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ePaper created 2016-04-05, 13:01:42 | version 1.38.0
| research 16 laser 1 2016 face, creating a chemical bond with the calcium, probably enhancing the adhesion. According to Vi- suri et al., the main presence of peritubular dentin in the dentin surface treated with laser can explain why the SBS was better than that of the Control Group.26 This surface results from a higher content of water in the intertubular dentin, leading to more ablation of this substract.9 The mean of the SBS of the VF in Group 2 (4.76 ± 3.99 MPa) was lower compared to other studies performed by Altunsoy et al., and Yazici et al. in lased dentin with Er:YAG.1, 3 One of the main reasons that could explain this difference is the use Er:YAG laser in these studies, and the different settings applied.1,3 In all samples of Group 3, and in one of Group 2, a gap in the in- terface of the dentin surface and the VF was seen, probably due to thermocycling. According to El-Marhomy et al., the thermocycling influences the marginal gap of composite restorations,27 be- cause the hot water can accelerate the hydrolysis of the interface components and induce stress be- tween the composite and the dental surface.28 De- spite these findings, the effect of thermocycling is still controversial because some studies showed no influence of thermocycling on gap formation.29 One of the objectives of this study was to com- pare the influence of the laser frequency on the SBS of the VF. The results showed that even if you get a smoother surface with the increasing of the laser frequency, as we can see in the SEM micro- graphs, the SBS is lower (0.81 ± 0.93 MPa) com- pared to Group 2 (4.76 ± 3.99 MPa) and Control Group (1.87 ± 1.61 MPa). These results concur with a study performed by Samad-Zadeh et al., in which the authors concluded that the SBS was higher in the laser-textured dentin substrate, with greater spacing patterns.30 Comparing the results of this study with other studiesisalwaysachallengebecausedifferentlasers and parameters influence the laser-tissue inter action, leading to different outcomes. All dental products on the market were produced to work in dental surfaces prepared by conventional methods like the bur. This study and all the studies referred to in this article tested those materials available in the market. The results should be used to develop new products, with a laser-treated dental surface in mind. Conclusion Although the bond strength of the Vertise™ Flow was influenced by the type of dentin surface and the laser parameters, the results of each group were not statistically different between each other (p > 0.05), showing no significant difference con- cerning dentin-surface treatment. The increase of only the laser frequency resulted in lower SBS. Ad- ditional studies should be carried out in order to reach a better adhesion of self-etch flowable com- positesindentinsurfacespreparedwithEr,Cr:YSGG laser, possibly trying new laser settings._ Editorial note: A list of references is available from the publisher. contact Ana Catarina Nogueira da Silva, DMD, MSc Conservative Dentistry Department, Faculdade de Medicina Dentária, Universidade do Porto, Portugal Rua Dr. Manuel Pereira da Silva, 4200–393 Porto, Portugal anacatns@gmail.com Kurz & bündig Selbstklebende, fließfähige Harz-Composites verbinden ein Bondingsystem mit einem fließfähigen Composite. Diese Art Material ist ideal für den Einsatz bei schwierigen Patienten sowie Kindern, da es eine Restauration in wenigen Schrit- ten mit einer kürzeren Behandlungsdauer begünstigt. In der vorliegenden Studie wurde das selbstklebende, fließfähige Harz-Composite Vertise™ Flow (VF) der Firma Kerr verwendet. Das Hauptziel dieser Studie war es, die Bondingstärke des selbstklebenden, fließfähigen Composites Vertise™ Flow an Dentinoberflächen zu ermitteln, welche mithilfe eines Er,Cr:YSGG-Lasers in zwei verschiedenen Voreinstellungen präpariert wurden. Obwohl die Bondingstärke des verwendeten Composites durch die Dentinoberfläche und die Laserparameter beeinflusst wurde, unterschieden sich die Ergebnisse der verschiedenen Versuchsgruppen statistisch nicht voneinander (p > 0.05), sodass kein signifikanter Unterschied hinsichtlich der Behandlung der Dentinoberfläche festgestellt werden konnte. Ein Erhöhen der Laserfrequenz bewirkte eine niedrigere SBS (Shear Bonding Strength). Weitere Studien sollten durchgeführt werden, um eine verbesserte Adhäsion der selbstätzenden, fließfähigen Composites an Dentinoberflächen zu erreichen, welche durch Er,Cr:YSGG-Laser präpariert wurden. Dabei könnten weitere Laser-Einstellungen getestet werden. 12016