Chandu G S, Asnani Pooja, Gupta Siddarth, Faisal Khan Mohd
Professor and Head, Department of Prosthodontics, RishiRaj College of Dental Sciences and Research Centre, Bhopal, Madhya Pradesh, India.
Post-graduate Student, Department of Prosthodontics, RishiRaj College of Dental Sciences and Research Centre, Bhopal, Madhya Pradesh, India.
J Int Oral Health. 2015 Apr;7(4):63-8.
Use of alkaline peroxide denture cleanser with different temperature of water could cause a change in surface hardness of the acrylic denture and also has a bleaching effect. The purpose of the study was to determine the effect of increased water content during thermal cycling of hot water-treated acrylic on the surface hardness of acrylic denture base when compared to warm water treated acrylic. And to compare the bleaching effect of alkaline peroxide solution on the acrylic denture base on hot water and warm water treated acrylic.
Forty samples (10 mm × 10 mm × 2.5 mm) were prepared. After the calculation of the initial hardness 40 samples, each was randomly assigned to two groups. Group A: 20 samples were immersed in 250 ml of warm distilled water at 40°C with alkaline peroxide tablet. Group B: 20 samples were immersed in 250 ml of hot distilled water at 100°C with alkaline peroxide tablet. The surface hardness of each test sample was obtained using the digital hardness testing machine recording the Rockwell hardness number before the beginning of the soaking cycles and after completion of 30 soak cycles and compared. Values were analyzed using paired t-test. Five samples from the Group A and five samples from Group B were put side by side and photographed using a Nikon D 40 digital SLR Camera and the photographs were examined visually to assess the change in color.
Acrylic samples immersed in hot water showed a statistically significant decrease of 5.8% in surface hardness. And those immersed in warm water showed a statistically insignificant increase of 0.67% in surface hardness. Samples from the two groups showed clinically insignificant difference in color when compared to each other on examination of the photographs.
Thermocycling of the acrylic resin at different water bath temperature at 40°C and 100°C showed significant changes in the surface hardness.
使用不同水温的碱性过氧化物假牙清洁剂会导致丙烯酸假牙表面硬度发生变化，并且具有漂白作用。本研究的目的是确定与温水处理的丙烯酸相比，热水处理的丙烯酸在热循环过程中含水量增加对丙烯酸假牙基托表面硬度的影响。并比较碱性过氧化物溶液对热水和温水处理的丙烯酸假牙基托的漂白效果。
制备40个样本（10毫米×10毫米×2.5毫米）。在计算40个样本的初始硬度后，将每个样本随机分为两组。A组：20个样本与碱性过氧化物片剂一起浸泡在250毫升40°C的温蒸馏水中。B组：20个样本与碱性过氧化物片剂一起浸泡在250毫升100°C的热蒸馏水中。使用数字硬度测试机在浸泡周期开始前和30个浸泡周期完成后记录洛氏硬度值，从而获得每个测试样本的表面硬度，并进行比较。使用配对t检验分析数据。将A组的5个样本和B组的5个样本并排放置，用尼康D 40数码单反相机拍照，通过肉眼检查照片来评估颜色变化。
浸泡在热水中的丙烯酸样本表面硬度在统计学上显著下降了5.8%。而浸泡在温水中的样本表面硬度在统计学上有不显著的0.67%的增加。在检查照片时，两组样本之间在临床上颜色差异不显著。
丙烯酸树脂在40°C和100°C不同水浴温度下的热循环显示出表面硬度有显著变化。
