001). The mean fracture resistances (N) were: Gr1 = 1168 ± 157,a check details Gr2 = 360 ± 110,d Gr3 = 1026 ± 188,b Gr4 = 887 ± 143,c Gr5 = 1007 ± 132,b Gr6 = 810 ± 164,c Gr7 = 1033 ± 218,a Gr8 = 955 ± 147,ab Gr9 = 780 ± 86c (groups with the same superscript letter indicate statistical similarity). Combining an OX with three resin cements
had a significant negative effect on the fracture resistance of premolars restored with composite inlay cemented with Panavia F2.0 and Variolink II, but it had no significant effect when cemented with Duolink. “
“Purpose: To investigate the reliability of titanium abutments veneered with indirect composites for implant-supported crowns and the possibility to trace back the fracture origin by qualitative fractographic analysis. Materials and Methods: Large base (LB) (6.4-mm diameter base, with a 4-mm high cone in the center for composite retention), small base (SB-4) (5.2-mm base, 4-mm high cone),
and small base with cone shortened to 2 mm (SB-2) Ti abutments were used. Each abutment received incremental layers of indirect resin composite until completing the anatomy of a maxillary molar crown. Step-stress accelerated-life fatigue https://www.selleckchem.com/btk.html testing (n = 18 each) was performed in water. Weibull curves with use stress of 200 N for 50,000 and 100,000 cycles were calculated. Probability Weibull plots examined the differences between groups. Specimens were inspected in light-polarized and scanning electron microscopes for fractographic analysis. Results: Use level probability Weibull plots showed Beta values HSP90 of 0.27 for LB, 0.32 for SB-4, and 0.26 for SB-2, indicating that failures were not influenced by fatigue and damage accumulation. The data replotted as Weibull distribution showed no significant difference in the characteristic strengths between LB (794 N) and SB-4 abutments (836 N), which were both significantly higher than SB-2 (601 N). Failure mode was cohesive within the composite for all groups. Fractographic markings
showed that failures initiated at the indentation area and propagated toward the margins of cohesively failed composite. Conclusions: Reliability was not influenced by abutment design. Qualitative fractographic analysis of the failed indirect composite was feasible. “
“The following article from Journal of Prosthodontics, “Effect of Chemical Disinfectants and Repair Materials on the Transverse Strength of Repaired Heat-Polymerized Acrylic Resin,”[4] by Ayman E. Ellakwa and Ali M. El-Sheikh, published online on September 4, 2006 in Wiley Online Library (http://wileyonlinelibrary.com), has been retracted by agreement between the authors, the journal Editor-in-Chief, Dr. David A. Felton and Wiley Periodicals, Inc.