PURPOSE: This in vitro study aimed to analyze and compare the reproducibility of zirconia and lithium disilicate crowns manufactured by digital workflow. MATERIALS AND METHODS: A typodont model with a prepped upper first molar was set in a phantom head, and a digital impression was obtained with a video intraoral scanner (CEREC Omnicam; Sirona GmbH), from which a single crown was designed and manufactured with CAD/CAM into a zirconia crown and lithium disilicate crown (n=12). Reproducibility of each crown was quantitatively retrieved by superimposing the digitized data of the crown in 3D inspection software, and differences were graphically mapped in color. Areas with large differences were analyzed with digital microscopy. Mean quadratic deviations (RMS) quantitatively obtained from each ceramic group were statistically analyzed with Student's t-test (α=.05). RESULTS: The RMS value of lithium disilicate crown was 29.2 (4.1) µm and 17.6 (5.5) µm on the outer and inner surfaces, respectively, whereas these values were 18.6 (2.0) µm and 20.6 (5.1) µm for the zirconia crown. Reproducibility of zirconia and lithium disilicate crowns had a statistically significant difference only on the outer surface (P<.001). The outer surface of lithium disilicate crown showed over-contouring on the buccal surface and under-contouring on the inner occlusal surface. The outer surface of zirconia crown showed both over- and under-contouring on the buccal surface, and the inner surface showed under-contouring in the marginal areas. CONCLUSION: Restoration manufacturing by digital workflow will enhance the reproducibility of zirconia single crowns more than that of lithium disilicate single crowns.
Ceramics* ; Crowns* ; Head ; In Vitro Techniques* ; Lithium ; Microscopy ; Molar*

Amyloidosis results from the deposition of insoluble, fibrous amyloid proteins, nearly always in the extracellular spaces of organs and tissues. There are several varieties of amyloidosis, each of which is identified by the immunochemical nature of amyloid protein fibrils. Amyloid goiter is a very rare clinical entity and can be confused with a neoplasm. We have experienced a case of amyloid goiter with hypothyroidism secondary to tuberculosis. A 20 years old women with 5 months history of pulmonary tuberculosis was admitted with complaints of diarrhea, abdominal pain, weight loss at one year ago. She had a non-tender, diffuse and firm goiter. Also she had normal thyroid function at the first admission but was found to be hypothyroid at the second admission, 10 months later. Histologic examination revealed amyloid deposition in thyroid gland, stomach, colon and rectum.
Abdominal Pain ; Amyloid* ; Amyloidogenic Proteins ; Amyloidosis ; Colon ; Diarrhea ; Extracellular Space ; Female ; Goiter* ; Humans ; Hypothyroidism* ; Plaque, Amyloid ; Rectum ; Stomach ; Thyroid Gland ; Tuberculosis ; Tuberculosis, Pulmonary ; Weight Loss ; Young Adult