The document discusses trauma from occlusion (TFO) in the periodontium. It defines TFO as injury to the periodontal tissues when occlusal forces exceed the tissues' adaptive capacity. TFO can be primary, from altered forces on normally supported teeth, or secondary, from normal/excessive forces on teeth with reduced support. The document reviews studies on the role of occlusion in periodontal disease and the stages of tissue response to increased forces. It provides guidance on clinical detection of TFO and treatment considerations like occlusal adjustment or splinting.