Vinícius E Salgado1, Pedro Paulo A C Albuquerque2, Larissa Maria Cavalcante3, Carmem S Pfeifer4, Rafael R Moraes5, Luis Felipe J Schneider6. 1. Graduate Program in Dentistry, Federal University of Pelotas, Pelotas, RS, Brazil. Electronic address: salgadouff@gmail.com. 2. Department of Biomaterials and Oral Biology, School of Dentistry, University of São Paulo, São Paulo, SP, Brazil. 3. Department of Restorative Dentistry, Federal Fluminense University, Niterói, RJ, Brazil. 4. Department of Biomaterials and Biomechanics, School of Dentistry, Oregon Health & Science University, Portland, OR, USA. 5. Graduate Program in Dentistry, Federal University of Pelotas, Pelotas, RS, Brazil. 6. Department of Restorative Dentistry, Federal Fluminense University, Niterói, RJ, Brazil; Graduate Program in Dentistry, School of Dentistry, Veiga de Almeida University, Rio de Janeiro, RJ, Brazil. Electronic address: felipefop@gmail.com.
Abstract
OBJECTIVE: To establish the relationship between photoinitiator system and nanofiller size on the optical properties and cure efficiency of model composites. METHODS: Model composites based on BisGMA/TEGDMA (60:40mol%) were loaded with 40wt% of 7nm or 16nm-sized filler particles. One of the following photoinitiator systems was added: camphorquinone (CQ) associated with an amine (EDMAB), monoacylphosphine oxide (TPO), or bysacylphosphine oxide (BAPO). The optical properties of disk-shaped specimens were measured 24h after curing and repeated after storage in water for 90 days and coffee for 15 days. A large spectrum LED unit (Bluephase G2, Ivoclar Vivadent) was used for photoactivation. CIE L*a*b* parameters, color difference (ΔE), and translucency parameter (TP) were calculated. Knoop hardness readings were taken at top and bottom composite surfaces. Cure efficiency was determined by bottom/top hardness ratio. Data were statistically analyzed at α=0.05 significance level. RESULTS: Composites formulated with 16nm particles had higher CIE L* than those with 7nm particles in all storage conditions. BAPO-based composites generally had lower CIE a* than the other composites. The group TPO+16nm before storage and all groups with 16nm-sized particles after storage had lower CIE b* (i.e. lower degree of yellowing) than the other groups. TPO-based materials had higher color stability. The cure efficiency was not significantly affected by photoinitiator system or particle size. CQ+7nm had the lowest and BAPO+16nm the highest hardness values. SIGNIFICANCE: Combination of photoinitiator system and filler particle size might affect the optical properties of composites, with low influence on cure efficiency.
OBJECTIVE: To establish the relationship between photoinitiator system and nanofiller size on the optical properties and cure efficiency of model composites. METHODS: Model composites based on BisGMA/TEGDMA (60:40mol%) were loaded with 40wt% of 7nm or 16nm-sized filler particles. One of the following photoinitiator systems was added: camphorquinone (CQ) associated with an amine (EDMAB), monoacylphosphine oxide (TPO), or bysacylphosphine oxide (BAPO). The optical properties of disk-shaped specimens were measured 24h after curing and repeated after storage in water for 90 days and coffee for 15 days. A large spectrum LED unit (Bluephase G2, Ivoclar Vivadent) was used for photoactivation. CIE L*a*b* parameters, color difference (ΔE), and translucency parameter (TP) were calculated. Knoop hardness readings were taken at top and bottom composite surfaces. Cure efficiency was determined by bottom/top hardness ratio. Data were statistically analyzed at α=0.05 significance level. RESULTS: Composites formulated with 16nm particles had higher CIE L* than those with 7nm particles in all storage conditions. BAPO-based composites generally had lower CIE a* than the other composites. The group TPO+16nm before storage and all groups with 16nm-sized particles after storage had lower CIE b* (i.e. lower degree of yellowing) than the other groups. TPO-based materials had higher color stability. The cure efficiency was not significantly affected by photoinitiator system or particle size. CQ+7nm had the lowest and BAPO+16nm the highest hardness values. SIGNIFICANCE: Combination of photoinitiator system and filler particle size might affect the optical properties of composites, with low influence on cure efficiency.
Authors: Luis Felipe Marques de Resende; Anderson Catelan; Kusai Baroudi; Alan Rodrigo Muniz Palialol; Alexandre Marques de Resende; Ana Carolina Andreucci; Rayssa Ferreira Zanatta; Priscila Christiane Suzy Liporoni Journal: Eur J Dent Date: 2021-08-24