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Biomedical subjects

A Piattelli

Publications and source records attributed to A Piattelli.

At least 19 recordsLinked to original sources
PubMed1992

Symmetrical pulp obliteration in mandibular first molars.

Pulp obliteration is an extremely rare morphological type of pulp calcification, with calcified material completely occupying the pulp chamber and root canal spaces. The etiology of pulp obliteration may be trauma or systemic diseases such as secondary hyperparathyroidism. Pulp obliteration may also be seen in dental anomalies such as dentinogenesis imperfecta and dentinal dysplasia. In cases of pulp obliteration with periapical disease, the preferred treatment is surgery, while calcified canals without symptoms or periapical lesions are best left untreated.

Adolescent↗
PubMed1992

Distribution and phenotype of immune cells in normal human gingiva: active immune response versus unresponsiveness.

The oral cavity, and particularly the gingival mucosa, is continuously exposed to numerous food and bacterial plaque antigens, though evident immunologic reactions are uncommon. It is therefore possible that the mucosal associated lymphoid tissue (MALT) of this region is preferentially biased towards unresponsiveness, rather than immune cell activation. The distribution and phenotype of immune cells in normal human gingiva were examined. Their distribution varied, and high and low cellularity areas could be distinguished in the same specimen. The number of CD3 positive (CD3+) T lymphocytes was more than thrice higher in a high cellularity area. In both types of area, intraepithelial T lymphocytes were not activated. Moreover, they showed chromatin condensation and cell shrinkage characteristic of apoptosis. In the stroma of high cellularity areas, foci of cell activation and numerous B cells were present, suggesting a localized active immune response. The vast majority of intraepithelial and stromal T lymphocytes expressed the "memory" CD45RO+ phenotype. The absence of an immune response within the epithelium and the localized response in the stroma (probably due to the binding of memory T cells to antigens in a low affinity, cross-reactive fashion) may be a part of a protective mechanism against indiscriminate stimulation by a multitude of external antigens.

Adult↗
PubMed1992

Morphodifferentiation and histodifferentiation of the dental hard tissues in compound odontoma: a study of undemineralized material.

Dental hard tissues and mineralization at the enamel surface or in the ameloblastic epithelium were studied in 10 odontomas using undemineralized material. All the specimens showed a high degree of histo- and morphodifferentiation. Dentin formed the bulk of the tumors. Much of the enamel was prismatic and apparently normal and in almost every specimen were present enamel tufts and spindles. At greater magnification it could be seen that the prisms had a very irregular orientation. Cementum was mostly acellular. Calcified material formed focally in the intercellular portion of the enamel epithelium: this material showed a concentric layers arrangement.

Ameloblasts↗
PubMed1992

Generalized "complete" calcific degeneration or pulp obliteration.

Extensive calcification of the pulp is a pathologic condition that occurs as an answer to various factors (trauma, caries, periodontal disease). The increase in the amount of calcification may lead to partial or complete radiographic, but not microscopic, obliteration of the pulp chamber and root canals. Complete calcific degeneration (pulpal obliteration) may be found in two forms, generalized or localized. The generalized form which is presented in the present case report is probably part of the aging process.

Dental Pulp Calcification↗
PubMed1992

Bilateral maxillary and mandibular fourth molars. Report of a case.

Fourth molar do not occur very frequently. They tend to be unerupted or if they erupt may cause malalignment of the dentition or aesthetic problems. The preferred location is in the maxilla, and they may be normal or rudimentary and located either directly distal or distolingually to the maxillary third molar. Supernumerary molars should probably be extracted only when their presence is responsible for the failure of eruption or malalignment of permanent teeth.

Adult↗
PubMed1991

Immunoreactivity for interleukin 1-beta and tumor necrosis factor-alpha and ultrastructural features of monocytes/macrophages in periapical granulomas.

Interleukin 1 (IL-1) and tumor necrosis factor (TNF) have recently been shown to be involved in bone resorption, and because macrophages constitute a significant part of human periapical granulomas, it is reasonable to suspect that they may secrete IL-1 and TNF. The purpose of our investigation was to detect and characterize IL-1 beta- and TNF-alpha-producing cells in human periapical granulomas. Fresh tissue samples obtained during surgery from 10 patients with previously untreated teeth and histologically established periapical granulomas were studied with light and electron microscopy and with immunohistochemical analysis with monoclonal antibodies against IL-1 beta and TNF-alpha. There were very few IL-1 beta + and TNF-alpha + cells present in periapical granulomas, and the positive cells had monocyte/macrophage morphology. The IL-1 beta + cells were located mainly in areas of active exudation and were surrounded by and/or were in close contact with lymphoid cells, whereas TNF-alpha + cells were scattered and in contact with or near other inflammatory cells at the periphery of active granulation tissue. This suggests that the IL-1 beta + cells may act in a paracrine manner to activate lymphoid cells. The ultrastructural findings showed that only some macrophages are adapted to extracellular secretion rather than phagocytosis. These modified macrophages could be the major producers of interleukins in tissues. Occasionally, they have plasmacytic or plasmacytoid features resembling the so-called "plasmacytoid monocytes". Only a minor fraction of the monocytes/macrophages (representing about 40% of the inflammatory cells) is in an active cytokine-producing state.(ABSTRACT TRUNCATED AT 250 WORDS)

Bone Resorption↗
PubMed1991

Immune cells in periapical granuloma: morphological and immunohistochemical characterization.

Samples of periapical granulomas obtained from 12 patients were examined using light and electron microscopes and monoclonal antibodies. Monocytes/macrophages, lymphocytes, and plasma cells were nearly always the most abundant cell populations. Ultrastructural analysis showed close contacts between macrophages and cells of the lymphoid lineage, with the lymphoid cells frequently demonstrating blastic features. Immunohistochemical staining with the anti-interleukin 2 receptor antibody showed that the concentration of labeled cells was quite low. The vast majority were lymphocytes, though some mast cells were also labeled. Mast cells were chiefly located in perivascular areas and interleukin 2 receptor-positive mast cells were frequently associated with lymphoid cells. mast cells could be part of a negative feedback mechanism in the immune response. By releasing histamine, they would block the immune response and by absorbing interleukin 2 they would remove it as an immune system stimulant.

Antibodies, Monoclonal↗
PubMed1991

Ghost cells in compound odontoma: a study of undemineralized material.

Calcifications and ghost cells at the enamel surface or in the ameloblastic epithelium were studied in twelve odontomas using undemineralized material. Calcified material formed focally in the intercellular portion of the enamel epithelium: this material showed a concentric layers arrangement. Ghost cells were present in most of the odontomas. These ghost cells were epithelial cells which enlarged, became eosinophilic and underwent an aberrant type of keratinization with the formation of large masses of keratin, that didn't stain as deeply as normal keratin. These cells often showed karyolysis of the nucleus as keratinization progressed. Frequent was the appearance of dystrophic calcifications in individual cells or clusters of cells, characterized by extremely fine basophilic granularity. The outlines of these keratinized cells could often still be discerned, even if with some difficulty.

Ameloblasts↗
PubMed1991

Leiomyosarcoma of the oral cavity: report of two cases located on the lips.

The authors report 2 cases of leiomyosarcoma of the lips occurring in two elderly women. They review the incidence, the symptoms, the microscopic appearance, the differential diagnosis, the treatment and prognosis of this kind of tumor. It is a highly malignant neoplasm with a high rate of recurrences and metastases and should be treated with a radical resection and radical neck dissection when there is a metastatic node.

Aged↗
PubMed1991

Primary failure of eruption.

Failure of eruption may be due to mechanical interference or to a failure in the eruption mechanism of the tooth. The etiology of the primary failure of eruption is unknown, but it could be due to an alteration in either metabolism or blood flow to the periodontal ligament. Therapy of patients with this condition is extremely difficult; orthodontic treatment causes ankylosis and probably the only way to move unerupted teeth into occlusion is to reposition them surgically with a small segment alveolar osteotomy.

Adolescent↗
PubMed1991

Nevoid basal cell carcinoma syndrome. A case report.

Nevoid basal cell carcinoma syndrome is an autosomal dominant disorder and is characterized by a great variety of signs and symptoms. The most important are a characteristic facies, the occurrence of basal cell carcinomas and odontogenic keratocysts. In view of the neoplastic skin change, constant review of the patients is indicated. Any jaw film revealing two or more dentigerous or follicular cysts should alert the clinician to the possibility of this underlying syndrome.

Adult↗
PubMed1991

Pleomorphic rhabdomyosarcoma of the upper lip in an adult patient. Report of a case and review of the literature.

The author presents a case of a pleomorphic rhabdomyosarcoma of the lip, in an adult patient. It is an exceptional localisation on this site. RMS is a highly malignant neoplasm with a preferred location in the lower extremities. The treatment should consist of multimodal therapy with excision of the primary tumor, radiation and multidrug regimen. The overall 5-years survival varies from 35% to 65%.

Humans↗
PubMed1990

[The histopathological aspects of the calcifying odontogenic cyst].

Calcifying odontogenic cyst is rare; about 140 cases have been described in the literature. The problem of the proper classification of the calcifying odontogenic cyst has been discussed almost since its identification. Recently it has been concluded that the group of lesions designated as calcifying odontogenic cyst contained two entities, a cyst and a neoplasm.

Calcinosis↗