habitation in the oral cavity is the gingival crevice. These spirochetes attach to proteins (including fibronectin and collagen) of local gingival fibroblasts, binding to their plasma membrane. A 53-kDa surface protein on T. denticola is responsible for transporting its components into the host cell, exhibiting a cytotoxic effect. Accumulation of T. denticola in this manner facilitates the disease-causing process, including membrane blebbing and red blood cell lysis. Role in disease Periodontal disease Periodontal disease is a type of gum disease caused by the accumulation of plaque on the teeth due to poor oral hygiene. Plaque is a sticky substance that contains bacteria which can harden into a substance called calculus, irritating the gums. Treponema denticola, a subgingival oral spirochete has been associated with many periodontal disease conditions such as: the early stage of periodontitis, acute pericoronitis (infection under the gum tissue covering a partially erupted tooth)3, as well as necrotising ulcerative gingivitis (severe inflammation of the gum more common in immunocompromised patients). It relates to lesions limited to gingival tissue. Clinical evidence and research shows that periodontal pockets contain large numbers of treponema denticola together with other proteolytic gram negative bacteria, playing an important role in the development of periodontal disease. The toxic products of these bacteria, especially treponema denticola may damage the surface lining periodontal cells making them more prone to damage as well as lysis. Treponema denticola attaches to fibroblasts and epithelial cells as well as to extracellular matrix components which are found in periodontal tissues and release its own bacterial contents. The bacterial components are: Outer sheath associated peptidases Chymotrypsin proteinases Trypsin proteinases Hemolytic activities Hemagglutinating activities outer-sheath protein with pore-forming properties A number of studies have observed an increase of T. denticola in patients with orthodontic appliances, particularly the fixed type. Oral cancer Treponema denticola is a potential etiological bacterial agent for oral cancer. It encourages oncogenesis (process in which healthy cells become cancer cells) and therefore the progression of oral cancer through chronic inflammation advancing invasiveness of the cancer cells. This results in the ceasing of cell apoptosis (inhibition of controlled cell death – a safety mechanism within cells to stop more damage from occurring), resulting in rapid growth and multiplication of cancer cells. This suppresses the immune system stopping the body from recognising the cancerous cells and as a result more cancer-promoting substances are produced. The presence of T. denticola along with other periodontal