In order to depict occlusal contact area (OCA) within desirable occlusal clearance, the relationships between the luminosity of the image and the thickness of the impression material (IM) must be determined. These relationships under transmitted light (TL) are considered to conform Lambert's law, but those under reflected light (RL) will need to be modified. The purpose of this study was to confirm this hypothesis by comparing two absorption coefficient calculated from the functions and to verify the validity of the functions. Five materials with 30, um and 1 mm thickness of IM were photographed under TL on an inverter light box and under RL on a white dental stone plate. The luminosity of the images was measured using a personal computer with an application program. The mean (SD) absorption coefficient in the case of TL was 0.0081 (0.0009) and that in case of RL was 0.0084 (0.0008). These values were almost the same and the difference was not observed as tested by the paired t-test. Subsequently, the luminosity of the images of 15 materials with various thicknesses of IM within 200, um was measured with the same procedures and the adaptation of the functions were tested by ANOVA. The F-ratios were both highly significant (p <0.0001). Therefore, we conclude that these data support this hypothesis and the function describing the relationships between the luminosity and the thickness of IM contribute to depict OCA within desirable occlusal clearances.

View full abstract

A Glomus tumour is a benign neoplasm arising from the glomus cells which are located arteriovenous anastomosis in vascular plexus of skin and nail bed. In this paper, we report a case of glomus tumor arising in the palate and review of the literatures. A 21-year-old man presented with swelling measuring 3 cm in diameter in the hard and soft palate. Histopathological examination showed a well-circumscribed nodule formation in submucosa. Tumor cells were uniform shape and composed of solid proliferation with showed the pattern of nonepithelial neoplasm where the individual cells are surrounded by reteticulin fibers.
Immunohistochemical staining, vimentin, alpha smooth muscle actin and HHF-35 were positive and keratin, desmin, S-100 protein and factor VIII were negative in tumor cells. Our review of the literature revealed 24 reported cases of glomus tumor and appeared that a predilection of the palate (34.7%), male predominance (1.6 : 1) and slow growth.

View full abstract