[Motor vehicles and ultraviolet exposure in Mexico]. / Automóviles y exposición ultravioleta en México.

INTRODUCTION: Sun exposure can cause both acute and chronic lesions of the skin due to ultraviolet (UV) radiation. While driving or traveling inside a vehicle, a person is exposed to this radiation, which can induce or exacerbate certain dermatoses. OBJECTIVE: To determine if the window glasses of commercial vehicles in Mexico can block UV transmission or if the addition of tinted films is necessary. MATERIAL AND METHODS: Sixty models of vehicles manufactured between 1998 and 2011 were randomly selected. UVA and UVB were measured through the windshield and lateral window glasses, and their transmission was calculated compared to ambient UV radiation. Four commercial tinted films were also evaluated for UV transmission. RESULTS: The average UVB transmission from the windshield was 0.01% and 0.9% for UVA. For the driver's and front seat's glasses, UVB transmission was 2% and 16% for UVA. Tinted films transmitted less than 4.5% of UVA, and almost 0% of UVB. CONCLUSIONS: Driving with the vehicle's windows closed eliminates 98% of UVB and 84% of UVA. Therefore, the addition of tinted films provides a marginal benefit in most clinical conditions that manifest photosensibility.

In vitro determination of the chromatic effect of a silver nanoparticles solution linked to the gantrez S-97 copolymer on tooth enamel.

Silver nanoparticles (NNPs), alone or in combination with the bioadhesive Gantrez S-97, have demonstrated their efficacy against Streptococcus mutans; however, it is not known if this combination changes the color of teeth. The aim of this work was to measure the color changes occurring after the use of a Gantrez-NNP combination on enamel tooth blocks. Two study groups were randomly formed: enamel blocks brushed with (a) the Gantrez-NNP combination and (b) conventional toothpaste, for 1 minute once daily for 4 weeks, then rinsed with distilled water and placed in thymol solution. Color changes in the enamel blocks were measured using a Minolta colorimeter CR300. Analysis of mixed models was performed with R 2.10.1 at a 95% confidence level, using the nonlinear mixed effects (NLME) package. The results showed that there were no color changes over time, only a high luminosity equal in both groups. Our study showed that the use of the Gantrez-NNP combination is safe with respect to dental esthetics in the control of S. mutans.

Clinical efficacy of 5% sodium hypochlorite for removal of stains caused by dental fluorosis.

The objective of this study was to evaluate the clinical efficacy of 5% sodium hypochlorite solution for removal of stains caused by dental fluorosis in young patients. A clinical trial involved 33 patients with diffuse opacities on the enamel surfaces of maxillary incisors due to effects of dental fluorosis. The protocol of treatment 3 steps: (1) cleaning and enamel etching with 37% phosphoric acid in order to eliminate the layer that covers the fluorotic enamel surface and allow better penetration of the bleaching agent, (2) application of 5% sodium hypochlorite to remove stains caused by organic material, and (3) filling the opened micro-cavities with a light-cured, composite surface sealant to prevent restaining. The whiteness of the enamel lesions before and after treatment were expressed in L*, a*, and b* color space measurements using a Minolta Chroma Meter CR300. Analysis of parameters of [symbol:see text]E (L*, a*, b*) showed that changes were observed in the L* (brightness) and a* (redness), which paralleled the [symbol: see text]E differences. There was no significant difference in the b* (yellow) parameter. The technique described in this study appears to have advantages over other methods for improving the appearance of fluorotic lesions. It is simple, low cost, non invasive so the enamel keeps its structure, relatively rapid, and safe; it requires no special materials, and it can be used with safety on young permanent teeth.