Gingival neoplasms: a multicenter collaborative study of 888 patients in Brazil

Background: To evaluate the prevalence and clinicopathological features of a large series of gingival neoplasms in Brazil. Material and methods: All gingival benign and malignant neoplasms were retrieved from the records of six Oral Pathology Services in Brazil, during a 41-year period. Clinical and demographic data, clinical diagnosis, and histopathological data were collected from the patients' clinical charts. For statistical analysis, the chi-square, median test of independent samples and the U Mann-Whitney tests were used, considering a significance of 5%. Results: From 100,026 oral lesions, 888 (0.9%) were gingival neoplasms. There were 496 (55.9%) males, with a mean age of 54.2 years. Most cases (70.3%) were malignant neoplasms. Nodules (46.2%) and ulcers (38.9%) were the most common clinical appearance for benign and malignant neoplasms, respectively. Squamous cell carcinoma (55.6%) was the most common gingival neoplasm, followed by squamous cell papilloma (19.6%). In 69 (11.1%) malignant neoplasms, the lesions were clinically considered to be inflammatory or of infectious origin. Malignant neoplasms were more common in older men, appeared with larger size, and with a time of complaint shorter than benign neoplasms (p<0.001). Conclusions: Benign and malignant tumors may appear as nodules in gingival tissue. In addition, malignant neoplasms, especially squamous cell carcinoma, should be considered in the differential diagnosis of persistent single gingival ulcers. (AU)

Calcifying odontogenic cyst with AOT-like features: a case report and literature review / Cisto odontogênico calcificante com características adenomatóides: relato de caso e revisão de literatura

Odontogenic lesions are a heterogeneous group of diseases that presents differences in their biological behavior and the occurrence of variable inductive interactions. Calcifying odontogenic cyst (COC), or Gorlin's cyst, is a well-recognized example of these lesions. We describe a case of COC with AOT-like areas and highlights its morphological diversity. A 60-year-old pheoderma man presented with a large swelling in the anterior buccal region of the mandible. Panoramic radiography revealed a well-defined, unilocular, radiolucent lesion associated with important root resorption. Complete enucleation of the lesion was performed and the histopathological findings met the criteria for the diagnosis of COC, although the cyst exhibited unusual AOT-like features. The patient has been recurrence free for 6 months after surgery. COCs with AOT-like features are rare, and reflect the multipotentiality and complexity of the inductive effects of the odontogenic epithelium with the ectomesenchyme. Enucleation seems to be the most indicated treatment, similar to classical COC (AU)

As lesões odontogênicas são um grupo heterogêneo de patologias que apresentam diferenças no seu comportamento biológico, e ocorrência de interações indutivas variáveis. O cisto odontogênico calcificante (COC), ou cisto de Gorlin, é um exemplo bem conhecido destas lesões. Descrevemos um caso de COC com áreas adenomatóides e destacamos a sua diversidade morfológica. Paciente do sexo masculino, 60 anos de idade, apresentou um aumento de volume na região anterior da mandíbula. A radiografia panorâmica revelou uma lesão bem definida, unilocular e radiolúcida associada a uma reabsorção radicular importante. A enucleação completa da lesão foi realizada e os achados histopatológicos preencheram os critérios para o diagnóstico de COC, embora o cisto exibisse características adenomatóides pouco usuais. O paciente permanece livre de recidivas durante 6 meses após a cirurgia. Os COCs com características adenomatóides são raros, e refletem a multipotencialidade e complexidade dos efeitos indutivos do epitélio odontogênico com o ectomesênquima. A enucleação parece ser o tratamento mais indicado, semelhante ao COC clássico. (AU)

Differential protein expression of osteoclastogenic factors in odontogenic cysts and tumors.

The osteolytic activity of odontogenic cysts and tumors is directly associated with their growth and aggressiveness. The influence of proteins expressed by epithelial and mesenchymal cells on this biological event differs between indolent cystic lesions, aggressive cystic lesions, and odontogenic tumors. The objective of this study was to compare the immunohistochemical expression of factors that stimulate (receptor activator of nuclear factor kappa-Β ligand - RANKL, cathepsin K - CatK and matrix metallopeptidase 8 - MMP-8) and inhibit (osteoprotegerin - OPG) osteoclastogenesis between dentigerous cyst (DC), glandular odontogenic cyst (GOC), odontogenic keratocyst (OKC), and ameloblastoma (AB). Paraffin-embedded sections of nine DCs, nine GOCs, 20 OKCs, 21 ABs, and four dental follicles (DFs) were subjected to immunohistochemistry. Immunoreactivity was analyzed semiquantitatively and quantitatively in epithelium and connective tissue, respectively. The proteins were immunoexpressed in epithelial and mesenchymal cells of all lesions studied. The expression of RANKL and CatK was higher in OKC, AB, and GOC (p<0.005). Higher expression of OPG was found in DF and DC compared to the other markers (p<0.005). MMP-8 expression was high in GOC and OKC. This study demonstrated the differential expression of factors that inhibit and stimulate bone resorption during the development of DC, GOC, OKC, and AB. Higher expression of RANKL and CatK was observed in more aggressive lesions. OPG appears to be one of the molecules responsible for the slower growth of DC.

Differential protein expression of osteoclastogenic factors in odontogenic cysts and tumors

Abstract: The osteolytic activity of odontogenic cysts and tumors is directly associated with their growth and aggressiveness. The influence of proteins expressed by epithelial and mesenchymal cells on this biological event differs between indolent cystic lesions, aggressive cystic lesions, and odontogenic tumors. The objective of this study was to compare the immunohistochemical expression of factors that stimulate (receptor activator of nuclear factor kappa-Β ligand - RANKL, cathepsin K - CatK and matrix metallopeptidase 8 - MMP-8) and inhibit (osteoprotegerin - OPG) osteoclastogenesis between dentigerous cyst (DC), glandular odontogenic cyst (GOC), odontogenic keratocyst (OKC), and ameloblastoma (AB). Paraffin-embedded sections of nine DCs, nine GOCs, 20 OKCs, 21 ABs, and four dental follicles (DFs) were subjected to immunohistochemistry. Immunoreactivity was analyzed semiquantitatively and quantitatively in epithelium and connective tissue, respectively. The proteins were immunoexpressed in epithelial and mesenchymal cells of all lesions studied. The expression of RANKL and CatK was higher in OKC, AB, and GOC (p<0.005). Higher expression of OPG was found in DF and DC compared to the other markers (p<0.005). MMP-8 expression was high in GOC and OKC. This study demonstrated the differential expression of factors that inhibit and stimulate bone resorption during the development of DC, GOC, OKC, and AB. Higher expression of RANKL and CatK was observed in more aggressive lesions. OPG appears to be one of the molecules responsible for the slower growth of DC.

Simultaneous presentation of juvenile ossifying fibroma in the maxilla and mandible: a case report.

INTRODUCTION: Juvenile ossifying fibroma (JOF) is a controversial and uncommon lesion that has been distinguished from the larger group of ossifying fibromas because of distinct clinical features and some morphological peculiarities. Furthermore, JOF shows an aggressive biological behavior that has led researchers to consider it a benign neoplasm, resulting in its differential diagnosis with important benign and malignant bone neoplasms. PRESENTATION OF CASE: This study describes a case of synchronous presentation of JOF in the mandible and maxilla of a young patient. In addition, the literature was reviewed to identify clinical-pathologic features and possible factors that could help establish the correct diagnosis. A 26-year-old male patient presented simultaneously a lesion affecting the body, angle and ramus of the left mandible and another lesion in the left maxilla. Both lesions were well delimited and radiolucent, being unilocular in the maxilla and multilocular in the mandible. The mandibular lesion was partially resected and the maxillary lesion was submitted to curettage. The diagnosis was JOF. DICUSSION: A delay in seeking medical care and a late diagnosis can have serious consequences for the postoperative functional and esthetic outcome. Much care should be taken during establishment of this diagnosis since an equivocal diagnosis can have serious consequences for the patient in terms of treatment. CONCLUSION: After 1 year, the patient shows no signs or symptoms of recurrence of the lesions and was referred for reconstructive surgery of the mandible. An early and correct diagnosis is necessary to permit the best therapeutic management.

Tumor de célula granular em cavidade oral: relato de caso / Granular cell tumor in oral cavity: case report

Introdução: O tumor de células granulares (TCG) é uma neoplasia benigna de tecido mole incomum que acomete principalmente mulheres na quarta e sexta década de vida. A lesão possui predileção pela região de cabeça e pescoço, sendo a superfície dorsal da língua o local de maior acometimento. Clinicamente, apresenta-se como um nódulo submucoso firme, de coloração semelhante a mucosa ou levemente amarelada, de crescimento lento e assintomático. O objetivo deste trabalho é relatar um caso de TCG apresentando suas características clínicas, histopatológicas bem como os possíveis diagnósticos diferenciais. Relato de caso: Paciente sexo feminino, 46 anos de idade, apresentando nódulo localizado no bordo lateral posterior da língua. Ao exame intraoral foi possível observar tumefação firme à palpação, com coloração amarelada, medindo aproximadamente 1cm no seu maior diâmetro. Baseado na hipótese diagnóstica de lipoma, foi realizada uma biópsia excisional. A análise histopatológica revelou características morfológicas compatíveis com o TCG. Considerações finais: O Cirurgião-Dentista deve conhecer os diagnósticos diferenciais clínicos e histopatológicos, uma vez que a conduta terapêutica pode ser distinta em alguns casos... (AU)

Introduction: Granular cell tumor (GCT) is a benign neoplasm of uncommon soft tissue that mainly affects women in the fourth and sixth of life. The lesion has a predilection for the head and neck region, and the dorsal surface of the tongue is the site of major involvement. Clinically, it presents as a firm, mucosal or slightly yellowish, slowly growing, asymptomatic submucosal nodule. The objective of this work is to report a case of GCT presenting its clinical, histopathological and possible differential diagnoses. Case report: A 46-year-old female patient with a nodule located on the posterior lateral border of the tongue. On intraoral examination, it was found on a table, with a yellowish color, measuring approximately 1cm in its largest diameter. Based on the diagnostic hypothesis of lipoma, an excisional biopsy was performed. A histopathological analysis revealed morphological characteristics compatible with GCT. Final considerations: The Dentist should know the differential clinical and histopathological diagnoses, since the therapeutic behavior may be different in some cases... (AU)

Actinomycosis is not Frequent in the Periapex But is a Persistent Lesion.

Periapical actinomycosis caused by a gram-positive anaerobic pathogen characterizes a typical extra-radicular infection. This study determined the frequency and correlated the content of bacteria colonies with the of periapical actinomycosis size. The study comprised a total of 218 periapical lesions (PL) (cysts, granulomas or abscess). The specimens embedded in paraffin were sliced into 4-µm sections and stained with hematoxylin-eosin, Gram, Periodic Acid-Schiff (PAS) and Grocott's stain. The presence of bacterial colonies composed of filamentous structures labeled with the histochemical stains were described as Actinomyces, and for each case, the bacterial colonies were counted and measured. The correlation between the number and size of bacterial colonies and the size of PL was tested using Pearson's adjusted correlation coefficient. From 218 PL, bacterial colonies were identified in 64 biopsies. Seven cases (0.3%) fulfill the criteria for diagnosis of periapical actinomycosis. All of cases were therapy-resistant and did not showed periapical repair after 12 months of follow-up. Periapical surgery or dental extraction was performed. The correlation test indicated no correlation between the number of bacterial colonies and the lesion size (p=0.752, r=-0.148). However, a larger bacterial colony size generally resulted in a larger periapical lesion (P=0.000, r=0.657). The frequency of periapical actinomycosis was low, and this lesion should be included in the differential diagnosis of PL. The size of the Actinomyces colonies seemed to contribute to increase the size of the periapical lesion.

Actinomycosis is not Frequent in the Periapex But is a Persistent Lesion

Abstract Periapical actinomycosis caused by a gram-positive anaerobic pathogen characterizes a typical extra-radicular infection. This study determined the frequency and correlated the content of bacteria colonies with the of periapical actinomycosis size. The study comprised a total of 218 periapical lesions (PL) (cysts, granulomas or abscess). The specimens embedded in paraffin were sliced into 4-µm sections and stained with hematoxylin-eosin, Gram, Periodic Acid-Schiff (PAS) and Grocott's stain. The presence of bacterial colonies composed of filamentous structures labeled with the histochemical stains were described as Actinomyces, and for each case, the bacterial colonies were counted and measured. The correlation between the number and size of bacterial colonies and the size of PL was tested using Pearson's adjusted correlation coefficient. From 218 PL, bacterial colonies were identified in 64 biopsies. Seven cases (0.3%) fulfill the criteria for diagnosis of periapical actinomycosis. All of cases were therapy-resistant and did not showed periapical repair after 12 months of follow-up. Periapical surgery or dental extraction was performed. The correlation test indicated no correlation between the number of bacterial colonies and the lesion size (p=0.752, r=-0.148). However, a larger bacterial colony size generally resulted in a larger periapical lesion (P=0.000, r=0.657). The frequency of periapical actinomycosis was low, and this lesion should be included in the differential diagnosis of PL. The size of the Actinomyces colonies seemed to contribute to increase the size of the periapical lesion.

Resumo A actinomicose periapical causada por um patógeno anaeróbio Gram positivo caracteriza uma infecção extra-radicular típica. Esse estudo determinou a frequência e correlacionou o conteúdo das colônias bacterianas com o tamanho das actinomicoses periapicais. O estudo compreendeu um total de 218 lesões periapicais (LPs) (cistos, granulomas ou abscessos). Os espécimes embebidos em parafina foram cortados em secções de 4-µm e corados com hematoxilina-eosina, Gram, ácido periódico de Schiff (PAS) e coloração de Grocott. A presença de colônias bacterianas compostas por estruturas filamentosas marcadas com os corantes histoquímicos foram descritas como Actinomyces, e para cada caso, as colônias bacterianas foram contadas e mensuradas. A correlação entre o número e tamanho das colônias bacterianas e o tamanho das LPs foi testado usando o coeficiente de correlação ajustado de Pearson. De 218 LPs, colônias bacterianas foram identificadas em 64 biópsias. Sete casos (0,3%) preencheram os critérios para o diagnóstico de actinomicose periapical. Todos os casos foram resistentes à terapia e não mostraram reparo periapical após 12 meses de acompanhamento. Cirurgia periapical ou extração dental foi realizada. O teste de correlação indicou nenhuma correlação entre o número de colônias bacterianas e o tamanho da lesão (p=0.752, r=-0.148). Entretanto, uma maior colônia bacteriana geralmente resultou em uma maior lesão periapical (p=0.000, r=0.657). A frequência de actinomicose periapical foi baixa e esta lesão deve ser incluída no diagnóstico diferencial das LPs. O tamanho das colônias de Actinomyces pareceu contribuir para o aumento no tamanho da lesão periapical.

Pleomorphic adenomas of the salivary glands: retrospective multicentric study of 130 cases with emphasis on histopathological features.

Pleomorphic adenoma (PA) is the most frequent benign epithelial lesion of salivary gland origin, showing great histopathological diversity. The aim of this study was to perform a retrospective analysis, with emphasis on histopathologic features of PA of salivary glands. Clinical and histopathologic characteristics of 130 cases of minor and major salivary glands PAs from three Brazilian reference centers were studied. Higher frequency of PAs was observed in female (55.4 %) subjects, with mean age of 49.7 years. The most common affected site was palate (64.5 %) for the PAs of minor salivary glands and parotid for cases affecting major glands (86.2 %). Microscopically, most cases were classified as classic PAs (50 %). Incomplete capsule was observed in 36.2 % of the cases, while 47.2 % showed capsular infiltration. Rounded (66.9 %), angular (49.2 %), oval (46.2 %) and plasmacytoid (39.2 %) cells were widely observed, as well as fibrous (73.8 %) and myxoid (69.2 %) stroma, squamous metaplasia (25.4 %) and cystic degeneration (43.1 %). Crystalloids (3.1 %), increased mitotic activity (5.4 %) and vascular invasion (2.3 %) were rarely observed. PAs arising in minor salivary glands were associated with incomplete capsules, spindle, oval, angular, plasmacytoid and pleomorphic cells, fibrous and hyaline stroma, cystic degeneration, squamous metaplasia and pleomorphism (p < 0.05). No association between capsular features and histological subtype was noted (p ≥ 0.05). These results confirm the findings of previous studies regarding major clinicopathological features of pleomorphic adenomas; and highlighted some important morphologic characteristics like the capsule, vascular invasion, pleomorphism and increased mitotic activity, which can reflect the biological behavior of these tumors.

Histochemical and immunohistochemical differences between solitary oral fibroma and fibrous papule of the face.

BACKGROUND:: The morphological similarities between fibrous papules of the face and multiple sporadic oral fibromas were mentioned long ago and a relationship between them has been reported in the literature. OBJECTIVE:: The aim of this study was to evaluate the participation of mast cells, elastin and collagen in a series of oral fibromas and fibrous papules of the face in order to better understand the possible role of these factors in fibrosis and the formation of these lesions. METHODS:: Thirty cases of oral fibroma involving the buccal mucosa and 30 cases of fibrous papules of the face were selected. Tissue samples were submitted to picrosirius red staining and immunohistochemistry using anti-elastin and anti-tryptase antibodies. RESULTS:: The percentage of tryptase-positive mast cells and expression of elastin were higher in cases of fibrous papules of the face (p < 0.05). In contrast, a higher intensity of collagen deposition was observed in oral fibromas. The results showed mast cell accumulation and higher elastin synthesis in fibrous papules of the face, and mast cell accumulation with higher collagen fiber synthesis in oral fibromas. CONCLUSION:: These findings support the hypothesis that mast cells influence the development and growth of these lesions through different mechanisms.

Histochemical and immunohistochemical differences between solitary oral fibroma and fibrous papule of the face

Abstract: Background: The morphological similarities between fibrous papules of the face and multiple sporadic oral fibromas were mentioned long ago and a relationship between them has been reported in the literature. Objective: The aim of this study was to evaluate the participation of mast cells, elastin and collagen in a series of oral fibromas and fibrous papules of the face in order to better understand the possible role of these factors in fibrosis and the formation of these lesions. Methods: Thirty cases of oral fibroma involving the buccal mucosa and 30 cases of fibrous papules of the face were selected. Tissue samples were submitted to picrosirius red staining and immunohistochemistry using anti-elastin and anti-tryptase antibodies. Results: The percentage of tryptase-positive mast cells and expression of elastin were higher in cases of fibrous papules of the face (p < 0.05). In contrast, a higher intensity of collagen deposition was observed in oral fibromas. The results showed mast cell accumulation and higher elastin synthesis in fibrous papules of the face, and mast cell accumulation with higher collagen fiber synthesis in oral fibromas. Conclusion: These findings support the hypothesis that mast cells influence the development and growth of these lesions through different mechanisms.

Epidemiological survey of mucus extravasation phenomenon at an oral pathology referral center during a 43 year period / Levantamento epidemiológico de fenômeno de extravasamento de muco de um centro de referência em patologia oral por um período de 43 anos

ABSTRACT INTRODUCTION: Mucoceles are common benign pseudocystic lesions of the oral cavity; their main etiological factors are trauma and ductal obstruction. Two histological patterns are found: mucus retention phenomenon (MRP) and mucus extravasation phenomenon (MEP). Mucus extravasation phenomenon is the more common histological subtype and it mainly affects the lower lip. The knowledge of its main clinical features and management is important to assist health professionals in clinical practice. OBJECTIVE: This study aimed to determine the relative frequency and distribution of oral mucoceles in an oral pathology reference center. METHODS: Cross-sectional historical study that analyzed all cases pathologically diagnosed as mucus extravasation phenomenon by the department of anatomic pathology of an oral pathology referral center from June of 1970 to May of 2014, considering the clinical characteristics of the lesion and those relating to the patient. SPSS v. 20.0 software for Windows was used for descriptive analysis. RESULTS: During 43 years, 719 cases of mucus extravasation phenomenon (54.7% men and 45.3% women) were registered, with the lower lip as the most commonly affected site (n = 484; 67.3%). The average age of patients was 20.8 years (SD ± 14.4) with a peak occurrence in the second decade of life. Most professionals had oral mucocele/ranula (n = 606; 84.3%) as the initial clinical impression. CONCLUSION: Mucus extravasation phenomenon is a lesion that primarily affects young patients, affecting mainly the lower lip, and is commonly found in oral diagnostic services.

Resumo Introdução: Mucoceles são lesões pseudocísticas benignas comuns da cavidade oral, que possuem como principais fatores etiológicos trauma ou obstrução ductal. Dois padrões histopatológicos são encontrados: fenômeno de retenção de muco (FRM) e fenômeno de extravasamento de muco (FEM). O FEM é o subtipo histológico mais comum e tem como principal local de acometimento o lábio inferior. O conhecimento acerca de suas principais características clínicas e formas de tratamento se faz importante para auxiliar profissionais da saúde na prática clínica. Objetivo: Este trabalho objetivou determinar a frequência relativa e a distribuição das mucoceles orais em um centro de referência em patologia oral. Método: Estudo transversal de caráter histórico, no qual foram analisados os casos diagnosticados histopatologicamente como FEM pelo serviço de anatomia patológica de um centro de referência em patologia oral no período de junho de 1970 a maio de 2014, considerando-se variáveis clínicas da lesão e relativas ao paciente. O programa estatístico SPSS 20.0 for Windows foi utilizado para a análise descritiva dos dados. Resultados: Durante 43 anos foram observados 719 casos de FEM (54,7% homens e 45,3% mulheres), sendo o lábio inferior (n = 484; 67,3%) o local de principal acometimento. A média de idade dos pacientes foi de 20,8 anos (DP ± 14,4), com pico de ocorrência na segunda década de vida. A maioria dos profissionais teve mucocele oral/rânula (n = 606; 84,3%) como primeira hipótese clínica. Conclusão: O FEM é uma lesão que afeta principalmente pacientes jovens, acometendo preferencialmente o lábio inferior, sendo comumente encontrada nos serviços de diagnóstico oral.

Epidemiological survey of mucus extravasation phenomenon at an oral pathology referral center during a 43 year period.

INTRODUCTION: Mucoceles are common benign pseudocystic lesions of the oral cavity; their main etiological factors are trauma and ductal obstruction. Two histological patterns are found: mucus retention phenomenon (MRP) and mucus extravasation phenomenon (MEP). Mucus extravasation phenomenon is the more common histological subtype and it mainly affects the lower lip. The knowledge of its main clinical features and management is important to assist health professionals in clinical practice. OBJECTIVE: This study aimed to determine the relative frequency and distribution of oral mucoceles in an oral pathology reference center. METHODS: Cross-sectional historical study that analyzed all cases pathologically diagnosed as mucus extravasation phenomenon by the department of anatomic pathology of an oral pathology referral center from June of 1970 to May of 2014, considering the clinical characteristics of the lesion and those relating to the patient. SPSS v. 20.0 software for Windows was used for descriptive analysis. RESULTS: During 43 years, 719 cases of mucus extravasation phenomenon (54.7% men and 45.3% women) were registered, with the lower lip as the most commonly affected site (n=484; 67.3%). The average age of patients was 20.8 years (SD±14.4) with a peak occurrence in the second decade of life. Most professionals had oral mucocele/ranula (n=606; 84.3%) as the initial clinical impression. CONCLUSION: Mucus extravasation phenomenon is a lesion that primarily affects young patients, affecting mainly the lower lip, and is commonly found in oral diagnostic services.

Epithelioid hemangioma in the oral mucosa ­ A case report.

Introduction: Epithelioid hemangioma is an uncommon benign vasoproliferative neoplasm that usually manifests as multiple red nodules in middle-aged adults Case Outline: 52-year-old male patient presented with a one-year history of a nodular lesion in the left buccal mucosa measuring 3 cm. The clinical hypothesis was lipoma. An excisional biopsy revealed a circumscribed lesion composed of lobules of vessels with perceptible or poor lumina, associated with a prominent inflammatory infiltrate consisting of eosinophils, histiocytes and chronic inflammatory cells. The endothelial cells composing the lesion had an epithelioid morphology and contained abundant eosinophilic cytoplasm. Immunohistochemistry for CD34, factor VIII, collagen IV, alpha-smooth muscle actin, and mast cells, as well as histochemical staining with Weigert's orcein were performed. Conclusion: Vascular proliferations of soft tissues are a diverse and morphologically complex group of lesions that are difficult to diagnose. This report presents a case of oral epithelioid hemangioma, highlighting relevant morphological and immunohistochemical features that could help distinguish this condition from other neoplasms.

Effect of low-level laser irradiation on proliferation and viability of human dental pulp stem cells.

A positive effect of low-level laser irradiation (LLLI) on the proliferation of some cell types has been observed, but little is known about its effect on dental pulp stem cells (DPSCs). The aim of this study was to identify the lowest energy density able to promote the proliferation of DPSCs and to maintain cell viability. Human DPSCs were isolated from two healthy third molars. In the third passage, the cells were irradiated or not (control) with an InGaAlP diode laser at 0 and 48 h using two different energy densities (0.5 and 1.0 J/cm²). Cell proliferation and viability and mitochondrial activity were evaluated at intervals of 24, 48, 72, and 96 h after the first laser application. Apoptosis- and cell cycle-related events were analyzed by flow cytometry. The group irradiated with an energy density of 1.0 J/cm² exhibited an increase of cell proliferation, with a statistically significant difference (p < 0.05) compared to the control group at 72 and 96 h. No significant changes in cell viability were observed throughout the experiment. The distribution of cells in the cell cycle phases was consistent with proliferating cells in all three groups. We concluded that LLLI, particularly a dose of 1.0 J/cm², contributed to the growth of DPSCs and maintenance of its viability. This fact indicates this therapy to be an important future tool for tissue engineering and regenerative medicine involving stem cells.

Effect of laser therapy on laryngeal carcinoma cell proliferation(H Ep-2)

Objective: to evaluate the effect of 660nm and 780 nm laser therapy, with dose of 6.3 J/cm² and 25 mW power, either associated with nutritional stress or not, on laryngeal epidermoid carcinoma cell proliferation (H.Ep. 2). Material and Methods: the H.Ep.2 cells were placed in a culture flask and frozen in fetal bovine serum (FBS) at -80°C, with different concentrations of the medium: 5% and 10%. Laser therapy was started 24 h after cell subculturing and performed at time intervals of 6, 12, 24, 48 and 72 hours after the first irradiation, in a period of five days. After this, cell viability was verified using the MTT method. Means and standard deviation were obtained, and the Student's-t and F (ANOVA) statistical tests were used, with Tukey or Tamanhe comparisons. Results: The group subjected to 780 nm laser showed significant differences (p 0.05). The time influenced the growth of all cultures. Conclusion: low level laser interfered in cell proliferation and this effect could be determined by the wavelength used and the nutritional status of the cells.

Low-level laser irradiation induces in vitro proliferation of mesenchymal stem cells.

OBJECTIVE: To evaluate the effect of low-level laser irradiation on the proliferation and possible nuclear morphological changes of mouse mesenchymal stem cells. METHODS: Mesenchymal stem cells derived from bone marrow and adipose tissue were submitted to two applications (T0 and T48 hours) of low-level laser irradiation (660 nm; doses of 0.5 and 1.0 J/cm2). The trypan blue assay was used to evaluate cell viability, and growth curves were used to analyze proliferation at zero, 24, 48, and 72 hours. Nuclear alterations were evaluated by staining with DAPI (4'-6-diamidino-2-phenylindole) at 72 hours. RESULTS: Bone marrow-derived mesenchymal stem cells responded to laser therapy in a dose-dependent manner. Higher cell growth was observed when the cells were irradiated with a dose of 1.0 J/cm2, especially after 24 hours (p<0.01). Adipose-derived mesenchymal stem cells responded better to a dose of 1.0 J/cm2, but higher cell proliferation was observed after 48 hours (p<0.05) and 72 hours (p<0.01). Neither nuclear alterations nor a significant change in cell viability was detected in the studied groups. CONCLUSION: Low-level laser irradiation stimulated the proliferation of mouse mesenchymal stem cells without causing nuclear alterations. The biostimulation of mesenchymal stem cells using laser therapy might be an important tool for regenerative therapy and tissue engineering.

Low-level laser irradiation induces in vitro proliferation of mesenchymal stem cells / Laser de baixa intensidade induz à proliferação in vitro de células-tronco mesenquimais

Objective : To evaluate the effect of low-level laser irradiation on the proliferation and possible nuclear morphological changes of mouse mesenchymal stem cells. Methods : Mesenchymal stem cells derived from bone marrow and adipose tissue were submitted to two applications (T0 and T48 hours) of low-level laser irradiation (660nm; doses of 0.5 and 1.0J/cm2). The trypan blue assay was used to evaluate cell viability, and growth curves were used to analyze proliferation at zero, 24, 48, and 72 hours. Nuclear alterations were evaluated by staining with DAPI (4’-6-diamidino-2-phenylindole) at 72 hours. Results : Bone marrow-derived mesenchymal stem cells responded to laser therapy in a dose-dependent manner. Higher cell growth was observed when the cells were irradiated with a dose of 1.0J/cm2, especially after 24 hours (p<0.01). Adipose-derived mesenchymal stem cells responded better to a dose of 1.0J/cm2, but higher cell proliferation was observed after 48 hours (p<0.05) and 72 hours (p<0.01). Neither nuclear alterations nor a significant change in cell viability was detected in the studied groups. Conclusion : Low-level laser irradiation stimulated the proliferation of mouse mesenchymal stem cells without causing nuclear alterations. The biostimulation of mesenchymal stem cells using laser therapy might be an important tool for regenerative therapy and tissue engineering. .

Objetivo : Avaliar o efeito da terapia com laser de baixa intensidade sobre a proliferação e as possíveis alterações morfológicas nucleares em células-tronco mesenquimais de camundongos. Métodos : Células-tronco mesenquimais derivadas da medula óssea e do tecido adiposo foram submetidas a duas aplicações (T0 e T48 horas) de laser de baixa intensidade (660nm; doses de 0,5 e 1,0J/cm2). O ensaio de azul de tripan foi utilizado para a avaliação da viabilidade celular, e curvas de crescimento foram usadas para avaliar a proliferação das células em zero, 24, 48, e 72 horas. Alterações nucleares foram avaliadas por coloração com DAPI (4-6-diamidino-2-fenilindolo) em 72 horas. Resultados : As células-tronco mesenquimais derivadas da medula óssea responderam a terapia com laser de forma dose-dependente. Um maior crescimento celular foi observado quando as células foram irradiadas com dose de 1,0J/cm2, especialmente depois de 24 horas (p<0,01). As células-tronco mesenquimais derivadas do tecido adiposo responderam melhor à dose de 1,0J/cm2, com maior proliferação após 48 (p<0,05) e 72 horas (p<0,01). Nem alterações nucleares nem a mudança significativa na viabilidade celular foi detectada nos grupos estudados. Conclusão : Laser de baixa intensidade estimulou a proliferação de células-tronco mesenquimais sem causar alterações nucleares. A bioestimulação de células-tronco mesenquimais por laserterapia pode ser uma ferramenta importante para a terapia regenerativa e a engenharia tecidual. .