Treponema denticola is a gram-negative, obligate anaerobic, motile and highly proteolytic bacterium. The Gram-negative oral spirochete is associated with the incidence and severity of human periodontal disease. Treponema denticola levels in the mouth are elevated in patients with periodontal diseases and the species is considered one of the main etiological agents of periodontitis. 
T. denticola dwells in a complex and diverse microbial community in the oral cavity and is highly specialized to survive in this environment.
T. denticola is related to the syphilis-causing obligate human pathogen, Treponema pallidum subsp. pallidum.
Periodontal disease 
Periodontal disease is an infection and inflammation of the gingiva resulting in destruction of the surrounding tissues and alveolar bone. It occurs in 15% of adults at some time in their lives and can lead to bleeding on brushing, halitosis, tooth mobility and loss. Severe forms include aggressive periodontitis and necrotizing periodontitis which can cause rapid bone resorption and tooth loss along with ulceration of the gingiva and considerable pain.
Treatment involves removal of plaque and calculus on the root surfaces by scaling and root planing using various periodontal currettes. If the periodontal disease does not resolve, given at least 8–12 weeks for healing, the area is retreated. Periodontal surgery to raise a flap and root plane the affected teeth may be undertaken along with antibiotic therapy (systemic or local).
See also 
- Jobin M-C et al. (2008). "The Molecular Biology of the Survival and Virulence of Treponema denticola". Molecular Oral Microbiology. Caister Academic Press. ISBN 978-1-904455-24-0.