Thickness-Dependent Light Transmittance and Temperature Rise in Dual-Cure Bioactive and Light-Cure Bulk-Fill Composite Resins

Reema Alharbi; Eid Alharbi; Sanaa N Al-Haj Ali; Ra'fat I Farah

doi:10.3390/polym15132837

Thickness-Dependent Light Transmittance and Temperature Rise in Dual-Cure Bioactive and Light-Cure Bulk-Fill Composite Resins

Polymers (Basel). 2023 Jun 27;15(13):2837. doi: 10.3390/polym15132837.

Authors

Reema Alharbi¹, Eid Alharbi¹, Sanaa N Al-Haj Ali², Ra'fat I Farah³

Affiliations

¹ Dental Intern, College of Dentistry, Qassim University, Al Mulayda 51452, Qassim, Saudi Arabia.
² Department of Orthodontics and Pediatric Dentistry, College of Dentistry, Qassim University, Al Mulayda 51452, Qassim, Saudi Arabia.
³ Department of Prosthetic Dental Sciences, College of Dentistry, Qassim University, Al Mulayda 51452, Qassim, Saudi Arabia.

Abstract

This study aimed to assess the light transmittance (T) and temperature increase through different increments of dual-cure bioactive bulk-fill restorative material (ACTIVA), light-cure bulk-fill, and conventional composite resin materials. Cylindrical specimens with a diameter of 8 mm and heights of 1, 2, 3, and 4 mm of ACTIVA, Tetric-N-Ceram bulk-fill (TBF), Filtek One bulk-fill (FBF), and Filtek Z250 (FZ) (n = 6 per group, 96 in total) were light-cured with a visible blue low-intensity light-emitting diode (LED) (650-800 mW/cm² irradiance). T, and the temperature increase, were measured using an optical power meter and a digital thermometer during curing. The T mean values ranged between 0.012 and 0.239 (76.02 to 98.81% light attenuation), while the temperature rise mean values ranged between 9.02 and 20.80 °C. The parameters, including material type (partial eta squared (ηp²) = 0.284, p < 0.0001), thickness (ηp² = 0.284, p < 0.0001), and their interaction (ηp² = 0.185, p = 0.047), significantly affected the T values, whereas only the material type (ηp² = 0.352, p = 0.047) affected the temperature rise values. The T and temperature rise mean values were highest in ACTIVA increments of 1-mm increments, in particular, showing the highest T mean values, followed by similar increments of TBF. A significantly higher T was found in 1-mm increments compared to thicker increments for all materials (p < 0.0001), and a significant positive correlation existed between T and temperature rise values (r = 0.348, p = 0.001). These findings show that the bioactive material ACTIVA and TBF allow for better T than the other materials, with ACTIVA recording a higher temperature rise. However, the large light attenuation observed for all materials, irrespective of thickness, suggests that curing in more than one location with a low-intensity LED is necessary to optimize the curing process. Furthermore, incremental filling of bulk-fill materials using a low intensity LED could be beneficial.

Keywords: ACTIVA; bulk-fill; composite resin; dual-cure; extended curing; light; light-cure; temperature rise; thermocouples; transmittance.

Grants and funding

This research received no external funding.