Fracture Resistance of Roots Restored with Four Different Fiber-Reinforced Composite Posts

Effect of Various Surface Treatments on the Push-Out Bond Strength of Fiber Posts to Root Dentin

Background This study aimed to evaluate the effect of various surface treatments on the push-out bond strength of fiber posts to root dentin. Methodology A total of 96 single-rooted premolars were decoronated and obturated and post spaces were prepared for 9 mm. The canals were irrigated with 17% ethylenediaminetetraacetic acid followed by distilled water. The samples were divided into the two following groups based on the type of fiber posts used: Group I - glass fiber post (Reforpost size 1) and Group II: quartz fiber post (Quartzix Added Posts number 1). Further, each group was divided into four subgroups based on the surface treatments (A: no treatment (control); B: silanization; C: 4% titanium tetrafluoride (four minutes) followed by silanization; D: sandblasting followed by silanization). After surface treatments, posts were cemented using self-adhesive resin cement (RelyX U200). Three 2 mm thick slices were obtained and push-out tests were done. Failure modes were analyzed under a stereomicroscope. The surface morphology of the posts was analyzed with a scanning electron microscope. Data were analyzed using a one-way analysis of variance. Results Treating the posts with airborne particle abrasion (sandblasting) followed by silanization showed the highest bond strength. The coronal level of the root showed the highest bond strength compared to the middle and apical levels. Adhesive failures between the resin cement and dentin were found to be the highest. Conclusions Sandblasting followed by silanization produced the highest bond strength. The coronal level of the root showed the highest bond strength. Adhesive failures were the highest followed by mixed failures.

Fracture resistance and stress distribution of weakened teeth reinforced with a bundled glass fiber-reinforced resin post

OBJECTIVES

To make an in vitro assessment of fracture resistance of weakened and non-weakened teeth receiving intraradicular reinforcement using Rebilda bundled glass fiber-reinforced composite posts (GT), Rebilda conventional glass fiber posts (RP), or both systems combined (GT + RP).

MATERIALS AND METHODS

Eighty sound bovine incisors were prepared and divided randomly into eight groups as follows: (a) nWnR: without simulating weakness, and without intraradicular reinforcement; (b) WnR: simulating weakness, but without intraradicular reinforcement; (c) nWGT: without simulating weakness, but with GT; (d) WGT: simulating weakness, and with GT; (e) nWRP: without simulating weakness, but with RP; (f) WRP: simulating weakness, and with RP; (g) nWGTRP: without simulating weakness, but with GT + RP; (h) WGTRP: simulating weakness, and with GT + RP. The specimens were subjected to the load-to-fracture test using the DL-2000MF universal testing machine. The finite element method assessed the mechanical behavior and stress distribution in endodontically treated teeth.

RESULTS

The groups nWGTRP and WGTRP presented the best results in the load-to-fracture test, with the former being better than the latter, but with no statistically significant difference (P > 0.05). However, there was a significant difference between these and the other groups (P < 0.05), except for nWRP. Stress distribution inside the canal wall was different among the groups, with promising mechanical behavior for nWGTRP and nWRP.

CONCLUSIONS

The Rebilda conventional fiber post (RP), combined with the Rebilda bundled glass fiber-reinforced composite post (GT) improves the resistance and stress distribution of immature teeth.

CLINICAL RELEVANCE

Longitudinal fracture is less frequent in teeth restored with GT and RP posts.

The Effect of Intraradicular Multiple Fiber and Cast Posts on the Fracture Resistance of Endodontically Treated Teeth with Wide Root Canals

Introduction

The endodontically treated teeth (ETT) with thin remaining radicular dentin thickness are predisposed to fracture; hence it requires the diligent selection and the execution of endodontic post treatment. The objective of the study was to evaluate the reinforcing effect of both multiple fiber reinforced composite (FRC) and Ni-Cr cast metal posts at anterior and posterior regions.

Material and Methods

Forty recently extracted root canal treated canine and single rooted premolar teeth were used for the study. They were randomly divided into four groups (n=10) as: Group 1, single FRC post; Group 2, multiple FRC posts; Group 3, single Ni-Cr metal post, Group 4, multiple Ni-Cr posts. The posts were cemented with self-adhesive resin cement and subsequently restored with full veneer metal crown. The compressive static load at 130⁰ for canine and 45⁰ for premolar was applied with the cross-head speed of 0.5mm/minute until the fracture. The obtained data was analyzed using the Kruskal–Wallis and Pairwise comparison tests with SPSS.

Results

The results indicate that multiple FRC post restored canine had the maximum fracture load (1843.80±7.13 N), followed by cast multiple posts (1648.99±26.84 N), single fiber post (1623±40.31 N), and cast metal single post (1493±27.33 N). A similar trend was observed in premolar with higher max fracture load with multiple FRC posts at 1920.86±20.61 N and multiple cast metal posts at 1735.43±6.05 N.

Conclusion

The restoration of ETT with larger canals by multiple FRC and metal posts provides substantially higher fracture resistance in comparison to wider single post.

Comparing marginal microleakage of three different dental materials in veneer restoration using a stereomicroscope: an in vitro study

Objectives:

The objectives were to evaluate the degree of dye penetration of three different dental materials as esthetic veneer restorations on anterior teeth using stereomicroscope, and to provide reference for clinical choice.

Materials and Methods:

Sixty freshly extracted human maxillary central incisors were selected and randomly divided into three main groups of 20 each. Respectively, the teeth were prepared for veneer restoration by fiber-reinforced composite (FRC) (Everstick NET, Stick Tech), porcelain laminate veneer (PLV) (IPS Empress II(E-Max Press)) and 3M composites (3M ESPE) bonding with G-Cem resin cement (GC). After exposed to thermocycling (500cycles per day (5–55 °C, intervals: 30 s)) and immersed in 2% basic fuchsin dye solution for 24 h, the specimens were then sectioned buccolingual into three halves in a vertical plane parallel and measured dye penetration using stereomicroscope (Zeiss). The data collected was recorded by the dye penetration index (0–5) and statistically analysed using one-way analysis of variance (ANOVA) and T-tests using SPSS 13.

Results:

It is evident that the FRC group showed the lowest mean score of 0.333 mm, and the PLV group showed a highest mean score of 0.749 mm, as compared with the FRC group and the 3M composites group. Overall, when the three groups were compared for microleakage using ANOVA, there was significant difference among the groups.

Conclusions:

To evaluate the dye penetration of microleakage, the FRC showed a better marginal adaptability for veneer restoration. Therefore, within the limitation of this study, the use of FRC as veneer on anterior teeth can be suggested.