Influence of different toothpaste abrasives on the bristle end-rounding quality of toothbrushes.

OBJECTIVES: To evaluate the influence of different toothpaste abrasives on the bristle wear and bristle tip morphology of toothbrushes with different degrees of hardness. MATERIAL AND METHODS: Ninety samples of bovine incisor teeth were used in this study. The samples were randomly divided into three groups according to the bristle hardness of the toothbrush used: soft bristles (S); extra-soft bristles (ES); hard bristles (H). The toothbrushes of each group were randomly divided into six subgroups with five toothbrushes each, according to the abrasive of the toothpaste used in the simulation: Negative control (distilled water); toothpaste 1 (silica); toothpaste 2 (hydrated silica); toothpaste 3 (calcium carbonate, calcium bicarbonate and silica); toothpaste 4 (tetrapotassium pyrophosphate, silica and titanium dioxide); toothpaste 5 (calcium carbonate). The samples were placed in a toothbrushing simulating machine that simulating three months of brushing. The toothbrush bristles were evaluated by the bristle wear index, and the bristle tips morphology was evaluated by the bristle tip morphology index. RESULTS: The ES brush presented the highest bristle wear among the toothbrushes. Additionally, the S brushes showed better morphology of the bristles followed by ES and H brushes. The type of abrasive only influenced the bristle tip morphology of the ES brushes. The toothpaste 3 induced the worse bristle tip morphology than all the other toothpastes. CONCLUSIONS: Different abrasives have influence only on the bristle tip morphology of the ES brushes.

Una década de monitoreo de plomo en sangre en niños escolares del área metropolitana de Monterrey, NL / A decade of lead monitoring in schoolchildren in the metropolitan area of Monterrey NL, Mexico

Objetivo. Establecer las concentraciones de plomo (Pb) en sangre en niños escolares de 1998 y 2008, así como su asociación con factores de riesgo. Material y métodos. Se llevó a cabo un monitoreo de Pb en sangre de niños de entre 6 y 12 años que cursan educación primaria en 17 escuelas diferentes, ubicadas en distintas zonas del área metropolitana de Monterrey, de 1998 a 2008. Resultados. Se obtuvieron niveles séricos de 9.6 ± 3.0 (µg/dL rango de 3.18 a 20.88) en 1998 y de 4.5±4.8 µg/dL (rango de 3.3 a 53.7) en 2008, lo que mostró una disminución de 2.1 veces en nivel de Pb (p<0.01). Conclusiones. La reducción de los niveles séricos de Pb demuestran los mejores controles ambientales e industriales y probablemente el éxito de retirar el Pb de la gasolina durante los años noventa.

Objective. To establish the blood lead concentration and associated risk factors in schoolchildren during 1998 and 2008. Materials and methods. A blood lead screening was conducted in schoolchildren of 6-12 years of age, enrolled in 17 elementary schools of the metropolitan area of Monterrey, México, during 1998 and 2008. Results. The mean blood lead level were 9.6 ± 3.0 (µg/dL range of 3.18 to 20.88) in 1998 and 4.5±4.8 µg/dL (range of 3.3 to 53.7) showing a 2.1-times reduction in blood lead levels (p<0.01). Conclusions. This reduction in blood lead levels demonstrate environmental and industrial control improvements and the benefits of fading out the leaded gasoline during the 1990's.

Effect of brushing and accelerated ageing on color stability and surface roughness of composites.

OBJECTIVES: The aim of this study was to evaluate the effect of brushing and artificial accelerated ageing (AAA) on color stability and surface roughness of aesthetic restorative materials. METHODS: One hundred and twenty specimens (12 mm diameter × 2 mm thick), 40 of each material (n=8) were obtained using nanosized composite Z350 (3M ESPE), nanohybrid composite Tetric N-Ceram (Ivoclar Vivadent) and ceramic IPS e.max Ceram (Ivoclar Vivadent), as control. Initial color (Spectrophotometer PCB 6807) and surface roughness (Surfcorder SE 1700) readouts were taken and the samples were separated into five groups (n=8) and treated as follows: Group 1: mechanical brushing with dentifrice RDA* 68 (Colgate), Group 2: mechanical brushing with dentifrice RDA* 180 (Colgate Total Plus Whitening), Group 3: AAA, Group 4: AAA followed by mechanical brushing with dentifrice RDA* 68 and Group 5: AAA followed by mechanical brushing with dentifrice RDA* 180. Mechanical brushing was performed for 205 min and AAA for 480 h; new color and surface roughness readouts were taken. Data were statistically analyzed (two-way ANOVA repeated measures, Bonferroni test, p<0.05). RESULTS: Dentifrice abrasiveness was not significant for color change and surface roughness. When submitted to AAA+brushing, the color stability of Tetric was statistically significant (p<0.05) with both dentifrices and with dentifrice RDA* 180 for Z350. The roughness was different (p<0.05) for Z350 when brushed with RDA* 68 after AAA. CONCLUSIONS: Dentifrice abrasiveness did not interfere in the ability to remove stains and roughness from aged samples. However, staining is material-dependent. CLINICAL SIGNIFICANCE: The abrasiveness of dentifrice does not change the color and surface roughness of the composites and does not help to remove surface stains from the aged samples.

Comparative investigation of the efficacy of triclosan/copolymer/sodium fluoride and stannous fluoride/sodium hexametaphosphate/zinc lactate dentifrices for the control of established supragingival plaque and gingivitis in a six-month clinical study.

OBJECTIVE: This double-blind clinical study, conducted at the University of Puerto Rico, San Juan, Puerto Rico, was designed to compare the efficacy of two commercially available dentifrices for the control of supragingival plaque and gingivitis. METHODS: Qualifying adult male and female subjects from the San Juan, Puerto Rico area were randomly assigned to one of two treatment groups: 1) a commercially available dentifrice containing 0.3% triclosan, 2.0% PVM/MA copolymer, and 0.243% sodium fluoride (Colgate Total); and 2) a commercially available dentifrice containing 0.454% stannous fluoride, sodium hexametaphosphate, and zinc lactate (Crest Pro-Health). All subjects received an oral soft and hard tissue examination, and were dispensed their assigned dentifrice product, along with a soft-bristled adult toothbrush for home use. Subjects were instructed to brush their teeth for one minute, twice daily (morning and evening), using only the dentifrice provided. Examinations for supragingival plaque and gingivitis, and oral soft and hard tissue assessments were repeated after six weeks, three months, and six months of product use. RESULTS: One-hundred and nine (109) subjects complied with the protocol and completed the six-month examinations. At the six-month examination, both treatment groups exhibited statistically significant reductions from baseline with respect to supragingival plaque and gingivitis scores. Relative to the Crest Pro-Health Toothpaste group, the Colgate Total Toothpaste group exhibited statistically significant reductions in supragingival plaque index scores of 18.5%, 20.7%, and 25.8% after six weeks, three months, and six months of product use, respectively. For gingival index scores, statistically significant reductions of 20.5%, 18.9%, and 17.1% were exhibited after six weeks, three months, and six months of product use, respectively. CONCLUSION: The results of this double-blind clinical study support the conclusion that a dentifrice containing 0.3% triclosan, 2.0% PVM/MA copolymer, and 0.243% sodium fluoride provides a significant reduction in established supragingival plaque and gingivitis, as compared to a dentifrice containing 0.454% stannous fluoride, sodium hexametaphosphate, and zinc lactate when used over a period of six months.

Luminescence quenching of tris(2,2'-bipyridine)ruthenium(II) by 2,6-dimethylphenol and 4-bromo-2,6-dimethylphenol in sol-gel-processed silicate thin films.

The luminescence properties of tris(1,2-bipyridine)ruthenium(II) (Ru(bpy)(3)(2+)), included in different organically modified silicate gel matrixes were investigated. Spin and dip-coated thin films were prepared from methyltrimethoxysilane (MTMOS) and methyltriethoxysilane (MTEOS). A blue shift in the emission spectrum of the MLCT excited state of Ru(bpy)(3)(2+) with respect to the aqueous solution was observed in all the films, practically independent of the reaction pH used to prepare the "sol," silane-derived precursor, and procedure used (dip-coating or spin-coating) to obtain the film. A bimodal distribution of probe sites in the films was obtained from modeling of the emission decays by a double exponential and from application of the exponential series method. The parameters of the decay components depended principally on the thermal treatment used in the processing of the films. The lifetimes decreased with the increase in the drying temperature of the films; at the same time, the emission spectra showed a red shift and the luminescence efficiency decreased. A luminescence quenching of the ruthenium complex in the films by 4-bromo-2,6-dimethylphenol and 2,6-dimethylphenol in aerated aqueous solution at pH 12 in contact with the film was also observed. The quenching plots obtained from luminescence intensities or luminescence intensity decay measurements showed a downward curvature. These plots could be fitted satisfactorily by a sum of two Stern-Volmer terms with quenching constants K(SV1) and K(SV2) associated with two different binding sites of the ruthenium complex. This result is indicative of the matrix microheterogeneity in the films and is fully consistent with the biexponential nature of the luminescence intensity decay profiles. The Stern-Volmer parameter values for both sites in the films suggest that only a low percentage of the probe is accessible to the quencher and its respective constant K(SV1) is lower than in water.