mild erosive challenge

Abstract The effect of fluoride agents on the retention of orthodontic brackets to enamel under erosive challenge is little investigated. Objective: The aim of this study was to evaluate the effect of titanium tetrafluoride (TiF4) and sodium fluoride (NaF) agents on the shear bond strength of brackets to enamel and on the enamel microhardness around brackets under erosive challenge. Methods: Brackets were bonded to bovine incisors. Five groups were formed according to fluoride application (n=10): TiF4 varnish, TiF4 solution, NaF varnish, NaF solution and control (without application). The specimens were submitted to erosive challenge (90 s cola drink/2h artificial saliva, 4x per day for 7 days). Solutions were applied before each erosive cycle and varnishes were applied once. Vickers Microhardness (VHN) was obtained before and after all cycles of erosion and the percentage of microhardness loss was calculated. Shear bond strength, adhesive remnant index and polarized light microscopy were conducted after erosion. The data were analyzed by ANOVA, Tukey, Kruskal-Wallis and Mann-Whitney U tests (α=0.05). Results: The %VHN had no statistically significant differences among the experimental groups. However, considering the comparisons of all groups with the control group, TiF4 varnish showed the highest protection from enamel demineralization (effect size of 2.94, while the effect size for the other groups was >2.4). The TiF4 varnish group had significantly higher shear bond strength compared to other groups. There was no difference among groups for adhesive remnant index. Polarized light microscopy showed higher demineralization depth for the control group. Conclusions: Application of NaF and TiF4 agents during mild erosive challenge minimized the enamel mineral loss around brackets, however only the experimental TiF4 varnish was able to prevent the reduction of shear bond strength of brackets to enamel.

Effect of erosive challenges on deciduous teeth undergoing restorative procedures with different adhesive protocols - an in vitro study

ABSTRACT Objective: To evaluate the effect of erosive challenges on the tooth- restoration interface of deciduous teeth treated with different adhesive protocols. Material and Methods: Deciduous molars were cut mesiodistally, then embedded, abraded and polished (n=80). Samples were randomly divided according to the adhesive system used into: G1 (Adper Single Bond2®, etch-and-rinse), G2 (Universal Single Bond®, self-etching), G3 (OptibondFL®, etch-and-rinse with Fluoride) and G4 (BondForce®, self-etching with Fluoride). After standardized cavity preparation (2 mm diameter x 2 mm depth), adhesive systems were applied and samples were restored (composite resin Z350®). Half of the samples were exposed to erosive/abrasive cycles (n = 10, each adhesive group), and the other half (control group; n = 10) remained immersed in artificial saliva. For microleakage analysis, samples were submersed in methylene blue and analyzed at 40x magnifications. Cross-sectional microhardness (CSMH) was carried out (50 g/5 s) at 25 μm, 50 μm, and 100 μm from the eroded surface and at 25 μm, 75 μm, and 125 μm from the enamel bond interface. Results: Regarding microleakage, 7.5% of the samples showed no dye infiltration, 30% showed dye infiltration only at the enamel interface, and 62.5% showed dye infiltration through the dentin-enamel junction, with no difference between groups (p≥0.05). No significant difference was observed in CSMH at different depths (two-way ANOVA, p≥0.05). Conclusions: We did not observe significant changes in microleakage or CSMH after erosive/abrasive challenges in deciduous teeth treated with different adhesive protocols (etch-and-rinse and self-etching adhesives, with and without fluoride).

In vitro and in vivo evaluations of glass-ionomer cement containing chlorhexidine for Atraumatic Restorative Treatment

Abstract Objectives: Addition of chlorhexidine has enhanced the antimicrobial effect of glass ionomer cement (GIC) indicated to Atraumatic Restorative Treatment (ART); however, the impact of this mixture on the properties of these materials and on the longevity of restorations must be investigated. The aim of this study was to evaluate the effects of incorporating chlorhexidine (CHX) in the in vitro biological and chemical-mechanical properties of GIC and in vivo clinical/ microbiological follow-up of the ART with GIC containing or not CHX. Material and Methods: For in vitro studies, groups were divided into GIC, GIC with 1.25% CHX, and GIC with 2.5% CHX. Antimicrobial activity of GIC was analyzed using agar diffusion and anti-biofilm assays. Cytotoxic effects, compressive tensile strength, microhardness and fluoride (F) release were also evaluated. A randomized controlled trial was conducted on 36 children that received ART either with GIC or GIC with CHX. Saliva and biofilm were collected for mutans streptococci (MS) counts and the survival rate of restorations was checked after 7 days, 3 months and one year after ART. ANOVA/Tukey or Kruskal-Wallis/ Mann-Whitney tests were performed for in vitro tests and in vivo microbiological analysis. The Kaplan-Meier method and Log rank tests were applied to estimate survival percentages of restorations (p<0.05). Results: Incorporation of 1.25% and 2.5% CHX improved the antimicrobial/anti-biofilm activity of GIC, without affecting F release and mechanical characteristics, but 2.5% CHX was cytotoxic. Survival rate of restorations using GIC with 1.25% CHX was similar to GIC. A significant reduction of MS levels was observed for KM+CHX group in children saliva and biofilm 7 days after treatment. Conclusions: The incorporation of 1.25% CHX increased the in vitro antimicrobial activity, without changing chemical-mechanical properties of GIC and odontoblast-like cell viability. This combination improved the in vivo short-term microbiological effect without affecting clinical performance of ART restorations.

Effect of fluoride on salivary immunoglobulins and sialic acid

Summary Objective: The aim of our study was to evaluate the effect of fluoride on salivary immunoglobulin and sialic acid levels in children with dental fluorosis and healthy teeth who live in places with high fluoride concentration in drinking water. Method: Fifty-one (51) healthy children between 6 and 12 years old with no caries were randomly selected from primary schools enrolled in the dental-care program operated by the Department of Pediatric Dentistry. The children were divided into two groups: group I comprised 26 children with dental fluorosis [Thylstrup-Fejerskov Dental Fluorosis Index (TFI) = 4] who lived in Isparta (2.7-2.8 ppm), and group II consisted of 25 children without dental fluorosis who were born in low-fluoride areas and had lived in Isparta for only the previous two years. Stimulated and unstimulated saliva were collected and analyzed for fluoride, salivary immunoglobulins and sialic acid levels. Results: Sialic acid level was correlated negatively with age. Levels of secretory immunoglobulin A (sIgA) and secretory immunoglobulin G (sIgG) were higher in children with dental fluorosis compared with those in group II, although these differences were not significant. Conclusion: Increased sIgA and sIgG levels may arrest the progression of caries in subjects with dental fluorosis. Given the risks of dental fluorosis, further studies of the effects of different fluoride levels in drinking water on salivary composition of children with mixed dentition are needed to confirm the results of our study and to provide data for comparison.

Investigation on the biological effect of fluorine present on the surface of titanium implants: analysis of the reaction fluoride-titanium oxide / Investigación del efecto del fluoruro sobre la superficie de implantes de titanio: análisis de la reacción fluoruro-óxido de titanio

The aim of this work was to investigate the state of fluoride at the surface of fluoridemodified titanium implants, and to provide information to support or discard the hypothesis that fluoride ion participates in the osseointegration of implants. Titanium is coated with a 2-10 nm thick layer of stable and adherent TiO2, which reacts with fluoride as a function of the anion concentration. Under present experimental conditions, the half-life of the reaction is about 2 minutes at 17 °C. The stoichiometry of the reaction Ti:F is 0.46 ± 0.03, which do not differs significantly from 0.5, the ratio inferred from the reaction between sodium fluoride and TiO2: 3 TiO2 + 6 NaF Na2 TiF6 + 2 Na2 TiO3 . The reaction proceeds as a function of the fraction of anionic fluoride concentration, which increases from a minimum at pH 1 to a maximum close to pH 6. The number of fluoride mmoles that react with TiO2 grows exponentially as a function of fluoride concentration, towards a maximum at 0.24 M fluoride. According to literature reports, potassium hexafluorotitanate is insoluble in water and it decomposes by heating at 780 °C, indicating a high formation constant. It is concluded that the hexafluorotitanate would not ionize to provide fluoride ion to the implant-bone environment and to promote growth and differentiation of osteoblasts. The effect of fluoride on the surface of titanium sheet was investigated under SEM, showing that the titanium sheet surface is roughened and electron dispersive spectroscopic microanalysis indicated that fluorine is included in the TiO2 layer. (AU)

El objetivo de este trabajo fue investigar el estado del flúor en la superficie de implantes de titanio tratados con fluoruro de sodio y obtener información para descartar o apoyar la hipótesis de su participación en el proceso de osteo-integración. El titanio está recubierto con una capa estable y adherente de TiO2, de 2-10 nm de espesor, que reacciona con el fluoruro en función de la concentración del anión. En las condiciones experimentales utilizadas el tiempo de vida media de la reacción es de 2 minutos at 17 ºC, pH 5,5. La reacción procede en función de la fracción de fluoruro iónico de la concentración total de fluoruro, que aumenta de un mínimo a pH 1 a un máximo a pH 6. El número de µmoles de fluoruro que reaccionan con TiO2 crece exponencialmente en función de la concentración del anión, hacia un máximo a 0,244 M. La relación estequiométrica de la reacción Ti:F es 0.46 ± 0.03 no difiere significativamente de 0.5; relación inferida de la reacción: 3 TiO2 + 6 NaF Na2 TiF6 + 2 Na2 TiO3. Como el hexafluorurotitanato de potasio es insoluble en agua y tiene una elevada constante de formación (se descompone por calentamiento a 780 ºC), se concluye que no se disociará para proveer fluoruro a las células óseas en contacto con el implante. La observación al microscopio electrónico de barrido y el análisis por espectroscopía de dispersión de rayos X de la superficie de un trozo de hoja de titanio tratado con solución de NaF a pH 3.5, indicaron aumento de la rugosidad y presencia de flúor en la capa de TiO2. (AU)

Osseointegration of titanium implants anodized with and without fluoride in the electrolyte: a study in rats / Osteo-integración de implantes de titanio anodizado con y sin agregado de fluoruro en el electrolito: estudio en la rata

Based on the hypothesis that fluoride acts as a bone anabolic agent, the aim of this study was to measure in rats the osseointegration of implants (grade II titanium wire, 1 mm diameter, 4 mm long) submitted to anodic oxidation in 2 M phosphoric acid solution (control implants) or b) in 2 M phosphoric acid solution plus 0.2 M NaF (F-modified implants). Chemical composition of the implants surface was assessed by energy-dispersive X-ray spectroscopy. The surface of F-modified implants contained a 2.57% fluorine in weight. Adult male Sprague Dawley rats (300-350 g body weight) received two implants (in the femur and in the tibia, close to the knee) in each hind limb. Control and F-modified implants were inserted in the left and right hind limbs, respectively. Three weeks after surgery, the animals were sacrificed. The undecalcified bones were embedded in methylmetacrylate. Sections were obtained to measure two histomorphometric magnitudes: bone-toimplant contact (BIC) and bone volume in a defined volume of tissue around the implant (BV/TV). BIC was significantly increased on F-modified implants with respect to their controls (57.2%±3.3%, vs. 47.9±3.4, p<0.05). BV/TV did not differ significantly between F-modified and control implants (24.5±2.2% vs. 22.9±1.4, p=0.30). Profiles of the average gray pixel levels of pseudo3D images showed a greater roughness of F-modified implants respect to their controls (p<0.05). The relative contributions of surface roughness and its fluorine content to the osseointegration process requires further research. (AU)

Con la hipótesis de que el ión fluoruro actúa como anabólico sobre las células óseas, el objetivo de este trabajo fue determinar el grado de osteo-integración (en la rata) de implantes (alambre de titanio II, 1 mm de diámetro, 4 mm de largo) anodizados en solución de ácido fosfórico 2 M + NaF 0,2 M (implantes-F) comparados con implantes controles, anodizados en solución de ácido fosfórico 2 M. La composición química de la superficie de los implantes fue evaluada mediante el espectro de dispersión de rayos X producidos durante la observación en el microscopio electrónico de barrido. La superficie de los implantes-F contiene 2.57% de flúor. Ratas macho Sprague-Dawley recibieron dos implantes (en el fémur y en tibia, próximos a la rodilla). Los implantes-F y controles se insertaron en las patas izquierda y derecha respectivamente. En los cortes de hueso sin decalcificación previa se midió el contacto hueso-implante (BIC) y volumen óseo en un volumen definido de tejido (BV/TV). BIC fue significativamente mayor con los Implantes-F respecto de los controles (57,2±3,3% vs. 47,9±3,4, p<0,05). BV/TV no exhibió diferencias significativas entre implantes-F y controles (24,5±2,2% vs. 22,9±1,4, p=0,30). Los perfiles de los niveles de grises de los imágenes pseudo3D de las superficies de los implantes pusieron en evidencia la mayor rugosidad de los implantes-F respecto de los controles (p<0,05). Las contribuciones relativas de la rugosidad y del flúor en el proceso de osteo-integración requieren investigación adicional. (AU)

E-learning Activities to Complement Education in Cariology for Undergraduate Students

Objective: To evaluate activities performed in an e-learning platform after 2-year of implementation in terms of contents and functionality. Material and Methods: Elearning courses were prepared and created by two lecturers. Contents were intended for last year undergraduate students attending the pediatric dentistry discipline, and included different topics considered as relevant to the area. Given tele-courses from 2010-2012 as well as statistics and contents, provided by the platform, were collected for analysis. Results: Five tele-courses were proposed and the total participation was 322 students (mean-per-course±SD=64.4±17.2). On average, 15 tutors/course accompanied the process. Caries lesion detection and fluoride therapy were discussed in all modules, but different activities were focused in various aspects. Other topics were also included: caries activity (60%), caries risk assessment, oral hygiene and clinical examination (40%). Two lecturers were responsible for preparing exercises and tutors helped in the creation, revision and correction. The main type of validation was open questions (83%). A High level of students' access was observed during the 2-year-period (mean-per-course±SD=21372±6775,2). More than 32000 external visits of the topics were also seen. On average, 14 tutor/student feedbacks were sent per student in each tele-course. Conclusion: The use of an e-learning system has been used especially to complementing teaching in caries detection and management using fluorides. Telecourses have been highly accessed by undergraduate students and also, external participants.