Differences According to the Type of Exogenous Hyaluronic Acid and its Frequency of Infiltration in the Treatment of Temporomandibular Osteoarthritis / Diferencias Según el Tipo de Ácido Hiaurónico Exógeno y su Frecuencia de Infiltración en el Tratamiento de la Osteoartritis Temporomandibular

SUMMARY: One of the most important minimally invasive treatments today in temporomandibular joint osteoarthritis (TMJ- OA) is the intra-articular exogenous hyaluronic acid (HA) injection, which has yielded good results in pain relief and improves mandibular function with few side effects. However, the effectiveness of HA continues to be controversial, partly due to the heterogeneity in the injection protocols in their molecular weight, viscosity and frequency of infiltration, among other properties. The aim of this review is to identify the differences in the histological and clinical effects of the different types of HA and the frequency of infiltration on TMJ-OA treatment. Materials and methods: A bibliographic search was performed in the PubMed, Web of Science and Scopus databases. The search was limited up to September 2022. Search terms included "osteoarthritis", "hyaluronic acid, "molecular weight", "concentration", "viscosity", "dose" and "temporomandibular", using AND/OR as Boolean terms. Results: Exogenous HA in its different molecular weights offers an improvement in histological and clinical characteristics. Apparently, low and medium molecular weight HA presents better results. No clinical studies related to the degree of HA viscosity were found. Respect to the frequency of infiltration, single injection, weekly injections for 3 weeks, weekly injections for 5 weeks and other protocols are used. However, their comparison is complex. There seems to be differences in the effects of the different HA preparations for the treatment of TMJ-OA, mainly in their molecular weight. However, the evidence remains scant.

Uno de los tratamientos mínimamente invasivos más importantes en la actualidad en la artrosis de la articulación temporomandibular (OATM) es la inyección intraarticular de ácido hialurónico (AH) exógeno, que ha dado buenos resultados en el alivio del dolor y mejora la función mandibular con pocos efectos secundarios. Sin embargo, la efectividad del AH continúa siendo controversial, en parte debido a la heterogeneidad en los protocolos de inyección en cuanto a su peso molecular, viscosidad y frecuencia de infiltración, entre otras propiedades. El objetivo de esta revisión fue identificar las diferencias en los efectos histológicos y clínicos de los diferentes tipos de HA y la frecuencia de infiltración en el tratamiento de TMJ-OA. Se realizó una búsqueda bibliográfica en las bases de datos PubMed, Web of Science y Scopus. La búsqueda se limitó hasta septiembre de 2022. Los términos de búsqueda incluyeron "osteoartritis", "ácido hialurónico", "peso molecular", "concentración", "viscosidad", "dosis" y "temporomandibular", utilizando AND/OR como términos booleanos. El HA exógeno en sus diferentes pesos moleculares ofrece una mejora en las características histológicas y clínicas. Aparentemente, el AH de bajo y medio peso molecular presenta mejores resultados. No se encontraron estudios clínicos relacionados con el grado de viscosidad del HA. Respecto a la frecuencia de infiltración, se utilizan inyecciones únicas, inyecciones semanales durante 3 semanas, inyecciones semanales durante 5 semanas y otros protocolos. Sin embargo, su comparación es compleja. Parece haber diferencias en los efectos de las diferentes preparaciones de HA para el tratamiento de la OA-TMJ, principalmente en su peso molecular. Sin embargo, la evidencia sigue siendo escasa.

Effect of bleaching protocols on surface roughness and color change of high- and low-viscosity bulk-fill composite resins / Efeito de protocolos clareadores na rugosidade de superfície e alteração de cor de resinas compostas bulk-fill de alta e baixa viscosidade

ABSTRACT The aim of this in vitro study was to evaluate the effect of bleaching protocols on the surface roughness (Ra), color change and surface micromorphology of a low-viscosity bulk-fill composite (Filtek Bulk Fill Flow, 3M ESPE), a highviscosity bulk-fill composite (Filtek Bulk Fill, 3M ESPE) and a conventional nanoparticulate composite resin (control) (Filtek Z350 XT, 3M ESPE). Forty samples of each composite (disks 5 mm in diameter and 2 mm thick) were randomly divided into four groups (n=10), according to bleaching protocol: a) 10% carbamide peroxide gel (Opalescence, Ultradent Products) (2 h/ day, for 14 days); b) 40% hydrogen peroxide gel (Opalescence Boost, Ultradent Products) (three bleaching sessions, once a week, 45 min/session); c) whitening rinse (Listerine Whitening Extreme, Johnson & Johnson) (2 min/day, for 14 days); and d) distilled water (control). The samples were submitted to triplicate readings (Ra and color [CIELAB parameters]) before and after contact with bleaching protocols. Micromorphology was analyzed in a scanning electron microscope (SEM). Ra and color parameters (ΔL, Δa, Δb and ΔE) were analyzed by generalized linear models (α=0.05). The Ra of the high-viscosity bulk-fill was significantly higher than that of the other composites (p<0.05). Ra increased significantly (p<0.05) and surface became more irregular (SEM analysis) in all the composite resins, regardless of the bleaching protocol (p<0.05). The high-viscosity bulk-fill composite resin group had significantly lower ΔE (p<0.05) than the nanoparticulate composite resin group immersed in distilled water. It was concluded that the characteristics of each resin significantly influenced the Ra more than the bleaching protocol. The high-viscosity bulk-fill resin presented minor color change.

RESUMO Este estudo in vitro teve objetivo de avaliar o efeito de protocolos clareadores sobre a rugosidade de superfície (Ra), alteração de cor e micromorfologia de resina bulk-fill de baixa viscosidade (Filtek Bulk Fill Flow, 3M ESPE), alta viscosidade (Filtek Bulk Fill, 3M ESPE) e de uma resina composta nanoparticulada (controle) (Filtek Z350 XT, 3M ESPE). Quarenta amostras de cada resin composta (discos de 5 mm de diâmetro e 2 mm de espessura) foram aleatoriamente divididas em quatro grupos , de acordo com protocolo clareador (n=10): a) Gel de peróxido de carbamida (Opalescence, Ultradent Products) (2 horas/dia, por 14 dias); b) Gel de peróxido de hidrogênio (Opalescence Boost, Ultradent Products) (3 sessões de clareamento, uma por semana, 45 min/sessão); enxaguatório clareador (Listerine Whitening Extreme, Johnson & Johnson) (2 min/dia, por 14 dias); d) água destilada (controle). As amostras foram submetidas a leituras, em triplicata (Ra e cor (parâmetros CIELab) antes e depois do contato com os protocolos clareadores. A micromorfologia de superfície foi conduzida em microscópio eletrônico de varredura (MEV). Ra e parâmetros de cor (ΔL, Δa, Δb e ΔE) foram analisados por modelos lineares generalizados (α=0.05). A Ra da resina bulk-fill de alta viscosidade foi significantemente superior do que para os outros compósitos (pp<0.05). A Ra aumentou significantemente (p<0.05) e a superfície ficou mais irregular (MEV) para todos os compósitos, independente do protocolo clareador (pp<0,05). A resina bulk-fill de alta viscosidade obteve menor ΔE (pp<0.05) do que a resina composta nanoparticulada, imersa em água destilada. Pode-se concluir que as características de cada resina composta influenciaram de forma mais significativa a Ra do que o protocolo clareador. A resina bulk fill de alta viscosidade apresentou menor alteração de cor.

Effect of estrogen administration on middle cerebral arterial viscoelastic properties in aged female rats

ABSTRACT PURPOSE: To develop a model for studying cerebrovascular disease prevention in elderly women. METHODS: Sixty 18-month-old Sprague Dawley (SD) rats were randomly divided into an estrogen administration group (EA, n=30) and a non-administration group (NA, n=30); thirty 4-month-old SD rats were allocated to a control group. The EA group received estradiol benzoate starting on the 5th day of a 34-day breeding period, and the serum levels of estradiol (E2), estrogen receptor (ER), and malondialdehyde (MDA) were measured. The MCA of each group was then sampled for viscoelastic experiments. RESULTS: The serum levels of E2 and MDA in the EA group showed significant differences compared to those in the control group (p<0.05), while the difference in ER between the EA and control groups was not significant (p>0.05). The decrease in MCA stress at 7,200 s and the increase in strain at 7,200 s in the EA group showed no significant differences compared to the control group (p>0.05). CONCLUSION: Estradiol administration inhibited the formation of lipid peroxidation products and restored middle cerebral arterial viscoelasticity in aged female rats.

[ effects of N-acetyl-l-cysteine on reduction of semen viscosity]

Hyperviscous semen is an etiologic cause for male-related infertility which is related to function of oxidative systems in the cells. So, use of anti-oxidants may be useful. Hence, this study was conducted to evaluate the efficacy of N-acetyl-l-cysteine in reduction of seminal viscosity. In this experimental study, 200 patients attending to urology clinic of Amiralmomenin hospital with hyperviscouse semen were selected and treated with N-acetyl-l-cysteine, 500 mg twice a day for one month. Sperm analysis was repeated after treatment and 10 days later. After treatment, the viscosity which was initially high in all patients was normal in 124 men [62%], high in 60 patients [30%], and low in 16 subjects [8%]. Also sperm count, motility, and morphology were improved significantly after the treatment [p< 0.05]. According to 70 percent efficacy for Nacetyl-l-cysteine and lack of any drug adverse effects, this therapeutic modality may be indicated upon with patient's conditions and physician's opinion

Variación de la viscosidad en un sustituto salival en base a mucina por cambios en el pH y la concentración de proteinas / Variation of the viscosity in mucin saliva substitute by changes in the pH and proteins concentrations

Una de las funciones de la saliva es proteger las superficies bucales y faríngeas para así mantener la integridad de estos tejidos. La saliva debe la función protectora a su capacidad humectante, lubricante etc. Las cuales a su vez se deben a los elementos que la componen, principalmente a las proteínas y a las glicoproteínas (mucinas) de alto peso molecular. Estos compuestos son políones enfotéricos que tienen carga neta positiva o negativa determinada por la ionización de los grupos polares en sus cadenas laterales, que es dependiente del pH del medio. Por lo tanto un cambio en el pH del medio puede causar variaciones en: la carga neta de la proteína, enlace de hidrógeno, las interaciones hidrofólicas etc., lo que afecta su conformación y puede ocacionar la formación de agregados moleculares. La conformación y la interacción entrw macromoléculas salivales afectan la viscosidad de la solución en la cual se encuentran disueltas. La viscosidad es el principal factor determinante de la capacidad lubricante del fluido salival. Por esta razón, la viscosidad es un parámetro de medida de los factores que modifican la capacidad lubricante de la saliva. Estudios realizados por Veerman et al, y Nordbo et al, indican que los cambios en el pH del medio influencian significativamente la viscosidad de la saliva total humana y de sustitutos salivales a base de mucina. Sin embargo, hay una gran discrepancia entre los valores de pH a los cuales se reporta un cambio de la viscosidad