Effect of Different Preparations of Fluoride Gel on Salivary pH of Albino Rats

Abstract Objective: To evaluate the effect of different preparations of fluoride gels on the salivary pH of albino rats. Material and Methods: This experimental study consisted of 40 Albino rats randomly divided into four equal groups. Group A was the control group and received no intervention. Experimental group B received a topical application of 0.2% sodium fluoride gel. Experimental group C received topical application of stannous fluoride gel 0.4%. Experimental group D received topical application of APF gel (1.23% acidulated phosphate fluoride gel). The different preparations of the gels were applied once daily for 4 minutes on the occlusal surface of the right maxillary molars for 14 days. Salivary pH values were recorded immediately after the application of gels with the help of pH paper on day 1 and day 14. Results: There was a significant difference in the pH level of groups B, C and D after 14 days of fluoride application (p < 0.05). The non-parametric Kruskal Wallis test was applied for the comparison between the groups. Conclusion: This study concluded that all the fluoride gels after administration caused the acidic pH of saliva with the most acidic effect produced by APF gel (AU).

Corrosion behavior of zirconia in acidulated phosphate fluoride

ABSTRACT Objective The corrosion behavior of zirconia in acidulated phosphate fluoride (APF) representing acidic environments and fluoride treatments was studied. Material and Methods Zirconia rods were immersed in 1.23% and 0.123% APF solutions and maintained at 37°C for determined periods of time. Surfaces of all specimens were imaged using digital microscopy and scanning electron microscopy (SEM). Sample mass and dimensions were measured for mass loss determination. Samples were characterized by powder X-ray diffraction (XRD) to detect changes in crystallinity. A biosensor based on electrochemical impedance spectroscopy (EIS) was used to detect ion dissolution of material into the immersion media. Results Digital microscopy revealed diminishing luster of the materials and SEM showed increased superficial corrosion of zirconia submerged in 1.23% APF. Although no structural change was found, the absorption of salts (sodium phosphate) onto the surface of the materials bathed in 0.123% APF was significant. EIS indicated a greater change of impedance for the immersion solutions with increasing bathing time. Conclusion Immersion of zirconia in APF solutions showed deterioration limited to the surface, not extending to the bulk of the material. Inferences on zirconia performance in acidic oral environment can be elucidated from the study.

Una década de monitoreo de plomo en sangre en niños escolares del área metropolitana de Monterrey, NL / A decade of lead monitoring in schoolchildren in the metropolitan area of Monterrey NL, Mexico

Objetivo. Establecer las concentraciones de plomo (Pb) en sangre en niños escolares de 1998 y 2008, así como su asociación con factores de riesgo. Material y métodos. Se llevó a cabo un monitoreo de Pb en sangre de niños de entre 6 y 12 años que cursan educación primaria en 17 escuelas diferentes, ubicadas en distintas zonas del área metropolitana de Monterrey, de 1998 a 2008. Resultados. Se obtuvieron niveles séricos de 9.6 ± 3.0 (µg/dL rango de 3.18 a 20.88) en 1998 y de 4.5±4.8 µg/dL (rango de 3.3 a 53.7) en 2008, lo que mostró una disminución de 2.1 veces en nivel de Pb (p<0.01). Conclusiones. La reducción de los niveles séricos de Pb demuestran los mejores controles ambientales e industriales y probablemente el éxito de retirar el Pb de la gasolina durante los años noventa.

Objective. To establish the blood lead concentration and associated risk factors in schoolchildren during 1998 and 2008. Materials and methods. A blood lead screening was conducted in schoolchildren of 6-12 years of age, enrolled in 17 elementary schools of the metropolitan area of Monterrey, México, during 1998 and 2008. Results. The mean blood lead level were 9.6 ± 3.0 (µg/dL range of 3.18 to 20.88) in 1998 and 4.5±4.8 µg/dL (range of 3.3 to 53.7) showing a 2.1-times reduction in blood lead levels (p<0.01). Conclusions. This reduction in blood lead levels demonstrate environmental and industrial control improvements and the benefits of fading out the leaded gasoline during the 1990's.

Effect of fluoride solutions on the shear bond strength of orthodontic brackets

The aim of this in vitro study was to evaluate the shear bond strength of brackets after pre-treatment with different fluoride solutions. This study used 48 freshly extracted sound bovine incisors that were randomly assigned to 4 experimental groups (n=12). CG: (control) without treatment; NF: 4 min application of neutral fluoride; APF: application of 1.23% acidulated phosphate fluoride (APF) for 4 min; and SFV: application of 5% sodium fluoride varnish for 6 h. For each group, after surface treatment, prophylaxis of enamel and bracket bonding with Transbond XT composite resin (3M) were performed following the manufacturer's specifications. The shear bond strength was performed with a universal testing machine 24 h after fixing the brackets. The tooth surfaces were analyzed to verify the adhesive remnant index (ARI). Data were analyzed statistically by ANOVA and Tukey's test (α=0.05). There was statistically significant difference among the groups (p<0.0001). CG and NF groups presented significantly higher bond strength than APF and SFV. There was no significant difference between CG and NF or between APF and SFV (p>0.05). The analysis of ARI scores revealed that most failures occurred at the enamel-resin interface. It may be concluded that the pre-treatment of enamel with 1.23% APF and 5% SFV prior to fixing orthodontic brackets reduces shear bond strength values.

O objetivo deste estudo foi o de avaliar in vitro a resistência adesiva de bráquetes após o pré-tratamento do esmalte com diferentes soluções fluoretadas. Foram utilizados 48 incisivos bovinos hígidos recém-extraídos que foram aleatoriamente divididos em 4 grupos experimentais (n=12). CG (controle): sem tratamento; FN: aplicação de flúor neutro por 4 min; FFA: aplicação de flúor fosfato acidulado (FFA) a 1,23% por 4 min; e VFS: aplicação de verniz de fluoreto de sódio a 5% por 6 h. Após o tratamento dos grupos, foi realizada a profilaxia do esmalte e os bráquetes foram fixados utilizando o compósito Transbond XT (3M), seguindo as especificações do fabricante. A resistência adesiva foi verificada através do teste de cisalhamento, realizado na Máquina de Ensaio Universal DL-2000 24 h após a fixação dos bráquetes. As superfícies dos dentes foram analisadas para verificação do índice de adesivo remanescente (IAR). Por meio dos testes estatísticos ANOVA e Tukey (α=5%), observou-se diferença estatisticamente significante entre os grupos estudados (p<0,0001), sendo que GC e FN, apresentaram valores superiores de resistência adesiva quando comparados aos grupos FFA e VFS, porém GC-NF e FFA-VFS não apresentaram diferenças estatisticas entre si (p>0,05). A análise dos escores do IAR revelou que grande parte das falhas ocorreram na interface esmalte-resina. Conclui-se que o tratamento do esmalte com FFA 1,23% e VFS a 5%, previamente à fixação de bráquetes ortodônticos, reduziu os valores de resistência adesiva ao cisalhamento.

Comparison of the effect of topical fluorides on the commercially available conventional glass ionomers, resin modified glass ionomers and polyacid modified composite resins--an in vitro study.

This study was undertaken to assess the effect of a single application of three professionally applied topical fluoride agents (Sodium fluoride 2%, Stannous fluoride 8% and APF 1.23%) on the surfaces of six modern esthetic restorative materials used in pediatric dentistry viz., two conventional glass ionomers (Fuji II and Shofu-restorative), two resin modified glass ionomers (Vitremer, with and without glaze, and Photac-fil Quick) and two Polyacid modified composite resins (Luxat and Hytac Aplitip). Mean surface roughness and surface micro hardness (SMH) measurements were the parameters employed for comparison. Results showed that APF gel applications significantly increased the surface roughness measurements and decreased SMH of all tested materials, which was pronounced in conventional glass ionomers when compared with resin modified glass ionomers and polyacid modified composite resins. NaF and SnF2 produced a statistically significant increase in the surface roughness of conventional glass ionomers without any significant change in surface roughness and SMH on rest of the materials tested, except for NaF on SMH values of Fuji II, which was statistically significant.

Fluoride release by restorative materials before and after a topical application of fluoride gel

The release of fluoride from restorative materials (Vitremer, Ketac-Fil, Fuji II LC and Freedom) was evaluated during two 15-day periods, before and after a topical application of acidulated phosphate fluoride gel (APF). For each material, 6 specimens were made, which were immersed in 2 ml of deionized water. The fluoride concentration dosages in the solutions were read at intervals of 24 hours for 15 days. After this period, the specimens of each material received treatment with APF gel for 4 minutes and the fluoride released was analyzed at 24-hour intervals during the following 15 days. The analysis of variance and the Tukey test (p < 0.05) showed that the total mean fluoride released during the initial 15 days was greater for Vitremer and Ketac-Fil and lower for Fuji II LC and Freedom; and in the final 15 days there was a difference in release readings, with the greatest value for Vitremer, followed by Fuji II LC, Ketac-Fil and Freedom. The comparison of the results between the 1st day and the 16th day (after gel application) showed a greater fluoride release on the 16th day for Vitremer, Fuji II LC and Freedom and was equal for Ketac-Fil. Although all the materials evaluated gained fluoride with the application of APF, the data suggest that the resin-modified ionomers are more efficient in releasing fluoride to the medium than the other materials