de Souza Júnior Joane Augusto, Garcia Renata Cunha Matheus Rodrigues, Moura Juliana Silva, Del Bel Cury Altair Antoninha
Department of Dentistry, State University of Ponta Grossa (UEPG), Brazil.
J Appl Oral Sci. 2006 Jun;14(3):208-12. doi: 10.1590/s1678-77572006000300012.
Although visible light-polymerized acrylic resins have been used in removable partial dentures, it is not clear whether the presence of a metal framework could interfere with their polymerization, by possibly reflecting the light and affecting important properties, such as roughness and hardness, which would consequently increase biofilm accumulation. The aim of this study was to compare the roughness and Knoop hardness of a visible light-polymerized acrylic resin and to compare these values to those of water-bath- and microwave-polymerized resins, in the presence of a metal framework. Thirty-six specimens measuring 30.0 x 4.0 +/- 0.5 mm of a microwave- (Onda Cryl), a visible light- (Triad) and a water-bath-polymerized (Clássico) (control) acrylic resins containing a cobalt-chromium metal bar were prepared. After processing, specimens were ground with 360 to 1000-grit abrasive papers in a polishing machine, followed by polishing with cloths and 1-microm diamond particle suspension. Roughness was evaluated using a profilometer (Surfcorder SE 1700) and Knoop hardness (Kg/mm(2)) was assayed using a microhardness tester (Shimadzu HMV 2000) at distances of 50, 100, 200, 400 and 800 microm from the metal bar. Roughness and Knoop hardness means were submitted to two-way ANOVA and compared by Tukey and Kruskal Wallis tests at a 5% significance level Statistically significant differences were found (p<0.05) for roughness and Knoop hardness, with light-polymerized resin presenting the highest values (Ra = 0.11 microm and hardness between 20.2 and 21.4 Kg/mm(2)). Knoop values at different distances from the metal bar did not differ statistically (p>0.05). Within the limitations of this in vitro study, it was concluded that the presence of metal did not influence roughness and hardness values of any of the tested acrylic resins.
尽管可见光聚合丙烯酸树脂已用于可摘局部义齿，但尚不清楚金属支架的存在是否会干扰其聚合，因为金属可能会反射光线并影响诸如粗糙度和硬度等重要性能，进而增加生物膜的积聚。本研究的目的是在有金属支架的情况下，比较可见光聚合丙烯酸树脂的粗糙度和努氏硬度，并将这些值与水浴聚合和微波聚合树脂的值进行比较。制备了36个尺寸为30.0×4.0±0.5mm的样本，分别为含钴铬金属棒的微波聚合（Onda Cryl）、可见光聚合（Triad）和水浴聚合（Clássico，对照）丙烯酸树脂。加工后，样本在抛光机中用360至1000目砂纸打磨，然后用布和1微米金刚石颗粒悬浮液抛光。使用轮廓仪（Surfcorder SE 1700）评估粗糙度，并使用显微硬度计（Shimadzu HMV 2000）在距金属棒50、100、200、400和800微米处测定努氏硬度（Kg/mm²）。粗糙度和努氏硬度平均值进行双向方差分析，并通过Tukey和Kruskal Wallis检验在5%显著性水平下进行比较。结果发现，粗糙度和努氏硬度存在统计学显著差异（p<0.05），可见光聚合树脂的值最高（Ra = 0.11微米，硬度在20.2至21.4 Kg/mm²之间）。距金属棒不同距离处的努氏值无统计学差异（p>0.05）。在本体外研究的局限性内，得出的结论是，金属的存在不会影响任何测试丙烯酸树脂的粗糙度和硬度值。
