جستجوی مقالات مرتبط با کلیدواژه "push-out test" در نشریات گروه "پزشکی"

 The most common causes of fiber post-failure are inadequate restorations and dislodgement. This study aimed to evaluate fiber post-bond strength to dentin following Er, Cr: YSGG laser irradiation.

 A total of 65 human mandibular premolars with single roots were included. The 14 mm root length was instrumented with the rotary system using the crown-down technique. Gutta-percha was used for obturation, followed by conventional post-space preparation. The samples were divided into two major groups: control (A) and Er, Cr: YSGG (2780 nm) laser group (B). The laser group was subdivided into (B1) 1.25 W, (B2) 1.5 W, and (B3) 1.75 W. All laser groups were set at 20 Hz, 10% and 30% water/air ratio. Fiber posts were cemented with selfadhesive cement. Each sample was divided horizontally into two slices, coronal and apical. The universal testing equipment was used to conduct a push-out test. All groups were examined by SEM and temperature changes. The statistical analysis was performed by using one-way ANOVA and Tukey HSD tests.

 SEM images of all laser groups revealed the elimination of the smear layer and opened dentinal tubules, which was particularly noticeable in the apical region with no thermal risk to the periodontal tissue. In the push-out test, all laser groups had highly significant (P<0.001) increases in the bond strength of fiber post-to-dentin. The failure mode of the control group was a predominantly adhesive failure, whereas the laser groups were a predominantly mixed type.

 The three laser protocols can be used safely in the surface treatment of the fiber post space of endodontically treated teeth. Laser helps to increase the bond strength of fiber post to dentin, especially in the apical area.

Attempts are ongoing to simplify the bonding procedure by decreasing the procedural steps. Universal adhesives were introduced to serve this purpose. This study aimed to evaluate the push-out bond strength of glass fiber posts in endodontically-treated teeth with two universal adhesives. 

In this in vitro, experimental study, 22 single-rooted mandibular premolars were decoronated at their cementoenamel junction, endodontically treated and were randomly divided into two groups. The G-Premio Bond was used in the first and All-Bond Universal was used in the second group, according to the manufacturers’ instructions. Angelus fiber posts were cemented using RelyX U200 Automix self-adhesive resin cement. The roots were cut into 1-mm-thick sections perpendicular to the longitudinal axis of the tooth in the cervical, middle, and apical thirds. The push-out test was performed in a universal testing machine at a crosshead speed of 1 mm/min, and bond strength values were recorded. The failure modes were also determined. The data were analyzed using ANOVA and linear mixed models.

The mean push-out bond strength was significantly higher in All Bond Universal than
G-Premio Bond (P=0.036). Also, there were statistically significant differences in the push-out bond strength of adhesives in different parts of the root canal (P=0.039). All failures were type 4 in both groups (adhesive failure between the dentin and resin cement).

All Bond Universal yielded superior push-out bond strength than G-Premio. However, further in vitro and in vivo studies with larger sample size are required for an evidence-based decision making.

The aim of this study was to evaluate the effect of a new imidazolium-based silver nanoparticle (ImSNP) root canal irrigant on the bond strength of AH-Plus sealer to root canal dentine. Forty single-rooted extracted human teeth were used in this study. The crowns were resected and according to the irrigation solutions used during root canal preparation, the roots were divided into 5 groups (n=8): Group 1: normal saline (control group), Group 2: 2.5% Sodium Hypochlorite (NaOCl), Group 3: 2.5% NaOCl+17% ethylene diamin tetracetic acid (EDTA), Group 4: silver nanoparticles (AgNPs), Group 5: AgNPs +17% EDTA. After root canal instrumentation, the canals were filled with AH-Plus. Then, after 7 days, 2 or 3 dentine disks were obtained from the mid-root of each sample. Bond strength was measured by the push-out test. Additionally, failure patterns were classified as adhesive, cohesive and mixed. Data were statistically analyzed by one-way ANOVA and Tamhane post hoc tests. The level of significance was set at 0.05. There was no statistically significant differences between groups (P>0.05). Groups 4 (AgNPs), 3 (2.5% NaOCl+17% EDTA) and 2 (2.5% NaOCl) showed statistically higher bond strength compared to group 1 (control group) (P<0.05). Also, Group 4 showed a significant difference with group 5 (AgNPs+17% EDTA) (P=0.017). The failure patterns were mainly cohesive. This in vitro study showed that, when used without EDTA, AgNPs improved the bond strength of AH-Plus to radicular dentine.

The aim of this study is to analyze the effect of G-Bond and Z-PRIME Plus on the bond strength between prefabricated zirconia posts and the canal wall.
Material and The study was carried out on 21 premolar teeth with similar conditions. The collected samples were cut at the CEJ. After root canal treatment of the roots, the post space was prepared with a length of 10mm. The samples were randomly allocated into two groups of 10. G-bond was used in one group and Z-PRIME plus in the other to prepare the posts’ surface. After cementation and mounting the samples in polyester, the post was cut from the apical area into three equal sections. The bond strength of the samples was tested using the push out on a universal testing machine. The acquired data was analyzed using the T-Test.
The average for the control group was 14.3N, the G-bond group had an average of 27.6±11.8N and the Z-PRIME plus group’s average was 27.4±13.4N. There is no statistically significant relationship between the two groups (P There is no statistically significant relationship between the G-bond and Z-prime plus groups and both products increase the bond strength of prefabricated zirconia posts.

Mineral trioxide aggregate (MTA) can be used in the treatment of irritated vital pulp and repair of root perforations. However, the initial reaction of inflammatory cells to this material and also its setting time are not ideal. Studies have shown that disodium hydrogen phosphate (DHP), decreases the setting time of MTA, with no effect on its pH. This study was undertaken to evaluate the effect of DHP on push-out bond strength of MTA at different liquid-to-powder ratios.
Methods and Materials: A total of 120 samples were prepared from the middle third of the roots of single-rooted teeth for evaluation of push-out bond strength. The push-out bond strength was measured in both groups after 72 h at different liquid-to-powder ratios, including 0.33:1, 0.5:1 and 0.6:1. Factorial ANOVA and Tukey’s HSD post-hoc tests were used to compare the differences between the independent groups. Statistical significant was set at P The push-out bond strengths of pure MTA and MTA౳ groups were 10.96±5.78 and 13.32±5.03, respectively. Tukey’s HSD post-hoc test revealed significant differences between the two groups. Furthermore, there were no interactive effect between material and the liquid: powder ratio.
Incorporation of DHP into MTA resulted in an increase in push-out bond strength of MTA, and an increase in liquid-to-powder ratio resulted in a decrease in push-out bond strength.