異なるユニバーサルコンポジットの表面特性に対する胃酸の影響．SEMによる研究

The Effect of Gastric Acid on the Surface Properties of Different Universal Composites: A SEM Study.

抄録

本研究の目的は，3種の単色性（Omnichroma，Vittra Unique，Charisma Diamond One）および3種のユニバーサルシェード（Neo Spectra ST，Gænial A'CHORD，Nova Compo C）樹脂複合材料の模擬胃酸に暴露した後の表面粗さとマイクロ硬さの変化を比較することにある．各材料の評価用プレキシガラス型（= 5mm × = 2mm）を用いて，合計144枚の円板状試料（各コンポジットレジン24枚）を作製した．各材料の試験片は，微小硬さと表面粗さを評価するための2つのメイングループと，模擬胃酸に7日間および14日間暴露させるための2つのサブグループに分けられた．すべての試料の微小硬度と表面粗さを浸漬前に測定し（T1），その後，模擬胃酸に7日間（T2）および14日間（T3）曝露し，微小硬度と表面粗さの測定を繰り返した．各材料の各時間間隔（T1，T2，T3）で無作為に選んだ試料を走査型電子顕微鏡（SEM）で評価した。一元配置分散分析の結果，試験したすべてのコンポジットレジン修復材料の表面粗さおよび硬さは，初期値（T1）では統計的に有意な差は認められなかった（> 0.05）．7日目（T2）および14日目（T3）の表面粗さおよび微小硬さ値については，すべてのコンポジットレジンについて群間で統計的に有意な差が認められたが（＜0.05），表面硬さの減少率については時間間隔による統計的有意差は認められなかった（＞0.05）．本研究の結果，試験したユニバーサルコンポジット材料を模擬胃酸に暴露したときの表面粗さの増加および微小硬度の減少は，統計的に有意であった．

The aim of this study is to compare surface roughness and microhardness changes of three monochromatic (Omnichroma, Vittra Unique, and Charisma Diamond One) and three universal shade (Neo Spectra ST, Gænial A'CHORD, and Nova Compo C) resin composites after exposure to simulated gastric acid. A total of 144 disc-shaped specimens (24 discs of each composite resin) were prepared using plexiglass molds ( = 5 mm × = 2 mm) for evaluation from each material. Specimens of each material were divided into two main groups for the evaluation of the microhardness and surface roughness and also two subgroups for 7- and 14-day exposures to simulated gastric acid. Initial microhardness and surface roughness measurements of all samples were measured before immersion (T1) followed by exposing the samples to simulated gastric acid for 7 days (T2) and 14 days (T3), and then, the microhardness and roughness measurements were repeated. Randomly selected specimens of each material for each of the time intervals (T1, T2, and T3) were evaluated with scanning electron microscopy (SEM). One-way ANOVA revealed that the surface roughness and hardness values of all tested composite resin restorative materials show no statistically significant difference for the initial (T1) value ( > 0.05). Regarding the 7 day (T2) and 14 day (T3) surface roughness and microhardness value of all composites, there are statistically significant differences between the groups ( < 0.05), while there was no statistically significant difference between the surface hardness reduction percentage between the time intervals ( > 0.05). As a result of this study, increase in surface roughness and decrease in microhardness of the tested universal composite materials when exposed to simulated gastric acid were statistically significant.