TY - JOUR
T1 - Biomechanical evaluation of internal and external hexagon platform switched implant-abutment connections
T2 - An in vitro laboratory and three-dimensional finite element analysis
AU - Freitas-Júnior, Amilcar C.
AU - Rocha, Eduardo P.
AU - Bonfante, Estevam A.
AU - Almeida, Erika O.
AU - Anchieta, Rodolfo B.
AU - Martini, Ana P.
AU - Assunão, Wirley G.
AU - Silva, Nelson R.F.A.
AU - Coelho, Paulo G.
N1 - Funding Information:
This investigation was supported in part by Research Grant 141870/2008–7 from CNPq – Brazil . The authors are thankful to Marotta Dental Studio (Farmingdale, NY, USA) and SIN implants (São Paulo, SP, Brazil) for their support.
PY - 2012/10
Y1 - 2012/10
N2 - Objectives: The aim of this study was to assess the effect of abutment's diameter shifting on reliability and stress distribution within the implant-abutment connection for internal and external hexagon implants. The postulated hypothesis was that platform-switched implants would result in increased stress concentration within the implant-abutment connection, leading to the systems' lower reliability. Methods: Eighty-four implants were divided in four groups (n = 21): REG-EH and SWT-EH (regular and switched-platform implants with external connection, respectively); REG-IH and SWT-IH (regular and switched-platform implants with internal connection, respectively). The corresponding abutments were screwed to the implants and standardized maxillary central incisor metal crowns were cemented and subjected to step-stress accelerated life testing. Use-level probability Weibull curves and reliability were calculated. Four finite element models reproducing the characteristics of specimens used in laboratory testing were created. The models were full constrained on the bottom and lateral surface of the cylinder of acrylic resin and one 30°off-axis load (300 N) was applied on the lingual side of the crown (close to the incisal edge) in order to evaluate the stress distribution (s vM) within the implant-abutment complex. Results: The Beta values for groups SWT-EH (1.31), REG-EH (1.55), SWT-IH (1.83) and REG-IH (1.82) indicated that fatigue accelerated the failure of all groups. The higher levels of σ vM within the implant-abutment connection observed for platform-switched implants (groups SWT-EH and SWT-IH) were in agreement with the lower reliability observed for the external hex implants, but not for the internal hex implants. The reliability 90% confidence intervals (50,000 cycles at 300 N) were 0.53(0.33-0.70), 0.93(0.80-0.97), 0.99(0.93-0.99) and 0.99(0.99-1.00), for the SWT-EH, REG-EH, SWT-IH, and REH-IH, respectively. Significance: The postulated hypothesis was partially accepted. The higher levels of stress observed within implant-abutment connection when reducing abutment diameter (cross-sectional area) resulted in lower reliability for external hex implants, but not for internal hex implants.
AB - Objectives: The aim of this study was to assess the effect of abutment's diameter shifting on reliability and stress distribution within the implant-abutment connection for internal and external hexagon implants. The postulated hypothesis was that platform-switched implants would result in increased stress concentration within the implant-abutment connection, leading to the systems' lower reliability. Methods: Eighty-four implants were divided in four groups (n = 21): REG-EH and SWT-EH (regular and switched-platform implants with external connection, respectively); REG-IH and SWT-IH (regular and switched-platform implants with internal connection, respectively). The corresponding abutments were screwed to the implants and standardized maxillary central incisor metal crowns were cemented and subjected to step-stress accelerated life testing. Use-level probability Weibull curves and reliability were calculated. Four finite element models reproducing the characteristics of specimens used in laboratory testing were created. The models were full constrained on the bottom and lateral surface of the cylinder of acrylic resin and one 30°off-axis load (300 N) was applied on the lingual side of the crown (close to the incisal edge) in order to evaluate the stress distribution (s vM) within the implant-abutment complex. Results: The Beta values for groups SWT-EH (1.31), REG-EH (1.55), SWT-IH (1.83) and REG-IH (1.82) indicated that fatigue accelerated the failure of all groups. The higher levels of σ vM within the implant-abutment connection observed for platform-switched implants (groups SWT-EH and SWT-IH) were in agreement with the lower reliability observed for the external hex implants, but not for the internal hex implants. The reliability 90% confidence intervals (50,000 cycles at 300 N) were 0.53(0.33-0.70), 0.93(0.80-0.97), 0.99(0.93-0.99) and 0.99(0.99-1.00), for the SWT-EH, REG-EH, SWT-IH, and REH-IH, respectively. Significance: The postulated hypothesis was partially accepted. The higher levels of stress observed within implant-abutment connection when reducing abutment diameter (cross-sectional area) resulted in lower reliability for external hex implants, but not for internal hex implants.
KW - Biomechanics
KW - Dental implants
KW - Finite element analysis
KW - Platform switching
KW - Reliability
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U2 - 10.1016/j.dental.2012.05.004
DO - 10.1016/j.dental.2012.05.004
M3 - Article
C2 - 22682782
AN - SCOPUS:84865770427
SN - 0109-5641
VL - 28
SP - e218-e228
JO - Dental Materials
JF - Dental Materials
IS - 10
ER -