Page 180 - Clinical relevance of current materials for cranial implants

Chapter 9
(3)
where Pmax is the maximum load exerted on the specimen [N], ht is the height and bt is the width of the specimen [mm], lt is the span [mm] and f is a geometrical function, dependent on x in Equation 4, where a is the crack length consisting of the notch and the pre-crack [mm].
; (4) The total fracture work, Wf, in J/m2 was calculated using Equation 5.
(5)
where a, ht and bt are the same as for Equation 3. U [N mm] is the area under the load/displacement curve that is defined by Equation 6.
(6)
Unnotched Charpy impact strength
Eighteen series of ten rectangular specimens (62.0 ± 1.0 × 6.0 ± 0.2 × 4.0 ± 0.2 mm), one per material and sterilization method, were produced. The specimens were placed in a Karl Frank 53301 testing machine with a supporting bars span of 50.0 mm and a pendulum energy of 0.5 J for Vertex Self-Curing and Palacos R+G, and 1.0 J for NextDent C&B MFH. The Charpy impact strength, acU, was calculated in kJ/m2 with Equation 7.
(7) where Ec is the corrected energy absorbed by breaking the test specimens [J], h is
the height and b is the width of the specimen [mm].
Data were statistically analyzed using one-way analysis of variance (ANOVA) followed by Tuckey’s post hoc test (α = 0.05) in SPSS version 24.0 (IBM, Armonk, NY, USA).
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