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ePaper created 2016-07-29, 16:53:04 | version 1.38.0
| industry 24 laser 2 2016 Fig. 8 3. In addition to the primary cavitation, secondary cavitation processes are caused by the formation of subsequent, smaller bubbles (Fig. 7).61 Theselaser-inducedeffectsdependontheabsorp- tion spectrum of the endodontic irrigation medium. Thatmeans:Thebetteracertainmediumabsorbsthe laserradiation,thebetteristheprimaryandthe secondary cavitation effect. NaClO 5.3 %, EDTA 17 % and water have almost the same absorption spectrum.62 Wavelengths that are badly absorbed by the irrigation fluid may cause damage totherootcanalwalls,dentinaltubules,or even the periodontal ligament. This is one of the key differences between the two erbium wavelengths. The absorption co- efficient of Er:YAG at 2,940 nm is almost twice as high as that of Er,Cr:YSGG. The PIPS® system operates exclusively at the wavelength of Er:YAG of 2,940 nm. The PIPS® tip design is also a key influ- ence on the effectiveness of cleaning: It is a9 mmlongtipwithadiameterof600 µm, theapical3 mmofwhicharenotsheathed with polyamide and have a tapered end (Fig. 6). The lacking sheath of the apical 3 mm results in better lateral emission. The tip is connectedtothelasersource(LightWalker®,Fotona, Slovenia) via a special endo dontic handpiece. The free axial flexibility facilitates the application even in difficult anatomic situations (Fig. 8). The manufacturer recommends the fol- lowing settings for PIPS®: 50 µS pulse length, 10 to 20 Hz and 0.15 to 0.5 W, i.e. peak powers of 400 W up to 1,000 W are achieved with each pulse due to the inter- action with irrigation fluid. Air/water spray is not required. These settings triggered theshockwavesandthestrongcurrentof irrigation fluid as described above.63 The temperature of the root surface increased by only 1.5 °C with the PIPS® activated for 20 to 40 s.64 Clinical application should follow the manufacturer’s instructions. Attheendofthepreparation,irrigation with 17 % EDTA is performed to remove thesmearlayer.Thepulpcavityshouldbe flooded with EDTA. Then the PIPS® tip is inserted into the orifice and activated for 30seconds(Fig.9).Afterrinsinginterme- diately with saline solution, rinsing with NaClOisperformed.Thisisfollowedbyac- tivating the NaClO twice for 30 seconds respectively with a break of 30 seconds between the intervals. A sufficient quan- tity of fluid in the orifice is important in thisprocedure.Ifnecessary,theassistant needstoaddirrigationfluidcontinuously. The research results regarding PIPS® so far have been promising. One study compared the bacterial reduction as well as the biofilm removal between PUI and PIPS® in vitro. The application of PIPS® re- sulted in the reduction of bacterial contamination by 99.5 %, the significantly better reduction of bio- film, and the significantly greater number of sam- ples that are free from bacteria.65 In another study, Jaramilloetal.comparedtheremovabilityofbiofilm applying various techniques to activate the irriga- tion.BesidesPIPS®(LightWalker®,Fotona,Slovenia), these were the passive ultrasonic irrigation (PUI) and sonic activation (EndoActivator). The laser-in- duced irrigation with PIPS® was significantly supe- rior to all other techniques as regards removing the biofilm (Fig. 10).66 Another study deals with the re- movability of calcium hydroxide from root canals. The authors compared as well PIPS®, PUI, and sonic activation of irrigation fluids. After the laser-acti- vatedirrigationwithPIPS®,allthesampleswerefree from calcium hydroxide, 24 per cent still showed residues in case of PUI.67 The removal of E. faecalis from artificially infected root canals using PIPS® and the sole irrigation with saline solution without activation was the subject matter of another study. Theremarkableresultofthisstudywasthecomplete removal of E. faecalis from all canals in the PIPS® group, in which the preparation was effected only to the Pro Taper® F1 file.68 This study may be an in- Fig. 9 Fig. 8: Fotona LightWalker® and PIPS® handpiece. Fig. 9: PIPS® tip in orifice. 22016