Inflammatory process of the gingival tissues and/or periodontal membrane of the teeth, resulting in an abnormally deep gingival sulcus, possibly producing periodontal pockets and loss of supporting alveolar bone.
(source: ADA Council on Scientific Affairs).The noble metal classification system has been adopted as a more precise method of reporting various alloys used in dentistry. The alloys are defined on the basis of the percentage of metal content and listed in order of biocompatibility.