Wear of lithium disilicate opposed by various ceramic materials.

OBJECTIVES: To compare volumetric wear of lithium disilicate against different ceramic (3 mol% yttria-stabilized (3Y) zirconia, 5 mol% yttria-stabilized (5Y) zirconia, lithium disilicate, porcelain and enamel antagonists). MATERIALS AND METHODS: Forty lithium disilicate (e.max CAD) specimens (n = 8/antagonist) were wet sanded to 1200grit SiC and mounted into a UAB wear device. Antagonist spheres (diameter = 4.75 mm) were made from polished 3Y zirconia, 5Y zirconia, lithium disilicate, porcelain and human enamel. A two-body wear test was performed with 20 N load and 1.5 mm slide for 400,000 cycles at 1 Hz. 33% glycerin was used as a lubricant. Wear facets were measured with optical profilometry. Wear scar areas of antagonists were measured with digital microscopy. Scanning electron microscopy was performed on wear facets and scars. Vicker's microhardness was measured of all antagonist materials. All data were compared with 1-way ANOVA and Tukey post-hoc analysis. RESULTS: Significant differences in lithium disilicate volumetric wear (mm3 ) occurred with various antagonist materials: 0.38 ± 0.01a (3Y zirconia), 0.33 ± 0.01b, (5Y zirconia), 0.16 ± 0.01c (lithium disilicate), 0.11 ± 0.03d, (enamel), and 0.07 ± 0.01e (porcelain). The lithium disilicate antagonist demonstrated a larger wear scar than other materials. Zirconia was the hardest material and enamel the least hard. CONCLUSIONS: Zirconia causes significant wear on lithium disilicate and lithium disilicate causes significant wear against itself. CLINICAL SIGNIFICANCE: When selecting a material to oppose an existing lithium disilicate crown, a porcelain or lithium disilicate surface would cause significantly less wear to the existing crown. If an existing zirconia crown exists opposed to a prepared tooth, lithium disilicate may not be an ideal material selection to restore the tooth.

Laparoscopic treatment of an unruptured cystic artery pseudo-aneurysm in the presence of calculous emphysematous cholecystitis.

Cystic artery pseudoaneurysm is a rare complication of invasive biliary procedures or of acute or chronic cholecystitis and pancreatitis. Emphysematous cholecystitis is an acute inflammatory process of the gallbladder due to gas forming organisms such as Escherichia coli and Clostridium perfringens. We report the case of a 34-year-old gentleman admitted with a 3-day history of generalized abdominal pain, vomiting and markedly raised inflammatory markers. A computed tomography scan demonstrated acute calculus cholecystitis and an incidental CAP. This was successfully treated with an emergency laparoscopic cholecystectomy. CAPs are reported in the literature as rare and are usually diagnosed after rupture with severe haemorrhage. In this report, we highlight that a non-ruptured CAP identified preoperatively can be safely managed simultaneously with a laparoscopic approach, thus avoiding the need for invasive angiographic procedures or open surgery.