Acidulated Phosphate Fluoride Gel Research Articles

Evaluation of crystalline changes and resistance to demineralization of the surface of human dental enamel treated with Er:YAG laser and fluoride using x-ray diffraction analysis and Vickers microhardness

This study aimed to investigate the changes in crystalline structure and resistance to demineralization of human dental surface enamel treated with erbium-doped yttrium aluminium garnet laser (Er:YAG) laser and fluoride.The enamel surfaces were divided into four groups according to the treatment process including, (L): irradiated with Er:YAG; (F): treated with acidulated phosphate fluoride gel (LF): Pre-irradiated surfaces with Er:YAG subjected to acidulated phosphate fluoride gel and (FL): laser irradiation was performed on the fluoridated enamel surface. Before and after the treatment procedure, the samples were evaluated using X-ray diffraction, scanning electron microscope (SEM) and the Vickers microhardness test. The surface microhardness values also were measured after a pH-cycling regime and acid challenge.The a-axis of all lased groups was contracted after treatment procedure. Measurement of the area under the peaks showed the highest crysallinity in the FL group. The hardness values of all laser treated samples significantly reduced after treatment procedure compared to the F group (p ⩽ 0.001). The morphological observations showed remarkable changes on the lased enamel surfaces including cracks, craters and exposed prisms.These findings suggest, irradiation of the Er:YAG laser accompanying with fluoride application can induce some beneficial crystalline changes regarding the acid-resistance properties of enamel, however, the craters and cracks produced by laser irradiation can promote enamel demineralization and consequently the positive effects of the Er:YAG laser will be eliminated.

Corrosion of metal orthodontic brackets and archwires caused by fluoride-containing products: Cytotoxicity, metal ion release and surface roughness

PurposeThe aims of this study were to determine the cytotoxicity, metal ion release and surface roughness of metal orthodontic appliances after immersion in different fluoride product solutions. Materials and methodsTwelve sets of 20 brackets and four tubes were ligated with three types of archwires: stainless steel, nickel-titanium, and beta-titanium. The samples in each archwire group were divided into three subgroups and immersed in solutions of fluoride toothpaste, 1.23% acidulated phosphate fluoride (APF), or artificial saliva without fluoride as a control group. The immersion times were estimated from the recommended time of using each fluoride product for 3 months. The samples were immersed in cell culture medium for 7 days. Primary gingival fibroblast cell viability was determined by an MTT assay. Metal ion (nickel, chromium, iron, and molybdenum) release and surface roughness were measured by inductively coupled plasma mass spectroscopy and a noncontact optical 3-dimensional surface characterization and roughness measuring device, respectively. The bracket and wire surface morphology was observed using scanning electron microscopy. The data were analysed by Two-way ANOVA. ResultsIn the APF groups, the four metal ion levels and surface roughness of the brackets and archwires significantly increased, while cell viability significantly decreased, especially in the TMA subgroup. The SEM results showed that the brackets and wires in the APF groups demonstrated more lines and grooves compared with the other groups. ConclusionUsing APF gel during orthodontic treatment with fixed metal appliances should be avoided.

Dental caries prevention strategies among children and adolescents with immigrant\xa0- or low socioeconomic backgrounds- do they work? A systematic review

BackgroundThis systematic review was designed to uncover the most reliable evidence about the effects of caries preventive strategies in children and adolescents of immigrant or low socioeconomic backgrounds.MethodsAccording to pre-determined inclusion and exclusion criteria, relevant articles focusing on underprivileged groups were electronically selected between January1995 and October 2015. The literature search was conducted in five databases; PubMed, Embase, CINAHL, SweMed+ and Cochrane Library. Accepted languages for included articles were English, German and Scandinavian languages. s and selected articles in full text were read and assessed independently by two review authors. Systematic reviews and meta-analyses were not included. Also articles with topics of water fluoridation and fluoride toothpaste were excluded, this due to all existing evidence of anti-caries effect for disadvantaged groups. The key data about the main characteristics of the study were compiled in tables and a quality grading was performed.ResultsThirty-seven articles were selected for further evaluation. Supervised toothbrushing for 5-year-old school children was found to be an effective prevention technique for use in underprivileged groups. Also a child/mother approach, targeting nutrition and broad oral health education of mothers showed effectiveness. For older children, a slow-release fluoride device and application of acidulated phosphate fluoride (APF) gel showed to be effective.ConclusionOn the basis of this review, we maintain that in addition to studies of water fluoridation and fluoride toothpaste, there are other preventive intervention studies providing scientific evidence for caries reduction among children and adolescents with immigrant or low socioeconomic backgrounds.

Effect of Acidulated Phosphate Fluoride Gel on the Surface of Dental Nanocomposite Restorative Materials

The aim of this in vitro study was to investigate the changes in surface roughness of different nanocomposite restoratives and enamel after application of 1.23% acidulated phosphate fluoride (APF) gel. Twelve specimens were prepared for each composite material and human enamel. The APF gel was applied to the surface of the six specimens of each experimental group for 60 sec every 24 h for 4 days. The other six specimens did not receive APF treatment (control). The surface roughness was measured using a VSI microscope. One-way ANOVA and Tukey’s test were used to compare surface roughness between materials for each experimental group at a level of significance of a=0.05. There were no statistically significant differences in Ra values among the composites which did not receive APF treatment (p>0.05). After APF treatment the lowest surface roughness exhibited enamel (0.18±0.04 Ra) and the highest Dyract Extra (0.62±0.07 Ra) followed by Tetric EvoCeram (0.59±0.06 Ra) and Beautifil II (0.51±0.06 Ra). Filtek Z350 XT presented the lowest Ra values (0.23±0.03). All the experimental groups exhibited higher Ra values after APF treatment (p<0.05), except for Filtek Z350 XT (p>0.05). Application of APF gel on the specimen surfaces influenced the surface roughness of enamel and the tested dental composite restoratives depending on their composition.

Effect of the carbon dioxide 10,600-nm laser and topical fluoride gel application on enamel microstructure and microhardness after acid challenge: an in vitro study.

The aim of this in-vitro study was to evaluate positive effects of the carbon dioxide laser (CO2, 10,600nm) with acidulated phosphate fluoride (APF) gel on enamel acid resistance. Twenty extracted human third molars (40 surfaces) were randomly assigned into four groups: group C, untreated control; group L, CO2 laser alone group; group F, APF 1.23% fluoride gel; and group FL, APF 1.23% gel and laser. Samples from group L were irradiated with a CO2 laser for 30s. The parameter settings used were average power, 0.73W; time on, 100μs; time off, 40ms; tip-to-tissue distance, 20mm; tip diameter 700μm; and energy density with movements, 5J/cm2. Samples from group F were treated with the APF gel for 4min, and the gel was washed off with distilled water. The enamel samples from group FL were treated with APF gel for 4min and then irradiated with the CO2 laser for 30s without removing the gel. Each enamel sample was placed in 50ml soft drink (pH = 2.75) for 10min then rinsed with deionized water and stored in artificial saliva at 37°C for 1h. Samples were assessed for Vickers hardness number (VHN) before and after treatments and subjected to SEM analysis. Data were analyzed using a one-way analysis of variance (ANOVA) and Tukey's test (α < 0.05). After the acid challenge, the untreated C group was demineralized to a great extent and the enamel surface was with the lowest mean score of microhardness. The observed VHN in the control (C group) had a mean value of 176.13, the scores in the CO2 laser group (L group) were with mean value of 238.40, the F group with a mean value of 218.45, and the fluoride-treated and laser-irradiated FL group-with a mean of 268.28 VHN. Paired t test performed to compare groups C, L, F, and FL has shown that group FL has greater resistance to decrease in microhardness of dental enamel (P ≤ 0.05) on exposure to acidic protocol. After the acid challenge, the fluoride-treated and laser-irradiated samples (group FL) showed the least diminution in enamel surface microhardness. The sub-ablative carbon dioxide laser irradiation in combination with fluoride treatment is more effective in protecting enamel surface and resisting demineralization than CO2 laser irradiation or fluoride alone.

Comparative evaluation of fluoride release and recharge potential of novel and traditional fluoride-releasing restorative materials: An in vitro study.

Aim:The aim of this study was to evaluate and compare the fluoride ion release and uptake of glass ionomer cement GP IX Extra (GE), EQUIA® Forte Fil (EF), Beautifil Bulk (BB), Dyract® XP (DXP), Tetric N-Ceram® (TNC) in vitro.Materials and Methods:The restorative materials were divided into five groups (n = 12), namely G1 – GE, G2 – EF, G3 – BB, G4 – DXP, G5 – TNC. Fluoride release was checked using fluoride ion-selective electrode (Orion 9609BNWP, Ionplus Sure-Flow Fluoride, Thermo Scientific, USA) at time intervals of 1 day and thereafter at 3, 7, 14, 21, and 28 days. Following this, fluoride recharge was done with 1.23% acidulated phosphate fluoride gel (12,300 ppm, Pascal International Inc., 2929 Northup Way, Bellevue, USA) after 28 days and each sample was re-checked for fluoride release at the same time intervals.Statistical Analysis:One-way ANOVA with post hoc Games–Howell test for intergroup and repeated measures ANOVA with post hoc Bonferroni test for intragroup analysis. P < 0.05 was considered statistically significant.Results:On intergroup analysis, Group 2 showed high values of fluoride release and recharge at all-time intervals which were significantly higher (P < 0.001) than Groups 1, 3, 4 and 5. Intragroup analysis showed significantly higher (P < 0.001) fluoride release and recharge at the end of day 1 which decreased progressively with time for all the tested materials.Conclusion:EF showed the highest fluoride release and recharge potential across all time intervals compared to other tested restorative materials and the greatest fluoride release was seen on day 1.

Evaluation of Interactions of Surface Fluorides on Nickel–chromium and Casted Titanium Alloys: An In Vitro Study

The present study was conducted to assess the effects of topical fluoride on casted Titanium and nickel chromium using Scanning Electron Microscope. This in vitro study comprised of 45 specimens of Titanium and 45 specimens of nickel-chromium of same dimensions. They were divided into three groups of 15 each. GroupI specimens were immersed in 2% neutral sodium fluoride (NaF) solution for 16 minutes. Group II specimens were placed in 1.23% acidulated phosphate fluoride (APF) gel for eight minutes. Group III specimens were placed in distilled water for 8 minutes. All specimens were evaluated for surface roughness using a scanning electron microscope. Data thus obtained were subjected to statistical analysis including post-hoc test and analysis variance (ANOVA). There was no significant increase in surface roughness of nickel- chromium specimens in group I, II and III (p > 0.05) whereas Titanium specimens in group II showed a substantial increase in surface roughness (p < 0.05). There was surface corrosion of Titanium specimens and slight pitting of nickel-chromium specimens in group II. The studied preparation (1.23%) of acidulated phosphate fluoride has shown to affect the surface roughness of Titanium and nickel-chromium specimens whereas 2% neutral sodium fluoride and distilled water has no noticeable effect, therefore, providing some logical clinical correlations. Clinicians must be well known about the logical usages of topical fluorides in dentistry. Different fluoride concentrations and preparations are capable of producing prosthesis's surface roughness of various degrees. Surface roughness is acting as potent areas of bacterial adhesion, plaque retention, calculus retention and microcrack formation with poor esthetics and therefore it significantly affect long-term prosthesis success. Thus, the operator must be very critically monitoring and managing the harmful effects of acidic fluoridated on prosthesis made up of casted Titanium and nickel-chromium.

Retention Improvement in Fluoride Application with Cold Atmospheric Plasma

This study aimed to apply fluoride formulations to enamel with cold atmospheric plasma (CAP) and analyze the fluoride uptake, retention, and acid resistance quantitatively. Human enamel specimens were divided randomly into 2 groups: group APF1, 1.23% acidulated phosphate fluoride (APF) gel; group APF2, 1.23% APF gel with CAP. Fluoride and CAP were applied to the samples 4 times at 1-wk intervals. The specimens were also stored in artificial saliva for 4 wk to evaluate the retention of fluoride. The fluoride content on the fluoride-treated enamel was measured by an electron probe microanalyzer. To detect the resistance to demineralization, the calcium-to-phosphate ratio of the enamel samples was measured after the application of APF gel with or without CAP, followed by soaking in the demineralization solution. In groups APF1 and APF2, the amount of fluoride detected increased depending on the application frequency, and more fluoride was detected in group APF2 than in group APF1. In the experiment examining the maintenance effect, fluoride was not detected in group APF1, whereas fluoride was detected in group APF2 up to the fourth week. As for the resistance to demineralization, the calcium-to-phosphate ratio of the enamel treated with APF and CAP was higher than that treated with APF alone, and it increased with the frequency of treatment. This study suggests that the combination treatment of CAP and fluoride improves retention of fluoride on the enamel and resistance to demineralization when compared with treatment with fluoride alone.

Influence of multi-wavelength laser irradiation of enamel and dentin surfaces at 0.355, 2.94, and 9.4 μm on surface morphology, permeability, and acid resistance.

Ultraviolet (UV) and infrared (IR) lasers can be used to specifically target protein, water, and mineral, respectively, in dental hard tissues to produce varying changes in surface morphology, permeability, reflectivity, and acid resistance. The purpose of this study was to explore the influence of laser irradiation and topical fluoride application on the surface morphology, permeability, reflectivity, and acid resistance of enamel and dentin to shed light on the mechanism of interaction and develop more effective treatments. Twelve bovine enamel surfaces and twelve bovine dentin surfaces were irradiated with various combinations of lasers operating at 0.355 (Freq.-tripled Nd:YAG (UV) laser), 2.94 (Er:YAG laser), and 9.4 μm (CO2 laser), and surfaces were exposed to an acidulated phosphate fluoride gel and an acid challenge. Changes in the surface morphology, acid resistance, and permeability were measured using digital microscopy, polarized light microscopy, near-IR reflectance, fluorescence, polarization sensitive-optical coherence tomography (PS-OCT), and surface dehydration rate measurements. Different laser treatments dramatically influenced the surface morphology and permeability of both enamel and dentin. CO2 laser irradiation melted tooth surfaces. Er:YAG and UV lasers, while not melting tooth surfaces, showed markedly different surface roughness. Er:YAG irradiation led to significantly rougher enamel and dentin surfaces and led to higher permeability. There were significant differences in acid resistance among the various treatment groups. Surface dehydration measurements showed significant changes in permeability after laser treatments, application of fluoride and after exposure to demineralization. CO2 laser irradiation was most effective in inhibiting demineralization on enamel while topical fluoride was most effective for dentin surfaces. Lasers Surg. Med. 49:913-927, 2017. © 2017 Wiley Periodicals, Inc.

Multi-walled carbon nanotubes/graphene oxide hybrid and nanohydroxyapatite composite: A novel coating to prevent dentin erosion

To date is emergent the development of novel coatings to protect erosion, especially to preventive dentistry and restorative dentistry. Here, for the first time we report the effectiveness of multi-walled carbon nanotube/graphene oxide hybrid carbon-base material (MWCNTO-GO) combined with nanohydroxyapatite (nHAp) as a protective coating for dentin erosion. Fourier transform Raman spectroscopy (FT-Raman), scanning electron (SEM), and transmission electron (TEM) microscopy were used to investigated the coatings and the effect of acidulated phosphate fluoride gel (APF) treatment on bovine teeth root dentin before and after erosion. The electrochemical corrosion performance of the coating was evaluated. Raman spectra identified that: (i) the phosphate (ν1PO43−) content of dentin was not significantly affected by the treatments and (ii) the carbonate (ν1CO32−) content in dentin increased when nHAp was used. However, the nHAp/MWCNTO-GO composite exposited lower levels of organic matrix (CH bonds) after erosion compared to other treatments. Interesting, SEM micrographs identified that the nHAp/MWCNTO-GO formed layers after erosive cycling when associate with APF treatment, indicating a possible chemical bond among them. Treatments of root dentin with nHAp, MWCNTO-GO, APF_MWCNTO-GO, and APF_nHAp/MWCNTO-GO increased the carbonate content, carbonate/phosphate ratio, and organic matrix band area after erosion. The potentiodynamic polarization curves and Nyquist plot showed that nHAp, MWCNT-GO and nHAp/MWCNT-GO composites acted as protective agents against corrosion process. Clearly, the nHAp/MWCNTO-GO composite was stable after erosive cycling and a thin and acid-resistant film was formed when associated to APF treatment.

Introducing mini clinical evaluation exercise for assessing preventive procedure - 1.23% acidulated phosphate fluoride gel application by final year dental students

Introducing mini clinical evaluation exercise for assessing preventive procedure - 1.23% acidulated phosphate fluoride gel application by final year dental students

Effect of 5,000 ppm Fluoride Dentifrice or 1,100 ppm Fluoride Dentifrice Combined with Acidulated Phosphate Fluoride on Caries Lesion Inhibition and Repair

High fluoride dentifrice (FD; 5,000 ppm F) has been recommended to arrest root dentine lesions and to control enamel caries in high-risk patients. Also, standard FD (1,100 ppm F) in combination with professional fluoride application has been recommended to control dentine caries, but the effect of this combination on enamel has been considered modest. Considering the lack of evaluation comparing the use of 5,000 ppm FD (5,000-FD) versus acidulated phosphate fluoride (APF) application combined with 1,100 ppm FD (1,100-FD) on the inhibition and repair of caries lesions in both enamel and dentine, we conducted this in situ, double-blind, crossover study of 3 phases of 14 days. In each phase, 18 volunteers wore palatal appliances containing enamel and root dentine specimens, either sound or carious, to evaluate the effect of the treatments on the inhibition or repair of caries lesions, respectively. The treatments were non-FD (negative control), 5,000-FD, or 1 APF gel application on dental specimens combined with 1,100-FD used twice per day (APF + 1,100-FD). The reduction of demineralization and enhancement of remineralization were assessed by surface and cross-sectional hardness. Fluoride concentration was determined on dental specimens and on the formed biofilm. For enamel, APF + 1,100-FD and 5,000-FD did not differ regarding the inhibition of demineralization and repair of caries lesions. However, for dentine the difference between these treatments was inconclusive because while APF + 1,100-FD was more effective than 5,000-FD in caries lesion reduction and repair, 5,000-FD was more effective than APF + 1,100-FD in the reduction of surface demineralization. Therefore, the findings show that the combination of APF + 1,100-FD is as effective as 5,000-FD in enamel inhibition of demineralization and enhancement of remineralization.

Effect of Different Topical Fluoride on the Surface Roughness of Glass Ionomer Cement

&lt;div class="WordSection1"&gt;&lt;p class="AbstractContent"&gt;&lt;strong&gt;Objective&lt;/strong&gt;: To evaluate the effect of acidulated phosphate fluoride (APF) gel and sodium fluoride (NaF) gel on the surface roughness of glass ionomer cements.&lt;/p&gt;&lt;p class="AbstractContent"&gt;&lt;strong&gt;Methods:&lt;/strong&gt; Twenty disc-shaped samples were fabricated from glass ionomer cement (Fuji II, GC Gold Label, Japan) and divided into two test groups that is group I for acidulated phosphate fluoride (APF) gel application and group II for sodium fluoride (NaF) gel application. After 24 hours, the surface roughness (Ra) was determined using a profilometer (MarSurf M300, Germany). Samples surface were applied by topical fluoride gel according test group for 4 minutes. After the treatment, the surface roughness (Ra) was determined using a profilometer. T test was used to evaluate surface roughness measurement and the differences in surface roughness values between test groups.&lt;/p&gt;&lt;p class="AbstractContent"&gt;&lt;strong&gt;Results&lt;/strong&gt;: Acidulated phosphate fluoride gel group showed the highest surface roughness than sodium fluoride group. There were significant differences between test groups (&lt;em&gt;p&lt;/em&gt; = 0.00).&lt;/p&gt;&lt;p class="AbstractContent"&gt;&lt;strong&gt;Conclusion&lt;/strong&gt;: Acidulated phosphate fluoride gel can cause surface roughness on the glass ionomer cement more than sodium fluoride gel.&lt;/p&gt;&lt;div&gt;&lt;p class="Keywords" align="left"&gt;&lt;em&gt;Keywords: acidulated phosphate fluoride, glass ionomer cements, sodium fluoride&lt;/em&gt;&lt;em&gt;, surface roughness&lt;/em&gt;&lt;em&gt;&lt;/em&gt;&lt;/p&gt;&lt;/div&gt;&lt;/div&gt;&lt;em&gt;&lt;br clear="all" /&gt;&lt;/em&gt;

CO2 laser and/or fluoride enamel treatment against in situ/ex vivo erosive challenge

ABSTRACTObjective This in situ/ex vivo study investigated the effect of CO2 laser irradiation and acidulated phosphate fluoride gel (APF) application, separately and in combination, on enamel resistance to erosion.Material and Methods During 2 experimental 5-day crossover phases, 8 volunteers wore intraoral appliances containing bovine enamel blocks which were submitted to four groups: 1st phase - control, untreated and CO2 laser irradiation, 2nd phase - fluoride application and fluoride application before CO2 laser irradiation. Laser irradiation was performed at 10.6 µm wavelength, 5 µs pulse duration and 50 Hz frequency, with average power input and output of 2.3 W and 2.0 W, respectively (28.6 J/cm2). APF gel (1.23%F, pH 3.5) was applied on enamel surface with a microbrush and left on for 4 minutes. Then, the enamel blocks were fixed at the intraoral appliance level. The erosion was performed extraorally 4 times daily for 5 min in 150 mL of cola drink. Enamel loss was measured profilometrically after treatment and after the in situ phase. The data were tested using one-way Repeated Measures Anova and Tukey's test (p<0.05).Results CO2 laser alone (2.00±0.39 µm) did not show any significantly preventive effect against enamel erosion when compared with the control group (2.41±1.20 µm). Fluoride treated enamel, associated (1.50±0.30 µm) or not (1.47±0.63 µm) with laser irradiation, significantly differed from the control.Conclusion The APF application decreased enamel wear; however, CO2 laser irradiation did not enhance fluoride ability to reduce enamel wear.

CO2 laser irradiation enhances CaF2 formation and inhibits lesion progression on demineralized dental enamel-in vitro study.

This study evaluated if Carbon dioxide (CO2) (λ 10.6 μm) laser irradiation combined with acidulated phosphate fluoride gel application (APF gel) enhances "CaF2" uptake by demineralized enamel specimens (DES) and inhibits enamel lesion progression. Thus, two studies were conducted and DES were subjected to APF gel combined or not with CO2 laser irradiation (11.3 or 20.0 J/cm(2), 0.4 or 0.7 W) performed before, during, or after APF gel application. In study 1, 165 DES were allocated to 11 groups. Fluoride as "CaF2 like material" formed on enamel was determined in 100 DES (n = 10/group), and the surface morphologies of 50 specimens were evaluated by scanning electron microscopy (SEM) before and after "CaF2" extraction. In study 2, 165 DES (11 groups, n = 15), subjected to the same treatments as in study 1, were further subjected to a pH-cycling model to simulate a high cariogenic challenge. The progression of demineralization in DES was evaluated by cross-sectional microhardness and polarized light microscopy analyses. Laser at 11.3 J/cm(2) applied during APF gel application increased "CaF2" uptake on enamel surface. Laser irradiation and APF gel alone arrested the lesion progression compared with the control (p < 0.05). Areas of melting, fusion, and cracks were observed. CO2 laser irradiation, combined with a single APF application enhanced "CaF2" uptake on enamel surface and a synergistic effect was found. However, regarding the inhibition of caries lesion progression, no synergistic effect could be demonstrated. In conclusion, the results have shown that irradiation with specific laser parameters significantly enhanced CaF2 uptake by demineralized enamel and inhibited lesion progression.

Influência da aplicação tópica de géis de flúor na rugosidade superficial de cimentos de ionômero

Avaliar a morfologia de superfície de quatro CIVs (cimentos de ionômero de vidro) quando submetidos à ação tópica do flúor fosfato acidulado a 1,23% e&#x0D; gel de fluoreto de sódio neutro a 2%. Foram confeccionados 10 espécimes de cada CIVs (Ketac Molar Easymix, Maxxion R, Vitro Molar e Vitremer). Um ensaio de rugosidade foi efetuado antes e após aplicação tópica de gel de flúor. Os dados obtidos foram analisados através do teste de Tukey e do teste T. Os&#x0D; valores de rugosidade apresentados pelos materiais, segui a ordem descrescente: Maxxion&gt;Ketac Molar Easy Mix&gt; Vitro Molar. A aplicação tópica de flúor acidulado apresentou alterações de superfície nos materiais avaliados.&#x0D; &#x0D; DOI: 10.18363/rbo.v72i1/2.594

Effect of fluoride agents on the color stability of esthetic restorative materials

Objective The aim of the study was to estimate the effect of acidulated phosphate fluoride (APF) gel and fluoride varnish on the color stability of esthetic restorative materials. Methodology The materials included were glass ionomer cement, resin-modified glass ionomer cement, and composite resin. A Teflon matrix (12×2 mm) mold was used to fabricate 108 specimens from all restorative materials. Further, 36 disks of each restorative material were then randomly divided into three groups (n = 12) according to the fluoride application: deionized water (control), APF (1.23%), and fluoride varnish. Color change was measured by means of a spectrophotometer using a CIE L*a*b* (Comission International l´Eclairage) system before and 24 h after fluoride treatment. Statistical comparisons were made using first mixed model repeated measure analysis of variance on the transform ranked data under the assumption of non-normal data and to see which main or interaction effect was significant. Results In control groups, when the baseline and final readings of glagg ionomer cement, resinmodified glass ionomer cement, and composite materials were compared for color changes, similar values were observed and hence results were nonsignificant. When all materials were compared for color changes before and after the application of APF, highly significant mean differences were found among the groups. Hence, application of APF results in a highly significant color change in all materials compared with varnish application. Conclusion Topical fluoride agents – either fluoride varnish or APF gels – cause discoloration in all esthetic restorative materials. However, this discoloration is not visually perceptible.

Inhibition of enamel demineralisation using "Nd-YAG and diode laser assisted fluoride therapy".

This in vitro study was to evaluate the irradiation efficacy of the Diode laser and the Nd-YAG laser either un-assisted or assisted by acidulated phosphate fluoride (APF) treatment on enamel's acid resistance. Seventy-two enamel samples, obtained from 12 extracted human molars, were randomly assigned to 6 groups as follows: (1) Control (C); (2) Exposed to APF gel (F); (3) Diode laser (DL); (4) Irradiated with Diode laser through APF gel (DL/F); (5) Nd-YAG laser (NL) and (6) Irradiated with Nd-YAG laser through APF gel (NL/F). The specimens were individually demineralised in an acidified hydroxyethylcellulose system, and the acid resistance was evaluated by determining the calcium ion dissolution using atomic absorption spectrometry. The average concentration of the calcium ion determined in groups 1 to 6 was 901, 757, 736, 592, 497 and 416 parts per million micrograms/gram, respectively. The results showed that demineralisation in the NL/F group was significantly less than the other groups and the control group was significantly greater than the other groups (P<0.001). The effect of Nd-YAG laser irradiation, used alone or in combination with APF, in decreasing the enamel demineralisation was greater than all the other groups.

Effect of acidulated phosphate fluoride application on microhardness of glass ionomer cement

Introduction: Acidulated phosphate fluoride (APF) gels are commonly used as preventive caries materials in paediatric dentistry while glass ionomer cements (GICs) are widely used as a restorative material. The purpose of this study was to determine the effect of acidulated phosphate fluoride application towards the microhardness of GIC. Methods: This study was an experimental laboratory study where ten specimens were prepared from high viscosity GIC, which was Fuji IX. Specimens were stored in 50 ml distilled water at first 24 hours at 37°C, and then specimens were divided into fluoride group which was immersed in 25 ml of 1.23 % APF gel and control group which was stored 25 ml distilled water for 24 hours at 37°C. The Micromet II Microhardness Tester, Buehler, IL, USA that was standardised for Vickers hardness test was used to test the specimens at 100-gram load. Data were analysed using the t-test comparison test. Results: The level of microhardness of the fluoride group (14.34) was much lower compared to the control group (43.21) with a highly significant difference (p&lt;0.01). Conclusion: The application of 1.23% APF gel on high viscosity GIC reduces the microhardness level compared to the control group.

Comparison of a 2-Year Oral Health Program Using Sealant and 1.23% Acidulated Phosphate Fluoride Gel in Primary School Students of Vientiane, Laos

Comparison of a 2-Year Oral Health Program Using Sealant and 1.23% Acidulated Phosphate Fluoride Gel in Primary School Students of Vientiane, Laos