Topical Fluoride Treatment Research Articles

Dentinal hypersensitivity following scaling and root planing: comparison of low-level laser and topical fluoride treatment

The aim of this study is to compare the effectiveness of low-level laser irradiation to traditional topical fluoride treatment for treatment choices of dentinal hypersensitivity following scaling and root planing. The experimental group (15 patients) was treated with low-energy-level diode laser at each site of dentinal hypersensitivity following scaling and root planning. The control group (15 patients) received topical fluoride treatment (protective varnish for desensitization). All the patients were treated at baseline visit, and then at day 2 and 4 after the initial treatment; the pain was subjectively assessed by the patients as strong, medium, medium low, low, or no pain. Total absence of the dental hypersensitivity was reported in 26.66% of the examined group even after the second visit, compared to the control group where complete resolution of the hypersensitivity was not present after the second visit in any of the treated cases. Complete absence of pain was achieved in 86.6% of patients treated with laser and only in 26.6% in the fluoride treated group, after the third visit. Based on our findings, we conclude that low-energy biostimulative laser treatment can be successfully used for treatment of dental hypersensitivity following scaling and root planing.

Dental enamel irradiated with infrared diode laser and photoabsorbing cream: Part 1 -- FT-Raman Study.

The aim of this FT-Raman study was to investigate laser-induced compositional changes in enamel after therapy with a low-level infrared diode laser and a photoabsorbing cream, in order to intensify the superficial light absorption before and after cariogenic challenge. Dental caries remains the most prevalent disease during childhood and adolescence. Preventive modalities include the use of fluoride, reduction of dietary cariogenic refined carbohydrates, plaque removal and oral hygiene techniques, and antimicrobial prescriptions. A relatively simple and noninvasive caries preventive regimen is treating tooth enamel with laser irradiation, either alone or in combination with topical fluoride treatment, resulting in reduced enamel solubility and dissolution rates. Due to their high cost, high-powered lasers are still not widely employed in private practice in developing countries. Thus, low-power red and near-infrared lasers appear to be an appealing alternative. Twenty-four extracted or exfoliated caries-free deciduous molars were divided into six groups: control group (no treatment; n = 8); infrared laser treatment (L; n = 8) (810 nm at 100 mW/cm(2) for 90 sec); infrared diode laser irradiation (810 nm at 100 mW/cm(2) for 90 sec) and photoabsorbing cream (IVL; n = 8); photoabsorbing cream alone (IV; n = 8); infrared diode laser irradiation (810 nm at 100 mW/cm(2) for 90 sec) and fluorinated photoabsorbing agent (IVLF; n = 8); and fluorinated photoabsorbing agent alone (IVF; n = 8). Samples were analyzed using FT-Raman spectroscopy before and after pH cycling cariogenic challenge. There was a significant laser-induced reduction and possible modification of the organic matrix content in enamel treated with the low-level diode laser (the L, IVL, and IVFL groups). The FT-Raman technique may be suitable for detecting compositional and structural changes occurring in mineral phases and organic phases of lased enamel under cariogenic challenge.

A case study of multiple-treatments meta-analysis demonstrates that covariates should be considered

Objective To illustrate the potential and challenges of the simultaneous analysis of a network of trials, using as a case study the investigation of the relative effectiveness of four topical fluoride treatments and two control interventions (placebo and no treatment) in preventing dental caries in children. Study Design and Setting We performed multiple-treatments meta-analysis within a Bayesian framework by synthesizing six Cochrane reviews. We explored the compatibility between direct and indirect evidence and adjusted the results using a meta-regression model to take into account differences in the year of randomization across studies. Results The validity of our conclusions for the superiority of fluoride toothpaste as indicated from the initial network analysis using Bayesian methods was challenged when we adjusted for possible confounders. The network was dominated by studies comparing placebo with toothpaste, which were older and had been carried out in populations with higher baseline risk than studies involving other fluoride modalities. Conclusion After adjusting for possible differences across studies, we did not find clear evidence that any topical fluoride modality is more effective than any other. Multiple-treatments meta-analysis methods allow for more detailed investigations than naïve methods in the analysis of indirect evidence on treatment effects.

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.

The Use of Fluoride Varnish in Children: A Critical Review with Treatment Recommendations

This paper expands upon the recent report of the expert panel commissioned by the American Dental Association's Council on Scientific Affairs by offering evidence-based clinical recommendations for professionally applied topical fluoride. The authors strongly support the panel's recommendation that clinicians should rely upon caries risk criteria for determining those children who will receive a topical fluoride treatment. In this paper, the authors will take a position that when clinicians have made a decision to use topical fluoride therapy, fluoride varnish should be the only consideration for children ages 0-6 and children of all ages who have special health care needs that limit their attention span and/or cooperation. The authors offer an accompanying rationale based on dosage reduction and efficacy, that fluoride varnish should be the topical fluoride of choice for children ages 6-12. The authors expand upon the recent panel recommendations by examining published clinical trials to determine the best clinical techniques for varnish use. The authors offer clinicians the following recommendations prior to varnish use: a pre-application rubber cup or tooth brush prophylaxis, the application of varnish to dry teeth and post-operative instructions to include both no tooth brushing and a soft diet for 12 hours.

Non‐destructive assessment of inhibition of demineralization in dental enamel irradiated by a λ = 9.3‐µm CO2 laser at ablative irradiation intensities with PS‐OCT

Polarization sensitive optical coherence tomography (PS-OCT) has great promise for the non-destructive assessment of the efficacy of anti-caries agents such as fluoride and thermal laser treatments on enamel surfaces. The purpose of this study was to demonstrate that PS-OCT can be used to measure demineralization in craters/incisions prepared in enamel by a CO(2) laser operating at the high irradiation intensities required for cavity preparations. Incisions in bovine enamel surfaces were produced by a CO(2) laser used with a water spray. The laser was operated at lambda=9.3 microm with a pulse duration of 15 micros and an incident fluence of 20 J/cm(2). The laser treatments were also combined with topical fluoride treatments. A PS-OCT system operating at 1,310 nm was used to acquire polarization resolved images of six areas including sound and laser-ablated+topical fluoride treated zones on each sample. After imaging the teeth, they were sectioned and the thin sections were examined with polarized light microscopy (PLM) and transverse microradiography (TMR). The integrated reflectivity and lesion depth derived from the PS-OCT scans, the integrated mineral loss and depth measured using TMR and the lesion depth measured with PLM were acquired for each area on the fifteen samples for comparison. The integrated reflectivity and depth in the areas treated by the laser and fluoride were significantly lower (P<0.05) than for the untreated enamel. Similar results were observed for TMR and PLM. These results suggest that PS-OCT has great potential for the non-destructive "in vivo" assessment of the inhibition of demineralization by lasers at ablative irradiation intensities with and without topical fluoride application.

Nano-mechanical Properties of Fluoride-treated Enamel Surfaces

Calcium-fluoride-like deposits play a key role in caries prevention by topical fluoride. Previous microhardness analyses have introduced errors due to a substrate effect, and thereby could not substantiate the early loss of these deposits. To address this question, we applied Atomic Force Microscopy (AFM) and a nano-indentation technique in this study to characterize the nano-mechanical properties and topographic structure of enamel surfaces following topical fluoride treatment. The deposits were found to have a low nano-hardness and a high nano-wear depth, which explains the early loss of calcium-fluoride-like deposits. However, a 22% increase in the fluoride concentration could still be detected on the treated enamel surface following the removal of the surface deposits, justifying the long-term effectiveness of topical fluoride treatment.

Kinetics of fluoride release from and reuptake by orthodontic cements

The purposes of this in-vitro study were to compare the fluoride-release profiles and the fluoride release, reuptake, and rerelease characteristics of orthodontic cements before and after topical fluoride treatment. The orthodontic cements tested were 2 resin-modified glass ionomers (Vitremer [3M Dental Products, St Paul, Minn] and Fuji Ortho LC [GC Dental, Tokyo, Japan]), a glass ionomer (Ketac-Cem [Espe-Premier Dental Products, Norristown, Pa]), and a composite (Concise [3M Dental Products]). Fifteen specimens of each material were stored in plastic vials containing deionized water at 37 degrees C. Fluoride release was measured daily for the first 15 days and then weekly for a 57-day period. After initial elusion, specimens were exposed to 1.23% acidulated phosphate fluoride gel, and the fluoride release was monitored daily for 7 consecutive days. The fluoridation/elution procedure was repeated once, and the specimen surfaces were then examined with a scannning electron microscope. Kinetic release profiles of the test materials were deduced. All materials except Concise had similar fluoride-release profiles. Vitremer demonstrated the highest fluoride release, followed by Fuji Ortho LC and then Ketac-Cem in the time period of the study (P <.01). All glass-ionomer cements, but especially Fuji Ortho LC, showed enhanced uptake and release on repeated exposure to the topical fluoride treatment. Nevertheless, Vitremer showed the greatest surface degradation after refluoridation. All resin-modified and conventional glass ionomers studied exhibited the capacity for fluoride release and reuptake after fluoridation, but the subsequent fluoride release was transitory. Thus, the benefit from fluoride reuptake in these orthodontic cements should be balanced with the risk of weakening them after repeated fluoridation.

Solubility of calcium fluoride and fluorapatite by solid titration

Objectives The solubility isotherms, S, of two compounds detected after topical fluoride treatment – calcium fluoride (CaF 2) and fluorapatite (FAp) – are of fundamental interest in saliva chemistry and in the context of reduction of acid dissolution of teeth, whether through the process of caries or from exogenously ingested acids. Solid titration has shown its reliability and reproducibility for complicated systems that are not suitable for study by the traditional excess-solid method. The primary aim of this work was to ascertain S[CaF 2] and S[FAp]. Methods Solid titration was used for CaF 2 (pH 2.3–9.5) and FAp (pH 2.8–5.1) in 100 mM KCl solution at 37.0 ± 0.1 °C, and further to determine the apparent solubility of hydroxyapatite (HAp) in the presence of 1 mM fluoride (pH 3.2–4.8). Results Peculiar results were obtained at first which were attributed to the adsorption or reaction of fluoride with the reaction vessel glass surface interfering with the intended solution equilibria. Wax-lined glass apparatus resolved this problem. The solubility isotherm of CaF 2 was then as theoretically expected at pH < 8, but above this point a new solid species (CaFOH) was postulated to account for the data. The position of FAp was as expected relative to HAp, being about 0.63× less soluble. FAp was the only detectable equilibrium solid at pH 3.2, 3.6 and 4.1. The apparent solubility of HAp was depressed somewhat by the presence of 1 mM fluoride. Conclusion The solid titration method was again found to be reliable once glass interferences were eliminated. The interaction of fluoride with borosilicate glass may have affected other work in the field; such work may therefore require re-evaluation. The S[FAp] is very similar to that of HAp determined by solid titration. Excess-solid method results are strongly discrepant from the present determination and may not be reliable, primarily due to lack of solution speciation data for that calculation.

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.

Efficacy of Waiting Periods and Topical Fluoride Treatment on Toothbrush Abrasion of Eroded Enamel in situ

The aim of this study was to investigate the effectiveness of both waiting periods between acid exposure and tooth brushing and fluoride applications in preventing toothbrush abrasion of acid-softened enamel surfaces. The study, on 5 subjects, had an in situ crossover design with experimental periods of 5 days each. Human enamel samples were recessed in mouth appliances and at the end of each experimental period, enamel loss was determined profilometrically. Specimens were eroded extraorally (2 × 20 min per day; 0.05 M citric acid), standardized brushing (2 × 30 s per sample per day; powered toothbrush) was performed in situ. The groups were: (1) erosion only, (2) brushing with fluoride-free toothpaste directly after, (3) 2 h after, or (4) before erosion; fluoride application was either (5) brushing with a fluoride toothpaste or (6) brushing with a fluoride toothpaste or gel, and rinsing with a fluoride mouth rinse. Enamel loss was (1) 45.2 ± 10.8, (2) 79.3 ± 7.8, (3) 81.7 ± 9.5, (4) 69.7 ± 13.8, (5) 51.5 ± 13.0, and (6) 41.2 ± 1.8 µm. Brushing without fluoride increased the enamel loss significantly (p ≤ 0.001), waiting for 2 h had no protective effect, and brushing before erosion decreased enamel loss values only by 12% (n.s.). In the fluoride groups, enamel loss was significantly lower than after brushing with the fluoride-free toothpaste and comparable to values after erosion only (n.s.). Waiting periods had only a minor effect, whilst the application of fluoride appeared promising.

Evaluation of fluoride release from teeth after topical application of NaF, SnF2 and APF and antimicrobial activity on mutans streptococci

The objectives of this study were to evaluate and compare the amount and pattern of fluoride release from teeth after topical application of 2% NaF, 8% SnF2 and 1.23% APF at different time intervals. The growth inhibitory effects of this released fluoride ion was assessed on mutans streptococci (MS) and correlated with the fluoride release. Forty premolars divided into four groups were subjected to different topical fluoride treatments. All the teeth were immersed individually in deionized water and were transferred to containers at 1 hour, 1 day and 1 week time intervals. 240 samples in total were used for fluoride estimation by ion selective electrode method and the samples from the other subgroup were used for evaluation of antimicrobial activity on mutans streptococci (MS) by bacterial inhibition assay method. The results showed that the highest fluoride release (7.83 +/- 0.55 ppm) was seen in SnF2 treated specimens, as compared to that of NaF (3.71 +/- 0.60ppm) and APF (3.30 +/- 0.51ppm), the difference being statistically significant (P<0.01). This was observed immediately after 1 hour, followed by a drastic reduction thereafter. No zones of inhibition were observed at the released fluoride concentrations at different time intervals in the different groups. 8% SnF2 is expected to have greater anticaries property from the high fluoride releasing property for prolonged period of time.

Early childhood caries (ECC): a preventive-conservative treatment mode during a 12-month period.

To evaluate a preventive treatment mode for early childhood caries (ECC). The population to be studied included 30 children who, over a 12-month period, presented with ECC to a private dental clinic. Parents preferred non-invasive, preventive treatment over restorations. Parents were given hygiene and proper feeding instructions. Mesial slicing was performed where proximal caries was observed. Children were examined once every two months. They received supervised professional topical fluoride treatment. Plaque level, brushing, stopping the bottle, eating sweets, appearance of new lesions or exacerbation of existing condition were observed and recorded. In the vast majority of patients, the progression of ECC was arrested after the preventive regimen. Three children required restorations. They had failed to limit sugar consumption and to comply with brushing instruction. General improvement was observed in plaque control, brushing habits and sweets consumption. Preventive measures may successfully arrest ECC and thereby avoid invasive procedures as well as the need of anesthesia.

Flexural Strength and Modulus Properties of Carbamide Peroxide?Treated Bovine Dentin

The effects of carbamide peroxide bleach on tooth structure are uncertain. The purpose of this study was to investigate the effects of direct or indirect carbamide peroxide application on dentin flexural strength and modulus in vitro. Dentin bars were machined from bovine incisors and treated with 10% carbamide peroxide for 6 h/d for 14 days. Four groups were created, with eight bars in each group: group 1-direct bleach application only; group 2-indirect bleach application only; group 3-direct bleach application followed by a 2-week storage in artificial saliva; group 4-direct bleach application followed by a 2-week storage in artificial saliva and daily topical fluoride treatments. The specimens' flexural strength and modulus were tested after 24 hours, and the results were compared with water controls using independent t-tests (p < .05). Flexural strength results (in megapascals) for bleached versus control dentin (1=205+/-26 vs 215+/-14, 2=257+/-25 vs 261+/-14, 3=180+/-22 vs 193+/-36, 4=157+/-18 vs 184+/-11) were significantly lower in group 4 (p=.005). Modulus results (in gigapascals) for bleached versus control dentin (1=10.7+/-1.4 vs 12.2+/-0.6, 2=14.2+/-1.7 vs 14.4+/-1.6, 3=10.0+/-2.0 vs 10.9+/-1.3, 4=9.0+/-1.2 vs 11.1+/-1.0) were significantly lower in groups 1 and 4 (p=.013 and p=.003, respectively). There were no significant differences in strength and modulus results between the bleached and control dentin in groups 2 and 3. A direct application of carbamide peroxide to bovine dentin significantly decreased some dentin mechanical properties in vitro. An indirect application of carbamide peroxide to dentin did not significantly decrease dentin strength and stiffness. This in vitro study suggests that a bleaching treatment, when applied to the enamel of intact teeth, does not significantly affect the mechanical properties of the underlying dentin. However, when applied directly to dentin in clinical situations such as root exposure or occlusal attrition, the bleaching treatment may result in altered mechanical properties of dentin. The clinical consequences of this observation are, however, unknown.

Evaluation of fissure sealant applied to topical fluoride treated teeth

Fissure sealant is an important tool in the prevention of dental caries. This study evaluated the effect of treating the enamel with topical fluoride gel prior to acid etching on sealant retention clinically (Part I) and in vitro (Part II). In part I a split mouth design using contralateral first permanent molars was conducted. Seventy (35 pairs) molars were sealed. Fissure sealant was applied on one side of the mouth (control group) and the contralateral tooth received acidulated phosphate fluoride gel (test group) prior to acid etching. The sealant was evaluated after 6 and 12 months and scored as intact, partially lost or completely missing. In part II, the shear bond strength between sealant and buccal enamel of extracted permanent molars without or with topical fluoride treatment was evaluated. Results showed no statistically significant differences between the test and control groups either clinically or in vitro. It is concluded that topical fluoride application prior to acid etching does not have a deleterious effect on sealant retention. However, further investigations should be conducted using different types of fluoride before altering the traditional practices.

Laser-assisted inhibition of artificial caries-like lesion formation in enamel of deciduous teeth

The purpose of this in vitro study was to assess the caries-preventive potential of a 809-nm diode laser on the enamel of deciduous teeth compared to topical fluoride application. The enamel surface of 80 samples was polished in an area of 2×2 mm. These tooth specimens were randomly assigned to a control and three test groups: (1) no treatment/control; (2) application of a 0.1-mg fluoride varnish for 6 h; (3) diode laser application (809 nm); (4) combined application—laser/fluoride varnish. Caries-like lesions were created by pH cycling. In the control group, all samples showed lesions up to 30 μm in depth. After laser application in 15 of 20 samples, lesions could be identified. Topical fluoride treatment in group 2 (varnish) and group 4 (laser/varnish) inhibited the development of caries-like lesions completely in all samples. In this in vitro investigation, topical fluoride treatment enhances the resistance of sound enamel of deciduous teeth more effectively than diode laser application.

Stainless steel brackets failure rate after topical fluoride application in etching procedures

Enamel demineralization that occurs adjacent to directly bonded orthodontic attachments is of great concern to orthodontists. One of the suggested procedures to overcome this problem is to use topical fluoride treatment after acid etching. The purpose of this study was to evaluate the failure rate of stainless steel bracket with metal mash base after topical application of(1.1%) neutral sodium fluoride gel after(37%) phosphoric acid etching. Twenty patients with full maxillary and mandibular "0.018" standard edgewise fixed appliances were included. Maxillary right, mandibular left sides were received the topical sodium fluoride gel application after etching with(37%) H3PO4 for(30) seconds. The gel was applied for(4) minutes after etching, then rinse with air and water stream for(5) seconds; while in the contralateral sides the bonding was done conventionally. The bonding adhesive was the No-Mix chemical cure adhesive. The follow-up period was(12-15) months. The results showed that brackets failure rate in fluoridated group did not differ significantly from the non-fluoridated one. Hence the(1.1%) neutral sodium fluoride may have a clinical application in preventing demineralization that occurred around and under orthodontic brackets without any significant increase in failure rate of stainless steel brackets

Topical Fluorides in Caries Prevention and Management: A North American Perspective

A review of evidence-based literature indicates incomplete evidence for the efficacy of most measures currently used for caries prevention, with the exception of fluoride varnishes and the use of fluoride-based interventions for patients with hyposalivation. Not all fluoride agents and treatments are equal. Different fluoride compounds, different vehicles, and vastly different concentrations have been used with different frequencies and durations of application. These variables can influence the clinical outcome with respect to caries prevention and management. The efficacy of topical fluoride in caries prevention depends on a) the concentration of fluoride used, b) the frequency and duration of application, and to a certain extent, c) the specific fluoride compound used. The more concentrated the fluoride and the greater the frequency of application, the greater the caries reduction. Factors besides efficacy, such as practicality, cost, and compliance, influence the clinician's choice of preventive therapy. For noncavitated smooth surface carious lesions in a moderate caries-risk patient, the appropriate fluoride regimen would be semiannual professional topical application of a fluoride varnish containing 5 percent NaF (22,600 ppm of fluoride). In addition, the patient should use twice or thrice daily for at least one minute a fluoridated dentifrice containing NaF, MFP, or SnF2 (1,000-1,500 ppm of fluoride), and once daily for one minute a fluoride mouthrinse containing .05 percent NaF (230 ppm of fluoride). If the noncavitated carious lesion involves a pit or fissure, the application of an occlusal sealant would be the most appropriate preventive therapy. The management of the high caries-risk patient requires the use of several preventive interventions and behavioral modification, besides the use of topical fluorides. For children over six years of age and adults, both office and self-applied topical fluoride treatments are recommended. For office fluoride therapy at the initial visit, a high-concentration agent, either a 1.23 percent F APF gel (12,300 ppm of fluoride) for four minutes in a tray or a 5 percent NaF varnish (22,600 ppm of fluoride), should be applied directly to the teeth four times per year. Self-applied fluoride therapy should consist of the daily five-minute application of 1.1 percent NaF or APF gel (5,000 ppm of fluoride) in a custom-fitted tray. For those who cannot tolerate a tray delivery owing to gagging or nausea, a daily 0.05 percent NaF rinse (230 ppm of fluoride) for 1 minute is a less effective alternative. In addition, the patient should use twice or thrice daily for at least 1 minute a fluoridated dentifrice as described above for treatment of noncavitated carious lesions. In order to avoid unintentional ingestion and the risk of fluorosis in children under six years of age, fluoride rinses and gels should not be used at home. Furthermore, when using a fluoride dentifrice, such children should apply only a pea-size portion on the brush, should be instructed not to eat or swallow the paste, and should expectorate thoroughly after brushing. Toothbrushing should be done under parental supervision. To avoid etching of porcelain crowns and facings, neutral NaF is indicated in preference to APF gels for those patients who have such restorations and are applying the gel daily. The rationale for these recommendations is discussed. Important deficiencies in our knowledge that require further research on topical fluoride therapy in populations with specific needs are identified.

The Influence of Saliva on the Formation of Calcium Fluoride–Like Material on Human Dental Enamel

After a topical fluoride application two resulting features can be observed and measured: the formation of calcium fluoride and a decrease in caries incidence. For the formation of solid calcium fluoride the source of calcium may be either the enamel itself or remaining saliva or – in plaque – plaque fluid and calculus. The aim of the present study was to examine whether saliva through its calcium content has any influence on the amount of calcium fluoride formed by a topical fluoride treatment of enamel. The roots and the fissure systems of 64 freshly extracted intact third molars were covered with nail varnish and allocated to eight groups of 8. Half of the groups were put in fresh paraffin–stimulated saliva for 5 min after which surplus of saliva was shaken off whilst the other groups remained in distilled water. The teeth were given a 2–min topical treatment with either distilled water (control), neutral 0.2% NaF, neutral 2% NaF or 2% NaF acidified with 0.1 mol/l H₃PO₄. After the topical treatment the teeth were rinsed in running tap water for 5 min, dried and revarnished before determination of calcium fluoride. It was found that the amount of calcium fluoride formed depended on the concentration of fluoride (the higher the fluoride concentration, the higher was the amount of calcium fluoride), the acidity of the solution (presumably due to the increase in available calcium through enamel dissolution) and the presence of saliva (presumably due to its calcium content and its mucinous nature). As there was always more calcium fluoride formed in the presence of saliva, thorough drying of the teeth prior to topical treatments may be superfluous

Fluoride release and re-uptake in direct tooth colored restorative materials

Objectives. Glass ionomers may be “recharged” through topical fluoride (F −) treatments; however, this reported “recharging,” may be attributed to surface changes after F − treatment. This study examined differences in F − release and re-uptake among dual-cured and chemically-cured glass ionomers, and a photo-cured F − releasing composite. A secondary goal was to determine if tensile strength or surface roughness changed due to F − release, or F − re-uptake and re-release. Methods. In Phase 1, initial surface roughness and diametral tensile strength were measured. F − release was measured for 30 days. Strength and roughness were then remeasured. In Phase 2, surface roughness was measured, then materials were treated with a 5000 ppm neutral F − gel, the same gel without F −, or phosphoric acid. F − release was measured for 30 days, then final surface roughness and strength were determined. Results. Significant differences were found in amount and rate of F − release, and F − re-uptake and re-release among study materials and enamel controls ( p<0.001). The amount and rate of F − re-release after NaF treatment differed significantly from F − release after acid treatment in glass ionomers, although both groups showed increased F − release after surface treatment ( p<0.001). There were no significant changes in tensile strength or surface roughness after F − release or F − re-uptake and re-release as determined by ANOVA. Significance. The results of this in vitro study indicate that applications of neutral 5000 ppm F − gel to aged glass ionomer restorations results in a significant fluoride uptake and subsequent release. The data suggest that the application of neutral fluoride gel to glass ionomer restorations in situ may result in increases in oral fluoride concentrations, without affecting the restoration's surface roughness or tensile strength.