Evaluation of the effect of apical lesion on mucosal thickening and thickness of apical bone using limited cone-beam computed tomography.

OBJECTIVE: The purpose of this study was to evaluate the effect of periapical lesion size on the degree of mucosal thickening of maxillary sinus and thickness of apical bone using cone-beam computed tomography. MATERIALS AND METHODS: In Group 1 (teeth with apical lesions), diameter of apical lesion, width of apical bone, thickness of Schneiderian membrane; for Group 2 (teeth without apical lesions), width of apical bone in long axis of root and thickness of Schneiderian membrane were measured on coronal and sagittal images. RESULTS: Mann-Whitney U-test revealed no significant difference between two groups regarding mucosal thickening and apical bone measurements (P > 0.05). Wilcoxon signed-rank test showed no significant difference between the measurements in sagittal and coronal slices (P > 0.05). CONCLUSION: Results of the present study showed that Schneiderian membrane near the maxillary premolars and molars with apical lesions is not significantly thicker compared to teeth without apical lesions.

Perception of anatomical structures in digitally filtered and conventional panoramic radiographs: a clinical evaluation.

OBJECTIVES: The aims of the study were to compare subjective image quality of clinical images obtained with a storage phosphor plate (SPP)-based digital and conventional film-based panoramic system for the visualization of various anatomical structures and to evaluate the effect of various processing algorithms on image interpretation. METHODS: Panoramic radiographs were taken in 42 patients both with film and with a SPP system. SPP images were treated with shadow, sharpen, negative, greyscale sigma and greyscale exponential filters. Four observers subjectively evaluated films and unfiltered and filtered SPP images for the visibility of anatomical structures with various radiodensities as well as for overall image quality on a three-point rating scale. The statistical methods used were Kruskal-Wallis, odds ratio analysis and Cohen's kappa. RESULTS: No statistically significant difference was found between film and unfiltered digital images except for low-contrast structures (P > 0.05). Film images were preferred for the visibility of low-contrast structures (P < 0.05). Best overall image quality was obtained with sharpened images (P < 0.05) followed by films and unfiltered digital images. Among all filtered images, sharpened ones received the highest ratings for the visibility of all anatomical structures (P < 0.05). The intra- and interobserver agreement ranged between moderate and substantial and between fair and moderate, respectively. CONCLUSIONS: Film and unfiltered SPP-based panoramic images performed equally well in terms of overall quality; however, films were best for the perception of low-contrast structures. The sharpening filter may be recommended for enhancing SPP panoramic images to improve the visual perception of most of the anatomical structures as well as overall quality.

Perceptibility curve test for digital radiographs before and after application of various image processing algorithms.

OBJECTIVES: The aim of the present study was to compare digital radiographs before and after the application of various digital image enhancement methods by means of a perceptibility curve (PC) test. METHODS: Radiographs of an aluminium test object containing holes with sizes ranging from 0.5 mm to 1.5 mm were exposed at nine time settings, ranging from 0.05 s to 3.2 s using Digora (Soredex, Helsinki, Finland) storage phosphor system. Original digital images were then enhanced and displayed in colour-coded, contrast- and brightness-enhanced, histogram-equalized and negative modes. Thus, five series of images were created. Eight observers independently evaluated all of the images in the same random order and under the same viewing conditions. The object detail with the lowest perceptible contrast was recorded for each observer and each image type. Modified PCs were plotted according to the mean observer data. Repeated-measures ANOVA was used to compare the PCs and the perceptible number of details in original and enhanced images for each exposure (P=0.05). The Bonferroni/Dunn test was used to identify statistical differences among the groups. RESULTS: Histogram equalization showed the maximum number of perceptible details in both the lowest optimal exposure time and the widest exposure range (P<0.05). Significant differences were present in low and middle exposure ranges of images enhanced with various modalities (P<0.05), while no difference was obtained among the number of details for different enhancements in the high exposure range (P>0.05). CONCLUSION: Histogram-equalization enhancement of Digora images demonstrated subjectively superior image quality, followed by contrast and brightness enhancement.

Facial subcutaneous calcinosis and mandibular resorption in systemic sclerosis: a case report.

Systemic sclerosis (SSc) is an autoimmune disease characterized by widespread fibrosis of subcutaneous connective tissue, causing serious complications with the involvement of other systems. Tight, firm skin is the main characteristic of SSc, causing extrinsic pressure and the obliteration of the vessels. This then leads to ischaemia and destruction of the underlying bone. This mechanism may also lead to bone resorption of the mandibular body as it affects other bones of the skeleton. To date, only two cases of reported calcinosis in the facial area have been observed. In this report, a rare case of SSc with both subcutaneous calcinosis and mandibular bone resorption is presented. The role of dental practitioners in the diagnosis of the disease with respect to the orofacial symptoms is also discussed.

Complete replacement resorption after replantation of maxillary incisors: report of case.

This article describes the treatment of a 17-year-old patient with complete root resorption of the maxillary permanent central and lateral incisors following avulsion and replantation seven years ago. The most important factor influencing the prognosis of replanted teeth is the status of the periodontal ligament (PDL). As a result of replantation, the PDL cells necrosed and tooth replacement resorption occurred. The main factors, which affected the resorption after replantation and survival of PDL cells, could be summarize as; dry extraoral time greater than 30 minutes, the kept tooth in a dry environment, touching the cementum surface, and splint treatment for a prolonged time. Since complete root resorption was found in our case, these factors probably also occurred.