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ePaper created 2016-03-11, 23:13:06 | version 1.38.0
issue 2016 — 73 Endodontics Article cleaning capability, endodontic research is oriented toward the identification of al- ternative solutions that could further re- fine disinfection and assist in the destruc- tion of biofilms and the elimination of micro-organisms.Forthispurpose,differ- ent substances and technologies have beeninvestigatedovertimewithdifferent results. — Photoactivated disinfection A new method recently introduced in en- dodontics is photoactivated disinfection. This technique is based on the principle thatthephotosensitizingmolecules(pho- tosensitizer, PS) havethe abilityto bindto the membranes of the bacteria. The PS is activated with a specific wavelength and produces free oxygen, which causes the rupture of the bacterial cell wall on which the PS is associated, determining a bacte- ricidalaction.34 Extensivelaboratorystud- ies have shown that the two components do not produce any effect on bacteria or onnormaltissuewhenusedindependently of each other; it is only the combination ofPSandlightthatexerttheeffectonthe bacteria.34 An endodontic system called light- activated disinfection (LAD) has been de- veloped based on a combination of a PS and a special light source. The PS attacks the membranes of micro-organisms and binds to their surface, absorbs energy from light andthen releasesthis energyin the form of oxygen, which is transformed into highlyreactive forms that effectively destroymicro-organisms.LADiseffective not only against bacteria, but also against other micro-organisms, including viruses, fungi and protozoa. The PSs have far less affinityforthecellsofthebody;therefore, toxicitytestscarriedoutdidnotreportad- verse effects of this treatment. Clinically, after root canal preparation, the PS is in- troduced into the canal to working length withanendodonticneedleandisleftinsitu for 60 s to allow the solution to come into contact with the bacteria and spread through any structures, such as biofilms. The specific endodontic tip is then in- serted into the root canal up to the depth that can be reached and irradiation is per- formed for30 s in each canal (Fig. 4).This technique has proven to be effective in laboratorystudiesateliminatinghighcon- centrations of bacteria present in artifi- cially infected root canals.35 Care should be taken to ensure maximum penetration ofthePS,sinceitisimportantthatitcome into direct contact with the bacteria, oth- erwise the effect of photosensitivity will not occur. In addition, LAD appears to be effective not only against the bacteria in suspension, but also against biofilm.5 Re- search is now directed toward evaluating thepossibilityofincreasingtheantibiofilm effectivenessofLAD,combiningtheben- efits of photodynamic therapy with those of bioactive glasses and nanoparticles, which will be described later. Currently LAD is not considered as an alternative, but rather as a possible supplement to standard protocols of root canal disinfec- tion already in use.5 — Laser Oneofthemaindisadvantagesofthecur- rentendodonticirrigantsisthattheirbac- tericidal effect is limited primarily to the main root canal. In the endodontic field, several types of lasers have been used to improverootcanaldisinfection:thediode laser, carbon dioxide laser, Er:YAG laser Fig.3 Fig.4 Fig. 3 Apical negative-pressure irrigation system used to enhance debridement. Fig. 4 Disinfection activated by light to enhance root canal cleaning. Article_Plotino_00-00.qxp_Layout 1 02.03.16 22:18 Seite 4 Article_Plotino_00-00.qxp_Layout 102.03.1622:18 Seite 4