Acidulated Phosphate Fluoride Application Research Articles

Influence of Er:YAG and ND:YAG laser irradiation and fluoride application on surface roughness and dentin surface wear after erosive challenge - An in vitro study.

To evaluate the effectiveness of Er:YAG and Nd:YAG laser on dentin hypersensitivity prevention, associated or not to acidulated phosphate fluoride (APF) after erosive challenge. 104 specimens were obtained from bovine dentine and divided into groups (n=13): G1: Er:YAG; G2: Er:YAG followed by application of APF; G3: application of APF followed by Er:YAG, simultaneously; G4: Nd:YAG; G5: Nd:YAG followed by application of APF; G6: application of APF followed by Nd:YAG, simultaneously; G7:application of APF; G8: untreated. The parameters for Er:YAG were:10s, distance of 4mm, water cooling flow of 2mL/min, 2Hz, 3.92J/cm2. For the Nd:YAG: 10s, distance of 1mm, without cooling, 10Hz, 70.7J/cm2. The erosive drink was a cola at 4°C, 3×/day for 1 minute, for 5 days. Roughness and wear analysis were done in confocal laser microscope. Data were statistically analyzed (α=0.05). As regards roughness, there was no statistically difference among the groups. The groups irradiated with Er:YAG had a volume loss lower. G6 showed higher values than the groups irradiated with Er:YAG and lower than the other groups. The other groups irradiated with Nd:YAG showed similar wear results to the control. The Er:YAG laser showed the lowest volume loss from wear analysis, suggesting the increased the acid resistance of dentin. Key words:Dentine sensitivity, Lasers, Sodium fluoride.

Remineralization effect of Er;Cr:YSGG laser irradiation with or without acidulated phosphate fluoride application on deciduous teeth enamel surface with induced white spot lesion. An in vitro study

Remineralization effect of Er;Cr:YSGG laser irradiation with or without acidulated phosphate fluoride application on deciduous teeth enamel surface with induced white spot lesion. An in vitro study

Inhibition of Citric Acid-Induced Dentin Erosion by an Acidulated Phosphate Sodium Monofluorophosphate Solution.

Sodium monofluorophosphate (Na2FPO3, MFP) is mainly used as an ingredient in fluoride-based dentifrices as it has a high safety profile, with one-third of the toxicity of sodium fluoride (NaF), as well as the ability to reach deep into the dentin. The purpose of this study was to assess the prevention of dentin erosion by MFP upon exposure to citric acid, which has a chelating effect, and to compare the effects to those of the conventional acidulated phosphate fluoride (APF) application method. Bovine dentin was used, and four groups were created: (i) APF (9000 ppmF, pH 3.6) 4 min group; (ii) acidulated phosphate MFP (AP-MFP, 9000 ppmF, pH 3.6) 4 min group; (iii) AP-MFP 2 min + APF 2 min (dual) group; and (iv) no fluoride application (control) group. Compared with the conventional APF application method, the application of AP-MFP was shown to significantly reduce substantial defects, mineral loss, and lesion depth; better maintain Vickers hardness; and promote the homogenous aggregation of fine CaF2 particles to seal the dentin tubules, enhancing acid resistance in their vicinity. The ΔZ value of the AP-MFP group was 2679 ± 290.2 vol% μm, significantly smaller than the APF group's 3806 ± 257.5 vol% μm (p < 0.01). Thus, AP-MFP-based fluoride application could effectively suppress citric acid-induced demineralization and could become a new, more powerful, and biologically safer professional-care method for preventing acid-induced dentin erosion than the conventional method.

Gloss and surface roughness of pre-polymerized composite materials designed for posterior CAD/CAM crown restorations corroded with acidulated phosphate fluoride application.

This study assessed the gloss and surface roughness of computer-aided design/computer-aided manufacturing (CAD/CAM) resin composites corroded with acidulated phosphate fluoride (APF) application. One ceramic block, ten CAD/CAM resin composites for premolars, and four CAD/CAM resin composites for molars were assessed. The surface topography of the materials before and after APF application was observed using an electron microscope. The results were analyzed by Wilcoxon signed-rank test and Dunnett's many to one test (p<0.05). Gloss after APF application was significantly lower for all CAD/CAM resin composites except Artesano. Ra after APF application was significantly higher for all CAD/CAM resin composites except Artesano, Dentcraft HR Block, and Estelite P Block, and Sa was significantly higher for all CAD/CAM resin composites. Irregular surface topography was observed after APF application and the surface features differed among the materials. Therefore, APF application may be detrimental to the surface properties of CAD/CAM resin composites.

Effect of Er:YAG Laser Irradiation and Acidulated Phosphate Fluoride Therapy on Re-Mineralization of White Spot Lesions.

Statement of the Problem: Studies on the efficacy of erbium laser for enhancement of enamel resistance to acid attacks and its effects on fluoride uptake by the enamel are limited.Purpose: This study sought to assess and compare the effects of erbium-doped yttrium aluminum garnet (Er:YAG) laser irradiation and application of acidulated phosphate fluoride (APF) gel (alone and in combination) on remineralization of artificial white spot lesions (WSLs).Materials and Method: This in vitro, experimental study evaluated 90 buccal and lingual slabs of extracted human premolars. The specimens underwent pH cycling to induce WSLs. They were then randomly divided into 6 groups of caries-free positive control (c+), negative control with WSLs (ws), 1.23% APF gel applied on the enamel (F), Er:YAG laser irradiation (80 mJ, 10 Hz, and 8 J/cm2) of enamel (L), APF gel application followed by laser irradiation (FL), and laser irradiation followed by fluoride gel application (LF). The fluoride ion content of specimens was measured before and after the intervention using a potentiometer. Data were analyzed by ANOVA (p< 0.05).Results: APF gel application before/after laser irradiation maximally increased the fluoride uptake by the enamel (p= 0.000). Application of APF gel in group F and laser irradiation in group L increased fluoride uptake by the enamel, compared with groups 1 and 2 (p= 0.000). Laser- treated (L) and APF-treated (F) groups had no significant difference in this respect (p= 0.945). Maximum fluoride concentration was noted in combined laser and fluoride groups (FL=332.07ppm and LF=341.27ppm) with no significant difference between the two (p= 1.000).Conclusion: Er:YAG laser irradiation changes the chemical composition of enamel and probably promote its remineralization, especially when combined with APF gel application, which highlights its cariostatic potential.

The effects of combining erbium, chromium: Yttrium-scandium-gallium-garnet laser irradiation with fluoride application in controlling the progression of enamel erosion

ObjectiveIncreasing enamel resistance to acid may be useful for preventing cavitation and could reduce changes in the enamel’s microhardness. Topical fluoride application and laser irradiation promote acid resistance of dental substrates. The aim of the study was to assess the efficacy of erbium, chromium: yttrium-scandium-gallium-garnet laser irradiation in combination with fluoride application to control enamel erosion. DesignSixty human premolar specimens were prepared (N = 60) and were randomly assigned to 5 groups, twelve specimens in each group (n = 12/group) according to surface treatment. The groups were as follows: group 1 (C): control with no treatment; group 2 (F): application of 1.23% acidulated phosphate fluoride gel alone; group 3 (L): laser irradiation alone; group 4 (F+L): acidulated phosphate fluoride gel followed by laser irradiation; group 5 (L+F): laser irradiation followed by acidulated phosphate fluoride gel. All the specimens were eroded 10 min in citric acid. Baseline measurements were performed using a Vickers microhardness tester before surface treatment. Subsequently, all specimens were subjected to a 60 min erosion-remineralization cycle for five days followed by measurements of the final surface microhardness. Statistical comparisons were performed by a one-way analysis of variance and Tukey’s post hoc analysis. ResultsThe control, laser, and fluoride + laser groups showed a statistically significant decrease in microhardness values between baseline and post-erosion measurements (P < 0.05), indicating that these treatments could not prevent erosion progression. However, the fluoride and laser + fluoride groups showed a significant increase in microhardness values compared to baseline. ConclusionsOur results suggest that compared to that of the control group, acidulated phosphate fluoride application as well as laser irradiation prior to fluoride application increased enamel surface microhardness and prevented the progression of enamel erosion.

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.

Variation on Molecular Structure, Crystallinity, and Optical Properties of Dentin Due to Nd:YAG Laser and Fluoride Aimed at Tooth Erosion Prevention.

This in vitro study evaluated the compositional, crystalline, and morphological effects promoted by Nd:YAG laser on root dentin, and verified the effects of laser and topical acidulated phosphate fluoride application (APF-gel) on dentin erosion. 180 bovine dentin slabs were randomized into 4 groups (n = 45): G1–untreated, G2–APF-gel (1.23% F−, 4 min), G3–Nd:YAG (1064 nm, 84.9 J/cm2, 10 Hz), and G4–APF-gel application followed by Nd:YAG laser irradiation. The compositional, crystalline, and morphological effects promoted by treatments were investigated on five samples of each experimental group. The other samples were submitted to a 5-day, 10-day, or 15-day erosive and abrasive demineralization and remineralization cycling in order to create erosion lesions. The area and depth of lesions, as well as the optical attenuation coefficient, were assessed, and all data were statistically analysed (p < 0.05). Nd:YAG laser promoted the reduction of carbonate, the formation of tetracalcium phosphate, as well as the melting and recrystallization of the dentin surface. Laser significantly decreased the area and depth of erosion lesions and altered the optical attenuation coefficient when compared to untreated and APF-gel groups, but the association of APF-gel and laser did not promote an additional effect. Nd:YAG laser irradiation can be a promissory treatment to prevent dentin erosion and the abrasion process.

COMPARISON OF COLOR CHANGE IN GLASS IONOMER CEMENT (GIC) AFTER TOPICAL FLUORIDE APPLICATION Using Type II Conventional GIC and Topical Fluoride in Sodium Fluoride (NaF) and Acidulated Phosphate Fluoride (APF) Preparations

ABSTRACK Background : Conventional glass ionomer cement is an applicative material used in dentistry. Topical flouride is widely used as a preventive measure against caries; it is available in various forms, such as Sodium Flouride (NaF), Stannous Flouride (SnF2), and Acidulated Phosphate Flouride (APF). There are a few considerations in selecting which form to use, and one of them is the physical characteristic which may interact and change the color of previously placed conventional glass ionomer cement. Purpose : This study aimed to find out whether there was a difference of color change in conventional glass ionomer cement after topical fluoride application between NaF and APF form. Method : This study was a true experimental research using pre and posttest with control group design. There were 18 samples divided into 2 treatment groups and 1 control group. Each group had 6 samples. The measurement was carried out using optical spectrometer (OPT 101 type of photo detector) and microvolt digital. Result: The mean color change in conventional glass ionomer cement after APF and NaF topical application was 1,7300 mv and 0,4983 mv respectively. One way ANOVA test and post hoc LSD test results showed a significant difference (p<0.05). Conclusion : Discoloration on APF topical application was higher than NaF. Keywords : Acidulated Phosphate Fluoride (APF), discoloration of conventional glass ionomer cement, Sodium Fluoride (NaF), topical fluoride.

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.

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.

Dental management of severe early childhood caries

Background: Early childhood caries (ECC) is the new term given to dental decay in infants and toddlers. Severe ECC (S-ECC) is the most devastating caries, which is typical and follows a definite pattern. It is diagnosed by its clinical appearance and history of the child’s nursing/dietary habits. This article focuses on complete oral rehabilitation of two S-ECC patients. Case Presentation: Case 1: A 4 year-old boy accompanied by his mother reported to our department with the chief complaint of pain in the lower left back tooth region. A diagnosis of S-ECC was made based on history, examination and radiographic findings. Preventive regimens were enforced starting with parent counseling regarding oral hygiene. Case 2: A 6-year-old girl reported to our department with the chief complaint of masticatory difficulty and food lodgment in the upper right and left back tooth region. With detailed history and examination, a diagnosis of S-ECC was made. Again management was started by enforcing preventive treatment protocols with diet counseling, oral hygiene and brushing instructions, use of fluoridated tooth paste and professional acidulated phosphate fluoride application. Conclusion: Successful dental treatment for S-ECC can be rendered if the parents and the child are motivated and counselled. Treatment should be aimed at modifying all the four factors in caries tetralogy. Because of its aggressive nature, treatment should be specific for each individual patient.

FT-Raman spectroscopic analysis of Nd:YAG and Er,Cr:YSGG laser irradiated enamel for preventive purposes

This study evaluated the effect of combining laser irradiation with fluoride on an enamel microstructure and demineralization by FT-Raman spectroscopy (FTRS). Eighty human enamel slabs were divided into eight groups: (G1) untreated; (G2) acidulated phosphate fluoride application (APF—1.23% F− for 4 min); (G3) Nd:YAG irradiation (84.9 J cm−2, 60 mJ/pulse); (G4) Nd:YAG + APF; (G5) APF + Nd:YAG; (G6) Er,Cr:YSGG irradiation (2.8 J cm−2, 12.5 mJ/pulse); (G7) Er,Cr:YSGG + APF; and (G8) APF + Er,Cr:YSGG. After treatment, the samples were submitted to a ten-day pH-cycling model. Chemical changes were determined on the slabs before and after treatment, and also after pH-cycling, by FTRS in the range 400−4000 cm−1. The inorganic bands at 440, 590, 870, 960, 1100 cm−1, and the organic bands at 1270, 1450, 1670, 2945 cm−1 were considered. Demineralization promoted reduction in organic contents; Nd:YAG laser irradiation promoted loss of carbonate and organic content, while Er,Cr:YSGG did not produce significant changes in the relative band intensities of organic and inorganic contents of the enamel. In lased samples, no effects caused by pH-cycling on enamel were observed. In conclusion, laser treatment and its association with fluoride can somehow interfere with the demineralization dynamics, reducing its effects over the enamel.

Surface and mineral changes of enamel with different remineralizing agents in conjunction with carbon-dioxide laser.

Aim:The aim of this study was to evaluate the surface/mineral changes on enamel before and after the application of acidulated phosphate fluoride (APF) gel, fluoride enhanced hydroxyapatite gel and propolis in conjunction with carbon-dioxide (CO2) laser.Materials and Methods:Crowns of 40 human maxillary central incisors were collected and were divided into four groups of 10 each: Topical fluoride application only, topical fluoride application followed by CO2 laser irradiation, CO2 laser irradiation followed by topical fluoride application and CO2 laser irradiation before and after topical fluoride application. The 10 crowns in each group was again sectioned into four equal parts of mesio-incisal, disto-incisal, mesio-cervical and disto-cervical sections rendering 40 samples in each group. Each group was again subdivided into four subgroups: Subgroup C - untreated enamel surface (control). Subgroup A - APF gel application, subgroup R - fluoride enhanced hydroxyapatite gel application and subgroup P - propolis application. The surface morphology of the test samples were analyzed by scanning electron microscopy and mineral changes by energy dispersion X-ray spectrophotometer.Results:Total mineral content is maximum in Group 4A (CO2 laser irradiation before and after APF gel application) and calcium/phosphate ratio is highest in Group 4R (CO2 laser irradiation before and after Remin-Pro application). Group 2A (APF gel application followed by CO2 laser irradiation) has the maximum fluoride retention.Conclusion:Laser irradiation of enamel through a topically applied APF gel is effective in the prophylaxis and management of dental caries.

Effects of Er:YAG Laser Irradiation and Topical Fluoride Application on Inhibition of Enamel Demineralization

ABSTRACT Objective: The aim of this study was to evaluate the effect of the Er:YAG laser and acidulated phosphate fluoride application on enamel solubility around orthodontic brackets via atomic absorption spectrometry. Materials and Methods: Twenty freshly extracted upper premolar teeth were divided into 2 halves. Each half was covered with a nail varnish, excluding 1 mm (width) of space around each side of the bracket base. Orthodontic brackets were bonded in the center of the isolated area. Four groups were generated. The first group was the control group, and no treatment was performed. In group II (F), only fluoride was applied. Groups III and IV were laser and fluoride combination groups. In Group III (LF), fluoride was applied to the laser-irradiated surface, whereas laser irradiation was performed on the fluoridated enamel surface in Group IV (FL group). Afterwards, samples were demineralized in an acidic solution for 96 hours, and calcium assessment was performed using atomic absorption spectrome...

Acidulated Phosphate Fluoride Application Changes the Protein Composition of Human Acquired Enamel Pellicle

We evaluated, by proteomic analysis, whether the chemical changes provoked on enamel by acidulated phosphate fluoride (APF) application alter the protein composition of acquired enamel pellicle. Enamel slabs, pretreated with distilled water (negative control), phosphoric acid (active control) or APF solution, were immersed in human saliva for pellicle formation. The adsorbed proteins were extracted and analyzed by liquid chromatography-mass spectrometry/mass spectrometry. Fifty-six proteins were identified, 12 exclusive to APF and 11 to phosphoric acid. APF decreased the concentration of histatin-1, but increased the concentration of S100-A9, which is confirmed by immunoblotting. The findings suggest that APF application changes the acquired enamel pellicle composition.

The effects of treated time of acidulated phosphate fluoride solutions on enamel erosion

The aim of this study was to reevaluate the treatment time of topical application of acidulated phosphate fluoride (APF) solution. Bovine intact enamel was treated with APF solution (pH 3.5, 9,000 ppm F) for 0, 1, 2, 3, 5, and 10 min. Fluoride penetration into the enamel was determined using electron probe micro analyser (EPMA), and the hardness of APF-treated demineralized enamel was evaluated via the micro Vickers technique. Micro Vickers hardness (HV) was significantly different in enamel treated with APF for 1 min and that treated for >2 min, and also between enamel treated for 2 and that treated for 3 min in samples demineralized for 2 h. No significant difference in the surface roughness (Ra) by confocal laser scanning microscopy was evident at the 3 and 5 min time points. The results of the EPMA analysis, HV, and Ra tests suggest a clinically beneficial effect of APF when applied for 3 min.

Effects of acidulated phosphate fluoride gel application on surface roughness, gloss and colour of different type resin composites

Objective Application of acidulated phosphate fluoride (APF) gel has been reported to cause deterioration of resin composites. This study investigated the effects of APF gel application on surface roughness, gloss and colour of resin composites. Methods A2-shade resin disks of 2 mm thickness polished with 180-grit and 3000-grit SiC papers were made with Estelite Σ Quick (EQ), Clearfil Majesty (CM) and Beautifil II (B2). Six disks were prepared for each group. APF gel was applied in a 3 mm thickness on the top surface of resin disks and left for 30 min followed by rinsing and ultrasonic washing. This procedure was repeated 4 times. The L* a* b* values, colour difference (Δ E* ab), opacity, surface gloss and roughness of specimens before and after APF application were compared. Data were analysed ANOVA and Fisher's PLSD test with α = 0.05. Results For the 3000-grit polishing groups, the order of influence of APF gel application on colour of resin composites was CM > B2 > EQ. Both in the 180- and 3000-grit polishing groups, colour difference before and after APF gel application was hard to detect (CM and B2) or impossible to detect (EQ) by naked eye. On the other hand, for all the resin composites, the gloss was significantly decreased by APF gel application. APF gel appeared to cause deterioration and dissolution of resin composites used in this study. Significance In this limited study, supra-nano spherical filled Estelite Σ Quick showed the least change on colour, gloss and surface roughness by APF gel application.

The roughness, microhardness, and surface analysis of nanocomposites after application of topical fluoride gels

Objectives Application of acidulated phosphate fluoride (APF) gels has long been considered to cause deterioration of composite surfaces. The aims of this study were to demonstrate that nanocomposite surfaces were not affected by some APF gels and to investigate the possible underlying mechanisms. Methods The elemental composition and viscosity of 3 acidulated phosphate fluoride (APF) agents (60 Second Taste Gel, Topex, and Zap) and 1 neutral fluoride agent (pH7 Gel) were analyzed. Subsequently, 320 specimens of 3 nanocomposites (Premisa, Filtek Z350, and Grandio) and a microhybrid composite (Estelite Sigma) with 80 specimens for each composite were randomly divided into 5 groups ( n = 16) and treated with 4 fluoride gels as well as distilled water which served as the control. Fluoride gels were applied on composite resin surfaces 4 times, 30 min each time. The roughness and microhardness were measured after treatments. Qualitative examination of the surface degradation of the composites was carried out with Fourier transforming infrared spectroscopy (FTIR) and scanning electron microscopy (SEM). Results Topex and Zap did not cause surface changes of composite resins, the possible reason being ascribed to the presence of magnesium aluminum silicate (MAS) clays. In contrast, 60 Second Taste Gel treatments caused significant roughness increase, microhardness decrease, more prominent filler dissolution, and IR spectral changes of Premisa, Filtek Z350, and Grandio. Estelite Sigma was less affected by the 4 fluoride gels. Significance The composite surfaces were not affected by Topex or Zap even after extended treatments. These two APF gels may be more suitable for clinical applications.

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.