Engineering models of head and neck and oral cancers on-a-chip.

Head and neck cancers (HNCs) rank as the sixth most common cancer globally and result in over 450 000 deaths annually. Despite considerable advancements in diagnostics and treatment, the 5-year survival rate for most types of HNCs remains below 50%. Poor prognoses are often attributed to tumor heterogeneity, drug resistance, and immunosuppression. These characteristics are difficult to replicate using in vitro or in vivo models, culminating in few effective approaches for early detection and therapeutic drug development. Organs-on-a-chip offer a promising avenue for studying HNCs, serving as microphysiological models that closely recapitulate the complexities of biological tissues within highly controllable microfluidic platforms. Such systems have gained interest as advanced experimental tools to investigate human pathophysiology and assess therapeutic efficacy, providing a deeper understanding of cancer pathophysiology. This review outlines current challenges and opportunities in replicating HNCs within microphysiological systems, focusing on mimicking the soft, glandular, and hard tissues of the head and neck. We further delve into the major applications of organ-on-a-chip models for HNCs, including fundamental research, drug discovery, translational approaches, and personalized medicine. This review emphasizes the integration of organs-on-a-chip into the repertoire of biological model systems available to researchers. This integration enables the exploration of unique aspects of HNCs, thereby accelerating discoveries with the potential to improve outcomes for HNC patients.

Engineering pericyte-supported microvascular capillaries in cell-laden hydrogels using stem cells from the bone marrow, dental pulp and dental apical papilla.

Engineered tissue constructs require the fabrication of highly perfusable and mature vascular networks for effective repair and regeneration. In tissue engineering, stem cells are widely employed to create mature vascularized tissues in vitro. Pericytes are key to the maturity of these vascular networks, and therefore the ability of stem cells to differentiate into pericyte-like lineages should be understood. To date, there is limited information regarding the ability of stem cells from the different tissue sources to differentiate into pericytes and form microvascular capillaries in vitro. Therefore, here we tested the ability of the stem cells derived from bone marrow (BMSC), dental pulp (DPSC) and dental apical papilla (SCAP) to engineer pericyte-supported vascular capillaries when encapsulated along with human umbilical vein endothelial cells (HUVECs) in gelatin methacrylate (GelMA) hydrogel. Our results show that the pericyte differentiation capacity of BMSC was greater with high expression of α-SMA and NG2 positive cells. DPSC had α-SMA positive cells but showed very few NG2 positive cells. Further, SCAP cells were positive for α-SMA while they completely lacked NG2 positive cells. We found the pericyte differentiation ability of these stem cells to be different, and this significantly affected the vasculogenic ability and quality of the vessel networks. In summary, we conclude that, among stem cells from different craniofacial regions, BMSCs appear more suitable for engineering of mature vascularized networks than DPSCs or SCAPs.

The effects of photodynamic therapy with blue light and papain-based gel associated with Urucum, on collagen and fibroblasts: a spectroscopic and cytotoxicity analysis.

Papacarie Duo™ is clinically used and has proven effectiveness; however, it is necessary to improve its antimicrobial action. The combined treatment of Papacarie Duo™ with Urucum (Bixa Orellana) could create a potential tool for dental caries treatment; its extract obtained from the seeds' pericarp contains a water-soluble primary pigment (cis-bixin) with smaller amounts of other carotenoids. The dicarboxylic acid salts of cis-norbixin and trans-norbixin occur in heated alkaline solutions. To analyze the absorption spectra and cytotoxicity (with human dermal fibroblasts) in different concentrations of Urucum, associated or not with Papacarie Duo™, we performed this in vitro study. The effects of pure Urucum, Papacarie Duo™, and PapaUrucum™ on the microstructure of collagen were also analyzed. The application of papain-based gel with Urucum did not present cytotoxicity, its exhibit UV absorption spectrum peak around 460 ± 20 nm. Also, it showed that the compound used did not alter the chemical structure of collagen. Consequently, this product could be used as a chemomechanical method to remove dentin caries as well as being a potential product for antimicrobial photodynamic therapy (aPDT) application.

Modulating effect of low intensity pulsed ultrasound on the phenotype of inflammatory cells.

AIMS: The purpose of this study was toclarify the effect of low intensity pulsed ultrasound (LIPUS) on the phenotype of the inflammatory infiltrate in muscle tissue following acute injury. MAIN METHODS: Forty Wistar rats were submitted to cryoinjury of the tibialis anterior muscle and only half were treated with LIPUS. After 1, 2, 3 and 7 days macrophages and neutrophils were quantified. KEY FINDINGS: With one day, LIPUS led to reductions in the number of neutrophils and M1 macrophages. After two days, muscles treated with LIPUS had fewer total macrophages and M1 macrophages, but a greater number of M2 macrophages. Muscles treated with LIPUS showed fewer macrophages after three and seven days. SIGNIFICANCE: As the permanence of cells with pro-inflammatory and anti-inflammatory action can lead to the perpetuation of inflammation with consequent tissue damage and tissue fibrosis, respectively, the ability of LIPUS to modulate the occurrence of these cells demonstrates the therapeutic potential of this resource.

Cholinergic Stimulation Improves Oxidative Stress and Inflammation in Experimental Myocardial Infarction.

We previously reported that cholinergic stimulation with pyridostigmine (PY) induces anti-inflammatory cell recruitment soon after myocardial infarction (MI). In this study, we evaluated the anti-inflammatory effects of PY during the proliferative phase of cardiac repair by analyzing the infiltration of macrophages, Treg lymphocytes, oxidative stress and inflammatory cytokines. Wistar rats underwent control sham surgery or ligation of the left coronary artery and were randomly allocated to remain untreated (untreated infarcted group, I) or to receive PY (30 mg·kg(-1)·day(-1)) in the supplied water (infarcted treated group, I + PY). Blood pressure and heart rate variability were registered at day 5 post-MI. The animals were euthanized 7 days after thoracotomy, when the hearts were removed and processed for immunohistochemistry (CD68, CD206, FOXP3), cytokines (IL-1ß, IL-6, IL-10, TNF-α) and oxidative stress (superoxide dismutase, catalase, glutathione peroxidase, lipidic and protein peroxidation). PY treatment increased parasympathetic modulation, M2 macrophages and the anti-oxidant enzyme activity but reduced protein oxidation (carbonyls) and the concentration of IL-1ß, IL-6, TNF-α and IL-10. Cholinergic stimulation induces parasympathetic neuro-immune modulation and anti-inflammatory cell enrollment as well as prevents oxidative stress and cytokine production after MI.

Experimental burns: Comparison between silver sulfadiazine and photobiomodulation.

OBJECTIVE: To analyze morphological characteristics and organization of the collagen fibers of third degree burns from scalding compared to laser therapy and silver sulfadiazine, the latter considered as the gold standard. METHOD: Were selected 12 animals (Rattus norvegicus) also divided into three groups (control group [CG] - untreated burns; sulfadiazine group [SG] - burns were treated with silver sulfadiazine at 1%; laser group [LG] - burns were treated with photobiomodulation). The scald burns were carried out by using PVC mold, and the material collected on the 14th day after burn was prepared for morphological and optical retardation analysis for evaluation of inflammatory infiltrates and collagen organization, respectively. RESULTS: On the 14th day, the laser and sulfadiazine groups had mild inflammatory response, while the control group showed an intense inflammatory process, with statistical significance between laser and control groups, but not between sulfadiazine and control groups. Laser and sulfadiazine groups no longer had granulation tissue, opposite to what was seen in the control group. The presence of hair follicles and ulcer did not significantly differ between groups. The optical retardation of collagen fibers was higher in sulfadiazine group, followed by laser and control groups. As for systemic effect, we were able to identify it by simply analyzing the presence or absence of granulation tissue. CONCLUSION: Morphologically, the laser or silver sulfadiazine treatments were similar and both provided better organization of collagen fibers in relation to the untreated group. However, the sulfadiazine group modulated the deposition of collagen fibers more efficiently than the laser group.

Experimental burns: Comparison between silver sulfadiazine and photobiomodulation / Queimadura experimental: comparativo entre sulfadiazina de prata e fotobiomodulação

Summary Objective: To analyze morphological characteristics and organization of the collagen fibers of third degree burns from scalding compared to laser therapy and silver sulfadiazine, the latter considered as the gold standard. Method: Were selected 12 animals (Rattus norvegicus) also divided into three groups (control group [CG] - untreated burns; sulfadiazine group [SG] - burns were treated with silver sulfadiazine at 1%; laser group [LG] - burns were treated with photobiomodulation). The scald burns were carried out by using PVC mold, and the material collected on the 14th day after burn was prepared for morphological and optical retardation analysis for evaluation of inflammatory infiltrates and collagen organization, respectively. Results: On the 14th day, the laser and sulfadiazine groups had mild inflammatory response, while the control group showed an intense inflammatory process, with statistical significance between laser and control groups, but not between sulfadiazine and control groups. Laser and sulfadiazine groups no longer had granulation tissue, opposite to what was seen in the control group. The presence of hair follicles and ulcer did not significantly differ between groups. The optical retardation of collagen fibers was higher in sulfadiazine group, followed by laser and control groups. As for systemic effect, we were able to identify it by simply analyzing the presence or absence of granulation tissue. Conclusion: Morphologically, the laser or silver sulfadiazine treatments were similar and both provided better organization of collagen fibers in relation to the untreated group. However, the sulfadiazine group modulated the deposition of collagen fibers more efficiently than the laser group.

Resumo Objetivo: Analisar características morfológicas e organização das fibras colágenas de queimaduras de terceiro grau provocadas por escaldo em relação à terapia com laser e àquela considerada padrão-ouro, a sulfadiazina de prata. Método: Foram selecionados 12 animais (Rattus norvegicus), divididos igualmente em três grupos (grupo controle [GC] - queimaduras não tratadas; grupo sulfadiazina [GS] - queimaduras tratadas com sulfadiazina de prata 1%; grupo laser [GL] - queimaduras tratadas com fotobiomodulação). As queimaduras foram realizadas por escaldo com a utilização de molde de PVC, e o material coletado no 14º dia pós-queimadura foi preparado para análise morfológica e de retardo óptico, para avaliação do infiltrado inflamatório e da organização do colágeno, respectivamente. Resultados: No 14º dia, os grupos laser e sulfadiazina apresentaram resposta inflamatória leve, enquanto o grupo controle apresentou processo inflamatório intenso, havendo significância estatística entre os grupos laser e controle, mas não entre os grupos sulfadiazina e controle. Enquanto os grupos laser e sulfadiazina não apresentavam mais tecido de granulação, o grupo controle ainda apresentava. A presença de folículo piloso e de úlcera não diferiu significantemente entre os grupos. O retardo óptico das fibras colágenas foi maior no grupo sulfadiazina, seguido dos grupos laser e controle. Apenas a análise da presença ou ausência de tecido de granulação permitiu identificar o efeito sistêmico. Conclusão: Morfologicamente, os tratamentos com laser ou sulfadiazina de prata foram similares e ambos proporcionaram maior organização das fibras colágenas em relação ao grupo não tratado. Entretanto, o grupo sulfadiazina modulou a deposição das fibras colágenas mais eficientemente que o grupo laser.

Increase in cholinergic modulation with pyridostigmine induces anti-inflammatory cell recruitment soon after acute myocardial infarction in rats.

We tested the hypothesis that an increase in the anti-inflammatory cholinergic pathway, when induced by pyridostigmine (PY), may modulate subtypes of lymphocytes (CD4+, CD8+, FOXP3+) and macrophages (M1/M2) soon after myocardial infarction (MI) in rats. Wistar rats, randomly allocated to receive PY (40 mg·kg(-1)·day(-1)) in drinking water or to stay without treatment, were followed for 4 days and then were subjected to ligation of the left coronary artery. The groups-denominated as the pyridostigmine-treated infarcted (IP) and infarcted control (I) groups-were submitted to euthanasia 3 days after MI; the heart was removed for immunohistochemistry, and the peripheral blood and spleen were collected for flow cytometry analysis. Noninfarcted and untreated rats were used as controls (C Group). Echocardiographic measurements were registered on the second day after MI, and heart rate variability was measured on the third day after MI. The infarcted groups had similar MI areas, degrees of systolic dysfunction, blood pressures, and heart rates. Compared with the I Group, the IP Group showed a significant higher parasympathetic modulation and a lower sympathetic modulation, which were associated with a small, but significant, increase in diastolic function. The IP Group showed a significant increase in M2 macrophages and FOXP3(+)cells in the infarcted and peri-infarcted areas, a significantly higher frequency of circulating Treg cells (CD4(+)CD25(+)FOXP3(+)), and a less extreme decrease in conventional T cells (CD25(+)FOXP3(-)) compared with the I Group. Therefore, increasing cholinergic modulation with PY induces greater anti-inflammatory cell recruitment soon after MY in rats.

Effect of laser therapy on immune cells infiltrate after excisional wounds in diabetic rats.

BACKGROUND AND OBJECTIVE: Diabetes alters innate and specific immunity, causing an imbalanced tissue repair process. Very active neutrophils and macrophages are found for a long time in chronic wounds in those individuals. The aim of this study was to evaluate the response of the main effector cells of immunity (neutrophils, macrophages, and T lymphocytes) and to compare the effects of two laser therapy regimens in the postoperative treatment of excision wounds. METHOD: Diabetes was induced in female Wistar rats and a punch was used to cause wounds in the dorsum of each individual. The animals were randomly allocated to a control group (CG), in which the wound was untreated, a single-dose laser group (SLG), in which the wound was submitted to single dose of laser therapy at wavelength of 660 nm, output power of 30 mW, energy density of 4 J/cm(2), and 26-second exposure time, and a fractionated-dose laser group (FLG), submitted to 1 J/cm(2) of laser therapy on Days 1, 3, 8, and 10. Euthanasia was performed on five animals from each group Days 1, 3, 8, 10, 15, and 22. The wound was removed and routinely processed for immunohistochemistry against elastase, CD3, CD68, and CD206 antibodies. The samples were photographed and labeled cells were counted by a blinded observer. The Kruskal-Wallis test was used for the statistical analysis. RESULTS: Neutrophils were predominant in the SLG on Day 1, whereas these cells were mostly found in the CG on Day 3 (P < 0.05). The T lymphocyte count was similar in all groups in the throughout the experiment. On Day 3, the SLG exhibited a greater number of total macrophages (CD68+) (P < 0.05), whereas the macrophage count was similar among the different groups on the other evaluation days. The CD206 + cell counts revealed that the SLG had more M2 macrophages than the CG on Day 8 (P < 0.05), whereas the FLG exhibited more M2 macrophages than the CG on Day 10 (P < 0.05). CONCLUSION: The present findings demonstrate that laser therapy can alter the composition of inflammatory infiltrate in diabetic wounds, leading to a more balanced response transiting from a rapid neutrophil infiltration through to M2 macrophage polarization, especially with a single application of 4 J/cm(2) in the immediate postoperative period.

1-Methyl-D-tryptophan potentiates TGF-ß-induced epithelial-mesenchymal transition in T24 human bladder cancer cells.

Immune escape and metastasis are the hallmarks of several types of cancer including bladder cancer. One of the mechanisms involved in these processes has been linked to indoleamine 2,3-dioxygenase (IDO). Although IDO is classically recognized for its immunomodulatory property, it has presented nonimmunological effects in some tumors. TGF-ß1 is believed to contribute to carcinoma development by modulating immunossupressive molecules, including IDO. In addition, TGF-ß1 induces the epithelial-mesenchymal transition (EMT), which is a critical step in the tumor invasiveness and metastasis. We investigated the role of MT and IDO modulation in the induction of EMT by TGF-ß1 in T24 human bladder carcinoma cells. When T24 cells were incubated with the IDO inhibitor (MT, 1-methyl-D-tryptophan), with TGF-ß1, and with MT+TGF-ß1, a significant decrease of IDO expression and activity was observed. In addition, downregulation of e-cadherin and upregulation of n-cadherin and EMT transcription factors were induced by the treatments, confirming the induction of EMT. siRNA-mediated knockdown of IDO decreased e-cadherin expression, but had no effect on EMT transcription factors. In the scratch-wound assay, the heightened migration process was intensified when the cells were incubated with MT+TGF-ß1. These effects were associated with a robust inhibition of Akt activation. After inoculation of T24 cells under the kidney capsule of Balb/c nude, the cells were positive for IDO in the center of the cell infiltrate, being negative in the periphery, where EMT is high. In conclusion, inhibition of IDO by TGF-ß1 and MT is associated with EMT in T24 human bladder carcinoma cells. MT has potentiating effect in TGF-ß1-induced EMT, independently of IDO. This nonimmunological effect of MT should be considered if IDO is the target to avoid immune escape in bladder cancer.

The effect of low-level laser therapy (LLLT) applied prior to muscle injury.

AIM: To evaluate the effect of LLLT (780 nm; 10 J/cm2 , 40 mW, 3.2 J) prior to injury on the morphological analysis, collagen deposition, and activity of matrix metalloproteinase-2 (MMP-2). METHODS: Wistar rats were divided into groups: control; sham; only LLLT; only muscle injury and LLLT + injury. The rats were euthanized at 1, 3, and 7 days following cryoinjury to muscle that was removed for analysis. RESULTS: LLLT applied prior to muscle injury led to a reduction in myonecrosis and inflammatory cells, an increase of blood vessels and immature muscle fibers. An increase in MMP-2 activity and a decrease in collagen deposition were also found, with a better collagen organization and distribution. CONCLUSION: LLLT applied immediately prior to injury had positive effects during the muscle regeneration process. Therefore, this resource may have considerable therapeutic value, especially for athletes who practice sports in which there is a constant risk of muscle injury. Lasers Surg. Med. 47:571-578, 2015. © 2015 Wiley Periodicals, Inc.

Antimicrobial photodynamic therapy combined with periodontal treatment for metabolic control in patients with type 2 diabetes mellitus: study protocol for a randomized controlled trial.

BACKGROUND: The relationship between diabetes mellitus (DM) and periodontal disease is bidirectional. DM is a predisposing and modifying factor of periodontitis, which, in turn, worsens glycemic control and increases proteins found in the acute phase of inflammation, such as C-reactive protein. The gold standard for the treatment of periodontal disease is oral hygiene orientation, scaling and planing. Moreover, systemic antibiotic therapy may be employed in some cases. In an effort to minimize the prescription of antibiotics, photodynamic therapy (PDT) has been studied as an antimicrobial technique and has demonstrated promising results. The aim of the proposed study is to determine whether PDT as a complement to periodontal therapy (PT) is helpful in the metabolic control of individuals with type 2 diabetes and the reduction of acute-phase inflammatory markers. METHODS/DESIGN: The patients will be randomized using a proper software program into two groups: 1) PT + placebo PDT or 2) PT + active PDT. All patients will first be examined by a specialist, followed by PT performed by two other healthcare professionals. At the end of each session, PDT (active or placebo) will be administered by a fourth healthcare professional. The following will be the PDT parameters: diode laser (660 nm); power output = 110 mW; exposure time = 90 s per point (9 J/point); and energy density = 22 J/cm(2). The photosensitizer will be methylene blue (50 µg/mL). The patients will be re-evaluated 15, 30, 90 and 180 days after treatment. Serological examinations with complete blood count, fasting glucose, glycated hemoglobin and salivary examinations to screen for tumor necrosis factor alpha, interleukin 1, interleukin 6, ostelocalcin, and osteoprotegerin/RANKL will be performed at each evaluation. The data will be statistically evaluated using the most appropriate tests. DISCUSSION: The results of this study will determine the efficacy of photodynamic therapy as an adjuvant to periodontal treatment in diabetic patients. TRIAL REGISTRATION: The protocol for this trial was registered with Clinical Trials registration number NCT01964833 on 14 October 2013.

Tissue responses to postoperative laser therapy in diabetic rats submitted to excisional wounds.

In a previous study about low-level laser therapy biomodulation on a full-thickness burn model we showed that single and fractionated dose regimens increased wound healing and leukocyte influx similarly when compared with untreated control. In order to verify if this finding would be similar in an impaired wound model, we investigated the effect of single and multiple irradiations on wound closure rate, type of inflammatory infiltrate, myofibroblasts, collagen deposition, and optical retardation of collagen in diabetic rats. Female Wistar rats in the same estrous cycle had diabetes induced with streptozotocin and an 8-mm excisional wound performed with a punch. The experimental groups were: control group--untreated ulcer; single-dose group--ulcer submitted to single dose of diode laser therapy (λ = 660 ± 2 nm; P = 30 mW; energy density: 4 J/cm2) and fractionated-dose group--ulcer submitted to 1 J/cm2 laser therapy on Days 1, 3, 8, and 10. The ulcers were photographed on the experimental days and after euthanasia tissue samples were routinely processed for histological and immunohistochemistry analyses. Independently of the energy density, laser therapy accelerated wound closure by approximately 40% in the first three days in comparison to the control group. Laser therapy increased acute inflammatory infiltrate until Day 3. Both laser groups exhibited more myofibroblasts and better collagen organization than the control group. The findings demonstrate that low-level laser therapy in the immediate postoperative period can enhance the tissue repair process in a diabetes model. Similar effects were achieved with laser therapy applied a single time with an energy density of 4 J/cm2 and applied four times with an energy density of 1 J/cm2. The application of laser therapy in the inflammatory phase was the most important factor to the enhancement of the tissue repair process.

Use of low-power laser to assist the healing of traumatic wounds in rats.

PURPOSE: To investigate the morphological aspects of the healing of traumatic wounds in rats using low-power laser. METHODS: Twenty four non isogenic, young adult male Wistar rats (Rattus norvegicus) weighing between 200 and 300 g was used. The animals were randomly distributed into two groups: Control (GC) and Laser (GL), with 12 animals each. After shaving, anesthesia was performed in the dorsal region and then a surgical procedure using a scalpel was carried out to make the traumatic wound. GL received five sessions of laser therapy in consecutive days using the following laser parameters: wavelength 660 nm, power 100 mW, dose 10 J/cm2. The wounds were evaluated through measurement of the area and depth of the wound (MW) and histological analysis (HA). RESULTS: When comparing the GC with the GL in MW there was a difference in area (p<0.001) and depth (p=0.003) measurement of the wounds in GL. The laser group presented more epithelization than GC (p=0.03). The other histological parameters were similar. CONCLUSION: The healing of wounds in rats was improved with the use of the laser.

Use of low-power laser to assist the healing of traumatic wounds in rats

PURPOSE: To investigate the morphological aspects of the healing of traumatic wounds in rats using low-power laser. METHODS: Twenty four non isogenic, young adult male Wistar rats (Rattus norvegicus) weighing between 200 and 300g was used. The animals were randomly distributed into two groups: Control (GC) and Laser (GL), with 12 animals each. After shaving, anesthesia was performed in the dorsal region and then a surgical procedure using a scapel was carried out to make the traumatic wound. GL received five sessions of laser therapy in consecutive days using the following laser parameters: wavelength 660 nm, power 100 mW, dose 10 J/cm2. The wounds were evaluated through measurement of the area and depth of the wound (MW) and histological analysis (HA). RESULTS: When comparing the GC with the GL in MW there was a difference in area (p<0.001) and depth (p=0.003) measurement of the wounds in GL. The laser group presented more epithelization than GC (p=0.03). The other histological parameters were similar. CONCLUSION: The healing of wounds in rats was improved with the use of the laser. .

Photodynamic therapy as a novel treatment for halitosis in adolescents: study protocol for a randomized controlled trial.

BACKGROUND: Halitosis is a common problem that affects a large portion of the population worldwide. The origin of this condition is oral in 90% and systemic in 10% of cases. The unpleasant odor is mainly the result of volatile sulfur compounds produced by Gram-negative bacteria. However, it has recently been found that anaerobic Gram-positive bacteria also produce hydrogen sulfide (H2S) in the presence of amino acids, such as cysteine. Light, both with and without the use of chemical agents, has been used to induce therapeutic and antimicrobial effects. In photodynamic therapy, the antimicrobial effect is confined to areas covered by photosensitizing dye. The aim of the present study is to evaluate the antimicrobial effect of photodynamic therapy on halitosis in adolescents through the analysis of volatile sulfur compounds measured using gas chromatography and microbiological analysis of coated tongue. METHODS/DESIGN: A quantitative clinical trial will be carried out involving 60 adolescents randomly divided into the following groups: group 1 will receive treatment with a tongue scraper, group 2 will receive photodynamic therapy applied to the posterior two-thirds of the dorsum of the tongue, and group 3 will receive combined treatment (tongue scraper and photodynamic therapy). Gas chromatography (OralChromaTM) and microbiological analysis will be used for the diagnosis of halitosis at the beginning of the study. Post-treatment evaluations will be conducted at one hour and 24 hours after treatment. The statistical analysis will include the Shapiro-Wilk test for the determination of the distribution of the data. If normal distribution is demonstrated, analysis of variance followed by Tukey's test will be used to compare groups. The Kruskal-Wallis test followed by the Student-Newman-Keuls test will be used for data with non-normal distribution. Either the paired t-test or the Wilcoxon test will be used to compare data before and after treatment, depending on the distribution of the data. DISCUSSION: The results of this trial will determine the efficacy of using photodynamic therapy alone or in combination with a tongue scraper to treat bad breath in adolescents. TRIAL REGISTRATION: The protocol for this study was registered with Clinical Trials (registration number NCT02007993) on 10 December 2013.

Facial reconstruction surgery 10 years after treatment for hemangiopericytoma: planning considerations and clinical outcomes.

This paper describes the surgical correction of ankylosis of the right temporomandibular joint and reconstruction of the middle and lower thirds of the right side of the face in a young man who had undergone treatment for hemangiopericytoma 10 years earlier, which led to serious functional, esthetic, and psychological problems and diminished his quality of life. The results of reconstruction surgery with alloplastic material (Medopor®) and surgical planning with fibrotic tissue due to radiation and the risk of osteoradionecrosis are discussed.

Photodynamic therapy as novel treatment for halitosis in adolescents: a case series study.

INTRODUCTION: Halitosis is a common problem that affects a large portion of the population worldwide. The origin of this condition is oral in 90% of cases and systemic in 10% of cases. The foul odor is caused mainly by volatile sulfur compounds produced by Gram-negative bacteria. However, it has recently been found that anaerobic Gram-positive bacteria also produce hydrogen sulfide (H2S) in the presence of amino acids, such as cysteine. Light with and without the combination of chemical agents has been used to induce therapeutic and antimicrobial effects. In photodynamic therapy, the antimicrobial effect is confined to areas covered by the photosensitizing dye. The aim of the present case series study was to evaluate the antimicrobial effect of photodynamic therapy on halitosis in adolescents through the analysis of volatile sulfur compounds measured using a sulfide meter (Halimeter®). METHODS: Five adolescents aged 14 to 16 years were evaluated using a sulfide meter before and one hour after photodynamic therapy, which involved the use of methylene blue 0.005% on the middle third and posterior thirds of the dorsum of the tongue and nine points of laser irradiation in the red band (660 nm) with an energy dose of 9 J, power output of 100 mW and 90-seconds exposure time. RESULTS: A 31.8% reduction in the concentration of volatile sulfur compounds was found in the comparison of the initial and final readings. The statistically significant reduction (p = 0.0091) led to an absence of halitosis following treatment (mean: 58.2 ppb). CONCLUSION: Photodynamic therapy seems to be effective on reduction the concentration of volatile sulfur compounds.Considering the positive effects of photodynamic therapy in this case series, further studies involving microbiological analyses should be conducted to allow comparisons of the results.