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Purpose: There is insufficient data regarding the durability of porcelain laminate veneers bonded to existing composite fillings. The aim of the present study was to evaluate the fracture resistance and microleakage of porcelain laminate veneers bonded to teeth with existing composite fillings., Materials and Methods: Thirty maxillary central incisors were divided into three groups (for each group, n=10): intact teeth (NP), teeth with class III composite fillings (C3) and teeth with class IV cavities (C4). Porcelain laminate veneers were made using IPS-Empress ceramic and bonded with Panavia F2 resin cement. The microleakage of all of the specimens was tested before and after cyclic loading (1 × 10(6) cycles, 1.2 Hz). The fracture resistance values (N) were measured using a universal testing machine, and the mode of failure was also examined. The statistical analyses were performed using one-way ANOVA and Tukey post hoc tests (α=.05)., Results: There was a significant difference in the mean microleakage of group C4 compared with group NT (P=.013). There was no significant difference in the fracture loads among the groups., Conclusion: The microleakage and failure loads of porcelain laminate veneers bonded to intact teeth and teeth with standard class III composite fillings were not significantly different.

A 54 year old man was referred to us from his private physician for ventilation-perfusion lung scan. In both scans radiotracer activity was absent in the region of the right lung, while a prior chest X-rays film revealed no remarkable abnormality. Subsequent chest computed tomography revealed a hilar mass compressing the hilar vascular and bronchial area components. This case emphasizes that a hilar mass could induce both bronchial and vascular compression with end result matched ventilation-perfusion defect in the entire lung. The chest X-rays film was normal and the chest computed tomography showed a large hilar mediastinal mass. The differential diagnosis of this case is presented.