Evaluation of two protocols for low-level laser application in patients submitted to orthodontic treatment

Abstract

Introduction:Different low-level laser (LLL) irradiation protocols have been tested to accelerate orthodontic tooth movement (OTM). Nevertheless, divergent results have been obtained. It was suggested that the stimulatory action of low level laser irradiation occurs during the proliferation and differentiation stages of bone cellular precursors, but not during later stages. Objective: The purpose of this study was to determine the effect of two protocols of LLL irradiation on experimental tooth movement: One with daily irradiations and another with irradiations during the early stages. Methods: Thirty-six rats were divided into control groups (CG1, CG2, CG3) and irradiated groups (IrG1, IrG2, IrG3) according to the presence of: experimental tooth movement, laser irradiation, type of laser irradiation protocol and date of euthanasia (3th or 8th day of experiment). At the end of experimental periods, a quantitative evaluation of the amount of OTM was made and the reactions of the periodontium were analyzed by describing cellular and tissue reactions and by counting blood vessels. Results: The amount of OTM revealed no significant differences between groups in the same experimental period (p < 0.05). Qualitative analysis revealed the strongest resorption activity in irradiated groups after seven days, especially when using the daily irradiation protocol. There was a higher number of blood vessels in irradiated animals than in animals without orthodontic devices and without laser irradiation (p < 0.05). Conclusion: Moreover, angiogenesis was verified in some of the irradiated groups. The irradiation protocols tested were not able to accelerate OTM and root resorption was observed while they were applied. Keywords: Lasers. Low-level laser therapy. Tooth movement. Angiogenesis inducing agents. Introdução: diferentes protocolos de irradiação por laser de baixa potência (LBP) têm sido testados para potencializar o movimento ortodôntico; entretanto, há resultados divergentes. Foi sugerido que seu efeito bioestimulador ocorre nas fases de proliferação e diferenciação celular, não agindo em estágios tardios. Objetivo: avaliar o efeito de dois protocolos de irradiação do LBP na movimentação ortodôntica: um com irradiações diárias e outro em que irradiações foram realizadas apenas nos períodos iniciais. Métodos: trinta e seis ratos Wistar foram divididos em grupos controles (GC1, GC2 e GC3) e irradiados (GIr1, GIr2 e GIr3), de acordo com a presença de dispositivo ortodôntico, a presença de irradiação, o tipo de protocolo de irradiação e a data de eutanásia (3º ou 8º dia de experimento). Ao final dos períodos experimentais, foram realizadas mensurações da movimentação dentária, análise qualitativa das reações celulares e teciduais do periodonto e contagem de vasos sanguíneos no ligamento periodontal. Resultados: a quantidade de movimentação não diferiu entre os grupos num mesmo tempo experimental (p < 0,05). A análise qualitativa revelou maior atividade absortiva nos grupos irradiados ao final de 7 dias, especialmente quand...

Low Intensity Laser Influence on Orthodontic Movement: A Randomized Clinical and Radiographic Trial

“…Other studies also concluded that greater energies induce a null effect. 16,30 Oppositely, Heravi used a smaller dose (total energy of 6 J with energy density of 21.4 J/cm 2 per point), similar to those used in studies that were efficient in accelerating tooth movement. 12,13,21 However, there was no significant increase in tooth movement.…”

“…It is simple, local, quick, and painless. [12][13][14][15][16][17] The term "laser" is the acronym for "light amplification by stimulated emission of radiation." This type of radiation is different from others.…”

Effects of Low-Level Laser Therapy and Bracket Systems on Root Resorption during Orthodontic Treatment: A Randomized Clinical Trial

“…Suzuki et al (2018) presented a less crater on the tooth root in rats treated with LLLT [ 12 ]. On the other hand, Marquezan et al (2013) found evidence of RR on the eighth day of orthodontic tooth movement (OTM) with the application of LLLT [ 13 ]. Due to the contrasting outcomes, this study intended to assess the effectiveness of LLLT on RR via cone-beam computed tomography (CBCT) along with the conventional bracket (CB) and self-ligating (SL) bracket systems until the leveling and alignment stage of the orthodontic treatment.…”

Efeito do LED infravermelho sobre a movimentação dentária induzida em ratos

“…No presente trabalho foi empregada a microtomografia computadorizada in vivo para quantificar o deslocamento dentário, diferente dos estudos de A maioria das pesquisas, clínicas ou em animais experimentais, em ortodontia, que investigam o efeito da luz infravermelha durante a movimentação dentária, relacionam a aplicação do laser durante movimentação ortodôntica (Lim et al, 1995;Kawasaki;Shimizu, 2000;Cruz et al, 2004;Limpanichkul et al, 2006;Turhani et al, 2006;Seifi et al, 2007;Youssef et al, 2008;Fujita et al, 2008;Tortamano et al, 2009;Yoshida et al, 2009;Abi-Ramia et al, 2010;Habib et al, 2010;Gama et al, 2010;Marquezan et al, 2010;Yamaguchi et al, 2010;Sousa et al, 2011;Altan et al, 2012;Duan et al, 2012;Habib et al, 2012;Bicakci et al, 2012;Marquezan et al, 2013;Cossetin et al, 2013;Genc et al, 2013;Velásquez 2013;Kansal et al, 2014;Seifi et al, 2014;Hevari et al, 2014;Shirazi et al, 2015;Domínguez et al, 2015). O LED é pouco investigado como fonte de energia luminosa para verificar sua influência durante o movimento ortodôntico.…”

“…Os achados sobre a quantidade de reabsorção radicular também mostraram resultados conflitantes; alguns autores afirmam que a luz infravermelha diminui a reabsorção radicular (Fonseca et al, 2013;Seifi et al, 2014;Ekizer et al, 2015) enquanto outros autores não encontraram diferença entre os grupos. (Marquezan et al, 2013).…”