• Restorative Dentistry and Endodontics
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• v.46 no.4
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• pp.50.1-50.8
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• 2021

Although several techniques have been proposed to remove fiber-reinforced composite (FRC) post, no safe and efficient technique has been established. Recently, a guided endodontics technique has been introduced in cases of pulp canal obliteration. This study describes 2 cases of FRC post removal from maxillary anterior teeth using this guided endodontics technique with a dental operating microscope. Optically scanned data set from plaster cast model was superimposed with the data set of cone-beam computed tomography. By implant planning software, the path of a guide drill was selected. Based on them, a customized stent was fabricated and utilized to remove the FRC post. Employing guided endodontics, the FRC post was removed quickly and safely with minimizing the loss of the remaining tooth structure. The guided endodontics was a useful option for FRC post removal.

• Journal of Dental Rehabilitation and Applied Science
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• v.32 no.1
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• pp.24-31
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• 2016

Purpose: Many studies have shown that airborne-particle abrasion of fiber post can improve the bonding strength to resin cement. But, airborne-particle abrasion may influence the property of fiber post. The purpose of this study is to evaluate the influence of airborne-particle abrasion on flexural strength of fiber post. Materials and Methods: Two fiber-reinforced posts; DT Light Post Size 2 (1.8 mm diameter, Bisco Inc) and RelyX Fiber Post Size 3 (1.9 mm diameter, 3M ESPE); were used in this study. Each group was divided into 3 subgroups according to different surface treatments; without pretreatment: $50{\mu}m$ aluminum oxide (Cobra$^{(R)}$, Renfert): and $30{\mu}m$ aluminum oxide modified with silica (Rocatec Soft$^{(R)}$, 3M ESPE). After airborne-particle abrasion procedure, three-point bending test was done to determine the flexural strength and flexural modulus. The diameter of each posts was measured to an accuracy of 0.01 mm using a digital micrometer. There was no diameter change before and after airborneparticle abrasion. The mean flexural moduli and flexural strengths calculated using the appropriate equations. The results were statistically analyzed using One-way ANOVA and Scheffe's post-hoc test at 95% confidencial level. Results: There was no significant difference on flexural strength between groups. Conclusion: In the limitation of this study, flexural strength and flexural modulus of fiber post are not affected by airborne-particle abrasion.

• Restorative Dentistry and Endodontics
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• v.36 no.2
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• pp.125-131
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• 2011

Objectives: The purpose of this study was to evaluate the effect of surface treatment of FRC-Post on bonding strength to resin cements. Materials and Methods: Pre-surface treated LuxaPost (DMG), Rely-X Fiber Post (3M ESPE) and self adhesive resin cement Rely-X Unicem (3M ESPE), conventional resin cement Rely-X ARC (3M ESPE), and Rely-X Ceramic Primer (3M ESPE) were used. After completing the surface treatments of the posts, posts and resin cement were placed in clear molds and photo-activation was performed. The specimens were sectioned perpendicular to the FRC-Post into 2 mm-thick segments, and push-out strength were measured. The results of bond strength value were statistically analyzed using independent samples t-test and oneway ANOVA with multiple comparisons using Scheffe's test. Results: Silanization of posts affect to the bond strength in LuxaPost, and did not affect in Rely-X Fiber Post. Rely-X ARC showed higher value than Rely-X Unicem. Conclusions: Silanization is needed to enhance the bond strength between LuxaPost and resin cements.

• Journal of Dental Rehabilitation and Applied Science
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• v.31 no.2
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• pp.75-85
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• 2015

Purpose: The purpose of this study is to evaluate which FRC-posts were more distinguishable from core. Materials and Methods: Nine extracted single-rooted mandibular premolars with similar lengths (${\pm}0.5 mm$) and widths (${\pm}0.5 mm$) were endodontically treated and obturated. One specimen which the three roots were embedded in a cold mounting resin was made. 3 specimens were made by this method. Post spaces were prepared for the following post system: FRC $Postec^{(R)}$ Plus, MACRO-$LOCK^{TM}$ POST $ILLUSION^{TM}$ $XRO^{(R)}$, $Snowpost^{(R)}$. After three different posts were placed in the roots of a specimen, each three specimens received a direct core build-up: $Luxacore^{(R)}$ Dual A3, $Luxacore^{(R)}$ Dual blue, $Filtek^{TM}$ Z350 A1E. Digital images were taken of the post and core with and without air-blowing. We asked to fifty dentists and fifty dental college students which post was more clearly discriminated from the core. Results: In surveys, when core was $Luxacore^{(R)}$ Dual blue, among three types of posts people more easily discriminated the $Snowpost^{(R)}$ from core. When core was $Luxacore^{(R)}$ Dual A3, among three types of posts people similarly more easily discriminated $Snowpost^{(R)}$ from core. When core was $Filtek^{TM}$ Z350 A1E, among three types of posts people more easily discriminated distinguished MACRO-$LOCK^{TM}$ POST $ILLUSION^{TM}$ $XRO^{(R)}$ post from core. People more easily distinguished MACRO-$LOCK^{TM}$ POST $ILLUSION^{TM}$ $XRO^{(R)}$ post from core when temperature was lowered by air-blowing. Conclusion: Ability to discriminate between FRC-post and core is different according to color contrast. MACRO-$LOCK^{TM}$ POST $ILLUSION^{TM}$ $XRO^{(R)}$ posts are more discriminable when temperature is lowered by air-blowing.

• The Journal of Korean Academy of Prosthodontics
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• v.52 no.2
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• pp.113-120
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• 2014

This study will evaluate the effectiveness of various pretreatments when fiber-reinforced composite (FRC) post is bonded to endodontically treated tooth with resin cement. Materials and methods: Canal shaping of FRC post (DT Light post, Size 3, Bisco Inc., Schaumburg, IL, USA) was performed on endodontically treated premolars at 1.5 cm from CEJ. Samples were divided into 6 groups of surface treatment after conventional washing and drying to the canal. Total of 24 FRC posts were randomly divided into 6 groups of surface treatment as follows: Group C: control - no surface treatment, Group A: airborne-particle abrasion (Cojet sand, 3M ESPE), Group S: silanization (Bis-silane, Bisco Inc.), Group M: universal primer (Monobond-plus primer, Ivoclar Vivadent Inc.), Group AS: silanization after airborne-particle abrasion, Group AM: universal primer treatment after airborne-particle abrasion. Pretreated fiber posts were cemented with resin-based luting material and photo-polymerized and cut to the thickness of 1 mm. Push-out test using a universal testing machine was performed. Bonding failure strength of post dislodgement was measured and the type of bonding failure was classified. Data were analyzed with Kruskal-Wallis test and multiple comparison groups were performed using Tukey HSD value of rank test (${\alpha}=0.05$). Results: Group AS showed significantly highest bonding strength. Group S, group AM, group A, and group M showed lower bonding strength in order. The control group showed the lowest bonding strength. Conclusion: Surface treatment with silane showed to be the most effective of the surface pretreatment methods for cementation of FRC post. Surface treatment with universal primer showed no significant difference compared with no surface treatment group as for bonding strength.

• Journal of Dental Rehabilitation and Applied Science
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• v.22 no.1
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• pp.23-27
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• 2006

This case reports describe a new approach to the use of polymers in orthodontics, using a fiber reinforced composite(FRC). FRC was successfully used in a periodontal splints, fiber post for endodontic use, orthodontic retainer and space maintainers, implant prosthesis, large span bridge, management of cracked tooth, anchorage reinforcement in orthodontics. FRC has highly favorable mechanical properties, and its strength-to-weight ratios is superior to those of most alloys. FRC has potential for use in many applications in dentistry and is expected to gain increasing application and popularity in dentistry. These case reports show that FRC is a promising anchorage reinforcement material for use in orthodontic practice.

• The Journal of Advanced Prosthodontics
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• v.5 no.2
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• pp.104-109
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• 2013

PURPOSE. Among the surface treatment methods suggested to enhance the adhesion of resin cement to fiberreinforced composite posts, conflicting results have been obtained with silanization. In this study, the effects of silanization, heat activation after silanization, on the bond strength between fiber-reinforced composite post and resin cement were determined. MATERIALS AND METHODS. Six groups (n=7) were established to evaluate two types of fiber post (FRC Postec Plus, D.T. Light Post) and three surface treatments (no treatment; air drying; drying at $38^{\circ}C$). Every specimen were bonded with dual-curing resin cement (Variolink N) and stored in distilled water for 24 hours at $37^{\circ}C$. Shear-bond strength (MPa) between the fiber post and the resin cement were measured using universal testing device. The data were analyzed with 1-way ANOVA and by multiple comparisons according to Tukey's HSD (${\alpha}$=0.05). The effect of surface treatment, fiber post type, and the interactions between these two factors were analyzed using 2-way ANOVA and independent sample T-tests. RESULTS. Silanization of the FRC Postec Plus significantly increased bond strength compared with the respective non-treated control, whereas no effect was determined for the D.T. Light Post. Heat drying the silane coupling agent on to the fiberreinforced post did not significantly improve bond strength compared to air-syringe drying. CONCLUSION. The bond strength between the fiber-reinforced post and the resin cement was significantly increased with silanization in regards to the FRC Postec Plus post. Bond strength was not significantly improved by heat activation of the silane coupling agent.

• Restorative Dentistry and Endodontics
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• v.35 no.3
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• pp.188-197
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• 2010

The purpose of this study was to compare radiopacity and radiographic discriminability of various FRC-Posts. Six FRC-Posts were investigated ; 1) FRC Postec Plus (Ivoclar Vivadent AG, Schaan, Liechtenstein), 2) Snowlight (Carbotech, Lewis center, OH, USA), 3) Dentin Post (Komet Brasseler, Lamgo, Germany), 4) Rely-X Fiber Post (3M ESPE, St.paul, MN, USA), 5) D.T.-Light Post (BISCO, Schaumburg, IL,USA), 6) Luxapost (DMG, Hamburg, Germany) The radiographs of each post with a reference 1 mm / 2 mm aluminum step-wedge was taken using digital sensor. The optical density were calculated by gray value of $10{\times}10$ pixel and compared in mm Al equivalent at five points. Six maxillary incisors of similar radiopacity were used. Radiographs of posts in Mx. incisors of lingual side of dry mandible were taken. We showed radiographs and asked the questionnaire to 3 radiologists, 3 endodontists, 3 general practitioners. The questionnaire was comprised of choices of the highest, lowest radiopaque individual post and the choices of best discriminable post at apical, coronal area. The following results were obtained. 1. Each post system showed various radiopacity. 2. There was change of discriminability between each post and simulated specimens regardless of examiner. Although each post showed various radiopacity, the difference of radiopacity did not affect on discriminability.

• Journal of the Korea Concrete Institute
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• v.14 no.6
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• pp.900-909
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• 2002

Fibers play a role to increase the tensile strength and cracking resistance of concrete structures. The post cracking behavior must be clarified to predict cracking resistance of fiber reinforced concrete. The purpose of this study is to develop a realistic analysis method for the post cracking behavior of synthetic fiber reinforced concrete members. For this purpose, the cracked section is assumed to behave as a rigid body and the pullout behavior of single fiber is employed. A probabilistic approach is used to calculate effective number of fibers across crack faces. The existing theory is compared with test data and shows good agreement. The proposed theory can be efficiently used to describe the load-deflection behavior, moment-curvature relation, load-crack width relation of synthetic fiber reinforced concrete beams.

• The korean journal of orthodontics
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• v.46 no.2
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• pp.104-110
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• 2016

Objective: Traditional retainers (both metal and fiber-reinforced composite [FRC]) have limitations, and a retainer made from more flexible ligature wires might be advantageous. We aimed to compare an experimental design with two traditional retainers. Methods: In this prospective preliminary clinical trial, 150 post-treatment patients were enrolled and randomly divided into three groups of 50 patients each to receive mandibular canine-to-canine retainers made of FRC, flexible spiral wire (FSW), and twisted wire (TW). The patients were monitored monthly. The time at which the first signs of breakage/debonding were detected was recorded. The success rates of the retainers were compared using chi-squared, Kaplan-Meier, and Cox proportional-hazard regression analyses (${\alpha}=0.05$). Results: In total, 42 patients in the FRC group, 41 in the FSW group, and 45 in the TW group completed the study. The 2-year failure rates were 35.7% in the FRC group, 26.8% in the FSW group, and 17.8% in the TW group. These rates differed insignificantly (chi-squared p = 0.167). According to the Kaplan-Meier analysis, failure occurred at 19.95 months in the FRC group, 21.37 months in the FSW group, and 22.36 months in the TW group. The differences between the survival rates in the three groups were not significant (Cox regression p = 0.146). Conclusions: Although the failure rate of the experimental retainer was two times lower than that of the FRC retainer, the difference was not statistically significant. The experimental TW retainer was successful, and larger studies are warranted to verify these results.