اعلانات هامة

The objective of this research is to study the effect of re-heating of the thermosetting acrylic on the dimensional stability, surface hardness and bending resistance. Where the acrylic is usually used in biological environments and is often used in the mouth cavity in the form of oral complete devices caring missing teeth. The influence of these properties by re-heating reflects at the level of aches and pain caused by the use of this device in the patient's mouth. These factors were studied during the manufacture of a number of samples by heating polymerization, and then we measured the values of these properties after the initial curing process. The same properties were measured after re-heating and re-solidification of these samples. Statistical study, using the evaluation of the difference between the averages, was donning for showing of change in the values of those properties. The result shows that the only difference is statistically important for the dimensions were the largest one in the acrylic sample. And for the surface hardness the difference between the values, before and after the process of re-heating, was statistically significant. As well as, it has decreased significantly the resistance of bending. Therefore there was a significant impact on the material properties of the acrylic after the re-heating process, which can occur as a result of lining the device used. 

Key words: Acrylic, re-heating, dimensional stability, surface hardness, bending resistance.

الهدف من البحث هو دراسة تأثير اعادة تسخين ريزين الاكريليك المتصلب حراريا على ثبات الأبعاد والقساوة السطحية ومقاومة  الانحناء .حيث يستعمل الاكريليك عادة في الأوساط الحيوية وغالبا ما يستعمل في الحجرة الفموية على شكل أجهزة كاملة تحمل  الأسنان المفقودة .وينعكس تأثر هذه الخواص بإعادة التسخين على مستوى الألم الذي يحدثه استخدام هذا الجهاز في فم المريض .وتمت دراسة هذه العوامل من خلال تصنيع عدد من العينات  وتصليبها بالحرارة حيث تم قياس قيم هذه الخواص بعد عملية التصليب الأولي .بعد ذلك أجريت عملية اعادة التسخين لهذه العينات وتم قياس الخواص نفسها بعد التسخين واعادة التصليب .