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PubMed2005

Remineralization of carious dentin. II: In vivo microradiographic and chemical studies in human permanent teeth capped with calcium hydroxide.

The main aim of this in vivo study was to evaluate a possible remineralization of human carious dentin by means of chemical and microradiographic studies. Eighty-six samples of carious dentin were removed from 36 permanent teeth of 24 patients. These were divided into untreated (control) and chemically pure calcium hydroxide-capped (experimental) samples and analyzed at intervals varying from 10 to 120 days. They were classified according to depth of caries and degree of dentin softening and evaluated in relation to weight, phosphorus concentration, qualitative and quantitative microradiography and absolute values of total mineral content. One of two halves of each sample was selected for chemical studies and the other for total content of mineral salts. Experimental samples were examined with a light microscope and the results obtained showed a qualitative increase in radiopacity. Quantitatively, it was observed that, in the case of samples analyzed for phosphorus concentration, the average mean of differences in percentage increase after treatment was 9.6%, while for the samples evaluated microradiographically for total mineral content, it was 22.29%. In both cases, the differences were statistically significant.

Adolescent↗

PubMed1991

Acid-etched enamel surfaces after 24 h exposure to calcifying media in vitro and in vivo.

The remineralization of acid-etched enamel lesions is investigated in this study both in vitro and in vivo over periods of 24 h. In an initial study, samples of etched bovine enamel were subjected in vitro to treatment with synthetic calcifying solutions, or were exposed to saliva by means of an intraoral appliance. Alterations in hardness of the enamel surface were measured by indentation techniques. In a second study the suitability of an impression technique for investigating the surface relief induced by an acid-etch procedure was investigated. Extracted human incisors were used to make SEM observations of eteched areas and corresponding sections of impressions. Subsequently, six subjects were selected for a clinical evaluation of the impression technique. Although a significant decrease in indentation length (increase in hardness) was observed for etched enamel lesions treated with calcifying solutions in vitro, no evidence for any such change was observed in samples exposed to the influence of saliva when investigated by the indentation and impression techniques.

Acid Etching, Dental↗

PubMed1990

Prevention of enamel demineralization adjacent to glass ionomer filling materials.

In order to study the release of fluoride and prevention of enamel demineralization by different filling materials, standardized cavities were prepared in 80 extracted human molars. The cavities were filled as follows: 1. Fuji II F; 2. Ketac-Fil; 3. Ketac-Silver; 4. Silar. Twenty molars were used as controls (no filling). Enamel slabs with the fillings were subjected to 9 days of demineralization (30 min daily) and remineralization (artificial saliva, replaced daily). Fluoride release in the saliva was determined on days 1, 3, 5, and 9. Enamel fluoride content adjacent to the cavities was determined initially and after the de-remineralization using the acid etch technique. On day 1, the largest amount of fluoride in the saliva was released by Fuji, but on day 9 the largest amount was released by Ketac-Fil. Ketac-Silver released significantly less fluoride than Fuji and Ketac-Fil. The average initial fluoride content of enamel was 2200 ppm. After the test period, fluoride contents adjusted for biopsy depth were 1822, 1690, 1693, 1337, and 888 ppm in groups 1-5, respectively. The amounts of phosphorus dissolved by the second acid etch were 28.9 (SE 2.6), 30.2 (2.0), 34.4 (2.8), 44.1 (2.7), and 42.2 (2.4) micrograms, respectively. Softening of surface enamel during the test period was clearly reduced in teeth filled with Fuji and Ketac-Fil. The results show that glass ionomer materials release considerable amounts of fluoride and prevent demineralization of the adjacent enamel in vitro. Fuji and Ketac-Fil seem to be more effective than Ketac-Silver.

Acrylic Resins↗

PubMed1991

Demineralization of human dentine compared with enamel in a pH-cycling apparatus with a constant composition during de- and remineralization periods.

A comparison was made between the demineralization of enamel and dentine with and without abraded surfaces. This was done in a pH-cycling experiment for different demineralization/remineralization ratios--in the range from 1:1 to 1:4--and for different fluoride additions (up to 2 ppm) in solution. A new automatic pH-cycling system, in which the de- and remineralization solutions have a constant composition during the de- and remineralization cycles, was used to create mineral loss in human dentine and enamel. Changes in mineral content were monitored by means of longitudinal microradiography. A linear correlation was found between the amount of mineral lost and the total demineralization time for both dentine and enamel. The demineralization rates were comparable for abraded enamel and dentine and for polished enamel and dentine, and this rate was roughly doubled by the removal of the outer surface for both tissues. This showed that the presence of the outer surface is equally important to dentine and enamel. Under the pH-cycling conditions used, a logarithmic relation was found between the addition of fluoride and the decrease in demineralization for both enamel and dentine. The inhibitory effect of fluoride on demineralization was most pronounced on abraded enamel, followed by pumice-polished enamel, abraded dentine and pumice-polished dentine. About 2 ppm fluoride was needed under the conditions used to stop enamel demineralization completely; in the case of dentine, however, this amount of added fluoride did not inhibit demineralization.

Analysis of Variance↗

PubMedDate not supplied

In situ evaluation of sodium hexametaphosphate-containing dentifrices.

The purpose of this investigator-blinded, five-treatment, crossover human intraoral study was to evaluate the effects of two experimental dentifrice formulations containing either stannous fluoride (SnF(2)) or sodium fluoride (NaF) packaged with sodium hexametaphosphate in a dual-phase delivery system on demineralization-remineralization using an in situ model system. The experimental dentifrice formulations' ability to alter demineralization-remineralization was compared to a series of three controls: SnF(2)-positive control, NaF-positive control and no-fluoride placebo-negative control. The single-section crown model, developed at the University of Iowa, was used to assess the fluoride efficacy of two experimental products versus the placebo containing no fluoride and positive controls. The results of the current in situ study suggest a clinical level of anticaries activity for the experimental SnF(2) and NaF dentifrice formulations that was as good as either of the positive controls, when evaluated using polarized light microscopy. This supports the conclusion that the use of the sodium hexametaphosphate ingredient does not interfere with the normal fluoride activity of these toothpastes. In addition, the experimental SnF(2) product was numerically better than both the NaF and placebo controls at preventing demineralization of sound root surfaces.

Adult↗

PubMed1998

Studies on fluoridated toothpicks.

The aim of this thesis was to evaluate the wooden toothpick as a vehicle for the delivery of fluoride to the approximal area. After two minutes use in vivo, the release of fluoride from the pointed section of a toothpick impregnated in 4% NaF was estimated to 0.15 mg. Toothpicks produced similar or somewhat higher fluoride concentrations in the approximal area compared with other fluoride-containing products, like dentifrice, mouthrinse solution and tablet. The mean fluoride concentration in an approximal area treated for two minutes with a toothpick impregnated in 4% NaF was around 11 mM/l. Toothpicks impregnated in 4% NaF, 8% SnF2 or 2% chlorhexidine had an effect on the proportion of mutans streptococci and on the decline of pH in dental plaque, but it was small and only of short duration. The recolonization of mutans streptococci was, however, slower after using the SnF2- and chlorhexidine-impregnated toothpicks than after using the NaF- and non-impregnated toothpicks. The effect of fluoridated toothpicks on the degree of de- and remineralization of enamel and dentine was measured using transversal microradiography in an in situ study. Four weeks' use of toothpicks, especially of NaF-impregnated toothpicks, reduced the degree of demineralization of enamel and dentine at approximal sites. Secondary ion mass spectrometry was also used to determine the fluoride content in the outer surface of dentine, which increased more than 10 times after using fluoride toothpicks compared with non-impregnated toothpicks. In a second in situ study, 4% NaF-, 2% chlorhexidine- and non-impregnated toothpicks had a similar effect on sound and demineralized enamel and on demineralized dentine. However, the NaF toothpicks were superior in terms of their effect on sound dentine. The effect on mutans streptococci and plaque-pH, on the other hand, was the same for all three types of toothpicks. The main conclusion from this thesis is that the wooden toothpick is a suitable vehicle for the delivery of fluoride to the approximal area.

Anti-Infective Agents, Local↗

PubMed2006

Hardness of enamel exposed to Coca-Cola and artificial saliva.

The purpose of this study was to determine the rate of change in indentation hardness of enamel in permanent teeth exposed to Coca-Cola. In a further experiment, the ability of a commercially available artificial saliva to remineralize enamel treated with Coca-Cola was tested. Ten enamel specimens were randomly chosen to be treated with Coca-Cola (experimental groups) and seven with water (control group). The fluids were applied for 1, 2, 3 h and overnight (15 h), washed off with a few drops of water and the moist enamel indentation hardness tested after each interval. With Coca-Cola treatment, the mean enamel hardness was 92.6% (s.d. = 7.9) of the original baseline hardness after 1 h, 93.25% (s.d. = 10.15) after 2 h, 85.7% (s.d. = 12.03) after 3 h and 80.3% after 15 h. The mean indentation hardness of control specimens treated with water was 108.7% (s.d. = 16.09) of the original hardness after 1 h, 99.09% (s.d. = 18.98) after 2 h, 98.97% (s.d. =11.24) after 3 h and 98.42% (s.d. = 22.78) after 15 h. In a separate experiment, the hardness of 9 enamel specimens was tested, as previously described, before and after treatment with Coca-Cola overnight and again after application of artificial saliva for 3 min. Coca-Cola reduced the mean indentation hardness of enamel in the teeth, but the hardness was partially restored with artificial saliva (Salivart) and increased by 18% from the demineralized enamel hardness.

Carbonated Beverages↗

PubMedDate not supplied

Effect of a low-fluoride-content, two-component rinse on fluoride uptake and on de--and remineralization of enamel lesions: an in vitro study.

The effect of calcium (Ca) concentrations and added ethanol on fluoride (F) depositions by experimental two-component rinses, each consisting of a Ca-containing and an F-containing component, was evaluated in an in vitro system. Among the tested rinses, a 3 mmol/l F two-component rinse with 200 mmol/l Ca and 10% v/v ethanol was found to produce the greatest F deposition relative to the F concentration in the rinse. Specifically, this rinse produced an F deposition that was about 7 times greater than a conventional 13.2-mmol/l sodium fluoride (NaF) rinse. In a second experiment, an in vitro pH cycling model was used to evaluate the potential anti-caries effects of 4 rinses: (1) placebo rinse (no F), (2) 13.2-mmol/l NaF rinse, (3) 52.6-mmol/l NaF rinse, and (4) the 3-mmol/l F two-component rinse in a 7-day in vitro pH cycling model. The changes in lesion mineral contents, delta(DeltaZ), as assessed by quantitative microradiographic measurements, were as follows [mean +/- standard deviation, n = 10]: (1) 72.5+/-10.2 microm, (2) 43.4+/-5.6 microm, (3) 17.3+/-10.2 microm and (4) 45.3+/-5.2 microm. These results showed that the 3-mmol/l F two-component rinse produced the same (p>0.05) protection against demineralization as did the 13.2-mmol/l NaF rinse which had 4 times the fluoride content. The results suggest that it is possible to formulate an effective low-F two-component rinse.

Analysis of Variance↗

PubMed1992

Comparison of laser fluorescence and longitudinal microradiography for quantitative assessment of in vitro enamel caries.

A new quantitative, non-destructive method using laser-induced fluorescence (LAF) was compared with longitudinal microradiography (LMR) for assessment of mineral changes in enamel slices using an in vitro caries model. Ten enamel slices, cut longitudinally from sound natural smooth surfaces of human teeth, were exposed to de- and remineralization in a pH-cycling model. The enamel slices were subjected to LAF and LMR measurements before and at 2, 4, 7, and 9 days of demineralization. For LAF, the average fluorescence radiance decreased during the demineralization period with 11% by day 2 and 49% by day 9. For LMR, the corresponding average loss of mineral content changed with 0.01 and 0.10 kg.m-2 over the same time period. The mineral losses in each individual enamel slice measured with the two techniques were strongly correlated, r = 0.97. The Spearman rank correlation coefficient for all LAF and LMR demineralization results was 0.86. The precision (coefficient of variation) for LAF was 3.1%, corresponding to 0.005 kg.m-2, and the repeatability error for LMR was 0.02 kg.m-2, indicating a lower discrimination threshold for LAF compared to LMR. It was concluded that the new, sensitive, non-destructive LAF method provides possibilities for further improvement in the quantification of initial caries lesions in natural smooth enamel surfaces for use in in vitro studies. Furthermore, it offers potential in in situ caries studies as well as a tool in the diagnosis of early enamel caries in vivo.

Contrast Media↗

PubMed1990

A comparison of the influence of lanthanum and fluoride on de- and remineralization of bovine enamel in vitro.

The influence of fluoride and lanthanum on enamel softening was compared by hardness measurements and by determination of the calcium content in the solution. The addition of lanthanum to an acetate buffer solution (0.05 mol/L, pH = 5.0) had no significant influence on the change of the indentation length and on the calcium release, compared with those of the control group. In the fluoride group, a moderate increase of the indentation length and a reduced calcium loss were observed. In a second experiment, surface-softened bovine enamel was treated with calcifying solutions (Ca/P ratio = 1.67). Differences in treatment were created by the addition of traces (2 ppm) of lanthanum, fluoride, or both. The acid resistance of the treated enamel was evaluated by two successive softening steps (0.1 mol/L acetate buffer, pH = 5.5). Alterations of the enamel surface were longitudinally followed with a hardness tester. The addition of fluoride, lanthanum, or both significantly improved the rehardening of surface-softened enamel, compared with that of the control group. A 2 x 2 factorial analysis of variance showed that lanthanum and fluoride had a highly significant main effect and a significant negative interaction effect on the rehardening of surface-softened enamel. Subsequent acid treatments revealed that only samples treated with a fluoride-containing solution were adequately protected from further dissolution. The enamel surfaces treated with a solution containing both lanthanum and fluoride were covered with an acid-resistant surface coating. SEM observation of this surface layer revealed the presence of globular and spherulite structures.

Analysis of Variance↗

PubMed1999

Influence of acidified fluoride gel on abrasion resistance of eroded enamel.

The objective of the study was to evaluate the abrasion resistance of eroded enamel brushed with an acidified fluoride gel. Each enamel specimen was prepared from one of 64 bovine incisors. The specimens were embedded in acrylic resin, ground flat, polished and subsequently covered with a tape exposing an area of 1.8x10.0 mm in the center of the enamel specimens. The samples were alternatingly stored in a demineralizing solution (5 min) and a remineralizing solution (1min) four times. An acidic soft drink (Sprite Light(R)) served as a demineralizing solution and artificial saliva was used as a remineralizing solution. After each remineralization the specimens were brushed in an automatic brushing machine (2,000 strokes, 2.5 N load) and subsequently stored again in saliva (1 min). A mixture of artificial saliva (5 ml) with a gel (1 ml) based on the formulation of Elmex(R) gelée (Wybert, Lörrach, Germany) served as an abrasive slurry. Thirty seconds after brushing, the slurry was removed from the specimens by rinsing with destilled water. For each of 16 specimens the following gels (A-D) were used: gels A (pH 7.0) and B (pH 4.5) were unfluoridated; gels C (pH 7.0) and D (Elmex gelée; pH 4.5) contained 1.25% F-. After two cycles the specimens were kept in the saliva for 8 h. Finally the tape was removed and the abrasion was determined profilometrically. The following values (mean +/- SD) were obtained and statistically analyzed by analysis of variance and Wilcoxon two-sample tests (p</=0.01): gel A, 0.96+/-0.24 microm; B, 1.58+/-0.32 microm; C, 0. 71+/-0.23 microm; D, 0.25+/-0.08 microm. The differences between all experimental groups were statistically significant. It is assumed that treatment of enamel erosions with an acidified fluoride gel results in a higher abrasion resistance compared to gels which are either unfluoridated or neutral.

Amines↗

PubMed1987

Demineralization and remineralization around orthodontic appliances: an in vivo study.

The presence of clinically detectable areas of decalcification (observable as whitened areas) following the removal of orthodontic appliances is well recognized. The aim of the present study was to determine quantitatively the amount of demineralization and the ability of commercially available products to inhibit or reverse orthodontically related demineralization. Twenty orthodontic patients scheduled to have premolars extracted were randomly divided into four groups--one control and three test groups. The extracted premolars (numbering 58) were bracketed using an acid-etch composite system; each patient was given precise oral hygiene instructions and supplied with a sodium fluoride (1,100 ppm fluoride) dentifrice and an orthodontic toothbrush. The control group brushed only with the supplied dentifrice. In addition to brushing with the dentifrice, those in test group I rinsed once each night with a sodium fluoride (0.05%) mouthrinse; group II received a weekly topical APF treatment (1.2% fluoride); and Group III received a weekly topical APF treatment and rinsed once each night with the sodium fluoride mouthrinse. All premolars were extracted after 1 calendar month. Mineral profiles were determined on cross-sectioned teeth 50 to 75 micron occlusal and cervical to the brackets, directly underneath the brackets, and 500 micron away from the brackets. The control teeth (dentifrice only) demonstrated up to 15% demineralization to a depth of 50 micron. All of the test teeth produced rehardening and/or inhibition of demineralization (P less than 0.01). Those in test group III showed a particularly hard outer layer. The study demonstrated that measurable demineralization occurred around orthodontic appliances after only 1 month and this demineralization can be completely inhibited and/or reversed by the use of commercially available fluoride products.

Dental Bonding↗

PubMed2006

Influence of rotating-oscillating, sonic and ultrasonic action of power toothbrushes on abrasion of sound and eroded dentine.

OBJECTIVE: This in vitro study aimed to evaluate the susceptibility of sound and eroded dentine to brushing abrasion performed by different rotating-oscillating, sonic and ultrasonic toothbrushes. METHODS: Toothbrushing abrasion (20 cycles, each 30 s) was applied to bovine dentine samples (each subgroup n = 10) exhibiting both a demineralized (each cycle: 1% citric acid, pH: 2.3, 60 s; 30 min remineralization in artificial saliva) and a sound surface area. Toothbrushing was performed in an automatic brushing machine with the rotating-oscillating, sonic and ultrasonic toothbrushes either (a) activated, supplemented by 20 strokes/min of the brushing machine, (b) inactivated, supplemented by 20 strokes/min of the brushing machine or (c) inactivated, supplemented by 80 strokes/min of the brushing machine. A manual toothbrush was applied with 20, 80 or 100 linear strokes/min. Specimens of the control group were not brushed after erosion. After each cycle, the samples were stored in artificial saliva for 4 h. After 20 cycles, loss of sound and softened dentine was determined by profilometry. Mann-Whitney-Wilcoxon test and Bonferroni corrections were applied to the data (p < 0.05). RESULTS: For all groups, demineralized dentin areas exhibited significantly higher abrasion values than the respective sound dentine surfaces. However, mean dentine loss of both softened and sound dentine was higher after use of the rotating-oscillating, sonic and ultrasonic brushes with the activated regime [(a) eroded dentine: 9.94-16.45 microm; sound dentine: 3.31-5.47 microm] than after brushing with the inactivated regimes [(b) eroded dentine: 5.10-5.62 microm; sound dentine: 1.16-1.81 microm; (c) eroded dentin: 7.64-8.89 microm; sound dentine: 1.38-1.69 microm]. CONCLUSION: The results indicate that rotating-oscillating, sonic or ultrasonic action of the power toothbrushes leads to an increased loss of demineralized and sound dentine.

Animals↗

PubMedDate not supplied

Susceptibility of enamel surfaces to demineralization after application of fluoridated carbamide peroxide gels.

The aim of the present study was to evaluate the effect of experimental, fluoridated carbamide peroxide gels on formation of erosively induced demineralization of enamel. Seventy-five bovine enamel specimens were polished for microhardness determination and evenly distributed among 5 groups (A-E). The specimens were treated with 10% carbamide peroxide gel (8 h) and subjected twice to remineralization for 2 h in artificial saliva and demineralisation for 90 s in 1% citric acid, pH 2.2. The cycles of treatment with carbamide peroxide and twofold re- and demineralization were repeated three times. The carbamide peroxide gels were different in pH and fluoride content. Gel A (pH 7.0) and gel B (pH 5.7) were fluoridated (0.5% F), gel C (pH 7.0) and gel D (pH 5.7) were not fluoridated. In control group E the samples were not treated with a gel, but stored in 100% humidity for 8 h instead. Knoop microhardness of the specimens was assessed directly after polishing, and after each carbamide peroxide treatment and demineralization. All specimens showed a loss of microhardness at the end of the experiment. After 3 days, the controls revealed a significantly lower hardness loss compared to the specimens treated with the carbamide peroxide gels. Surface softening was significantly lower for the specimens of group A compared to the remaining groups (B-D), which were not significantly different among each other. It is concluded that treatment with either fluoridated or unfluoridated carbamide peroxide gels, at either neutral and acidic pH, renders enamel more susceptible to demineralization. Use of a fluoridated neutral gel decreases the degree of surface softening compared to the other gels investigated.

Analysis of Variance↗

PubMed2000

Caries preventive knowledge and practices among dental hygienists.

PURPOSE: The aim of this study was to determine the knowledge, opinions, and practices of dental hygienists in the areas of dental caries etiology and prevention. METHODS: A pretested, validated 35-question survey instrument was mailed to a one percent national, stratified random sample of dental hygienists in the United States (n = 960) in October 1996. Four complete mailings of the instrument resulted in a 67% response rate, of which 77% were useable (n = 498). Respondents were asked if they agreed or disagreed with statements on caries etiology and preventive procedures, and also asked to rate the effectiveness of procedures for preventing dental caries in children and adults. Data were analyzed using descriptive statistics, t-tests, and ANOVA. RESULTS: Overall level of knowledge of caries etiology and preventive procedures was low. More than 40% of subjects did not recognize that remineralization is the most important mechanism of action of fluoride, and fewer than 50% recognized that dental caries is a chronic infectious disease. Analysis of four factors thought to be related to knowledge and practice showed that younger graduates, more recent graduates, and ADHA members were more knowledgeable about the effectiveness of caries preventive procedures for children (p < .01). Although an overwhelming majority correctly agreed that adults benefit from fluoride and that root caries is an emerging problem, this knowledge was inconsistent with practice (p = .02). Fewer than 35% reported that they provide fluoride to adults of any age, or they wait until the disease is present. For children and adults who did receive fluoride treatments, a one-minute application of an APF gel or foam was most often provided. CONCLUSIONS: Correct information about the etiology and prevention of dental caries is a predisposing factor to making informed decisions. Overall, respondents overrated the effectiveness of flossing and toothbrushing while underrating the effectiveness of fluorides. In the majority of cases, efficiency rather than efficacy was given priority when providing a topical fluoride treatment. An improved understanding of dental caries etiology and the scientific evidence for appropriate caries preventive procedures will allow dental hygienists to prevent and manage this disease better.

Acidulated Phosphate Fluoride↗

PubMed1988

Effects of a sodium fluoride solution and a varnish with different fluoride concentrations on enamel remineralization in vitro.

To study the efficacy of sodium fluoride varnishes and a NaF solution in remineralization of enamel, 120 slabs of non-carious human enamel enamel were presoftened for 6 h and randomly divided into six groups. The slabs were stored in synthetic saliva for 9 days, except for a daily 30-min immersion in 0.1 M lactic acid-NaOH buffer. During the 9-day period, one group of the slabs received no treatment, and the rest were treated once or three times with 2.3% or 1.1% sodium fluoride varnish Duraphat, or nine times with a 0.1% NaF solution. Finally, the slabs were demineralized for 1 h, and the amount of dissolved Ca and F was determined. Microhardness of enamel was determined initially, after presoftening, after the 9-day period, and after the 1-h demineralization. All fluoride treatments prevented enamel softening almost completely during the 9 days, but the control slabs softened markedly. Fluoride varnishes were more effective than NaF solution. Three applications of 2.3% Duraphat were slightly more effective than any of the other varnish treatments, but one treatment with 2.3% varnish was not more effective than treatments with 1.1% varnish. Enamel treated three times with 1.1% varnish showed the greatest acid resistance during the 1-h demineralization. The results suggest that the efficacy of the varnish was not proportional to the fluoride concentration but rather to the number of applications. Fluoride uptake by enamel was greatest with the most concentrated varnish. Enamel solubility was not, however, directly proportional to the fluoride content of enamel.

Dental Caries↗

PubMed1998

Effect of toothpicks with and without fluoride on De- and remineralization of enamel and dentine in situ.

The aim of this investigation was to study the effect of the interproximal use of fluoride (F)-impregnated and non-impregnated birch toothpicks on the degree of de- and remineralization of enamel and dentine in situ. Ten volunteers with complete dentures in the upper jaw participated. Each subject had four specimens: (1) sound enamel, (2) demineralized enamel, (3) sound dentine and (4) demineralized dentine; placed pairwise at two approximal sites (15/16 and 25/26) of the maxillary prosthesis. The study involved three test periods (A, B and C), each lasting 4 weeks. In A, the subjects used F toothpicks (impregnated in 4% NaF) and, in B, nonimpregnated toothpicks 3 times daily. During period C, no toothpicks were used. Dentifrice or other F-containing products were not allowed during the 4-week periods. Transversal microradiography was used to determine lesion depth (ld) and mineral loss (DeltaZ). The results revealed that all the sound samples lost mineral during the three experimental periods; DeltaZ for both enamel and dentine was less for A and B compared with C (p<0.01) and less for A compared with B and C for dentine (p<0.05, p<0.01). The demineralized samples also lost mineral, apart from dentine, during periods A and B, i.e. when F-impregnated and non-impregnated toothpicks were used; ld for enamel and DeltaZ for dentine were less for A compared with C (p<0.05). Four weeks' use of toothpicks, especially F-impregnated toothpicks, thus reduces the demineralization of enamel and dentine at approximal sites in situ.

Aged↗

PubMedDate not supplied

Physiological remineralization of artificially demineralized dentin beneath glass ionomer cements with and without bacterial contamination in vivo.

This study evaluated the physiological remineralization of artificially demineralized dentin beneath glass ionomer cements with and without bacterial contamination. The artificially demineralized dentin was produced on 84 monkey teeth using a decalcifying solution. Half the samples were left open to the oral cavity for one week, then, all cavities were restored with two glass-ionomer cements: Fuji IX or Fuji II LC improved (n = 7). The nanohardness of the artificially demineralized dentin at 3, 90 and 360 days was measured using a nanoindentation tester (ENT-1100, Elionix) and compared statistically by two-way ANOVA and Fisher's PLSD test (p < 0.05). Each mineral (Ca, Mg, P, F) within the demineralized dentin was also analyzed using Electron Probe Microanalysis. For the samples, the mean nanohardness of the three-day samples was significantly lower than the 360-day samples (p < 0.05). Although there was no significant difference in the mean nanohardness within all the bacterially-contaminated groups through the experimental periods (p > 0.05), the mean nanohardness of the bacterial-contaminated samples were significantly lower than the non-bacteria-contaminated samples (p < 0.05). From the EPMA results, fluoride release from both cements to the bottom of the artificially demineralized dentin was detected within three days. Although Ca density was sparse within this demineralized dentin lesion, for the Fuji IX sample, a high Mg density within this lesion was detected at 360 days.

Analysis of Variance↗