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Study of light intensity variation in photoactivation processes of dental composite resins and their effects to minimize the polymerization contraction

Grant number: 17/08188-0
Support type:Scholarships in Brazil - Scientific Initiation
Effective date (Start): April 01, 2018
Effective date (End): March 31, 2019
Field of knowledge:Physical Sciences and Mathematics - Mathematics - Applied Mathematics
Principal Investigator:Rafael Plana Simões
Grantee:Gabriel Felipe Guimaraes
Home Institution: Faculdade de Ciências Agronômicas (FCA). Universidade Estadual Paulista (UNESP). Campus de Botucatu. Botucatu , SP, Brazil


Composite resins are the most commonly materials used for direct dental restorations. The aesthetic results of these restorations are excellent, however, some mechanical behavior during and after the photopolymerization process can be unsatisfactory, especially the high polymerization shrinkage. Several researches have been dedicated studies to the improvement of the polymerization process, proposing adaptations in the chemical compositions of the resins. However, there are still few studies that focus on improvements to promote a technical-operational standardization for Dental Surgeons during the polymerization process. In view of the above, this project proposes a systematic study to optimize the function of light intensity variation during photoactivation processes. For this study, we will use mathematical techniques for optimization of nonlinear objective functions, aiming the determination of a function (or a set of functions) that can promote the minimization of the polymerization shrinkage. These functions will be incorporated in an alternative photopolymerizator, which has already been developed by the research group. The effectiveness of the minimization functions will be evaluated by monitoring the polymerization shrinkage during photoactivation and compared with the same result for applying conventional, pulse-delay and soft-start photoactivation methods. The quality of the polymerized resins will be evaluated by Knoop hardness and the degree of conversion of monomers in to polymers, comparing statistically the obtained results for the different photoactivation methods. (AU)