The role of fluoride and casein phosphopeptide/amorphous calcium phosphate in the prevention of erosive/abrasive wear in an in vitro model using hydrochloric acid

OBJECTIVE: To investigate the effect of various fluoride compounds and casein phosphopeptide/amorphous calcium phosphate (CPP-ACP) on the reduction of erosive/abrasive tooth wear. METHODS: Forty enamel samples were prepared from bovine lower incisors, stratified and allocated to 4 groups (1-4). Samples in group 1 remained untreated and served as negative controls. The test samples were treated for 2 min/day as follows: group 2 amine/sodium fluoride gel (pH 4.8; 12,500 ppm), group 3 sodium fluoride gel (pH 7.1; 12,500 ppm) and group 4 CPP-ACP-containing mousse. De- and remineralization cycling was performed for 20 days with 6 erosive attacks for 20 s with HCl (pH 3.0) per day. Samples were stored in artificial saliva between cycles and overnight. Toothbrushing (15 s; 60 strokes/min; load 2.5 N) with a toothpaste slurry was performed each day before the first and 1 h after the last erosive exposure. Tooth wear was measured by comparing baseline surface profiles with the corresponding posttreatment profiles. RESULTS: Tooth wear was significantly reduced in groups 2 and 3 compared with group 1, while the enamel loss of group 4 was not significantly lower compared to the negative control group 1. Between the fluoride groups 2 and 3, no significant difference in tooth wear was recorded. CONCLUSION: Erosive/abrasive tooth wear under the conditions used could be reduced significantly by the daily application of fluoride gels, irrespective of the fluoride compound, while the application of CPP-ACP-containing mousse was less effective

Is bovine dentine an appropriate substitute in abrasion studies?

The study aimed to compare the wear behaviour of human and bovine dentine due to toothbrushing with different relative dentin abrasivity (RDA) toothpastes. Forty human and 40 bovine dentine samples were prepared from bovine lower incisors or human premolars roots, and baseline surface profiles were recorded. The samples were distributed to four groups (each group n = 10 human and 10 bovine samples) and brushed with fluoridated experimental toothpastes with different RDAs (group A: RDA 10, B: RDA 20, C: RDA 50, and D: RDA 100). Toothbrushing was performed in an automatic brushing machine with a brushing frequency of 60 strokes per minute and a brushing force of 2.5N. After 2, 5, 10, and 25min of toothbrushing, new surface profiles were recorded, and the dentine wear was calculated with a customised computer programme. The dentine wear of human and bovine dentine within the four groups was compared with unpaired t tests. No statistically significant difference was recorded for the dentine wear of human and bovine samples within the different group

Salivary Flow Rate During Toothbrushing

PURPOSE To determine the salivary flow rate and subsequent dilution of toothpaste and assess the pH of oral fluids during toothbrushing with toothpastes of various pHs. MATERIALS AND METHODS The study was conducted as an in-vivo trial involving 30 healthy volunteers. The participants took part in a series of trials distributed over four appointments. After a screening check, in which the participants' stimulated and unstimulated salivary flow rate and buffering capacities were determined, four test series involving toothbrushing were conducted. Participants brushed their teeth using a manual toothbrush for 2 min: once without toothpaste and three times using toothpastes of varying pHs. The salivary flow rate and subsequent dilution of the toothpaste was determined. Additionally, the pH of the collected oral fluid was analysed. RESULTS Brushing teeth with toothpaste caused a statistically significant increase in salivary flow rate (median/IQR in ml/min) (Elmex Kariesschutz 3.29/1.36, Colgate Total Original 3.23/1.08, Elmex Sensitive Professional 3.18/1.39) when compared to brushing teeth using a manual toothbrush without toothpaste (1.85/0.78) (p < 0.05). The variation in pH of the oral fluid samples was dictated primarily by the pH of the toothpaste used. CONCLUSION The salivary flow rate when brushing using toothpaste was similar across all tested toothpastes, independent of pH, and had an average median of 3.23 ml/min. The dilution of 1 g of toothpaste during a standard toothbrushing procedure of 2 min is therefore approximately at a ratio of one part toothpaste to 6.5 parts saliva

Colour improvement and stability of white spot lesions following infiltration, micro-abrasion, or fluoride treatments in vitro

SUMMARYBACKGROUND/OBJECTIVES: White spot lesions (WSLs) are unwelcome side effects of fixed appliances that compromise the treatment outcome. Recently, infiltration of WSLs has been introduced as a viable treatment alternative. The objective was to evaluate the colour improvement of WSLs and their stability against discolouration following infiltration, fluoride, or micro-abrasion treatments in vitro. MATERIALS/METHODS: Artificial WSLs were created in bovine enamel (N = 96) using acidic buffer solution (pH 5, 10 days) and were randomly allocated to four groups. Specimens were treated with infiltration (Icon, DMG), fluoride (Elmex Caries Protection, GABA), and micro-abrasion (Opalustre, Ultradent) or remained untreated (control). Groups were discoloured for 24 hours in tea or tea + citric acid. Colour components and visible colour change (L*, a*, b*, ΔE) were measured spectrophotometrically on following time points: baseline, after WSL formation, after treatment, and during discolouration (8, 16, and 24 hours). Data were analysed using Kruskal-Wallis and Mann-Whitney tests. RESULTS: WSL formation increased (L*) in all groups. Only infiltration reduced this effect to baseline. Highest ΔE improvement was obtained by infiltration and micro-abrasion followed by fluoride. This improvement was stable only for infiltration during discolouration. L*, a*, and b* changed significantly during discolouration in all groups except infiltration. Within the same treatment group, discolouration solutions did not differ significantly. LIMITATIONS: In vitro testing cannot replicate the actual mode of colour improvement or stability but can be used for ranking materials and techniques. CONCLUSIONS/IMPLICATIONS: Infiltration and micro-abrasion treatments were capable of diminishing the whitish appearance of WSLs. Only infiltrated WSLs were stable following discolouration challeng

Von Konkurrenz kann keine Rede sein! Zur Bedeutung von familien- und sozialpolitischen Maßnahmen im historischen Verlauf der Frauenindustriearbeit in Deutschland

Die folgenden Überlegungen stammen aus einer historisch orientierten Untersuchung zur Entwicklung der Frauenindustriearbeit in Deutschland. Die historische Orientierung verfolgt dabei eine doppelte Zielsetzung. Zum einen kann die vorfindliche Situation der Frauenerwerbstätigkeit, die gekennzeichnet ist durch die aktuellen Formen der Benachteiligung, nur aus ihrer Geschichte geklärt werden. Sie muß als Resultat einer Entwicklung begriffen werden, die trotz einer Fülle von politischen und sozialpolitischen Versuchen, die ökonomische Benachteiligung der weiblichen Arbeitskraft aufzuheben, lediglich auf jeweils neuer Ebene die Diskriminierung der Frauen im Erwerbsleben stabilisierte. Zum anderen kann so ein falscher ökonomischer Determinismus umgangen werden. Die jeweilige Verwertungssituation der Branche (Art der Produktionsprozesse und Möglichkeiten sowie Stand der Mechanisierung dieser Prozesse) ist nicht ausschließlich bedeutsam für den Fraueneinsatz. Ein weiterer zumindest gleichbedeutender Faktor ist sicher in der historischen Entwicklung der Industriezweige zu sehen: Der ursprünglich hauptsächlich durch typische weibliche Fertigkeiten und Eigenschaften gerechtfertigte Einsatz von Frauen in bestimmten Produktionsbereichen (z.B. Textil- und Bekleidungsindustrie sowie Nahrungs- und Genußmittelindustrie) besteht auch noch unter technisch entwickelteren Niveaus fort, die solche Fertigkeiten gar nicht mehr verlangen

Impact of laminar flow velocity of different acids on enamel calcium loss

Objective: The aim of the study was to evaluate the impact of flow velocity under laminar flow conditions of different acidic solutions on enamel erosion. Material and methods: A total of 240 bovine enamel specimens were prepared and allocated to 30 groups (n = 8 each). Samples of 18 groups were superfused in a flow chamber system with laminar flow behavior using 1ml of citric acid or hydrochloric acid (HCl) of pH 2.0, 2.6 or 3.0. Flow rates in the sample chamber were adjusted to 10, 60 or 100μl/min. To simulate turbulent flow behavior, samples of six groups were immersed in 1ml of the respective solution, which was vortexed (15min, 600rpm). For simulating non-agitated conditions, specimens of the remaining six groups were immersed in 1ml of the respective solution without stirring. Calcium in the solutions, released from the enamel samples, was determined using Arsenazo III method. Results: For acidic solutions of pH 2.6 and 3.0, erosive potential of citric acid was equivalent to that of HCl at a flow of 100μl/min. The same observation was made for the samples subjected to turbulent conditions at pH 3. At all other conditions, citric acid induced a significantly higher calcium loss than HCl. Conclusion: It is concluded that under slow laminar flow conditions, flow rate variations lead to higher erosive impact of citric acid compared to hydrochloric acid at pH 2.0, but not at pH ≥ 2.6 and increasing laminar flow or turbulent conditions. Clinical relevance: Erosive enamel dissolution under laminar flow conditions is a complex issue influenced by flow rate and acidic substrat

In vitro evaluation of fissure sealants’ wear under erosive, abrasive and erosive/abrasive conditions

Purpose To evaluate and compare the wear of selected resin-based fissure sealants with different compositions properties under erosive, abrasive, and erosive/abrasive conditions. Methods Forty-five samples of the following resin-based fissure sealants were prepared: Fissurit (fluoride free), Fissurit F (with fluoride), Fissurit FX (55 wt.% filler content), Grandio Seal (70 wt.% nano-filler content) and bovine enamel. Fifteen samples from each material were randomly allocated into three groups according to the wear condition they would be subjected to as follows: erosive condition (citric acid, 1 min, pH 2.3), abrasive condition (120 brushing strokes at 2 N, toothpaste slurry RDA value = 69), and erosive/abrasive condition (combination of both). The wear challenges were repeated six times each day for 10 days. The material wear was measured using a stylus profilometer. Kruskal–Wallis and Conover’s test was applied to compare the resulting material wear between the groups. Results Under erosive conditions, Grandio Seal and Fissurit FX showed statistically significantly the least material wear. Under abrasive and erosive/abrasive conditions, Grandio Seal showed statistically significantly the least material wear. Fissurit F showed statistically significantly the highest material wear under abrasive and erosive/abrasive conditions, after dental enamel (p < 0.05). Conclusion Higher filler content in sealants leads to better wear resistance. Incorporating fluoride into sealants seems to reduce their wear resistance at similar filler contents

Abrasive Enamel and Dentin Wear Resulting from Brushing with Toothpastes with Highly Discrepant Relative Enamel Abrasivity (REA) and Relative Dentin Abrasivity (RDA) Values

PURPOSE To investigate the absolute wear caused by toothpastes with highly discrepant REA (Relative Enamel Abrasivity) and RDA (Relative Dentin Abrasivity) values on both enamel and dentin: Candida Peppermint (CP; REA: 1; RDA: 42), Colgate Total Original (CTO; REA: 4; RDA: 100), Signal White System (SWS; REA: 8; RDA: 143), and Candida White Diamond (CWD; REA 244; RDA: 12). MATERIALS AND METHODS Eighty (80) bovine enamel samples and 80 dentin samples were divided into four groups each (n = 20) and investigated after a 6-h brushing procedure (21,600 cycles, 60 cycles/min, load of 2.5 N) with the four toothpastes. The abrasive enamel and dentin wear were registered using a contact profilometer. The median and interquartile range (IQR) of the abrasive enamel and dentin wear were calculated for each group. Pairwise comparisons were conducted using the Wilcoxon signed-rank exact test, and the p-value was adjusted according to Holm (statistical significance set at 0.05). RESULTS CWD led to the highest abrasive enamel wear (9.86 μm [5.77]). CTO caused the highest abrasive dentin wear (166.70 μm [69.90]), being statistically significantly higher than the wear for CP (54.20 μm [24.00]) and CWD (17.00 μm [7.80]) (p = 0.00001). The abrasive dentin wear for CWD was statistically significantly lower in comparison to all other groups (p = 0.00001). CONCLUSION Toothpastes with highly discrepant REA and RDA values presented statistically significantly different absolute wear on enamel and dentin. REA and RDA values should both be declared for every toothpaste

Supplementation of Energy Drinks with Green Tea Extract: Effect on In Vitro Abrasive/Erosive Dentin Wear

PURPOSE: To investigate the effect of the supplementation of energy drinks with green tea extract on abrasive and erosive dentin wear. MATERIALS AND METHODS: Six groups, each comprising 15 bovine dentin samples, were prepared, yielding a total of 90 samples. Erosion was performed by immersing the samples in Red Bull and Red Bull light with and without green tea extract. Tap water with and without green tea extract was used as the control groups. The samples were subjected to abrasive/erosive cycling for five days. The following cycling was performed daily: toothbrush abrasion (20 brushstrokes; 2.5 N); eight erosive cycles (2 min storage in the respective solutions); in between the erosive cycles, storage in artificial saliva (60 min) and again toothbrush abrasion (20 brushstrokes; 2.5 N). During the night, samples were again stored in artificial saliva. Abrasive/erosive dentin wear was measured using a stylus profilometer (µm, accuracy = 40 nm). The measured dentin loss results from the vertical position shift on the y-axis from base to final profile after the wear process in 2D. Pairwise comparisons between the groups were carried out using Wilcoxon signed-rank test. RESULTS: The following dentin wear (median [IQR]) was measured: Red Bull: 1.9 µm (0.5); Red Bull Light: 1.3 µm (0.3); Red Bull with green tea extract: 0.8 µm (0.3); Red Bull Light with green tea extract: 0.3 µm (0.5); Tap water with green tea extract: -0.2 µm (0.7); Tap water: -1.0 µm (1.2). The comparison of all tested groups to each other proved to be statistically significant (p < 0.05). CONCLUSION: The supplementation of energy drinks with green tea extract provide a protective effect against erosive/abrasive wear in vitro

Effect of a sonic toothbrush on the abrasive dentine wear using toothpastes with different abrasivity values

OBJECTIVE This in vitro study aimed to investigate the effect of a sonic toothbrush on the resulting abrasive dentine wear using toothpastes with different abrasivities compared to the use of a manual toothbrush. METHODS Ninety-six bovine dentine samples were divided into six groups and subjected to a brushing sequence (sonic: 20 min, 0.9 N, 10 strokes/min; manual: 20 min, 1.6 N, 60 strokes/min) as follows: group 1: Elmex Sensitive Plus (RDA = 28) + manual toothbrush; group 2: Elmex Sensitive + sonic toothbrush; group 3: Elmex Kariesschutz (RDA = 65) + manual toothbrush; group 4: Elmex Kariesschutz +sonic toothbrush; group 5: Colgate Total Original (RDA = 121) + manual toothbrush; and group 6: Colgate Total Original +sonic toothbrush. The abrasive dentine wear was measured profilometrically. RESULTS The median (IQR) abrasive dentine wear was as follows: Elmex Sensitive Plus (manual toothbrush: 2.7 µm (0.8), sonic toothbrush: 3.1 µm (1.9)); Elmex Kariesschutz (manual toothbrush: 4.9 µm (1.4), sonic toothbrush: 6.4 µm (2.1)); and Colgate Total Original (manual toothbrush: 5.2 µm (1.1), sonic toothbrush: 9.0 µm (3.1)). Differences in dentine wear between sonic and manual toothbrushes were statistically significant only in the groups brushed with Elmex Kariesschutz and Colgate Total Original (p ≤ 0.05). CONCLUSION Brushing with a sonic toothbrush could result in a higher abrasive dentine wear compared to manual toothbrush when combined with toothpastes with high abrasivity values