Non-fluoridated Dentifrice Research Articles

Remineralizing Potential of Low-fluoridated, Nonfluoridated and Herbal Nonfluoridated Dentifrices on Demineralized Surface of Primary Teeth: An In Vitro Study.

AimThe aim of this in vitro study is to evaluate the remineralizing potential of commercially available low-fluoridated, nonfluoridated, and herbal nonfluoridated child formula dentifrices on primary teeth.Materials and methodsTotal of 36 primary teeth were placed in the demineralizing solution for 96 hours to produce artificial carious lesions of approximately 100 μm depth, and then cut longitudinally into 30 sections of 100–150 μm thickness and randomly assigned to three groups. Sections were treated with low-fluoridated, nonfluoridated, and herbal nonfluoridated dentifrice. Lesions were evaluated using polarized light microscopy.ResultsIntragroup comparison of mean lesion depth from pretreatment to posttreatment among the three study groups revealed that maximum reduction in lesion depth was found to be in group I (low-fluoridated) followed in descending order by group III (herbal nonfluoridated) and group II (nonfluoridated), respectively.ConclusionGroup I (low-fluoridated) and group III (herbal nonfluoridated) demonstrated remineralization of carious lesions by virtue of a decrease in lesion depth, whereas group II (nonfluoridated) showed an increase in lesion depth.Clinical significanceFluoride dentifrices are the most widely used products that deliver topical fluoride to the oral environment. The major drawback is the risk of dental fluorosis, which occurs because of ingestion of dentifrices, in preschool children. This necessitates use of preventive measures which include (1) reducing the amount of toothpaste used, (2) supervised brushing in preschool children and (3) developing low-fluoride toothpastes for minimizing risk of dental fluorosis. Further dental professionals must investigate effectiveness of increasingly popular “Herbal” products.How to cite this articleTiwari S, Saha S, Dhinsa K, et al. Remineralizing Potential of Low-fluoridated, Nonfluoridated and Herbal Nonfluoridated Dentifrices on Demineralized Surface of Primary Teeth: An In Vitro Study. Int J Clin Pediatr Dent 2022;15(3):251-257.

Relationships between parental education, choice of child dentifrice, and their children's caries experience.

The influence of parental education, choice of child dentifrice, and its impact on their children's dental caries experience remain unclear. To investigate (a) dentifrice types used by Australian pre-school children, (b) demographic factors that influence parents' dentifrice choice, and (c) whether dentifrice type is related to pre-schooler's caries experience. 155 parent-child dyads were recruited from five random metropolitan childcare centres. Parents completed a questionnaire recording relevant demographics and child dietary preferences, oral hygiene practice, and dental visits. One calibrated operator performed a clinical examination of their pre-schooler for evidence of carious lesions. Data were analysed, and comparisons between variables made using chi-square tests and regression models. 50% of pre-schoolers used <1000ppm fluoride dentifrice and 29% used non-fluoridated dentifrice. Higher parental education level was associated with the use of non-fluoridated dentifrice (P=.02, χ2 =0.034). Children with higher brushing frequency were more likely to use fluoridated dentifrice (P=.03, χ2 <0.001). The proportion of Australian pre-schoolers using non-fluoridated dentifrice was higher than in other world regions. Higher parental education level was strongly associated with choosing non-fluoridated toothpaste, which warrants further qualitative analysis to assess determinants for parents' choice of child dentifrice.

A randomised clinical evaluation of a fluoride mouthrinse and dentifrice in an in situ caries model

ObjectivesFluoride mouthrinses provide advantages for fluoride delivery by maintaining elevated intra-oral fluoride concentrations following fluoride dentifrice use. This in situ caries study investigated potential anti-caries efficacy of a 220 ppm fluoride mouthrinse. MethodsThis was an analyst-blinded, four-treatment, randomised, crossover study using partially demineralised, gauze-wrapped, human enamel samples mounted in a mandibular partial denture. Participants brushed twice daily for 14 days with either a 1150 ppm fluoride or a fluoride-free placebo dentifrice and either rinsed once daily with the 220 ppm fluoride mouthrinse or not. Following each treatment period, percent surface microhardness recovery (%SMHR) and enamel fluoride uptake (EFU) were assessed. ResultsFifty three participants completed the study. Compared with the placebo dentifrice/no rinse treatment, the fluoride-containing regimens demonstrated greater enamel remineralisation (%SMHR) and fluoridation (EFU): fluoride dentifrice/fluoride rinse (%SMHR difference: 21.55 [95% CI: 15.78,27.32]; EFU difference 8.35 [7.21,9.29]); fluoride dentifrice/no rinse: 19.48 [13.81,25.15]; 6.47 [5.35,7.60]; placebo dentifrice/fluoride rinse: 16.76 [11.06,22.45]; 5.87 [4.72,7.00] (all P < .0001). There were no significant differences in%SMHR between fluoride regimens. The fluoride dentifrice/fluoride rinse regimen was associated with higher EFU than the fluoride dentifrice/no rinse (1.88 [0.75,3.01], P = .0013) and placebo dentifrice/fluoride rinse regimens (2.48 [1.34,3.62], P < .0001). Treatments were generally well-tolerated. ConclusionsThe in situ caries model demonstrated that the fluoride mouthrinse is effective in promoting enamel caries lesion remineralisation and fluoridation whether used following a fluoride or non-fluoride dentifrice. Additive (potential) anti-caries benefits of a fluoride rinse after a fluoride dentifrice were confined to enhancements in lesion fluoridation (EFU). Clinical significanceIn conjunction with a fluoride dentifrice, fluoride mouthrinses enhance enamel fluoridation, which may be useful in caries prevention.

Dentifrice Containing Extract of Rosmarinus officinalis Linn.: An Antimicrobial Evaluation.

This study aimed to evaluate the antimicrobial activity of a dentifrice containing an alcoholic extract of rosemary on oral bacteria, compared to a commercially available herbal dentifrice. Standard strains of Streptococcus mutans (ATCC 25175), Streptococcus oralis (ATCC 9811) and Lactobacillus rhamnosus (ATCC 7469) were used, as well as different toothpastes based on rosemary (TR), on propolis (TH), triclosan (positive control) (TPC) and non-fluoridated dentifrice (negative control) (TNC). Bacteria were seeded in Petri dishes and paper discs soaked with dilutions of dentifrice placed on the plates. The inhibition halos were analyzed. It was observed that TR did not show statistical difference in relation to the TH to inhibit S. mutans and S. oralis, while TH was more active against L. rhamnosus. The toothpaste containing rosemary extract had the ability to inhibit the growth of S. mutans, S. oralis and L. rhamnosus, revealing an antimicrobial activity similar to commercially available toothpastes for inhibition of S. mutans and S. oralis.

The effect of CO2 laser irradiation plus fluoride dentifrice on the inhibition of secondary caries on root surfaces adjacent to glass ionomer cement or composite resin restorations

Although the cariostatic effects of CO2 laser on the root surface have been shown, there is scarce information regarding its effects on root secondary caries. The objective of this research was to investigate the effect of the association of CO2 laser and a fluoride dentifrice on the inhibition of secondary caries on root surfaces adjacent to composite-resin or glass-ionomer-cement restorations. Dental blocks of human roots were divided into two groups: composite resin (CR) or glass ionomer cement (GIC). Subsequently, the blocks were divided into four subgroups (n = 10): C, non-fluoride dentifrice; FD, fluoride dentifrice; L, CO2 laser with an energy density of 6.0 J cm−2 + non-fluoride dentifrice; and L + FD, CO2 laser + fluoride dentifrice. The blocks were subjected to pH cycling to simulate a high cariogenic challenge. Dental demineralization around the restorations was quantified by microhardness analysis. The results were subjected to analysis of variance (ANOVA) and the Tukey–Kramer test (p ⩽ 0.05). As for mineral loss, it can be observed that all the groups that were treated with a fluoride dentifrice and laser, used alone or not, were statistically similar and superior to the RC–C group. It was concluded that CO2 laser irradiation and a fluoride dentifrice used alone or combined with each other are efficient surface treatments for preventing secondary root caries, regardless of the restorative material used.

Comparative Analysis Of Remineralized Early Enamel Carious Lesions Subjected To Variable Concentrations Of Fluoride Supplement Through Polarized Light Microscope

Aim Comparative evaluation of the linear depth of induced remineralized lesions measured in microns after subjecting to fluoride supplements at both the demineralized and the remineralized zones in the three study groups under polarized light microscope. Method Forty five sound human premolars extracted for orthodontic reasons were decoronated 1 mm below the cemento-enamel junction and coated with nail varnish except for a 3 x 3 mm window on the buccal surface. The samples were placed in 50 ml of demineralizing solution at pH 4.6 for 96 hours. Following demineralization the lower half of the 3 x 3 mm window in all the samples were covered with nail varnish to serve as control. The samples were randomly divided into three groups of fifteen teeth each n15 and specimens in group A were remineralized using non-fluoridated dentifrice control those in group B and group C using 500ppm and 1000ppm of fluoride containing dentifrice respectively. The specimens were subjected to a 20 day remineralization treatment regimen and were sectioned into 100 mum thick sections and two images were captured on the buccal surface from either side of the midpoint of occluso-cervical length using polarized light microscope PLM.Results The values were tabulated and statistically analyzed by Anova. The highest values of linear depth for demineralization under PLM was seen in the group A non-fluoridated dentifrice control which was found to be 184.68plusmn6.43 mumTable 5 and the highest value for the remineralization was also seen in group A and was found to be 156.07plusmn4.76 mum which was significantly higher than that for the group C.Conclusion Study concluded that 1000 ppm fluoridated dentifrice showed a greater degree of remineralization than other groups and polarized light microscope gives promising results in the diagnosis of early enamel lesions over the conventional methods.

Development of caries adjacent to composite restorations after exposure to dentifrices with different fluoride concentrations

Objective To evaluate the development of recurrent caries after exposure to fluoride dentifrices with different concentrations. Material and method: 48 samples of bovine incisors (4x4mm2) were exposed to pH cycling for 7 days before the preparation of the cavities (2mm deep). The samples were restored with a microhybrid resin composite. Then, the samples were exposed to thermal cycling (350 cycles) and they were randomly allocated into 4 treatment groups (n = 12): Group A - non-fluoridated dentifrice (negative control); Group B - 500 ppm dentifrice; Group C - 750 ppm dentifrice; group D - 1100 ppm dentifrice (positive control). The samples were treated with solutions of each dentifrice (9.6 ml water/1.6 g dentifrice) for 60 seconds and then were immersed in demineralizing (3 h) and remineralizing (2 h) solutions 3 times a day. Next, the samples were immersed in a remineralizing solution for 18 hours. Then, the blocks were sectioned for examination of the length of the outer caries lesion, using polarized light microscopy. The ANOVA parametric test complemented by the Tukey test with a confidence level of 95%, were used in the statistical analysis. Result: A smaller lesion length was observed in the group treated with the fluoride concentration of 1100 ppm F, but there were no differences between toothpastes with fluoride concentrations of 500 and 750 ppm F. Conclusion: The use of fluoride dentifrices (1100 ppm) reduces the development of caries adjacent to dental restorations.

The effect of various oral hygiene products on the microbial flora in patients undergoing orthodontic treatment

Context Orthodontic devices lead to significantly greater plaque accumulation and gingival inflammation resulting in a change of gingival flora from cocci and rods to motile organisms like spirochetes. Aims The aim was to study the effect of various oral hygiene products on the microbial flora in patients undergoing orthodontic treatment. Materials and Methods The microbial composition of 40 patients, divided into four groups of 10 patients each, was evaluated. Group I patients were prescribed nonfluoridated dentifrice which act as the control group, Group II patients were given fluoridated dentifrice while in Group III and Group IV fluoridated mouth rinse and cetylpyridinium chloride mouth rinse, respectively, along with nonfluoridated toothpaste was prescribed. The plaque sample was collected at the start of orthodontic treatment, after 30 days, 60 days and 90 days for all the patients. The microscopic slides were prepared and observed under dark field microscopy at the magnification of ×1000 and microbes were classified as cocci, spirochetes, fusiforms, filaments, and rods. Results After applying analysis of variance and Tukey honest significant difference test, it was observed that after 30 days, only the proportion of filaments was found to be significantly higher in Group I. After 60 days, Group I had significantly lower proportion of cocci and a higher proportion of rods as compared to other groups. After 90 days, Group I had significantly higher count of rods, filaments, fusiforms, and spirochetes as compared to Groups III and IV. Conclusion Less amount of the microbial shift to the pathogenic organisms was seen in the patients in whom mouthwashes along with tooth brushing were prescribed.

Período de wash-out en diseños experimentales cruzados con dentífrico de alta concentración de fluoruro

ObjectiveMost crossover studies using fluoride dentifrice (FD) of standard concentration (1000-1500ppm F) have empirically used a wash-out period of 7 days to remove the residual effect of the treatment. For higher concentrations of FD (5000ppm F) the period is unknown, and a longer time may be required to remove fluoride (F) from saliva. Therefore, the aim of the study was to determine if less than 7 days of wash-out would be sufficient to remove residual F in saliva after using 5000ppm F FD. MethodologyAn in vivo study, blind analysis, was conducted on volunteers (n=6) who brushed their teeth 3 times per day in the following sequence: a) initial or lead-in period of 3 days using placebo fluoride dentifrice (PD) (0ppm F); b) using a high concentration FD (5000ppm F) for 4 days; and c) wash-out using PD for 3 days. During the 3 periods, samples of non-stimulated and stimulated saliva were collected after fasting (one overnight period from the last brushing). Fluoride concentration was assessed in saliva using a fluoride specific electrode. ResultsF concentrations in saliva after discontinued use of FD (wash-out period of 2 and 3 days) were similar to baseline values. F concentrations did not differ between unstimulated and stimulated saliva. ConclusionA two day wash-out period using non-fluoridated dentifrice was sufficient to eliminate residual F in saliva after use of a high concentration F dentifrice. These results are also valid for standard concentrations of dentifrice.

Comparative efficacy of dentifrice containing sodium monofluorophosphate + calcium glycerophosphate and non-fluoridated dentifrice: A randomized, double-blind, prospective study

Background:The efficacy of fluoridated dentifrices in caries prevention has been well documented and research into various formulations continues for a more effective dentifrice. This study evaluated the anti-caries and anti-plaque efficacy of a dentifrice containing sodium monofluorophosphate (1000 ppm) and calcium glycerophosphate, and compared it with a non-fluoridated dentifrice.Materials and Methods:A total of 595 school children (12–15 years) were divided into test (302 children) and control (293 children) groups. The test group used the dentifrice containing sodium monofluorophosphate (1000 ppm) and calcium glycerophosphate, whereas the control group was given a placebo dentifrice. Oral examination for dental caries and plaque assessment was carried out at the start of the study and the children were followed up semiannually up to 18 months. Data were analyzed using repeated-measure analysis of variance (ANOVA) followed by one-way ANOVA.Results:The values for decayed missing filled teeth (DMFT) increased from baseline to 18 month examination from 4.43±2.03 and 4.67±2.25 (P=0.175) to 5.84±2.29 and 5.13±2.30 (P=0.001) for control and test groups, respectively. Similarly, the increase in decayed missing filled surface (DMFS) values were from 6.42±4.10 and 7.06±4.77 (P=0.082) to 8.64±4.51 and 7.92±5.07 (P=0.095) for test and control groups, respectively. The mean DMFT and DMFS values increased for both the groups; however, the increase was less in test group as compared to control group. The baseline plaque score reduced from 2.94±0.72 and 2.91±0.72 (P=0.679), respectively, for control and test groups to 1.33±0.46 and 0.91±0.38 (P<0.001), respectively, at 18 month examination.Conclusion:Results revealed that the test dentifrice was effective in inhibiting the progression of plaque and control of dental caries as compared to the placebo dentifrice.

Does a chitosan-containing dentifrice prevent demineralization around orthodontic brackets?

To test the null hypothesis that there is no significant difference between the chitosan-containing and conventional nonfluoridated dentifrices in inhibition of enamel demineralization around orthodontic brackets. Sixteen orthodontic patients who were scheduled to have extraction of four first premolars for orthodontic reasons were divided into two groups after the power of the study was estimated. Patients in the experimental group were instructed to use chitosan-containing dentifrice (AloeDent), and patients in the control group were instructed to use nonfluoridated dentifrice (Sensodyne Mint). After 60 days, the teeth were extracted and longitudinally sectioned. The demineralization was assessed by cross-sectional microhardness. The determinations were made at the bracket edge cementing limits and at occlusal and cervical points, 100 µm and 200 µm away from the edge. In all these positions, indentations were made at depths of 10, 20, 30, 50, 70, and 90 µm from the enamel surface. Analysis of variance (ANOVA) and Tukey test were used for statistical evaluation at P < .05 level. ANOVA showed statistically significant differences for the factors of dentifrice type, position, and depth (P = .000). Statistically significant differences for microhardness values between two tested dentifrices were observed up to 20 µm of depth from the enamel surface (P < .05). Lower microhardness values were found for nonfluoridated dentifrice. Significant microhardness differences were also determined between materials at occlusal and cervical 0 µm positions (P < .05). At these positions, chitosan-containing dentifrice showed lower demineralization than the control. Chitosan-containing dentifrice may reduce the enamel decalcification found in patients with poor oral hygiene. The null hypothesis is rejected.

Qualitative analysis of re mineralized carious lesions subjected to fluoride supplement through confocal laser scanning microscope

Aim: 1] Comparative evaluation of the linear depth of induced remineralized lesions after subjecting to fluoride supplements and 2] To assess the average fluorescence at both the demineralized and the remi-neralized zones in all the three study groups under confocal laser scanning microscope. Method: Forty five sound human premolars extracted for orthodon-tic reasons were decoronated 1 mm below the ce-mento-enamel junction and coated with nail varnish except for a 3 × 3 mm window on the buccal surface. The samples were placed in 50 ml of de mineralizing solution at pH 4.6 for 96 hours. Following deminera-lization, the lower half of the 3 × 3 mm window in all the samples were covered with nail varnish to serve as control. The samples were randomly divided into three groups of fifteen teeth each (n = 15) and speci-mens in group A[Nfd] were remineralized using non-fluoridated dentifrice [control], those in groups B [Fd5] and group C [Fd10] using 500 ppm and 1000 ppm of fluoride containing dentifrice, respectively. The specimens were subjected to a 20 day reminera-lization treatment regimen and were sectioned into 100 µm thick sections and two images were captured on the buccal surface from either side of the midpoint of occluso-cervical length using confocal laser scan-ning microscope [CLSM]. Results: were tabulated and statistically analyzed by Anova. Study concluded that 1000 ppm fluoridated dentifrice showed a greater degree of remineralization than other groups and confocal laser scanning microscopes gives promising results in the diagnosis of early enamel lesions over the conventional methods.

Comparison of the remineralizing potential of child formula dentifrices

Although child formula fluoridated dentifrices can be used safely by young children their remineralizing capability remains questionable. To evaluate the remineralizing potential of child formula dentifrices on primary teeth. In vitro single-section technique utilizing a 7 days pH-cycling model. Primary teeth were placed in demineralizing solution for 96 h to produce artificial carious lesions 100 μm deep, and then cut longitudinally into 50 sections 100-150 μm thick and randomly assigned to five groups. Sections in Groups A to D were treated with dentifrices containing 500 ppm AmF, 500 ppm MFP, 500 ppm MFP and xylitol, or 500 ppm NaF, respectively. Group E sections were treated with a nonfluoridated dentifrice. Lesions were evaluated using polarized light microscopy and microradiography. Group D (500 ppm NaF) sections exhibited a significant decrease in lesion depth, whereas those in Group E (nonF) showed a significant increase in depth (P<0.05, paired t-test). Decrease in lesion progression was observed in Groups A, B and C. The 500 ppm NaF dentifrice demonstrated remineralization of carious lesions by virtue of a significant decrease in lesion depth; whereas dentifrices that contained AmF, MFP and MFP with xylitol decelerated the progression of demineralization.

In vivo remineralization of artificial enamel carious lesions using a mineral-enriched mouthrinse and a fluoride dentifrice: A polarized light microscopic comparative evaluation

Remineralization process is accelerated by the presence of fluoride ions in the oral environment, but this mechanism of caries reversal will be further enhanced if the concentration of calcium, phosphate and fluoride ions is supersaturated with respect to that of oral fluids. This in vivo study was carried out to evaluate and compare the remineralizing efficacy of a urea-based mineral-enriched mouthrinse and a fluoridated dentifrice using an in vivo intraoral appliance model and polarized light microscopic evaluation technique. The specimens were prepared from sound teeth and artificial caries was produced using an artificial caries medium in vitro and enamel specimens were inserted in removable orthodontic appliances that were to be worn by 14 children of 10-15 years of age. They were divided into three groups - nonfluoridated dentifrice, fluoridated dentifrice and mineral-enriched mouthrinse groups. After the 6-month experimental period, during which the enamel specimens inserted in the intraoral appliance were subjected to one of the agents (either fluoride, nonfluoride dentifrice or mouthrinse) in vivo, the specimens were retrieved from the patients and were evaluated using the polarized light microscopic technique. On analysis, mineral gain occurred in all groups, viz. nonfluoride dentifrice group, fluoride dentifrice and mineral-enriched mouthrinse group. However, it was found to be complete in the mouthrinse group, i.e. both at the surface and at the subsurface (67%), while in the fluoridated dentifrice group, 43% of the samples showed mineral gain in both zones. In the nonfluoridated dentifrice group also, remineralization occurred but was limited either to the surface or the subsurface zone. Urea-based mineral-enriched mouthrinse was shown to be more efficacious in the process of remineralization of artificial carious lesions.

Effect of Glass Ionomer Cement and Fluoride Varnish on the Remineralization of Artificial Proximal Caries in Situ.

To compare the effect of glass ionomer cement (GIC) and fluoride varnish (F-varnish) on artificial proximal caries in situ. Two 1 x 3 mm2 enamel slabs, divided into three 1 x 1 mm2 windows, were prepared from each proximal surface of 18 premolars. Each slab was distributed into a control area, an intact enamel area and a test area. Artificial lesions were created on the control and test areas by immersing in demineralizing solution for 24 hours. The test windows were either applied with GIC or F-varnish and the full slabs inserted into orthodontic brackets as carriers, which were then bonded to the buccal surfaces of the 6 upper posterior teeth of 6 volunteers using non-fluoride dentifrice for 30 days. There was a 1-week washout period in this crossover study. The middle specimens of the three windows were cross-sectioned to analyze the carious lesion area by a polarized light microscope and calculated with Image-Pro plus software. The average carious lesion area under GIC was significantly less than that under F-varnish (p < 0.05). GIC promotes more remineralization of artificial carious lesions on proximal surfaces than F-varnish.

The Effects of Three Different Pastes on Enamel Caries Formation and Lesion Depth Progression-An In Vitro Study

ABSTRACT Prevention of initiation and interruption in progression of early lesions are the desirable modes of caries management. Fluoride dentifrices and casein phosphopeptides are known to inhibit demineralization and enhance remineralization. The present study was conducted with the objective to investigate the effects of fluoridated dentifrice, non-fluoridated dentifrice and casein phosphopeptide amorphous calcium phosphate paste on enamel caries formation and lesion depth progression.228 tooth sections derived from extracted human permanent molars.were used The study was carried out in 3 phases where in each phase the enamel sections were treated for 14 days twice a day for 3 minutes with respective agents, followed by acid demineralization using 0.05 M acetic acid resulting in lesions. The depths of the lesions were measured using stereomicroscope. The mean lesion depths of three test groups were compared with each other as well as with control group at the end of each phase. Comparison of mean lesion depths of different groups was carried out using analysis of variance (ANOVA) and student's unpaired-t-test. The fluoridated dentifrice group had significantly lesser mean lesion depth than control group in all the three phases (P&lt;0.05). In second phase, non-fluoridated dentifrice and CPP-ACP paste groups had significantly lesser mean lesion depths than control groups (P&lt;0.05). The study demonstrated that twice a day application of fluoridated dentifrice provides substantial protective effect against lesion formation and lesion depth progression. The study could not demonstrate any additional ability of CPP-ACP paste in reducing lesions depth progression and effect was similar to non-fluoridated dentifrice group.

In situ effect of a dentifrice with low fluoride concentration and low pH on enamel remineralization and fluoride uptake

Since the anticaries effect of a dentifrice with low fluoride concentration and low pH is unknown, the aim of the present study was to evaluate in situ the enamel remineralizing ability of this type of formulation. A double-blind crossover design employing 3 phases of 45 days was conducted. Six adult volunteers wore palatal devices containing 6 previously demineralized human dental enamel slabs, which were subjected 3 times a day to one of the following treatments: non-fluoridated dentifrice (negative control); dentifrice containing 1, 100 microg F/g, pH 7.0 (positive control); dentifrice containing 550 microg F/g, pH 5.5 (experimental). At the end of each phase, enamel remineralization was assessed in terms of cross-sectional microhardness, and loosely as well as firmly bound fluoride formation was determined on the enamel surface. Fluoridated dentifrices were more effective than the negative control in forming loosely and firmly bound fluoride on enamel (P < 0.05). However, the positive control formed more loosely bound fluoride than the other treatments (P < 0.05). Microhardness analysis showed that the fluoridated dentifrices were more effective than the negative control (P < 0.05) in remineralizing dental enamel, although no statistically significant difference was observed between them. Thus, the experimental dentifrice was shown to be effective in remineralizing dental enamel, and this may be attributable to its ability to form firmly bound fluoride on enamel.

In situ Mineral Loss Inhibition by CO2 Laser and Fluoride

Laser and fluoride treatments have been shown to inhibit enamel demineralization in the laboratory. However, the intra-oral effects of this association have not been tested. This study assessed in situ the effect of a Transversely Excited Atmospheric CO2 laser (lambda = 9.6 mum) and the use of pressure fluoridated dentifrice on enamel demineralization. During two 14-day phases, 17 volunteers wore palatal appliances containing human enamel slabs assigned to treatment groups, as follows: (1) non-fluoride dentifrice, (2) CO2 laser irradiation plus non-fluoride dentifrice, (3) fluoride dentifrice, and (4) CO2 laser irradiation plus fluoride dentifrice. A 20% sucrose solution was dripped onto the slabs 8 times per day. The specimens treated with laser and/or fluoridated dentifrice presented a significantly lower mineral loss when compared with those from the non-fluoride dentifrice group. The results suggested that CO2 laser treatment of enamel inhibits demineralization in the human mouth, being more effective when associated with fluoride.

Acid Susceptibility of Arrested Enamel Lesions: In situ Study

Arrested lesions are more resistant to a new cariogenic challenge, but the degree of surface rehardening needed to achieve this is unknown. The aim of this in situ study was to analyze the acid susceptibilityof newly formed and arrested enamel lesions with known arrestment period and surface microhardness. Six individuals wore an oral appliance with human enamel blocks for 3 periods: (1) 21 days of demineralization due to plaque accumulation and cariogenic challenge, 4 blocks/person (nonfluoride dentifrice); (2) 75 days of arrestment, brushing with fluoride dentifrice, 2 blocks/person; (3) 21 days of demineralization, 5 blocks/person: 1 sound block, 2 demineralized blocks and 2 demineralized and arrested blocks (nonfluoride dentifrice). After period 1, all blocks showed a dull whitish surface characteristic of active, noncavitated lesions. After arrestment, the surfaces assumed a shiny and smooth aspect. The Knoop hardness number (KHN, mean ± SD) of the sound blocks was 307.6 ± 15.0. After period 1, microhardness decreased significantly to 162.6 ± 33.5 KHN (p < 0.001). The microhardness of subsequently arrested lesions (279.8 ± 23.1 KHN) was significantly greater than after demineralization, but lower than that of sound enamel. Arrested enamel did not show a decrease in microhardness when subjected to a new cariogenic challenge and after the same cariogenic challenge showed similar microhardness to sound enamel. The results showed that, although noncavitated lesions probably take years to reach microhardness levels like sound enamel, this does not imply that special care, in addition to the ones normally given to sound tooth surfaces, is necessary.

Effect of iron on bovine enamel and on the composition of the dental biofilm formed “in situ”

This study investigated in situ the effect of iron (Fe) on the reduction of demineralization of bovine enamel, as well as on the composition of dental biofilm. Twelve volunteers were included in this blind crossover study, which was conducted in two stages of 14 days each. For each stage, the volunteers received palatal appliances containing four blocks of bovine enamel (4 mm x4 mm x 2.5 mm). Six volunteers dripped a solution of 15 mmol L(-1) ferrous sulphate onto the fragments and the remaining six dripped deionized water (eight times per day). After five minutes, a fresh 20% (w/v) sucrose solution was dripped onto all enamel blocks. During the experimental period the volunteers brushed their teeth with non-fluoridated dentifrice. After each stage, the percentage of surface microhardness change (%SMHC) and area of mineral loss (DeltaZ) were determined on enamel and the dental biofilm formed on the blocks was collected and analysed for F, P, Ca, Fe and alkali-soluble carbohydrates. The concentrations of F, Ca and Fe in enamel were also analysed after acid biopsies. There was a statistically significant increase in the P and Fe concentrations in the biofilms treated with ferrous sulphate (p<0.05), which was not observed for F, Ca and alkali-soluble carbohydrates. The group treated with ferrous sulphate had significantly lower %SMHC and DeltaZ when compared to control (p<0.05). These results showed that ferrous sulphate reduced the demineralization of enamel blocks and altered the ionic composition of the dental biofilm formed in situ.