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1.
Journal of Dental Rehabilitation and Applied Science ; : 189-198, 2017.
Artículo en Coreano | WPRIM | ID: wpr-169122

RESUMEN

PURPOSE: This study aims to analyze the stress distribution of mandibular molar restoration supported by the implants with external hex and internal taper abutment connection design. MATERIALS AND METHODS: Models of external connection (EXHEX) and internal connection (INCON) implants, corresponding abutment/crowns, and screws were developed. Supporting edentulous mandibular bony structures were designed. All the components were assembled and a finite element analysis was performed to predict the magnitude and pattern of stresses generated by occlusal loading. A total of 120 N static force was applied both by axial (L1) and oblique (L2) direction. RESULTS: Peak von Mises stresses produced in the implants by L2 load produced 6 – 15 times greater than those by L1 load. The INCON model showed 2.2 times greater total amount of crown cusp deflection than the EXHEX model. Fastening screw in EXHEX model and upside margin of implant fixture in INCON model generated the peak von Mises stresses by oblique occlusal force. EXHEX model and INCON model showed the similar opening gap between abutment and fixture, but intimate sealing inside the contact interface was maintained in INCON model. CONCLUSION: Oblique force produced grater magnitudes of deflection and stress than those by axial force. The maximum stress area at the implant was different between the INCON and EXHEX models.


Asunto(s)
Fuerza de la Mordida , Coronas , Análisis de Elementos Finitos , Diente Molar
2.
Braz. dent. j ; 25(1): 48-53, Jan-Feb/2014. tab, graf
Artículo en Inglés | LILACS | ID: lil-709407

RESUMEN

The objective of this study was to evaluate the bacterial seal at the implant-abutment interface using two morse taper implant models, by means of an in vitro microbiological analysis. For that were used 15 implants with mini-abutments tightened by friction, no screws (Group 1); and 30 implants with screw-tightened abutments, of which 15 received 20 N.cm of closing torque (Group 2) and the other 15 received 30 N.cm (Group 3). Microbiological analysis was carried out using colonies of Escherichia coli transported directly from a culture dish to the prosthetic component. Friction implants (Group 1) were activated by tapping and a torque wrench was used for screw-tightened implants (Groups 2 and 3). Each abutment/implant set was immersed in test tubes containing 5 mL of brain-heart infusion broth and incubated at 37 °C for 14 days, observed daily for the presence of contamination. A statistically significant difference was observed regarding the number of contaminated implants. There was greater contamination in Group 2 implants (p<0.05), with no statistically significant difference between the other groups (Group 1 = 20% and Group 3 = 0%). It was concluded that there was no significant difference in in vitro bacterial sealing between implants with mini-abutments tightened by friction without screws and implants with screw-tightened abutments with 30 N.cm of closing torque. The difference in closing torque altered the in vitro sealing ability of the tested abutments, with a greater contamination for components that received a closing torque of 20 N.cm.


O objetivo deste estudo foi avaliar comparativamente, por meio de análise microbiológica in vitro, a capacidade de selamento bacteriano de dois modelos de implante de encaixe morse. Foram utilizados 15 implantes com travamento de seus respectivos mini-pilares por fricção, sem auxílio de parafuso (Grupo 1) e 30 implantes com travamento de seus respectivos mini-pilares sólidos reforçado pela presença de parafuso, sendo que 15 destes implantes receberam torque de inserção de 20 N.cm (Grupo 2) e o restante 30 N.cm (Grupo 3). A análise microbiológica foi realizada utilizando colônias de Escherichia coli transportadas diretamente da placa de cultivo para o componente protético. Os implantes friccionais (Grupo 1) foram ativados por meio do dispositivo bate conexão e para os aparafusados foi usada a chave de torque (Grupos 2 e 3). Cada conjunto de pilar/implante foi imerso em tubos de ensaio contendo 5 mL de caldo BHI (Brain-Heart Infusion) e incubados a 37 °C durante 14 dias com verificação diária de presença de contaminação. Foi observada diferença estatisticamente significante, com relação ao número de implantes contaminados. Para os implantes do Grupo 2, houve maior contaminação (60%, p<0,05), não sendo observada diferença significativa entre os outros grupos (Grupo 1 = 20% e Grupo 3 = 0%). Conclui-se neste estudo que não houve diferença estatística significante quanto ao selamento bacteriano in vitro entre os Grupos 1 e 3. A diferença de torque de inserção alterou a capacidade de selamento in vitro dos pilares testados, sendo observada uma maior contaminação para os componentes que receberam o torque de 20 N.cm.


Asunto(s)
Implantes Dentales , Escherichia coli/aislamiento & purificación , Modelos Biológicos , Medios de Cultivo , Técnicas In Vitro
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