Nd:YAG laser irradiation at a fluence of 46.9 J/cm(2) roughens the sandblasted surface of a Co-Cr alloy and increases the strength of the bond between PMMA and the alloy. This bond strength can be increased further by applying a metal primer to the laser-irradiated surface.

BackgroundThe study investigated the fracture resistance of root-filled maxillary premolars with class II cavities restored by different restorations.MethodsA total of 55 intact maxillary premolar teeth were included (n = 11). G1 as positive control group, 44 teeth underwent root canal treatment, and MOD cavities were prepared. (G2) no restoration, (G3) direct composite restoration, (G4) direct composite strengthened with buccal to lingual pre-impregnated glass-fibers and (G5) ceramic inlay restoration. After thermocycling, fracture resistance test was performed and fracture type was recorded. Data were analyzed with one-way ANOVA and Chisquare test.ResultsThe mean fracture resistance was as follows: G1 had the highest fracture resistance, G2 had the lowest (p < 0.05). There were no significant differences between the fracture resistance values of the groups that underwent different restorations (G3, G4, G5) (p > 0.05). According to fracture type, the groups showed similar results (p > 0.05). A significant level of unrestorable fracture was detected in G5 (ceramic inlay) (p < 0.05).ConclusionsAll of the restoration techniques investigated herein increased the fracture strength of teeth; however, all of these values were lower than the fracture resistance of intact teeth. There were no significant differences between the fracture resistance values of the groups that underwent different restorations.

Within the limits of this in vitro study, aesthetic ceramic veneering of CAD/CAM-generated copings caused a statistically significant but tolerable loss of marginal fit precision.

Objectives: The purpose of this in-vitro study was to evaluate the effect of 3-different post-space on the bond strength of fiber post. Study design: Fifty-four extracted human maxillary incisors were selected and their roots were treated endodontically. The roots were prepared according to different post spaces (Torpan Drill ISO 100(D100), 120(D120) and Enapost Drill ISO 140(D140), and divided into three groups. Snowposts were used, and the posts were cemented with three different dual polymerized resin luting agents: Panavia F, NX3 and Rely X. The specimens were subjected to a pullout test using a universal testing machine at a cross-head speed of 0.5 mm/min. The maximum force required to dislodge each post was recorded. Data were analyzed using the two way ANOVA and Tukey multiple comparisons tests. Results: According to the results of Tukey test, the bond strength values of the Panavia F luting cements was significantly higher in D120 post space; otherwise, there were no significant differences between Rely X and NX 3. Conclusions: It had been seen that cement thickness affects the pullout strengths of fiber-reinforced posts.

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