A study of radiogallium aqueous chemistry: in vitro and in vivo characterisation of (67) Ga-hydrolysed-stannous fluoride particles.

The objective of this study was to explore the aqueous chemistry of gallium using (67) Ga-chloride starting material, by radiolabelling hydrolysed(h)-stannous fluoride particles and then characterising the optimal formulation for radiochemical purity (RCP) and radioactive particle size distribution in vitro. The pilot reactions determined stannous fluoride was added to (67) Ga-acetate under nitrogen and then heated at 100 °C for 20 min to achieve ≥95% RCP and (67) Ga-particles were >3 µm in diameter. A high radioactive concentration of (67) Ga-h-SnF2 particles could be prepared similarly in ≥97% RCP with 74% as 3-5 µm and 26% >5 µm in diameter. The latter formulation had larger particles than (99m) Tc-h-SnF2 colloid (96% of 1-3 µm), and it resulted in a rat biodistribution of 41% in the lungs, 41% in the liver plus spleen and 18% in the carcass at 20 min after injection. The carcass activity was attributed to bone marrow and some (67) Ga-transferrin formed in blood. Isolated mixed human leucocytes were radiolabelled with (67) Ga-h-SnF2 particles in 100% efficiency, and the (67) Ga-cells did not release soluble (67) Ga(3+) at room temperature over 3 h. The (67) Ga-h-SnF2 particle formulation could find a use in labelling leucocyte cells for in vivo homing studies when delayed animal imaging is required.

Protective effects of SnF2 - Part II. Deposition and retention on pellicle-coated enamel.

UNLABELLED: Deposition of an acid-resistant barrier onto enamel represents a potentially superior means for delivering protection against dietary, erosive acid challenges. PURPOSE: The purpose of this study was to demonstrate the ability of a stabilised stannous fluoride (SnF2 ) dentifrice to: (1) deposit a SnF2 barrier layer onto pellicle-coated enamel surfaces; (2) increase the intensity of the barrier layer over time; and (3) be retained on the enamel surface for hours after product use. METHODS: Squares of human enamel were exposed to pooled saliva for 1 hour (pellicle formation) and separated into six sets. Set 1 was treated with the supernatant of a 1:3 slurry of the test dentifrice (Crest(®) Pro-Health(®) : water for 2 minutes), then rinsed. Set 2 was treated in the same manner and then placed into saliva (6 hours). Set 3 was cycled through seven repeated treatments. Set 4 was treated for seven cycles and then placed into saliva (6 hours). Set 5 was a water control, and set 6 was a water control that remained in saliva for 6 hours. Surface analysis of specimens was done using laser ablation Inductively Coupled Plasma Mass Spectroscopy (ICP-MS). RESULTS: Deposition of a barrier layer was demonstrated, beginning with the initial treatment, with Sn (using isotopes (117) Sn + (120) Sn) measured on the enamel surface as the reference marker. Deposition of the barrier layer was greater after seven cycles, and the retention of this layer was highly significant (P = 0.05, anova: 6 hours). CONCLUSIONS: This study confirms that: (1) the stabilised SnF2 dentifrice deposits a barrier layer onto the enamel surface, beginning with the first use of the product; (2) this barrier is enhanced following multiple treatments; and (3) the barrier layer is retained on the enamel surface for hours after product use.

Fluoride bioavailability in saliva and plaque.

BACKGROUND: Different fluoride formulations may have different effects on caries prevention. It was the aim of this clinical study to assess the fluoride content, provided by NaF compared to amine fluoride, in saliva and plaque. METHODS: Eight trained volunteers brushed their teeth in the morning for 3 minutes with either NaF or amine fluoride, and saliva and 3-day-plaque-regrowth was collected at 5 time intervals during 6 hours after tooth brushing. The amount of collected saliva and plaque was measured, and the fluoride content was analysed using a fluoride sensitive electrode. All subjects repeated all study cycles 5 times, and 3 cycles per subject underwent statistical analysis using the Wilcoxon-Mann-Whitney test. RESULTS: Immediately after brushing the fluoride concentration in saliva increased rapidly and dropped to the baseline level after 360 minutes. No difference was found between NaF and amine fluoride. All plaque fluoride levels were elevated after 30 minutes until 120 minutes after tooth brushing, and decreasing after 360 minutes to baseline. According to the highly individual profile of fluoride in saliva and plaque, both levels of bioavailability correlated for the first 30 minutes, and the fluoride content of saliva and plaque was back to baseline after 6 hours. CONCLUSIONS: Fluoride levels in saliva and plaque are interindividually highly variable. However, no significant difference in bioavailability between NaF and amine fluoride, in saliva, or in plaque was found.

Mechanism of action of tin-containing fluoride solutions as anti-erosive agents in dentine - an in vitro tin-uptake, tissue loss, and scanning electron microscopy study.

Solutions containing tin and fluoride exhibit remarkable anti-erosive properties with tin ions as a major agent. To elucidate its mechanism of action in dentine, the tin uptake on and in the tissue was investigated and related to histological findings and substance loss. Samples were treated twice daily, each treatment lasting for 2 min, with fluoride solutions [pH 4.5; 1,500 parts per million (p.p.m.) F] containing 2,100, 1,400, or 400 p.p.m. Sn as SnCl(2). In experiments 1 and 2, samples were eroded with citric acid (pH 2.3) six times each day, each treatment lasting for 5 min; in experiment 2, the demineralized organic matrix was continuously digested by collagenase; in experiment 3, no erosive challenges were performed. Sample surfaces and cross-sections were investigated using energy dispersive X-ray spectroscopy, scanning electron microscopy, and profilometry. Surface retention of tin was found in almost all treatment groups and was highest in experiment 2. On cross-sections, tin was retained within the organic matrix; in mineralized areas, tin was found mainly within a depth of 10 mum. Test solutions inhibited substance loss significantly; in experiment 2, the effect was dose-dependent. Erosion inhibition seemed to depend mainly on the incorporation of tin in the mineralized dentine when the organic portion was preserved, but on surface precipitation when the organic portion was continuously digested.

Fluoride penetration from toothpastes into incipient enamel erosive lesions investigated using dynamic secondary ion mass spectrometry.

OBJECTIVE: The primary aim of this study was to assess the utility of dynamic secondary ion mass spectrometry (DSIMS) as a convenient and sensitive technique for determining fluoride uptake and distribution into incipient human enamel erosive lesions in vitro. A secondary aim was to correlate the extent of lesion rehardening following treatment with a toothpaste slurry, with relative fluoride uptake determined by DSIMS. The final aim was to compare fluoride uptake by incipient lesions treated with toothpastes containing different sources of fluoride using DSIMS. METHODS: Relative fluoride uptake into the surface and body of enamel erosive lesions was monitored by DSIMS as a function of fluoride concentration in a series of formulation-matched experimental pastes. Fluoride uptake into lesions that had been subjected to treatment with different toothpaste slurries in a single-treatment enamel lesion rehardening model was also determined, and its relationship with regard to the extent of rehardening and also the fluoride source investigated. RESULTS: Fluoride uptake by incipient erosive lesions treated with toothpastes containing NaF was quantitatively compared by DSIMS and found to be directly proportional to the fluoride concentration over the studied range (0-1400 ppm). Lesion repair observed in a single-treatment lesion rehardening model was positively correlated with the extent of fluoride uptake by the treated lesions. DSIMS was also able to show differences between commercial toothpastes containing different sources of fluoride and their ability to deliver the fluoride into the body of the lesion. The detrimental effect of sodium hexametaphosphate (NaHMP) present in Crest Pro-Health formulations previously reported in the single-treatment lesion rehardening model was also evident from the DSIMS elemental line scans obtained from the lesion cross-sections. CONCLUSION: DSIMS has been shown to be a powerful selective technique for quantifying relative fluoride uptake into enamel erosive lesions, and determining the extent and depth of lesion penetration. The relative efficacy of toothpastes containing fluoride from a variety of sources in the single-treatment lesion rehardening study is positively correlated with fluoride uptake and penetration determined by DSIMS.

Laboratory assessment of the anticaries potential of a new dentifrice.

OBJECTIVE: The aim of the present study was to investigate the anticaries potential of a new sodium fluoride dentifrice in comparison to two commercial dentifrices containing different fluoride compounds by determining enamel fluoride uptake (EFU) and early caries lesion remineralization (REM) in an established in vitro caries remineralization/demineralization pH cycling model. METHODS: Test products were: new dentifrice formulation in a fluoride dose-response (0; 675; 1426 ppm F as sodium fluoride [NaF-0; NaF-675; NaF]); Elmex Kariesschutz (1400 ppm F as amine fluoride [AmF]); and Oral-B Pro-Expert (1450 ppm F-1100 ppm F as stannous fluoride and 350 ppm F as sodium fluoride [SnNaF]). Artificial caries-like lesions were formed in human enamel specimens by immersion in lactic acid buffer (LA). Specimens were then subjected to a daily cycling regime for 20 days comprising four one-minute dentifrice slurry treatments (prepared in pooled human saliva), and one four-hour LA challenge and remineralization in pooled human saliva. After 20 days, REM was evaluated as the change in surface Vickers microhardness from lesion baseline and EFU using the microdrill technique. The data were analyzed using ANOVA. RESULTS: A good fluoride dose-response was established for EFU and REM, with NaF delivering greater EFU and REM than NaF-675, which was superior to NaF-0 (p < 0.05). The new dentifrice NaF also showed greater EFU and REM than AmF and SnNaF (p < 0.05). In EFU, AmF and SnNaF were as efficacious as NaF-675 and superior to NaF-0 (p < 0.05). AmF and NaF-675 were also comparable in REM, whereas both products exhibited superior REM vs. SnNaF (p < 0.05), which was superior to NaF-0 (p < 0.05). CONCLUSION: The present study has demonstrated that fluoride dentifrices vary in their capability of enhancing anticaries potential as determined using an established in vitro caries cycling model. The new dentifrice NaF showed superior predicted anticaries potential compared to the two commercial dentifrices AmF and SnNaF in this model, which demonstrates the importance of fluoride compound and formulation excipients on driving anticaries potential in vitro.

Anticaries potential of commercial dentifrices as determined by fluoridation and remineralization efficiency.

AIM: The aim of this in vitro study was to investigate fluoride uptake in human enamel after use of commercially available toothpastes containing different fluoride compounds, or combinations of fluoride actives formulated into a single product, as a means of determining the efficiency of each formula for delivering caries preventing fluoride to demineralized (caries active) enamel. METHODS AND MATERIALS: Four test dentifrices and two controls were assessed and placed in groups as follows: Group 1: Lacer (Spain); Group 2: Positive control-USP Reference Standard 1100 ppm F; Group 3: Fluocaril Bi-Fluoré 250 (France); Group 4: Colgate Fluor Active (Denmark); Group 5: Elmex (France); and Group 6: A placebo (formulated the same as the USP Reference Standard toothpaste with the exception that it contained < 1 ppm F). Cores 3 mm in diameter were removed from erupted human enamel specimens (extracted by local oral surgeons for orthodontic reasons) and stored in 1% Thymol solution prior to use. They were ground and polished to remove the natural fluoride rich enamel layer, then exposed to a demineralization solution, and assessed for surface microhardness to enable randomization for use in the study. Each group of five specimens underwent a daily pH cycling procedure that involved exposure to pooled human saliva (refreshed three times daily). The groups were then exposed to dentifrice slurries four times daily for one minute per exposure and to a demineralization solution for three hours. The cycling procedure was repeated for five days. Specimens were again analyzed for surface microhardness and fluoride uptake upon completion of five days of treatment. RESULTS: Average surface hardness: Groups 2 and 3 showed a statistically significant greater (p<0.05) change indicating greater remineralization compared to all other groups. The average change was 23.45 for Group 2 and 22.65 for Group 3. All other groups had changes ranging from 4.25-8.62. No other statistically significant differences were observed between groups. Fluoride uptake results: Groups 2 and 3 showed statistically significantly greater fluoride uptake versus all other groups (p<0.05). Groups 1 and 5 were significantly different from Group 6. No other statistically significant differences were observed for either analysis. CONCLUSIONS: Of the marketed products included in the study, the Fluocaril Bi-Fluoré 250 product formulation provided both the highest level of fluoride uptake and mineralization to the demineralized enamel. The clinical significance of these in vitro results is the confirmation Fluocaril Bi-Fluoré 250 is effective at remineralizing enamel caries lesions.

Influence of carbamide peroxide on enamel fluoride uptake.

OBJECTIVE: Aim of the study was to evaluate the influence of carbamide peroxide (CP) on enamel fluoride uptake by comparing enamel fluoride uptake from a 1% amine fluoride (AmF) gel with the fluoride acquisition from a 10% carbamide peroxide agent supplemented with 1% AmF. MATERIALS AND METHODS: Three enamel cylinders (4mm in diameter) were prepared from the buccal surfaces of 60 bovine incisors. One sample of each tooth was used for determination of baseline fluoride content of the respective tooth. The two remaining samples were allocated to the experimental series 1 or 2, respectively. Each series consisted of five experimental groups (A-E, n=12) and differed with respect to the length of the treatment period with the gels (A-D). The experimentally designed gels (pH 5.5) used in the study were as follows: A (10% CP), B (10% CP, 1% F(-) as AmF), C (1% F(-) as AmF), D (no CP, no F(-)) and were formulated on the same basis. The enamel samples were covered for 4h with the respective gel at 37 degrees C and were then transferred to artificial saliva for 20 h (series 1). The samples of group E served as controls and were not treated with a gel. In series 2, treatment with the gels and storage in saliva was conducted seven times. Finally, the samples were assessed for KOH-soluble and structurally bound fluoride. RESULTS: Only the enamel samples treated with the fluoridated bleaching gel (group B) and with the amine fluoride gel (group C) exhibited significant fluoride acquisition. Thereby, both gels showed significantly lower uptake in series 1 as compared to series 2. Both KOH-soluble and structurally bound fluoride acquisition was significantly higher in group C than in group B. CONCLUSION: Treatment with a carbamide peroxide gel supplemented with amine fluoride causes less fluoride acquisition in enamel than a pure amine fluoride gel. Under the conditions of the study, it is assumed that carbamide peroxide seems to influence enamel fluoride uptake.

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

UNLABELLED: 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. IN CONCLUSION: 8% SnF2 is expected to have greater anticaries property from the high fluoride releasing property for prolonged period of time.

Intra-oral retention of fluoride by bovine enamel from amine fluoride toothpaste and 0.4% amine fluoride liquid application.

The purpose of this study was to compare in vivo fluoride accumulation in enamel and in enamel lesions from a single topical fluoride application and daily toothbrushing with a fluoride dentifrice. Amine fluoride preparations were used for both products. Intra-oral appliances with bovine enamel specimens were worn by volunteers during a period of seven weeks. After this period, the specimens were analyzed for fluoride uptake and change in demineralization susceptibility. The results demonstrated that lesions had a high fluoride uptake capacity. Fluoride content values increased by 25-30 micrograms/cm2 during a single topical application, as compared with 10-15 micrograms/cm2 during seven weeks of toothbrushing. About half the fluoride acquired as a result of topical treatment was lost during subsequent exposure to the oral fluids when no further fluoride supplementation was given. The uptake of fluoride by sound enamel was comparatively small, regardless of the use of fluoride dentifrice or application. The presence of mature plaque at the time of fluoride application did not affect the amounts of fluoride delivered. Acid susceptibility tests showed that the enamel solubility exhibited a negative correlation with fluoride content of the specimens.

An in vivo study of microhardness and fluoride uptake in partially demineralized human enamel covered by plaque.

In this investigation, microhardness changes in partially demineralized human enamel were studied after in vivo use of fluoridated toothpaste systems. Flattened enamel specimens were demineralized in vitro and subsequently positioned in approximal positions in the prostheses of 27 participants for three weeks; the samples were plaque-covered in vivo. After brushing for one week with a non-fluoridated paste to achieve an in vivo equilibrium, participants brushed with an assigned product for a two-week period. This test was a six-way cross-over design which used randomization of subjects. Five fluoridated and one non-fluoridated paste were tested. Knoop hardness measurements were carried out on sound and on in vitro demineralized enamel, and after in vivo exposure of the enamel to the dentifrice treatments. The results showed that during the two weeks of in vivo exposure to the fluoride products, net rehardening of the demineralized enamel did not occur, and no correlation was observed between fluoride uptake into the demineralized enamel and changes in microhardness. That we failed to observe rehardening may be due to the fact that the duration of this study was too short for any net remineralization to have occurred, especially because the samples were constantly covered with plaque. Other possibilities, such as the type and/or severity of the lesions used in this study, may account for the lack of rehardening.

99mTc-SnF2 colloid "LLK": particle size, morphology and leucocyte labelling behaviour.

99mTc-SnF2 colloid (Radpharm LLK) leucocyte labelling agent is used in whole blood, exploiting phagocytosis. The objectives of this work were to optimize leucocyte labelling in leucocyte-enriched plasma, and to investigate: (i) the effect of temperature and other factors on labelling efficiency; (ii) the selectivity for different leucocyte types; (iii) the viability of the labelled cells and efflux of the radiolabel; and (iv) the physical characteristics of the colloid. Density gradient centrifugation was used to investigate the labelling efficiency, cell selectivity and efflux, Trypan blue to study the viability, and laser scattering, electron microscopy and membrane filtration to investigate particle size and morphology. Particles appeared as loose, coiled, chain-like aggregates of much smaller particles (<0.05 microm). The aggregate diameter ranged from <0.1 to >5 microm and increased with time. The distribution of radioactivity amongst the particle sizes varied widely. The labelling efficiency in leucocyte-rich plasma was enhanced at 37 degrees C compared to room temperature, and by centrifuging during labelling. The selectivity for different leucocyte types varied markedly between batches and blood samples, in some cases showing preference for mononuclear cells and in others for granulocytes. Viability was excellent and comparable with 99mTc-hexamethylpropyleneamine oxime (99mTc-HMPAO)-labelled cells. A significant fraction of radiolabel, comparable to that observed with 99mTc-HMPAO, was lost from leucocytes during incubation in vitro over 4 h. Thus, 99mTc-SnF2 is a convenient, efficient labelling agent for leucocytes, but shows variable cell selectivity which may be linked to particle size variability, and there is significant efflux of radioactivity from labelled cells.

Imaging of abdominal infection using 99m Tc stannous fluoride colloid labelled leukocytes.

Radiolabelling of leukocytes using labelled phagocytosed technetium-99m (99mTc) colloidal radiopharmaceuticals has been reported as a method for imaging infection. This in vivo study compares the use of leukocytes labelled using 99mTc stannous fluoride colloid with leukocytes labelled using indium-111 (111In) oxinate. A total of 26 patients (10 male, 16 female; mean age 52 years, range 23-88 years) referred for the investigation of possible infection were studied using both leukocyte labelling methods simultaneously. Images were acquired 4h and 24h after re-injection of the labelled cells. The images were evaluated qualitatively by two nuclear medicine physicians. The results show a high degree of concordance between the techniques: 11 of the 28 images showed a focus of leukocyte accumulation with both techniques at 24h, and 13 out of 28 showed a normal appearance at 24h with both methods. In four cases the results were discordant; the 99mTc stannous fluoride colloid labelled leukocytes gave a false positive appearance at 24h in three patients and a false negative in one. In conclusion, colloid labelling of leukocytes offers a sensitive method for the detection of infective foci coupled with the high resolution imaging offered by 99mTc. It has the advantage over other in vitro labelling methods of being a simpler, non-labour-intensive procedure employing whole blood, and its use should be considered by departments that have limited facilities for in vitro leukocyte labelling.

Nuclear medicine and infection detection: the relative effectiveness of imaging with 111In-oxine-, 99mTc-HMPAO-, and 99mTc-stannous fluoride colloid-labeled leukocytes and with 67Ga-citrate.

With a current annual mortality rate of around 35% worldwide, infection remains a significant concern, and the diagnosis and localization of infectious foci is an important health issue. As an established infection-imaging modality, nuclear medicine plays a vital health-care role in the diagnosis and subsequent effective treatment of this condition. Despite the development of several newer radiopharmaceuticals, (67)Ga and leukocyte imaging procedures have maintained their established place for infection. Several techniques in nuclear medicine significantly aid infection diagnosis, including imaging with (111)In-oxine-, (99m)Tc-hexamethylpropyleneamine oxime-, and (99m)Tc-stannous fluoride colloid-labeled leukocytes and with (67)Ga-citrate. Each radiopharmaceutical has specific advantages and disadvantages that make it suitable to diagnose different infectious processes (e.g., soft-tissue sepsis, inflammatory bowel disease, osteomyelitis, occult fever, fever of unknown origin, and infections commonly found in immunocompromised patients). After finishing this article, the reader should be able to identify the properties of an ideal radiopharmaceutical for infection imaging, list a range of available infection-imaging radiopharmaceuticals, compare the relative results of a range of radiopharmaceuticals used internationally to detect infection in the body, understand several common infectious processes that can be diagnosed using nuclear medicine techniques, and select an appropriate radiopharmaceutical to image a range of infectious processes.

Clinical effects and possible mechanisms of action of stannous fluoride.

Stannous fluoride was frequently used as a vehicle for fluoride in preparations used in caries prophylaxis in the 1960s and 1970s. At present it is not much used, although extensive research during the last two decades has established that stannous fluoride possesses several interesting properties which demonstrate that it deserves to be used in the prophylaxis against both gingivitis and caries. In the following, a review of the clinical properties of stannous fluoride is presented, together with a discussion of its merits compared with other fluoride vehicles in current use.

Recent advances in stannous fluoride technology: antibacterial efficacy and mechanism of action towards hypersensitivity.

Stannous fluoride (SnF2) is highly susceptible to oxidation and hydrolysis but both anhydrous and aqueous preparations can be well established by proper formulation. When stability in aqueous preparations is achieved by the use of certain strong complexing agents, reduced antibacterial activity is observed which may be attributed to reduced bioavailability of the stannous ion. In contrast, an anhydrous SnF2 preparation maintains stannous ion in a stable but, uncomplexed form. This preparation displays antibacterial activity in saliva and delivers stannous ion which is absorbed onto surfaces making them less susceptible to plaque formation for an extended period of time (hours). When this anhydrous preparation is brushed onto dentine in vitro or in situ, one observes a nearly complete coverage of the dentine surface and occlusion of tubules by a tin-rich surface deposit. This finding indicates that the observed clinical efficacy of this preparation at relieving hypersensitivity is due to occlusion of tubules by a mixture of low solubility complexes of tin. A water-based SnF2 preparation containing strongly complexed stannous ions does not form a surface coating on dentine in vitro suggesting that this preparation may not be optimal for treating hypersensitivity. Overall, the findings indicate that the stannous ions in a SnF2 preparation must be maintained in a stable, bioavailable form for optimal efficacy against plaque and hypersensitivity to be obtained. The results suggest that these properties are provided by stable anhydrous preparations but are difficult to achieve simultaneously in aqueous preparations. When properly formulated, stannous fluoride preparations can provide multiple oral therapeutic benefits.

Anticaries efficacy of a new dentifrice for hypersensitivity.

PURPOSE: To evaluate the expected anticaries efficacy of a new dentifrice containing stannous fluoride as the anticaries agent and potassium nitrate as the antihypersensitivity agent using a series of laboratory and animal studies. METHODS: Four surrogate studies were performed in this assessment including fluoride uptake in sound enamel, enamel solubility reduction, fluoride bioavailability and animal caries. RESULTS: Each of these studies indicated the new dentifrice for hypersensitivity (Colgate Sensitive Maximum Strength) was effective in inhibiting the caries process. The data demonstrate that this new dentifrice is predicted to be highly effective against caries and equivalent to a positive control dentifrice.

Anticaries efficacy of an improved stannous fluoride toothpaste.

A series of laboratory and animal studies were conducted to confirm the anticaries potential of a new, stabilized stannous fluoride (SnF2) dentifrice relative to clinically proven SnF2 controls. Included in this series of assessments were fluoride uptake into demineralized human enamel, remineralization/inhibition of demineralization for both human enamel and roots, and animal caries studies. Each of these studies demonstrate the new, stabilized SnF2 dentifrice (Crest Gum Care toothpaste) is effective at inhibiting and reversing the caries process. These data confirm that this new dentifrice, formulated with a combination of SnF2, and hydrated silica, is predicted to be highly effective against caries. These tests predict that this new stabilized SnF2 dentifrice (Crest Gum Care toothpaste) provides a level of anticaries activity that is equivalent to Crest Regular toothpaste, a sodium fluoride (NaF)/silica product. The data suggest that this new formulation provides enhanced anticaries efficacy relative to previous, unstabilized SnF2 formulations as a result of improved fluoride bioavailability.

[Treatment of dentin sensitivity with stannous fluoride gel. Electron microscopic study and evaluation of dentin permeability]. / Trattamento della sensibilità dentinale con fluoruro stannoso in gel. Studio al microscopio elettronico e valutazione della permeabilità dentinale.

Dentine hypersensitivity still represent a major clinical problem only partially solved. The presence of exposed opened dentinal tubules has been demonstrated increase the dentine permeability and it is the responsible for pain and sensitivity. Stannous fluoride solution has been recently proposed to reduce dentine hypersensitivity. The aim of the present study was to evaluate the dentinal permeability of a new stannous fluoride gel proposed for the therapy of dentine hypersensitivity. Human extracted teeth have been used and mounted and connected with a hydraulic pressure apparatus working at 1 psi (70 cm of water pressure). It was calculated the permeability of untreated smear layer, treated smear layer (after gel application) and after acidic treatment. It was observed that gel treatment was able to reduce dentine permeability. Scanning electron microscopy demonstrated the presence of a homogeneous smear layer after treatment with gel. This in vitro study confirms that stannous fluoride treatment has the capacity to modify dentine permeability of sensitive dentine.

An in vitro assessment of fluoride uptake by tooth enamel from four different fluoride dentifrices.

AIM: The aim of this study was to evaluate fluoride uptake by tooth enamel with four different fluoride dentifrices. STUDY DESIGN: Sixty human premolars extracted for orthodontic purpose were selected for the study. The teeth were covered with nail varnish leaving a window of 4 × 4 mm on the enamel surface of the buccal and lingual sides. The teeth were demineralised and were divided into four groups with 15 teeth in each group. The buccal window served as experimental and the lingual as control. The teeth were immersed in toothpaste slurry containing: sodium fluoride (Group A); sodium monofluorophosphate (Group B); stannous fluoride (Group C) and amine fluoride (Group D). The fluoride content in the etched superficial enamel layer in the windows was analysed using a fluoride ion-specific electrode. RESULTS: Within the parameters of this study, the uptake of fluoride was statistically significant in Group D (p < 0.05). The uptake of fluoride by tooth enamel in an increasing order was Group A < Group B < Group C < Group D. CONCLUSION: The study showed that enamel treated with amine fluoride had the highest fluoride uptake.