Background: Diabetic mellitus type ? is a metabolic disorder of diverse etiological factors, characterized by hyperglycemia resulting from an absolute deficiency of insulin affected childhood and adolescent. Some of these patients seek an orthodontic care .The orthodontist who is treating these medically compromised patients should have a working knowledge of the multitude of medically complex problems. This information will support and enable for delivery of high standards of dental care in general and orthodontic care in particular. The aim of this study was to analyze serum IgG levels and salivary secretory IgA (sIgA) levels in human dentine extract (HDE) before (T0) and 6 months after (T6) orthodontic treatment and to correlate anti-HDE autoantibodies to root resorption in well-controlled type ? diabetic patients. Materials and methods: Sixty individuals, who were attending to Al-Mustansiriya National Diabetes Center from April to October, 2012 and classified as well- controlled type ? diabetic patients (HbA1c <8.5), were participating in this study .The mean age of the whole samples was (15±1 SD ) years, thirty three of them(18 males and 15 females) were not wearing orthodontic appliance and were selected as the controls, while twenty seven of them (12 males and 15 females) were wearing orthodontic appliance . Periapical radiographs of the upper central incisors , unstimulated saliva and serum samples were obtained of all patients before(T0) and 6 months after(T6) orthodontic treatment. Anti-dentine antibody (Ab) levels were determined by mean of enzyme linked immune sorbant assay (ELISA) technique. At T6, root resorption was classified as grade 0 (no resorption), grade 1 (slight resorption), and grade 2 (moderate to severe resorption). Chi square test and T- test were used to assess the association between qualitative and quantitative results respectively ,while paired t- test was used to analyze the results before(T0) and 6 months after(T6) orthodontic treatment. Differences were considered significant at P<0.05. Results: There was statistical significant difference in the level of (anti- dentine Ab) in saliva between the two study groups at T0 and T6, its level was higher in the wearing group comparing with non wearing group, while it didn’t differ in serum. In the wearing group, the level of anti -dentine antibody in serum and saliva significantly decreased at T6 comparing with its level at T0. High level of the (anti -dentin Ab) shown in serum and saliva in grade 1 root resorption (R1) comparing with grade 0 root resorption (R0) at T0 and also at T6. Conclusions: The results of this study indicate that the anti -dentin antibody plays an important role in the detection of root resorption during orthodontic treatment in well- controlled diabetic patients type ? and its level is different according to the grade of root resorption in both saliva and serum.