Abstract
Statement of problem
Evidence for the optimal spatial arrangement of magnetic attachments in implant-supported
orbital prostheses is lacking.
Purpose
The purpose of this in vitro study was to assess the effect of 6 different spatial
arrangements on the retentive force of magnetic attachments following the in vitro
simulation of clinical service by insertion-removal test cycles and the contribution
of artificial aging to the morphological alterations induced on the magnetic surfaces.
Material and methods
Ni-Cu-Ni plated disk-shaped neodymium (Nd) magnetic units (d=5 mm, h=1.6 mm) were
secured on leveled (50×50×5 mm, n=3) and angled (40×45×40 mm, interior angle=90 degrees,
n=3) pairs of test panels in 6 different spatial arrangements: triangular_leveled
(TL), triangular_angled (TA), square_leveled (SL), square_angled (SA), circular_leveled
(CL), and circular_angled (CA) generating corresponding test assemblies (N=6). TL
and TA arrangements included 3 magnetic units (3-magnet groups) and SL, SA, CL, and
CA 4 (4-magnet groups). The retentive force (N) was measured at a mean crosshead speed
of 10 mm/min (n=10). Each test assembly was subjected to insertion-removal test cycles
with a 9-mm amplitude, ν=0.1 Hz, and n=10 consequent retentive force measurements
at a crosshead speed of 10 mm/min at 540, 1080, 1620, and 2160 test cycles. Surface
roughness alterations following the 2160 test cycles were measured by calculating
the Sa, Sz, Sq, Sdr, Sc, and Sv parameters with an optical interferometric profiler
with 5 new magnetic units used as a control group. Data were analyzed with 1-way ANOVA
and Tukey HSD post hoc tests (α=.05).
Results
The 4-magnet groups had statistically significantly higher retentive force than the
3-magnet ones at baseline and following the 2160 test cycles (P<.05). In the 4-magnet group, the ranking at baseline was SA<CA<CL<SL (P<.05) and following the test cycles SA=CA<CL<SL (P<.05). No statistically significant differences were found in the surface roughness
parameters (Sa, Sz, Sq, Sdr, Sc, and Sv) following the 2160 test cycles among the
experimental groups tested (P>.05).
Conclusions
Four magnetic attachments placed on an SL spatial arrangement resulted in the highest
retention force but presented with the highest force reduction following the in vitro
simulation of clinical service by insertion-removal test cycles.
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Article info
Publication history
Published online: March 06, 2023
Publication stage
In Press Corrected ProofFootnotes
This study was funded by The University of Texas, M.D. Anderson Cancer Center.
Identification
Copyright
© 2023 by the Editorial Council for the Journal of Prosthetic Dentistry.
