Fracture Resistance of Endodontically Treated Teeth Restored with Biodentine, Resin Modified GIC and Hybrid Composite Resin as a Core Material

Patterns of Post-Endodontic Restoration: A Nationwide Survey of Dentists in Turkey

Developments in materials and techniques, geographical locations, age, specialty, and affiliations of dental practitioners affect the preference of post-endodontic restoration. Thus, this survey aimed to evaluate the trends of dentists in Turkey in terms of post-endodontic restorations. An anonymous survey containing 10 questions regarding demographics, post-endodontic restoration patterns, and factors affecting restoration selection was electronically delivered to the dentists registered in the database of the Turkish Dental Association. The data were analyzed using by a chi-square test and ordinal logistic regression analysis. A total of 1093 surveys from 20,564 participants were collected with a response rate of 5.3%. Half of the participants (52%) preferred composite resins for post-endodontic restorations. Usage of posts was less prevalent amongst prosthodontists and dentists with clinical experience of more than 20 years compared to endodontists (p < 0.001) and dentists with clinical experience of less than 5 years (p = 0.004). More than half of the participants (56%) utilized fiber posts. Composite resins and fiber posts were the most common preferences in post-endodontic restoration. Endodontists had a higher tendency to use posts than prosthodontists and general dental practitioners.

Comparison of Fracture Resistance of Endodontically Treated Teeth Restored with FiberSite Postsystem and Glass Fiber, Combined with Different Root Canal Sealers

This study is aimed at evaluating the effects of FiberSite and glass fiber postsystems on the fracture resistance of endodontically restored teeth, when combined with various root canal sealers. Forty human mandibular premolar teeth, each having a single root with anatomically comparable dimension and length, were selected. The teeth in each experimental group (n = 10) were instrumented, obturated, and restored with the following procedures: in group 1, AH Plus root canal sealer and a glass fiber post with a composite core; in group 2, AH Plus root canal sealer and a FiberSite postsystem; in group 3, Sure-Seal Root canal sealer and a glass fiber post with a composite core; and in group 4, Sure-Seal Root canal sealer and a FiberSite postsystem. The specimens were placed on a universal test machine. The fracture resistance of all specimens was tested using generic test equipment, and the value of the force in newton (N) during fracture was measured for each root. A statistical analysis was conducted through the Kruskal–Wallis test as well as the post hoc test. The tests showed a significant difference between groups 2 and 3, with group 3 producing load values that were significantly higher than group 2. In contrast, no significant differences were found to exist between the other groups. Regardless of postsystems, groups 3 and 4 showed higher mean fracture values (but no statistically significant differences) than groups 1 and 2.

Immediate and long-term microshear bond strength of resin-based cements to core build-up materials

Background

To evaluate the microshear bond strength (μ-SBS) between resin-based cements and core build-up materials after water storage.

Material and Methods

Cylinders (1x1 mm) of conventional dual-cure resin cement (RelyX ARC, 3M ESPE), universal dual-cure resin cement (RelyX Ultimate, 3M ESPE) or self-adhesive resin cement (RelyX U200, 3M ESPE) were adhered to disks (6x2 mm) made with commercial core build-up materials (Bis-Core, Bisco or LuxaCore Z, DMG) or conventional nanocomposite resin (Filtek Z350 XT, 3M ESPE). The specimens (n=10) were submitted to μ-SBS test using a universal testing machine and fracture pattern analysis at 48 hours or after 9 months of water storage. The data were evaluated by three-way ANOVA for repeated measures and Tukey’s test (α=0.05).

Results

After 48 hours, regardless of the resin-based cement used, the μ-SBS to the conventional resin composite (Filtek Z350 XT) was greater compared to other materials. However, after 9 months, there was a statistically significant decrease in μ-SBS values between the conventional resin composite and evaluated luting agents. The μ-SBS values of core build-up commercial materials (Bis-Core and LuxaCore Z) did not change over time. Regardless of the composite used and storage time, there was no statistically significant difference between the resin-based cements. After 48 h, the most prevalent failure was mixed for all groups. However, after 9 months, the core build-up materials showed a predominantly mixed fracture pattern whereas the resin composite presented an adhesive pattern.

Conclusions

Commercial core build-up materials achieved stable bonding performance with resin-based cements over time.

Key words:Composite resins, resin cement, dental restoration failure.

Shear Bond Strength of E. Max Ceramic Restoration to Hydraulic Calcium Silicate Based Cement (Biodentine): An In Vitro Study

OBJECTIVE

The purpose of this study was to evaluate the shear bond strength (SBS) of hydraulic calcium silicate (Biodentine) as a core material to the e.max ceramic restoration.

METHODS

Forty discs (6 mm diameter; 2 mm thickness) were fabricated from each core material, Hydraulic calcium silicate [Biodentine™, Septodont], resin composite [Filtek™Z250 XT, 3M ESPE], and resin-modified glass ionomer cement (RMGIC) [GC Fuji II LC, GC Corporation]. Dentine surfaces of 40 extracted human permanent molars were exposed and used as a control group. All specimens were mounted in self-curing acrylic resin. One hundred sixty IPS e.max discs were fabricated (4 mm diameter; 2 mm thickness) and cemented to the core specimens with Variolink N (IvoclarVivadent). After storage in distilled water (37oC; 24h), the specimens were thermocycled 1.500 times. SBS was tested using a universal testing machine at 0.05 mm/min crosshead speed. The fracture modes were determined by a stereomicroscope at ×20 magnification. Data were analyzed using one-way analysis of variance followed by Tukey's test (P=0.05).

RESULTS

The mean SBS values of four tested groups showed statistically significant differences (P<0.05). The resin composite group exhibited the highest SBS value (36.17±6.08 MPa), while the Biodentine had the lowest SBS value (21.86±3.18 MPa). Mixed failure mode was the most common failure type in all tested groups except in the Biodentine group, which had a predominantly cohesive failure.

CONCLUSION

The SBS of e.max ceramic restorations cemented with resin is affected by the type of core material. Biodentine core material had the lowest SBS to e.max restoration. However, when Biodentine is indicated to be used as core material for pulp preservation, it is recommended to be covered with a layer of resin composite material to enhance its bonding strength to the e.max restoration.

A comparative evaluation of fracture resistance of endodontically treated teeth using four different intraorifice barriers: An in vitro study

Aim:

The aim of this study is to evaluate and compare the fracture resistance of endodontically treated teeth using four intraorifice barriers.

Materials and Methods:

Fifty extracted single-rooted mandibular premolars were selected, decoronated, and prepared with rotary Protaper universal system and obturated with gutta-percha and AH Plus sealer. Samples were divided into five groups (n = 10) on the basis of intraorifice barrier material used. Group 1: Biodentine, Group 2: Conventional glass ionomer cement (GIC), Group 3: Resin-modified glass ionomer cement (RMGIC), Group 4: Nanohybrid composite, Group 5: No barrier (control).Except for control specimens, coronal 3-mm gutta-percha was removed and filled with different intraorifice barrier materials in respective groups. Fracture resistance of specimens was tested using universal testing machine.

Statistical Analysis Used:

One-way analysis of variance test and Post hoc Tukey's test.

Results:

Mean fracture resistance of all experimental groups (with intraorifice barriers placed) were higher than control group (no intraorifice barrier placed). Biodentine showed the highest mean fracture resistance while RMGIC showed the least and the difference between their mean fracture resistance was statistically significant. There was no statistically significant difference among other experimental groups.

Conclusion:

Placement of intraorifice barriers in endodontically treated teeth can significantly increase fracture resistance and this increase in fracture resistance is material dependent.

Retrospective analysis of survival rates of post-and-cores in a dental school setting

STATEMENT OF PROBLEM

The clinical survival of different types of post-and-core systems requires assessment.

PURPOSE

The purpose of this retrospective clinical study was to evaluate the clinical survival rate (CSR) of custom-fabricated cast metal and prefabricated (both metal- and fiber-reinforced composite resin post) post-and-cores as a function of patient- and restoration-related variables.

MATERIAL AND METHODS

A retrospective analysis was conducted on electronic charts indicating that these patients had received some type of post-and-core between January 2003 and January 2018. A total of 754 records were included in the analysis based on the inclusion criteria. Data were analyzed by using the Kaplan-Meier and Cox proportional hazards analysis.

RESULTS

Kaplan-Meier analysis demonstrated the mean survival time for each group to be 12.0 years for fiber-reinforced composite resin posts, 11.8 years for cast metal post-and-cores, and 10.2 years for prefabricated metal posts. Although the mean survival time differed by 1.8 years among groups, with prefabricated metal posts having a slightly higher risk of failure, this effect was not statistically significant (P=.067). The effect of post type also failed to reach significance when controlling for patient demographics and post position in a Cox proportional hazards analysis (P=.106). However, the Cox model did show that survival was associated with tooth position (P=.003), cement (P=.021), and type of restoration (P<.001).

CONCLUSIONS

Analysis showed no evidence that post-and-core survival was significantly associated with 3 types of post-and-cores (custom-fabricated metal, prefabricated metal, and prefabricated fiber-reinforced composite resin). The percentage of root in the bone, tooth position, cement, and type of restoration, however, were significantly associated with survival.