Comparison of fluoride uptake into tooth enamel from two fluoride varnishes containing different calcium phosphate sources.

OBJECTIVE: The objective of this in vitro study was to compare two 5% sodium fluoride varnishes, each containing different sources of calcium and phosphate, for their ability to deliver fluoride into treated sound tooth enamel and adjacent, but untreated demineralized enamel. METHODS: Six sets of 12 bovine enamel cores were mounted in plexiglass rods and the exposed surfaces were polished. Synthetic lesions were formed in the surface of three sets by soaking in thickened, pH 5.0, 1M lactic acid, 50% saturated with calcium hydroxyapatite. A fluoride varnish containing tri-calcium phosphate (TCP) was applied to one set of sound enamel cores, and a second, delivering amorphous calcium phosphate (ACP), was applied to another. A third set of sound enamel cores was water-treated. Each treated sound core was paired with an untreated lesioned core, and the pairs were soaked in artificial saliva for 24 hours at 37 degrees C. The treated cores, but not their lesioned counterparts, were initially soaked in 1.0 N KOH saturated with calcium phosphate for 18 hours. Each core was separately etched with 1.0 N perchloric acid for exactly 15 seconds, and fluoride measured by an ion-sensitive electrode after neutralizing with NaOH and buffering in TISAB II. The amount of calcium extracted was also determined by atomic absorption spectrophotometry as a measure of etch depth. RESULTS: Fluoride uptake average was 1677 +/- 193 ppm, 455 + 38 ppm, and 44 +/- 5 ppm for the sound enamel cores treated with ACP varnish, TCP varnish, and water treatment, respectively. Fluoride uptake into the demineralized enamel averaged 5567 +/- 460 ppm, 2126 +/-126 ppm, and 49 -/+ 4 ppm for demineralized enamel paired with the sound cores treated with ACP varnish, TCP varnish, and water, respectively. The differences between the ACP varnish, the TCP varnish, and the water treatments were statistically significant (p < 0.05). CONCLUSION: The ACP varnish formulation delivers statistically significantly more fluoride to both intact and demineralized enamel than the formulation containing TCP.

Effectiveness of a baking soda toothpaste delivering calcium and phosphate in reducing dentinal hypersensitivity.

OBJECTIVE: The purpose of this controlled clinical trial was to determine the effectiveness and safety of a single-phase dentifrice that delivers calcium, phosphate, and fluoride to the tooth surface (Arm & Hammer Enamel Care for Sensitive Teeth toothpaste, United Kingdom) in reducing dentinal hypersensitivity. METHODS: Two-hundred and eight qualifying subjects were randomly assigned to either the Enamel Care dentifrice group or a control dentifrice group, and brushed twice daily with their assigned dentifrice for eight weeks. Pain/discomfort in response to a thermal stimulus was assessed at baseline, week 4, and week 8 using a Visual Analogue Scale (VAS; primary outcome variable) and the Schiff Thermal Sensitivity Scale (STSS; secondary outcome variable). After eight weeks, volunteers from the Enamel Care group were switched to the control dentifrice and participated in a second eight-week study to determine the degree of persistence of pain reduction. RESULTS: Both groups had statistically significant VAS score reductions from baseline at weeks 4 and 8, with mean VAS scores in the Enamel Care group decreasing by 45.6% at week 4 and 61.1% at week 8 (p < 0.0001). Enamel Care was statistically significantly more effective than the control at weeks 4 and 8, with respective mean VAS reductions of 63% (p < 0.0001) and 33% (p = 0.0004) greater than the control. Consistent with the VAS score results, the Enamel Care group had respective statistically significant STSS score reductions of 77% and 58% greater than the control group (p < 0.0001). The reductions in dentinal hypersensitivity seen in the Enamel Care group at week 8 persisted for an additional eight weeks, during which the subjects discontinued use of Enamel Care and brushed with the control dentifrice. CONCLUSION: Enamel Care for Sensitive Teeth toothpaste (United Kingdom) is an effective dentifrice for the management of dentinal hypersensitivity, and its efficacy persists for a least eight weeks following discontinued product use.

Reduction of Defoliation in Citrus Caused by Mycosphaerella citri with a Novel Biocompatible Fungicide.

A novel, biocompatible fungicide, CD-2346, was evaluated for management of defoliation associated with greasy spot (Mycosphaerella citri Whiteside) in orange (Citrus sinensis (L.) Osbeck) and grapefruit (Citrus × paradisi Macfad.). This product contains potassium bicarbonate, potassium carbonate, urea, and a surfactant. CD-2346 (7.0 kg/ha) and a half-rate combination of CD-2346 + benomyl (0.55 kg/ha) were compared with a higher rate of benomyl (1.1 kg/ha) and commercial standards of oil (petroleum distillate FC-435-66 [70 to 93.5 liters/ha]) or oil (46.8 liters/ha) + copper sulfate (2.2 to 2.8 kg/ha). Fungicide efficacy was assessed using the area under the defoliation progress curve (AUDPC) and final defoliation in entire trees or final greasy spot severity in individual leaves. All fungicide treatments reduced the AUDPC, and all but benomyl reduced either final defoliation percentage or disease severity in individual leaves. CD-2346 and the reduced-rate combination of CD-2346 + benomyl were generally equal or superior to the full rate of benomyl in decreasing the AUDPC; CD-2346 + benomyl was equivalent to oil in reducing the AUDPC. Oil and CD-2346 treatments similarly reduced final defoliation, but oil + copper sulfate was superior to CD-2346 in reducing the AUDPC and final greasy spot defoliation or severity.

Laboratory enamel solubility reduction and fluoride uptake from enamelon dentifrice.

The presence of calcium-releasing ingredients in toothpastes containing sodium fluoride is usually avoided to prevent loss of active fluoride due to the formation of the insoluble calcium salt. The purpose of this study was to determine the bio-availability of fluoride from Enamelon Toothpaste (E), which simultaneously supplies fluoride, calcium and phosphate salts from a dual dispensing package. Fluoride uptake into artificially lesioned enamel cores due to the use of the test dentifrice (E) diluted 1:3 in whole human saliva was compared to that from a clinically proven effective sodium fluoride/silica USP reference toothpaste (C) and a non-fluoride control (E-w/o F). Enamel solubility reduction due to the use of E, C and E-w/o F was measured by determining the quantity of phosphate released to lactic acid buffer before and after treatment of the crowns of molars with 1:3 slurries of the dentifrices in water. Fluoride uptakes and enamel solubility reductions were 5031 +/- 158 ppm and 21.6 +/- 2.2% for E, 1915 +/- 39 ppm and 13.6 +/- 2.0% for C, and -3 +/- 2 ppm and 0.8 +/- 1.7% for E-w/o F. The fluoride uptake and enamel solubility reductions from E were significantly greater than from C (p < 0.001, Fisher LSD), and both fluoride-containing dentifrices significantly outperformed E-w/o F (p < 0.001). The laboratory results indicate that the calcium and phosphate salts delivered by the remineralizing Enamelon dentifrice increase the bioavailability of fluoride to substantially exceed that of the clinically proven standard dentifrice.

Remineralization by fluoride enhanced with calcium and phosphate ingredients.

The effectiveness of fluoride ions provided by toothpastes and mouthrinses in promoting remineralization can be limited by the low concentrations of calcium and phosphate ions in saliva. The purpose of this study was to determine whether improved remineralization can be obtained from toothpastes or mouthrinses that simultaneously deliver fluoride, calcium, and phosphate ions from dual-dispensing systems. Enamel specimens with artificial lesions between 60 and 90 microns deep were cycled 15 times through demineralization for 30 minutes, treated for 5 minutes with an experimental or control fluoride toothpaste or mouthrinse, and remineralized for 60 minutes. In the toothpaste study, surface hardness increased by 11.5 +/- 9.2 and 2.7 +/- 3.6 Vickers hardness units, and enamel fluoride content was 5984 +/- 521 ppm and 3971 +/- 531 ppm for the experimental and control fluoride toothpastes, respectively. Remineralization was confirmed by x-ray microradiography. In the mouthrinse study, surface hardness increased by 8.8 +/- 7.7 and 2.2 +/- 3.7 Vickers hardness units, and enamel fluoride content was 6111 +/- 1078 ppm and 3160 +/- 364 ppm for the experimental and control fluoride mouthrinses, respectively. Use of a non-fluoride control mouthrinse led to a decrease in surface hardness of 3.7 +/- 5.2 Vickers hardness units despite a fluoride content of 402 ppm. The results demonstrate that calcium and phosphate supplementation in a toothpaste or mouthrinse can improve remineralization and increase fluoride uptake.

Strengthening of tooth enamel by a remineralizing toothpaste after exposure to an acidic soft drink.

The effect of remineralizing and conventional toothpaste treatments on the hardness of intact and acid soft drink-etched enamel were assessed in a laboratory study. The remineralizing toothpaste (Enamelon Toothpaste) used in the study contains NaF, and simultaneously provides dissolved calcium, phosphate and fluoride ions. The conventional toothpaste contains NaF in a silica base. Sound extracted maxillary human incisors, mounted in epoxy resin with the facial incisal two-thirds exposed, were polished with 0.3 mu alumina. Groups of ten teeth were exposed to either twenty 5-minute treatments with an acid soft drink (pH 2.4), remineralizing or conventional fluoride toothpaste, or to twenty alternating cycles of a 5-minute protective treatment with either the remineralizing or conventional toothpastes, followed by 5-minute exposures to the acid soft drink, or to 20 five-minute exposures to the acid soft drink followed by 20 five-minute restorative treatments with the remineralizing or conventional toothpastes. Knoop Hardness measurements were made before and after treatment using a 500 g load and 15-second dwell time. Acid soft drink exposure produced a 15.4% drop in hardness compared with 4.9% and 1.6% hardness increases due to treatments of intact enamel with the remineralizing and conventional toothpastes, respectively. Protective treatments using the remineralizing and conventional toothpastes significantly reduced the drop in hardness due to acid soft drink exposure to 3.3% and 6.2%, respectively. Restorative treatments by the remineralizing and conventional toothpastes significantly increased the hardness of the acid soft drink-weakened enamel by 12.1% and 7.3%, respectively. Both toothpastes were effective in inhibiting damage due to acid soft drink exposure, but the remineralizing toothpaste was more effective in hardening intact and decalcified enamel than the conventional toothpaste (p < 0.05).

Cariostatic effect of a two-part fluoride dentifrice in rats.

This study compared the cariostatic effect of a two-part, fluoride-calcium-phosphate-containing prototype dentifrice (containing 1100 ppm F) to a conventional, clinically proven effective "gold standard" (1100 ppm F, USP Standard) and an Enamelon placebo dentifrice (0 ppm F) using a rat model. Three groups of 18 Crl:CDR(SD)BR rats were inoculated with S. sobrinus 27352 and fed MIT-200 for 35 days in a programmed feeder. Double-deionized water (DDW) was given ad libitum. The rats were treated twice daily with one two-part dentifrice. Just prior to treatment, each of the two parts of dentifrice were mixed 1:1 and applied undiluted. The rats were euthanized and their mandibular molars scored for caries using the Keyes quantification method. Shrestha SNP caries scores were then calculated. Non-parametric comparisons were done among treatments at the 0.05 level of significance using analyses based on ranks. The mean Shrestha SNP Caries Scores +/- standard deviations for the prototype dentifrice, USP standard and Enamelon placebo were 84.9 +/- 62.8, 101.3 +/- 66.3, and 181.2 +/- 100.1, respectively. Scores for the 1100 ppm F prototype treatment were significantly lower than the USP Standard and the Enamelon placebo. These results indicate that the new prototype dentifrice, containing fluoride-calcium-phosphate, increased the anti-caries efficacy in a rat model when compared with a fluoride-containing USP Standard dentifrice.

An in vitro assessment and a pilot clinical study of electrical resistance of demineralized enamel.

Electrical resistance measurement was evaluated in vitro and in vivo as a method for comparing the remineralizing performance of toothpastes. In the in vitro study, areas of sound enamel on 12 unrestored, mature, extracted human molars and bicuspids, with electrical resistance readings greater than 99.99 M omega, were demineralized to an electrical resistance of 1 to 4 M omega. The teeth were divided into three groups. The change in electrical resistance was measured following a 15 cycle regimen of treatment, demineralization and salivary soaking. Treatments were five-minute exposures to either a 1:2 slurry in saliva of Enamelon (E), a remineralizing fluoride-toothpaste also containing soluble calcium and phosphate ions, a 1:2 slurry in saliva of Crest (C), a conventional fluoride toothpaste (P), or to saliva alone. Demineralization was performed with a 30-minute exposure to 0.1 M lactic acid 50% saturated with calcium hydroxyapatite. The salivary soaking was 1 hour in duration. The mean electrical resistance of the E, C and the saliva treated sites was 63.9 +/- 4.3, 37.6 +/- 9.5 and 2.1 +/- 0.7 M omega, respectively. The final resistance was statistically different for each group (p < 0.05). A pilot clinical study was then conducted to assess the electrical resistance technology in vivo. Eighteen adult subjects with at least one site of early enamel caries with an electrical resistance between 1.0 M omega and 20.00 M omega were randomly assigned to either Enamelon, Crest, or a non-fluoride placebo toothpaste and asked to brush twice daily. After three months, the mean resistance of the test sites was 23.57 M omega for E, 9.61 M omega for C and 13.24 M omega for P. However, the mean resistance changes did not proceed consistently over time. At the end of the study, the electrical resistance measurements on four sites out of twelve in Group E were suggestive of remineralization, whereas measurements on one site out of ten were suggestive of remineralization in Group C and two or three sites out of twelve were suggestive of remineralization in Group P. Progression of demineralization was possibly indicated in only one site, which was in Group C. There were insufficient subjects for statistical significance in the pilot clinical study. There were apparent problems with the variability of some measurements between visits in the in vivo study. Overall, however, the results of both studies indicate that with modifications to the equipment, electrical resistance measurements may be a means of comparing the remineralization performance of toothpastes.

Treatment of orthodontic white spot lesions with a remineralizing dentifrice applied by toothbrushing or mouth trays.

This pilot study investigated the effect of a remineralizing fluoride dentifrice (Enamelon) on newly formed incipient carious lesions using two methods of application. Teenage orthodontic patients with obvious white spot lesions on their teeth were selected to begin treatment within 30 days after debanding. At baseline, the surface enamel of the test teeth was cleaned by air etching with 50 microns alumina at 150 psi. Lesion size (mm2) was measured using a calibrated periodontal probe and surface appearance was quantified as shiny (0), dull (1), or chalky (2). Twice daily for 3 months, one group with a total of 27 lesions brushed with the remineralizing dentifrice, while a second group with 41 total lesions brushed and used a mouth tray to apply the paste directly to the lesions for 5 min. In order to promote treatment compliance, test group assignment was based on subject and parental preference. After 1, 2, and 3 months, lesion size was reduced by 5% (ns), 10% (p < 0.05) and 22% (p < 0.01), respectively, for the brushing group, and 16% (p < 0.05), 37% (p < 0.01) and 30% (p < 0.01) for the combined brushing and tray group, respectively. The dull appearance of the lesions treated by brushing improved slightly over 3 months. However, the lesions receiving combined brushing and tray applications became significantly (p < 0.01) less dull by 28%, 44% and 61% after 1, 2, and 3 months, respectively, indicating the formation of a shiny, intact surface layer. In conclusion, brushing with a remineralizing dentifrice significantly reduced the size of new orthodontic white spots within 2 months, while brushing combined with topical tray applications reduced lesion size within 1 month with concomitant formation of a shiny enamel surface layer. Thus, the combined brushing and mouth tray treatment significantly accelerated the remineralization process.

Clinical evaluation of the effect of a remineralizing toothpaste on dentinal sensitivity.

Dentinal hypersensitivity is a common dental problem without a satisfactory solution. Most therapies have focused on either trying to block the stimulation of dentinal nerves or on sealing open dentinal tubules. This study evaluated, in a double blind clinical trial, the effect of Enamelon, a dentifrice containing sodium fluoride, calcium salts and phosphate salts (calcium separated from the phosphate and fluoride by a plastic divider in the tube to prevent interaction) on dentinal hypersensitivity over an 8-week period. A conventional OTC dentifrice containing NaF without calcium and phosphate enhancement served as the control. A third dentifrice, containing sodium monofluorophosphate enhanced by calcium and phosphate salts, was also tested. Based upon subjective anecdotal information, net numbers of sensitive teeth which became non-sensitive, and a logit analysis of the change in the proportion of sensitive teeth over the study time period, Enamelon was the most effective product, and the OTC control the least effective.

Caries prevention in the 21st century.

While the incidence of caries has decreased during the past 50 years because of the introduction of water fluoridation and fluoride toothpastes, it is still widespread. Improved therapies, using topical treatments to replace lost calcium and phosphate minerals from early carious lesions, will reduce the need for surgical intervention in the future. Early caries detection techniques currently being developed will allow dentists to maximize the usefulness of these treatments.