Medically compromised children and adults are increasingly likely to seek orthodontic care as improved medical management creates more long-term survivors. Orthodontic treatment is often considered to be completely noninvasive procedure but if orthodontic treatment is to benefit a medically compromised patient, the advantages it offers should outweigh any possible damage it may cause. It is important to assess the risks of treatment as well as the potential gain and balance these aspects of treatment before deciding to render treatment of a malocclusion in medically compromised cases because some patients may be at risk for serious sequelae. Health care professionals and Orthodontist must give appropriate knowledge of oral health care and likelihood effect on oral biology in medical conditions is also essential. The practitioner should be alert to side effects of drug treatment such as xerostomia and depressed immune response, and be aware of the particular features of the underlying disease. Bleeding disorders, which can be managed by replacement of missing clotting factors, do not contraindicate orthognathic surgery. This book covers each aspect of sytemic disease in orthodontics