Composite resin's adhesive resistance to dentin: influence of Er:YAG laser focal distance variation.
The aim of this study was to analyze in vitro the influence of Er:YAG laser focal distance variation on tensile bond strength of a composite resin to dentin. Although there are several studies using the Er:YAG laser for dentin treatment, there is a lack of available literature related to the Er:YAG laser focal distance variation. Sixty vestibular and lingual dentin surfaces from extracted human third molars, kept in a 0.4% azide sodium solution, were ground and assigned to six groups. The control group was conditioned with 35% phosphoric acid (CA). In the lased groups, the dentin surface treatment was performed by irradiation with Er:YAG laser (80 mJ/2 Hz), varying the focal distance (11, 12, 14, 16, and 17 mm), followed by acid etching. The Single Bond/Filtek Z250 (3M) resinous system was used for the specimen manufacture. The tensile bond strength tests were performed in a Universal Testing Machine with 50 kgf load cell and 0.5 mm/min cross head speed. The averages in MPa were: CA: 18.03 (+/-2.09); 11 mm; 9.92 (+/-3.34); 12 mm: 9.49 (+/-2.29); 14 mm: 10.99 (+/-3.45); 16 mm: 10.56 (+/-1.93); and 17 mm: 17.05 (+/-2.31). It was concluded that the application of Er:YAG laser in a defocused mode (17 mm) associated with acid etching was similar to the treatment of acid solely. Er:YAG laser irradiation in a focused (12 mm) and a defocused (11, 14, and 16 mm) mode coupled with acid conditioning produced the lowest values of adhesion.
Corona
Silmara Aparecida Milori
SA
Ribeirão Preto School of Dentistry, University of São Paulo, São Paulo, Brazil. nelsoncorona@uol.com.br
Atoui
Juliana Abdallah
JA
Chimello
Daniela Thomazatti
DT
Borsatto
Maria Cristina
MC
Pecora
Jesus Djalma
JD
Dibb
Regina Guenka Palma
RG
D000134:Acid Etching, Dental; D000268:Adhesiveness; D017438:Bisphenol A-Glycidyl Methacrylate / Q000737:chemistry / Q000528:radiation effects*; D003188:Composite Resins / Q000737:chemistry / Q000528:radiation effects*; D001840:Dental Bonding; D003763:Dental Leakage / Q000517:prevention & control; D003793:Dental Restoration, Permanent; D017220:Dentin-Bonding Agents / Q000737:chemistry / Q000528:radiation effects*; D006801:Humans; D066298:In Vitro Techniques; D007834:Lasers; D008422:Materials Testing; D008963:Molar; D013718:Tensile Strength
D003188:Composite Resins; D017220:Dentin-Bonding Agents; C115612:single bond; D017438:Bisphenol A-Glycidyl Methacrylate