Histological evaluation of skin lesions induced by Leishmania braziliensis treated by PACT using Laser light and 1.9 dimethyl-methylene blue.

This study aimed to perform a histological evaluation in skin lesions caused by Leishmania braziliensis after PACT treatment using Laser associated with 1.9. dimethyl methylene blue BALB/c mouse ear infection model was used. A total of 40 animals were assigned into two groups considering time intervals at 5 and 10 weeks and subdivided into four subgroups: Control, Photosensitizer, Laser and PACT. Two therapeutic interventions were performed after the 5th week of infection at 48 h intervals. 1.9 Dimethyl methylene blue was used as a photosensitizer at the concentration of 7 ng/mL, with a non-invasive topical administration method associated with Laser (λ = 660 nm, 40 mW, 12 J/cm2). Sample collection occurred 5 or 10 weeks after therapeutic interventions. The main histological findings were observed in the laser and PACT groups at the 10-week evaluation. The Laser group showed reduced lymphoplasmacytic inflammation and histiocytes (p = 0.0079). The PACT group showed reductions in lymphoplasmacytic inflammation at 5 and 10 weeks, discrete reduction of histiocytes and a higher percentage of tissue remodeling. PACT with non-invasive topical administration of the photosensitizer was able to reduce lymphoplasmacytic inflammation and increase tissue remodeling in leishmaniosis skin lesions. This protocol may be easily used in humans and clinical trial shall be carried out to confirm the animal's findings.

Glypican-1, -3, -5 (GPC1, GPC3, GPC5) and Hedgehog Pathway Expression in Oral Squamous Cell Carcinoma.

Proteoglycans are involved in tumor development and may regulate the Hedgehog (HH) pathway. This study aimed to investigate the gene and protein expression of glypican-1 (GPC1), -3 (GPC3), and -5 (GPC5) in oral squamous cell carcinoma (OSCC) and tumor-free lateral margins (TM) and their association with the HH pathway. Quantitative PCR was performed for GPC1, GPC3, GPC5, SHH, PTCH1, SMO, and GLI1 genes in samples of OSCC (n=31), TM (n=12), and non-neoplastic oral mucosa (NNM) of healthy patients (n=6), alongside an immunohistochemical evaluation of GPC1, GPC3, and GPC5 proteins and HH proteins SHH and glioma-associated oncogene homolog 1 (GLI1). Double staining for GPC3/SHH, GPC5/SHH, GPC3/tubulin [ac Lys40], GPC5/Tubulin [ac Lys40], and GPC5/GLI1 was also performed. Overexpression of GPC1 and GPC5 in tumor samples and underexpressed levels of GPC3 gene transcripts were observed when compared with TM (standard sample). HH pathway mRNA aberrant expression in OSCC samples and a negative correlation between GPC1 and GPC5 at transcription levels were detected. GPC1 staining was rare in OSCC, but positive cells were found in NNM and TM. Otherwise positive immunostaining for GPC3 and GPC5 was observed in OSCCs, but not in NNM and TM. Blood vessels adjacent to tumor islands were positive for GPC1 and GPC5. Co-localization of GPC3-positive and GPC5-positive cells with SHH and Tubulin [ac Lys40] proteins was noted, as well as of GPC5 and GLI1. The absence of the GPC1 protein in neoplastic cells, underexpression of the GPC3 gene, and co-localization of GPCs and HH proteins may indicate the maintenance of aberrant HH pathway activation in OSCC.

Immunodetection of Epithelial-Mesenchymal Transition and Tumor Proliferation Markers in GLi-1-positive Oral Squamous Cell Carcinoma.

In oral squamous cell carcinoma (OSCC), involvement and activation of the Hedgehog pathway (HH) may be related to epithelial-mesenchymal transition and cell proliferation. The present study aimed to evaluate epithelial-mesenchymal transition and proliferative potential in OSCC cases demonstrating activation of the HH pathway. Twenty-three GLi-1-positive OSCC cases were submitted to immunohistochemical detection of Snail, Slug, N-cadherin, E-cadherin, ß-catenin, and MCM3 proteins. Clinical-pathologic immunoexpression data were obtained from the invasion front and tumor islets, and then compared. At the invasion front, OSCC cases presented positive Snail, Slug, and MCM3 expression in the nuclei of tumor cells. Loss of membrane and cytoplasmic expression of E-cadherin and ß-catenin was also observed. Positive N-cadherin expression was observed in 31.78% of the cases. GLi-1 immunoexpression was associated with loss of membrane E-cadherin (P<0.001), membrane ß-catenin (P<0.001), and cytoplasmic ß-catenin (P=0.02) expression. In the tumor islets, we observed nuclear expression of GLi-1, Snail, Slug, and MCM3. E-cadherin and ß-catenin showed positivity in tumor cell membranes. Statistically significant positive correlations between GLi-1 and Snail (P=0.05), E-cadherin (P=0.01), and cytoplasmic ß-catenin (P=0.04) were found. GLi-1 was associated with clinical staging, while membrane ß-catenin expression was related to the presence of metastasis in lymph nodes and to clinical staging. The HH pathway may be involved in regulating the expression of the mesenchymal phenotype. The loss of membrane E-cadherin and ß-catenin expression was observed at the tumor front region, whereas cell adhesion protein expression was detected in tumor islets regardless of MCM3.

Association between alcohol dependence and both periodontal disease and tooth loss: a cross-sectional study.

The impact of alcohol consumption on periodontal disease and tooth loss is still under debate. The aim of this cross-sectional study was to evaluate the association between alcohol dependence and both periodontal diseases and tooth loss in Brazilian native Indians. Full mouth periodontal examination was performed and tooth loss was clinically evaluated in a representative sample of 225 Indians (≥ 19 years). Sociodemographic, oral health-related data, and alcohol dependence were evaluated using structured questionnaires. The subjects were categorized as either alcohol-dependent or non-dependent according to the Alcohol Use Disorders Identification Test results. Severe periodontal disease was defined in individuals with ≥ 2 proximal sites with a clinical attachment level ≥ 6 mm, not on the same tooth, and ≥ 1 proximal site with a probing depth ≥ 5 mm. Tooth loss was categorized as one or more missing teeth, or no missing teeth. Bivariate models followed by logistic regression were used to assess the association between alcohol dependence and both periodontal disease and tooth loss. Prevalence ratio (PR) was calculated using Mantel-Haenszel analysis. Alcohol dependence increased 2.5 times the risk for tooth loss (prevalence ratio [PR] =2.49, 95% confidence interval [CI] = 1.01-9.04, p = 0.05). Severe periodontal disease was not associated with alcohol dependence (OR = 0.54, 95% CI = 0.22-1.31, p = 0.23). In conclusion, alcohol dependence was associated with tooth loss in the present population, but severe periodontal disease was not. Questions on alcohol dependence should be included in dental anamnesis questionnaires, and patients diagnosed with alcohol dependence should be referred for dental evaluation.

Association Between Mast Cells and Collagen Maturation in Chronic Periodontitis in Humans.

Mast cells (MCs) can influence the maturation of collagen fibers. This study evaluated the relationship between the distribution and degranulation of MCs and collagen maturation in human gingival tissue in chronic periodontitis. A total of 16 specimens of patients clinically diagnosed as periodontitis and 18 controls clinically diagnosed as healthy or gingivitis were included. Immunohistochemistry and Picrosirius staining were performed to identify MCs and assess collagen fibers, respectively. Chi-square, t test, and Pearson's correlation test ( p<0.05) were used. In control specimens, there was a positive association between MCs in the connective tissue and the presence of immature collagen ( p=0.001); in periodontitis samples, this association was not confirmed ( p≥0.12). There was no significant relationship between periodontal diagnosis and collagen maturation or MC degranulation ( p≥0.35). MC density was significantly higher ( p=0.04) in periodontitis tissue (339.01 ± 188.94 MCs/mm2) than in control tissue (211.14 ± 131.13 MCs/mm2) in the area of connective tissue containing inflammatory infiltrate. There was a correlation between the number of MCs and probing depth ( r = 0.34, p=0.04). MCs are involved in the pathogenesis of periodontal diseases and might be associated with collagen maturation in periodontal tissue during the early stages of periodontal disease pathogenesis.

MCM3: A Novel Proliferation Marker in Oral Squamous Cell Carcinoma.

The present study sought to evaluate and compare the immunoexpression of proteins minichromosome maintenance (MCM) 3 and Ki-67 in oral squamous cell carcinoma (OSCC) to assess the potential of these proteins as markers of cellular proliferation. Twenty-eight cases of OSCC, 9 of tumor-free resection margins (TM), and 4 of non-neoplastic oral mucosa (NNM) were subjected to immunohistochemistry to detect the expression of proteins MCM3 and Ki-67. All OSCCs demonstrated positivity for both proteins. In these tumors, greater MCM3 immunoreactivity was observed in comparison with Ki-67, whereas TMs and NNMs exhibited greater Ki-67 expression compared with MCM3. The immunoexpression of Ki-67 seemed to be influenced by the inflammatory process, particularly in TM and NNM. Our findings indicate that although both MCM3 and Ki-67 represent reliable markers of cellular proliferation in OSCC, as MCM3 expression does not appear to be influenced by external factors, this protein may emerge as a novel marker of cellular proliferation in these types of tumors.

Immunohistochemical Characterization of Cancer-associated Fibroblasts in Oral Squamous Cell Carcinoma.

Myofibroblasts are differentiated contractile cells that can secrete extracellular matrix components, cytokines, proteases, and proangiogenic factors. In neoplastic processes such as oral squamous cell carcinoma (OSCC), myofibroblasts are recognized as cancer-associated fibroblasts (CAFs) and actively participate in tumor progression. As the presence of myofibroblasts in the stroma may be an important parameter of invasion and proliferation, the aim of this study was to evaluate the presence of CAFs in OSCC by immunophenotyping and their association with histologic classification and clinicopathologic parameters. A total of 34 formalin-fixed, paraffin-embedded samples of OSCC were analyzed for CAF histology and immunophenotype established on the basis of the simultaneous immunohistochemical expression of α-SMA, fibronectin, FSP1, HHF35, and vimentin. According to the histologic classification of CAFs, 16 (47%) cases were classified as the mature subtype and 18 (53%) as the immature subtype. CAF immunophenotype was detected in 19 (56%) cases, and the immunophenotype was variable in 15 (44%) cases. The CAFs immunophenotype was significantly associated with the immature histologic subtype. Immunohistochemical expression of α-SMA, fibronectin, FSP1, HHF35, and vimentin represents a suitable CAF immunophenotype in OSCC. The CAF immunophenotype is associated with the immature histologic subtype. The characterization of CAFs may identify tumors with a distinct biological profile in OSCC. Studies extending the investigation of CAFs to OSCC are needed to determine the actual role of this cell population as a possible prognostic marker.

Evaluation of Mast Cell Density in the Tumor Microenvironment in Oral Epithelial Dysplasia and Oral Squamous Cell Carcinoma.

The objective of this study was to compare mast cell density (MCD) in oral epithelial dysplasias (OED) and oral squamous cell carcinoma (OSCC) and determine its correlation with clinical and histopathologic parameters and the degree of tumor differentiation. Thirty OSCC samples, 14 OED samples, and 4 non-neoplastic oral mucosa samples were analyzed by immunohistochemistry to determine MCD based on the expression of MC tryptase. In addition, MCs were categorized morphologically into degranulated and granulated cells. MCD was significantly higher in OSCC lesions with a greater degree of differentiation (P=0.04). No significant difference in MCD was detected between mild and moderate OED samples (P=0.09). Our findings indicate that MCs are present in the tumor microenvironment and may be associated with a better prognosis.

Dental health status in crack/cocaine-addicted men: a cross-sectional study.

The aim of this study was to evaluate the association between crack/cocaine addiction and dental health in men. Forty crack/cocaine-addicted patients and 120 nonaddicted patients (≥18 years) underwent full-mouth dental examinations. Decayed, missing, and filled teeth (DMFT) were identified using the criteria recommended by the World Health Organization. Crack/cocaine addiction was determined, based on the medical records and interviews of each patient. All drug-addicted patients used both crack and cocaine. The chi-square test and logistic regression analysis were used to assess the association between DMFT and crack/cocaine addiction (p ≤ 0.05). Decayed teeth showed a positive association with crack/cocaine addiction (odds ratio (OR) = 3.65; 95% confidence interval (CI), 1.68-7.92; p = 0.001), whereas filled and missing teeth showed a negative association (filled teeth: OR = 0.37; 95% CI, 0.18-0.76; p = 0.008; missing teeth: OR = 0.33; 95% CI, 0.13-0.81; p = 0.02). The DMFT was only associated with age (OR = 2.12; 95% CI, 1.11-4.08, p = 0.023). In the present population, crack/cocaine addiction was associated with a greater decayed teeth index and a lower filled and missing teeth index. Programs aimed to encourage self-esteem and encourage individuals to seek dental care are required for this population. Further studies using a larger sample size and studies with women are required to confirm the results.

Immunohistochemical Study of TGF-ß1 in Oral Leukoplakia and Oral Squamous Cell Carcinoma: Correlations Between Clinicopathologic Factors and Overall Survival.

The aim of the present study was to analyze transforming growth factor ß1 (TGF-ß1) expression in cases of leukoplakia and oral squamous cell carcinoma (OSCC) and to correlate these expression profiles with proliferative labeling index, clinicopathologic factors, and clinical outcome. Clinical data for 24 cases of leukoplakia and 87 cases of OSCC were retrieved from medical records. OSCC tissues were included into tissue microarray blocks and sections of normal mucosa, leukoplakia, and OSCC tissue microarray's were prepared on slides. Immunohistochemistry was used to detect expression of TGF-ß1 and Ki67. The expression of TGF-ß1 and Ki67 were significantly increased from normal mucosa, through leukoplakia to OSCC. High expression of TGF-ß1 correlated with an increase in proliferative labeling index. No association between TGF-ß1 expression and the clinicopathologic factors examined was observed. Expression of TGF-ß1 also did not associate with clinical outcome in either of groups. Our results suggest that changes in TGF-ß1 are associated with the progression of oral carcinogenesis.

Ameloblastic carcinoma: a Brazilian collaborative study of 17 cases.

AIMS: Ameloblastic carcinoma (AMECA) is an odontogenic malignancy that combines the histological features of ameloblastoma and cytological atypia. Because of its rarity, it poses difficulties in diagnosis. The aim of this study was to investigate the socio-demographic data, histopathology, immunohistochemical features, treatment and outcomes of 17 cases. METHODS AND RESULTS: Descriptive statistical analyses were used to portray the clinicopathological data collected, retrospectively. Log-rank tests were performed to determine new prognostic factors. Lesions were immunostained for Ki67, p16, p53, and cytokeratins (CKs), and compared with solid/multicystic ameloblastomas (n = 15). AMECA was mostly diagnosed at a late stage, affecting the posterior mandible of male patients in their fifth decade of life. Recurrence was diagnosed in nearly 90% of treated patients, and metastasis occurred in four patients. The mean number of Ki67-positive cells was 86.4 ± 66 per field. Tumours were focally positive for CK7, CK8, CK14, and CK18, and diffusely positive for CK19, p53, and p16. AMECA showed increased immunoexpression of CK18, CK19, p16, p53 and Ki67 as compared with benign cases. CONCLUSIONS: Our study has contributed to the improved characterization of the epidemiology, prognostic markers, treatment options and outcomes of AMECA. Current criteria must be reviewed to simplify the diagnostic process for these neoplasms.

Risk indicators for tooth loss in Kiriri Adult Indians: a cross-sectional study.

BACKGROUND: The aim of this cross-sectional study was to evaluate the risk indicators of tooth loss in adult Kiriri Indians from Brazil. METHODS: A representative sample of 225 Indians (≥ 19 years of age) was assessed. Interviews using a structured written questionnaire were performed to collect data on demographics and socio-economic status, and health-related data. Probing depth, the distance between the cement-enamel junction and the free gingival margin, and decayed, missing or filled teeth were evaluated. Bivariate and logistic models were used to assess associations between tooth loss and age, sex, income, education, diabetic status, smoking habits, dental caries, severe periodontitis, plaque index and previous dental visit. RESULTS: Eighty per cent of subjects had lost one tooth or more, and 20% had lost eight teeth or more. Mean (± standard deviation) tooth loss was 5.09 (± 5.83) teeth. After adjustment for covariates, loss of one tooth or more was associated with older age [≥ 35 years; odds ratio (OR) = 4.06, 95% confidence interval (95% CI): 1.38-11.94, P = 0.01], severe periodontitis (OR = 3.35, 95% CI: 0.99-11.24, P = 0.05), higher dental caries (OR = 3.24, 95% CI: 1.35-7.78, P = 0.01) and previous dental visit (OR = 23.32, 95% CI: 5.75-94.63, P < 0.001). CONCLUSION: Tooth loss is highly prevalent in Kiriri Indians. Older age, severe periodontitis, higher caries index and previous dental visit were associated with tooth loss. Prevention and treatment programmes, targeting high-risk groups, are required to promote the oral health of the population.

Assessment of different energy delivery settings in laser and LED phototherapies in the inflammatory process of rat's TMJ induced by carrageenan.

Temporomandibular disorders (TMDs) are mostly inflammatory conditions widespread in the population. Previous studies have shown positive effects of either laser or light-emitting diode (LED) phototherapies on treating TMDs, but their action and mechanism in the inflammatory infiltrate of the temporomandibular joint are still poorly understood. The aim of this study was to assess, through histological analysis, the effectiveness of using laser light (λ 780 nm, 70 mW, continous wave (CW), 10 J) and LED (λ 850 ± 10 nm, 100 mW, CW, 10 J) on the inflammation of the temporomandibular joint of rats induced by carrageenan. Forty-five animals were divided into three groups with five animals each according to the experimental times of 2, 3, and 7 days: inflammation, inflammation+laser phototherapy, and inflammation+LED phototherapy. The first irradiation was performed 24 h after induction with an interval of 48 h between sessions. After animal death, specimens were processed and stained with hematoxylin-eosin (HE) and picrosirius. Then, the samples were examined histologically. Data were statistically analyzed. The inflammation group showed mild to moderate chronic inflammatory infiltrate between bone trabecules of the condyle. Over the time course of the study in the laser group, the region of the condyle presented mild chronic inflammation and intense vascularization. In the LED group, the condyle showed aspects of normality and absence of inflammation in some specimens. In all the time points, the laser-irradiated groups showed greater amount of collagen deposition in the condyle (p = 0.04) and in the disc (p = 0.03) when compared to the inflammation and LED groups, respectively. Laser- and LED-treated groups demonstrate a smaller number of layers of the synovial membrane when compared to the non-irradiated groups. It was concluded that, in general, laser and LED phototherapies resulted in a reduction of inflammatory infiltrate in the temporomandibular joint of rat.

Does LED phototherapy influence the repair of bone defects grafted with MTA, bone morphogenetic proteins, and guided bone regeneration? A description of the repair process on rodents.

This work carried out a histological analysis on bone defects grafted (MTA) treated or not with LED, BMPs, and membrane (GBR). Benefits of their isolated or combined usage on bone repair were reported, but not their association. Ninety rats were divided into ten groups and each subdivided into three. Defects on G II and I were filled with the blood clot. G II was further LED irradiated. G III and IV were filled with MTA; G IV was further LED irradiated. In G V and VI, the defects were filled with MTA and covered with a membrane (GBR). G VI was further LED irradiated. In G VII and VIII, BMPs were added to the MTA and group VIII was further LED irradiated. In G IX and X, the MTA + BMP graft was covered with a membrane (GBR). G X was further LED irradiated. LED was applied over the defect at 48-h intervals and repeated for 15 days. Specimens were processed, cut, and stained with H&E and Sirius red and underwent histological analysis. The use of LED light alone dramatically reduced inflammation. However, its use on MTA associated with BMP and/or GBR increased the severity of the inflammatory reaction. Regarding bone reabsorption, the poorest result was seen when the LED light was associated with the MTA + BMP graft. In the groups Clot and MTA + GBR, no bone reabsorption was detectable. Increased collagen deposition was observed when the LED light was associated with the use of the MTA associated with BMP and/or GBR. Increased new bone formation was observed when the LED light was used alone or associated with the use of MTA + GBR, MTA + BMP, on association of MTA + BMP + GBR and when BMP was added to the MTA. Our results indicate that the use of LED light alone or in association with MTA, MTA + BMP, MTA + GBR, and MTA + BMP + GBR caused less inflammation, and an increase of both collagen deposition and bone deposition as seen on both histological and morphometric analysis.

Light microscopic description of the effects of laser phototherapy on bone defects grafted with mineral trioxide aggregate, bone morphogenetic proteins, and guided bone regeneration in a rodent model.

We carried out a histological analysis on bone defects grafted with mineral trioxide aggregate (MTA) treated or not with laser, bone morphogenetic protein (BMP), and guided bone regeneration (GBR). Benefits of the use of MTA, laser, BMPs, and GBR on bone repair are well known, but there is no report on their association with laser light. Ninety rats were divided into 10 groups each subdivided into 3. Defects on G II and I were filled with the blood clot. G II was further irradiated with LED. G III and IV were filled with MTA; G IV was further irradiated with laser. G V and VI, the defects filled with MTA and covered with a membrane (GBR). G VI was further irradiated with laser. G VII and VIII, BMPs were added to the MTA and group VIII further irradiated with laser. G IX and X, the MTA + BMP graft was covered with a membrane (GBR). G X was further irradiated with laser. Laser light (λ = 850 nm, 150 mW, 4 J/cm(2) ) was applied over the defect at 48-h intervals and repeated for 15 days. Specimens were processed, cut and stained with H&E and Sirius red and underwent histological analysis. Subjects on group X were irradiated. The results showed different tissue response on all groups during the experimental time. Major changes were seen on irradiated subjects and included marked deposition of new bone in advanced maturation. It is concluded that near infrared laser phototherapy improved the results of the use of the MTA on bone defects.

Evaluation of laser phototherapy in the inflammatory process of the rat's TMJ induced by carrageenan.

AIM: The aim of this study was to evaluate, by light microscopy, the effects of laser phototherapy (LPT) at 780 nm or a combination of 660 and 790 nm, on the inflammatory process of the rat temporomandibular joint (TMJ) induced by carrageen. BACKGROUND: Temporomandibular disorders (TMDs) are frequent in the population and generally present an inflammatory component. Previous studies have evidenced positive effects of laser phototherapy on TMDs. However, its mechanism of action on the inflammation of the TMJ is not known yet. MATERIALS AND METHODS: Eighty-five Wistar rats were divided into 9 groups: G1, Saline; G2, Saline + LPT IR; G3, Saline + LPT IR + R; G4, Carrageenan; G5, Carrageenan + LPT IR; G6, Carrageenan + LPT IR + R; G7, previous LPT + Carrageenan; G8, previous LPT + carrageenan + LPT IR; and G9, previous LPT + carrageenan + LPT IR + R, and then subdivided in subgroups of 3 and 7 days. After animal death, specimens were taken, routinely cut and stained with HE, Sirius Red, and Toluidine Blue. Descriptive analysis of components of the TMJ was done. The synovial cell layers were counted. RESULTS: Injection of saline did not produced inflammatory reaction and the irradiated groups did not present differences compared to nonirradiated ones. After carrageenan injection, intense inflammatory infiltration and synovial cell layers proliferation were observed. The infrared irradiated group presented less inflammation and less synovial cell layers number compared to other groups. Previous laser irradiation did not improve the results. CONCLUSION: It was concluded that the LPT presented positive effects on inflammatory infiltration reduction and accelerated the inflammation process, mainly with IR laser irradiation. The number of synovial cell layers was reduced on irradiated group.

Influence of the combination of infrared and red laser light on the healing of cutaneous wounds infected by Staphylococcus aureus.

AIM: We aimed to assess the use of two wavelengths on the healing of infected wounds. BACKGROUND: Infection is the most significant cause of impaired wound repair or healing. Several therapeutic approaches are used for improving wound healing including the use of different light sources, such as the laser. Some wavelengths yield positive photobiological effects on the healing process. MATERIAL AND METHODS: The backs of 24 young adult male Wistar rats under general anesthesia were shaved and cleaned, and a 1 by 1 cm cutaneous wound was created with a scalpel and left untreated. The wounds were infected with Staphylococcus aureus, and the rats were randomly divided into two sets of four subgroups with three animals in each subgroup: control, red laser light, infrared laser light, and red + infrared laser light. Laser phototherapy was carried out with a diode [λ680 nm/790 nm, power (P) = 30 mW/40 mW, continuous wave laser, Ø = 3 mm, power density (P) = 424 and 566 mW/cm(2), time = 11.8/8.8 sec, E = 0.35 J] and started immediately after surgery and repeated every other day for 7 d. Laser light was applied on four points around the wounded area (5 J/cm(2)). The animals were killed either 8 or 15 d after contamination. Specimens were taken, embedded in paraffin, and sectioned and stained for histological analysis. RESULTS: Histological analysis showed that control subjects had a lower amount of blood vessels when compared with irradiated subjects. Irradiated subjects had more advanced resolution of inflammation compared with controls. Irradiated subjects also showed a more intense expression of the collagen matrix. The collagen fibers were mostly mature and well organized in these subjects at the end of the experimental time especially when both wavelengths were used. CONCLUSION: The results of the present study indicate that laser phototherapy has a positive effect on the healing of infected wounds, particularly with the association of λ680 + λ790 nm.

Assessment of the effect of the use of laser light or dantrolene on facial muscle under occlusal wear: a Raman spectroscopic study in a rodent model.

OBJECTIVE: The aim of the present study was to use Raman spectroscopy to measure levels of CaPi in muscles under occlusal wear and treated with laser phototherapy (LPT) or muscle-relaxant therapy or both on rodents. BACKGROUND: The etiology of temporomandibular disorders is multifactorial. Malocclusion may influence the masticatory muscles, causing fatigue. A major type of fatigue is the metabolic, caused by the increased accumulation of metabolites such as inorganic phosphate. Raman spectroscopy allows nondestructive analysis of the biochemical composition of tissues. METHODS: The 30 male Wistar rats were randomly divided into three groups: occlusal wear (G-1), occlusal wear + LPT (G-2), and occlusal wear + muscle relaxant (G-3). Ten untreated animals were used for baseline data. Under intraperitoneal general anesthesia, animals of groups 1, 2, and 3 had unilateral amputation of molar cusps to simulate an occlusal-wear situation. The masseter muscle of G-2 received LPT (lambda830 nm, 4 J/cm(2), 40 mW, phi approximately 2 mm) after the procedure and repeated every other day for 14-30 days. Animals of G-3 were treated with a daily injection of dantrolene (2.5 mg/kg in 0.5 ml of H(2)O) beginning 24 h after cusp removal. Animals were killed with an overdose of general anesthetics at days 14 and 30 after cusps removal, and the ipsilateral masseter muscle was excised and divided into two parts. One part was routinely processed and underwent histologic analysis; the other was kept in liquid nitrogen for Raman spectroscopy. The mean value of the intensity of the peak 958 per centimeter was determined. RESULTS: No morphologic changes were seen. Raman analysis showed significantly less Raman intensity in the laser group at 30 days (p < 0.01). CONCLUSION: Occlusal wear did not caused morphologic alterations in the masseter muscle but resulted in changes of the levels of CaP(i) that were less compromising when the laser light was used.

Effects of laser photobiomodulation on cutaneous wounds treated with mitomycin C: a histomorphometric and histological study in a rodent model.

AIM: The aim of the present study was to assess histologically the effect of Laser Photobiomodulation (LPBM) on skin wounds treated with Mitomycin C (MMC). BACKGROUND DATA: Wound healing occurs because of a competitive mechanism between the synthesis and lyses of collagen. Therefore, any factor that increases the lyses or reduces the synthesis of collagen may result in changes in the healing process. MMC is an antineoplastic drug that inhibits fibroblast proliferation, collagen synthesis, and neoangiogenesis. LPBM has been shown to stimulate wound healing, increasing the production of collagen, fibroblastic proliferation, and angiogenesis. MATERIALS AND METHODS: Forty-eight Wistar rats were randomly distributed into 4 main groups (n = 12): G1--control (G1a--7 d and G1b--14 d); G2--MMC (G2a--7 d and G2b--14 d); G3--MMC + lambda660 nm laser (G3a--7 d and G3b--14 d); and G4--MMC + lambda790 nm laser (G4a--7 d and G4b--14 d). Under general anesthesia, one excisional wound was created on the dorsum of each animal. Two ml of MMC solution was applied to the wound 4 h after surgery for 5 min. LPBM was performed on groups G3 (lambda690 nm; 20 J/cm(2); 30 mW; Phi = 2 mm) and G4 (lambda790 nm; 20 J/cm(2); 40 mW; Phi = 2 mm), starting immediately after the application of the MMC and repeated every other day during the experimental period. Laser light was applied transcutaneously at 4 equidistant points on the wound margin (4 x 5 J/cm(2), 20 J/cm(2)/session). The specimens were routinely cut and processed to wax. The slides were stained with HE and Sirius red. Computerized hystomorphometry was performed. RESULTS: LPBM resulted in reduced inflammation and an increase in both fibroblast proliferation and collagen deposition. CONCLUSION: The use of LPBM improves wound healing in subjects treated with MMC.

Influence of the use of laser phototherapy (lambda660 or 790 nm) on the survival of cutaneous flaps on diabetic rats.

OBJECTIVE: The aim of this study was to assess and compare the effects of laser phototherapy (LPT) on cutaneous flaps on diabetic rats. BACKGROUND: Diabetes mellitus is characterized by high blood glucose levels. Its main complications are delayed wound healing, an impaired blood supply, and a decrease in collagen production. Cutaneous flaps are routinely used in several surgical procedures, and most failures are related to poor blood supply. LPT has been studied using several healing models. ANIMALS AND METHODS: Twelve Wistar rats were randomized into three groups: group 1 (G1; diabetic animals without treatment), group 2 (G2; diabetic animals irradiated with lambda680 nm), and group 3 (G3; diabetic animals irradiated with lambda790 nm). Diabetes was induced with streptozotocin. A 2- x 8-cm cutaneous flap was raised on the dorsum of each animal, and a plastic sheet was introduced between the flap and the bed to cause poor blood supply. Nonirradiated animals acted as controls. The dose per session was 40 J/cm(2). Laser light was applied transcutaneously and fractioned on 16 contact points at the wound margins (16 x 2.5 J/cm(2)). Animal death occurred on day 8 after surgery. Specimens were taken, processed, cut, stained with eosin (HE) and sirius red, and underwent histological analysis. RESULTS: It is shown that accute inflammation was mostly discrete for G3. Chronic inflammation was more evident for G2. Fibroblast number was higher for G3. Angiogenesis was more evident for G3. Necrosis was more evident for G2. Statistical analysis among all groups showed significant differences (p = 0.04) on the level of acute inflammation between G1 and G3, tissue necrosis between G1 and G2 (p = 0.03), chronic inflammation between (p = 0.04), fibroblastic proliferation between G2 and G3 (p = 0.05), and neovascularization between G2 and G3 (p = 0.04). CONCLUSION: LPT was effective in increasing angiogenesis as seen on irradiated subjects and was more pronounced when IR laser light was used.