Ao fim da vida, o corpo passa por um processo natural de decomposição onde sua matéria é transfor... more Ao fim da vida, o corpo passa por um processo natural de decomposição onde sua matéria é transformada por bactérias e enzimas em sais, líquidos e gases. Esses efluentes da decomposição cadavérica são potenciais poluidores do meio ambiente que acabam transformando os cemitérios em centros de contaminação constante através de mudanças biológicas, físicas e químicas ao solo, ar e principalmente os recursos hídricos próximos. Estudos bibliométricos fornecem um meio útil para rastrear as pesquisas e tendências em uma determinada área. Para isso, foi realizado um estudo bibliométrico das publicações sobre esse tema publicadas na última década disponíveis nos bancos de dados Web of Science e Scopus. A partir dos trabalhos abordados é possível compreender como a contaminação dos efluentes cadavéricos ocorre, através da retenção e tratamento desses resíduos é possível contornar esse problema, sendo os cemitérios verticais os mais indicados pois facilitam a coleta dos efluentes. Soluções viá...
A variety of techniques can be used to achieve stabilization of femoral valgus osteotomies in chi... more A variety of techniques can be used to achieve stabilization of femoral valgus osteotomies in children, but what is lacking is a versatile fixation system that associates stability and versatility at different ages and for different degrees of deformity. Mechanical tests of three configurations used to fix femoral valgus osteotomies, based on the tension band wire principle, were carried out. A 30 degrees wedge valgus osteotomy was performed at the subtrochanteric level in 60 swine femurs and fixed with three different systems. In Group 1, two Kirschner wires (K wire) were introduced from the tip of the greater trochanter to the medial cortex, crossing the osteotomy. A flexible steel wire was anchored to the K wires into holes in the lateral cortex and tightened to form a tension band. The same setup was used in Group 2, but two additional smooth K wires were inserted into the lateral surface of the greater trochanter and driven to the femoral head with the distal extremities bent and tied around the bone shaft. In Group 3, the fixation was similar to that in Group 2, but the ascending K wires were introduced below the osteotomy level, crossing the osteotomy. Mechanical tests in bending-compression and torsion were used to access the stability. The torsional relative stiffness was 116% greater for Group 3 (0.27 Nm/degree) and no significant difference was found between Group 1 (0.10Nm/degree) and Group 2 (0.12 Nm/degree). The average torque was 103% higher for Group 3 (1.86 Nm). Stiffness in bending-compression was significantly higher in Group 3 (508 x 10(3) N/m) than in Group 1 (211 x 10(3) N/m) and Group 2 (219 x 10(3) N/m). Fixation as used in Group 3 was significantly more stable, both in torsion and bending-compression tests, than the other two techniques.
Frequent maintenance because of the limited lifetime of overdenture attachments with O-rings has ... more Frequent maintenance because of the limited lifetime of overdenture attachments with O-rings has led to the development of materials that might improve their functionality and longevity. However, testing of newly developed attachment materials is lacking. The purpose of this in vitro study was to evaluate a newly developed attachment made of polyetheretherketone (PEEK) for an implant-retained overdenture. Specimens of PEEK, polyacetal, and Teflon O-ring materials were prepared for analysis of roughness, surface hardness, and compressive strength. For the fatigue resistance test, new specimens based on acrylic resin were subjected to 2880 insertion and removal cycles. Compression and roughness data were compared with the Kruskal-Wallis and Dunn post hoc test; hardness data with ANOVA and t test; and fatigue and stereomicroscopy with ANOVA with repeated measures, t test, and Bonferroni adjustment (α=.05). Polyacetal had the lowest surface roughness (P=.038). There was a significant difference in hardness among the materials (P<.05). PEEK presented the highest compressive strength among the materials (P<.001). For the fatigue resistance, only polyacetal showed a difference between the initial time-point (P<.05) and subsequent time-points. Polyacetal had a higher fatigue resistance than Teflon (P<.001) and PEEK (P<.05). Regarding the internal deformation of the attachments, a significant difference was observed among the materials (P<.05). PEEK showed promising results regarding the physicomechanical properties necessary for use as an overdenture attachment when compared with other evaluated materials. In addition, the PEEK attachment showed results comparable to those in the control group (O-rings) in terms of retention.
Ao fim da vida, o corpo passa por um processo natural de decomposição onde sua matéria é transfor... more Ao fim da vida, o corpo passa por um processo natural de decomposição onde sua matéria é transformada por bactérias e enzimas em sais, líquidos e gases. Esses efluentes da decomposição cadavérica são potenciais poluidores do meio ambiente que acabam transformando os cemitérios em centros de contaminação constante através de mudanças biológicas, físicas e químicas ao solo, ar e principalmente os recursos hídricos próximos. Estudos bibliométricos fornecem um meio útil para rastrear as pesquisas e tendências em uma determinada área. Para isso, foi realizado um estudo bibliométrico das publicações sobre esse tema publicadas na última década disponíveis nos bancos de dados Web of Science e Scopus. A partir dos trabalhos abordados é possível compreender como a contaminação dos efluentes cadavéricos ocorre, através da retenção e tratamento desses resíduos é possível contornar esse problema, sendo os cemitérios verticais os mais indicados pois facilitam a coleta dos efluentes. Soluções viá...
A variety of techniques can be used to achieve stabilization of femoral valgus osteotomies in chi... more A variety of techniques can be used to achieve stabilization of femoral valgus osteotomies in children, but what is lacking is a versatile fixation system that associates stability and versatility at different ages and for different degrees of deformity. Mechanical tests of three configurations used to fix femoral valgus osteotomies, based on the tension band wire principle, were carried out. A 30 degrees wedge valgus osteotomy was performed at the subtrochanteric level in 60 swine femurs and fixed with three different systems. In Group 1, two Kirschner wires (K wire) were introduced from the tip of the greater trochanter to the medial cortex, crossing the osteotomy. A flexible steel wire was anchored to the K wires into holes in the lateral cortex and tightened to form a tension band. The same setup was used in Group 2, but two additional smooth K wires were inserted into the lateral surface of the greater trochanter and driven to the femoral head with the distal extremities bent and tied around the bone shaft. In Group 3, the fixation was similar to that in Group 2, but the ascending K wires were introduced below the osteotomy level, crossing the osteotomy. Mechanical tests in bending-compression and torsion were used to access the stability. The torsional relative stiffness was 116% greater for Group 3 (0.27 Nm/degree) and no significant difference was found between Group 1 (0.10Nm/degree) and Group 2 (0.12 Nm/degree). The average torque was 103% higher for Group 3 (1.86 Nm). Stiffness in bending-compression was significantly higher in Group 3 (508 x 10(3) N/m) than in Group 1 (211 x 10(3) N/m) and Group 2 (219 x 10(3) N/m). Fixation as used in Group 3 was significantly more stable, both in torsion and bending-compression tests, than the other two techniques.
Frequent maintenance because of the limited lifetime of overdenture attachments with O-rings has ... more Frequent maintenance because of the limited lifetime of overdenture attachments with O-rings has led to the development of materials that might improve their functionality and longevity. However, testing of newly developed attachment materials is lacking. The purpose of this in vitro study was to evaluate a newly developed attachment made of polyetheretherketone (PEEK) for an implant-retained overdenture. Specimens of PEEK, polyacetal, and Teflon O-ring materials were prepared for analysis of roughness, surface hardness, and compressive strength. For the fatigue resistance test, new specimens based on acrylic resin were subjected to 2880 insertion and removal cycles. Compression and roughness data were compared with the Kruskal-Wallis and Dunn post hoc test; hardness data with ANOVA and t test; and fatigue and stereomicroscopy with ANOVA with repeated measures, t test, and Bonferroni adjustment (α=.05). Polyacetal had the lowest surface roughness (P=.038). There was a significant difference in hardness among the materials (P<.05). PEEK presented the highest compressive strength among the materials (P<.001). For the fatigue resistance, only polyacetal showed a difference between the initial time-point (P<.05) and subsequent time-points. Polyacetal had a higher fatigue resistance than Teflon (P<.001) and PEEK (P<.05). Regarding the internal deformation of the attachments, a significant difference was observed among the materials (P<.05). PEEK showed promising results regarding the physicomechanical properties necessary for use as an overdenture attachment when compared with other evaluated materials. In addition, the PEEK attachment showed results comparable to those in the control group (O-rings) in terms of retention.
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