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.

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.

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 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.

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.

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.

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.

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.

O uso da luz laser de baixa intensidade vem sendo utilizado como terapia coadjuvante ou de forma terapêutica isolada em várias especialidades odontológicas. Suas principais indicações incluem ação anti-inflamatória, analgésica e indutora da reparação tecidual. O poder cicatrizante do laser de baixa potência é discutido neste trabalho assim como os mecanismos de biomodulação e estimulação da mitose. Estas propriedades, já estudadas em células benignas, quando aplicadas em células neoplásicas malignas, abrem espaço para discussões. O objetivo do presente trabalho foi realizar uma revisão da literatura sobre os aspectos indutivos do laser no processo de proliferação celular principalmente no que se refere a estes mecanismos em células neoplásicas malignas.

Low energy laser has been used as an adjuvant therapy or as a therapeutic tool in many different areas of Dentistry. It is recognized by its anti-inflammatory and analgesic properties, and also as a tissue repair inductor. Low intensity laser property in stimulate cell proliferation during wound healing and its biomodulation mechanisms are discussed in this paper. These properties have already been established for cultured benign cells, but there is a controversy when extended to the spectrum of the malignant neoplastic process, normally generating great discussions. The objective of this work was to perform a literature review about the low intensity laser capacity in induce cell proliferation. The discussion is specially concerned about its effects on malignant cells.