Optical parameters and hardness of two maxillofacial elastomers after immersion in different solutions of Brazilian green propolis extract - Miranda, Nathalia Bahia; Arruda, Jose Alcides Almeida; Almdeida, Sandra Barbosa Moraes; Santos, Emerson Gomes; Medeiros, Igor Studart; Moreno, Amalia (The Journal of Prosthetic Dentistry, 2019)