  
A Functional and Mathematical Comparative Analysis of Abutment-Implant
Interfaces
Kwan, Norman H-K: 206 King Street, St.
Catharines, Ontario, Canada, L2R 3J7
Abstract:
A comparative study was conducted to investigate the stability
of two different abutments and abutment screws in single implant
restoration. Two cemented single crowns, each angulated at 15? to
a 30 kg vertical load and 15? to the implant axis, were fabricated
using: (A) straight abutment with an angulated crown, and (B) straight
crown with an angulated abutment.
A mathematical vector analysis of the two
specimens indicated that arrangement (A) has a torque of 122kg.mm
at the abutment-implant interface, while arrangement (B) has a smaller
torque of 112kg.mm.
In the functional analysis using cyclic fatigue
loading, crown mobility was assessed using PTV values. The endpoint
was defined either when PTV of the crown was greater than 10, or
when the samples reached 20 M cycles. Arrangement (A) typically
ran out well over 20 million cycles while arrangement (B) failed
on average at 2.6 million cycles for the same given load.
The result of this experiment shows that arrangement
(A) is at least 7 times more stable than arrangement (B). This difference
in crown mobility during cyclic fatigue loading is directly related
to the design of the abutment screw and not related to the torque
at the abutment-implant interface or cementation.
Key Words:
Restorative abutment-implant analysis, arrangements,
cyclic fatigue loading, screw integrity, cement loading, circumferential-periphery
gingival proximity of the abutment, single tooth, angulated crown,
angulated abutment, functional comparative analysis.
1. Andersson B, Ödman P, Boss A, Jörnéus
L. Mechanical Testing of Superstructures on the CeraOne Abutment
in the Brånemark System. Int J Oral Maxillofac Implants 1994;
9:665-672.
2. Weinberg LA, Kruger B. A Comparison of
Implant/Prosthesis Loading With Four Clinical Variables. Int J Prosthodont
1995; 8:421-432.
Self supported and supported in part by National Research Council
of Canada # 28048U.
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