ABSTRACT
Statement of the Problem: Endodontic irrigants and medicaments may affect the bond strength of intracanal posts to root dentin
Purpose: The aim of this study was to compare the effect of calcium hydroxide [Ca[OH][2]] and 2% chlorhexidine gel [CHX] on bond strength of fiber post cemented with resin cement to root dentin
Materials and Method: This in vitro experimental study was conducted on 36 mandibular premolars. Canals were prepared using the step back technique. After root canal irrigation, the teeth were divided into three groups of 12. Ca[OH][2] paste and CHX gel were used as intracanal medicaments in the first and second groups respectively. No intracanal medicament was used in the third group [control group]. Access cavities were then sealed and the teeth were incubated for one week. The root canals were then filled using gutta percha and AH26 sealer and the teeth were incubated for 72 hours. Tooth crowns were then cut at the level of the cementoenamel junction and intracanal posts were placed. The teeth were mounted in auto-polymerizing acrylic resin, and incubated for one week .They were then sectioned into 1.5mm thick slices from their coronal surface using a fully automated cutting machine, and subjected to push-out test until failure. The load at debonding was recorded and data were analyzed using one-way ANOVA, post-hoc test and t-test. The coronal margin of the root was at the level of the surface of acrylic resin in the mold
Results: The mean bond strength was 4.45 MPa in the Ca[OH][2], 2.45 MPa in the CHX and 2.48 MPa in the control group. The difference in this regard was statistically significant among groups [p= 0.04]. The Ca[OH][2] group had significant differences with the CHX and control groups [p= 0.03 and p= 0.02, respectively]. The difference between the CHX and control groups was not significant [p= 0.974]
Conclusion: Based on the results, Ca[OH][2] increased the bond strength of fiber post to root dentin but 2% CHX had no effect on bond strength
ABSTRACT
Objective: Considering the use of triple antibiotic paste [TAP] for root canal treatment of open apex teeth, this study aimed to assess the effect of TAP and calcium hydroxide [CH] on bond strength of composite to dentin
Methods: This in-vitro study was conducted on 32 extracted human premolar teeth. After disinfection with 2% thymol solution, the enamel on the buccal surface of specimens was removed to expose a smooth dentin surface parallel to the long axis of the teeth with approximately 19mm2 surface areas. Specimens were divided into three groups of 11, 10 and 11 specimens. In group one, TAP, in group two CH and in group three, saline solution were applied to dentin surfaces for 14 days. After removal of medicaments, composite cylinders were bonded to the dentin surfaces using a bonding agent. Shear bond strength was measured in an Instron machine at a crosshead speed of 1mm/min. Data were analyzed using one-way ANOVA
Results: The highest mean bond strength belonged to the control group [14.4760 MPa] and the lowest belonged to the TAP group [11.5808 MPa]. The mean bond strength in CH group was less than that of the control and higher than that of the TAP group [11.7834 MPa]. However, the difference among the three groups was not statistically significant [p=0.327]
Conclusion: Use of medicaments such as CH and TAP has no effect on bond strength of composite to dentin
ABSTRACT
PURPOSE: Post surface conditioning is necessary to expose the glass fibers to enable bonding between fiber post and resin cement. The purpose of the present study was to evaluate the effect of different surface conditioning on tensile bond strength (TBS) of a glass fiber reinforced post to resin cement. MATERIALS AND METHODS: In this in vitro study, 40 extracted single canal central incisors were endodontically treated and post spaces were prepared. The teeth were divided into four groups according to the methods of post surface treatment (n=10): 1) Silanization after etching with 20% H2O2, 2) Silanization after airborne-particle abrasion, 3) Silanization, and 4) No conditioning (Control). Adhesive resin cement (Panavia F 2.0) was used for cementation of the fiber posts to the root canal dentin. Three slices of 3 mm thick were obtained from each root. A universal testing machine was used with a cross-head speed of 1 mm/minute for performing the push-out tests. Two-way ANOVA and Tukey post hoc tests were used for analyzing data (alpha=0.05). RESULTS: It is revealed that different surface treatments and root dentin regions had significant effects on TBS, but the interaction between surface treatments and root canal regions had no significant effect on TBS. There was significant difference among H2O2 + Silane Group and other three groups. CONCLUSION: There were significant differences among the mean TBS values of different surface treatments. Application of hydrogen peroxide before silanization increased the bond strength between resin cements and fiber posts. The mean TBS mean values was significantly greater in the coronal region of root canal than the middle and apical thirds.