Scanning electron microscopy and profilometer evaluation of glazed and polished dental porcelain.

The surface roughness of Vita VMK porcelain following oven glazing and eight grinding/polishing treatments was analyzed qualitatively using scanning electron microscopy and quantitatively using a profilometer. Techniques were selected to simulate clinical practice. Scanning electron microscopy evaluation found oven glazing produced a better surface than other polishing methods. On the basis of the profilometric examination, the best roughness average value was obtained using diamond instruments with progressively smaller particle sizes (30, 15, and 8 microns). Scanning electron microscopy analysis showed that all the treatments left the surfaces partially porous and cracked; however, the glazed surface yielded the best result. Although no significant differences were detected for the different treatments, the use of a 30-microns diamond instrument produced a rougher surface. No correlation was found between scanning electron microscopy and profilometer results. This study suggests that several procedures may be used to effectively finish ceramic surfaces.

Granular cell ameloblastoma. An immunocytochemical study.

Granular cell ameloblastoma is characterized by nests of large, eosinophilic granular cells. These latter have long been the subject of debate. Two cases of granular cell ameloblastomas have been immunocytochemically stained with a panel of antibodies against human mitochondria, S-100 protein, CD 68, low molecular weight cytokeratins, chromogranin, laminin, vimentin, PCNA, bcl-2 and p-53. Granular cells exhibited a membranous positivity with cytokeratins while the non granular cells of the same tumors showed a diffuse cytoplasmic reactivity. Moreover, granular cells showed marked cytoplasmic positivity with CD68 antiserum only while human mitochondria, as well as S-100 protein antisera, were consistently negative. PCNA, bcl-2 and p-53 did not stain the granular cells. These results allow easy distinction of granular cell ameloblastomas from similar tumors exhibiting granular cell changes and indicate that the granularity in ameloblastoma cells is consequent to lysosomal overload.

[The CO2 laser and endodontic surgery: an epicritical evaluation]. / Laser CO2 e chirurgia endodontica: valutazione epicritica.

The authors analyse the use of laser CO2 in endodontic surgery. They describe the laser biological effects on teeth, comprehending immediate structural changes (coagulation, carbonization, volatilization, fusion of dental tissue), and side effects (sterilization, modification of biomechanical properties and biostimulation). A surgical technique joining traditional aspects and laser radiation, restoring the apical shape to the anatomical origin is described. The employment of the laser in a defocalized way allows the sterilization of the apical region even in zones normally not reachable by the usual instruments. These devices are connected with laser irradiation and could improve the clinical results either improving bone restoration on raising dental tissue resistance to acidity. The authors emphasize that, whereas the clinical follow-up is in fact similar to the results obtained in a previous traditionally treated control group an accurate surgical technique will be the real important aspect to reach the recovery and the laser irradiation can help in it.

Proliferative response of human marginal gingiva to phlogistic process and titanium implant.

In order to detect proliferative processes in human marginal gingiva in pathological conditions and after externalization of titanium implants, we have attempted BrdU incorporation after "in vitro" incubation of tissue fragments. In comparison with healthy controls, immunocytochemical detection of samples from patients affected by hypertrophic gengivitis shows a good number of proliferating cells in the basal layer of the epithelium, while only in one case can positiveness be detected after externalization of titanium implants. Since after reduction of inflammation by hygienic treatment a low number of proliferating cells can be observed only in the regions where pathological alterations are also present, we suggest that the increase in tissue proliferation may be closely dependent on the intensity of the inflammatory process. All these data demonstrate that in vitro BrdU incubation of tissue fragments represents a suitable method to evaluate cell proliferation in human tissue.

[Control of the patency of porto-systemic anastomoses]. / Il controllo della pervietà delle anastomosi porto-sistemiche.

After having discussed the direct and indirect methods to control the patency of porto-systemic anastomoses, the Authors report on their series of 42 cases (28 side-to-side porto-cava shunts, 6 end-to-side porto-cava shunts, 6 spleno-renal shunts, 2 mesenterico-cava shunts) where the postop. control was carried out with portography, hepatic superselective arteriography in 29 cases, transcaval catheterism of the anastomosis in 6 patients, and pre-op., and post-op. echotomography in 15 cases. Portography revealed 39 cases of patent anastomosis and thrombotic occlusion in 3 cases. The typical sign of shunt patency is the visualisation of the inferior V.C. and the less frequent disappearance of right gastric reflux. Furthermore the investigations consented the evaluation of altered post-shunt hepato-portal flow: side-to-side porto-cava shunt (25 patent anastomoses) revealed a complete deviation of portal glow towards the I.V.C. and in 15 cases there was inverted portal flow; portography after splenorenal shunt (5 cases of patent anastomosis) showed a preserved hepatopetal portal flow only in early controls (7 days) while in all long term controls it was hepatofugal. In 13 cases the morphology of the hepatic arterial system was compared before and after surgery; in 12 cases the hepatic artery was larger and its intrahepatic branches more tortuous after surgery Ultrasonography revealed only 8 patent shunts out of 15 examined since the amount of gas in the bowel rendered the exam technically insufficient.

[Angiography in pre- and post-operative diagnosis of paediatric portal hypertension (author's transl)]. / L'angiografia nella diagnostica pre- e post-operatoria della ipertensione portale infantile: protocollo di impiego e semeiotica angiografica.

The authors report 31 cases of portal hypertension in childhood, including pre- and post-operative angiographic studies of 13 shunt operations. Preoperative angiography serve both to define the origin of the hypertension and to visualize compensatory collateral circulation. Postoperative angiography permits evaluation of the efficiency of the shunt, based on patency of anastomosis and reduction of collaterals, and has proved to be safe even when repeated or in emergency conditions.