Comparative Evaluation of Colour Stability and Surface Hardness of Methacrylate Based Flowable and Packable Composite -In vitro Study
Dr. Nandini Thipannanavar Niranjan,
Govindam Karyavattom, po-695581, Trivandrum, Kerala, India.
Introduction: With the advent of new technology in material sciences in recent years, the quality of composite resin restorations has improved; however, discolouration and wear of composite resin materials remains to be a major problem in long-term clinical studies.
Aim: The aim of the present study was to compare the colour stability and surface hardness of methacrylate based flowable nano composite with methacrylate based packable nano composite.
Materials and Methods: The difference in colour stability and microhardness of the three composites: G aenial Universal Flo (GC India), Filtek Z350XT (3MESPE) and Tetric N Ceram (Ivoclar Vivadent) were evaluated. Forty eight disc shaped specimens were made out of three different resin composite materials which were subdivided into two groups of Colour Stability (CS) and Vickers Hardness (VH). For colour stability, specimens were immersed in staining solution consisting instant coffee for 72 hours, and then specimens were rinsed thoroughly under tap water and subjected to 10 strokes of brushing with a soft-grade toothbrush. The colour measurements were obtained using spectrophotometer and the process was repeated every 72 hours for three weeks. VH was evaluated using microhardness tester (Zwick/Roell Vickers Microhardness Tester). Vickers Hardness Numbers (VHN) were determined from indentations made under 10 N load for 15 seconds by the arithmetic mean of three indentation values randomly performed. One-way ANOVA and Tukeyâ€™s post-hoc analysis were applied.
Results: Statistically significant difference was found in comparison of colour stability at different time interval in study groups (p<0.001). Filtek Z350XT group showed least discolouration followed by Tetric N Ceram group and highest colour change in G aenial Universal Flo group after immersion for 21 days. Mean microhardness value of Filtek Z350XT (101.62) group was found to be significantly different from Tetric N Ceram group (63.74) (p<0.001*) and G aenial Universal Flo group (56.75) (p<0.001*).
Conclusion: Greatest CS and VH was seen in Filtek Z350XT followed by Tetric N Ceram and least values were seen in G aenial Universal Flo.