Maria Amália Gonzaga Ribeiro

Effect of low-level laser therapy on pain levels in patients with temporomandibular disorders: a systematic review

Temporomandibular disorders (TMD) are characterized by the presence of temporomandibular joint (TMJ) and/or masticatory muscle pain and dysfunction. Low-level laser is presented as an adjuvant therapeutic modality for the treatment of TMD, especially when the presence of inflammatory pain is suspected. Objective To systematically review studies that investigated the effect of low level laser therapy (LLLT) on the pain levels in individuals with TMD. Material and Methods The databases Scopus, embase, ebsco and PubMed were reviewed from January/2003 to October/2010 with the following keywords: laser therapy, low-level laser therapy, temporomandibular joint disorders, temporomandibular joint dysfunction syndrome, temporomandibular joint, temporomandibular, facial pain and arthralgia, with the inclusion criteria for intervention studies in humans. exclusion criteria adopted were intervention studies in animals, studies that were not written in english, Spanish or Portuguese, theses, monographs, and abstracts presented in scientific events. Results After a careful review, 14 studies fit the criteria for inclusion, of which, 12 used a placebo group. As for the protocol for laser application, the energy density used ranged from 0.9 to 105 J/cm2, while the power density ranged from 9.8 to 500 mW. The number of sessions varied from 1 to 20 and the frequency of applications ranged from daily for 10 days to 1 time per week for 4 weeks. A reduction in pain levels was reported in 13 studies, with 9 of these occurring only in the experimental group, and 4 studies reporting pain relief for both the experimental group and for the placebo. Conclusion Most papers showed that LLLT seemed to be effective in reducing pain from TMD. However, the heterogeneity of the standardization regarding the parameters of laser calls for caution in interpretation of these results. Thus, it is necessary to conduct further research in order to obtain a consensus regarding the best application protocol for pain relief in patients with TMD.

Immunohistochemical assessment of myofibroblasts and lymphoid cells during wound healing in rats subjected to laser photobiomodulation at 660 nm

OBJECTIVE The goal of this study was to assess the biomodulatory effect of low-level laser therapy (LLLT) on myofibroblasts and T and B cells during wound healing. BACKGROUND DATA Phtotobiomodulation using LLLT has been extensively applied to improve wound healing. MATERIALS AND METHODS Standardized artificial surgical wounds were made on the backs of 24 male rats. Half of them underwent LLLT (20 J/cm(2)) at 660 nm delivered for 7 d. At 8 and 14 d post-surgery the healing wounds were removed and immunohistochemical analysis of myofibroblasts, T cells, and B cells was carried out. The mean of each cell subset was calculated and compared to one another using two-way analysis of variance (ANOVA) and Tukeys test. RESULTS The average number of myofibroblasts was statistically significantly higher in the irradiated group than in the non-irradiated group on the eighth (p = 0.001) but not the 14th (p = 0.555) day. B and T cells were significantly more conspicuous in the irradiated group on both the eighth (p = 0.004 and 0.02, respectively) and 14th days (p = 0.04 and 0.03, respectively). CONCLUSIONS Our results suggest that LLLT facilitates myofibroblastic differentiation during the early stages of the cicatricial repair process. Furthermore, LLLT also appears to modulate the inflammatory response by downregulating lymphocytic proliferation during the wound healing process.

Improvement of dermal burn healing by combining sodium alginate/chitosan-based films and low level laser therapy.

This paper aimed to evaluate the improvement of burn wounds healing by sodium alginate/chitosan-based films and laser therapy. Natural polymers with different biological activities are widely used as film dressings to improve wound healing. Lasers arrays accelerate the healing repair of soft tissue injuries. Burn procedures were performed on the backs of 60 male rats assigned into six groups: untreated (CTR), dressed with cellulose films (CL), dressed with sodium alginate/chitosan-based films (SC), laser-irradiated undressed wounds (LT), laser-irradiated wounds with cellulose (CLLT) and sodium alginate/chitosan-based films (SCLT). Laser therapy was applied for 7 days. Animals of each group were euthanised 8 and 14 days after the burn procedures. The inflammatory reaction was significantly more intense in the CTR group than in the irradiated groups after 8 and 14 days. Laser therapy stimulated myofibroblastic differentiation in 8 days, with or without dressing films. Combined laser therapy and both dressings improved epithelisation, blood vessels formation and collagenization, promoted rapid replacement of type III for type I collagen and favored the better arrangement of the newly formed collagen fibres. The combination of laser therapy and sodium alginate/chitosan-based dressing improves burn healing, apparently by modulating the epithelisation, blood vessels formation and collagenization processes.

Effect of Bovine Type-I Collagen-Based Films Containing Red Propolis on Dermal Wound Healing in Rodent Model

El propoleo es un producto apiterapico ampliamente usado en medicina natural, que presenta diversas propiedades biologicas, como actividad bactericida y anti-inflamatoria, pero pocos informes han examinado la variedad brasilena del propoleo rojo. Peliculas de colageno han sido empleadas para mejorar la cicatrizacion de heridas y en algunos estudios se ha investigado el efecto de los productos naturales incorporados en estas peliculas. Asi el objetivo de este estudio fue analizar el efecto de las peliculas a base de colageno que contienen propoleo rojo en la cicatrizacion de heridas. Heridas realizadas en el dorso de ratas fueron revestidas con peliculas a base de colageno (G2) y con peliculas a base de colageno con propoleo rojo (G3), heridas sin revestimiento fueron utilizadas como control (G1). Despues de 3, 7 y 14 dias, las heridas fueron evaluadas microscopicamente. A los 7 dias G3 mostro un cambio del perfil de la respuesta inflamatoria de aguda a cronica, con aumento de la diferenciacion de las celulas plasmaticas, sustitucion de fibras de colageno tipo III por tipo I con mejora de la organizacion arquitectonica de estas fibras. Ademas, una ligera tendencia a una mejor epitelizacion se verifico en G3, pero no fue estadisticamente significativa. Tambien a los 7 dias, el conteo de microvasos fue mayor en G1 que en G2 (p=0,000) y G3 (p=0,001), pero similar entre los ultimos grupos (p=0,15), mientras que el perimetro de los microvasos fue mayor en G1 que en G2 (p=0,000) y G3 (p=0,002), pero equivalente en G2 y G3 (p=0,175) en 14 dias. En conclusion, la incorporacion de la variedad brasilena de propoleo rojo en peliculas a base de colageno fue capaz de mejorar la cicatrizacion de la herida, probablemente por la modulacion de la dinamica de la evolucion inflamatoria y del proceso de deposito de colageno.

Evaluation of anti-nociceptive and anti-inflammatory activity of low-level laser therapy on temporomandibular joint inflammation in rodents

The aim of this study was to investigate the analgesic and anti-inflammatory activity of low-level laser therapy (LLLT) on the nociceptive behavioral as well as histomorphological aspects induced by injection of formalin and carrageenan into the rat temporomandibular joint. The 2.5% formalin injection (FRG group) induced behavioral responses characterized by rubbing the orofacial region and flinching the head quickly, which were quantified for 45 min. The pretreatment with systemic administration of diclofenac sodium-DFN group (10 mg/kg i.p.) as well as the irradiation with LLLT infrared (LST group, 780 nm, 70 mW, 30 s, 2.1 J, 52.5 J/cm(2), GaAlAs) significantly reduced the formalin-induced nociceptive responses. The 1% carrageenan injection (CRG group) induced inflammatory responses over the time-course of the study (24 h, and 3 and 7 days) characterized by the presence of intense inflammatory infiltrate rich in neutrophils, scanty areas of liquefactive necrosis and intense interstitial edema, extensive hemorrhagic areas, and enlargement of the joint space on the region. The DFN and LST groups showed an intensity of inflammatory response that was significantly lower than in CRG group over the time-course of the study, especially in the LST group, which showed exuberant granulation tissue with intense vascularization, and deposition of newly formed collagen fibers (3 and 7 days). It was concluded that the LLLT presented an anti-nociceptive and anti-inflammatory response on the inflammation induced in the temporomandibular joint of rodents.

Potentiated anti-inflammatory effect of combined 780 nm and 660 nm low level laser therapy on the experimental laryngitis

Reflux laryngitis is a common clinic complication of nasogastric intubation (NSGI). Since there is no report concerning the effects of low level laser therapy (LLLT) on reflux laryngitis, this study aimed to analyze the protective effect of single and combined therapies with low level laser at the doses of 2.1J and 2.1+1.2 J with a total irradiation time of 30s and 30+30 s, respectively, on a model of neurogenic reflux laryngitis. NSGI was performed in Wistar rats, assigned into groups: NGI (no treatment), NLT17.5 (single therapy), and NLT17.5/10.0 (combined therapy, applied sequentially). Additional non-intubated and non-irradiated rats were use as controls (CTR). Myeloperoxidase (MPO) activity was assessed by colorimetric method after the intubation period (on days 1, 3, 5, and 7), whereas paraffin-embedded laryngeal specimens were used to carry out histopathological analysis of the inflammatory response, granulation tissue, and collagen deposition 7 days after NSGI. Significant reduction in MPO activity (p<0.05) and in the severity of the inflammatory response (p<0.05), and improvement in the granulation tissue (p<0.05) was observed in NLT17.5/10.0 group. Mast cells count was significantly decreased in NGI and NLT17.5 groups (p<0.001), whereas no difference was observed between NLT17.5/10.0 and CTR groups (p>0.05). NLT17.5/10.0 group also showed better collagenization pattern, in comparison to NGI and NLT17.5 groups. This study suggests that the combined therapy successfully modulated the inflammatory response and collagenization in experimental model of NSGI-induced neurogenic laryngitis.

Methylene Blue-Mediated Photodynamic Inactivation Followed by Low-Laser Therapy versus Miconazole Gel in the Treatment of Denture Stomatitis

PURPOSE Photodynamic therapy (PDT) appears to be an effective method for the in vitro and in vivo inactivation of Candida spp., but no clinical trials in this context have yet been conducted. The aim of this study was to compare the effect of oral miconazole gel to PDT combined with low-power laser (LPL) therapy in the treatment of denture stomatitis. MATERIALS AND METHODS Forty participants with clinical and microbiological diagnoses of type II denture stomatitis were randomly allocated to two treatment groups (PDT and miconazole gel), each with 20 individuals. The PDT group was submitted to one session of methylene blue-mediated PDT plus two sessions of low-laser therapy twice a week for 15 days. The miconazole group was submitted to the drug four times a day for 15 days. RESULTS Forty percent of the patients achieved clinical and microbiological resolution of denture stomatitis after methylene blue-mediated photodynamic inactivation followed by low-laser therapy. The cure rate associated with miconazole was 80% (p < 0.05). Fifteen days after the end of treatment, the recurrence rate was 25% in patients treated with PDT combined with LPL therapy and 12.5% in patients treated with miconazole. CONCLUSION Miconazole gel provides better results than a protocol combining methylene blue-mediated PDT and LPL therapy in the treatment of type II denture stomatitis.

Histological analysis of the periodontal ligament and alveolar bone during dental movement in diabetic rats subjected to low-level laser therapy

OBJECTIVE The purpose of this research was to evaluate the histological changes of the periodontal ligament and alveolar bone during dental movement in diabetic rats subjected to low level laser therapy (LLLT). METHODS The movement of the upper molar was performed in 60 male Wistar rats divided into four groups (n=15): CTR (control), DBT (diabetic), CTR/LT (irradiated control) and DBT/LT (irradiated diabetic). Diabetes was induced with alloxan (150 mg/kg, i.p.). LLLT was applied with GaAlAs laser at 780 nm (35 J/cm(2)). After 7, 13 and 19 days, the periodontal ligament and alveolar bone were histologically analyzed. RESULTS The mean of osteoblasts (p<0.01) and blood vessels (p<0.05) were significantly decreased in DBT compared with CTR at 7 days, whereas the mean of osteoclasts was lower at 7 (p<0.001) and 13 days (p<0.05). In DBT/LT, only the mean of osteoclasts was lower than in CTR (p<0.05) at 7 days, but no difference was observed at 13 and 19 days (p>0.05). The collagenization of the periodontal ligament was impaired in DBT, whereas DBT/LLT showed density/disposition of the collagen fibers similar to those observed in CTR. CONCLUSIONS LLLT improved the periodontal ligament and alveolar bone remodeling activity in diabetic rats during dental movement.

Analysis of Aloe vera cytotoxicity and genotoxicity associated with endodontic medication and laser photobiomodulation

This study aims to evaluate, in vitro, the effect of Aloe vera associated with endodontic medication, with or without laser photobiomodulation (FTL) irradiation in FP6 human pulp fibroblasts. The materials were divided into eight groups: CTR - control; CL - FTL alone; AA - Aloe vera with distilled water; AL - Aloe vera with distilled water and FTL; HA - calcium hydroxide P.A. with distilled water; HL - calcium hydroxide P.A. with distilled water and FTL; HAA - calcium hydroxide P.A. with Aloe vera and distilled water; HAL - calcium hydroxide P.A. with Aloe vera, distilled water, and FTL. The cytotoxicity was evaluated by MTT assay at 24, 48, and 72h and the genotoxicity by micronucleus test assay. This study was performed in triplicate. Data obtained in both tests were statistically analyzed by ANOVA and Tukeys tests (p≤0.05). Group AA presented high genotoxicity and low cytotoxicity. After 24, 48, and 72h, the group HAA significantly reduced the cell viability. Interaction with FTL showed slightly increase cell viability after 24 and 48h in groups CL and HL (p<0.001), despite the high genotoxicity in group CL and low genotoxicity in group HL. Group AL showed higher cell survival rate at 72h (p<0.05) and high genotoxicity (p<0.001). It was concluded that Aloe vera allowed higher cell viability in human pulp fibroblasts in the presence of calcium hydroxide or with FTL separately, but genotoxicity increased in these associations.

Tooth color change caused by photosensitizers after photodynamic therapy: An in vitro study☆☆☆☆☆☆☆☆☆☆

This study aimed to perform an in vitro evaluation of the effect of photosensitizers used in photodynamic therapy (PDT) on tooth color change when used in combination with conventional endodontic treatment. Forty extracted human mandibular premolars were accessed and underwent root canal therapy and PDT. Photosensitizers were used in accordance with the experimental groups: MB (n=10) - PDT with Methylene Blue at 0.01%; TB (n=10) - PDT with Toluidine Blue at 0.01%; MG (n=10) - PDT with Malachite Green at 0.01%, at the concentration of 0.1mg/mL; and PC (n=10) - positive control, PDT with Endo-PTC cream stained with Methylene Blue at 25%. The samples were irradiated with 660-nm diode laser by means of a 330-μm-diameter optical fiber cable at a power density of 40mW for 120s. After light curing, the photosensitizers were removed from the specimens with 10mL sodium hypochlorite at 1%. A reflectance spectrometer was used for evaluation of color prior to and 60days after the experimental procedure based on the CIE L*a*b* system. According to ANOVA test, there were statistically significant differences between the experimental groups (p=0.003). Tukeys test showed a significant difference between PC and TB (p=0.008), as well as between MG and TB (p=0.009). However, there was no statistically significant difference between PC, MG (p=0.957) and MB (p=0.103). It was concluded that the use of PDT as an adjuvant to root canal therapy, using different photosensitizers, led to color change in tooth structure.