Benign osteoblastoma is a bone tumour that seldom occurs in the facial bones. The objective of this article is to add one more case of this rare lesion to the academic literature and to provide a systematic review of previously published cases. A new case of benign osteoblastoma is presented and clinical, radiographic and microscopic aspects, as well as differential diagnosis, treatment and follow-up are discussed. The importance of the correct diagnosis of this type of lesion is stressed, since it presents a clinical, radiographic and microscopic similarity to other bone lesions, including malignant tumours, which may lead the professional into conducting the case in an improper manner.

The primary aim of this paper is to present clinical and radiographic aspects of odontogenic myxomas diagnosed at the Stomatology Clinic of Bauru School of Dentistry, University of São Paulo, Brazil and to compare them with data reported in a series published in the literature. A second objective is to report a clinical case of odontogenic myxoma in a 9-year-old patient in whom the lesion involved the anterior region of the maxilla. Dental records between 1975 and 2000 were reviewed and seven cases diagnosed as odontogenic myxoma were found in individuals aged from nine to 60 years. Of these, four occurred in women and three in men. The mandible was affected in five cases and the maxilla in two. All patients presented with asymptomatic swelling in the affected area. A mixed radiographic result was observed in five patients, while in two patients the lesion was completely radiolucent. The borders of the lesion were well-defined in six patients. In four cases there was dental displacement, although root resorption was not observed in any of these. The treatment of choice was surgical excision. Four cases did not recur during the period of follow-up, which varied from nine months to 19 years. It was concluded the clinico-radiographic study of odontogenic myxomas should be continually refined with the aim of offering the patient an appropriate treatment, since the lesion presents a high potential for recurrence. Abstract © Seer Publishing

External cervical root resorption is one of the disadvantages of the bleaching procedure. There are several mechanisms that may be responsible for causing resorption, such as the chemical and physical action of the utilized materials and the morphology of the cementoenamel junction. The purpose of this study was to investigate the presence of a communication between the pulp chamber and the external root surface. The investigation was carried out by means of pH tests and measurement of dye infiltration into cervical dentin after the bleaching procedure. Thirty-four human permanent incisors were submitted to endodontic treatment. The teeth were assigned to three experimental groups, according to the level at which the filling was cut, and to the sealing of the root canal entrance with glass ionomer cement. Sodium perborate and 30% hydrogen peroxide were utilized for bleaching. pH readings were carried out after 30 minutes, 24 h, 48 h and 72 h from the beginning of the procedure. The teeth were immersed in 0.5% basic fuchsin for 24 h in order to determine possible differences in the permeability of cervical dentin. The results revealed that pH tended to change when the root filling was cut at the entrance of the canal, when 2 mm of the filling were removed, and when the canal entrance was sealed with glass ionomer. Dentinal permeability increased in the three experimental groups, in comparison with the control group. These slight differences may suggest a communication between the pulp chamber and the external root surface.

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À FAPESP, Fundação de Amparo à Pesquisa do Estado de São Paulo, meus sinceros agradecimentos pela oportunidade de poder freqüentar o curso de Pós-Graduação e por financiar este trabalho de pesquisa. Aos Profs. do Departamento de Estomatologia e Cirurgia da FOB-