البحث — المستودع الرقمي العراقي

المستخلص: New approaches for caries prevention by using lasers effect combined remineralizing agent providing calcium and phosphate in addition to flouride for increasing the tooth mineral resistance needed. The aim of this study is to evaluate a new treatment modality to decrease dental enamel dissolution via combing the effect of pulsed Nd : YAG laser (1064 nm) and MI plus paste (CPP - ACP containing sodium fluoride ) regarding the tooth pulp chamber temperature elevation, calcium concentration dissolute from enamel surfaces and the dental enamel absorption of methylene blue stain by assessing (R,G,B)values .Eighty human permanent premolar were used in this study, sixty of them were randomly divided into six groups of 10 specimens. The negative control group A received no treatment, and the positive control group B the MI plus paste was applied without laser irradiation. For the groups C, D, E and F the pulsed Nd : YAG (1064 nm) laser was used in two energy settings. The lower laser dose setting at (0.6W, 60 mJ )without and with the MI plus paste for the groups C and D respectively and the higher laser energy setting at (1.7W, 170 mJ )with and without the MI plus paste for the groups E and F respectively.Twenty teeth were used to asses s the temperature elevation during irradiation with laser using a K - type thermocouple at 37 ± 0.5 ̊C, ten teeth exposed to the lower laser energy settings and ten for the higher laser energy settings.A circular window (4 mm radius) marked area on buccal surfaces of the 60 samples after they had been coated with three layer of nail varnish to exposed to the Nd : YAG laser irradiation, and then the samples incubated in 3ml acidic solution of acetate buffer of (0.1M/L) with a pH value of 4.5 for 48 hours . The acidly etched samples removed from the acidic solution after they had been washed from acid they immersed in a 2% solution of methylene blue dye to measure the (R,G,B) values to indicted the affinity of sample surfaces for absorbing methylene blue stain that indicate the surface demineralization . Results of temperature test +showed that the maximum temperature increases for group E (4.7 Co) was very high significant difference (p<0.05) over that of groups C (2.5 Co).The atomic absorption photometry test results showed that groups C, and D were statistically different compared to the groups A and B (p<0.001) in the reduction of calcium dissolution, with a reduction percentage for groups C and D of 25.7% and 33.34% respectively compared to group A, with 21.75% and 29.8 % for groups C and D respectively in comparison to group B. While Groups E and F shown nonsignificant reduction in calcium dissolution compared to control groups.The (R,G,B)s value test showed that groups C and D having lower affinity to absorb methylene blue stain, and they are statically significant different compared to the groups A and B .while groups E and F showing a higher affinity to absorb methylene blue stain compared to control groups. In conclusion the both laser irradiation settings energy (60mJ, 0.6 W,0.12 J/cm2),(170mJ,1.7W,0.34J/cm2) are safe for the vitality of the dental pulp, and when both settings combined with the Phosphor - Peptide - Amorphous Calcium Phosphate with Fluoride ,the results showing significant reduction of dental enamel de - mineralization and lower affinity for methylene blue absorption that although indicate increasing dental enamel resistance to demineralization for the groups of (60mJ, 0.6 W,0.12 J/cm2) laser irradiation settings.

تاثير المعلمات المختلفة لليزر الليف على تعرية الصبغ البوليمري من على سطح سبيكة الالمنيوم نوع 5005A == Effect of Different Fiber Laser Parameters on Stripping of Polymer Paint from Surface of 5005A Aluminum Alloy

اسم المؤلف: هالة عبود جاسم

الموضوع العام: علوم الليزر

السنة: 2015

الموضوع الدقيق: تطبيقات الليزر في هندسة الميكانيك

الدرجة: ماجستير

الجامعة: جامعة بغداد - معهد الليزر للدراسات العليا

اللغة: الانكليزية

مكان الجامعة: بغداد

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