Pulpal sequelae after trauma to anterior teeth among adult Nigerian dental patients

<p>Abstract</p> <p>Background</p> <p>Epidemiological studies show that about 11.6% to 33.0% of all boys and about 3.6% to 19.3% of all girls suffer dental trauma of varying severity before the age of 12 years. Moderate injuries to the periodontium such as concussion and subluxation are usually associated with relatively minor symptoms and hence may go unnoticed by the patient or the dentist, if consulted. Patients with these kinds of injuries present years after a traumatic accident most of the time with a single discoloured tooth. This study sets out to document the incidence of various posttraumatic sequelae of discoloured anterior teeth among adult Nigerian dental patients.</p> <p>Methods</p> <p>One hundred and sixty eight (168) traumatized discoloured anterior teeth in 165 patients were studied. Teeth with root canal treatment were excluded from the study. Partial obliteration was recorded when the pulp chamber or root canal was not discernible or reduced in size on radiographs, total obliteration was recorded when pulp chamber and root canal were not discernible. A retrospective diagnosis of concussion was made from patient's history of trauma to the tooth without abnormal loosening, while subluxation was made from patient's history of trauma to the tooth with abnormal loosening.</p> <p>Results</p> <p>Of the 168 traumatized discoloured anterior teeth, 47.6% and 31.6% had partial and total obliteration of the pulp canal spaces respectively, 20.8% had pulpal necrosis. Concussion and subluxation injuries resulted more in obliteration of the pulp canal space, while fracture of the teeth resulted in more pulpal necrosis (p < 0.001). Injuries sustained during the 1^stand 2^nddecade of life resulted more in obliteration of the pulp canal space, while injuries sustained in the 3^rddecade resulted in more pulpal necrosis.</p> <p>Conclusion</p> <p>Calcific metamorphosis developed more in teeth with concussion and subluxation injuries. Pulpal necrosis occurred more often in traumatized teeth including fractures.</p

Neighbor Overlap Is Enriched in the Yeast Interaction Network: Analysis and Implications

The yeast protein-protein interaction network has been shown to have distinct topological features such as a scale free degree distribution and a high level of clustering. Here we analyze an additional feature which is called Neighbor Overlap. This feature reflects the number of shared neighbors between a pair of proteins. We show that Neighbor Overlap is enriched in the yeast protein-protein interaction network compared with control networks carefully designed to match the characteristics of the yeast network in terms of degree distribution and clustering coefficient. Our analysis also reveals that pairs of proteins with high Neighbor Overlap have higher sequence similarity, more similar GO annotations and stronger genetic interactions than pairs with low ones. Finally, we demonstrate that pairs of proteins with redundant functions tend to have high Neighbor Overlap. We suggest that a combination of three mechanisms is the basis for this feature: The abundance of protein complexes, selection for backup of function, and the need to allow functional variation

Management of Root Fractures

Horizontal root fractures are frequently occurring consequences of acute traumatic dental injury (TDI). They are described as fractures separating the root into coronal and apical segments, with the fracture lines being completely or partially confined within the bone. Depending on the degree of injury, different treatment regimens may be applied. However, because the overall prevalence of root fracture is low, health‐care professionals are often insecure regarding appropriate management. In general, root fracture treatment aims to preserve the functional integrity and aesthetics of the teeth involved. Treatment failure may eventually lead to tooth loss, with potentially negative lifetime consequences, such as impaired orofacial development. Altogether, it is indispensable for the health‐care professional to know the biological foundation, diagnostic approaches and appropriate treatment modalities for root‐fractured teeth. This chapter provides information on all these aspects, as well as the currently recommended recall regime and expected outcomes

Experimental studies of SPECT scintimammography with combined cone-beam and parallel-beam collimators

Conventional SPECT Tc-99m sestamibi scintimammography (STSM) has limited clinical utility due to fairly low radiopharmaceutical uptake in the breast tissue as compared to the heart and the liver. We investigated the use of a cone-beam collimator (CBC) to STSM. Each detector on a multi-headed gamma camera can be equipped with parallel-beam (PBC) or cone-beam collimators (CBC). PBC can provide truncation-free SPECT projection sets, while CBC offers increased sensitivity in a limited field-of-view (FOV). Combined PBC and CBC SPECT data acquisition may provide improved lesion contrast and overall better imaging performance within CBC FOV with significantly reduced truncation artifacts in the reconstructed images. In this paper we evaluate the combined CBC&PBC SPECT method using a limited number of confirmed breast cancer patients and female chest phantoms with simulated breast lesions. We envision the combined CBC&PBC SPECT as a useful clinical tool in scintimammography

Application of Ordered-Subsets Expectation- Maximization (OSEM) algorithm to cone-beam SPECT for accelerated 3D reconstruction

We investigated the performance of an ordered-subsets expectation- maximization (OSEM) algorithm for accelerated reconstruction in cone-beam SPECT. SPECT scans were performed using a Defrise phantom filled with 0.9 μCi/ml of Tc-99m and a dual-head gamma camera equipped with one cone-beam (CBC, f = 70 cm) and one parallel-beam collimator (PBC). Images were reconstructed using a fully-3D approach with resolution and attenuation modeling and an ordered-subsets version of a maximum-likelihood expectation-maximization algorithm (MLEM). Three grouping patterns of subsets were applied: consecutive, orthogonal, and uniform. In contrast to PBC SPECT, we observe that, in CBC SPECT, the reconstruction grouping pattern of the subsets is very important for the image quality obtained. Only when the projection data grouped into a subset were selected as uniformly as possible from all the acquired views, were the image quality and the noise in the images very close to results obtained using MLEM. However, we note that, for both CBC and PBC SPECT, the loglikelihood for a given iteration is practically the same for different grouping patterns of subsets. © 2004 IEEE

Theoretical studies on optimization of tomographic performance of cone-beam collimator for SPECT scintimammography

The major component limiting SPECT performance is the gamma camera collimator. Typical parallel-hole collimator has low sensitivity yielding noisy tomographic projection images for clinically useful imaging times and radiation dose to the patients. The problem of high noise and low count density is especially acute in scintimammography due to relatively low uptake in the breast tissue, as compared to the heart and the liver. A practical solution for improved SPECT camera performance in scintimammography might be application of cone-beam collimator (CBC). It offers increased sensitivity in a limited field-of-view (FOV). Disadvantages of CBC include limited and spatially variable FOV, generation of truncation artifacts outside FOV, and more difficult truly 3D reconstruction. In this paper, we investigate some theoretical aspects of optimization of CBC for applications in SPECT scintimammography