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exhibitors18 Pacific Dental Conference — March 6, 2014 n Successful endodontic treatment depends upon maximal debridement and disinfection of the entire root canal system. The root canal system must be shaped to a convenience form that per- mits adequate cleaning and disinfection byeliminationofmicrobes.1 The literature is clear that as much as 35 percent or more of the root canal systemremainsuntouchedbyanyinstru- mentationtechnique.Essentiallynofiling techniqueallowsinstrumentstosculptall canal walls and remove infected dentin.2 Todecreasethebacterialloadandachieve better debridement, irrigation protocols areusedpriortoobturation. The efficacy of the irrigants to decon- taminatecanalwallshasseensignificant improvements recently. Both negative and positive apical pressure irrigation techniques have been surpassed by ultrasonically activated irrigants, photo- activateddisinfectionandlaser-activated irrigantsintheirabilitytoimproveclean- linessofthecanalsystem.3,4 In particular, the Er:YAG (Lightwalker Er:YAG& Nd:YAG dental laser, National Dental Inc. Barrie, Ontario) has shown to be effective at removing debris and the smear layer from canal walls.3,4 A final application of the Er:YAG laser to the sodium hypochlorite already present within the canal, after standardized instrumentation, can result in improved cleaning of the canal walls with a higher quantityofopentubules(Fig.1)compared withresultswithouttheuseofthelaser.3,4 A new application of Laser-Activated Irrigation (LAI) has been recently intro- duced. Photon Induced Photoacoustic Streaming (PIPS™) uses an Erbium 2,940 lasertopulseextremelylowenergylevels of laser light to generate a photoacous- tic shockwave, which streams irrigants throughouttheentirerootcanalsystem.5 Using extremely short bursts of peak power, laser energy is directed down into the canal and the action actively pumps the tissue debris out of the canals while cleaning, disinfecting and steril- izing each main canal, lateral canals, dentinal tubules and canal anastomoses to the apex. This movement of irrigant is achieved without the need to place the radialandstrippedlasertip(PIPStip,Fig. 2) into the canal itself, as with other con- ventionalhandandultrasonicsystems. Thetipisheldstationaryinthecoronal aspect of the access preparation only. With the irrigant occupying the entire root canal system, the shock wave cre- ated by PIPS travels in all directions dur- ing activation and effectively debrides and removes organic tissue remnants. Through this laser-activated turbulent flow phenomenon, clinicians following the PIPS protocol are not required to place the tip into each canal, thus elim- inating the need to enlarge and remove more tooth structure to deliver standard needle irrigation to the smaller and more deli- cate apical anatomy, commonly seen in the apical one third. The resultsarecanalconven- ience forms that are more conservative, minimally invasive and biomimetic (Fig. 3), preventing the unnecessary removal oftoothstructure. Unlike other laser-activated irrigant techniques, PIPS is not a thermal event, rather subablative. Properly executed, PIPS creates turbulent photoacoustic agi- tation of irrigants that move fluids three dimensionally throughout the root canal systemevenasfarastheapicalterminus, distant from the radial stripped tip loca- tion.Byactivatingthetipintheaccesscav- ity and outside the root canal system, the extremely low energy needed to activate theuniquePIPStip(20mJsorless)isbelow the threshold of ablation for dentin. Ledg- ingandthermaleffectsthathaveplagued thewidespreaduseofotherlasersystems iscompletelyavoidedattheenergylevels usedbythePIPStechnique.5,6 Recent testing, performed at the Uni- versity of Tennessee by Dr. Adam Lloyd, chairmanofthedepartmentforendodon- tics, objectively confirmed the improved cleaning and debridement of organic and inorganic tissue left by instrumentation. Microcomputed tomography scans were usedtoassessbeforeandaftervolumetric change in the internal intaglio of lower first molars treated with PIPS protocol (Fig. 4). Sequential slicing beginning at 6mmfromtheapexandmovingdownto the last 2 mm demonstrated that all slice imagesshowedsignificantimprovements afterPIPS. Theimportanceofthesefindingsisfar reaching.PIPSnowoffersthedentistaless technique-sensitive, minimally invasive and time-reducing method for irrigating and preparing endodontic root canal sys- tems. Because PIPS has demonstrated its ability to decontaminate and debride areas that files and instrumentation can- not reach, success rates rise and retreat- mentforpastfailuresispossible.7 PIPS is also helpful in locating and helping negotiate calcified canals. PIPS is avaluableadditionaltoolinthetreatment of endodontics regardless of the shaping andobturationsystemused. Laser technology used in endodon- tics during the past 20 years has under- gone an important evolution. Research in recent years has been directed toward producing laser technologies (such as impulses of reduced length, radial-firing and stripped tips) and techniques (such as LAI and PIPS) that are able to simplify laser use in endodontics and minimize the undesirable thermal effects on the Fig. 1: Left, apical third of root treated with PIPS. Note clean surfaces without any thermal damage. Right, SEM of apical third showing extremely clean dentin tubules post PIPS with no sign of thermal dam- age. (Photos/Provided by Enrico Divito DDS ) PIPS with laser activated irrigation dentinalwalls,usinglower energies in the presence of chemical irrigants. EDTA has proved to be the best solution for the LAI technique that activates the liquid and enhances its cleaning of the smear layer. The use of a laser (PIPS) to activate sodium hypochlorite increases its antimicrobialactivity. Finally, using the cor- rectprotocol,thePIPStech- nique reduces the thermal effects and exerts both a stronger cleaning and bac- tericidal action, because of its streaming of fluids initiated by the photonic energy of the laser. Fur- ther studies are currently underway to validate LAI and PIPS technique as innovative technologies in modernendodontics. References 1. Clark D, Khademi JA. “Case studies in modern molar endodontic access and directed dentin conserva- tion” DentClin NorthAm. 2010:54:275–289. 2. Peters OA, Schonenberger K, Laib A. Effects of four Ni-Ti preparation techniques on root canal geometry assessed by micro- computed tomography. International EndodonticJournal 3. GeorgeR,MeyersIW,WalshLJ(2008)Laser activation of endodontic irrigants with im- proved conical laser fiber tips for removing smear layer in the apical third of the root canal.JEndod34:1524–1527 4.. 4. de Groot SD, Verhaagen B, Versluis M, Wu MK, Wesselink PR, van der Sluis LW (2009) Laser-activated irrigation within root can- als:cleaningefficacyandflowvisualization. IntEndodJ42:1077–1083. 5. Li Z., Code JE., Van De Merwe WP. Er:YAG Laser ablation of enamel and dentin of hu- man teeth: determination of the ablation rates at various fluences and pulse repeti- tion rates. Lasers in Surgery and Medicine. 1992,12:625–630. 6. Majaron B, Lukac M, Sustercic D, et al. Thresholdandefficiencyanalysis inEr:YAG laser ablation of hard dental tissue. Proc SPIE.1996;2922:233–242. 7. DiVito, E., O.A. Peters, and G. Olivi, Effect- iveness of the erbium:YAG laser and new designradialandstrippedtipsinremoving the smear layer after root canal instru- mentation. Lasers Med Sci, 2012. 27(2): p. 273–280. By Enrico Divito, DDS Fig. 2: Left, close-up of tapered and stripped PIPS tip used for laser activated irrigation. Right, position of the laser tip in the PIPS technique: steady in the pulp chamber and does not enter canal. Fig. 3: Left, pre-treatment. Right, post-treatment obturation after PIPS. Tooth instrumented to a #25/06 tapper. Note the conservative convenience form maintaining more original anatomy of root canal system and reducing the need to use larger file sizes, conserving more dentin tooth structure. Fig. 4: Left, mandibular molar canal system show- ing isthmus before (A, red canal) PIPS laser activated irrigation. Areas of organic tissue and debris from in- strumentation have been completely eliminated, as highlighted by post-PIPS image (B, green canal). Right, mandibular molar with canal preparation to a size 30/.04 (A, green canal) obturated with nano-particle BC Sealer (Brasseler USA, Savannah, Ga.) and single cone obturation (B, blue). About the author Dr. Enrico DiVito formed his dental prac- tice in 1980 in Scottsdale, Ariz. In 2004, he formed the Arizona Center for Laser Dent- istry. He is the founder and director of the state-accredited Arizona School of Dental Assisting (ASDA). In addition to teaching at ASDA, DiVito is also a clinical professor attheArizonaSchoolofDentistryandOral Health and is helping to create its depart- ment of laser dentistry. He earned his undergraduate degree from Arizona State Universityin1980andisagraduateofthe UniversityofthePacific,ArthurA.Dugoni SchoolofDentistrywithhonors,receiving severalclinicalexcellenceawards.Hecan be reached at edivito@azcld.com. Here at the PDC Learn more about the Lightwalker combined Er:YAG & Nd:YAG dental laser intheNationalDental Inc. booth, No. 1319. Photoacoustic shockwave with irrigant debrides areas of root canal files can’t reach Editor’s note: See case study on page 20