An expanded odontogenic myxoma in maxilla.

Odontogenic myxomas are considered to be a benign odontogenic tumor with locally aggressive behavior, non-metastasizing neoplasm of the jaw bones. It derives from the dental mesenchyme or periodontal ligament. Despite the benign nature of these lesions, there is a high rate of local recurrence after curettage alone and in certain cases requires adequate resection. This paper describes a case of a large odontogenic myxoma in the maxilla, emphasizing a discussion on the differential diagnosis related to radiological findings and the surgical treatment.

Cell proliferation and apoptosis in keratocystic odontogenic tumors.

OBJECTIVES: Keratocystic odontogenic tumors (KOTs), also known as odontogenic keratocysts, were recently classified as a benign neoplasia due to the aggressive clinical behavior. Although several studies have shown the high proliferative activity of the epithelial lining, few studies have evaluated apoptosis in KOTs. Therefore, the aim of this study is to evaluate and compare the proliferation index (PI) and the apoptotic index (AI) of the epithelial lining in sporadic KOTs, KOTs associated with the Nevoid Basal Cell Carcinoma Syndrome (NBCCS KOTs), and dentigerous cysts. MATERIAL AND METHODS: A total of 11 sporadic KOTs, 15 NBCCS KOTs, and 11 dentigerous cysts were evaluated. The PI was assessed by immunohistochemical detection of the cell proliferation marker Ki-67. The AI was assessed by morphological evaluation of sections stained by methyl green-pyronin. The TUNEL assay was used to confirm the occurrence of apoptosis. Differences in the PI and the AI between sporadic KOTs, NBCCS KOTs, and dentigerous cysts were analyzed using the Kruskal-Wallis test. Differences in the PI and the AI between the epithelial layers of each lesion were analyzed using the Wilcoxon test. RESULTS: The PI and AI were higher in sporadic and NBCCS KOTs than in dentigerous cysts. No difference in these indexes was observed between sporadic and NBCCS KOTs. In dentigerous cysts, the PI was higher in the basal layer. In sporadic and NBCCS KOTs, the PI was higher in suprabasal layer. No difference in the AI was observed between the basal layer and the suprabasal layer in the three lesions. The AI was higher in the superficial layer of sporadic and NBCCS KOTs. CONCLUSIONS: The present study demonstrates that the epithelial lining of KOTs shows a distinct pattern of cell proliferation and apoptosis, reflecting its high cell turnover and reinforcing its classification as an odontogenic tumor.

Advanced osteosarcoma of the maxilla: a case report.

Osteosarcomas are primary malignant bone tumours in which mesenchymal cells produce osteoid. It is generally the most common malignant bone neoplasm, although lesions of the jaw are uncommon. Osteosarcoma of the jaw (JOS) presents a lower incidence of metastasis and a better prognosis than osteosarcoma of the long bones. However, patients with JOS can exhibit advanced tumours, mainly when early diagnosis is not performed. This article reports on a case of an advanced osteosarcoma of the maxilla. A 38-year-old woman was referred for evaluation and treatment of recurrent fibrous dysplasia of the facial bones. The patient related that she had been diagnosed with fibrous dysplasia four years earlier and, since the first diagnosis, she was submitted to four surgical interventions, all followed by recurrences. The main clinical findings were redness and swelling of the facial skin, upper lip ulceration, and hard palate swelling. Computed tomography showed a large hyperdense mass in right maxilla extending to right orbit and left maxillary sinus. An incisional biopsy was performed and microscopic examination showed areas of osteoid and chondroid formation surrounded by a cellular stroma. The diagnosis of osteosarcoma was established and the patient was recommended for oncologic treatment. Unfortunately, she died six months after the diagnosis due to uncontrollable local spread.

Cell proliferation and apoptosis in ameloblastomas and keratocystic odontogenic tumors.

A high proliferative activity of the odontogenic epithelium in ameloblastoma (AM) and keratocystic odontogenic tumor (KOT) has been demonstrated. However, no previous study has simultaneously evaluated cell proliferation and apoptotic indexes in AM and KOT, comparing both lesions. The aim of this study was to assess and compare cell proliferation and apoptotic rates between these two tumors. Specimens of 11 solid AM and 11 sporadic KOT were evaluated. The proliferation index (PI) was assessed by immunohistochemical detection of Ki-67 and the apoptotic index (AI) by methyl green-pyronine and in situ DNA nick end-labelling methods. KOT presented a higher PI than AM (p<0.05). No statistically significant difference was found in the AI between AM and KOT. PI and AI were higher in the peripheral cells of AM and respectively in the suprabasal and superficial layers of KOT. In conclusion, KOT showed a higher cell proliferation than AM and the AI was similar between these tumors. These findings reinforce the classification of KOT as an odontogenic tumor and should contribute to its aggressive clinical behavior.

Cell proliferation and apoptosis in ameloblastomas and keratocystic odontogenic tumors

A high proliferative activity of the odontogenic epithelium in ameloblastoma (AM) and keratocystic odontogenic tumor (KOT) has been demonstrated. However, no previous study has simultaneously evaluated cell proliferation and apoptotic indexes in AM and KOT, comparing both lesions. The aim of this study was to assess and compare cell proliferation and apoptotic rates between these two tumors. Specimens of 11 solid AM and 11 sporadic KOT were evaluated. The proliferation index (PI) was assessed by immunohistochemical detection of Ki-67 and the apoptotic index (AI) by methyl green-pyronine and in situ DNA nick end-labelling methods. KOT presented a higher PI than AM (p<0.05). No statistically significant difference was found in the AI between AM and KOT. PI and AI were higher in the peripheral cells of AM and respectively in the suprabasal and superficial layers of KOT. In conclusion, KOT showed a higher cell proliferation than AM and the AI was similar between these tumors. These findings reinforce the classification of KOT as an odontogenic tumor and should contribute to its aggressive clinical behavior.

Uma elevada atividade proliferativa do epitélio odontogênico em ameloblastoma (AM) e tumor odontogênico ceratocístico (TOC) tem sido demonstrada. Entretanto, não há estudos prévios avaliando simultaneamente os índices de proliferação celular e apoptótico em AM e TOC, comparando ambas as lesões. O objetivo desse estudo foi avaliar e comparar os índices de proliferação celular e apoptótico entre esses dois tumores. Onze amostras deAM sólido e 11 amostras de TOC esporádico foram avaliadas. O índice de proliferação celular foi avaliado por meio da imunomarcação para o antígeno Ki-67 e o índice apoptótico pelas técnicas demetyl-green-pironina e TUNEL. O TOC apresentou um índice de proliferação celular maior que o AM (p<0,05). Nenhuma diferença estatística foi encontrada no índice apoptótico entre AM e TOC. Os índices de proliferação celular e apoptótico foram maiores nas células da camada periférica do AM e, respectivamente, nas camadas suprabasal e superficial do TOC. Em conclusão, o TOC apresentou proliferação celular maior que o AM e o índice apoptótico foi similar entre estes tumores. Estes achados reforçam a classificação do TOC como um tumor odontogênico e podem contribuir para o seu comportamento clínico agressivo.

Hypersensitivity to conventional and to nickel-free orthodontic brackets

The aim of this study was to evaluate the allergenic potential of orthodontic brackets, comparing the cutaneous sensitivity provoked by metals present in conventional metallic brackets to that provoked by brackets with a low concentration of nickel, known as "nickel-free". A sample was selected from 400 patients undergoing treatment in the orthodontic clinic of the Pontifical Catholic University of Minas Gerais (Belo Horizonte, MG, Brazil), in the period from the beginning of 2002 to the end of 2003. A cutaneous sensitivity patch test containing 5 percent nickel sulphate was used in 58 patients (30 males and 28 females), aged between 11 and 30, which were using fixed appliances with Morelli® brackets in both arches. In a second phase, 30 days later, a comparative test of cutaneous sensitivity was applied to the whole sample with two types of test specimens, in the form of a disc. Two alloys were tested: discs composed of the alloy used in the construction of conventional brackets and discs composed of a nickel-free alloy. The internal part of the forearm was chosen for testing, and 20 test specimens of each experiment (corresponding to the twenty brackets of a complete fixed appliance) were applied. Of the 58 patients evaluated, 16 patients were sensitive to the patch test with 5 percent nickel sulphate. Out of these 16 patients, 12 developed an allergic reaction to experiment 1 (test specimen with nickel), while in experiment 2, only 5 patients showed sensitivity to that sample. The McNemar test revealed that the nickel-free test specimens provoked less allergic reaction when compared with the conventional alloy (p = 0.016).

Este trabalho teve como objetivo avaliar a capacidade alergênica provocada pelos bráquetes ortodônticos, comparando a sensibilidade cutânea provocada pelos metais presentes nos bráquetes metálicos convencionais com a provocada por bráquetes com baixa concentração de níquel ("nickel-free"). A amostra foi selecionada dos 400 pacientes em tratamento da clínica de Ortodontia da Pontifícia Universidade Católica de Minas Gerais (Belo Horizonte, MG, Brasil), no período compreendido entre o início de 2002 e o final de 2003. A amostra consistiu de 58 pacientes (30 homens e 28 mulheres), com idades variando de 11 a 30 anos, os quais eram portadores de aparelho ortodôntico fixo Morelli® em ambos os arcos. Estes pacientes foram diagnosticados quanto à sensibilidade ao níquel, por meio da aplicação do "patch test" com sulfato de níquel a 5 por cento. Em uma segunda fase, trinta dias após o "patch test", comparou-se a sensibilidade cutânea provocada pelos metais presentes nos bráquetes convencionais e nos "Nickel Free", por meio de um teste de sensibilidade cutânea utilizando-se dois tipos de corpos-de-provas, em formato de disco, com a mesma composição destes bráquetes. A área de eleição para realização deste teste foi a parte interna do antebraço, sendo aplicados vinte corpos-de-prova de cada experimento (referente a uma boca completa de bráquetes). Dos 58 pacientes avaliados, 16 deles foram sensíveis ao "patch test" com sulfato de níquel a 5 por cento. Dentre estes 16 pacientes, 12 deles desenvolveram reação alérgica ao Experimento 1 (corpo-de-prova com níquel), enquanto que no Experimento 2 (corpo-de-prova "Niquel Free") apenas 5 pacientes apresentaram sensibilidade a esta amostra. O teste de McNemar revelou que os corpos-de-prova "nickel-free" provocaram menor reação alérgica quando comparados aos convencionais (p = 0.016).