Effect of a one-step self-etch adhesive on endogenous dentin matrix metalloproteinases.

Degradation of the hybrid layer created in dentin by dentin adhesives is caused by enzyme activities present within the dentin matrix that destroy unprotected collagen fibrils. The aim of the present study was to evaluate the effect of a one-step self-etch adhesive system on dentinal matrix metalloproteinases 2 and 4 (MMP-2 and MMP-9, respectively) using in situ zymography and an enzymatic activity assay. The null hypothesis tested was that there are no differences in the activities of dentinal MMPs before and after treatment with a one-step adhesive system. The MMP-2 and MMP-9 activities in dentin treated with the one-step adhesive, Adper Easy Bond, were quantified using an enzymatic activity assay system. The MMP activities within the hybrid layer created by the one-step adhesive tested were also evaluated using in situ zymography. The enzymatic assay revealed an increase in MMP-2 and MMP-9 activities after treatment with adhesive. In situ zymography indicated that gelatinolytic activity is present within the hybrid layer created with the one-step self-etch adhesive. The host-derived gelatinases were localized within the hybrid layer and remained active after the bonding procedure. It is concluded that the one-step self-etch adhesive investigated activates endogenous MMP-2 and MMP-9 with the dentin matrix, which may cause collagen degradation over time.

A odontologia adesiva e suas aplicaçöes clínicas / The adehesive dentistry and its clinical applications

Com o advento dos sistemas adesivos e sua rápida evoluçäo, podemos solucionar, de forma simples e rápida, alguns problemas encontrados na clínica diária, proporcionando ao paciente restauraçöes diretas ou indiretas mais conservativas, estéticas, e devido à sua adesäo às estruturas dentais, com menos microinfiltraçäo e consequente cárie secundária. O objetivo deste trabalho é, através da literatura, mostrar as características dos sistemas adesivos, sua evoluçäo e algumas de suas aplicaçöes na odontologia

High incidence of bites and stings by snakes and other animals among rubber tappers and Amazonian Indians of the Juruá Valley, Acre State, Brazil.

Among forest-dwelling Amazonian Indians and rubber tappers (seringueiros) of the Juruá valley in Acre State, north-western Brazil, snakebite is an important cause of morbidity and death. Overall, 13% of a surveyed population had been bitten during their lifetime. Seventeen per cent of Katukina Indians, but only 8% of Ashaninkas, had been bitten by snakes reflecting, perhaps, different levels of traditional knowledge of the forest and its dangers. Most bites occurred in the jungle or on jungle trails (56%), while people were working (41%) or walking (26%), and were inflicted on the feet (54%). Ninety per cent of bite victims received treatment, usually traditional (93%); the majority (80%) recovered fully. Mortality was estimated at about 400 deaths per 100,000 population per lifetime. Bites and stings from other venomous forest and river animals, especially the freshwater sting ray (Potamotrygon sp.), were also extremely common. One death from an ant bite was recorded.