Osteoradionecrosis in a Torus Mandibularis Treated by Antimicrobial Photodynamic Therapy: A Case Report.

Background: Osteoradionecrosis (ORN) of the jaws is a late complication after radiotherapy to head and neck cancer. Objective: To describe a rare case of ORN of the torus mandibularis that was successfully managed exclusively with antimicrobial photodynamic therapy (aPDT). Case report: A 72-year-old man presented an exposed necrotic bone observed in the torus mandibularis, extending to the lingual alveolar ridge with no edema nor suppuration. The treatment provided a noninvasive treatment leading to spontaneous sequestrectomy of the torus in 2 weeks with complete mucosal repair in 5 weeks and absence of lesion signs and/or symptoms even after 6 months of follow-up. Conclusions: The aPDT indicated to be a satisfactory treatment for ORN affecting torus mandibularis, a region with surgical limitations, avoiding surgery.

Efficacy of photobiomodulation therapy on healing of ionizing irradiated bone: a systematic review of in vivo animal studies.

This systematic review aimed to answer the research focused question: What are the effects of photobiomodulation (PBM) therapy on bone healing after ionizing irradiation in animal models? The EMBASE, LILACS, LIVIVO, PubMed, Scopus, and Web of Science databases, including gray literature, were searched using the following keywords: "Head and Neck Neoplasms"; "Ionizing Radiation"; "Low-Level Light Therapy"; and "Bone regeneration", focusing on the primary studies that assessed the effects of PBM therapy on animal models of irradiated bone. Six studies have met the eligibility criteria and presented an overall regular quality according to the risk of bias assessment tools. All the studies utilized rat animal model and near-infrared laser PBM at low power output setting. Most of the studies showed increased new bone formation, osteocytes, osteoblasts, and vascularization networking, as a result of PBM therapy. However, only one out of the six studies has not shown any differences in bone healing in both lased and non-lased animal groups. Nevertheless, PBM therapy is a potential tool to improve bone healing induced by ionizing radiation. However, due to the scarce number of studies and the great variability of laser parameters and treatment protocols, a clear conclusion cannot be drawn. Hence, extensive preclinical in vivo studies are warranted to ensure these beneficial effects have been addressed prior to translational clinical trials.

Responses of melanoma cells to photobiomodulation depend on cell pigmentation and light parameters.

Melanoma is a highly aggressive skin cancer that requires new approaches for its management. Low-level laser therapy, currently named photobiomodulation therapy (PBM), has been used to improve different conditions but its effects and safe use on melanoma remain unexplored. Herein, we investigated the PBM impact on melanoma cells differing by pigmentation using near-infrared (NIR) and red lasers in vitro. In vivo, we evaluated the effects of the red laser on melanoma-bearing mice. Amelanotic (SK-MEL-37) and melanotic (B16F10) cells were exposed in vitro to a NIR (780 nm, 40 mW) or a red laser (660 nm, 40 mW) in 3 different light doses: 30, 90, and 150 J/cm2 and responses were assessed regarding mitochondrial activity, invasiveness, migration, and VEGF production. In vivo, melanoma-bearing mice received the red laser delivering 150 J/cm2 directly to the tumor on 3 consecutive days. Mice were monitored for 15 days regarding tumor progression and mouse survival. We noticed that amelanotic cells were unresponsive to NIR light. In contrast, NIR irradiation at 30 J/cm2 promoted an increase in the invasiveness of pigmented cells, even though all light doses have inhibited cell migration. Regarding the red laser on pigmented cells, the highest light dose (150 J/cm2) decreased the VEGF production and migration. In vivo, melanoma-bearing mice treated with red laser showed smaller tumor volume and longer survival than controls. We conclude that PBM appears to be safe for amelanotic non-pigmented melanoma but triggers different responses in melanotic pigmented cells depending on light parameters. Additionally, a high dose of red laser impairs the invasive behavior of melanoma cells, probably due to the decrease in VEGF synthesis, which may have contributed to tumor arrest and increased mouse survival. These findings suggest that red laser therapy could be a new ally in the supportive care of melanoma patients.

Violet led dental whitening: Effectiveness and biological safety: An in vitro study.

INTRODUCTION: The light-emitting diode (Led) in the violet spectrum associated or not with hydrogen peroxide (HP) has been suggested as a promising technique for dental bleaching. Violet led has a wavelength of 405-410 nm, which is very close to that of ultraviolet (UV) radiation, and this has raised biological safety concerns. AIM: To investigate the effectiveness of the violet led dental bleaching technique by evaluating color parameters, enamel surface microhardness, and biological safety analysis. METHODS: One hundred bovine dental blocks were divided into groups according to the bleaching technique (G1 - only HP; G2 - HP associated with blue led; G3 - only blue led; G4 - HP associated with a violet led; and G5 - only violet led). The color analysis (ΔE, ΔL, and WID) and enamel surface microhardness were assessed before and after bleaching (immediately, 5, 14, and 30 days). The biological safety of the violet led irradiation was assessed by measuring the number of micronuclei formed in human cells in culture in response to irradiation. Data analysis included Kruskal-Wallis test, Friedman test, and Mann-Whitney test. RESULTS: In groups G4 and G5 there was the formation of precipitates on the enamel surface. At the time of 14 days, it was observed that the G2 group had lower values of microhardness than G5. ΔL and ΔE showed differences between groups in experimental times. Mean percentages of micronuclei occurrence were similar in the control group and the violet led group. CONCLUSION: The violet led irradiation can be applied for dental bleaching because this approach produces significant color changes preserving tooth enamel integrity and causes no genotoxic effects on vital cells.

Photobiomodulation treatments drive osteogenic versus adipocytic fate of bone marrow mesenchymal stem cells reversing the effects of hyperglycemia in diabetes.

Diabetes mellitus (DM) is a chronic metabolic disease that affects bone metabolism, which can be related to a reduced osteogenic potential of bone marrow mesenchymal stem cells (BM-MSCs). MSCs from diabetic rats (dBM-MSC) have shown a tendency to differentiate towards adipocytes (AD) instead of osteoblasts (OB). Since photobiomodulation (PBM) therapy is a non-invasive treatment capable of recovering the osteogenic potential of dBM-MSCs, we aimed to evaluate whether PBM can modulate MSC's differentiation under hyperglycemic conditions. BM-MSCs of healthy and diabetic rats were isolated and differentiated into osteoblasts (OB and dOB) and adipocytes (AD and dAD). dOB and dAD were treated with PBM every 3 days (660 nm; 5 J/cm2; 0.14 J; 20 mW; 0.714 W/cm2) for 17 days. Cell morphology and viability were evaluated, and cell differentiation was confirmed by gene expression (RT-PCR) of bone (Runx2, Alp, and Opn) and adipocyte markers (Pparγ, C/Ebpα, and C/Ebpß), production of extracellular mineralized matrix (Alizarin Red), and lipid accumulation (Oil Red). Despite no differences on cell morphology, the effect of DM on cells was confirmed by a decreased gene expression of bone markers and matrix production of dOB, and an increased expression of adipocyte and lipid accumulation of dAD, compared to heatlhy cells. On the other hand, PBM reversed the effects of dOB and dAD. The negative effect of DM on cells was confirmed, and PBM improved OB differentiation while decreasing AD differentiation, driving the fate of dBM-MSCs. These results may contribute to optimizing bone regeneration in diabetic patients.

Autologous platelet concentrates in extraction sockets for the prevention of osteoradionecrosis: a systematic review of controlled clinical trials.

This systematic review aimed to assess whether the use of autologous platelet concentrates immediately after tooth extraction would prevent ORN in patients treated with radiotherapy (RT) for head and neck cancer (HNC). MEDLINE, Embase, Ovid, Scopus, Web of Science, CENTRAL Cochrane, and OpenGrey databases were searched (up to, and including, June 2021) by two independent reviewers to identify studies, followed by further manual search. As inclusion and exclusion criteria for the studies, only controlled clinical trials (randomized or not) were considered. The risk of bias of each included study was assessed using the Cochrane Risk of Bias Tool. Of the 129 potentially eligible studies, only 2 were included, both randomized controlled clinical trials; however, one used platelet-rich plasma and another leukocyte- and platelet-rich fibrin. Overall, both autologous platelet concentrates had no effect on the outcome assessed. The use of autologous platelet concentrates seems not to be beneficial for ORN prevention following tooth extractions in HNC patients treated with RT; however, according to the available evidence, a reliable statement cannot be made.

Dental tissue-derived stem cell sheet biotechnology for periodontal tissue regeneration: A systematic review.

OBJECTIVE: This study aimed to conduct a systematic review of the use of a cell sheet formed by mesenchymal stem cells derived from dental tissues (ddMSCs) for periodontal tissue regeneration in animal models in comparison with any other type of regenerative treatment. DESIGN: PubMed and Scopus databases were searched for relevant studies up to December 2020. The review was conducted based on the Preferred Reporting Items for Systematic Reviews and Meta-analysis guidelines. RESULTS: Of the 1542 potentially relevant articles initially identified, 33 fulfilled the eligibility criteria and were considered for this review. Even with a wide variety of selected study methods, the periodontal tissue was always regenerated; this indicates the potential for the use of these cell sheets in the future of periodontics. However, this regeneration process is not always complete. CONCLUSION: Despite the implantation, ddMSCs sheets have a great potential to be used in the regeneration of periodontal tissue. More in vivo studies should be conducted using standardized techniques for cell sheet implantation to obtain more robust evidence of the relevance of using this modality of cell therapy for periodontal tissue regeneration.

Recovering the osteoblastic differentiation potential of mesenchymal stem cells derived from diabetic rats by photobiomodulation therapy.

Autologous cell-based therapy for bone regeneration might be impaired by diabetes mellitus (DM) due to the negative effects on mesenchymal stem cells (MSCs) differentiation. Strategies to recover their osteogenic potential could optimize the results. We aimed to evaluate the effect of photobiomodulation (PBM) therapy on osteoblast differentiation of rats with induced DM. Bone marrow MSCs of healthy and diabetic rats were isolated and differentiated into osteoblasts (OB and dOB, respectively). dOB were treated with PBM therapy every 72 hour (660 nm; 0.14 J; 20 mW; 0.714 W/cm2 , and 5 J/cm2 ). Cell morphology, viability, gene and protein expression of osteoblastic markers, alkaline phosphatase (ALP) activity, and the mineralized matrix production of dOB-PBM were compared to dOB. PBM therapy improved viability of dOB, increased the gene and protein expression of bone markers, the ALP activity and the mineralized matrix production. PBM therapy represents an innovative therapeutic approach to optimize the treatment of bone defects in diabetic patients.

Claudin expression is maintained in mucoepidermoid carcinoma of the salivary gland.

OBJECTIVE: The aim of the present study was to investigate the expression of claudin-1, -3, -4, -5 and -7 proteins in mucoepidermoid carcinoma of oral cavity and analyze whether EGF may interfere in the expression of the genes that encode claudins using in vitro models. MATERIAL AND METHODS: Using immunohistochemistry, the expression of claudins was searched in 36 histologically graded cases of mucoepidermoid carcinoma. The association of expression of claudins with clinical-pathological parameters was evaluated. An in vitro step investigated the influence of EGF on gene expression of claudins by real time RT-PCR technique. RESULTS: Claudin-1, -3, -4, -5, and -7 were highly expressed in most mucoepidermoid carcinomas. These expressions were compared with clinicopathological parameters. High expression of claudin-1 was associated with patients over 40 years-old (p = 0.05) and Caucasians (p = 0.024). In vitro experiments demonstrated a tendency for Claudin gene expression increase after EGF stimulus. CONCLUSIONS: The expression of claudins is maintained in mucoepidermoid carcinoma cells and EGF could be related with this expression. Our results point out to a fundamental biological importance to CLDNs in normal and neoplastic tissue. The expression patterns of CLDNs does not yet allow a clinical application, but the biological knowledge will ground evidence to new studies towards possible target-therapies.

Evaluation of Resin-Based Material Containing Copaiba Oleoresin (Copaifera Reticulata Ducke): Biological Effects on the Human Dental Pulp Stem Cells.

The purpose of this study was to analyze in vitro the biological effects on human dental pulp stem cells triggered in response to substances leached or dissolved from two experimental cements for dental pulp capping. The experimental materials, based on extracts from Copaifera reticulata Ducke (COP), were compared to calcium hydroxide [Ca(OH)2] and mineral trioxide aggregate (MTA), materials commonly used for direct dental pulp capping in restorative dentistry. For this, human dental pulp stem cells were exposed to COP associated or not with Ca(OH)2 or MTA. Cell cytocompatibility, migration, and differentiation (mineralized nodule formation (Alizarin red assay) and gene expression (RT-qPCR) of OCN, DSPP, and HSP-27 (genes regulated in biomineralization events)) were evaluated. The results showed that the association of COP reduced the cytotoxicity of Ca(OH)2. Upregulations of the OCN, DSPP, and HSP-27 genes were observed in response to the association of COP to MTA, and the DSPP and HSP-27 genes were upregulated in the Ca(OH)2 + COP group. In up to 24 h, cell migration was significantly enhanced in the MTA + COP and Ca(OH)2 + COP groups. In conclusion, the combination of COP with the currently used materials for dental pulp capping [Ca(OH)2 and MTA] improved the cell activities related to pulp repair (i.e., cytocompatibility, differentiation, mineralization, and migration) including a protective effect against the cytotoxicity of Ca(OH)2.

Successful application of antimicrobial photodynamic and photobiomodulation therapies for controlling osteoradionecrosis and xerostomia after laryngeal carcinoma treatment: A case report of full oral rehabilitation.

We present a clinical case where a conservative treatment based on photonics [antimicrobial Photodynamic Therapy (aPDT) associated to Photobiomodulation therapy (PBMT)] of a patient with osteoradionecrosis (ORN) due to radiotherapy treatment of a laryngeal cancer. As a result of this combined treatment the ORN was controlled (e.g. the necrosis, infection and suppuration disappeared). Moreover, the symptoms reported by the patient (pain and xerostomia) also diminished along with the repair of oral mucosa. In future cases this combined therapy (e.g. PBM therapy and the aPDT) will be further examined.

Aquaporin 1, 3, and 5 Patterns in Salivary Gland Mucoepidermoid Carcinoma: Expression in Surgical Specimens and an In Vitro Pilot Study.

Salivary gland aquaporins (AQPs) are essential for the control of saliva production and maintenance of glandular structure. However, little is known of their role in salivary gland neoplasia. Salivary gland tumors comprise a heterogeneous group of lesions, featuring variable histological characteristics and diverse clinical behaviors. Mucoepidermoid carcinoma (MEC) is the most common salivary gland malignancy. The aim of this study was to evaluate the expression of AQP1, AQP3, and AQP5 in 24 MEC samples by immunohistochemistry. AQP1 expression was observed in vascular endothelium throughout the tumor stroma. AQP3 was expressed in epidermoid and mucosal cells and AQP5 was expressed in mucosal cells of MEC. These proteins were expressed in the human MEC cell line UH-HMC-3A. Cellular ultrastructural aspects were analyzed by electron microscopy to certificate the tumor cell phenotype. In summary, our results show that, despite the fact that these molecules are important for salivary gland physiology, they may not play a distinct role in tumorigenesis in MEC. Additionally, the in vitro model may offer new possibilities to further investigate mechanisms of these molecules in tumor biology and their real significance in prognosis and possible target therapies.

Photobiomodulation as an adjunctive therapy for alveolar socket preservation: a preliminary study in humans.

Bone remodeling results in loss of alveolar bone height and thickness. Photobiomodulation (PBM) based on photochemical stimulation by low-intensity lasers emerges as an adjunctive therapy for alveolar socket preservation. Our study aimed to evaluate the effects of PBM therapy on alveolar bone repair. Twenty healthy patients in need of bilateral extraction of lower molars were enrolled in this split-mouth randomized and blind clinical trial. The extraction sites were randomly selected to receive either the PBM therapy with a CW GaAIAs diode laser (808 nm; 0.028 mm2; 0.1 W; 3.6 W/cm2; 89 J/cm2; 2.5 J/point) or no treatment (Control). Bone biopsies were harvested 45 days after the dental extraction and evaluated using micro-computerized tomography (µCT), morphometric, and histological analysis. Data were compared using the paired t test, and the level of significance was set at 5%. Bone surface (p = 0.029), bone surface/total volume (p = 0.028), trabecular number (p = 0.025), and connectivity density (p = 0.029) were higher at the PBM group compared with Control. The histological observations confirmed the µCT findings. PBM samples exhibited higher number of organized and connected bone trabeculae along with higher density of blood vessels than Control. Control samples displayed a dense and highly cellular connective tissue at the central area accompanied by the presence of immature bone trabeculae at the periphery. Our results indicated that the PBM therapy improved the newly bone trabeculae formation and their connectivity which increased bone surface, indicating the positive effect of the laser on alveolar human socket repair.

Antimicrobial photodynamic and photobiomodulation adjuvant therapies for prevention and treatment of medication-related osteonecrosis of the jaws: Case series and long-term follow-up.

BACKGROUND: Medication-Related Osteonecrosis of the Jaws (MRONJ) incidence are increasing among elderly. Treatment can be challenging. Prevent or treatment protocols that control evolution of the lesion are warranted. OBJECTIVE: To observe long-term outcomes of two protocols based on photonics [antimicrobial photodynamic therapy (aPDT) and photobiomodulation (PBM)] for prevention and treatment of MRONJ lesions. METHODS: In a prospective study, patients who needed oral surgery and had been exposed to antiresorptive drugs were long-term followed-up. For MRONJ prevention, immediately after tooth extraction aPDT was applied. For aPDT a 0.01 % methylene blue solution was applied inside socket for 5 min followed by irradiation with a diode laser [660 nm, 0.028cm2, 0.1 W, 3.57 W/cm2, 90 s and 9 J per point, 321 J/cm2, at least at in 3 points (laser probe was placed at central, and two equidistant points) and total energy of 27J]. Irradiation was repeated weekly until total tissue repair. MRONJ treatment included preoperative aPDT sessions until signs and symptoms of infection had reduced. Then, after necrotic bone removal, aPDT was applied inside surgical wounds and re-applied weekly until healing. Antibiotics were administered pre or postoperatively for no longer than 7 days. PBM therapy was applied with 808 nm diode laser, 0.028cm2, 0.1 W, 3.57 W/cm2, 30 s, 107 J/cm², 3 J and total energy of 12 J until evidence of remission. RESULTS: Eighteen patients underwent preventive protocol, and none presented signs of MRONJ after a follow-up of at least 6 months. Seventeen patients presented with MRONJ underwent aPDT protocol and sixteen of them showed total regression of lesions. PRACTICAL IMPLICATIONS: aPDT and PBM therapy protocols appear to be effective as adjuvant approach not only for preventing MRONJ development due to tooth extraction but for treating MRONJ lesions at early stages with no adverse effects.

Examining tumor modulating effects of photobiomodulation therapy on head and neck squamous cell carcinomas.

Photobiomodulation (PBM) therapy is an effective method for preventing and managing oral mucositis (OM) in head and neck squamous cell carcinoma (HNSCC) patients undergoing radiotherapy alone or in combination with chemotherapy. However, the potential effects of PBM therapy on premalignant and malignant cells eventually present in the treatment site are yet unknown. The aim of this systematic review was to analyze the effects of PBM therapy on HNSCC. A literature search was conducted in four indexed databases as follows: MEDLINE/PubMed, EMBASE, Web of Science, and Scopus. The databases were reviewed for papers published up to and including in October 2018. In vitro and in vivo studies that investigated the effects of PBM therapy on HNSCC were selected. From the 852 initially gathered studies, 15 met the inclusion criteria (13 in vitro and 2 in vivo). Only three in vitro studies were noted to have a low risk of bias. The included data demonstrated wide variations of study designs, PBM therapy protocols, and study outcomes. Cell proliferation and viability were the primary evaluation outcome in the in vitro studies. Of the 13 in vitro studies, seven noted a positive effect of PBM therapy on inhibiting or preventing an effect on HNSCC tumor cells, while six studies saw increased proliferation. One in vivo study reported increased oral SCC (OSCC) progression, while the other observed reduced tumor progression. Overall, the data from the studies included in the present systematic review do not support a clear conclusion about the effects of PBM therapy on HNSCC cells.

Hemolasertherapy: A Novel Procedure for Gingival Papilla Regeneration-Case Report.

BACKGROUND: Interdental papilla is of major importance to patients' orofacial aesthetics, especially regarding anterior teeth as part of the smile's harmony. Loss of gingival tissue, which constitutes interdental papilla, forms what in odontology is called black spaces. This loss, besides affecting the smile's aesthetics, also provokes phonetic and functional damage. OBJECTIVE: The objective of the authors is to present the result of three clinical cases treated with an innovative technique called hemolasertherapy, which stimulates growth of gingival papilla and thus permanently fills in the black spaces. METHODS: The photobiomodulation therapy (PBMT) used a 660 nm diode laser (Laser Duo, MMO-São Carlos, SP, Brazil), punctual, contact mode in two steps: before the bleeding (first PBMT) and immediately after bleeding (second PBMT). Parameters used were power output: 100 mW, CW; diameter tip: 5 mm; spot area: 0.19 cm2; irradiation exposure time per point: 20 sec; 14 points per daily session; total of 2 sessions, with a 1-week interval; E: 2 J per point; E: per daily session, 28 J; irradiance per point: 0.52 W/cm2; fluence per point: 10.4 J/cm2. Total in two daily sessions: total energy: 56 J; total fluence: 294.75 J/cm, 560 sec total time. An in vitro preliminary study was simultaneously carried out to demonstrate what could happen at cellular level in hemotherapy clinical cases associated with PBMT laser application. RESULTS: This initial study demonstrated that the blood clot originated from the bleeding provoked in the gingival area is rich in mesenchymal stem cells. PBMT enables preservation, viability, and further differentiation, stimulating the return of gingival stem cells, which would support their survival and differentiation in the blood clot, thus favoring interdental papilla regeneration. CONCLUSIONS: Follow-up was done for a time span of 4-5 years and considered excellent with regard to papilla preservation.

Effect of Nd:YAG and CO2 Laser Irradiation on Prevention of Enamel Demineralization in Orthodontics: In Vitro Study.

OBJECTIVE: The aim of this study was to investigate Nd:YAG and CO2 laser effects in the prevention of demineralization in deeper layers of enamel via successive acid challenge cycles. BACKGROUND DATA: Lasers are promising in the prevention of enamel demineralization around the orthodontic brackets; however, there are very few studies that evaluate if the effects of treatment could be extended after successive acid challenge cycles due to permanent enamel structural alterations. MATERIALS AND METHODS: Human enamel samples were divided into five groups (n = 12): G1-application of 1.23% acidulated fluoride phosphate gel (AFP, control); G2-Nd:YAG laser irradiation (0.6 W, 84.9 J/cm2, 10 Hz, 110 µs, contact mode); G3-Nd:YAG laser irradiation associated with AFP; G4-CO2 laser irradiation (0.5 W, 28.6 J/cm2, 50 Hz, 5 µs, and 10 mm focal distance); and G5-CO2 laser irradiation associated with AFP. The samples were submitted to successive acid challenge cycles. Quantitative light-induced fluorescence and scanning electron microscopy were used to assess enamel demineralization. The data were statistically compared (α = 5%). RESULTS: G1: 50.87 ± 4.57; G2: 47.72 ± 2.87; G3: 50.96 ± 4.01; G4: 28.21 ± 2.19; and G5: 30.13 ± 6.38. The CO2 laser groups had significantly lower mineral losses than those observed in all other groups after successive acid challenge cycles. CONCLUSIONS: Only the CO2 laser (10.6 µm) irradiation prevents enamel demineralization around the orthodontic brackets even after exposure to successive acid challenges. The CO2 laser at 10.6 µm showed a deeper effect in enamel regarding caries prevention.

Low-intensity laser phototherapy enhances the proliferation of dental pulp stem cells under nutritional deficiency.

Dental trauma in immature permanent teeth can damage pulp vascularization, which leads to necrosis and cessation of apexogenesis. Studies on tissue engineering using stem cells from human exfoliated deciduous teeth (SHEDs) have yielded promising results. Laser phototherapy (LPT) is able to influence the proliferation and differentiation of these cells, which could improve tissue engineering. SHEDs (eighth passage) were seeded into 96-well culture plates (103 cells/well) and were grown in culture medium supplemented with 15% defined fetal bovine serum (FBS) for 12 h. After determining the appropriate nutrition deficiency status (5% FBS), the cells were assigned into four groups: 1) G1 - 15% FBS (positive control); 2) G2 - 5% FBS (negative control); 3) G3 - 5% FBS+LPT 3 J/cm2; and 4) G4 - 5% FBS+LPT 5 J/cm2. For the LPT groups, two laser irradiations at 6 h intervals were performed using a continuous wave InGaAlP diode laser (660 nm, with a spot size of 0.028 cm2, 10 mW) in punctual and contact mode. Cell viability was assessed via an MTT reduction assay immediately after the second laser irradiation (0 h) and 24, 48, and 72 h later. We found that G3 and G4 presented a significantly higher cell growth rate when compared with G2 (p < 0.01). Moreover, G4 exhibited a similar cell growth rate as G1 throughout the entire experiment (p > 0.05). These findings indicate that LPT with 5 J/cm2 can enhance the growth of SHEDs during situations of nutritional deficiency. Therefore, LPT could be a valuable adjunct treatment in tissue engineering when using stem cells derived from the dental pulp of primary teeth.

Photobiomodulation of Dental Derived Mesenchymal Stem Cells: A Systematic Review.

OBJECTIVE: This study aimed to conduct a systematic review of the literature published from 2000 to August 2015, to investigate the effect of photobiomodulation (PBM) therapy on dentoalveolar-derived mesenchymal stem cells (ddMSCs), assessing whether a clear conclusion can be reached from the data presented. BACKGROUND DATA: Systematic reviews provide the best evidence on the effectiveness of a procedure and permit investigation of factors that may influence the performance of a method. To the best of our knowledge, no previous systematic review has evaluated the effects of PBM only on ddMSCs. METHODS: The search was conducted in PubMed /MEDLINE®, Scopus and Web of Science databases, and reported according to the Preferred Reporting Items for Systematic Reviews and Metaanalyses (PRISMA Statement). Original research articles investigating the effects of PBM therapy on ddMSCs, published from 2000 to August 2015, were retrieved and used for this review according to the following eligibility criteria: evaluating PBM therapy, assessing stem cells of dentoalveolar origin, published in English, dealing with cells characterized as stem cells, and using light that did not need external chromophores. RESULTS: From the initial 3467 potentially relevant articles identified, 6 were excluded because they were duplicates, and 3453 were considered ineligible based on the inclusion criteria. Therefore, eight articles remained, and these were fully analyzed in order to closely check exclusion criteria items. Only one of them was excluded because the cultured cells studied were not characterized as stem cells. Finally, seven articles served as the basis for this systematic review. CONCLUSIONS: PBM therapy has no deleterious effects on ddMSCs. Although no other clear conclusion was obtained because of the scarce number of publications, the results of these studies are pointing to an important tendency of PBM therapy to improve ddMSCs' viability and proliferation.

Low-intensity laser phototherapy enhances the proliferation of dental pulp stem cells under nutritional deficiency

Abstract Dental trauma in immature permanent teeth can damage pulp vascularization, which leads to necrosis and cessation of apexogenesis. Studies on tissue engineering using stem cells from human exfoliated deciduous teeth (SHEDs) have yielded promising results. Laser phototherapy (LPT) is able to influence the proliferation and differentiation of these cells, which could improve tissue engineering. SHEDs (eighth passage) were seeded into 96-well culture plates (103 cells/well) and were grown in culture medium supplemented with 15% defined fetal bovine serum (FBS) for 12 h. After determining the appropriate nutrition deficiency status (5% FBS), the cells were assigned into four groups: 1) G1 - 15% FBS (positive control); 2) G2 - 5% FBS (negative control); 3) G3 - 5% FBS+LPT 3 J/cm2; and 4) G4 - 5% FBS+LPT 5 J/cm2. For the LPT groups, two laser irradiations at 6 h intervals were performed using a continuous wave InGaAlP diode laser (660 nm, with a spot size of 0.028 cm2, 10 mW) in punctual and contact mode. Cell viability was assessed via an MTT reduction assay immediately after the second laser irradiation (0 h) and 24, 48, and 72 h later. We found that G3 and G4 presented a significantly higher cell growth rate when compared with G2 (p < 0.01). Moreover, G4 exhibited a similar cell growth rate as G1 throughout the entire experiment (p > 0.05). These findings indicate that LPT with 5 J/cm2 can enhance the growth of SHEDs during situations of nutritional deficiency. Therefore, LPT could be a valuable adjunct treatment in tissue engineering when using stem cells derived from the dental pulp of primary teeth.