Effects of 970 nm diode laser irradiation on morphology, proliferation, and differentiation of gingival mesenchymal stem cells / Efectos de la irradiación con láser de diodo de 970 m sobre la morfología, la proliferación y la diferenciación de las células madre mesenquimales gingivales

Objective: The objective of this study was to investigate the morphology, proliferation, and differentiation of gingival mesenchymal stem cells (GMSCs) irradiated with a 970 nm Diode Laser (LLLT). It is essential to validate the efficacy of treatment, optimize irradiation conditions and guarantee the safety and quality of stem cells for future use in dental applications. Materials and Methods: GMSCs were cultured in standard conditions and irradiated with a Diode laser (970 nm, 0.5W) with an energy density of 9J/cm2. Cell proliferation was assessed with the WST-1 proliferation kit. GMSCs were differentiated into chondrogenic and osteogenic lineages. Cell morphology was performed with Hematoxylin/eosin staining, and quantitative nuclear analysis was done. Cell viability was monitored with trypan blue testing. Results: GMSCs subjected to irradiation demonstrated a significant increase in proliferation at 72 hours compared to the non-irradiated controls (p=0.027). This indicates that the 970 nm diode laser has a stimulatory effect on the proliferation of GMSCs. LLLT-stimulated GMSCs exhibited the ability to differentiate into chondrogenic and osteogenic lineages. A substantial decrease in cell viability was observed 24 hours after irradiation (p=0.024). However, after 48 hours, the cell viability recovered without any significant differences. This indicates that there might be a temporary negative impact on cell viability immediately following irradiation, but the cells were able to recover and regain their viability over time. Conclusions: This study support that irradiation with a 970 nm diode laser could stimulate the proliferation of GMSCs, maintain their ability to differentiate into chondrogenic and osteogenic lineages, and has minimal impact on the mor- phological characteristics of the cells. These results support the potential use of NIR Lasers in combination with GMSCs as a promising strategy for dental treatments.

Objetivo: El objetivo de este estudio fue investigar la morfología, proliferación y diferenciación de las células madre mesenquimatosas (GMSC) irradiadas con un láser de diodo de 970 nm (LLLT). Es fundamental validar la eficacia del tratamiento, optimizar las condiciones de irradiación y garantizar la seguridad y calidad de las células madre para su uso futuro en aplicaciones dentales.Materiales y Métodos: Las GMSC se cultivaron en condiciones estándar y se irradiaron con un láser de diodo (970 nm, 0,5 W) con una densidad de energía de 9 J/cm2. La proliferación celular se evaluó con el kit de proliferación WST-1. Las GMSC se diferenciaron en linajes condrogénicos y osteogénicos. La morfología celular se realizó con tinción de hematoxilina/eosina y se realizó un análisis nuclear cuantitativo. La viabilidad celular se controló con prueba de azul de tripano. Resultados: Las GMSC sometidas a irradiación demostraron un aumento significativo en la proliferación a las 72 horas en comparación con los controles no irradiados (p=0,027). Esto indica que el láser de diodo de 970 nm tiene un efecto estimulante sobre la proliferación de GMSC. Las GMSC estimuladas con LLLT exhibieron la capacidad de diferenciarse en linajes condrogénicos y osteogénicos. Se observó una disminución sustancial de la viabilidad celular 24 horas después de la irradiación (p=0,024). Sin embargo, después de 48 horas, la viabilidad celular se recuperó sin diferencias significativas. Esto indica que podría haber un impacto negativo temporal en la viabilidad de las células inmediatamente después de la irradiación, pero las células pudieron recuperarse y recuperar su viabilidad con el tiempo. Conclusión: En conclusión, este estudio respalda que la irradiación con un láser de diodo de 970 nm podría estimular la proliferación de GMSC, mantener su capacidad para diferenciarse en linajes condrogénicos y osteogénicos y tiene un impacto mínimo en las características morfológicas de las células. Estos resultados respaldan el uso potencial de láseres NIR en combinación con GMSC como una estrategia prometedora para tratamientos dentales.

Influence Of Different Bleaching Systems On The Bond Strength Of Laminate Veneer To Enamel

Purpose:The objective of this in-vitro study was to examine the microtensile bond strength of a porcelain laminate veneer (PLV) to tooth surface bleached with photoactivation by blue light-emitting diode (LED) or diode laser. Methods:Eigthteen extracted human central incisors were randomly divided into three groups. Two sticks were obtained from each tooth (n=12). Before surface treatments; teeth were prepared to provide space for PLVs. The first group teeth were bleached with Whiteness HP which is contain 35% hydrogen peroxide (HP) and then photoactivated with a LED for 20 seconds. The second group were bleached with Laserwhite 20 which is contain 46% HP and photoactivated with a diode laser for 30 seconds. The third group received no surface treatment and served as the control group. IPS Esthetic ceramic veneers were luted with Variolink II veneer cement . The teeth were sectioned to obtain porcelain-resin-enamel/dentin sticks and submitted to a MTB testing device. The maximum load at fracture was recorded. Data were analyzed using one-way ANOVA followed by the Tukey HSD post-hoc test at a preset α of 0.05. Results:One-way ANOVA revealed that there was significant difference between LED unit group and control group (p<.05) but no statistical differences were observed with diode laser group (p>.05) The LED unit group presented significantly lower bond strength value (6.49±2.3 MPa) than diode laser (8.49±3.1 MPa) and control groups (9.53±2.7 MPa). Conclusion:The results suggested that bleaching therapy with activation by LED or diode laser reduced the bond strength of IPS Esthetic ceramic veneers to tooth surfaces.

O uso do laser na reabilitação das desordens temperomandibulares / The use of laser in the rehabilitation of temporomandibular disorders

Introdução: Entende-se disfunção temporomandibular como um termo coletivo que envolve um grande número de problemas clínicos que afetam os músculos mastigatórios, a articulação temporomandibular (ATM)e estruturas associadas. Dentre os principais sinais e sintomas, incluem-se dores nos músculos da mastigação ou na ATM, ruídos articulares, limitação de abertura, retração gengival, oclusão inadequada, distúrbios auditivos, cefaleias, sensibilidade em toda a musculatura do sistema estomatognático e cervical. Objetivos:Estudar a influência da laserterapia de baixa intensidade (diodo) no tratamento das desordens temporomandibulares.Materiais e métodos: Trata-se de uma revisão sistemática. Foram consultadas as seguintes bases de dados: BIREME, MEDLINE, PubMed, Science Direct e LILACS. Os termos de busca utilizados foram “temporomandibular laser therapy” e “ATM laser treatment”, em inglês e português. Não foram estabelecidos limites de busca. Após a busca independente de dois revisores, foram encontrados 1.344 artigos e, após a aplicação dos critérios de exclusão, 12 artigos foram selecionados para a análise. Resultados: Dos 12 artigos selecionados, apenas em 1 (um) deles não foi verificada qualquer melhora do quadro doloroso na ATM em virtude dos diversos tipos de DTM. Conclusão: Apesar dos resultados satisfatórios do uso do laser na redução sintomática da dor nos DTM, ainda é controversa a utilização dos seus parâmetros para cada caso.Por isso, sugerimos a realização de outros estudos para que essas lacunas sejam preenchidas com o objetivo maior de promover uma melhor qualidade de vida para as pessoas que sofrem quaisquer transtornos na região da ATM.

INTRODUCTION: It is understood by temporomandibular dysfunction as a collective term that involves a large number of clinical problems affecting the masticatory muscles, the temporomandibular joint (TMJ) and associated structures. Among the major signs and symptoms there are pain in the masticatory muscles or TMJ, joint sounds, limitation of opening, gingival recession, inadequate occlusion, hearing disorders, headache, tenderness in the whole musculature of the stomatognathic system and cervical cancer. OBJECTIVES: To study the influence of low intensity laser therapy (LLI) in the treatment of temporomandibular disorders.MATERIALS AND METHODS: This is a systematic review. We consulted the following databases: BIREME, MEDLINE, PubMed, Science Direct and LILACS. The search terms used were "temporomandibular laser therapy" and "ATM laser treatment", in English and Portuguese. No search limits were established. During the search conducted by two independent reviewers, 1.344 articles were found, and after application of the exclusion criteria, 12 articles were selected for analysis. RESULTS: Out of the 12 selected articles, only in one of them it was not observed any improvement in the painful TMJ because of the different types of TMJ. CONCLUSION: Despite the satisfactory results of laser use in reducing symptomatic pain in TMJ, the use of its parameters for each case is controversial, so we suggest that the foundation for other studies that these gaps may be filled with the larger goal of promoting a better quality of life for people who suffer any inconvenience in the TMJ region.

Healing cutaneous wounds through laser irradiation / 中华物理医学与康复杂志

Objective To quantify the effect of 650 nm semiconductor laser irradiation on cutaneous wound healing in rabbits. Methods Model wounds were induced in 21 adult male rabbits. They were then divided randomly into a control group, a 5 mW irradiation group and a 10 mW irradiation group. Biometry and light microscopy were used to investigate the effect of low intensity laser therapy (LILT) on cutaneous wound healing. Results Statistically significant differences were observed among the groups in terms of wound shrinkage. The differences between the irradiated and control groups were significant at the 5th, 9th and 13th day. However, any differences between the S mW and 10 mW groups were not significant. Conclusions LILT at 650 nm at either 5 mW or 10 mW and 1 J/cm2 accelerates cutaneous wound healing in rabbits. But irradiation at 10 mW is no more effective than at 5 mW.

The effects of semiconductor laser irradiation and a high voltage static electric field on small vessel impairment in diabetic rats / 中华物理医学与康复杂志

Objective To study the effects of semiconductor laser irradiation and high voltage static electric fields on small vessel damage in diabetic rats.Methods Fifty healthy male Wistar rats were randomly divided into two groups:8 rats in a normal group and 42 in a diabetic model group.The diabetic models were created by intrape- ritoneal injection of streptozocin.The diabetic model rats were randomly divided into four subgroups:a diabetes group,a semiconductor laser treatment group,a high voltage static electric field treatment group and a comprehensive treatment group receiving combined semiconductor laser and high voltage static electric field exposure.The rats in each treatment group were subjected to the corresponding intervention.After 20 days of treatment,the venous blood, kidney tissue and myocardium tissue of the rats were collected,and the concentrations of blood glucose,insulin,en- dothelin and tissue were detected.Results Compared with the normal group,a significant increase in blood glu- cose and endothelin was observed in the diabetic model group,along with significantly decreased blood insulin and significant small vessel endothelium proliferation in the kidney tissue.Compared with the diabetes group,endothelin levels were significantly lower in all 3 treatment groups,and blood insulin was also higher in the comprehensive treat- ment group.Conclusion There were severe abnormalities in blood glucose,insulin and endothelin as well as mild impairment of small vessel endothelium proliferation in the diabetic rats.Semiconductor laser and high voltage static electric field exposure have a role in treating and preventing these conditions in diabetic rats.