Epidemiologia e saúde bucal coletiva: um caminhar compartilhado.

The public health dentistry is a way to bring oral health to Brazilian National Health System (SUS) and vice-versa. Thus, the epidemiology, in this context, it is one of the most important allies. In this article we intend to discuss the "shared walkway" between epidemiology and public health dentistry, through two views: first, we analyzed the efforts to establish methodological models for oral health sectional studies and the possibilities to construct a national data base. Second, we discussed how this knowledge has been transformed in a qualified scientific production presented in meetings and papers, which reflects, at the same time, about the contribution of this process in the consolidation of public health dentistry field. We concluded that this "shared walkway" was (and still is), influenced by political aspects, which, in different moments, leads to an improvement of public health dentistry. The oral health epidemiology has been established as a knowledge area, with regard to the scientific production in Brazil. At the same time, provide a tool that contributes to make oral health care models more appropriate to National Health System principles and, in other hand, make better the discussions about the social determinants of oral diseases.

Epidemiologia e saúde bucal coletiva: um caminhar compartilhado.

The public health dentistry is a way to bring oral health to Brazilian National Health System (SUS) and vice-versa. Thus, the epidemiology, in this context, it is one of the most important allies. In this article we intend to discuss the "shared walkway" between epidemiology and public health dentistry, through two views: first, we analyzed the efforts to establish methodological models for oral health sectional studies and the possibilities to construct a national data base. Second, we discussed how this knowledge has been transformed in a qualified scientific production presented in meetings and papers, which reflects, at the same time, about the contribution of this process in the consolidation of public health dentistry field. We concluded that this "shared walkway" was (and still is), influenced by political aspects, which, in different moments, leads to an improvement of public health dentistry. The oral health epidemiology has been established as a knowledge area, with regard to the scientific production in Brazil. At the same time, provide a tool that contributes to make oral health care models more appropriate to National Health System principles and, in other hand, make better the discussions about the social determinants of oral diseases.

The Effect of Residence Time on the Tensile Properties of Superelastic and Thermal Activated Ni-Ti Orthodontic Wires

Since the 1980s, different devices based on superelastic alloys have been developed to fulfill orthodontic applications. Particularly in the last decades several researches have been carried out to evaluate the mechanical behavior of Ni-Ti alloys, including their tensile, torsion and fatigue properties. However, studies regarding the dependence of elastic properties on residence time of Ni-Ti wires in the oral cavity are scarce. Such approach is essential since metallic alloys are submitted to mechanical stresses during orthodontic treatment as well as pH and temperature fluctuations. The goal of the present contribution is to provide elastic stress-strain results to guide the orthodontic choice between martensitic thermal activated and austenitic superelastic Ni-Ti alloys. From the point of view of an orthodontist, the selection of appropriate materials and the correct maintenance of the orthodontic apparatus are essential needs during clinical treatment. The present work evaluated the elastic behavior of Ni-Ti alloy wires with diameters varying from 0.014 to 0.020 inches, submitted to hysteresis tensile tests with 8% strain. Tensile tests were performed after periods of use of 1, 2 and 3 months in the oral cavity of patients submitted to orthodontic treatment. The results from the hysteresis tests allowed to exam the strain range covered by isostress lines upon loading and unloading, as well as the residual strain after unloading for both superelastic and thermal activated Ni-Ti wires. Superelastic Ni-Ti wires exhibited higher load isostress values compared to thermal activated wires. It was found that such differences in the load isostress values can increase with increasing residence time.

The Effect of Residence Time on the Tensile Properties of Superelastic and Thermal Activated Ni-Ti Orthodontic Wires

Since the 1980s, different devices based on superelastic alloys have been developed to fulfill orthodontic applications. Particularly in the last decades several researches have been carried out to evaluate the mechanical behavior of Ni-Ti alloys, including their tensile, torsion and fatigue properties. However, studies regarding the dependence of elastic properties on residence time of Ni-Ti wires in the oral cavity are scarce. Such approach is essential since metallic alloys are submitted to mechanical stresses during orthodontic treatment as well as pH and temperature fluctuations. The goal of the present contribution is to provide elastic stress-strain results to guide the orthodontic choice between martensitic thermal activated and austenitic superelastic Ni-Ti alloys. From the point of view of an orthodontist, the selection of appropriate materials and the correct maintenance of the orthodontic apparatus are essential needs during clinical treatment. The present work evaluated the elastic behavior of Ni-Ti alloy wires with diameters varying from 0.014 to 0.020 inches, submitted to hysteresis tensile tests with 8% strain. Tensile tests were performed after periods of use of 1, 2 and 3 months in the oral cavity of patients submitted to orthodontic treatment. The results from the hysteresis tests allowed to exam the strain range covered by isostress lines upon loading and unloading, as well as the residual strain after unloading for both superelastic and thermal activated Ni-Ti wires. Superelastic Ni-Ti wires exhibited higher load isostress values compared to thermal activated wires. It was found that such differences in the load isostress values can increase with increasing residence time.