with high peel energies is therefore the typical failure mode of amorphous polyolefin.
In many cases, it is stated that a cohesive failure
of the component is wanted.
There are two modes of failure, including adhesive failure and cohesive failure
. Adhesive failure occurs when the mechanical strength of the TPE is greater than the adhesion strength between the TPE and the substrate.
Failure modes were evaluated according to three categories: adhesive failure (no root canal sealer on the dentin surface), cohesive failure
(surface of the dentin was covered with sealer), and mixed failure (cohesive and adhesive failure modes mixture).
Failure analysis showed the predominant failure modes to be cohesive failure
for the Control, CH and TAP groups and adhesive failure for the DAP and mTAP groups (Table-I).
(C) occurred within substrate or repair material, while adhesive failure (A) if it occurred at repair interface.
Furthermore, the cohesive failure
can be found in the substrate or in the preparation of the mortars.
The failure mode changed from cohesive failure
to interfacial failure, and the bond strength continued to degrade with moisture exposure.
Each sample was evaluated at 56 x magnification and put into one of the categories according previous studies : (i) adhesive failure either at the sealer/dentin or between the sealer/core interfaces at the, (ii) cohesive failure
within the filling material, and (iii) mixed failure in both adhesive and cohesive modes.
The cohesive failure
mainly contains two stages, including damage initiation and crack propagation.
When testing on concrete, the pressure in the actuator typically exceeds the internal tensile strength of the concrete itself, at which point a cohesive failure
occurs within the concrete.
in dentin ranged from 5-20 %, and cohesive failure
in composite was only observed in one group (Fig.