Comparison of radiographic measurements obtained with conventional an indirect digital imaging during endontic treatment

The aims of this study were to evaluate the quality of indirect digitized radiographic images taken during endodontic procedures and to compare the measurements recorded with this technique to those obtained from conventional radiographs. Two-hundred conventional periapical radiographs taken at the undergraduate Endodontics Clinic of the Dental School of Bauru were digitized. The conventional and indirect digitized images were compared by three examiners as to the quality and accuracy of the measurements recorded during endodontic treatment, in canal length determination, gutta-percha adaptation, lateral condensation and final obturation. The conventional radiographs were observed on a film viewer, surrounded by a dark card, and measured with magnifying glass and a millimeter ruler; the indirect digitized images were evaluated on the Digora® for Windows software, with free utilization of the bright/contrast tool. Unlike the conventional radiographic images, all indirect digitized images were considered as having a high quality. The distance between the filling material and the root apex was 0.117 mm larger, on average, for the Digora® system (

RADIOGRAPHIC EVALUATION OF PERIODONTAL BONE RESORPTION WITH PIXEL VALUE AND HISTOPATOLOGICAL ANALYSIS.

Avaliar radiograficamente a reabsorção óssea periodontal por meio do valor de pixel e sua comparação com o exame histopatológico foi o objetivo deste trabalho. Trinta ratos Wistar foram submetidos à indução de doença periodontal com fio de seda 3-0 ao redor do primeiro molar inferior direito e o lado esquerdo foi deixado como controle. O grupo 1 foi sacrificado após passados 7 dias, o grupo 2, após 14 dias e o grupo 3 após 28 dias. As hemimandíbulas dos 30 animais foram radiografadas em filmes radiográficos tamanho 2 e na placa fotoestimulável de fósforo do sistema Digora®. As radiografias convencionais foram digitalizadas em um scanner a laser. As peças foram processadas para cortes microscópicos e coradas em HE para análise. As médias dos valores dos pixels das áreas de doença e das áreas controle foram aferidos no programa ImageJ®. O teste ANOVA a dois critérios mostrou que os valores dos pixels das áreas de doença periodontal foram significantemente menores do ponto de vista estatístico, quando comparados às áreas de controle, tanto para as radiografias obtidas com o sistema Digora®, quanto para as digitalizadas. No entanto, a ANOVA a um critério das médias dos valores dos pixels das áreas de doença periodontal não mostrou diferença estatisticamente significante entre os diferentes períodos experimentais. A análise microscópica evidenciou perda óssea, com aumento de osteoclastos e diminuição da altura da crista óssea alveolar com o passar do período experimental. Como conclusão, a análise do valor de pixel de uma radiografia digital foi capaz de evidenciar perda óssea quando comparada com seus controles, mas falhou ao detectar as alterações ósseas progressivas que foram visualizadas microscopicamente.The aim of this research was to evaluate the pixel value modification in periodontal disease sites using direct digital radiography and digitalized radiography. Periodontal disease was induced by a 3-0 silk ligature in the inferior right first molars of thirty Wistar rats. The inferior left first molar was the control. The animals were divided into groups: 1- seven days; 2- fourteen days and 3- twenty eight days. The mandibles were removed and radiographed with film size 2 and in a photoestimulable phosphor plate (Digora®). Conventional radiographs were digitized in a laser scanner. The mandibles were processed and HE stained for histological analysis. The mean pixel values from the periodontal disease sites were measured by histogram analysis by the software ImageJ®. There was an ANOVA test statistic significant difference among the pixel values for disease sites when compared to the control sites in the three groups for Digora® and digitized images. However, there was no significant difference for the disease sites regardind the pixel values among experimental periods. The longer the experimental period, more severe was the bone loss visualized histologically. In conclusion, pixel value analysis in a digital radiographic image may evidence bone loss when compared to the controls, but failed in detecting the progressive bone loss microscopically visualized

Nerves in Oral Cancer: Mechanism of Interaction and Clinical Relevance

Patients with oral squamous cell carcinoma, the most common oral cancer, survive poorly. Perineural invasion (PNI), a microscopic feature showing cancer in nerves, is common in oral cancer and is associated with dismal survival. Consequently, PNI-positive tumors are treated aggressively. Surprisingly, PNI has not been established as an independent predictor of prognosis, and diagnostic criteria of PNI vary. Importantly, these criteria do not integrate the biology of cancer-nerve interactions. Moreover, much remains to be discovered about how nerves promote tumor progression, which varies with tumor type, type of innervation, and location. To address these knowledge gaps, we investigated the clinical significance of PNI and other neural phenotypes in oral cancer, and investigated the underlying mechanisms. Understanding how these mechanisms contribute to clinical outcomes is crucial for developing new treatment strategies to improve survival of patients with oral cancer. Our results from tumor specimens of 142 patients with oral cancer, demonstrate that PNI is an independent predictor of poor prognosis. Equally significant are our findings that patients with close nerve-tumor distance, large nerve(s), and high nerve density in the tumor bulk, survive poorly even in the absence of PNI. Clinical studies on the neural influence in oral cancer were integrated with mechanistic studies. Spatial transcriptomic analyses of PNI-positive and PNI-negative nerves in human oral cancer, interrogating >18,000 genes, showed that nerves in proximity to cancer cells exhibit demyelination, stress, and growth response changes that diminish with increasing nerve-tumor distance. These findings were validated in vitro and in human tissue. Together these studies show that multiple neural phenotypes including PNI, nerve-tumor distance, nerve diameter, and nerve density, are of clinical significance in progression of oral cancer. These translational studies substantiate our previous finding that cancer and nerves have biochemical interactions even in the absence of physical contact. To understand the mechanisms of communication between nerves and tumor, we first identified the type(s) of innervation associated with oral cancer, and then performed RNA sequencing and validation studies in vitro and in animal models. Most of the innervation in oral cancer is sensory. In mice, RNA sequencing of sensory ganglia innervating tumors, show an injury/regeneration-like nerve response to tumor, strikingly similar to our spatial transcriptomic findings in human cancer. Specifically, activating transcription factor 3 (Atf3) and galanin (Gal) were upregulated in nerves from mice with tumors. Interestingly, we previously showed that galanin induces progression of oral cancer via proliferation, invasion, and angiogenesis. Here we identified the mechanism by which cancer cells induce galanin release from neurons. IL-1beta and TNFalfa, cytokines secreted from oral cancer, induce galanin secretion from neuronal cells via ATF3, and stimulate axonogenesis. Consistent with these findings, in human oral cancer tissue specimens, GAP43, a marker of nerve growth, is highly expressed in nerves proximal to cancer, including PNI-positive nerves. Together, these findings show that cancer induces a regenerative phenotype in nerves. In turn, galanin induces ERK activation of cancer cells that in turn induces proliferation. In conclusion, interactions between oral cancer and nerves are governed by an injury-like mechanism that is dependent on nerve-tumor distance, with implications for both prognosis and treatment. Our work illuminates nerve-cancer interactions suggesting that cancer-induced nerve injury modulates axonogenesis, and supports re-classification of PNI based on nerve-tumor distance rather than current subjective criteria. We suggest incorporating nerve-tumor distance, nerve density, and nerve diameter to predict prognosis.PHDOral Health SciencesUniversity of Michigan, Horace H. Rackham School of Graduate Studieshttp://deepblue.lib.umich.edu/bitstream/2027.42/174397/1/ligiabs_1.pd