Survey
* Your assessment is very important for improving the workof artificial intelligence, which forms the content of this project
* Your assessment is very important for improving the workof artificial intelligence, which forms the content of this project
Journal of the Laser and Health Academy Vol. 2013, No.1; www.laserandhealth.com ISSN 1855-9913 Quality of Restorations Performed with QSP Mode Aslihan Usumez Bezmialem Vakif University Faculty of Dentistry Department of Prosthodontics SUMMARY Er:YAG lasers represent a promising technology with various applications in every field of Dentistry. Compared with other lasers, Er:YAG can effectively alter enamel and dentin surface because of its 2940 nm wavelength emission, which is coincident with the main absorption band of water and OH- groups in hydroxyapatite.[1] Laser irradiation parameters define the exact interaction of the laser on the tissue. Pulse duration is an important factor for the ability of a laser to perform surface modification.[2] Active electronic control of laser pulse duration and amplitude is possible today with the development of Variable Square Pulse® technology (Fotona, Ljubljana, Slovenia). With VSP, the duration of pulses can be adjusted from 50 μs (super-short pulse) to 100 μs (very short pulse), 300 μs (short pulse), 600 μs (long pulse) and 1,000 μs (very long pulse). Because of its higher energy in the shorter pulses, the energy loss through heat is lower. As a result of this, ablation becomes more effective and a thermal effect is not evident on the tissue.[3] The Quantum Square Pulse (QSP) mode has also recently been introduced in Er:YAG laser technology. In QSP mode, each pulse is split into several shorter pulses that follow each other at an optimally fast rate. In this way, absorption and scattering of the laser beam is avoided and undesirable thermal effects for the tissues are decreased.4 Lasers operating at this mode are reported to provide fast and precise hard dental tissue preparation.[5] When the effects of different Er:YAG laser pulse modes (MSP and QSP) on the microleakage of composite resin restoration (Clearfil Majesty Posterior, Kuraray) using a self-etch adhesive systems were evaluated, the cavities etched with Er:YAG laser QSP mode showed less microleakage than MSP mode etched and acid-etched surfaces. The QSP mode is also successful in the etching of enamel surfaces for orthodontic bonding. Er:YAG laser etching with QSP mode presents a successful alternative to acid etching by providing higher or comparable shear bond strength values. The Scanning Electron Microscope (SEM), Atomic Force Microscope (AFM) and surface profilometry utilized in the study demonstrated successful alterations of the enamel surface with this technology (Figure 1-3).[6] Fig. 1: Atomic force microscope scan of an enamel surface etched with 37% phosphoric acid. Fig. 2: Atomic force microscope scan of an enamel surface etched with MSP mode Er:YAG laser. Fig. 3: Atomic force microscope scan of an enamel surface etched with QSP mode Er:YAG laser. To evaluate the microtensile bond strength (μTBS) of a self-etch adhesive to dentin after treatment with Er:YAG laser using different pulse durations and parameters, the dentin surfaces were irradiated with an Er:YAG laser with the following parameters: (1) energy output: 200 mJ or 120 mJ; (2) water cooling: 50 ml/min or 25 ml/min; (3) pulse duration: MSP mode or QSP mode. The Er:YAG laser irradiation increased the μTBS of the adhesive-to-dentin surface when compared S03 with the results of self-etch adhesive alone. Among the Er:YAG laser irradiated surfaces, the highest μTBS result was achieved in the low-energy output and lowwater cooling applied group (Figures 4-7). Fig. 7: SEM view of the interface between dentin etched with QSP mode Er:YAG laser and composite resin. Fig. 4: SEM view of dentin surface etched with MSP mode Er:YAG laser. According to the results of the current studies, it can be concluded that the QSP mode of the Er:YAG laser is a very effective and promising new pulse mode for preparing surfaces for the bonding of resin materials on hard dental tissues. REFERENCES 1. 2. 3. Fig. 5: SEM view of the interface between dentin etched with MSP mode Er:YAG laser and composite resin. 4. 5. 6. Fig. 6: SEM view of dentin surface etched with QSP mode Er:YAG laser. Firat E, Gurgan S, Gutknecht N. Microtensile bond strength of an etch-and-rinse adhesive to enamel and dentin after Er:YAG laser pretreatment with different pulse durations. Lasers Med Sci 2012;27:15-21. Lukac M, Marko M, Ladislav G. Super VSP Er:YAG pulses for fast and precise cavity preparation. J Oral Laser Applic. 2004;4:171–173. Grgurevic J, Grgurevic L, Miletic I, Karlovic Z, Jukic Krmek S, Anic I. In vitro study of the variable square pulse Er:YAG laser cutting efficacy for apicectomy. Lasers Surg Med. 2005;5:347– 350. Gutknecht N, Lukac M, Marincek M, Perhavec T, Kazic M. A Novel Quantum Square Pulse (QSP) Mode Erbium Dental Laser. J LAHA. 2011;1:15-21. Lukac M, Primc NM, Pirnat S. Quantum Square Pulse Er:YAG Lasers for fast and precise hard dental tissue preparation. J LAHA. 2012;1:14-21. Sagır S, Usumez A, Ademci A, Usumez S. Effect of enamel laser irradiation at different pulse settings on shear bond strength of orthodontic brackets, Angle Orthodontics, In press. The intent of this Laser and Health Academy publication is to facilitate an exchange of information on the views, research results, and clinical experiences within the medical laser community. The contents of this publication are the sole responsibility of the authors and may not in any circumstances be regarded as official product information by medical equipment manufacturers. When in doubt, please check with the manufacturers about whether a specific product or application has been approved or cleared to be marketed and sold in your country. S04