Acidulated Fluoride Research Articles

Análise da rugosidade superficial de uma resina composta tratada com gel fluoretado em diferentes pH

Objetivo: O flúor acidulado é utilizado no controle da doença cárie, mas seus efeitos na superfície de resinas compostas são controversos. O objetivo do estudo é avaliar a rugosidade superficial de uma resina composta após a aplicação tópica de flúor in vitro. Métodos: Espécimes de resina Vittra (FGM) foram preparados (8mmx1mm) e polidos. Após avaliação do pH de produtos fluoretados, o de maior e menor pH foram selecionados para os experimentos. Foram testados três grupos experimentais (n=15): grupo 1 – flúor gel acidulado a 1,23% (Nova DFL) (menor pH:4,48±0,32), grupo 2 – flúor gel neutro a 2% (Nova DFL) (maior pH:7,03±0,40), grupo 3 – sem exposição ao flúor (controle negativo). O experimento simulou o protocolo padrão clínico de aplicação de flúor (uma aplicação por semana, durante um minuto, por quatro semanas). A rugosidade superficial foi mensurada antes e após o tratamento através de microscopia confocal e a característica superficial avaliada por imagens reconstruídas. Foi realizado teste ANOVA (post-hoc de Bonferroni) para comparar médias da rugosidade superficial entre grupos. Resultados: O grupo exposto ao flúor gel acidulado apresentou os maiores valores de rugosidade (Ra: 0,29±0,08), sendo maior que o grupo exposto ao gel neutro (Ra: 0,21±0,08) e controle (Ra: 0,23±0,05) (p

In vivo assessment of the corrosion of nickel-titanium orthodontic archwires by using scanning electron microscopy and atomic force microscopy.

This study was undertaken to assess in vivo the corrosion in two commercial nickel-titanium (NiTi) orthodontic archwires removed from the oral cavity of patients using fluoride mouthwashes. Five volunteers took part in this study on the corrosion behavior of two brands of NiTi archwires (3M and AO (brand of archwire)) during use of two mouthwashes with neutral sodium fluoride 1.1%, one with acidulated fluoride 1.1%, and one with placebo and a control group. Each patient used one mouthwash in three different periods of time for 1 min a day for 30 days. The archwires were assessed with scanning electron microscopy and atomic force microscopy for qualitative and quantitative analysis. The values obtained with atomic force microscopy (AFM) were submitted to normality test, two-way analysis of variance, and Tukey's test at a significance level of 5%. The AFM images showed a gradual qualitative increase in the roughness of both types of wire between the treatments: control < placebo < neutral fluoride < acidulated fluoride. The arithmetic average of the roughness and root mean square of the roughness were similar. As for 3M archwires, only the acidulated fluoride group differed statistically from the others. As for AO archwires, the control and placebo groups did not differ from each other, but differed from the other fluoride treatments. The group using neutral fluoride also differed significantly from the acidulated fluoride group. 3M archwires were not affected by daily oral challenges. AO archwires were not affected by daily oral challenges either; their association with fluoride, either neutral or acidulated, increased their roughness.

Efficacy of CO lasers in preventing dental caries in partially erupted first permanent molars: a randomized 18-month clinical trial.

The aim of this controlled randomized double-blinded clinical trial was to evaluate the use of a CO2 laser with or without topical application of acidulated fluorides in the prevention of dental caries in partially erupted first permanent molars. We selected 61 healthy children at high risk of caries, all between 6 and 8 (7.1 ± 0.8) years of age and with 4 partially erupted first permanent molars. A CO2 laser device emitting at 10.6μm was used (0.5W, 0.05mJ per pulse, 10kHz). Each first molar in an individual was randomly assigned to one treatment: (L) CO2 laser (0.066J/cm2); (FL) 1.23% acidulated fluoride gel and CO2 laser (0.066J/cm2); (V) 5% fluoride varnish, or (S) sealant (control). Patients were followed-up at 3, 6, 12, and 18months after treatment, through direct visual examination and by an operator blinded to the treatments (kappa ≥ 0.70). The International Caries Detection and Assessment System (ICDAS-II) index was used to assess the soundness of tooth structure or the presence of white spot lesions, cavitated enamel, and/or dentin lesions. The Yildiz Visual Index was used to evaluate sealant retention. Results were evaluated using Kaplan-Meier survival analysis, and the hazard ratio of the treatments was estimated using shared frailty models with a gamma distribution, which considered the patient as a cluster. There were no significant differences among treatments compared to sealants. After 18months, the use of a CO2 laser with or without acidulated fluorides was shown to be effective in preventing caries on the occlusal surface of partially erupted permanent first molars in children at high risk for caries.

Effects of Fluoride on NiTi Orthodontic Archwires: An X-ray Diffraction Study:

Objective: To explore the changes in nickel-titanium (NiTi) archwires after exposure to fluoride-containing acetic acid solutions. Materials and methods: Preformed rectangular NiTi wires were immersed in either an acidulated fluoride solution, a neutral fluoride solution or distilled water (control) for 1.5 hours at 37°C. After immersion, the unloading force values at four deflection points were measured by three-point bending test. Scanning electron microscopy and X-ray diffraction analysis were also performed to characterize the effects of the fluoride exposure on the wire. Results: Unloading force values of NiTi orthodontic wires were significantly decreased after exposure to both fluoride solutions (p < 0.001). Corrosive changes in surface topography were observed for both fluoride solutions. Wires exposed to acidic fluoride appeared as more severely affected. X-ray diffraction analysis showed no change in crystal lattice of NiTi wires in both solutions. Conclusion: The results suggest that using topical fluoride agents with NiTi wire could decrease the functional unloading mechanical properties of the wire and contribute to prolonged orthodontic treatment.

Microhardness of bovine enamel after different fluoride application protocols.

The aim of the present study was to evaluate microhardness, mineral recovery and the enamel surface after the application of topical fluoride to artificial dental caries. Twenty-five bovine enamel blocks were prepared for artificial caries-like lesions and randomly divided into five groups (n=5): untreated (C control), 1.23% acidulated phosphate fluoride gel (APG), 2% neutral fluoride gel (NFG), 1.23% acidulated fluoride mousse (AFM) and fluoride varnish (5% Duraphat, DFV). Knoop microhardness (KHN) was evaluated after 7 and 14 days of treatment as well as 1 week after 28 days of treatment. Electron and confocal microscopy and energy dispersive spectroscopy were performed. KHN data were treated with two-way ANOVA (material×time) and Tukey's test at a 5% significance level. Differences were found among groups over time (p<0.001). Microhardness varied after 7 and 14 days of treatment and remained stable 1 week after 28 days of treatment. Mineral recovery and enamel topography varied among groups, with the fluoride varnish achieving the most uniform topography.

Influence of Ultrapulsed CO2 Laser, before Application of Different Types of Fluoride, on the Increase of Microhardness of Enamel In Vitro.

Objective To evaluate the influence of ultrapulsed CO2 laser in combination with commercial fluoride products in order to verify the increase of microhardness of artificial enamel caries lesions. Materials and Methods Bovine enamel specimens were prepared, and artificial enamel caries lesions were created. Teeth were randomly divided into 5 groups (n=10): treated with laser (L), laser + neutral fluoride gel 2% (LNF), laser + acidulated phosphate fluoride gel 1.23% (LAFG), laser + acidulated fluoride mousse 1.23% (LAFM), and laser + fluoride varnish 5% (LFV). Microhardness was evaluated at baseline, after caries induction, after CO2 laser irradiation + fluoride treatment in the 1st week, and after fluoride treatment at 3rd and 5th week. Results There was a decrease in microhardness in all groups after artificial enamel caries lesion formation; no increase in microhardness was found in the first and third weeks in all groups (p > 0.05). In the fifth week, an increase in microhardness occurred in all groups (p < 0.05). Conclusion Although CO2 laser irradiation in combination with different commercial fluoride products was capable of increasing microhardness on enamel caries lesions in bovine tooth enamel it is necessary to confirm these results by testing the isolated effect of fluoride on enamel surface microhardness. Also, although microhardness was higher in the fluoride varnish group than in the other groups in the fifth week it is not possible to discard the best effect of fluoride varnish treatment on absence of artifacts that may occur with the other fluoride treatments. Clinical Relevance In order to prove that CO2 laser may contribute to an increase in microhardness when applied to enamel lesions in combination with different commercial fluoride products it is necessary to conduct additional studies. Also, higher microhardness of fluoride varnish group should be carefully considered.

Wear resistance and compression strength of ceramics tested in fluoride environments

Dental ceramics have been widely used because of aesthetic, but wear is still questioned. There are relates that ceramic surface is prone to degradation by acidulated fluoride, that can increase wear rates. The aim of this study was to evaluate the effect of neutral and acidulated fluoride gel, used as preventive agents for professional use, at wear and compression strength of dental ceramics IPS e.max ZirPress (ZIR), IPS Empress Esthetic (EMP) e IPS Inline POM (POM). For this, 30 crowns and 30 disks were obtained by heat-pressing. Crowns and disks were submitted to two-body wear test at machine of mechanical loading, simulating occlusion, lateral movement and disocclusion. It was performed 300,000 cycles at 1Hz frequency under 20N load, to simulate 1 year of mastication. Samples were totally immersed during the test and were divided into three groups according to the gel used for immersion (n=10): control, neutral (sodium fluoride 2%) and acidulated (acidulated phosphate fluoride 1.23%). Samples (crowns and disks) were analyzed for vertical height loss after the test using, respectively, profile projector and stereomicroscope. Roughness of worn surface of crowns and disks was evaluated by laser confocal microscopy. Data of height loss and roughness were evaluated by two-way ANOVA and Bonferroni's test. A crown/disk of each group was analyzed by scanning electronic microscopy. After wear resistance tests, crowns were cemented to their abutments and submitted to compressive load at 30° angulation and 1mm/min speed. Type of failures was compared by qui-square test. Ceramic EMP worn less while ZIR worn more. Control gel worn more at crowns while acidulated gel worn more at disks. Surface roughness of samples tested at acidulated gel was significantly lower. Type of failures found at compression resistance tests was affected by ceramic type, but not by gel used. The results suggest that ceramic and fluoride gel affect wear and roughness of worn surface while type of failure is only affected by ceramic.

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

Evaluation of acidulated dentifrice influence on fluoride releasing from glass-ionomer cements

Objective: To evaluate the acidulated dentifrice influence on fluoride releasing from glass-ionomer cements. Methods: 27 specimens were constructed, divided into 3 groups: G1 (Maxion - R), G2 (Ketac Molar 3M/ESPE) and G3 (Vittremer 3M/ESPE), and subdivided into 3 subgroups (n = 3): A (exposure to acidulated fluoride dentifrice – pH 4.5 / 7h / 37 oC), B (exposure to non-acidulated fluoride dentifrice / 7h / 37 oC), C (control - exposure to artificial saliva). After exposing, the specimens were immersed into artificial saliva and the fluoride releasing measured at the following time periods: 1 to 14 days. Data were subjected to analysis of variance using the Statistical Package for Social Science (SPSS). ANOVA test was applied with level of significance of 5% to compare the means and the behavior of each material. Results: The exposure to acidulated dentifrice showed fluoride releasing means values (ppm/mm2) that varied from 1 and 14 days : G1A (0.269 to 0.204); G2A (0.394 to 0.038); G3A (0.080 to 0.123). The relationship among the G1 subgroups at T1 and G3 subgroups at T1 and T14 was statistically significant. Conclusion: The acidulated dentifrice positively influenced on fluoride releasing of hybrid GIC but not on that of conventional GICs.Keywords: Glass-ionomer cement; Fluoride releasing; Acidulated dentifrice.

Influence of CO2 (10.6 μm) and Nd:YAG laser irradiation on the prevention of enamel caries around orthodontic brackets

One possible undesirable consequence of orthodontic therapy is the development of incipient caries lesions of enamel around brackets. The aim of this study was to compare the effects of CO2 (λ = 10.6 μm) and Nd:YAG (λ = 1,064 nm) lasers associated or not with topical fluoride application on the prevention of caries lesions around brackets. Brackets were bonded to the enamel of 65 premolars. The experimental groups (n = 13) were: G1--application of 1.23% acidulated fluoride phosphate gel (AFP, control); G2--Nd:YAG laser irradiation (0.6 W, 84.9 J/cm(2), 10 Hz, 110 μs, contact mode); G3--Nd:YAG laser irradiation associated with AFP; G4--CO2 laser irradiation (0.5 W, 28.6 J/cm(2), 50 Hz, 5 μs, and 10 mm focal distance); and G5--CO2 laser irradiation associated with AFP. Quantitative light-induced fluorescence was used to assess enamel demineralization. The data were statistically compared (α = 5%). The highest demineralization occurred in the Nd:YAG laser group (G2, 26.15% ± 1.94). The demineralization of all other groups was similar to that of the control group. In conclusion, CO2 laser alone was able to control enamel demineralization around brackets at the same level as that obtained with topical fluoride application.

Influence of Er,Cr:YSGGLaseron CaF2-like products formation because of professional acidulated fluoride or to domestic dentifrice application

This study evaluated the synergy of professional acidulated fluoride gel (APF) or fluoridated dentifrice application combined with Er,Cr:YSGG laser irradiation on the formation of CaF2 -like products (CaF2 ), in vitro. Thus, 272 bovine enamel slabs were randomly distributed among eight groups: G1: untreated enamel; G2: treated with fluoridated dentifrice (NaF, 1,100 μgF/g); G3: treated with acidulated phosphate fluoride gel (APF, 1.23% F(-) ); G4: irradiated with Er,Cr:YSGG laser at 8.5 J/cm(2) ; G5 and G6: combination of pre-irradiation with Er,Cr:YSGG followed by dentifrice or APF application, respectively; G7: combination of dentifrice application followed by Er,Cr:YSGG irradiation; G8: combination of APF application followed by Er,Cr:YSGG irradiation. After treatments, samples were evaluated by scanning electron microscopy, and the content of CaF2 was determined by an ion specific electrode. Both APF and dentifrice application promoted the formation of CaF2 on enamel, whereas Er,Cr:YSGG irradiation promoted an increase of roughness of the enamel, increasing the surface area. Laser irradiation before fluoridated products increased the content of CaF2 formed when compared to groups that APF or dentifrice were applied isolated. However, the content of CaF2 formed when irradiation was performed after APF or dentifrice was not statically significant when compared to the control groups. In conclusion, Er,Cr:YSGG laser increases the formation of CaF2 on enamel when the irradiation is performed before the application of APF or dentifrice. The association of laser with APF is most promissory for caries prevention because of the higher concentration of CaF2 formation and also the chemical changes promoted by laser irradiation demonstrated in literature.

Comparative evaluation of acidulated sodium fluoride gel 0.33% (iontophoresis) with hydroxy-ethyl methacrylate with glutaraldehyde as a desensitizing agent in dentinal hypersensitivity patients: A clinical study

Background: Iontophoresis is a method of electrically transporting ionic particles into the hard and soft-tissues to achieve therapeutic benefits to manage dentinal hypersensitivity. Aim: The primary aim of the following study is to evaluate and the secondary aim is to compare the efficacy of two different desensitizing agents in moderate and severe dentinal hypersensitivity patients using acidulated sodium fluoride (NaF) gel 0.33% using iontophoretic unit and hydroxyl-ethyl methacrylate with glutaraldehyde (HEMA-G), in reducing the dentinal hypersensitivity. Materials and Methods: The hypersensitive teeth were identified by the patient and verified by the light stroke of dental explorer along the cervical area of all teeth. A total of 40 Subjects fulfilling the inclusion criteria were evaluated using stimuli. Responders were recorded with the verbal rating scale scores and divided into two groups: Group 1 (moderate dentinal hypersensitivity) and Group 2 (severe dentinal hypersensitivity). Each group was further subdivided into Subgroup A (treated with Iontophoresis) and Subgroup B (treated with 35% hydroxy-ethyl methacrylate and 5% glutaraldehyde).The teeth were evaluated after 2 weeks and 1 month from baseline. Results: The results were obtained using analysis variance and Student t-test using Graph Pad Prism 5.0 version and SPSS 17.0 version Software for Windows 7 software for Windows and was not significant, reduction in dentinal hypersensitivity was observed with both HEMA-G and Iontophoresis, with a remarkable reduction with Iontophoresis at the end of 2 weeks and 1 month. Conclusion: Desensitizing agents HEMA-G and 0.33% acidulated NaF gel, were both equally effective in causing immediate relief in dentinal hypersensitivity, but Iontophoresis (0.33% NaF) was found to be comparatively better than HEMA-G desensitizer for long-term relief.

EQCM Analysis of Titanium Corrosion in Peroxide- or Fluoride-Containing Solutions

Although offering superior resistance to corrosion, titanium is unable to withstand discoloration with exposure to peroxide or fluoride. The mechanism of this discoloration, however, remains to be clarified. The purpose of this study was to investigate the mechanism underlying discoloration of titanium with immersion in peroxide- or fluoride-containing solutions based on electrochemical quartz crystal microbalance (EQCM) analysis. A 9-MHz titanium-deposited quartz crystal was used as for the electrodes. Four test solutions were prepared for immersion of the electrodes: 154 mM (0.9%) NaCl; 150 mM H2O2+154 mM NaCl (pH=4 by addition of lactic acid); 150 mM H2O2+154 mM NaCl (pH=8 by addition of sodium hydroxide solution); and 48 mM (0.2%) NaF+154 mM NaCl (pH=5.0 by addition of lactic acid). A WinEchem electrochemistry software-controlled quartz crystal analyzer (QCA922) and the Potentiostat/Galvanostat (Princeton Applied Research) on Windows XP were used to measure concurrently the resonance frequency and potential of the electrodes. The EQCM data differed among solutions. In the acidulated fluoride-containing solution, the electrode showed lower open circuit potential and a gradual increase in electrode frequency, indicating a loss of mass by titanium dissolution. In the peroxide-containing solution, although open circuit potential showed no marked difference, electrode frequency showed a gentle decrease in acidic solution, indicating a gain in mass by oxidation; but an increase in alkaline solution, indicating a loss of mass by dissolution. These results confirmed that exposure to acidulated fluoride- or alkaline peroxide-containing solutions causes dissolution-induced discoloration, while that to acidulated peroxide-containing solutions resulted in the formation of an oxide film together with discoloration.

Effect of Fluoride Prophylactic Agents on the Mechanical Properties of Nickel-Titanium Wires: An in vitro Study

Titanium-based alloys have high corrosion resistance because they form a thin, stable oxide layer. Nevertheless, fluoride prophylactic agents can cause corrosion and associated discoloration of titanium-based orthodontic wires. Objective: The purpose of this investigation was to study the effects of fluoride prophylactic agents on the mechanical properties of nickeltitanium (NiTi) and copper-nickel-titanium (Cu-NiTi) orthodontic archwires. Materials and methods: Preformed rectangular NiTi and Cu-NiTi wires were immersed in either an acidulated fluoride agent, a neutral fluoride agent, or distilled water (control) for 1.5 hours at 37°C. After immersion, the loading and unloading elastic modulus and yield strength of the wires were measured with a 3-point bend test in a water bath at 37°C, in accordance with the criteria in the current American National Standard/ American Dental Association Specification No. 32 for Orthodontic Wires (2000). Scanning electron microscopy was also used to characterize the effects of the fluoride treatment on the wire topography. Results: The results showed that unloading mechanical properties of both the NiTi orthodontic wires were significantly decreased after exposure to both fluoride agents [one-way analysis of variance (ANOVA) and Dunnett’s post-hoc,  = 0.05]; corrosive changes in surface topography were observed for both wires, with Phos-Flur gel creating more detrimental effects. Conclusion: The results suggest that using topical fluoride agents with NiTi wire could decrease the functional unloading mechanical properties of the wire and contribute to prolonged orthodontic treatment.

The effect of fluoride therapies on the morphology of bleached human dental enamel

The aim of this in vitro study was to evaluate qualitatively the surface morphology of enamel bleached with 35% hydrogen peroxide (HP) followed by application of fluoridated agents. Forty intact pre molars were randomly distributed into four groups (n = 10), treated as follows: Group I (control group) remained stored in artificial saliva at 37 °C, Group II - 35% HP; Group III - 35% HP + acidulated fluoride (1.23%) and Group IV - 35% HP + neutral fluoride (2%). The experimental groups received three applications of bleaching gel and after the last application all specimens were polished. This procedure was repeated after 7 and 14 days, and during the intervals of applications, the specimens were stored in artificial saliva at 37°C. Scanning electron microscopy (SEM) analysis showed superficial irregularities and porosities to varying degrees in bleached enamel compared to control group. Sample evaluation was made by attributing scores, and data were statistically analyzed using Kruskal-Wallis and Dunn tests (P < 0.05). SEM qualitative investigation demonstrated that 35% hydrogen peroxide affected human dental enamel morphology, producing porosities, depressions, and superficial irregularities at various degrees. These morphological changes were higher after the application of 1.23% acidulated fluoride gel.

Cariostatic effect of fluoride-containing restorative materials associated with fluoride gels on root dentin

Secondary caries is still the main cause of restoration replacement, especially on the root surfaceObjectiveThis in vitro study evaluated the cariostatic effects of fluoride-containing restorative materials associated with fluoride gels, on root dentin.Materials and MethodsA randomized complete block design was used to test the effects of the restorative systems, fluoride regimes and the interactions among them at different distances from restoration margins. Standardized cavities were prepared on 240 bovine root specimens and randomly assigned to 15 groups of treatments (n=16). Cavities were filled with the following restorative materials: Ketac-Fil (3M-ESPE); Vitremer (3M-ESPE); Dyract/Prime & Bond NT (Dentsply); Charisma/Gluma One Bond (Heraeus Kulzer) and the control, Z250/Single Bond (3M-ESPE). The specimens were subjected to a pH-cycling model designed to simulate highcaries activity. During the cycles, 1.23% acidulated phosphate fluoride, 2.0% neutral sodium fluoride or deionized/distilled water (control) was applied to the specimens for 4 min. The surface Knoop microhardness test was performed before (KHNi) and after (KHNf) the pH cycles at 100, 200 and 300 mm from the margins. Dentin microhardness loss was represented by the difference in initial and final values (KHNi - KHNf). Data were analyzed by Friedman's and Wilcoxon's tests, ANOVA and Tukey's test (α=5%).ResultsThe interaction of restorative systems and topical treatments was not significant (p=0.102). Dentin microhardness loss was lowest closer to the restoration. Ketac-fil presented the highest cariostatic effect. Vitremer presented a moderate effect, while Dyract and Charisma did not differ from the control, Z250. The effects of neutral and acidulated fluoride gels were similar to each other and higher than the control.ConclusionConventional and resin-modified glass ionomer cements as well as neutral and acidulated fluoride gels inhibit the progression of artificial caries adjacent to restorations. The associated effect of fluoride-containing restorative materials and gels could not be demonstrated.

Effectiveness of a Preventive Educational Programme on the Oral Health of Preschool Children

The aim of the study was to evaluate the impact of a preventive-educational programme in a group of preschool children. The study's population group comprised 58 four-year-old children, with a mean age of 4.17 +/- 0.27. Plaque index and gingival index were determined, and a dental examination was performed. The children were randomly assigned to one of two groups: experimental and control. The experimental group received the educational component of the programme which was for children, parents and teachers. The preventive programme was applied to both groups and included topical application of 1.23% acidulated fluoride phosphate, pH 3.5, every 6 months. Outcomes were measured on day 8 and after 6 and 12 months under similar conditions to those at baseline. Results showed a significant decrease in gingival index and plaque index values and no significant increase in decay in the experimental group. The control group showed a significant increase in gingival index, plaque index, and decayed surfaces.

Mechanical Properties and Surface Characterization of Beta Titanium and Stainless Steel Orthodontic Wire Following Topical Fluoride Treatment

To study the effect of fluoride prophylactic agents on the loading and unloading mechanical properties and surface quality of beta titanium and stainless steel orthodontic wires. Rectangular beta titanium and stainless steel wires were immersed in either an acidulated fluoride agent, a neutral fluoride agent, or distilled water (control) for 1.5 hours at 37 degrees C. After immersion, the loading and unloading elastic modulus and yield strength of the wires were measured using a 3-point bend test in a water bath at 37 degrees C. A one-way analysis of variance and Dunnett's post hoc, alpha = .05, were used to analyze the mechanical testing data. Scanning electron microscopy was also used to qualitatively evaluate the wire topography as a function of the fluoride treatments. Unloading mechanical properties of beta titanium and stainless steel wires were significantly decreased (P <or= .05) after exposure to both fluoride agents. Corrosive changes in surface topography were also observed after exposure to both the neutral and the acidulated phosphate fluoride agents. The results suggest that using topical fluoride agents with beta titanium and stainless steel wire could decrease the functional unloading mechanical properties of the wires and potentially contribute to prolonged orthodontic treatment.

Effect of an acidulated fluoride etchant on bonding between titanium and two luting materials

Adhesive bonding between resin and titanium is useful for resin-bonded prostheses. The purpose of this study was to investigate the efficacy of an etchant, consisting of ammonium hydrogen fluoride (AHF) and phosphoric acid (PA), in titanium bonding. Cast specimens of commercially pure titanium were air-abraded with alumina and etched for 30 s, after which a primer (ALP) was applied. An acrylic rod was bonded to the specimen with one of the two luting agents being examined (Super-Bond QUICK and Panavia F2.0). Shear bond strengths were determined following 10,000 thermocycles. When Panavia F2.0 was applied, neither the etchant nor the ALP primer showed significant effect on bond strength. The postthermocycling bond strength of Super-Bond QUICK was significantly improved with the use of an etchant and ALP primer. Although microscopic observation revealed that considerable numbers of submicron pits were created on the specimens etched using AHF with PA, no significant difference in bond strength was detected in the application of AHF, with or without PA. The present findings suggested that the improved bonding durability was due to the micromechanical retention between the resin and the microscopically roughened titanium surface.

Effect of APF gel on micromorphology of resin modified glass–ionomer cements and flowable compomers

The purpose of this study was to evaluate the surface micromorphology of resin modified glass-ionomer cements and flowable compomers. In the study two resin modified glass-ionomers and two flowable compomers were used to prepare standardized 20 cylinderic samples. Samples were divided into four groups. Surface treatments with APF gel for experimental groups (group B,C,D) or distilled water as a control (group A) were performed four times. In group B, only APF gel was applied. In group C, after the APF gel application, the samples were immersed into the demineralizing and remineralizing solutions. In group D, before the APF gel application, the buffer solution was applied. The examinations of the surface micromorphology of the materials were made by using scanning electron microscope (SEM). Results showed that in group B all of the materials except Compoglass Flow, and in group C all of the materials showed erratic behaviours. In group D, severe erratic effect (score 2) was obtained on the surfaces of Vivaglassliner and Dyract Flow, and for the others score 1 signals were found. The moderate degradation was obtained by applying of only APF gel on the surfaces of both material groups. The addition of pH circulation caused increasing of micromorphologic changes on the surfaces of all materials. The effect of application of buffer solution on the surfaces before APF gel changed according to the materials. If acidulated fluoride gel is preferred for prophylactic therapy in patients' mouth, for the success, either buffer or neutral fluoride have to be applied on the restored teeth by resin based materials before acidulated fluoride application.