Simplified cementation of lithium disilicate crowns: Retention with various adhesive resin cement combinations.

STATEMENT OF PROBLEM: A composite resin cement and matching self-etch adhesive was developed to simplify the dependable retention of lithium disilicate crowns. The efficacy of this new system is unknown. PURPOSE: The purpose of this in vitro study was to determine whether lithium disilicate crowns cemented with a new composite resin and adhesive system and 2 other popular systems provide clinically acceptable crown retention after long-term aging with monthly thermocycling. MATERIAL AND METHODS: Extracted human molars were prepared with a flat occlusal surface, 20-degree convergence, and 4 mm axial length. The axio-occlusal line angle was slightly rounded. The preparation surface area was determined by optical scanning and the analysis of the standard tessellation language (STL) files. The specimens were distributed into 3 cement groups (n=12) to obtain equal mean surface areas. Lithium disilicate crowns (IPS e.max Press) were fabricated for each preparation, etched with 9.5% hydrofluoric acid for 15 seconds, and cleaned. Cement systems were RelyX Ultimate with Scotch Bond Universal (3M Dental Products); Monobond S, Multilink Automix with Multilink Primer A and B (Ivoclar Vivadent AG); and NX3 Nexus with OptiBond XTR (Kerr Corp). Each adhesive provided self-etching of the dentin. Before cementation, the prepared specimens were stored in 35°C water. A force of 196 N was used to cement the crowns, and the specimens were polymerized in a 35°C oven at 100% humidity. After 24 hours of storage at 100% humidity, the cemented crowns were thermocycled (5°C to 55°C) for 5000 cycles each month for 6 months. The crowns were removed axially at 0.5 mm/min. The removal force was recorded and the dislodgement stress calculated using the preparation surface area. The type of cement failure was recorded, and the data were analyzed by 1-way ANOVA and the chi-square test (α=.05) after the equality of variances had been assessed with the Levene test. RESULTS: The Levene test was nonsignificant (P=.936). The ANOVA revealed the mean removal stresses, and forces did not differ for RelyX Ultimate with Scotchbond Universal (3.9 MPa; 522 N) and Multilink Automix with Multilink Primer (3.7 MPa; 511 N); both differed significantly (P=.022) from the mean for NX3 Nexus with OptiBond XTR (2.9 MPa; 387 N). For all 3 cements, the modes of failure showed cement principally on the crown intaglio, and the chi-square analysis was nonsignificant (P=.601). CONCLUSIONS: IPS e.max Press (lithium disilicate) crowns were well retained (2.9-3.9 MPa; 387-522 N) by the 3 cement-adhesive combinations after 6 months of aging with monthly thermocycling. These results can serve as a basis for cement selection for this type of crown because the values significantly exceeded those for zinc phosphate. Cements using their matched dentin bonding agent as the ceramic primer were as successful as cements with a separate silane coupling agent.

Standardized anthropometric evaluation of ectropion repair results.

BACKGROUND: Before undergoing ectropion repair, most patients are concerned not only about the functional result, but also about their postoperative aesthetic appearance. Furthermore, there is an ongoing discussion in the literature about the influence of various surgical techniques on eyelid function and morphology. We present a photograph-assisted evaluation for preoperative planning, intraoperative estimation, and postoperative evaluation of ectropion surgery based on anthropometric measurements and clinical data. PATIENTS AND METHODS: From January 2008 to December 2010, 36 ectropion patients underwent a lateral tarsorrhaphy or fascial sling repair. An analysis of standardized preoperative and postoperative photographs included measurements of intercanthal width, biocular width, eye fissure width, eye fissure height, lid sulcus height, upper lid height, upper iris coverage, lower iris coverage, position of cornea to palpebra inferior, canthal tilt, scleral show, and ectropion. RESULTS: Eye fissure index (P < 0.01) and lower iris coverage (P < 0.01) were statistically significantly influenced by surgery and time. The rates of scleral show (P < 0.01) and ectropion (P < 0.01) were significantly influenced, too. The 2 applied surgical techniques, lateral tarsorrhaphy and fascial sling repair, presented no significantly different effect in the preoperative to postoperative measurements. CONCLUSIONS: In all analyzed patients, the performed measurements were reproducible and reliable. The methods described may help to estimate the necessary extent of correction in ectropion repair surgery. Furthermore, intraoperatively performed measurements could be compared with the postoperative results.

Dual-energy CT virtual noncalcium technique: detecting posttraumatic bone marrow lesions--feasibility study.

PURPOSE: To evaluate traumatized bone marrow with a dual-energy (DE) computed tomographic (CT) virtual noncalcium technique. MATERIALS AND METHODS: In this prospective institutional review board-approved study, 21 patients with an acute knee trauma underwent DE CT and magnetic resonance (MR) imaging. A software application was used to virtually subtract calcium from the images. Presence of fractures was noted, and presence of bone bruise was rated on a four-point scale for six femoral and tibial regions by two radiologists. CT numbers were obtained in the same regions. Consensus reading of independently read MR images served as the reference standard. Image ratings and CT numbers were subjected to receiver operating characteristic curve analysis. RESULTS: After exclusion of 16 regions owing to artifacts, MR imaging revealed 59 bone bruises in the remaining 236 regions (19 of 114 femoral, 40 of 122 tibial). Fractures were present in eight patients. Visual rating revealed areas under the curve of 0.886 and 0.897 in the femur and 0.974 and 0.953 in the tibia for observers 1 and 2, respectively. For CT numbers, the respective areas under the curve were 0.922 and 0.974. If scores of 1 and 2 (strong or mild bone bruise) were counted as positive, sensitivities were 86.4% and 86.4% and specificities were 94.4% and 95.5% for observers 1 and 2, respectively. The kappa statistic demonstrated good to excellent agreement (femur, kappa = 0.78; tibia, kappa = 0.87). CONCLUSION: This DE CT virtual noncalcium technique can subtract calcium from cancellous bone, allowing bone marrow assessment and potentially making posttraumatic bone bruises of the knee detectable with CT.

Impact of FDG PET for staging of Ewing sarcomas and primitive neuroectodermal tumours.

AIM: High-grade Ewing sarcomas and Primitive neuroectodermal tumours (PNET) make up the tumours of the Ewing family. Our purpose was to evaluate the value of [18F]fluorodeoxyglucose positron emission tomography (FDG PET) in patients with Ewing tumours. PATIENTS AND METHODS: Twenty-four patients who had PET because of a suspected Ewing tumour during a 5-year period were included in this retrospective study. The images of 33 whole-body FDG PET investigations performed in primary or secondary diagnostics were analysed visually and semi-quantitatively by using standardized uptake values (SUVs). In 14 cases, PET was compared to bone scintigraphy regarding bone lesions. The final diagnosis was based on histology, imaging and follow-up. RESULTS: Histologically, the primary lesions were 10 Ewing sarcoma, 13 PNET and one osteomyelitis. The sensitivity and specificity of an examination-based analysis (presence of Ewing tumour and/or its metastases) were 96 and 78%, respectively. Altogether, 163 focal lesions were evaluated. Sensitivity and specificity regarding individual lesions were 73 and 78%. This lower sensitivity is mainly due to small lesions. In true-positive cases, the mean SUV was 4.54+/-2.79, and the SUVs in two false-positive cases were 4.66 and 1.60. True-positive and false-positive cases could not be differentiated definitively based on SUVs because of overlap and low values in true-positive lesions. In four cases, PET depicted 70 while bone scintigraphy depicted only eight bone metastases. CONCLUSION: An FDG PET investigation is a valuable method in the case of Ewing tumours. PET is superior to bone scintigraphy in the detection of bone metastases of Ewing tumours. For the depiction of small lesions, mainly represented by pulmonary metastases, PET is less sensitive than helical computed tomography. Determination of the role of whole-body FDG PET in diagnostic algorithm needs further investigation.

Detectability of liver metastases in malignant melanoma: prospective comparison of magnetic resonance imaging and positron emission tomography.

PURPOSE: We evaluated the diagnostic accuracy of magnetic resonance imaging (MRI) and positron emission tomography (PET) for detection of liver metastases in malignant melanoma. MATERIAL AND METHODS: Thirty-five patients with 39 combined unenhanced MRI and fluorine-18 deoxyglucose (F-18 FDG) PET scans were prospectively studied. In discordant imaging findings final diagnosis was proven by clinical follow-up >6 months and demonstration of progressive liver metastases by at least one imaging method. Sensitivities and specificities were compared and the influence of lesion size and melanin content on diagnostic accuracy was determined. RESULTS: MRI and PET were concordantly negative for presence and number of liver metastases in 28 patients and positive in four patients. PET and MRI were false positive in one patient each. In one patient MRI showed a single metastases not seen by PET and in one patient MRI demonstrated more metastases at the first examination. In follow-up investigations MRI revealed more metastases than PET in both patients. The sensitivities for lesion detection were 47% (16/34) for PET and 100% for MRI. Lesion detectability by PET was related to lesion size (P < 0.0001) but not to melanin content. CONCLUSION: MRI is more sensitive in the detection of liver metastases in patients with malignant melanoma. Small lesions are easily missed by PET, while melanin content does not influence detectability by PET.

Intensification of therapeutic approaches reduces mortality in diabetic patients with acute myocardial infarction: the Munich registry.

OBJECTIVE: The myocardial infarction (MI) registry of the Academic Schwabing Hospital, Munich, investigates the hospital course of diabetic and nondiabetic patients with acute MI. The aim of this study was to improve quality care management and to compare hospital mortality and therapeutic approaches (i.e., PTCA, stenting, GPIIb/IIIa receptor antagonists, glucose-insulin infusion). RESEARCH DESIGN AND METHODS: Data of diabetic patients and nondiabetic patients were analyzed. All diabetic and nondiabetic subjects who were admitted in 1999 and 2001 were included: 1999, 126 (38%) diabetic and 204 (62%) nondiabetic patients; 2001, 91 (31%) diabetic and 205 (59%) nondiabetic patients. RESULTS: In 1999, coronary angiography (P < 0.01), percutaneous transluminal coronary angioplasty (PTCA) (P < 0.001), and stenting (P < 0.001) were performed less frequently in diabetic than in nondiabetic patients. During this period, total hospital mortality (29 vs. 16%, P < 0.01) and mortality within 24 h after admission (14 vs. 5%, P = 0.01) were higher in diabetic than in nondiabetic patients. In 2001, frequencies of coronary angiography, PTCA, and stenting were increased in diabetic patients (P < 0.001 vs. 1999), and the interventions were comparable with those performed in nondiabetic patients. Furthermore, glucose-insulin infusion was administered in 46% of diabetic subjects. In 2001, total hospital mortality decreased to 17% in diabetic subjects (P = 0.028 vs. 1999) and mortality within 24 h after admission declined to 4% (P = 0.027 vs. 1999). Logistic regression analysis revealed that an increase in the number of therapeutic approaches (also when adjusted for clinical variables) is associated with a reduction in mortality of diabetic patients with acute MI (adjusted odds ratio 0.14, P < 0.0001). CONCLUSIONS: Intensification of multiple advanced therapeutic strategies in diabetic patients with acute MI enables a substantial reduction in hospital mortality. The enforcement leads to rates of hospital mortality that are comparable to those of nondiabetic patients.

Comparative diagnostic value and therapeutic relevance of magnetic resonance imaging and bone marrow scintigraphy in patients with metastatic solid tumors of the axial skeleton.

PURPOSE: To evaluate the comparative impact of magnetic resonance imaging (MRI) and bone marrow scintigraphy (BMS) in bone marrow metastases of solid tumors. METHODS: In 20 patients with solid tumors MRI of the axial skeleton and whole-body BMS were retrospectively reviewed. Detectability of metastases, extent of disease and therapeutic implications were assessed. RESULTS: In 15/20 (75%) patients MRI and BMS concordantly revealed bone marrow metastases of the axial skeleton. In nine of these 15 patients (60%) MRI showed more metastases. Local radiotherapy or surgery was performed in seven of these cases (78%). BMS detected additional metastases of the appendicular skeleton in 8/15 (53%) patients. In 4/20 cases (20%) the imaging findings were discordant. In three patients with degenerative changes (n=2) or lipoma (n=1) BMS was false positive. In another patient BMS failed to detect metastases proven by MRI and clinical follow-up resulting in subsequent radiation therapy. One patient had normal bone marrow. CONCLUSION: MRI appears to be more sensitive and specific in the detection of bone marrow metastases in the axial skeleton and is of clinical importance for subsequent local therapy.

Objective anthropometric analysis of eyelid reconstruction procedures.

Before undergoing facial tumour resection and reconstruction, especially of the eyelids, patients are worried about their postoperative appearance. "Eye-balling" of postoperative results may not be sufficient to adequately judge surgical results. Reference anthropometric measurements for the eyelids are available. We present an evaluation of a series of tumour resection and reconstructive procedures of the eyelids on standardized photographs based on reference anthropometric data. 51 patients underwent eyelid reconstruction with different established techniques after resection of local eyelid tumours. Analysis included intercanthal width, biocular width, eye fissure width, eye fissure height, lid sulcus height, upper lid height, upper iris coverage, lower iris coverage, position of cornea to palpebra inferior, scleral show, ectropion, and canthal tilt. We clearly differentiated between resections including eyelid margin or not. Time (p = 0.04) and surgery (p = 0.03) showed a significant association with decreased values of lower eyelid coverage. Resection of the eyelid margin showed no significant influence on the values investigated. In all the patients analysed the indices were reproducible and reliable. Not surprisingly an association between surgery and lower eyelid retraction was found. Resection of the eyelid margin does not seem to cause a greater risk of eyelid deformity. The standard measurements described are accurate and objective to evaluate postoperative results.

Can homogeneous preparation encoding (HoPE) help reduce scan time in abdominal MRI? A clinical evaluation.

PURPOSE: To evaluate time efficiency, image quality, and diagnostic value of a clinical routine homogeneous preparation encoding (HoPE) imaging protocol in different malign and inflammatory abdominal conditions. MATERIALS AND METHODS: A total of 14 healthy volunteers and 40 patients were examined after written informed consent and approval of the local ethics committee. A standard abdominal T1-weighted (T1W) fat-saturated gradient-echo protocol was compared to the HoPE sequence protocol ensuring for comparable imaging parameters. Examinations were performed on a 1.5-T Siemens Avanto equipped with a multichannel body-array coil. Image analysis was performed with respect to contrast-to-noise ratio (CNR) and signal-to-noise ratio (SNR), level of fat suppression (FS), generation of artifacts, and overall image quality by two blinded radiologists. RESULTS: In addition to comparable results in overall image quality and FS level, the HoPE sequence protocol provided a reduction in acquisition time of up to 40%. In addition, artifact generation was same or even reduced with respect to pulsation. Quantitative SNR analysis showed strong correlation between HoPE and the conventional method. CONCLUSION: The HoPE technique is a feasible and time-saving alternative for clinical abdominal MRI. Future studies will have to be conducted on larger patient collectives to strengthen the impact of this promising technique for FS imaging and to prove its accuracy.

Detection of prion particles in samples of BSE and scrapie by fluorescence correlation spectroscopy without proteinase K digestion.

A characteristic feature of prion diseases such as bovine spongiform encephalopathy (BSE) is the accumulation of a pathological isoform of the host-encoded prion protein, PrP. In contrast to its cellular isoform PrP(C), the pathological isoform PrP(Sc) forms insoluble aggregates. All commercial BSE tests currently used for routine testing are based on the proteinase K (PK) resistance of PrP, but not all pathological PrP is PK-resistant. In the present study, single prion particles were counted by fluorescence correlation spectroscopy (FCS). The property of PK resistance is not required, i.e., both the PK-resistant and the PK-sensitive parts of the prion particles are detectable. PrP aggregates were prepared from the brains of BSE-infected cattle, as well as from scrapie-infected hamsters, by the NaPTA precipitation method without PK digestion. They were labeled using two different PrP-specific antibodies for FCS measurements in the dual-color mode (2D-FIDA). Within the limited number of samples tested, BSE-infected cattle and scrapie-infected hamsters in the clinical stage of the disease could be distinguished with 100% specificity from a control group. Thus, a diagnostic tool for BSE detection with complete avoidance of PK treatment is presented, which should have particular advantages for testing animals in the preclinical stage.

Radiological findings in Boerhaave's syndrome.

The aim was to define the diagnostic value of chest radiography, esophagography, and computed tomography (CT) in patients with Boerhaave's syndrome. CT findings in 14 patients (11 male, 3 female; mean age: 60 years; median age: 66 years; age range: 36-78 years) with spontaneous esophageal perforation were retrospectively reviewed and compared to those of esophagography ( n=11) and chest radiography ( n=14). In six patients unenhanced CT scans were available; in ten patients (2/10 patients had an unenhanced CT before) a contrast-enhanced CT was performed as an emergency investigation. In 5/14 patients additional oral contrast medium was given. Chest radiography revealed pleural effusions in 9/14 and infiltrates in 9/14 patients. Pneumothorax and pneumopericardium were observed in two patients each. Pneumomediastinum was seen in three patients. Two chest radiographs were normal. Esophagography performed in 11 patients demonstrated contrast medium extravasation at a supradiaphragmatic level in seven patients, indicating esophageal perforation with esophagopleural fistula, and a submucosal contrast medium collection in four cases. Unenhanced CT scans revealed four intramural hematomas with typical localization. Unenhanced and contrast-enhanced CT demonstrated periesophageal air collections indicating esophageal perforation in all patients. Pleural effusions were seen in 11/14 and infiltrates in 8/14 patients. Contrast medium extravasation was observed in 5/14 patients, whereas a thickening of the esophageal wall was depicted in 11/14 patients. Periaortic air tracks ( n=7), pneumothorax ( n=3), pneumomediastinum ( n=6), and mediastinal fluid collections ( n=7) were depicted in CT. By demonstrating periesophageal air tracks suggestive of esophageal perforation, CT reveals the decisive criteria for diagnosing Boerhaave's syndrome and should therefore be performed in the diagnostic work-up of patients in whom this syndrome is part of the differential diagnosis.

Computed tomography in gastrointestinal stromal tumors.

The aim of this study was to define the imaging characteristics of primary and recurrent gastrointestinal stromal tumors (GIST) in computed tomography with respect to the tumor size. Computed tomography was performed in 35 patients with histologically confirmed gastrointestinal stromal tumors and analyzed retrospectively by two experienced and independent radiologist. The following morphologic tumor characteristics of primary ( n=20) and ( n=16) recurrent tumors were evaluated according to tumor size, shape, homogeneity, density compared with liver, contrast enhancement, presence of calcifications, ulcerations, fistula or distant metastases and the anatomical relationship to the intestinal wall, and the infiltration of adjacent visceral organs. Small GIST (<5 cm) showed a sharp tumor margin with homogeneous density and structure on unenhanced and contrast-enhanced images, and were characterized by an intraluminal tumor growth. Intermediate sized GIST (>5-10 cm) demonstrated an irregular shape, inhomogeneous density on unenhanced and contrast-enhanced images, a combined intra- and extraluminal tumor growth with aggressive findings, and infiltration of adjacent organs in 9 primary diagnosed and 2 recurrent tumors. Large GIST (>10 cm), which were observed in 8 primary tumors and 11 recurrent tumors, showed an irregular margin with inhomogeneous density and aggressive findings, and were characterized by signs of malignancy such as distant and peritoneal metastases. Small recurrent tumors had a similar appearance as compared with large primary tumors. Computed tomography gives additional information with respect to the relationship of gastrointestinal stromal tumor to the gastrointestinal wall and surrounding organs, and it detects distant metastasis. Primary and recurrent GIST demonstrate characteristic CT imaging features which are related to tumor size. Aggressive findings and signs of malignancy are found in larger tumors and in recurrent disease. Computed tomography is useful in detection and characterization of primary and recurrent tumors with regard to tumor growth pattern, tumor size, and varied appearances of gastrointestinal stromal tumors, and indirectly gives hints regarding dignity and therefore prognostic outcome.