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Effects of preheating and artificial aging on radiopacity of different types of resin composites
Goktug Yersel1, Vildan Turgut2, Neslihan Tekce2
1Department of Restorative Dentistry, Faculty of Dentistry, University of Kocaeli, Kocaeli, Turkey, goktugyersel@gmail.com.
Purpose:
To investigate the changes in the radiopacity values of resin cements, resin composites, and flowable resin composites used for bonding after preheating.
Methods:
Three different materials (Panavia V5, Clearfil Majesty Posterior, and Clearfil Majesty Flow) were evaluated. For each material, five specimens with 0.5 mm and 1 mm thickness were prepared. Additionally, the two resin composites were preheated at 55°C and 68°C for 15 and 30 minutes, resulting in a total of 22 groups and 110 specimens. Periapical radiographs of the specimens were obtained. During radiograph acquisition, 0.5 mm and 1 mm human tooth sections, along with aluminum step wedges, were placed adjacent to the specimens. Mean Gray Value measurements were conducted using ImageJ software to determine aluminum equivalence. After 21 days at 37°C, the radiopacity values of the specimens were remeasured and compared with the initial values.
Results:
The radiopacity values of the 1 mm-thick specimens were significantly higher than those of the 0.5 mm-thick specimens (P= 0.001). Preheating the resin composites generally led to an increase in radiopacity. A Pearson correlation test was performed to assess the relationship between heating temperature and radiopacity, yielding a correlation coefficient of r= 0.249. This result indicates a weak but statistically significant correlation between temperature and radiopacity (P= 0.026). An increase in radiopacity values was observed with prolonged heating. Clearfil Majesty Posterior exhibited a steady increase in radiopacity with increasing heating time and temperature. However, Clearfil Majesty Flow showed a decrease in radiopacity values after prolonged heating at 68°C (P= 0.150). Following the artificial aging process, a statistically significant decrease in the radiopacity values of the samples was detected (P= 0.003).
Clinical Significance:
In recent years, preheating adhesive materials to enhance adhesion between different substrates has gained popularity. Preheating may also affect radiopacity values. Given the potential chemical changes induced by heat treatment, it is essential to evaluate heat-treated materials comprehensively across multiple parameters. Furthermore, the aging process can influence the radiopacity values of materials. Therefore, careful material selection is crucial for the long-term follow-up of restorations.
