Citation: St˘ anus , i, A.S , .; Popa, D.L.; Ionescu, M.; Cump ˘ at˘ a, C.N.; Petrescu, G.S.; ¸ Tuculin˘ a, M.J.; D ˘ aguci, C.; Diaconu, O.A.; Gheorghit , ˘ a, L.M.; St˘ anu¸ si, A. Analysis of Temperatures Generated during Conventional Laser Irradiation of Root Canals—A Finite Element Study. Diagnostics 2023, 13, 1757. https://doi.org/ 10.3390/diagnostics13101757 Academic Editors: Francesco Inchingolo and Daniel Fried Received: 2 March 2023 Revised: 3 May 2023 Accepted: 11 May 2023 Published: 16 May 2023 Copyright: © 2023 by the authors. Licensee MDPI, Basel, Switzerland. This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY) license (https:// creativecommons.org/licenses/by/ 4.0/). diagnostics Article Analysis of Temperatures Generated during Conventional Laser Irradiation of Root Canals—A Finite Element Study Adrian S , tefan Stănus , i 1,† , Drago¸ s Lauren¸tiu Popa 2, *, Mihaela Ionescu 3 , Cristian Niky Cumpătă 4,† , Gabriel Sebastian Petrescu 5,† , Mihaela Jana ¸ Tuculină 1, * , Constantin Dăguci 6 , Oana Andreea Diaconu 1 , Lelia Mihaela Gheorghit , ă 1 and Andreea Stănu¸ si 7,† 1 Department of Endodontics, Faculty of Dental Medicine, University of Medicine and Pharmacy of Craiova, 200349 Craiova, Romania; leliagheorghita@yahoo.com (L.M.G.) 2 Faculty of Mechanics, University of Craiova, 200349 Craiova, Romania 3 Department of Medical Informatics and Biostatistics, Faculty of Medicine, University of Medicine and Pharmacy of Craiova, 200349 Craiova, Romania 4 Department of Oral and Maxillofacial Surgery, Faculty of Dental Medicine, University Titu Maiorescu of Bucharest, 67A Gheorghe Petrascu Str., 031593 Bucharest, Romania 5 Department of Oral and Maxillofacial Surgery, Faculty of Dental Medicine, University of Medicine and Pharmacy of Craiova, 200349 Craiova, Romania 6 Department of Oro-Dental Prevention, Faculty of Dental Medicine, University of Medicine and Pharmacy of Craiova, 200349 Craiova, Romania 7 Department of Prosthodontics, Faculty of Dental Medicine, University of Medicine and Pharmacy of Craiova, 200349 Craiova, Romania * Correspondence: popadragoslaurentiu@yahoo.com (D.L.P.); mtuculina@yahoo.com (M.J.T , .) † These authors contributed equally to this work. Abstract: The success of endodontic treatment is dependent on the removal of bacteria. A modern strategy to reduce bacterial load is laser irradiation. During this procedure, there is a local increase in temperature with possible side effects. The aim of this study was to determine the thermal behavior of a maxillary first molar when performing the conventional irradiation technique using a diode laser. For this study, a 3D virtual model of a maxillary first molar was created. The preparation of the access cavity, the rotary instrumentation of the palatal root canal and the laser irradiation protocol were simulated. The model was exported in a finite element analysis program where the temperature and heat flux were studied. Temperature and heat flux maps were obtained, and the temperature increase on the internal wall of the root canal was analyzed. The maximum temperature value exceeded 400 ◦ C and was maintained for less than 0.5 s. The obtained temperature maps support the bactericidal effect of diode laser and the limitation of damage to surrounding tissues. On internal root walls, the temperature reached several hundred degrees Celsius, but for very short durations. Conventional laser irradiation is an adjuvant method of decontamination of the endodontic system. Keywords: finite element analysis; endodontic decontamination; diode laser 1. Introduction The standard of care for a tooth with pulp and/or periapical lesions is endodontic treatment that ensures its functionality in the entire dento-maxillary apparatus and in- creases the patient’s quality of life [1]. The success of endodontic treatment is mainly dependent on the removal of bacteria and the smear layer inside the root canals [2,3]. The conventional preparation of the root canal is associated with irrigation with various solutions that have bactericidal action (sodium hypochlorite, EDTA) and that require direct contact with the dentine surface. Modern techniques for mechanical instrumentation of root canals involve the use of endodontic files with a large taper and present various risks, such as perforations and stripping. At the same time, by using these endodontic techniques, the walls of the root Diagnostics 2023, 13, 1757. https://doi.org/10.3390/diagnostics13101757 https://www.mdpi.com/journal/diagnostics