Comparison of surface gloss of resin composites according to changes in surface roughness

Abstract

Commonly used composite resin in clinical practice, has developed by improving aesthetics to obtain a smooth surface. However, the smooth surface of the restored composite resin becomes roughly over time. One of the primary methods for evaluating the surface of composite resin is gloss unit (GU). Gloss can be assessed visually and is easily recognized and perceived by both dentists and patients. Therefore, this study measured the gloss unit to evaluate the surface of several types of composite resins, and to evaluate the gloss retention rate of the composite resins, the roughened surface was observed compared to the control group. The specimens were produced of 5 composite resins, GRADIA DIRECT ANTERIOR(GA), Tetric N-Ceram (TN), Ceram.x sphereTEC one (CX), Filtek Z350 XT (FT), and ESTELITE ∑QUICK (ES). After creating a smooth surface with a slide glass, five locations were randomly selected to measure the surface gloss unit, and the average was set as the representative value for the specimen. After measuring the GU, roughness was given to the specimen under water pouring at the same speed (150rpm) and pressure(weight 252g) with SiC paper #2400, 1200, and 400. Each time the roughness was given with SiC paper, the GU was measured again. After applying roughness using the same SiC paper, GU between composite resins was compared. In addition, as SiC paper #2400, 1200, and 400 were used step by step, changes in the surface were evaluated, which became increasingly rougher than the surface made of slide glass. The statistical analysis method used was one-way analysis of variance and Tukey multiple comparisons test at the 95% confidence level. As a result of this study, there was a difference in GU between composite resins. When was the surface of the composite resin is made of slide glass, in the order of TN < GA < FT < ES < CX, when roughness was given to #2400, in the order of CX < TN < GA < ES < FT. When roughness was given to #1200, GU was higher in the order of CX < GA < TN < FT < ES, and when roughness was given to #400, in the order of FT < CX < GA < TN < ES (p<0.05). Each time SiC paper was used in rough stages, it gradually became rougher compared to the surface made of slide glass, and gloss retention rate was lowered. GA is 100% > 64.82% > 34.02% > 19.74%, TN is 100% > 64.53% > 48.56% > 28.74%, CX is 100% > 54.58% > 23.74% > 14.87%, FT is 100% > 94.53% > 55.37% > 14.76%, ES is 100% > 88.09% > 74.10% > 53.23% gloss retention rate has decreased (p<0.05). In conclusion, there was a difference in GU for each composite resin due to the characteristics of the composite resin. When compared to the control group, the gloss retention rate of the composite resins decreased after applying roughness in stages with SiC paper, but differed depending on the composite resins. Among composite resins, ES showed the best gloss retention rate. 임상에서 일반적으로 사용되는 복합레진은 매끄러운 표면을 얻기 위하여 심미성을 개선하며 발전해왔다. 하지만 수복된 복합레진의 매끄러운 표면은 시간의 흐름에 따라 구강내에서 마모되면서서 거칠게 변화한다. 복합레진의 표면을 평가하는 방법 중 하나는 표면 광택도이다. 광택도는 시각적으로 평가할 수 있고 치과의사와 환자 모두가 쉽게 인식하고 인지할 수 있다. 이에 본 연구는 수종의 복합레진의 표면을 평가하기 위하여 광택도를 측정하였고, control 그룹에 비하여 거칠게 변화하는 표면을 관찰하여 복합레진의 광택 유지도를 평가하고자 하였다. 복합레진 GRADIA DIRECT ANTERIOR (GA), Tetric N-Ceram (TN), Ceram.xsphereTEC one (CX), Filtek Z350XT (FT), ESTELITE ∑QUICK (ES) 5개를 이용하여 시편을 제작하였다. Slide glass로 매끄러운 표면을 만든 후 무작위로 5곳을 선정하여 표면 광택도를 측정하였고, 그 평균을 시편의 대표값으로 설정하였다. 광택도 측정 후 동일한 속도와 압력으로 주수 하에 SiC paper #2400, 1200, 400으로 거칠기를 주었고, SiC paper로 거칠기를 주었을 때 마다 광택도를 다시 측정하였다. 동일한 SiC paper를 이용하여 거칠기를 준 후 복합레진 간 GU를 비교하였다. 그리고 SiC paper #2400, 1200, 400을 단계별로 사용할수록 slide glass로 만든 표면보다 점점 거칠어지는 표면의 변화를 평가하였다. 통계분석을 위하여 one-way analysis of variance and Tukey multiple comparisons test를 이용하였다. 연구 결과, 복합레진 간 GU는 차이가 있었다. 복합레진의 표면을 slide glass로 만든 경우 TN < GA < FT < ES < CX순으로, #2400으로 거칠기를 준 경우 CX < TN < GA < ES < FT순으로, #1200으로 거칠기를 준 경우 CX < GA < TN < FT < ES순으로, #400으로 거칠기를 준 경우 FT < CX < GA < TN < ES순으로 GU가 높았다. 거친 단계별로 SiC paper를 사용할 때 마다 slide glass로 만든 표면에 비하여 점차 거칠게 변해서 gloss retention rate은 낮아졌다. GA의 gloss retention rate은 100% > 64.82% > 34.02% > 19.74%, TN은 100% > 64.53% > 48.56%> 28.74%, CX는 100% > 54.58% > 23.74% > 14.87%, FT는 100% > 94.53% > 55.37%> 14.76%, ES는 100% > 88.09% > 74.10% > 53.23%로 감소하였다 (p<0.05). 결과적으로 복합레진의 서로 다른 특성으로 인하여 복합레진 마다 GU에 차이가 있었다. 대조군과 비교 시 SiC paper를 이용하여 단계별로 거칠기를 준 후 복합레진의 gloss retention rate은 모두 감소하였으나 그 정도는 복합레진 별로 차이가 있었다. 그 중 가장 우수한 gloss retention rate을 보인 복합레진은 ES였다.