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Objectives to make a reliable correlation between the chemical composition of the urinary calculi and its Hounsfield unit on CT scan, upon which we can depend on it for prediction of the type of the urinary calculi. The prediction of the chemical structure of the stone would help us to reach a more efficient therapeutic and prophylactic plan. Methods A retrospective study was performed by interpretation of the preoperative CT scans for patients who were presented by urinary stones. Identification of the chemical structure of the calculi was implemented using Fourier Transform Infrared Spectroscopy (FT-IR spectroscopy). The laboratory report revealed multiple types of stones either of pure or mixed composition. Afterwards, a comparison was done between Hounsfield units of the stones and the chemical structure. Results The chemical structure of the urinary stones revealed four pure types of stones (Uric acid, Calcium Oxalate, Struvite and Cystine) and two types of mixed stones (mixed calcium oxalate+ Uric, and mixed calcium oxalate+ calcium phosphate). Uric acid stone had a mean Hounsfield Unit (HU) density of428 ± 81, which was quite less than the other stones, followed by struvite stones with density ranging about 714 ± 38. Mixed calcium oxalate stones could be differentiated from other types of stones like uric acid, pure calcium oxalate and struvite stones by the Hounsfield unit of Computed Tomography (the mean Hounsfield Unit was 886 ± 139 and 1427 ± 152 for mixed calcium oxalate + uric stone and mixed calcium oxalate + calcium phosphate stones respectively). Moreover, pure calcium oxalate stones were easily differentiated from all other stones using the mean Hounsfield density as it was 1158 ± 83. It was challenging only when it was compared to cystine stones, as they were quiet similar to HU value (997 ± 14). The variation of Hounsfield values among the previously mentioned stones, was statistically significant (p < 0.001). Conclusion The study proved that the Hounsfield Unit of CT scanning is a convenient measure to predict the chemical structure of urinary calculi.

Objective: the aim of this study was to evaluate the efficiency of a new magnetic habit reminder in cessation of thumb sucking habit and correction of Anterior open bite. Material and Methods: This was a prospective clinical trial. The sample consisted of 20 subjects (7 boys and 13 girls) between the age of 5-12 years. Patients were eligible for this study if they had a thumb sucking habit with anterior open bite. Whereas the exclusion criteria included subjects with a history of previous orthodontic treatment, systemic diseases, and/or presence of any clefts. The appliance is a custom made fixed, removable appliance. It consists of two parts (intraoral and extraoral parts) enclosing two poles of gold coated neodymium and iron boron magnets. After insertion of the appliances, the participants were recalled every 4 weeks. At the end of the 6 th month of this study, the appliances were removed, and post-treatment records were taken. Results: PP/MP, FH/MP and LAFH/AFH showed significant reduction after treatment while PFH/AFH posttreatment significantly increased than pretreatment measurement. U1/PP, U1/SN, U1/NA(°) and U1/NA(mm) posttreatment measurements were significantly lower than pretreatment measurements. L1/MP, L1/NB (°), L1/NB(mm), UI/LI had no significant change after treatment. Nasolabial angle showed no significant change and the interlabial gap significantly reduced after treatment. Overjet was significantly reduced and overbite was significantly increased. Conclusion: The magnetic habit reminder was capable of stopping thumb sucking habit within the 6-month duration of the study with improvement of malocclusion associated with the habit.

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