Summary:
Finishing and polishing of direct and indirect restorations in the oral cavity
constitutes the last step of a routine clinical procedure in daily practice.
This step influences both esthetics and longevity of resin composite
restorations. In order to reduce cost, clinical time and simplify the
procedure, single-step finishing/polishing systems were recently introduced to
the dental profession.
The purpose of this study was to evaluate the effect of sterilization on the
performance of four different single-step polishing systems.
The polishing systems evaluated were: Optrapol Next Generation
(Ivoclar/Vivadent), Jazz Supreme (SS White), Optishine (Kerr) and Jiffy
(Ultradent). The resin composite used was IPS Empress Direct
(Ivoclar/Vivadent). All polishing instruments (10 from each polishing system,
40 instruments in total) were initially observed under optical microscope
(magnification 1,6x). Afterwards they were applied in 40 specimens of resin
composite and subsequently sterilized in autoclave at 134C for 20 minutes. All
instruments were re-examined after sterilization under optical microscope.
After polishing, the resin surfaces were immediately examined under optical
profilometer (Sa, Sz, Sdr, Sci) and under glossmeter to determine their gloss.
The 40 instruments were subjected to sterilization and application on a new
resin specimen for 4 subsequent cycles. A total of 200 resin specimens were
constructed. The reference point was each instrument’s first use.
The statistical analysis performed, in order to examine the polishing
performance of polishing systems after the sterilization procedure, was
Friedman test και post-hoc Wilcoxon test (a=0.05).
According to our findings, the performance of Optrapol Next Generation after
the first sterilization was improved, whereas, it declined after the fourth
sterilization cycle. Relevant changes were not noticed for the surface gloss.
The performance of Jazz Supreme was improved after the second and third 97
sterilization cycle. This improvement was statistically significant and was
noticed for both the surface roughness and surface gloss. An improvement of the
polishing performance of Optishine was observed after the second and third
sterilization cycle, which was statistically significant only for surface
gloss. However, the polishing performance declined after the fourth cycle of
sterilization. For Jiffy, the polishing performance was not credible, although
it was affected by performance loss after the fourth sterilization cycle.
Changes of shape of all instruments were observed under the optical microscope
as a result of sterilization cycles.
Summarizing, our results indicate that the performance of all polishing systems
was improved following the first sterilization cycle, while it diminished after
the fourth use. The performance of Jifffy polishing system for the subsequent
sterilization cycles proved to be non-credible, however the inclusion of more
samples could lead to more conclusive results. A noteworthy fact remains that
Sa values for all polishing systems and measurements undertaken did not surpass
0,28μm, the crucial value indicating a adequately smooth surface.
Keywords:
Finishing, Polishing, Resin Composites, Sterilization