Influence of photodynamic therapy and intracanal medication on Martens hardness, elastic modulus and bond strength of glass-fiber posts to endodontically treated root dentin.

Background: The purpose of this in vitro study was to evaluate the influence of photodynamic therapy (PDT) with methylene blue photosensitizer (PS) and calcium hydroxide intracanal medication on Martens hardness (MH), elastic modulus (Eit) and adhesive bond strength of glass-fiber posts in different thirds of intraradicular dentin.

Methods: Ninety-six bovine teeth were distributed into the following 6 experimental groups: a negative control irrigated with deionized water; a positive control irrigated with deionized water and filled with calcium hydroxide intracanal medication (Ca[OH]); Ca[OH] + methylene blue 50 mg/L without activation; Ca[OH] + methylene blue 100 mg/L without activation; Ca[OH] + methylene blue 50 mg/L activated by red laser; and Ca[OH] + methylene blue 100 mg/L activated by red laser (n = 16). MH and Eit were measured using an ultramicrodurometer under load action of 3 mN (n = 8).