In vitro evaluation of glass fiber post

An Evaluation of the Fracture Resistance of Endodontically Treated Teeth Restored With Two Types of Posts (Diamond Posts and Fiber Posts): An In Vitro Study

OBJECTIVES

The aim of this study is to compare the fracture resistance and the mode of failure of endodontically treated permanent mandibular premolars restored with two types of posts: diamond posts and glass-fiber posts.

MATERIALS AND METHODS

Forty human mandibular premolars indicated for orthodontic extraction were collected for this study and were similar in shape, size, and length. The teeth were sectioned horizontally, 1 mm above the cementoenamel junction. Root canal treatment was carried out on all specimens, and obturation was done by lateral condensation. The teeth were randomly divided into two groups. The post space was prepared in the first group to receive the diamond posts and in the second group to receive the fiber posts. A dual-cure resin material was used for cementing the posts and building up the cores. Then, they were subjected to a compressive load at a cross-head speed of 1 mm per minute and at an angle of 135 degrees to the long axis of the tooth until a fracture occurred using a universal testing machine. Fracture resistance and the mode of failure were assessed. The fracture above the acrylic block level was considered favorable, and the fracture below the acrylic block level was considered unfavorable. The data were analyzed statistically. The statistical analysis of fracture resistance between the two groups was carried out with a t-test. The statistical analysis for the failure mode of the teeth was carried out with a chi-square test.

RESULTS

There was a statistically significant difference showing that the diamond posts had better fracture resistance when compared with glass-fiber posts, while there was no statistically significant difference in terms of the failure mode between the two posts.

CONCLUSION

Within the limitations of this study, it can be concluded that diamond posts showed higher fracture resistance than glass-fiber posts. Glass-fiber posts showed more favorable failure modes but were statistically insignificant compared to diamond posts.

Assessment of the Push-Out Bond Strength for Glass Fiber Posts After Different Surface Treatments: An In Vitro Study

AIM

The goal of the study was to assess the push-out bond strength of the glass fibre post after different surface treatments.

MATERIALS AND METHODS

For the purpose of the investigation, 40 mandibular premolars were chosen. After gaining access, the biomechanical preparation was completed using the step-back approach up to a size 40K file, and the canals were sealed using gutta-percha cones and the lateral condensation procedure with AH Plus sealer (epoxide-amine resin pulp canal sealer). Peeso reamers were used to remove the canal fillings, leaving 5mm of gutta-percha apically. Drills included in the package were used to prepare the post spaces so that the posts would fit in their respective post slots. These were attached to self-curing acrylic resin blocks. Fibre posts were split into four groupings of n = 10 each for surface treatment, i.e., control, hydrogen fluoride, sandblasting, and hydrogen peroxide. The cementation of posts was done by utilising dual-cure resin cement. Two millimetres of the anatomical crown were removed from each sample. Each sample's 1-mm cervical segment was taken utilising the isotope from the remaining coronal area. To perform a push-out test, at the rate of 0.5mm/min of the crosshead, every sample was inserted into a universal testing device. Each post's dislodge force from the pre-set post spacing was measured. Statistics were utilised to analyse the data.

RESULTS

Strongest bonds were made by silanization, followed by sandblasting (p value=0.002). The weakest bonds were made by the control group.

CONCLUSION

The ultimate deduction was that when glass fibre posts underwent various types of surface treatments followed by silanization, it had a significant impact on increasing their strength.

The effect of 400 nm femtosecond laser and Zn(II)chlorin e6 methyl ester (Zn(II)e6Me) photosensitizer on disinfection of radicular dentin bonded to glass fiber post

AIM

To assess and compare push-out bond strength (PBS) when canal disinfected with 5.25% NaOCl, 400 nm femtosecond laser, and natural PS activated by PDT (CP and Zn (II) Ce6 methyl ester) on bond efficacy of radicular dentin bonded to glass fiber post.

MATERIAL AND METHODS

A sum of 40 non-traumatic, cautiously extracted with closed apex human mandibular premolars were collected and decoronated up to the cement-o-enamel junction. Canals of all specimens were cleaned and shaped using a Protaper universal NiTi system via a crown-down approach, then finally dried out and obturated with gutta-percha. Post alignment space was formed with peso reamers and sanitized. Then samples were randomly allocated into four groups as per the radicular dentin designated disinfection protocols. Group 1 disinfected with curcumin photosensitizer + EDTA, group 2: 5.25% NaOCl and EDTA, group 3: Zn (II) Ce6 methyl ester and EDTA and group 4 sanitized with 400 nm fs-laser + EDTA. GFP was cemented into the radicular canal space and specimens were placed in a thermocycler. Segmentation of the root was done at three levels (coronal, middle, and apical) and positioned in a universal testing machine for PBS analysis. Failure mode analysis was performed using a stereomicroscope and statistical analysis was executed by one-way ANOVA and Tukey multiple comparison tests at a statistically significant level of p < 0.05.

RESULTS

The highest PBS was revealed by group 2 canal disinfected with 5.25% NaOCl +17% EDTA (control) at coronal (9.49 ± 1.42 MPa) and middle (7.545 ± 0.15 MPa) root levels. Whereas, the lowest PBS was displayed by group 3: Zn (II) Ce6 methyl ester +17% EDTA at coronal (6.31 ± 0.54 MPa) middle (4.85 ± 0.11 MPa) root levels respectively. Intergroup comparison presented that radicular dentin disinfected with 400 nm femtosecond laser + 17% EDTA substantiated comparable PBS result to group 2 (control) at all three root levels (p > 0.05). Likewise, root surface disinfection with Curcumin activated by PDT+17% EDTA unveiled no statistically significant result for specimens disinfected with Zn(II) Ce6 methyl ester +17% EDTA(p > 0.05). Furthermore, apical root segments in all groups showed a substantial decrease in PBS value and were comparable (p > 0.05).

CONCLUSION

The bond efficacy of glass fiber post to radicular dentin disinfected with 400 nm femtosecond laser has the potential to be used as an alternative to conventional sodium hypochlorite.

Glass fiber post resistance to dislodgement from radicular dentin after using contemporary and conventional methods of disinfection

AIM

The present study aimed to assess the bond integrity of curcumin photosensitizer (CPS) Photodynamic therapy (PDT) on fiber post disinfection bonded to radicular dentin in comparison to the conventional fiber post sterilant used.

MATERIALS AND METHODS

Fifty human permanent single-rooted premolars were utilized with the crown part sectioned using up to the cementoenamel junction. Root canal preparation was performed followed by canal obturation with gutta-percha (GP) and resin-based sealer. The post space was prepared using peso reamers leaving 4 mm at the apical part of the post space. Fifty glass fiber posts (GFP) were divided into five groups based on the surface disinfectant (n = 10). group 1: Autoclave sterilization (AS) group 2: chlorhexidine digluconate (CHX dig), group 3: CPS solution, group 4: 35% phosphoric acid (PA) gel, and group 5: No disinfection. Cementation was performed using dual-cure self-etch resin cement. Each tooth was sectioned and placed on the universal testing machine. Failure mode was analyzed using a stereomicroscope at 40x magnification. Statistical analysis was performed using one-way analysis of variance (ANOVA) and Tukey multiple comparison tests. (p = 0.05).

RESULTS

Intragroup comparison analysis demonstrated that group 2 in which 2% CHX dig was used as a post-surface disinfectant revealed the highest bond integrity at all three levels. Group 5 where no disinfectant was used to decontaminate the post surface exhibited the lowest bond values. In all the investigated groups, PBS values showed a downward trend from coronal to the apical third of the post space. Group 1 in which AS was used to sterilize the fiber post and group 3 in which CPS was smeared to decontaminate the GFPs surface-displayed comparable outcomes of PBS to group 5 specimens at all three levels. (p > 0.05).

CONCLUSION

CHX dig and PA post-surface disinfection displayed a positive impact on bond strength with the radicular dentin. However, CPS and AS do not reveal any effect on the PBS when used for post-decontamination.

High Performance Composites Based on Highly Filled Glass Fiber-Reinforced Polybenzoxazine for Post Application

Glass fiber post based on the new polymeric material, polybenzoxazine, is prepared and the effects of glass fiber contents on mechanical and thermal properties are evaluated. The mechanical response to externally applied loads of tooth restored with glass fiber-reinforced polybenzoxazine composite posts is also simulated by finite element analysis of a tridimensional model and compared with the response to that of a natural tooth. The reinforcing of glass fiber can help improve the mechanical and thermal properties of the polybenzoxazine influenced by the interfacial adhesion between the glass fiber and polybenzoxazine matrix, except for the relatively high mechanical property of the glass fiber. The mechanical data, i.e., elastic modulus under flexure load or flexural modulus by three-point bending test of the glass fiber-reinforced polybenzoxazine composites are agreed with the elastic modulus of dentin and then used in the finite element model. The restoration using the glass fiber-reinforced polybenzoxazine composite post provided the maximum von Mises equivalent stress at the cervical third area of the endodontically treated tooth model as similarly observed in the natural tooth. In addition, the maximum von Mises equivalent stress of the tooth restored with the glass fiber-reinforced polybenzoxazine composite post is also quietly like that of the natural tooth. The finding of this work provided the essential properties of the glass fiber-reinforced polybenzoxazine composite for dental restorations and appliances.

Role of Riboflavin; Curcumin photosensitizers and Ozone when used as canal disinfectant on Push-out bond strength of glass fibre post to radicular dentin

AIM

To assess the efficacy of photosensitizers (CP, riboflavin) and gaseous ozone in comparison to the conventional radicular dentin disinfectant (NaOCl) on push-out bond strength (PBS) of PFRC post cemented to radicular dentin MATERIAL AND METHOD: Human single-rooted teeth were collected, steriled implanted in polyvinyl pipes up to a cement-o-enamel junction and de coronated. Cleaning and shaping of the canal were performed using the crown down technique followed by obturation of the canal space. Canal space was prepared using peso reamers and samples were divided into four groups based on types of canal disinfectant protocols. Group 1: Riboflavin+ 17%EDTA; group 2: Curcumin Photosensitizer + 17% EDTA; group 3: Gaseous Ozone disinfection (O3) +17% EDTA and group 4 control 2.5% NaOCl +17% EDTA. Within the canal space, fiber post was cemented and cured, and thermocycled. PBS was evaluated using a Universal testing machine (UTM) and failure modes using a stereomicroscope at 40x magnification. One-way analysis of variance (ANOVA) was used to determine the mean and standard deviation of push-out bond strength (PBS). The Tukey multiple comparison tests (p = 0.05) was used to compare the means of PBS RESULTS: The highest PBS was displayed in group 2 CP+ 17% EDTA at all three root levels, coronal (8.81±0.61), middle (7.77±0.55), and apical (5.25±0.61). The lowest PBS was revealed in group 4, disinfected with 2.5% NaOCl +17% EDTA (control) at coronal (6.12±0.54), middle (5.46±0.84), and apical (3.00±1.88) levels. The most prevailed fracture mode was an adhesive failure (cement-dentin interface).

CONCLUSION

Radicular dentin disinfected with PDT using CP, riboflavin, and O3 displayed similar PBS at all root segments. NaOCl is a convenient, traditional, and commonly used disinfectant, and it's effects on PBS is still controversial.

Photodynamic therapy and other pretreatment methods on epoxy-based glass fiber post on the push-out bond strength to radicular dentin

AIM

To assess the push-out bond strength (PBS) of glass fiber post (GFP) conditioned using different surface treatment regimens bonded to radicular dentin MATERIAL AND METHODS: Sixty central incisors and canine were collected and disinfected. Decoronation following working length was determined using K-file. Rotary file system was used for cleaning and shaping. Canals of all samples were dried with paper points and obturated with gutta percha. Canal space was prepared with peso reamers. Now samples were randomly allocated into six groups based on pretreatment of GFP. Post in group 1 treated with 9% HFA+ Silane, post in group 2 surface treated with silane only, Post in group 3 surface treated with airborne particle (50 µm), group 4 post conditioned with photodynamic therapy (PDT), group 5 post pretreatment was performed with MBP and in group 6 GFP was not treated. Conditioned and non-conditioned posts were positioned in canal space and cemented. Tooth were sectioned coronally, middle and apically. Sections were positioned in universal testing machine (UTM) and debonded surfaces were evaluated for failure modes. The means and standard deviations of PBS were examined using one-way analysis of variance (ANOVA).

RESULTS

Coronal third of group 3 in which posts were sandblasted using airborne Al₂O₃ particle presented the highest PBS (11.21±0.64 MPa). Whereas, an apical section of group 4 in which posts were treated with PDT exhibited the lowest bond integrity.

CONCLUSION

Sandblasting using airborne particles (50 µm) and hydrogen peroxide (H₃PO₄) conditioned with GFP exhibited significantly higher bond strength as compared to the control. However, PDT decreases the PBS of fiber post with the root dentin.

Retention of Provisional Intraradicular Retainers Using Fiberglass Pins

Objectives:

The purpose of this study was to compare the retention properties between fiberglass pins with chemically activated acrylic resin and metallic intraradicular retainers often used for the purpose of temporary prosthetic retention.

Materials and Methods:

Two mechanical tests, pushout and traction, were performed on specimens distributed in three groups (n = 10) for each test; two metal pins G1: Metalpin Ângelus and G2: Provisional Pivot Jon in addition to one fiberglass pin G3: Whitepost DC-E, FGM. One-way analysis of variance (ANOVA) followed by Tukey’s post hoc test was used at the level of significance α = 0.05.

Results:

The fiberglass pins (G3) showed higher values in the traction test than the metal pins (G1 and G2) with a statistically significant difference (P < 0.05); however, they performed similarly to the metal pin groups in the pushout test (P > 0.05). They also presented a lower occurrence of failure in the relining acrylic resin.

Conclusion:

The study pointed out the use of fiberglass pins as suitable alternatives for provisional intracanal metallic retainers.

Comprehensive micro-mechanical characterization of experimental direct core build-up resin composites with different amounts of filler contents

Dual-cured resin-based composites are gaining popularity as core build-up materials. Physical and elastoplastic characteristics of new experimental core build-up materials with variable filler contents (+2.5 and +5 wt%) were investigated using classic macroexperiments and nanoindentation. Flexural fracture strength increased from 91.7±11.8 to 114.1±9.1 and 116.6±14.7 MPa in the +2.5 and +5 wt% groups, respectively; similarly, elastic moduli increased from 12.6±0.9 to 15.4±1.2 and 15.3±2.0 MPa, respectively. Fracture toughness increased from 1.82±0.60 to 2.28±0.53 and 2.67±0.88 MPa•m^1/2 for the +2.5 and +5 wt% groups, respectively; indentation hardness increased significantly from 0.45±0.03 to 0.55±0.04 and 0.60±0.10 GPa, respectively. The addition of +5 wt% filler content led to a mechanically superior material; the addition of +2.5 wt% filler led to better reliability.

Fracture Resistance of Endodontically Treated Anterior Teeth Restored with Different Post Systems: An In Vitro Study

Objective:

This in vitro study aimed to evaluate the fracture resistance of endodontically treated maxillary central incisors with different post systems.

Methods:

Fifty-six extracted intact maxillary permanent central incisors were used, treated endodontically (except for the control group), and distributed into the following seven test groups (n=8) depending on the post type: UHT (control group: root-filled teeth without endodontic post), ZRP (prefabricated zirconia post), GFP (prefabricated glass fiber post), CFP (prefabricated carbon fiber post), CPC (custom-made cast post and core), TIP (prefabricated titanium post), and MIP (prefabricated mixed post). The specimens were loaded in a universal testing machine until fracture occurrence. Failure loads were then analyzed with one-way analysis of variance (ANOVA), followed by multiple comparisons by using Tukey’s honest significant difference test (α=0.05).

Results:

Mean (SD) failure loads for groups ranged from 524±73.2 N for CPC to 764.1±156 N for GFP. One-way ANOVA showed significant differences in terms of fracture resistances among groups (P<0.001). Tukey’s honest significant difference test showed significant differences in fracture resistance within groups (P≤0.05), whereas no difference was observed between the UHT (control group) and CFP and CPC groups (P≥0.05).

Conclusion:

Endodontically treated teeth restored with zirconia post, glass fiber post, titanium post, or mixed post were more resistant to fracture loads compared with those that were not restored (control group) or restored with either carbon fiber post or cast post and core.

Bond performance of "Touch and Cure" adhesives on resin core systems

The purpose of this study was to compare the micro-tensile bond strength (µTBS) of three resin core composites to dentin and to examine the bonded interface of the composites. One experimental TDK-03(TD) and, two commercial, DC core Automix One (DC) and Unifil core EM(UN) were used. Flat dentin surfaces of human molars were exposed using #600 SiC paper and bonded with the respective adhesive of each system. After bonding, the composites were built up on the surfaces and cured under two conditions: "light condition" or "dark condition". µTBSs (MPa) in the light condition were: TD; 60.02±17.08, DC; 38.21±13.70, and UN; 29.50±9.71; in the dark condition: TD; 54.62±17.11, DC; 8.40±4.81, and UN; 9.47±6.56. Dark curing negatively affected the bond strength of the two commercial resin-core materials. The experimental material was not affected by the curing conditions.

Comparison of compressive strength among three different intracanal post materials in primary anterior teeth: An in vitro study

Objective:

The objective of our study was to compare the fracture resistance and the mode of failure among three different post materials in primary anterior teeth.

Materials and Methods:

A total of sixty extracted primary anterior teeth were selected for the study. The samples were divided into three groups of twenty teeth each: Group I (Ribbond), Group II (Omega loop), and Group III (Glass fiber post). Pulp therapy was followed by intracanal post and crown buildup. The samples were mounted in self-cure acrylic and subjected to compressive strength test using universal testing machine (Instron). The maximum force at which the tooth fractured was recorded.

Results:

The values were subjected to one-way analysis of variance. The mean compressive strength values of Ribbond, omega loop, and glass fiber post were found to be 83.25 N, 61.60 N, and 75.55 N, respectively. The P value was found to be 0.220.

Conclusion:

Group I (Ribbond) showed the highest fracture resistance values followed by Group III (Glass fiber post) and Group II (Omega loop). Although there is difference in mean values, they were nonsignificant.

Effect of Intracanal Post Space Treatments on Push-Out Bond Strength of Fiber Posts to Root Dentin

OBJECTIVES

The main disadvantage of fiber posts is their low bond strength to root canal wall. The aim of the present study was to assess the effect of different root canal post space treatments on push-out bond strength of fiber posts to root canal dentin.

MATERIALS AND METHODS

After post space preparation in 40 endodontically treated human premolars, the teeth were randomly divided into four experimental groups: Group 1: control group, group 2: Endsolv R, group 3: ultrasonic cleaning, group 4: Clearfil Repair. Afterwards, the posts were bonded with Panavia F 2.0 bonding cement. The bond strength of fiber posts to root canal wall in the middle part of canal was evaluated following thermocycling using push-out test. Data were analyzed using one-way ANOVA and Tamhane's multiple comparisons test. The failure mode of each group was determined under a stereomicroscope.

RESULTS

There was a significant difference in the mean push-out bond strength among the groups (P<0.05). The lowest bond strength was noted in the control group. The control group had significant differences with ultrasonic and Clearfil Repair groups (P<0.05). The bond strength of Endsolv R group increased; however, it was not significant (P>0.05).

CONCLUSIONS

It seems that ultrasonic cleaning and Clearfil Repair can modify the root canal wall and significantly increase the bond strength of fiber posts.

Comparative evaluation of fracture resistance of glass fiber reinforced, carbon, and quartz post in endodontically treated teeth: An in-vitro study

Aim and Objectives:

Use of posts improves the physical properties of endodontically-treated teeth. Different post types are developed such as metal, custom-made, carbon, and quartz. The present study was conducted to evaluate the fracture resistance of glass fiber-reinforced, carbon, and quartz post in endodontically-treated teeth.

Materials and Methods:

Forty extracted human maxillary incisor teeth were decoronated and endodontically treated and equally divided into 4 groups; control, glass fiber-reinforced, carbon, and quartz posts. No post was used in the control group. Post space was prepared and cemented with different posts and subjected to universal testing machine to check fracture resistance. The data were statistically analyzed using t-test and analysis of variance to compare the mean difference between groups (SPSS version 20, IBM).

Results:

Quartz type of endodontic post showed good fracture resistance compared to carbon and resin-reinforced post. Least resistance was observed in the control group without post.

Conclusion:

Quartz, carbon, and glass fiber-reinforced posts show good resistance to fracture, and hence can be used in endodontically-treated teeth to enhance their strength.