ObjectiveThe purpose of this study was to assess the push-out bond strength of glass fiber
posts to root dentin after cementation with glass ionomer (GICs) and
resin-modified glass ionomer cements (RMGICs).Material and MethodsFifty human maxillary canines were transversally sectioned at 15 mm from the apex.
Canals were prepared with a step back technique until the application of a #55
K-file and filled. Post spaces were prepared and specimens were divided into five
groups according to the cement used for post cementation: Luting & Lining
Cement; Fuji II LC Improved; RelyX Luting; Ketac Cem; and Ionoseal. After
cementation of the glass fiber posts, all roots were stored at 100% humidity until
testing. For push-out test, 1-mm thick slices were produced. The push-out test was
performed in a universal testing machine at a crosshead speed of 0.5 mm/minute and
the values (MPa) were analyzed by Kolmogorov-Smirnov and Levene's tests and by
two-way ANOVA and Tukey's post hoc test at a significance level
of 5%.ResultsFiber posts cemented using Luting & Lining Cement, Fuji II LC Improved, and
Ketac Cem presented the highest bond strength to root dentin, followed by RelyX
Luting. Ionoseal presented the lowest bond strength values (P>0.05). The post
level did not influence the bond strength of fiber posts to root dentin (P=0.148).
The major cause of failure was cohesive at the cement for all GICs and RMGICs.ConclusionsExcept for Ionoseal, all cements provided satisfactory bond strength values.
This study aimed to evaluate morphometrically the bone formation and immunohistochemically the expression of vascular endothelial growth factor (VEGF) and metalloproteinase (MMP)-2 and -9 during the healing of critical-size defects treated with sintered anorganic bone (sAB). The 8-mm diameter full-thickness trephine defects created in the parietal bones of rats were filled with sAB (test group) or blood clot (CSD-control group). At 7, 14, 21, 30, 90 and 180 days postoperatively (n = 6/period) the volume of newly formed bone and total number of immunolabeled cells (Ntm) for each protein were determined. Bone formation was smaller and faster in the CSD-control group, stabilizing at 21 days (6.74 mm(3)). The peaks of VEGF, MMP-2 and MMP-9 occurred at 7 and 14 days in fibroblasts and osteoblasts, with mean reduction of 0.80 time at 21 days, keeping constant until 180 days. In the test group, sAB provided continuous bone formation between particles throughout all periods. The peak of MMP-2 was observed at 7-14 days in connective tissue cells and for VEGF and MMP-9 at 30 days in osteoblasts and osteocytes. Ntm for VEGF, MMP-2 and MMP-9 were in average, respectively, 3.70, 2.03 and 5.98 times higher than in the control group. At 180 days, newly formed bone (22.9 mm(3)) was 3.74 times greater in relation to control. The physical and chemical properties of sAB allow increased autocrine expression of VEGF, MMP-2 and MMP-9, favoring bone formation/remodeling with very good healing of cranial defects when compared to natural repair in the CSD-control.
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