Effectiveness of appliance therapy in reducing overjet and open bite associated with thumb sucking habit.

AIM: The aim of this paper was to compare the effectiveness of appliance therapy and reward therapy in reducing overjet and open bite associated with thumb sucking habit. METHODS: Thirty nine subjects (17 males and 22 females) with chronic thumb sucking habit were allocated to three groups: group A (positive reinforcement), group B (modified triple loop corrector), and group C (control). Pre-treatment and post-treatment study casts were evaluated for changes in overjet and open bite. Data from measurements of the three groups were statistically analyzed using a non-parametric Kruskal-Wallis test and Mann-Whitney U tests. All statistical computation was performed with SPSS 15.0 software. Significance was set at 0.05 level. RESULTS: Statistically significant reductions in mean overjet and open bite were seen for the group treated with appliance therapy when compared to other two groups (P<0.05). CONCLUSION: Appliance therapy was significantly more superior in reducing the overjet and open bite associated with thumb sucking habit. Early interception of these habits is recommended to reduce the incidence of malocclusion in children.

Macromolecular intravenous contrast agent for MR lymphography: characterization and efficacy studies.

PURPOSE: To determine the pharmacokinetic and magnetic resonance (MR) imaging properties of diethylenetriaminepentaacetic acid (DTPA) conjugated with a polyglucose-associated macrocomplex (PGM), which accumulates in lymph nodes. MATERIALS AND METHODS: In 124 normal and 20 tumor-bearing rats, Gd-DTPA PGM was administered intravenously in doses of 2, 10, 20 mumol gadolinium per kilogram of tissue. RESULTS: Mean blood half-life was 2 hours. Maximum accumulation in peripheral (33.0% injected dose [ID]/g +/- 16.2 [standard deviation]) and central lymph nodes (63.2% ID/g +/- 16.5) was observed within 24 hours after administration. The optimum dose range was 10-20 mumol Gd/kg in rats. At 24 hours after administration of 20 mumol Gd/kg, the signal-to-noise ratio increased from 30.9 +/- 0.4 to 83.2 +/- 5.2 in normal lymph nodes (P < .001). Differentiation between normal and metastatic lymph nodes was improved. CONCLUSION: When labeled with Gd-DTPA, the PGM-based graft copolymer significantly increases signal intensity at MR imaging of normal but not metastatic lymph nodes without causing distortion artifacts.

MR lymphography with a lymphotropic T1-type MR contrast agent: Gd-DTPA-PGM.

A model system of a paramagnetic lymphotropic MR contrast agent (Gd-DTPA labeled polyglucose associated macrocomplex, PGM) for T1-weighted MR imaging of lymph nodes in rats and rabbits was evaluated. Pharmacokinetic (tissue accumulation) and MR imaging data (optimal dose and timing parameters) were obtained in normal rats (n = 88) after subcutaneous (SC) injection of paramagnetic, radiolabeled [111In]Gd-DTPA-PGM. A rabbit model of lymph node metastases (n = 8) was ultimately used to demonstrate the potential of MR imaging with Gd-DTPA-PGM for nodal tumor detection. Maximum concentrations of Gd-DTPA-PGM were found in popliteal and paraaortic lymph nodes within 24 h after SC administration, and highest lymph node SNR values were obtained by MR imaging at this time point. The optimum imaging dose was 6-12 mumol Gd/kg. Tumor-lymph node contrast increased from 0.0 +/- 1.2 precontrast to 19.2 +/- 6.5 (spoiled gradient echo sequence, TR 50/TE 7/flip angle 60 degrees) postcontrast and conspicuity of nodal metastases was improved. Gd-DTPA-PGM accumulates in lymph nodes after SC administration and significantly enhances lymph node signal intensity of normal animals but not metastatic lymph nodes.