title: The influence of time and cement type on push-out bond strength of fiber posts to root dentin.
abstract: The bond strength of fiber posts luted with resin cements was evaluated after two storage times in different regions of a post space. A total of 40 single-rooted human teeth were endodontically treated and prepared for cementation of fiber posts (White Post DC). In groups 1 and 3 (G1 and G3, respectively), posts were luted with RelyX ARC, whereas the posts in groups 2 and 4 (G2 and G4, respectively) were luted with RelyX Unicem. After one month of storage at 100% humidity, G1 and G2 were transversally sectioned in 1.7-mm slices of the cervical (C), middle (M), and apical (A) thirds of the post space and submitted to push-out testing at 1 mm/min. After nine months of storage, the roots of G3 and G4 underwent the same process. Mean values were analyzed using the Mann-Whitney and Kruskal-Wallis tests (α=0.05). The bond strengths in G2 (C=4.26±2.29; M=4.67±3.54; A=7.27±4.30) were statistically higher than in G1 (C=3.81±1.07; M=1.57±1.62; A=1.99±1.60) in the middle and apical thirds (p=0.001). Bond strengths in G4 (C=3.36±1.39; M=4.49±2.17; A=3.83±1.92) were higher than in G3 (C=2.13±0.47; M=0.94±1.05; A=0.95±1.02) in all evaluated regions (p=0.02, p<0.001, and p<0.001, respectively). When comparing the root regions for each group, G1 had higher values in the cervical third than the middle third (p=0.02). The self-adhesive resin cement showed better results than the conventional resin cement at both storage times. For both materials a similar performance among the three root regions was found. Storage time did not influence the shear bond strength.
authors.affiliation: Cidade Universitária, Campo Grande, MS-Brazil.
authors.forename: A A
authors.initials: AA
authors.lastname: Leme
authors.forename: M
authors.initials: M
authors.lastname: Coutinho
authors.forename: A F
authors.initials: AF
authors.lastname: Insaurralde
authors.forename: P M C
authors.initials: PM
authors.lastname: Scaffa
authors.forename: L M
authors.initials: LM
authors.lastname: da Silva
mesh_terms: D017438:Bisphenol A-Glycidyl Methacrylate; D002484:Cementation; D003188:Composite Resins; D003799:Dental Stress Analysis; D003804:Dentin; D017220:Dentin-Bonding Agents; D004356:Drug Storage; D005898:Glass; D006801:Humans; D008422:Materials Testing; D011092:Polyethylene Glycols; D011109:Polymethacrylic Acids; D011176:Post and Core Technique; D019279:Resin Cements; D033081:Shear Strength; D018709:Statistics, Nonparametric; D013997:Time Factors; D019553:Tooth, Nonvital
chemical_list: D003188:Composite Resins; D017220:Dentin-Bonding Agents; D011109:Polymethacrylic Acids; C483701:Rely X Unicem; C462240:RelyX ARC; D019279:Resin Cements; C425844:Scotchbond Multi-Purpose Plus; C009753:fiberglass; D011092:Polyethylene Glycols; D017438:Bisphenol A-Glycidyl Methacrylate