Acidulated Phosphate Fluoride Application Research Articles

Effect of Nd:YAG Laser and Acidulated Phosphate Fluoride on Bovine and Human Enamel Submitted to Erosion/Abrasion or Erosion Only: An in Vitro Preliminary Study

The aim of the present in vitro study was to evaluate, using two different methodologies, the effectiveness of pulsed Nd:YAG laser irradiation associated with topical acidulated phosphate fluoride (APF) for preventing enamel erosion and structure loss under regimes of erosion and abrasion or erosion only. An increased incidence of noncarious lesions (erosion and abrasion) has been observed, consequently new preventative therapies have been proposed. Two different methodologies were performed. For the first, 100 bovine crowns were submitted to four different treatments (n = 25): no treatment (control), 4 min application of APF, Nd:YAG laser irradiation (1 W, 100 mJ, 10 Hz, 141.5 J/cm(2)), and Nd:YAG laser irradiation + 4 min of APF. After the specimens were exposed to citric acid (2% w/v; 30 min), they were submitted to 5000 brushing cycles. Specimen mass was measured before and after the treatments. For the second methodology, 20 human crowns were embedded in acrylic resin and cut surfaces were exposed and polished. The specimens were divided into four groups (n = 10): no treatment (control), APF for 4 min, Nd:YAG laser irradiation (1 W, 100 mJ, 10 Hz, 125 J/cm(2)), and Nd:YAG laser irradiation + APF. The samples were then immersed in citric acid (2% w/v; 90 min). Vickers hardness was obtained before and after the treatments. The Nd:YAG laser irradiation + APF (bovine and human enamel) was more effective and yielded statistically significant results for surface microhardness and enamel wear. Nd:YAG laser irradiation associated with APF reduced bovine enamel wear and human enamel softening when samples were submitted to a regime of erosion and abrasion or erosion only in vitro.

Nd:YAG laser in caries prevention: A clinical trial

It is widely known that Nd:YAG can increase enamel resistance to demineralization; however, there are no studies that report the application of Nd:YAG associated with topical application of fluoride in vivo. The aim of this study was to evaluate the effects of the Nd:YAG laser, when associated with the topical application of acidulated phosphate fluoride (APF), for preventing enamel demineralization in vivo. A double-blind crossover experimental design was used, in which 121 teeth of 33 volunteers were selected. In all volunteers, the right side teeth were selected for Nd:YAG laser+APF application (lased group) and the left side teeth were kept as control group (only APF application). Nd:YAG laser was applied at 60 mJ/pulse, at a repetition rate of 10 Hz and fluence of 84.9 J/cm(2); after that, topical APF was applied for 4 minutes. Recalls were made after 1 year in order to evaluate the formation of white-spot lesions or caries cavities. After 1 year, this in vivo experiment showed a reduction of 39.2% in caries incidence in lased group when compared with the control. The number of white-spots or caries cavities decreased significantly (P = 0.0043) in the Nd:YAG laser group; the formation of white-spots was significantly less (P = 0.0031) when compared with the number of lesions in the control group. Combined Nd:YAG laser and topical fluoride treatment was effective for reducing the incidence of caries in vivo.

Surface roughness and gloss of indirect composites etched with acidulated phosphate fluoride solution

Objective. To evaluate the surface characteristics of indirect composites etched with acidulated phosphate fluoride (APF) solution. Material and methods. APF solution was applied to specimens of six composite materials. The surface morphological change was measured with a confocal laser scanning microscope. Gloss measurement and scanning electron microscope (SEM) observation were also performed. Results. The APF-treated surface showed various patterns due to the difference in the filler incorporated in each composite. The surface properties could be evaluated precisely from the surface roughness parameters. The arithmetical mean deviation of roughness profile (Ra) parameter of the specimens treated with APF solution was higher than those of the specimens untreated with APF, except New Meta Color Infis (IF). The difference in etching influence of each composite material was shown conclusively in the maximum height of the profile (Rz) parameter. Gradia (GR) and Gradia Forte (GF) were etched three times more deeply than that of IF categorized microfilled composite. The mean width of the profile element (RSm) decreased significantly after APF treatment, except in IF. Gloss was reduced apparently in all materials, indicating that gloss reduction was sensitive to slight surface changes. Conclusions. Specific filler particles of prosthodontic composite materials were etched by APF application. The surface roughness parameters, such as Rz and RSm, properly described various surface topographic features. Gloss was strongly correlated to surface roughness, as defined by these parameters, and especially to the initial change of surface roughness.

Effect of APF gel application time on enamel demineralization and fluoride uptake in situ

This in situ crossover and blind study was conducted to investigate the effect of professional acidulated phosphate fluoride (APF) gel application time on the subsequent inhibition of enamel demineralization. During 3 phases of 28 days each, 15 volunteers wore palatal appliances containing 4 enamel blocks, which were subjected to 3 treatment groups: not treated (control) and pre-treated with APF gel for 1 or 4 min. Dental plaque was allowed to accumulate on the blocks and the appliances were immersed in 10% sucrose solution 3 times a day simulating a cariogenic challenge. After each phase, the blocks were removed to evaluate enamel demineralization and concentration of fluoride (F) remaining after the cariogenic challenge. F formed on enamel was determined in additional enamel blocks subjected only to APF gel application. APF gel was efficient in reducing enamel demineralization (p<0.05), irrespective of the application time (p>0.05). Also, the concentration of the F formed and retained on enamel was significantly higher after APF gel application (p<0.05), but the effect of time of application was not statistically significant (p>0.05). The results suggest that APF application for either 1 or 4 min is equally efficient to increase F concentration in enamel and reduce enamel demineralization.

Fluoride uptake and acid resistance of enamel irradiated with Er:YAG laser

This study evaluated the resistance to demineralization and fluoride incorporation of enamel irradiated with Er:YAG. A total of 110 bovine teeth were selected and divided into eight groups: unlased, 37% phosphoric acid, and samples irradiated with the Er:YAG laser at several fluences (31.84 J/cm(2), 25.47 J/cm(2), 19.10 J/cm(2), 2.08 J/cm(2), 1.8 J/cm(2), and 0.9 J/cm(2)). The application of acidulated phosphate fluoride was performed after treatments. All samples were immersed in 2 ml of 2.0 M acetic-acetate acid solution at pH 4.5 for 8 h, and fluoride, calcium, and phosphorus ions dissolved were analyzed by atomic absorption spectrometry and spectrophotometry. The phosphoric acid and 31.84 J/cm(2) groups presented the lowest dissolution of calcium and phosphorus ions. Higher fluoride incorporation was observed on 1.8 J/cm(2) and 0.9 J/cm(2) groups. Based on these results, Er:YAG laser was able to decrease acid dissolution and increase fluoride uptake and can be a promissory alternative for preventive dentistry.

The effect of acidulated phosphate fluoride application on dental enamel surfaces hardness

Enamel demineralization by acid is the first step of caries process. It has recently been shown that acidulated phosphate fluoride (APF) can maintain the hardness of enamel surface. The aim of this study was examine the effect of APF application in the hardest of enamel surface. Fifty extracted teeth were cut at their crown, 40 teeth were taken randomly then divided into 4 groups, group 1 as the control, group 2 was treated with APF for 1 minute, group 3 for 4 minutes and group 4 for 7 minutes, then all the samples were washed with demineralized water. To see the effect of APF, all of the samples were soaked in lactic acid demineralization solution with pH 4,5 for 72 hours., the hardness of the surfaces of those samples before and after the treatment was measured by Micro Vickers Hardness Tester. The data were analyzed using One-Way ANOVA and LSD tests. In conclusion, 1.23% APF gel can reduce higher enamel demineralization.

Effects of low power red laser on induced-dental caries in rats

Objective The purpose of this study was to investigate the effects of low power red laser associated with acidulated phosphate fluoride on the development of induced-dental caries in rats. Design Dental caries were induced in molars of 40 rats divided into five groups: control group (CG), the teeth were not submitted to any treatment; laser group (LG), teeth were irradiated with a low power red laser (LPRL), power of 30 mW and dose of 5 J/cm 2; fluoride group (FG), teeth were treated with topical acidulated phosphate fluoride (APF) 1.23% applied for 4 min; laser + fluoride group (LFG), teeth were irradiated with LPRL followed by APF; fluoride + laser group (FLG), teeth were treated with APF followed by LPRL. The animals were killed after 48 days, and the first and second molars were extracted to analyze the caries lesion area, microhardness, and calcium and phosphorus ratio. Results There were no statistical differences among FG, LFG, and FLG regarding to caries area and microhardness, although the caries area were smaller in LFG. Ca/P ratio did not show significant differences among all groups. Conclusions Although LPRL before APF application appeared to diminish the caries progression, LPRL did not present any additional benefit compared with acidulated phosphate fluoride on the prevention of induced-dental caries in rats.

Effect of Rinsing with Water Immediately after APF Gel Application on Enamel Demineralization in situ

This double-blind crossover in situ study evaluated the effect of rinsing with water immediately after the application of acidulated phosphate fluoride (APF) on enamel demineralization. APF application was followed by: no rinsing or consuming of liquids or solids for the next 30 min; immediately washing with water jet or drinking of a glass of water. All treatments showed a statistically significant decrease in enamel mineral loss compared to the control (p < 0.05), but the differences among treatments were not significant (p > 0.05). The data suggest that the recommendation of asking patients to refrain from drinking water following professional APF application does not seem to have an influence on the anticaries effect of fluoride.

The Effect of a Bi-annual Professional Application of APF Foam on Dental Caries Increment in Primary Teeth: 24-month Clinical Trial

The purpose of this study was to evaluate the effect of a bi-annual professional application of acidulated phosphate fluoride (APF) foam on caries increment in the primary dentition over a two-year period in the People's Republic of China. In a double-blind, cluster-randomized, placebo-controlled trial, 392 children aged 3-4 years from 15 classes were randomly assigned to two groups on a school class basis. The experimental group (8 classes) received a bi-annual APF foam application, and the control group (7 classes) received the placebo. The mean increment of dmfs in the experimental group was 24.2% lower than that in the control group (p < 0.05). The significant caries reduction was observed on approximal surfaces in the experimental group compared with the control group (p < 0.01), but there were no differences on occlusal surfaces (p > 0.05). A bi-annual professional application of APF foam was effective in reducing the increment of dental caries in the primary teeth.

Effect of Er:YAG laser on CaF2 formation and its anti-cariogenic action on human enamel: an in vitro study.

The objective of this study was to evaluate the effect of Er:YAG laser on the formation of CaF(2), after the application of acidulated phosphate fluoride (APF), and its influence on the anti-cariogenic action in human dental enamel. Er:YAG laser was designed to promote ablation of the enamel. However, the possibility of using this energy to increase the enamel's resistance to caries has hardly been explored, and neither has its interaction with the use of fluorides. One hundred and twenty blocks of enamel were allocated to four groups of 30 blocks each: (1) C, control group; (2) Er:YAG, laser; (3) APF; and (4) Er:YAG+APF. Of these, 80 blocks were submitted to pH cycling for 14 days. In the other 40 blocks, fluoride (CaF(2)) was measured before cycling. After pH cycling, surface microhardness (SMH), microhardness in cross-section (converted to mineral contents % vol. min.), and fluoride after cycling (40 blocks) were also determined. SMH decreased in all groups. The control group showed the highest decrease, and Er:YAG+APF showed the lowest decrease (p < 0.05). Groups APF and Er:YAG showed the same results (p > 0.05). Mineral content at depths 10, 20, and 40 microm was lower in the control and Er:YAG groups, and higher in groups APF and Er:YAG+APF. CaF(2) (microgF/cm(2)) deposited before pH cycling was higher in the APF group when compared to the Er:YAG+APF group. Control and Er:YAG groups showed the lowest values (p > 0.05). It was concluded that Er:YAG laser influenced the deposition of CaF(2) on the enamel and showed a superficial anti-cariogenic action, but not in depth.

Bond strength with APF applied after acid etching

One tenet of successful orthodontic therapy is to complete treatment without decalcification, hypocalcification, or discoloration of the natural dentition. Fluoride application has been shown to reduce demineralization of enamel. The purpose of this study was to see if fluoride could be incorporated into enamel before orthodontic bracketing without adversely affecting bond strength. Forty extract adolescent human premolars were randomly divided into two equal groups with 20 teeth each. Group 1 served as control group, and group 2 (experimental) was immersed in 1.23% acidulated phosphate fluoride for 4 minutes after acid etching. The buccal surfaces of all 40 teeth were then bonded with the same type of metal bracket and debonded with an Instron machine. The debonding interface was observed with scanning electron microscopy (SEM). The mapping was calculated with energy dispersive x-ray spectrometry. The results showed that the bond strength of group 1 was significantly greater than that of group 2. The enamel detachment (enamel fracture) was found in the experimental group only. Although the application of acidulated phosphate fluoride to a tooth can prevent dental decay or decalcification, the bond strength decreases and enamel detachment is found after debonding. The result shows that the application of acidulated phosphate fluoride after acid etching enamel has an adverse effect on orthodontic bond strength of human enamel.(Am J Orthod Dentofacial Orthop 1998;114:510-3)

歯ブラシを用いたフッ化物ゲル歯面塗布法の口腔内残留フッ素量

Oral fluoride retention was studied following the topical application of acidulated phosphate fluoride (APF) gel with a toothbrush. Forty-four children (aged 1.5years) were treated by 3 hygienists. The amount of APF gel prepared for each child was 0.81±0.09g (Mean±SD). The amount of retained fluoride was 2.09±0.07mg. The amount of retained fluoride per body weight was 0.19±0.06mg ranging from 0.07 to 0.31mg. This fluoride application technique using a toothbrush was easier than using a tray, and was accepted well even by younger children.The results show that children do not ingest toxic doses of fluoride when this application technique is employed.

Combined effects of laser and fluoride on acid resistance of human dental enamel.

Specimens of human dental enamel were topically applied with solutions of sodium fluoride (NaF) or acidulated phosphate fluoride (APF) before and after laser irradiation. APF application after laser irradiation caused a remarkable increase in acid resistance of the enamel, while APF application before laser irradiation showed a lesser effect, similar to either APF treatment alone or laser irradiation alone. These results were consistent with observations made using a scanning electron microscope. APF application after laser irradiation produced a greater fluoride uptake in the enamel than APF application before laser irradiation, as shown by electron probe microanalyzer. NaF application caused lesser acid resistance and lesser fluoride uptake than APF application, even when the enamel was treated with laser irradiation.

Effects of DCPD/APF application and prolonged exposure to fluoride on caries-like lesion formation in vitro.

The ability of a topical fluoride regimen consisting of a 4-min application of a saturated dicalcium phosphate dihydrate (DCPD) solution followed by a 4-min application of 1.23% acidulated phosphate fluoride (APF) to inhibit caries-like lesion formation in sound enamel was compared to that of a 4-min application of APF. Following the applications, specimens were washed for 24 h in an inorganic wash solution or for 28 days in a wash solution containing 1 ppm fluoride. The mean overall lesion depth for specimens treated with APF and washed for 28 days was significantly greater than that for the group treated with DCPD/APF and washed for 28 days, and for the group treated with APF and washed for 24 h (p less than 0.05). For those specimens washed for 24 h, the mean width of the surface zone was greater (p less than 0.05) for the DCPD/APF group compared to the APF group.

フッ化チタンアンモニウム溶液によるエナメル質の耐酸性について

The purpose of this study was to investigate the contribution of fluoride and titanium uptake in powdered enamel to the acquisition of acid resistance.Experiments were made in vitro by treatment with solution of (NH4) 2 TiF6 (9000 ppm of F, pH 3.4) or APF (acidulated phosphate fluoride solution) for 3 minutes at 37°C with powdered enamel (particle size 70-140 μm), and 24-hour washing with synthetic saliva or 1M KOH solution was used to distinguish the soluble and permanently bound fluoride. Chemical analyses were performed to determine fluoride, titanium, calcium, and phosphorus. Acid solubility of enamel was evaluated to determine the calcium released from powdered enamel into acetate buffer (pH 4.5). The reaction products were identified by X-ray diffractometry.A large amount of fluoride uptake, most of it in the form of CaF2, was found after application of APF. Synthetic saliva or KOH washing removed most of the fluoride from APF treated enamel, but (NH4) 2 TiF 6-treated enamel had lower levels of fluoride uptake and higher retention after both washings. These facts indicated that a higher level of more permanently bound fluoride formed in (NH4) 2 TiF6-treated enamel.Titanium in (NH4) 2 TiF6-treated enamel was resistant to synthetic saliva washing, but the KOH wash caused a partial release of titanium.The acid solubility test of fluoride-treated enamel showed the same degree of acid resistance before and after synthetic saliva wash. However, the KOH wash decreased an acid resistance of both types of fluoride-treated enamel. A decrease of acid resistance in APF-treated enamel may contribute to the release of alkali-soluble fluoride such as CaF2. In the case of (NH4) 2 TiF6, a decrease of acid resistance might be related to the titanium concentration in enamel. The release of fluoride and titanium from (NH4) 2 TiF6-treated enamel into 1MKOH solution suggests a hydrolysis of titaniumfluoride compound, which forms an organometallic bond with the enamel protein called“glaze”, rather than a release of CaF2.As the results, it is suggested that glaze-like substance is soluble in strong alkali such as 1MKOH soluion but stable in acid circumstances, and controls acquisition of acid resistance of powdered enamel.

A combined approach to preventing dental caries in schoolchildren: caries reductions after one year

A prototype school-based dental program is being conducted in a low-middle-income, urban area, as a demonstration project to test the combined effect on dental caries of several preventive measures. Procedures include ingestion of fluoridated water (1.0 ppm), topical application of acidulated phosphate fluoride, application of a pit and fissure sealant, early detection of caries and restoration of affected teeth, and dental health education (oral hygiene and dietary counseling program). The four-year project began in early 1973. A group of 1,200 children in the first and sixth grades was randomly separated into a treatment and a comparison group. All children participate in a dental health education program and consume fluoridated water. Dental care is provided on site at 18 schools, with the use of two mobile vans, saving time and expense in school hours lost and transportation costs. A hygienist coordinates the oral hygiene and dietary programs in classrooms with the help of teachers trained in workshops. Supervised toothbrushing, flossing, and use of disclosing agents are carried on in the classrooms. First-year caries increment data in permanent teeth indicate a high degree of success. Occlusal surfaces of permanent teeth in children in the treatment group, contrasted to those in children in the comparison group, showed an average reduction in caries of 84%. The encouraging results obtained at the end of one year indicate that a school-based preventive dentistry program may have great potential for preventing and controlling dental caries in schoolchildren.

Preventing enamel decalcification during orthodontic treatment

One hundred thirty-two extracted premolar teeth were selected and divided into four equal groups. The first group of thirty-three teeth received a topical application of acidulated phosphate fluoride; the second group, a topical application of stannous fluoride; the third group, an application of a polymeric adhesive coating; the fourth group was left untreated to serve as a control. On each tooth a loosely fitted orthodontic band was cemented to place. After cementation, the band was broken to simulate a loose orthodontic band in vivo.The four groups of teeth were simultaneously immersed in a decalcifying gelatin and were left undisturbed for 11 weeks. The teeth were then removed and a record was made of the decalcification produced.A chi-square test was used to compare the teeth in each group to those in every other group. Compared to a control group of teeth, those teeth treated with polymeric adhesive coating, acidulated phosphate fluoride, or stannous fluoride produced a statistically significant reduction in decalcification of the tooth surfaces beneath loose orthodontic bands.For a one-application technique, the polymeric adhesive coating provided more protection against decalcification of teeth under loose orthodontic bands than did either acidulated phosphate fluoride or stannous fluoride.