Stress distribution in implant-supported prosthesis with external and internal implant-abutment connections

Objective. This study aimed to investigate the stress distribution in screwed implant-supported prostheses with different implant-abutment connections by using a photoelastic analysis. Materials and methods. Four photoelastic models were fabricated in PL-2 resin and divided according to the implant-abutment connection (external hexagon (EH) and Morse taper (MT) implants (3.75 × 11.5 mm)) and the number crowns (single and 3-unit piece). Models were positioned in a circular polariscope and 100-N axial and oblique (45) loading were applied in the occlusal surface of the crowns by using a universal testing machine. The stresses were photographically recorded and qualitatively analyzed using software (Adobe Photoshop). Results. Under axial loading, the MT implants exhibited a lower number of fringes for single-unit crowns than EH implants, whereas for a 3-unit piece the MT implants showed a higher number of fringes vs EH implants. The oblique loading increased the number of fringes for all groups. Conclusion. In conclusion, the MT implant-abutment connection reduced the amount of stress in single-unit crowns, for 3-unit piece crowns the amount of stress was lower using an external hexagon connection. The stress pattern was similar for all groups. Oblique loading promoted a higher stress concentration than axial loading. © Informa Healthcare.

Las narrativas de la participación social entre los adultos mayores: entre la reciprocidad y la desolación

Incluye Bibliografía

Efficacy of four irrigation needles in cleaning the apical third of root canals

This study aimed to evaluate the influence of irrigation needle gauge and design, and the final root canal diameter on the apical cleaning efficacy. Twelve human mandibular incisors were used. At different stages of root canal widening (sizes 20, 30 and 40 K-files), root canals were filled with radiopaque contrast medium. Four different needles were evaluated: 23G with side opening, 22G with apical opening, 30G with side opening and 30G with apical opening. Irrigation was carried out with 2 mL distilled water. The same tooth was radiographed with a digital system several times to assess the four types of needle in those three stages of canal widening. Pre-irrigation (canals filled with contrast) and post-irrigation (canals with remaining contrast) images were submitted to digital subtraction using the Adobe Photoshop CS4 program. Pre-irrigation (filled with contrast) and subtracted (cleaned by irrigation) areas were outlined by a trained and blinded operator using the Image Tool 3.0 software. Their ratio was calculated to express the percentage of apical cleaning in each stage of canal widening (sizes 20, 30 and 40 K-files) with each of the four needles. Data obtained were subjected to one-way ANOVA and Tukey's tests. The 30G needles with side and apical opening promoted better apical cleaning at all stages of root canal widening (p<0.05). In conclusion, smaller diameter needles were more efficacious in cleaning the apical third of the root canals, regardless of their design.

Stress analysis in oral obturator prostheses: Imaging photoelastic

Maxillary defects resulting from cancer, trauma, and congenital malformation affect the chewing efficiency and retention of dentures in these patients. The use of implant-retained palatal obturator dentures has improved the self-esteem and quality of life of several subjects. We evaluate the stress distribution of implant-retained palatal obturator dentures with different attachment systems by using the photoelastic analysis images. Two photoelastic models of the maxilla with oral-sinus-nasal communication were fabricated. One model received three implants on the left side of the alveolar ridge (incisive, canine, and first molar regions) and the other did not receive implants. Afterwards, a conventional palatal obturator denture (control) and two implant-retained palatal obturator dentures with different attachment systems (O-ring; bar-clip) were constructed. Models were placed in a circular polariscope and a 100-N axial load was applied in three different regions (incisive, canine, and first molar regions) by using a universal testing machine. The results were photographed and analyzed qualitatively using a software (Adobe Photoshop). The bar-clip system exhibited the highest stress concentration followed by the O-ring system and conventional denture (control). Images generated by the photoelastic method help in the oral rehabilitator planning. © 2013 SPIE.

Use of cone-beam tomography and digital subtraction radiography for diagnosis and evaluation of traumatized teeth treated with endodontic surgery and MTA. A case report

The aim of this paper was to report the diagnosis and evaluation of periradicular bone repair by using computed tomography and digital subtraction radiography in an endodontic surgery case treated with mineral trioxide aggregate (MTA). The patient had local swelling and fistula 7years after trauma in the upper jaw. Periapical lesion on tooth #12 and root resorption of tooth #11 were detected radiographically. Endodontic therapy and placement of intracanal medication were carried out. After 3months, with no improvement in the clinical signs and symptoms, computed tomography was performed, showing extensive apical bone resorption on tooth #12 and dental resorption promoting communication of the root canal with the periodontium of tooth #11. The patient was referred to endodontic surgery. After surgery and postoperative periods of 15, 30, 60, 90, and 120days, standardized radiographs were taken, digitized, and subjected to digital subtraction of the images using Adobe Photoshop CS software. Four years later, a cone-beam computed tomography was performed, showing bone repair and absence of root resorption at tooth #11. In this clinical case, digital subtraction radiography was effective for early detection of new bone formation and evolution of repair. © 2011 John Wiley & Sons A/S.

Sistema CIE Lab: análise computacional de fotografias

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Avaliação das alterações radiográficas após tratamento endodôntico de dentes com lesão periapical empregando dois programas de interpretação de imagens

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Análise radiográfica da modelagem de canais radiculares ovalados realizada com sistemas rotatórios de níquel-titânio

Pós-graduação em Odontologia - FOAR

Técnicas empíricas para el asentamiento humano en el trópico húmedo

Incluye Bibliografía

Marine project ideas for the Haitian port of Miragoane: provisional version

Includes bibliography

Jamaica: tamaño de las empresas y remuneración laboral en el sector privado

Los datos sugieren que los mercados laborales no encuentran el equilibrio según la microeconomía tradicional. Las persistentes desigualdades salariales intersectoriales y aquellas derivadas del tamaño de la empresa constituyen un desafío. Los datos del sector privado de Jamaica revelan que las desigualdades salariales según tamaño de la empresa podrían promover desigualdades intersectoriales. Al considerar la calidad de la mano de obra y otras características, se descubre que las empresas con 10 a 49 empleados y aquellas con 50 o más pagan primas estimadas de 14,3% y 22,9%, respectivamente. Tras estimar las diferencias en los perfiles de permanencia laboral, la prima vinculada a empresas mayores se redujo al 15,9%, y no varió la vinculada a empresas con 10 a 49 trabajadores. No obstante la explicación parcial proporcionada por los diferentes perfiles de permanencia laboral, el grueso de las desigualdades salariales según tamaño de la empresa parece obedecer a otras construcciones teóricas.

Análise fotoelástica da tensão entre diferentes tipos de sistemas de retenção em próteses obturadoras palatinas implanto-retidas ou não e com ou sem reembasamento “soft”

Pós-graduação em Odontologia - FOA

Ciudades e infancia: juego, participación y derechos culturales en Rosario (Argentina)

La infancia y la adolescencia son etapas de la vida de los seres humanos a la vez que construcciones socio-históricas cuyas condiciones y abordajes se han ido transformando a lo largo del tiempo. Particularmente, en las últimas décadas han sido objeto de profundas reconceptualizaciones que han impreso un giro a la fundamentación, diseño e implementación de políticas públicas enfocadas en los niños, niñas y adolescentes. Del conjunto de estas políticas se exploran en este documento aquellas dirigidas a promover y garantizar el derecho al juego, la recreación cultural y la participación en la ciudad. Se ha privilegiado, para tal fin, una metodología cualitativa que complementa el análisis de fuentes primarias (entrevistas en profundidad) y secundarias de datos e información. El estudio de caso se realizó en la ciudad de Rosario, Argentina, que tiene un reconocimiento, a nivel nacional e internacional, en materia de gobernabilidad y participación ciudadana así como en la creación de dispositivos innovadores de políticas públicas para las infancias y adolescencias.