[A case report of giant cemento-ossifying fibroma].

Cemento-ossifying fibroma is a rare benign tumor from periodontium, which usually occurs in mandible body and mandible ramus. It consists of collagen fibrils, fibroblast, and cementoblast. This article reported a case of giant cemento-ossifying fibroma and discussed the clinical features and treatment.

Pyrazine-diium bis-(3-carb-oxy-4-hydroxy-benzene-sulfonate) dihydrate.

Pyrazine and 5-sulfosalicylic acid crystallize from a methanol solution containing water as the title salt, C(4)H(6)N(2) (2+)·2C(7)H(5)O(6)S(-)·2H(2)O. The pyrazine-diium cation sits on an inversion center. The component ions and water mol-ecules are linked by inter-molecular O-H⋯O, N-H⋯O and C-H⋯O hydrogen bonds into layers running parallel to the (10) plane.