Void detection in root fillings using intraoral analogue, intraoral digital and cone beam CT images

AIM

To compare void detection in root fillings using different radiographic imaging techniques: intraoral analogue, intraoral digital and cone beam CT (CBCT) images and to assess factors influencing small void detection.

METHODOLOGY

Two straight root canals in canine teeth were prepared. Calibrated steel wires of five different diameters (200, 300, 350, 500, 800 microm) were inserted respectively in the canal after the injection of a sealer. To simulate filling voids of known dimensions, the wires were removed after the sealer had set. Each sample was imaged, using a Minray X-ray tube (Soredex, Helsinki, Finland) at optimal clinical settings combined with Vistascan PSP (Dürr Dental, Bietigheim-Bissingen, Germany), Digora Optime PSP (Soredex), Sigma CCD (Instrumentarium, Tuusula, Finland) and E-speed films (Agfa-Gevaert, Mortsel, Belgium). The teeth were also imaged using CBCT (3D Accuitomo, Morita, Japan). A generalized mixed model and ANOVA analysis were used on the acquired data (Tukey-Kramer correction).

RESULTS

There was no evidence that the factor 'root level' affected void detection in root fillings. 'Void size' was a main determining factor as all voids larger than 300 microm were determined with all techniques. For the smaller voids, there were significant differences between the 5 imaging techniques at different void sizes and different root levels.

CONCLUSIONS

Void size and imaging technique were main determining factors. Voids larger than 300 mum were determined with all imaging techniques. For small void detection, all digital intraoral techniques performed better than intraoral analogue and CBCT images.

Laboratory aid in the diagnosis of acute appendicitis. A blinded, prospective trial concerning diagnostic value of leukocyte count, neutrophil differential count, and C-reactive protein

The diagnostic value of C-reactive protein (CRP), total white blood cell (WBC) count, total neutrophil count, and neutrophil differential count were evaluated in a prospective blinded study of 204 patients submitted with the tentative diagnosis of acute appendicitis. The laboratory tests were performed on blood samples obtained at the time of admission, and the results were stored until the patients were discharged. One hundred patients were operated on: 59 had appendicitis, 3 had other surgically correctable diseases, and 38 had a superfluous exploration. All 104 nonoperated patients recovered spontaneously. The sensitivity, specificity, and predictive values of single tests and test combinations were calculated at different cutoff levels. Using standard reference intervals, WBC count demonstrated the best sensitivity (83 percent) and predictive value of a negative result (88 percent). Combining the tests by an "or" rule enhanced the sensitivity to 100 percent, employing WBC count or CRP or neutrophil percentage above the reference range (triple test), but at the expense of the predictive value of a positive test (37 percent). It was concluded that both single tests and combined tests are of limited value in predicting acute appendicitis. However, the same triple test combination proved a predictive value of a negative result at 100 percent (95 percent confidence limits 92 to 100 percent), indicating that acute appendicitis is unlikely when these tests are simultaneously negative. The triple test combination was valid in 32 percent of the patients who were free from appendicitis. In the study group, 10 of the patients (25 percent) who had a superfluous exploration had a negative triple test, and they might have avoided surgery if it had been used. Therefore, the triple test is recommended as a help in reducing the significant rate of negative laparotomies in patients suspected of having acute appendicitis.

Rhesus immunization after Rh-incompatible kidney transplantation

Rh-immunization of a male recipient was observed following the transplantation of two kidneys from Rh-pos donors. Immunosuppression consisted of azathioprine, prednisone and antilymphocyte globulin (1st transplantation) and cyclosporin A and prednisone (2nd transplantation). The immunization was probably caused by the residual blood in the cadaver kidneys. The use of cyclosporin A might increase the risk of Rh-immunization.