Characterization of an optically stimulated dosimeter for dentomaxillofacial dosimetry.

The objective of this study was to examine the suitability of optically stimulated luminescent dosimeters (OSLD) for point dosimetry of maxillofacial radiographic examinations. The dose response of OSLD nanoDot dosimeters was evaluated over the range of 10 μGy to 4900 μGy x-radiation. The angular dependence of the OSLD nanoDots was examined and compared with that of thermoluminescent dosimeter (TLD) chips. The concordance between OSDL- and TLD-measured absorbed doses at selected anatomic sites in an anthropomorphometric phantom was examined. OSLD-measured doses were not significantly different from the actual delivered dose, as determined by an ionization chamber. The dose response is linear over the dose response over the examined dose range. Angular variation of OSLD dosimeters ranged from 88% to 109%; however, the magnitude of this variation was not significantly different from that of TLDs. There was a good concordance between OSLD- and TLD-measured absorbed doses. The OSLD nanoDots dosimeter system performs as well as currently used TLD systems and effective dose estimates using this new system did not differ significantly from current TLD-based dose estimates.

被引量：1 发表：1970

The influence of cone-beam computed tomography and periapical radiographic evaluation on the assessment of periapical bone destruction in dog's teeth.

The aim of this study was to determine the influence of periapical radiographs, cone beam computed tomography (CBCT) sections, and cone beam volumetric data on the determination of periapical bone destruction in endodontically treated distal root canals of premolar canine teeth. Nontreated mesial roots were used as controls. Enterococcus faecalis strain (ATCC 29212) was inoculated into 30 root canals of 2 mongrel dogs to induce apical periodontitis. After 60 days, the root canals of the distal roots of the 11 mandibular and 4 maxillary premolars were endodontically treated (n = 15). The mesial root canals were used as controls (no treatment). The bone destruction was evaluated after 6 months by 5 evaluators using periapical radiographs and by CBCT (coronal and sagittal sections). After the experimental period, the area of the lesions in periapical radiographs and CBCT sections were measured in mm(2) using the ImageTool software. A single evaluator measured the volumetric data using the OsiriX software. The comparison between the diagnosis methods in treated root canals and controls was performed using parametric and nonparametric criteria. The Pearson correlation coefficient was computed between radiographic values and CBCT volumetric data in treated root canals and controls. The results showed the presence of chronic apical periodontitis in every inoculated tooth. After 6 months, periapical radiographs, coronal CBCT sections, and volumetric data showed lower bone destruction in endodontically treated teeth in comparison with the control group (P < .05). The 5 evaluators found no differences between the apical periodontitis area of treated teeth and controls when CBCT sagittal sections were used (P > .05). No correlation was found between x-ray and CBCT volumetric values in treated root canals. Although selected CBCT sagittal sections showed similar values of bone destruction in endodontically and nontreated root canals, volumetric CBCT data showed that periapical lesions of endodontically treated root canals had half of the volume of periapical lesions in nontreated root canals. No relationship could be found between the periapical values of bone destruction and volumetric data found in CBCT of treated rood canals.

被引量：16 发表：1970

Tumor-infiltrating lymphocytes, particularly the balance between CD8(+) T cells and CCR4(+) regulatory T cells, affect the survival of patients with oral squamous cell carcinoma.

The objective of this study was to clarify the prognostic significance of tumor-infiltrating lymphocytes (TILs) in oral squamous cell carcinoma (OSCC); the present study analyzed various TIL-related parameters. Immunohistochemistry was performed in 87 patients with OSCC for the following TIL-related parameters: nest-CD8(+) T cells, stromal CD8(+) T cells, CD4(+) T cells, total regulatory T cells (Tregs), CCR4(+) Tregs, ratio of nest CD8(+) T cells/CCR4(+) Tregs, and ratio of stromal CD8(+) T cells/CCR4(+) Tregs. In univariate analyses, the following parameters were associated with decreased survival: few nest- and stromal CD8(+) T cells and more stromal CCR4(+) Tregs, but not total Tregs. Low ratios of nest and stromal CD8(+) T cell/CCR4(+) Treg were associated with worse survival. In multivariate analysis, the stromal CD8(+) T cell/CCR4(+) Treg ratio was an independent prognostic factor. Host immune responses in the stroma of OSCC affect the survival of the patients. The in situ balance between effector T cells and regulatory T cells is the most important factor predicting survival.

被引量：67 发表：1970

A biomechanical analysis of titanium miniplates used for treatment of mandibular symphyseal fractures with the finite element method.

This study aimed to evaluate the stress distribution and stress shielding effect of titanium miniplates used for the treatment of symphyseal fractures using finite element (FE) analysis. Two 3-D FE models of symphyseal fractured mandibles reduced by technique 1, reduction with a single miniplate, and technique 2, reduction with 2 miniplates, respectively, were developed. Three basic loading conditions were simulated. The ratios of stress shielding of miniplates were different. Ratios of the lower miniplates in technique 2 were much higher than the upper miniplates and the miniplates in technique 1 during all conditions, and that value of the lower miniplate gained a maximum value of 83.34% during left unilateral molar clenching. The stress areas were concentrated on the central section of the miniplates. However, the stress distribution varied with masticatory conditions. The study demonstrated that miniplate stress distribution and stress shielding effect ratio were affected not only by the way in which the mandible was loaded but also by the number of the miniplates fixing the fracture.

被引量：6 发表：2010

Management of a patient with a taurodont, single-rooted molars associated with multiple dental anomalies: a spiral computerized tomography evaluation.

被引量：7 发表：2009