Abouelmagd Dalia M, Basheer Rasha R
Restorative Dentistry Department, Faculty of Dentistry, King Abdulaziz University, Jeddah, Saudi Arabia and Cairo University, Cairo, Egypt.
Restorative Dentistry Department, Faculty of Dentistry, King Abdulaziz University, Jeddah, Saudi Arabia.
J Int Soc Prev Community Dent. 2022 Jun 29;12(3):353-359. doi: 10.4103/jispcd.JISPCD_66_22. eCollection 2022 May-Jun.
To investigate the effect of two acidic agents on microhardness of nanofilled and microhybrid resin composite materials.
70 resin composite discs (10 mm diameter and 2 mm thick) were prepared from 2 resin composites (35 from each type), nanofilled (Z350XT) and microhybrid (Z250), 3M/ESPE. Ten discs (5 from each group) were used as control (tested at 1 h before immersion). Each group was divided into 3 subgroups ( = 10) according to the storage media: distilled water (control), box-type cola and orange juice. Each subgroup was further subdivided into 2 divisions ( = 5) according to microhardness testing at 24 h and 7days after immersions. Digital Vickers Microhardness Tester (FM-7, Future Tech, Tokyo, Japan) was used to measure surface microhardness with a Vickers diamond indenter. The surface of the specimens received a load of 200 g for 10 seconds. Three indentations not less than 1 mm from each other were placed on the surface of all specimens. Vickers hardness number (VHN) was calculated for each indentation Data were statistically analyzed using one- way ANOVA followed by Newman-keuls tests ( ≤ 0.05).
Orange juice showed statistically significantly the lowest VHN mean value (92.7) followed by the Cola group (95.15) then the water group (104.02) compared to the control group (117.4). Microhybrid composite groups showed statistically significant higher VHN mean value (108.1) than the nanofilled composite (100.2). The 7days groups showed statistically significant lower VHN mean value (97.3) than 24h groups (106.6).
All storage media reduced hardness of resin composites with orange juice showing the highest reduction in hardness values. Microhybrid is more resistant to degradation than nanofilled composite. Over time, microhardness of resin composites decreased progressively.
研究两种酸性介质对纳米填充和微混合树脂复合材料显微硬度的影响。
用3M/ESPE的两种树脂复合材料（每种35个）制备70个树脂复合盘（直径10毫米，厚2毫米），分别为纳米填充型（Z350XT）和微混合型（Z250）。10个盘（每组5个）用作对照（在浸泡前1小时进行测试）。根据储存介质，每组分为3个亚组（n = 10）：蒸馏水（对照）、盒装可乐和橙汁。每个亚组根据浸泡后24小时和7天的显微硬度测试进一步细分为2个部分（n = 5）。使用数字维氏显微硬度计（FM - 7，日本东京未来技术公司），用维氏金刚石压头测量表面显微硬度。对试样表面施加200克载荷，持续10秒。在所有试样表面放置三个相互距离不小于1毫米的压痕。计算每个压痕的维氏硬度值（VHN）。数据采用单因素方差分析，随后进行纽曼 - 基尔斯检验（P≤0.05）进行统计分析。
与对照组（117.4）相比，橙汁组的VHN平均值在统计学上显著最低（92.7），其次是可乐组（95.15），然后是水组（104.02）。微混合复合组的VHN平均值（108.1）在统计学上显著高于纳米填充复合组（100.2）。7天组的VHN平均值（97.3）在统计学上显著低于24小时组（106.6）。
所有储存介质均降低了树脂复合材料的硬度，橙汁使硬度值降低最多。微混合型比纳米填充型复合材料更耐降解。随着时间的推移，树脂复合材料的显微硬度逐渐降低。
