Effect of the addition of filler particles and a blue lightsensitive photoinitiator system on the phisical/chemical properties and internal/marginal fit of 3D-printing resin materials for provisional crowns

Author(s)

Amanda Endres Willers

• Document type: Doctoral Thesis
• Press: Piracicaba, SP.
• Institution: Universidade Estadual de Campinas (UNICAMP). Faculdade de Odontologia de Piracicaba (FOP)
• Defense date: 2024-04-29

Examining board members

Marcelo Giannini; Américo Bortolazzo Correr; Vanessa Cavalli; Estevam Augusto Bonfante; Carlos Alberto Kenji Shimokawa

• Advisor: Marcelo Giannini

Abstract

The aim of this study was to investigate the effect of the incorporation of silanized filler particles and a blue light-sensitive photoiniator system (TPS) on the mechanical and physical properties, as well as the internal and marginal fit, of three-dimensional (3D) printed resins used for provisional crowns. The experimental design of this study has 3 factors: 1- 3D resins (Smart Print Temp/SP, Resilab 3D Temp/RL, and Cosmos Temp/CT), 2- Filler Particles (0, 5, 10 or 30% by weight (wt%) of 0.05????m colloidal silica and 0.7????m barium borosilicate), and 3- TPS (with or without the addition of tertiary amine + camphorquinone + iodonium salt). Samples were printed (3D Printer, W3D, Wilcos do Brasil) and submitted to the following initial evaluations: flexural strength (n=10), flexural modulus (n=10), sorption and solubility (n=5), scanning electron microscopy (SEM) and energy dispersive x-ray spectroscopy (EDS) (n=3). Complementary evaluations were carried out considering the same 3 factors, but only with one concentration of filler particles (30wt%): fatigue resistance (n = 18), assessed with step-stress accelerated-life testing, and internal and marginal fit, as well as the volume of cement space (n=10). For fatigue resistance, the use level probability Weibull curves at 500 N were plotted and the reliability at 200 and 500 N was calculated for a mission of 50,000 cycles (90% CI). For the other evaluations, the obtained data was analyzed by Generalized Linear Models (?=0.05). Initial results indicated that the incorporation of TPS and 30wt% of filler particles led to an improvement in flexural strength. Flexural modulus strength demonstrated a proportional increase with the concentration of filler particles and TPS. The incorporation of filler particles and TPS decreased sorption and increased solubility. SEM and EDS analyses revealed a progressive impact on layer deposition due to the agglomeration of filler particles, which proportionally corresponded to an increase in filler particles concentration. Complementary results demonstrated that there were no differences of probability of survival among the tested groups for both estimated missions (200 N and 500 N) when 30wt% of filler particles and TPS were added. At 200 N the reliability of all groups was greater than 95%, while at 500 N, CT (71-72%) and SP (48-80%) with the addition of 30wt% of filler particles exhibited a significant decrease in probability of survival. The characteristic strength significantly improved for RL (994 – 1181 N) and CT (760 – 867 N) with the addition of 30wt% filler particles and TPS. The incorporation of TPS and filler particles worsened the internal (p<0.001) and marginal fit (p<0.001), increasing the cement space at occlusal face and decreasing the cement space of axial walls, for all tested materials. The volume was also significantly affected (p<0.001), especially for RL and CT. In conclusion, the incorporation of filler particles and TPS enhanced the tested mechanical and physical properties of the 3D resins, however, filler particles showed propensity for agglomeration. The probability of survival for all tested materials was consistent with clinical requirements for provisional crowns, regardless of the addition of filler particles and TPS. Nonetheless, the incorporation of both compounds promoted a significant internal and marginal misfit, as well as an increase in the volume of cement space (AU)

• FAPESP's process: 20/01815-1 - Improvement of properties related to mechanical strength, polymerization and dimensional stability of polymeric materials for interim restorations made by 3D printing
• Grantee: Amanda Endres Willers
• Support Opportunities: Scholarships in Brazil - Doctorate