pH-cycling models to evaluate the effect of low fluoride dentifrice on enamel de- and remineralization

Since the currently available pH-cycling models do not differentiate the anti-caries potential of dentifrices with low fluoride (F) concentration, two models were developed and tested in the present. Bovine enamel blocks were subjected to the models and treated with F solutions containing from 70 to 280 mug F/mL in order to validate them in terms of dose-response effect. The models were also tested by evaluating the dentifrices Colgate Baby (500 mug F/g, as a low fluoride dentifrice), Tandy (1,100 mug F/g, as an active F-dentifrice) and Crest (1,100 mug F/g, as positive control). Enamel mineral loss or gain was assessed by surface and cross-sectional microhardness, and lesion depth was analyzed by polarized light microscopy. The pH-cycling models showed F dose-response effect either reducing enamel demineralization or enhancing remineralization. The low F dentifrice presented anti-caries potential, but it was not equivalent to the dentifrices containing 1,100 mug F/g. These data suggest that the models developed in this study were able to evaluate the anti-caries potential of low F dentifrice either on resistance to demineralization or on enhancement of remineralization.

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A modified pH-cycling model to evaluate fluoride effect on enamel demineralization

Pesquisa Odontológica Brasileira ◽

10.1590/s1517-74912003000300008 ◽

2003 ◽

Vol 17 (3) ◽

pp. 241-246 ◽

Cited By ~ 45

Author(s):

Rosane Maria Orth Argenta ◽

Cinthia Pereira Machado Tabchoury ◽

Jaime Aparecido Cury

Keyword(s):

Dose Response ◽

Significant Negative Correlation ◽

Enamel Surface ◽

Cross Sectional ◽

Enamel Demineralization ◽

Human Enamel ◽

Ph Cycling ◽

Dose Response Effect ◽

Mineral Loss

Since in vitro pH-cycling models are widely used to study dental caries, they should allow evaluations of fluoride effect on early stages of caries development. Therefore, acid etching on enamel surface must be avoided, enabling surface microhardness (SMH) analysis. In the present study, the pH-cycling model originally described by Featherstone et al.9 (1986) was modified to preserve the enamel surface and to produce early carious lesions that could be evaluated using SMH and cross-sectional microhardness (CSMH) measurements. In order to validate this modified model, a dose-response evaluation with fluoride was made. Human enamel blocks with known SMH were submitted to such regimen with the following treatments: distilled deionized water (DDW; control) and solutions containing 70, 140 and 280 ppm F. Data from %SMH change and deltaZ (mineral loss) showed a statistically significant negative correlation between F concentration in treatment solutions and mineral loss. In conclusion, the modified pH-cycling model allowed the evaluation of changes on the outermost enamel layer during caries development, and a dose-response effect of fluoride reducing enamel demineralization was observed.

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Histological and microhardness evaluation of early artificial carious lesions in human and bovine enamel: in vitro study

Brazilian Dental Science ◽

10.14295/bds.2013.v16i4.929 ◽

2013 ◽

Vol 16 (4) ◽

pp. 49

Author(s):

Allan Kenji Masuda ◽

Mayra Fidelis Zamboni Quitero ◽

Luciana Cardoso Espejo-Trung ◽

Maria Aparecida Alves Cerqueira Luz

Keyword(s):

Polarized Light ◽

In Vitro Study ◽

The Body ◽

Polarization Microscopy ◽

Cross Sectional ◽

Enamel Caries ◽

Carious Lesions ◽

Ph Cycling ◽

Bovine Enamel

Objective: Early carious lesions in bovine and humanenamel developed in vitro using a pH cycling regimenwere compared. Material and Methods: Fifteencentral bovine incisors and fifteen recently extractedhuman third molars were randomly divided into twogroups: ten for the cross-sectional microhardness test(MT) and five for polarized light microscopy (PLM)analysis. Enamel blocks measuring 5 x 5 mm weremade from the buccal face of the teeth. The blocksused for the MT were sliced into two halves: “A” and“B”. “A” slices were embedded in acrylic resin, withthe face of the dentin-enamel junction left exposedfor the MT prior to pH cycling. “B” slices and wholeblocks were coated with acid-resistant varnish,except a 3 x 3 mm central window, and submitted tothe pH cycling regimen (demineralizing solution for3 h and remineralizing solution for 21 h) over fiveconsecutive days. The “B” slices were then submittedto the MT and the whole blocks were processed forthe PLM study. Results: The PLM analysis revealedshallow, extensive lesions in the bovine enamel,hardly showing the superficial, dark and translucentzones, as well as deep cavity lesions in the humanenamel, with the body of the lesion and the darkzone evident. The MT revealed a significant decreasein microhardness in the superficial levels of thebovine enamel caries and at all depth levels of thehuman enamel caries. Conclusion: The pH cyclingregimen adopted led to the development of deeperand more demineralized carious lesions in humanenamel than bovine enamelKeywords Dental caries; Dental enamel; Microhardness tests; Polarization microscopy.

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Dose–response effect of fluoride dentifrice on remineralisation and further demineralisation of erosive lesions: A randomised in situ clinical study

Journal of Dentistry ◽

10.1016/j.jdent.2015.03.008 ◽

2015 ◽

Vol 43 (7) ◽

pp. 823-831 ◽

Cited By ~ 10

Author(s):

J.E. Creeth ◽

S.A. Kelly ◽

E.A. Martinez-Mier ◽

A.T. Hara ◽

M.L. Bosma ◽

...

Keyword(s):

Clinical Study ◽

Dose Response ◽

Response Effect ◽

Fluoride Dentifrice ◽

Dose Response Effect

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Anticariogenic potencial of acidulate solutions with low fluoride concentration

Journal of Applied Oral Science ◽

10.1590/s1678-77572006000400004 ◽

2006 ◽

Vol 14 (4) ◽

pp. 233-237 ◽

Cited By ~ 5

Author(s):

Alberto Carlos Botazzo Delbem ◽

Gilberto Carlos Tiano ◽

Karina Mirela Ribeiro Pinto Alves ◽

Robson Frederico Cunha

Keyword(s):

Citric Acid ◽

Dose Response ◽

Fluoride Concentration ◽

Response Relationship ◽

Surface Microhardness ◽

Dose Response Relationship ◽

Mouth Rinses ◽

Ph Cycling ◽

Bovine Enamel ◽

Mineral Loss

OBJETIVES: The aim of this study was to verify the anticariogenic effect of acidulate solutions with low NaF concentration, using pH-cycling model and bovine enamel. MATERIAL AND METHODS: Enamel blocks were submitted to the surface microhardness (SMH) test and randomly divided in 12 experimental and one placebo groups. The blocks were submitted to pH cycling for 7 days, with daily applications once/day of 0.05% NaF and 0.1% NaF and twice/day of 0.02% NaF solutions. Four different pH: 4.0, 5.0, 6.0 and 7.0 were used. Next, SMH test was again used to determine the surface microhardness percentage change (%SMH). Data obtained for %SMH were homogeneous and passed through variance analyses and Tukey's test (5%) as far as fluoride concentrations and pH. RESULTS:The results showed that pH influenced %SMH in 0.02% NaF and 0.05% NaF solutions with pH 4.0, which had less mineral loss compared to pH 7.0 (p<0.05). The 0.02% NaF - pH 4.0, and 0.05% NaF - pH 7.0 groups showed similar results (p>0.05). A dose-response relationship was observed among the tested solutions, with better anticariogenic effect for the 0.1% NaF solution. CONCLUSION: The results suggest that the addition of citric acid to acidulate mouth rinses reduce mineral loss.

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Efficacy of S-PRG filler containing varnishes on enamel demineralization prevention

Scientific Reports ◽

10.1038/s41598-020-76127-w ◽

2020 ◽

Vol 10 (1) ◽

Author(s):

Manuela da Silva Spinola ◽

Sabrina Elise Moecke ◽

Natália Rivoli Rossi ◽

Toshiyuki Nakatsuka ◽

Alessandra Bühler Borges ◽

...

Keyword(s):

Positive Control ◽

Negative Control ◽

Cross Sectional ◽

Enamel Demineralization ◽

Ph Cycling ◽

Knoop Microhardness ◽

Bovine Enamel ◽

Demineralization Prevention ◽

Unprotected Area ◽

One Way Anova

Abstract This study evaluated the efficacy of S-PRG vanishes on preventing enamel demineralization. Bovine enamel specimens were obtained, polished and the baseline Knoop microhardness was evaluated. Specimens were stratified into six groups (n = 15), according to the varnish applied: S10—experimental varnish containing 10% of S-PRG fillers, S20—20% of S-PRG fillers, S30—30% of S-PRG fillers; S40—40% of S-PRG fillers; PC (positive control)—5% of NaF; NC (negative control)—no treatment was performed. Half of enamel surfaces were protected to work as a control and varnishes were applied over the unprotected area. A demineralizing pH-cycling was performed, and surface and cross-sectional microhardness were measured. The percentage of microhardness of the treated area was calculated comparing with the untreated area. Statistical analysis was performed by one-way ANOVA and Tukey’s test (p = 5%). All experimental S-PRG varnishes protected against demineralization in relation to no treatment, but S40 was the most effective on the surface. For all depths, S30 and S40 were superior in enamel demineralization prevention than other S-PRG filler concentrations and 5% NaF. It was concluded that S-RPG filler containing varnishes were effective to prevent enamel demineralization. The higher concentrated products were more effective than 5% sodium fluoride on surface demineralization prevention.

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Is Speed of Onset of Anti-anxiety Efficacy with Pregabalin Influenced by Starting Dose?

European Psychiatry ◽

10.1016/s0924-9338(09)70762-x ◽

2009 ◽

Vol 24 (S1) ◽

pp. 1-1

Author(s):

B. Herman ◽

F. Mandel

Keyword(s):

Dose Response ◽

Change Score ◽

Early Improvement ◽

Response Effect ◽

Starting Dose ◽

Dsm Iv ◽

The Mean ◽

Dose Response Effect ◽

Titration Schedule ◽

Speed Of Onset

Objective:There appears to be no dose-response effect for pregabalin at doses of 300-600 mg, and a modest dose-response effect in the range of 150-300 mg. The goal of the current investigation was to determine the effect of the starting dose on the speed of onset of anxiolytic efficacy.Methods:Data were analyzed from 7 trials of outpatients with DSM-IV GAD and a HAM-A total score ≥18. Starting doses of pregabalin ranged from 100 mg (N=301) or 150 mg (N=104), to 200 mg (N=167) and 300 mg (N=388). Assessment of early improvement included the HAM-A total score and CGI-Severity and Improvement scores.Results:The mean Week 1 HAM-A change score was similar for a starting dose of 200 mg/d with no titration (-8.24) when compared to patients who started on 200 mg/d and then titrated up to 400 mg/d on Day 4 (-8.64). The mean Week 1 HAM-A change score was somewhat higher for patients started on 300 mg/d, and then titrated to 450 mg/d on Day 4/5 (-8.84) when compared to patients started on a lower (100/150 mg/d) dose and titrated on Day 5 to 400/450 mg/d (-7.32). Starting on a dose of 300 mg/d with no titration resulted in an intermediate Week 1 change score (-7.87). The interaction of starting dose and titration schedule with baseline anxiety severity will be summarized in detail.Conclusion:The initial dose of pregabalin appears to have only a weak effect on the speed of onset of anxiolytic improvement.

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