Effect of Rapid High-Intensity Light-Curing on Increasing Transdentinal Temperature and Cell Viability: An In Vitro Study

• Published in: Polymers Vol. 16; no. 11; p. 1466
• Main Authors: Miranda, Samille Biasi, Lins, Rodrigo Barros Esteves, Santi, Marina Rodrigues, Denucci, Giovanna Corrêa, Silva, Cleyton Cézar Souto, da Silva, Silvana de Fátima Ferreira, Marques, Daniela de Araújo Viana, Montes, Marcos Antônio Japiassú Resende
• Format: Journal Article
• Language: English
• Published: Switzerland MDPI AG 22.05.2024; MDPI
• Subjects: Adhesive strength; Analysis; bulk-fill composite resin; cell viability; Composite materials; Curing; Dental pulp; Dentin; high irradiance; Light; Luminous intensity; Methods; Polymerization; Polymers; Resins; temperature; Thermocouples; Brazil; United States; United States > US; temperature; polymerization; cell viability; high irradiance; bulk-fill composite resin
• ISSN: 2073-4360; 2073-4360
• DOI: 10.3390/polym16111466

This study investigated effects of rapid high-intensity light-curing (3 s) on increasing transdentinal temperature and cell viability. A total of 40 dentin discs (0.5 mm) obtained from human molars were prepared, included in artificial pulp chambers (4.5 × 5 mm), and subjected to four light-curing protocols (n = 5), with a Valo Grand light curing unit: (i) 10 s protocol with a moderate intensity of 1000 mW/cm (Valo-10 s); (ii) 3 s protocol with a high intensity of 3200 mW/cm (Valo-3 s); (iii) adhesive system + Filtek Bulk-Fill Flow bulk-fill composite resin in 10 s (FBF-10 s); (iv) adhesive system + Tetric PowerFlow bulk-fill composite resin in 3 s (TPF-3 s). Transdentinal temperature changes were recorded with a type K thermocouple. Cell viability was assessed using the MTT assay. Data were analyzed using one-way ANOVA and Tukey tests for comparison between experimental groups ( < 0.05). The 3 s high-intensity light-curing protocol generated a higher temperature than the 10 s moderate-intensity standard ( < 0.001). The Valo-10 s and Valo-3 s groups demonstrated greater cell viability than the FBF-10s and TPF-3 s groups and statistical differences were observed between the Valo-3 s and FBF-10 s groups ( = 0.023) and Valo-3 s and TPF-3 s ( = 0.025), with a potential cytotoxic effect for the FBF-10 s and TPF-3 s groups. The 3 s rapid high-intensity light-curing protocol of bulk-fill composite resins caused a temperature increase greater than 10 s and showed cell viability similar to and comparable to the standard protocol.