Alan Roger dos Santos Silva

Patterns of Demineralization and Dentin Reactions in Radiation-Related Caries

Radiation-related caries is a unique form of rampant decay and is a complication of head and neck radiotherapy that frequently causes generalized dental destruction and impairs quality of life in cancer patients. The aim of this study was to investigate the patterns of demineralization of caries in irradiated patients and to establish whether direct radiogenic damage to the dentition might be important in the progression of radiation-related caries. Teeth from patients who had concluded radiotherapy were examined histologically by polarized light microscopy, and the ultrastructure was examined by scanning backscattered electron microscopy. Cervical caries and incisal caries, a very unusual sort of lesion, were widely detected. Additionally, diffuse brown discoloration of the smooth surface of enamel was frequently observed. Polarized light microscopy suggested that these areas were incipient caries. Evidence of normal odontoblast function was observed in the detection of reactionary dentin and intratubular dentin deposition. In conclusion, radiation-related caries seems to have the same morphological and demineralization pattern as ordinary caries, with the presence of demineralized dentin, a translucent zone, dentin dead tracts, reactionary dentin and intratubular dentin deposition. Based on these findings, direct radiogenic destruction of the teeth seems to be not essential to the microscopic progression of radiation-related caries.

Clinical and histopathological analysis of oral squamous cell carcinoma in young people: A descriptive study in Brazilians

We retrospectively analysed the clinical and histological characteristics of oral squamous cell carcinoma (SCC) in a sample of Brazilian patients 45 years of age or less. Files from a single oral histopathological service were studied during the period 1990 to 2005 and the clinical data collected. The histological sections of the invasive part of each tumour were analysed and classified using the criteria of Bryne et al. A total of 46 patients were selected, 36 (78%) of whom were white; 38 (83%) were male; and the most common site was the floor of the mouth (n=14, 30%) followed by the tongue (n=13, 28%). Most selected patients used tobacco and alcohol, and 43 were diagnosed as having clinical stages III and IV disease. Nine of the tumours (20%) were well differentiated, 23 were moderately differentiated, and the rest (n=14) were poorly differentiated. The characteristics of this group suggest that oral SCC in young patients does not behave differently from the oral SCC found in the overall population.

Radiation-related caries and early restoration failure in head and neck cancer patients. A polarized light microscopy and scanning electron microscopy study

IntroductionRadiation-related caries is a disease with high potential of teeth destruction in patients who have undergone radiotherapy in the head and neck region. Also, it is a challenge for dentistry due to high rates of recurrent caries and early restorations failure.PurposeThis study aims to analyze the early restoration failures in order to better understand the etiology of dental restorations reduced longevity in irradiated teeth.MethodsFifteen restored permanent teeth extracted from 11 patients who had finished head and neck radiotherapy were studied. Sections from each tooth were prepared and a qualitative description of the interface between restorations and dentin was performed by using polarized light microscopy and scanning electron microscopy.ResultsUnfavorable anatomical shape of restorations, residual caries, and secondary caries affecting dentin adjacent to restorative materials were widely found. The morphological patterns of these carious lesions were similar to conventional dentin lesions with superficial demineralized zone and translucent zone.ConclusionsEarly dental restoration failure in teeth affected by radiation-related caries may have the same etiological factors from ordinary dental restoration failure and direct radiogenic damage to dentition would not be essential to early restorations failure in radiation-related caries.

High incidence of DNA ploidy abnormalities and increased Mcm2 expression may predict malignant change in oral proliferative verrucous leukoplakia

To assess the DNA content of cases of oral proliferative verrucous leukoplakia (PVL) and correlate the DNA ploidy findings with the expression of Mcm2, geminin, and Ki67, and with clinicopathological data.

Distinctive aspects of oral hyaline ring granulomas

The hyaline ring granuloma is a distinct oral entity characterized as a foreign body reaction occurring either centrally or peripherally. The granulomas may assume different histological characteristics, possibly related to the length of time in the tissue, and adequate recognition is important to avoid misdiagnosis. The aim of this article was to report 3 cases of hyaline ring granulomas with distinctive clinical and histopathological aspects, discussing the reasons for the different histological findings.

Oral intraneural perineurioma: report of two cases

A perineurioma is a benign nerve sheath tumor that can be classified as intra- or extraneural. Intraneural perineuriomas (IPs) are restricted to peripheral nerve boundaries and are rarely seen in the oral region, with only five cases reported in the English-language literature so far.1–5 Some authors believe that perineurioma is associated with trauma, but this association is not well-established in the literature. An IP is a cylindrical enlargement of a peripheral nerve that is formed by spindle-shaped cells around the nerve axon and expresses epithelial membrane antigen (EMA).1–5 This tumor usually affects adolescents and young adults, and it is not accompanied by pain or great increases in tumor size.1–5 The aim of this paper is to report two additional cases of oral IP to increase the current knowledge on this lesion and to discuss its etiopathogenesis.

Unusual wooden foreign body in the palate.

We report a case of a palatal calcified foreign body simulating an odontogenic lesion. Surgical exploration revealed a calcified mass that was analysed under light microscopy and identified as a vegetal foreign body. Further scanning electron microscopy analysis revealed that the foreign body was a piece of wood. Hard palate foreign bodies have been reported previously, however, it seems that this is the first case of its kind.

Sensitizing mucoepidermoid carcinomas to chemotherapy by targeted disruption of cancer stem cells

Mucoepidermoid carcinoma (MEC) is the most common malignancy of salivary glands. The response of MEC to chemotherapy is unpredictable, and recent advances in cancer biology suggest the involvement of cancer stem cells (CSCs) in tumor progression and chemoresistance and radioresistance phenotype. We found that histone acetyltransferase inhibitors (HDACi) were capable of disrupting CSCs in MEC. Furthermore, administration of HDACi prior to Cisplatin (two-hit approach) disrupts CSCs and sensitizes tumor cells to Cisplatin. Our findings corroborate to emerging evidence that CSCs play a key role in tumor resistance to chemotherapy, and highlights a pharmacological two-hit approach that disrupts tumor resistance to conventional therapy.

Integrated Proteomics Identified Up-Regulated Focal Adhesion-Mediated Proteins in Human Squamous Cell Carcinoma in an Orthotopic Murine Model

Understanding the molecular mechanisms of oral carcinogenesis will yield important advances in diagnostics, prognostics, effective treatment, and outcome of oral cancer. Hence, in this study we have investigated the proteomic and peptidomic profiles by combining an orthotopic murine model of oral squamous cell carcinoma (OSCC), mass spectrometry-based proteomics and biological network analysis. Our results indicated the up-regulation of proteins involved in actin cytoskeleton organization and cell-cell junction assembly events and their expression was validated in human OSCC tissues. In addition, the functional relevance of talin-1 in OSCC adhesion, migration and invasion was demonstrated. Taken together, this study identified specific processes deregulated in oral cancer and provided novel refined OSCC-targeting molecules.

Fine needle aspiration cytology in the diagnosis of cervical tuberculosis and paracoccidioidomycosis.

Dear Editor, Fine needle aspiration cytology (FNAC) has been used for diagnosing tumours, infectious diseases and reactive disorders and can be useful for staging malignancies and monitoring recurrences. The chronic infectious conditions most associated with enlarged cervical lymph nodes include tuberculosis, actinomycosis, paracoccidioidomycosis (Pmycosis), leprosy and toxoplasmosis. Here, we describe two patients with systemic infectious diseases manifesting as cervical lymphadenopathy where the diagnosis was established by FNAC.