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Objectives: This study evaluated the influence of 2% chlorhexidine digluconate (CHX) on the bond strength (BS) of a glass-fibre post to the root canal, regarding the cements (dual-cured resin or resin-modified glass-ionomer cement), the root thirds and the time of storage., Method: Eighty bovine roots were selected and endodontically treated, before being randomly assigned to the following groups according to the luting protocol: ARC (RelyX ARC); ARC+CHX; RL (RelyX Luting 2); and RL+CHX. After 24 h of luting, the roots were sliced to obtain 1 mm-thick slices. Half of each group was submitted to either 7-day or 6-month storage in artificial saliva (n=10). The specimens were subjected to push-out tests with a crosshead speed of 0.5 mm/min. The data were analysed with four-way ANOVA and Tukey's test (P≤0.05). The failure modes were analysed with a digital microscope (50× and 200×)., Results: ARC yielded a significantly higher BS compared to RL (P<0.001). Despite CHX exerted a significant effect; it depends on the interaction with the luting cement and time (P<0.001). Thus, CHX decreased the values of BS to those of ARC after 6 months (P<0.001). On the 7th day of storage, the ARC+CHX presented higher BS to the cervical and middle thirds compared to RL+CHX (P=0.012). Time solely was not a significant factor (P=0.081). Adhesive cement-dentine type and mixed failures were predominant modes for the ARC groups. For the RL groups, the main failures were adhesive cement-post and mixed modes., Conclusions: Glass-fibre posts luted with RelyX ARC dual-cure resin cement exhibited higher BS than those luted with RelyX Luting 2 resin-modified glass-ionomer cement. Furthermore, CHX was not effective to improve the BS and negatively affected the BS of RelyX ARC after 6 months of storage., Clinical Significance: The use of chlorhexidine solution seems not to improve the bond strength of fibre posts to root canals, disregarding the composition of the luting cement., (Copyright © 2014 Elsevier Ltd. All rights reserved.)

Purpose: Fiber-reinforced composite dowels have been widely used for their superior biomechanical properties; however, their preformed shape cannot fit irregularly shaped root canals. This study aimed to describe a novel computer-aided method to create a custom-made one-piece dowel-and-core based on the digitization of impressions and clinical standard crown preparations., Materials and Methods: A standard maxillary die stone model containing three prepared teeth each (maxillary lateral incisor, canine, premolar) requiring dowel restorations was made. It was then mounted on an average value articulator with the mandibular stone model to simulate natural occlusion. Impressions for each tooth were obtained using vinylpolysiloxane with a sectional dual-arch tray and digitized with an optical scanner. The dowel-and-core virtual model was created by slicing 3D dowel data from impression digitization with core data selected from a standard crown preparation database of 107 records collected from clinics and digitized. The position of the chosen digital core was manually regulated to coordinate with the adjacent teeth to fulfill the crown restorative requirements. Based on virtual models, one-piece custom dowel-and-cores for three experimental teeth were milled from a glass fiber block with computer-aided manufacturing techniques. Furthermore, two patients were treated to evaluate the practicality of this new method., Results: The one-piece glass fiber dowel-and-core made for experimental teeth fulfilled the clinical requirements for dowel restorations. Moreover, two patients were treated to validate the technique., Conclusion: This novel computer-aided method to create a custom one-piece glass fiber dowel-and-core proved to be practical and efficient., (© 2013 by the American College of Prosthodontists.)

Objective: To evaluate the impact of the type of root canal preparation, intraradicular post and mechanical cycling on the fracture strength of roots., Material and Methods: eighty human single rooted teeth were divided into 8 groups according to the instruments used for root canal preparation (manual or rotary instruments), the type of intraradicular post (fiber posts- FRC and cast post and core- CPC) and the use of mechanical cycling (MC) as follows: Manual and FRC; Manual, FRC and MC; Manual and CPC; Manual, CPC and MC; Rotary and FRC; Rotary, FRC and MC; Rotary and CPC; Rotary, CPC and MC. The filling was performed by lateral compactation. All root canals were prepared for a post with a 10 mm length, using the custom #2 bur of the glass fiber post system. For mechanical cycling, the protocol was applied as follows: an angle of incidence of 45°, 37°C, 88 N, 4 Hz, 2 million pulses. All groups were submitted to fracture strength test in a 45° device with 1 mm/ min cross-head speed until failure occurred., Results: The 3-way ANOVA showed that the root canal preparation strategy (p<0.03) and post type (p<0.0001) affected the fracture strength results, while mechanical cycling (p=0.29) did not., Conclusion: The root canal preparation strategy only influenced the root fracture strength when restoring with a fiber post and mechanical cycling, so it does not seem to be an important factor in this scenario.

Purpose: To evaluate the fracture resistance (FR) and bond strength (BS) after mechanical fatigue (MF) of flared root canals restored with different restorative techniques for fiber post cementation., Materials and Methods: The root canals of 84 single-rooted premolars were endodontically treated and prepared in order to simulate an oversized root canal, except for the positive control group (PC), in which a prefabricated fiber post (PFP) with a diameter compatible with the post cavity was cemented. In the oversized root canals, alternative restorative techniques for post cementation were tested, as follows: NC: negative control (PFP with a diameter smaller than that of the root canal); AP: PFP + accessory posts; RR: root reinforcement with composite resin; DAP: direct anatomical post; IAP: indirect anatomical post. After the luting procedures using Excite DSC and Variolink II, indirect composite crowns were cemented on composite resin cores and the specimens were mechanically fatigued (1.2 x 106 cycles, 40 N). From each group, 8 specimens were subjected to the push-out BS test and the others 6 specimens to the FR test. For both tests, the data were subjected to ANOVA and Scheffe's tests (α = 0.05)., Results: In terms of FR, all alternative techniques showed intermediate performance, being similar to both control groups. In terms of BS, only the groups DAP and IAP were similar to the well-adapted condition (positive control group)., Conclusion: The use of DAP and IAP should be the first choice for fiber post cementation in oversized root canals.

In contemporary dentistry, we have a vast range of materials to choose from, and metal free restorations have become the premier materials for achieving the ultimate in both esthetics and durability. Metal-free restorations are utilized with more conservative preparations to preserve the vital natural dentition, and have proven to be superior alternatives to traditional porcelain-fused-to-metal (PFM) restorations in many cases. There are always "pros and cons" when selecting materials, and to make the best choice it is essential for dental professionals to plan precisely and understand their options in any clinical situation. Selecting suitable materials and techniques involves consideration of the following factors: - Esthetic zone. - Required strength based on the patient's occlusion/dental habits. - Preparation reduction. - Position of the margin. - Type of restoration/preparation. - The treating clinician's philosophy. - Stump shade. Final shade. One of the most significant challenges in the metal-free dentistry is the reproduction of natural dentition without the influence of a "negative stump" - a very dark or metal core showing through the final restorations. There are many factors to be considered when working on such a case, and controlling the opacity of the coping and crown is the key to success. This article presents a unique "outside of the box" technique that provides consistent, predictable and durable restorations, which provide the best possible esthetic outcome.

Statement of Problem: The optimal luting material for fiber-reinforced posts to ensure the longevity of foundation restorations remains undetermined., Purpose: The purpose of this study was to evaluate the suitability of 3 dual-polymerizing resin cements and 2 dual-polymerizing foundation composite resins for luting fiber-reinforced posts by assessing their Knoop hardness number., Material and Methods: Five specimens of dual-polymerizing resin cements (SA Cement Automix, G-Cem LincAce, and Panavia F2.0) and 5 specimens of dual-polymerizing foundation composite resins (Clearfil DC Core Plus and Unifil Core EM) were polymerized from the top by irradiation for 40 seconds. Knoop hardness numbers were measured at depths of 0.5, 2.0, 4.0, 6.0, 8.0, and 10.0 mm at 0.5 hours and 7 days after irradiation. Data were statistically analyzed by repeated measures ANOVA, 1-way ANOVA, and the Tukey compromise post hoc test (α=.05)., Results: At both times after irradiation, the 5 resins materials showed the highest Knoop hardness numbers at the 0.5-mm depth. At 7 days after irradiation, the Knoop hardness numbers of the resin materials did not differ significantly between the 8.0-mm and 10.0-mm depths (P>.05). For all materials, the Knoop hardness numbers at 7 days after irradiation were significantly higher than those at 0.5 hours after irradiation at all depths (P<.05). At 7 days after irradiation, the Knoop hardness numbers of the 5 resin materials were found to decrease in the following order: DC Core Plus, Unifil Core EM, Panavia F2.0, SA Cement Automix, and G-Cem LincAce (P<.05)., Conclusions: The Knoop hardness number depends on the depth of the cavity, the length of time after irradiation, and the material brand. Although the Knoop hardness numbers of the 2 dual-polymerizing foundation composite resins were higher than those of the 3 dual-polymerizing resin cements, notable differences were seen among the 5 materials at all depths and at both times after irradiation., (Copyright © 2014 Editorial Council for the Journal of Prosthetic Dentistry. Published by Elsevier Inc. All rights reserved.)

Objective: This randomized controlled trial compared the survival of glass fibre and cast metal dental posts used to restore endodontically treated teeth with no remaining coronal wall., Methods: Fifty-four participants (45 women) and 72 teeth were evaluated during a follow-up period of up to 3 years. Teeth were randomly allocated to the glass-fibre and cast-metal post groups. All teeth were restored with single metal-ceramic crowns. Survival probabilities were analyzed using Kaplan-Meier statistics (p≤0.05)., Results: The 3-year recall rate was 92.3% and the survival rates of glass fibre and cast metal posts were similar (97.1% and 91.9%, respectively; p=0.682). Four failures were observed: two glass fibre posts in a premolar and anterior tooth debonded, one glass fibre post in a premolar debonded in association with root fracture, and one root fracture occurred in a molar with a cast metal post., Conclusions: Glass fibre and cast metal posts showed similar clinical performance in teeth with no remaining coronal wall after 3 years., Clinical Significance: Posts are used to restore most endodontically treated teeth with no remaining coronal wall. This randomized controlled trial, one of few to compare glass fibre and cast metal posts in such teeth, showed that post type did not significantly influence the survival of restorations. These results can help dentists respond to the important question of how best to rehabilitate endodontically treated teeth with no remaining coronal wall., (Copyright © 2014 Elsevier Ltd. All rights reserved.)

The aim of this in-vitro study was to evaluate the bond strength of fiber posts cemented in a root canal filled using various root-canal obturation techniques. A total of 33 monoradicular samples, treated endodontically, were randomly assigned to three groups according to the root-canal obturation technique: group 1, continuous-wave technique; group 2, plastic-obturator-core technique; and group 3, cross-linked gutta-percha obturator-core technique. Fiber posts were luted in each sample and each was sectioned perpendicular to the post axis. The push-out test was performed using a universal machine and the maximum failure load was recorded in MPa mm(-2) . Several samples were randomly chosen for scanning electron microscopy evaluation. The mean debris and dentinal tubule-opening scores were calculated separately in the coronal and apical portions. Bond strength was significantly higher in group 1 than in groups 2 and 3. Debris scores were significantly higher in the apical portion of groups 2 and 3 than in group 1. Within the limitations of this study it can be affirmed that thermoplasticized alpha gutta-percha seemed to worsen the cleaning of post-space walls and hence reduced fiber-post bond strength., (© 2014 Eur J Oral Sci.)

Purpose: The aim of this finite element analysis (FEA) study was to test the effect of different restorative techniques on stress distribution in roots with flared canals., Materials and Methods: Five three-dimensional (3D) FEA models that simulated a maxillary incisor with excessive structure loss and flared root canals were created and restored with the following techniques/materials: 1) a prefabricated post: 2) one main and two accessory posts; 3) i-TFC post-core (Sun Medical); 4) the thickness of the root was increased by using composite resin and the root was then restored using a prefabricated post; 5) an anatomic post was created by using composite resin and a prefabricated glass-fiber post. Composite cores and ceramic crowns were created. A 300-N static load was applied at the center of the palatal surface of the tooth to calculate stress distributions. SolidWorks/Cosmosworks structural analysis programs were used for FEA analysis., Results: The analysis of the von Mises and tensile stress values revealed that prefabricated post, accessory post, and i-TFC post systems showed similar stress distributions. They all showed high stress areas at the buccal side of the root (3.67 MPa) and in the cervical region of the root (> 3.67 MPa) as well as low stress accumulation within the post space (0 to 1 MPa). The anatomic post kept the stress within its body and directed less stress towards the remaining tooth structure., Conclusion: The creation of an anatomic post may save the remaining tooth structure in roots with flared canals by reducing the stress levels.

Aim: To evaluate ex vivo the bond strength and adaptation of fibre posts with oval and circular cross sections luted in oval canals with post spaces prepared using dedicated drills or ultrasonic tips., Methodology: Forty extracted premolars with oval canals were root filled, then randomly divided into four groups according to the post space preparation device and the shape of the luted fibre post: dedicated drill + round post, dedicated drill + oval post, ultrasonic tip + round post and ultrasonic tip + oval post. Posts were cemented with a self-adhesive cement (RelyX Unicem 2; 3M ESPE). Samples were sectioned in 1-mm-thick slices and observed under a microscope, and the area occupied by the post within the post space area was calculated. Bond strength was then measured using a push-out test, and the failure modes were evaluated with a stereomicroscope at 40× magnification. Fibre post adaptation and push-out test results were evaluated by analysis of variance (P < 0.05)., Results: Fibre posts, both round and oval, were better adapted to the apical region of the post space (P = 0.001). In oval canals, the bond strength was significantly higher in coronal regions, when the post space was prepared with a dedicated drill and an oval post was luted (P < 0.0001). Adhesive failures between cement and post were the most frequent type of failure in all groups., Conclusions: Circular and oval posts achieved similar adaptation to oval canals, but the use of ultrasonic tips and round posts resulted in reduced bond strength values., (© 2013 International Endodontic Journal. Published by John Wiley & Sons Ltd.)

Purpose: To evaluate the push-out bond strengths of prefabricated glass-fiber posts (Beijing Oya Biomaterials) with polydopamine functionalized to root dentin using two different resin cements (Paracore and RelyX Unicem) in different root regions (cervical, middle, and apical)., Materials and Methods: Forty extracted human, single-rooted teeth were endodontically treated and a 9-mm post space was prepared in each tooth with post drills provided by the manufacturer. Specimens were then randomly assigned into four groups (n = 10 per group), depending on the adhesive system and post surface treatment used: group IA (Paracore + polydopamine); group IB (Paracore + control); group IIA (RelyX Unicem + polydopamine); group IIB (RelyX Unicem + control). Following post cementation, the specimens were stored in distilled water at 37°C for 7 days. The push-out test was performed using a universal testing machine (0.5 mm/ min), and the failure modes were examined with a stereomicroscope. Data were statistically analyzed using twoway ANOVA (p = 0.05)., Results: Bond strengths (mean ± SD) were: 7.909 ± 3.166 MPa (group IA), 4.675 ± 2.170 MPa (group IB), 8.186 ± 2.766 MPa (group IIA), 4.723 ± 2.084 MPa (group IIB). The bond strength of polydopamine groups was significantly higher than one of the control groups (p < 0.0001). No significant difference was found in the micro push-out bond strengths between the two resin cement groups or the root regions (p > 0.05). Stereomicroscopic analysis showed a higher percentage of adhesive than cohesive failures in all groups., Conclusion: Surface polydopamine functionalization was confirmed to be a reliable method for improving the bond strength of resin luting agents to fiber posts. The bond strength of Paracore to fiber posts was not significantly different from that of RelyX Unicem, and considering its convenient application, Paracore can be recommended.

Statement of Problem: It is unclear how the amount of remaining coronal dentin and the type of post and core rehabilitation affect the strain, stress distribution, and fracture resistance of endodontically treated teeth., Purpose: The purpose of this study was to evaluate the effects of the type of post, type of crown, and the amount of remaining coronal dentin on the biomechanical behavior of endodontically treated teeth., Material and Methods: The investigation was conducted by using 3-dimensional finite element analysis and laboratory tests. Three-dimensional models of a maxillary central incisor were generated: without remaining coronal dentin, with 1.0 mm of remaining coronal dentin, with 2.0 mm of remaining coronal dentin, and restored with a glass-fiber post or a cast post and core in combination with a metal crown or an alumina-reinforced ceramic crown. The results were evaluated by using the von Mises criterion and Maximum Principal Stress. One hundred twenty bovine incisors were selected and divided into 12 treatment groups (n=10). Specimens were loaded at a 135-degree angle to perform strain measurements and were then loaded until fracture. The strain and fracture resistance results were analyzed with 3-way analysis of variance and the Tukey honestly significant difference test (α=.05)., Results: The alumina-reinforced ceramic crowns and metal crowns associated with a glass-fiber post showed a homogeneous stress distribution within the root. The cast post and core concentrated higher stresses at the post-dentin interface. Significant differences were found among the mean fracture resistance values for all groups (P<.05). The presence of 2.0 mm of coronal remnants resulted in lower strains and higher fracture resistance for both the metal and ceramic crowns. Roots restored with glass-fiber posts exhibited more favorable fractures., Conclusions: The presence of 2 mm of remaining coronal dentin improved the mechanical behavior of the endodontically treated maxillary incisors. Teeth restored with glass-fiber posts and composite resin cores showed a homogeneous stress distribution within the root dentin., (Copyright © 2014 Editorial Council for the Journal of Prosthetic Dentistry. Published by Elsevier Inc. All rights reserved.)

This study evaluated the microleakage of resin cements in the pulp chamber dentin. Fifty specimens of sound human molars were divided into five groups. Composite cores cemented using Clearfil SA Luting in the first group to a dried dentin and in the second group to a moistened dentin and then light-cured. In third and fourth groups, cement was placed on dried and moistened dentin and self-cured respectively. In fifth group, composite cores were cemented by Panavia F2.0. After thermocycling, microleakage was evaluated using fluid filtration technique. The highest microleakage mean value was observed in the group with light-cured to a dry dentin. The mode of curing in contrast to moisture value had significant effect on microleakage. The microleakage of self- adhesive resin cement used in this study was lower in case of self cured than in case of light-cured and was not related to the dentin surface moisture.

Aim of this study was to assess the influence of chlorhexidine digluconate (CHX) application on bond strength of glass fibre reinforced composite (FRC) posts to root dentine using adhesive luting systems. Forty extracted human mandibular premolars were endodontically treated and root canals were prepared. Teeth were divided into 2 groups according to luting system as SuperBond C&B (etch-and-rinse/chemical cure) and FuturaBond DC (self-etch/ dual cure). Each group was further divided in 2 subgroups (n=10) according to whether CHX was applied or not. Group Futura/CHX: FuturaBond DC + CHX; group Futura: FuturaBond DC; group Super/CHX: Super Bond C&B + CHX; group Super: SuperBond C&B + CHX. Mean and standard deviation (in parenthesis) values of bond strength in MPa were: group Futura/CHX: 8.86 (1.96), group Futura: 7.65 (1.01), group Super/CHX: 17.47(2.93), group Super: 12.41 (3.83). Bond strength values were affected by the type of luting agent and CHX irrigation (p=0.001, two-way ANOVA). There were statistically significant differences among the groups according to one-way ANOVA (p<0.001). Significant differences were observed in bond strength between groups Super/CHX and Super (p=0.023), between groups Futura/CHX and Super/CHX (p<0.001). Application of CHX before luting procedure with etch-and-rinse/chemical cure luting agent of glass FRC post improved long-term bond strength between glass FRC and root dentine.

This study sought to evaluate how instrumentation techniques and irrigating solutions affected the bond strength of glass fiber posts. For this study, 80 human maxillary central incisors were selected. Endodontic access was obtained, root canal length was measured, and the coronal third was prepared using Gates-Glidden drills. The specimens were embedded in acrylic resin and randomly assigned to 8 groups (n = 10): manual instrumentation only (Group 1), rotary instrumentation only (Group 2), irrigation with 2.5% sodium hypochlorite (NaOCl) (Group 3), irrigation with 2% chlorhexidine (CHX) (Group 4), manual instrumentation and irrigation with 2.5% NaOCl (Group 5), manual instrumentation and irrigation with 2% CHX (Group 6), rotary instrumentation and irrigation with 2.5% NaOCl (Group 7), and rotary instrumentation and irrigation with 2% CHX (Group 8). Specimens in Groups 5-8 also received a 1 minute final rinse with ethylenediaminetetraacetic acid. Canals were filled and the specimens stored for 30 days in distilled water. The restoration material was removed down to the apical 4 mm of the root canal. The glass fiber posts were luted with resin cement and stored for 24 hours at 37°C. Specimens were subjected to a tensile strength test at a constant speed of 1.0 mm/minute and a load of 2,000 kgf. The results were analyzed by analysis of variance and Tukey's test. Irrigation with 2.5% NaOCl reduced the bond strength of fiber posts significantly (P < 0.01), while CHX showed no effect (P > 0.05). It was concluded that irrigation with 2.5% NaOCl has a negative effect on micromechanical retention of glass fiber posts, whether manual or rotary instrumentation is used.

In this study, we evaluate the influence of post surface pre-treatments on the bond strength of four different cements to glass fiber posts. Eighty extracted human maxillary central incisors and canines were endodontically treated and standardized post spaces were prepared. Four post pre-treatments were tested: (i) no pre-treatment (NS, control), (ii) sandblasting (SA), (iii) silanization (SI) and (iv) sandblasting followed by silanization (SS). Per pre-treatment, four dual-cure resin cements were used for luting posts: DMG LUXACORE Smartmix Dual, Multilink Automix, RelyX Unicem and Panavia F2.0. All the specimens were subjected to micro push-out test. Two-way analysis of variance and Tukey post hoc tests were performed (α=0.05) to analyze the data. Bond strength was significantly affected by the type of resin cement, and bond strengths of RelyX Unicem and Panavia F2.0 to the fiber posts were significantly higher than the other cement groups. Sandblasting significantly increased the bond strength of DMG group to the fiber posts.

Purpose: To investigate the effects of pretreatment with 2% chlorhexidine in a gel base (CHX) and 100% ethanol (EtOH) on the bond strength between fiber posts relined with resin composite and root dentin under cyclic loading., Materials and Methods: Forty bovine incisor roots were divided into four groups after phosphoric acid etching: group 1 (control), irrigation with physiological saline solution; group 2, 5 min pretreatment with CHX; group 3, 1 min pretreatment with EtOH; group 4, 5 min pretreatment with CHX followed by 1 min with EtOH. Fiber posts relined with resin composite were cemented with RelyX ARC and the etch-and-rinse adhesive system Scotchbond Multi-Purpose. Each group was randomly divided into two subgroups: 24 h of storage (immediate groups) and cyclic loading (loading groups) with 250,000 cycles in a controlled chewing simulator. All roots were sectioned transversely and push-out tests were performed. Failure modes were observed and the bond strength means were analyzed using ANOVA and Tukey's test (a = 0.05)., Results: The mean values for the bond strength test (MPa) in immediate groups were: group 1, 5.44 ± 1.48; group 2, 5.57 ± 1.41; group 3, 5.49 ± 1.48; group 4, 5.57 ± 1.42. Immediate groups showed similar bond strength values (p > 0.05). In the cyclic loading groups, the bond strength values were: group 1, 2.80 ± 0.79; group 2, 4.02 (1.30); group 3, 4.50 ± 1.67; group 4, 4.97 ± 2.00. After cyclic loading, a significant decrease in the control group was observed (p < 0.05), while CHX pretreatment resulted in intermediate values (p < 0.05) and EtOH alone or associated with CHX preserved the bond strength values (p > 0.05)., Conclusion: Chlorhexidine and/or ethanol pretreatment preserved the bond strength of the fiber post after cyclic loading.

Purpose: Post and core systems are commonly used to restore endodontically treated teeth. A durable bond between fiber posts and dentin contributes to the success of the restorative treatment. Different irrigants are used during post space preparation and various studies have investigated the effects of these chemical agents on bond strength and dentin morphology., Methods: The MEDLINE-PubMed, Cochrane, and SCOPUS databases were searched for appropriate papers addressing the effects of irrigants on bonding of fiber posts to dentin and on dentin morphology. Databases were searched from 2002 through 2012. The search was performed using a variety of keywords including fiber posts, bond strength, post space preparation, post space irrigation, and smear layer removal., Results: Using multiple key words and different strategies, 68 publications were initially screened. The abstracts of these 68 publications were scanned for relevance, and 50 full-text articles were selected and read in detail. Thirty publications which discussed the effect of various intracanal irrigants on bond strengths of fiber posts and dentin morphology were incorporated in this review. Following review of all relevant papers, it can be concluded that bond strengths of fiber posts to radicular dentin can be affected by the irrigants used and that various irrigants affect different types of resin cements differently.

Aim: To evaluate effects of ageing and fatigue on the elastic modulus and short-beam shear strength of a quartz fibre/epoxy resin post material., Methodology: Cylindrical specimens (25 × 2.2 mm) were made. Elastic moduli were dynamically measured before immersion in water; after immersion in water; periodically during storage in water for up to 7 years; periodically during thermal cycling in water for up to 10 000 cycles to produce thermo-mechanical fatigue; and periodically during boiling in water for up to 100 h. After ageing, the specimens underwent short-beam shear strength testing., Results: Elastic modulus was significantly decreased by thermal cycling and by immersion in boiling water, but not by water storage. Short-beam shear strength was profoundly decreased by all three ageing processes. Short-beam shear strength was much more sensitive than elastic modulus to the ageing or fatigue processes applied in this study., Conclusions: A representative endodontic fibre post material was susceptible to a variety of ageing and fatigue processes. The effects of ageing and fatigue had a more pronounced impact on short-beam shear strength than on elastic modulus. The effects of boiling in water and thermal cycling in water were considerably larger than those of simple storage in water., (© 2013 International Endodontic Journal. Published by John Wiley & Sons Ltd.)

Purpose: To evaluate the effect of solvent removal and light-curing methods on the push-out bond strength of fiber posts to root canal dentin using a one-step self-etching adhesive., Materials and Methods: Eighty single-rooted, single-canal human mandibular premolars were used in this study. After removal of the crown, the pulp was extirpated and the post space was prepared. The teeth were divided into two main groups according to the solvent removal method, either using the paper point or the air-drying method. Each of the above main groups was further subdivided into 4 subgroups according to the light-curing method: group 1: both adhesive and resin cement were cured from the top of the post in the same step (cocuring) for 40 s; group 2: the adhesive was light cured for 20 s and the resin cement for 40 s; group 3: the adhesive was light cured for 40 s as was the resin cement; group 4: an intracanal tip was used to cure the adhesive inside the post space for 20 s. In groups 1 to 4, the solvent was evaporated using oil-free compressed air for 5 s from the root surface and excess adhesive was removed from inside the canal using a paper point. In groups 5 to 8, the adhesive and cement were applied and light cured as in groups 1 to 4, except the solvent was evaporated (air dried) from inside the post space using an intra-canal disposable plastic tip attached to the tip of a 3-way syringe. After 24 hours, three 2-mm-thick root slices were obtained from each root. Each slice was subjected to the push-out bond strength test at a crosshead speed of 0.5 mm/min. Factorial analysis (two-way ANOVA) was run to test the effect of solvent evaporation method, light-curing method, and their interactions on bond strength. One-way ANOVA followed by Duncan's Multiple Range Test were used to test the effect of lightcuring method on bond strength within each solvent evaporation method. Student's t-test was performed to compare the effect of solvent evaporation method on bond strength within each light-curing method., Results: Two-way ANOVA revealed that the solvent removal method had a significant effect on the bond strength of fiber post to root canal dentin. Neither the light-curing method nor the interaction between the two independent variables had a significant effect on the push-out bond strength., Conclusions: Only air drying the one-step self-etching adhesive could influence the bond strength of the fiber post to root canal dentin.

Purpose: To evaluate the effect of the resin cement thickness (RCT) on bond strength (BS) and gap formation (GF) of fiber posts bonded to root dentin., Materials and Methods: The roots of 24 extracted human mandibular premolars were treated endodontically and the post spaces were prepared using drills with different diameters according to the following groups (n = 8): well adapted (WA), moderately well adapted (MA) and poorly adapted (PA). The fiber glass posts were cemented (Excite DSC and Variolink II) in accordance with the manufacturer's instructions. After 1 week, the roots were transversely sectioned into six 1-mm-thick disks and photographed using an optical microscope to determine the RCT. After this, epoxy resin replicas of each sample were observed using SEM, and the mean length and width of the gaps formed in the cement/dentin/post interface were measured. Finally, each sample was subjected to the push-out test (0.5 mm/min), and the data were statistically analyzed using one-way ANOVA and Tukey's tests at the 5% level of significance., Results: The lowest RCT (μm) was observed for WA and the highest for PA. The group MA showed an intermediate value. Significantly higher push-out BS values were observed for WA compared to the other groups. The MA and PA groups were statistically similar. The highest mean gap length (%) and width (μm) were observed for PA. The groups MA and WA were statistically similar., Conclusion: Lower resin cement thickness resulted in better fiber post adhesion, that is, in higher bond strength and less gap formation.

Introduction: The aim of this study was to evaluate the influence of post system, length, and ferrule on biomechanical behavior of endodontically treated anterior teeth., Methods: The investigation was conducted by using laboratory tests and 3-dimensional finite element analysis. Eighty bovine incisors were selected and divided into 8 treatment groups (n = 10) with absence of ferrule and 2.0 mm of ferrule, restored with glass fiber post or cast post and core, and 12.0 and 7.0 mm of post length. The specimens were loaded at 135° angle, and the strain was measured by using strain gauge method. Specimens were subsequently loaded until fracture. Strain and fracture resistance results were analyzed by 3-way analysis of variance and Tukey honestly significant difference tests (α = 0.05). Three-dimensional models of a maxillary central incisor were generated with the same treatment variations used in laboratory tests. Each model was subjected to 100 N oblique loads. Results were evaluated by von Mises criterion., Results: Ferrule was a determining factor in the strain, fracture resistance, and fracture pattern. In the absence of ferrule, the use of fiberglass posts represents a conservative choice from the standpoint of the fracture patterns observed. The length of 7 mm for cast post and cores produced high rates of root fractures. Finite element analysis showed that glass fiber post showed homogeneous stress distribution, whereas cast post showed stress concentration into root canal., Conclusions: Post length influenced only the cast post strain and stress distribution. The ferrule groups always showed more satisfactory stress distribution and fracture resistance., (Copyright © 2014 American Association of Endodontists. Published by Elsevier Inc. All rights reserved.)

Statement of Problem: Endodontically treated teeth are known to have reduced structural strength. Glass fiber posts may influence fracture resistance and should be evaluated., Purpose: The purpose of this study was to evaluate the influence of glass fiber post length on the fracture resistance of endodontically treated teeth., Material and Methods: Forty intact human maxillary canines were selected and divided into 4 groups, the control group consisting of teeth restored with a custom gold cast post and core, with a length of two-thirds of the root. Other groups received prefabricated glass fiber posts in different lengths: group 1/3, removal of one-third of the sealing material (5 mm); group 1/2, removal of one-half of the sealing material (7.5 mm); and group 2/3, removal of two-thirds of the sealing material (10 mm). All the posts were cemented with resin cement, and the specimens with glass fiber posts received a composite resin core. All the specimens were restored with a metal crown and submitted to a compressive load until failure occurred. The results were evaluated by 1-way ANOVA, and the all pairwise multiple comparison procedures (Tukey honestly significantly difference test) (α=.05)., Results: The ANOVA showed significant differences among the groups (P<.002). The Tukey test showed that the control group presented significantly higher resistance to static load than the other groups (control group, 634.94 N; group 1/3, 200.01 N; group 1/2, 212.17 N; and group 2/3, 236.08 N). Although teeth restored with a cast post and core supported a higher compressive load, all of them fractured in a catastrophic manner. For teeth restored with glass fiber posts, the failure occurred at the junction between the composite resin core and the root., Conclusion: The length of glass fiber posts did not influence fracture load, but cast post and cores that extended two-thirds of the root length had significantly greater fracture resistance than glass fiber posts., (Copyright © 2014 Editorial Council for the Journal of Prosthetic Dentistry. Published by Mosby, Inc. All rights reserved.)

Objectives: To assess the influence of metallic posts in the detection of simulated vertical root fractures (VRFs) using the following imaging examinations: 2 cone beam CT (CBCT) systems [CBCT1: NewTom(®) 3G (QR Srl, Verona, Italy) and CBCT2: i-CAT Next Generation(®) (Imaging Sciences International, Hatfield, PA)] and film and digital radiographs. Additionally, the influence of the orientation of the fracture line in the detection of VRFs was evaluated., Methods: 100, human, single-rooted endodontically treated premolars were divided into 5 groups (Group 1: with posts and buccolingual VRFs, Group 2: with posts and mesiodistal VRFs, Group 3: without posts and with buccolingual VRFs, Group 4: without posts and with mesiodistal VRFs, and Group 5: with posts and without VRFs). The premolars were placed in human mandibles and imaged using the four examination modalities. The sensitivity and the specificity of each examination in the experimental groups were calculated. The data were analysed using Student's t-test., Results: The presence of metallic posts reduced the sensitivity of the CBCT1 system (p = 0.0244). Digital radiographs and the CBCT1 and CBCT2 systems had a higher sensitivity in detecting buccolingual fractures in teeth with posts, whereas film and digital radiographs had a higher sensitivity in detecting buccolingual fractures in teeth without posts (p < 0.05). The CBCT1 examination demonstrated the lowest specificity (p < 0.05)., Conclusions: The presence of metallic posts did not influence the sensitivity of most of the examinations, excluding the CBCT1 system. The fracture line orientation may influence VRF detection.

Statement of Problem: Translucent fiber posts were developed to conduct light into the root canal more effectively, thereby contributing to the polymerization of dual-polymerized resin luting agents. However, there is no consensus in the literature regarding their effectiveness., Purpose: The purpose of this study was to evaluate the tensile bond strength of fiber posts with different degrees of translucency to bovine dentin with 3 types of resin luting agents., Material and Methods: Ninety bovine roots were endodontically treated and divided into 9 groups (n=10) according to the type of post (translucent, white, and black) and resin luting agent (dual-polymerized self-adhesive; dual-polymerized + etch-and-rinse adhesive system; and autopolymerized + etch-and-rinse adhesive system). Tensile tests were performed on a universal testing machine (0.5 mm/min). To determine tensile stress, the bond area of each specimen was calculated. Data were statistically analyzed with ANOVA, Kruskal-Wallis, and Mann-Whitney tests (α=.05)., Results: Mean (standard deviation) tensile bond strength values (5.53 ± 2.29 MPa) were significantly lower for translucent posts than for white (9.51 ± 1.31 MPa) and black posts (10.12 ± 3.44 MPa) with a dual-polymerized luting agent in combination with an adhesive system (P=.012). For white (6.02 ± 1.88 MPa) and black posts (4.14 ± 0.6 MPa), the self-adhesive luting agent led to lower tensile bond strength than the dual-polymerized luting agent in combination with an adhesive system (P=.003). Irrespective of post type, the autopolymerized luting agent provided the lowest tensile bond strength (P<.001). Microscopic analysis revealed that resin luting agents adhered more to the post surface than to the root dentin., Conclusion: Post translucency did not increase the tensile bond strength of dual-polymerized resin luting agents., (Copyright © 2014 Editorial Council for the Journal of Prosthetic Dentistry. Published by Mosby, Inc. All rights reserved.)

This study aimed to evaluate the influence of mesoporous silica coating surface treatments on push-out bond strength of zirconia posts. Zirconia posts (Cosmopost) were treated with vehicle (control), sandblasting plus silane application (SB+SI), a combination of sandblasting, mesoporous silica coating and silane application (SB+MSC+SI) (n=10/group). Specimens were cemented with RelyX Unicem (3M ESPE, Germany) then horizontally segmented into three sections and subjected to a push-out test. Surface treatments showed significant higher bond strength than the control group, and SB+MSC+SI group presented higher values than SB+SI group (P<0.05). No significant differences were found in bond strength among root regions (P>0.05). We conclude that the combination of mesoporous silica coating and silane application greatly enhance the push-out bond strength of zirconia posts.

Objectives: To evaluate the effect of luting cement and thermomechanical loading on the retention of glass fibre posts in root canals., Methods: One hundred and forty-four single-rooted human premolars were endodontically treated and restored with RelyX Fibre Posts. The teeth were divided into four groups according to the cements used (Fuji I, Fuji CEM, RelyX Unicem and RelyX ARC). Each group was further divided into two subgroups according to the method of ageing (immediately tested and after thermomechanical loading). Bond strength was evaluated using a pull-out test. Microleakage was examined quantitatively with dye penetration. The dentine-cement-post bonding interface was assessed using scanning electron microscopy. Data were analysed with two-way ANOVA (pull-out test) and Kruskal-Wallis analysis (microleakage)., Results: The pull-out bond strength and microleakage were significantly affected by the type of cement and ageing. Although RelyX ARC showed the highest bond strength before thermomechanical loading (p<0.05), the sealing ability of this cement was worse than those exhibited in Fuji CEM and RelyX Unicem (p<0.05). After thermomechanical loading, pull-out strengths of Fuji I and Fuji CEM were significantly increased, whereas that of RelyX ARC group significantly decreased (p<0.05). The sealing ability of Fuji CEM was significantly better than the two resin cement groups (p<0.05) after ageing., Conclusion: Fuji CEM demonstrates increased pull-out strength after thermomechanical loading and favourable sealing ability compared with the other cements., Clinical Significance: Resin-modified glass ionomer cements have the potential benefit of achieving long-term retention when used for luting glass fibre post to root canal dentine. So it may be recommended for the cementation of glass fibre post in clinics., (Copyright © 2013 Elsevier Ltd. All rights reserved.)

Purpose: Commercial fiber-reinforced dowel systems are marketed as having better adhesion and sealing ability than conventional metallic dowel systems. The aim of this in vitro study was to evaluate the microleakage of teeth restored with nine dowel systems., Materials and Methods: Ninety mandibular second premolar teeth were decoronated, and nine homogenous groups were composed of ten teeth each. Root canal and dowel space preparations were made, and eight fiber-reinforced composite dowel systems and one stainless steel dowel system were used to fabricate dowel restorations. Microleakage measurements of the restored teeth were made with a modified fluid filtration method, and data were collected. One sample Kolmogorov-Smirnov, one-way ANOVA, and Tukey-HSD tests were performed on the relative microleakage data of the groups., Results: Microleakage values were reported relative to those for teeth with unfilled canals. The highest and lowest relative microleakage values were recorded for the metallic Parapost (7.06 × 10(-4) %) and fiber-reinforced Everstick (3.55 × 10(-4) %) groups, respectively. Significant differences in relative microleakage between the fiber-reinforced dowels and stainless steel dowels were observed. Significant differences among the fiber-reinforced dowel groups were observed as well., Conclusions: The sealing ability of all fiber-reinforced composite dowels is not better than that of stainless steel dowels, and there are significant differences among different fiber-reinforced dowel systems as well. Differences among commercial dowel systems must be taken into consideration when making a selection., (© 2013 by the American College of Prosthodontists.)

Introduction: Salivary leakage after root canal therapy is of great concern and can lead to failure of the endodontic therapy. The aim of this study was to investigate whether the use of a rubber dam (RD) during post placement impacts the success of root canal-treated teeth., Methods: Retrospective chart reviews of 185 patients with an average recall of 2.7 years were assessed for the incidence of a new periapical lesion (periapical index score >2) after root canal therapy and post placement. The patients were divided into 2 groups based on the presence or absence of an RD clamp in the verification radiograph during post placement., Results: Twenty-six patients (30 teeth) had a post placed with the use of an RD, and 159 patients (174 teeth) had a post placed without an RD. In the non-RD group, 128 (73.6%) teeth were considered successful at follow-up. In the RD group, 28 (93.3%) teeth were considered successful at follow-up. Based on the bivariate GEE model, the difference in success between these 2 groups was statistically significant (P = .035)., Conclusions: The use of an RD during prefabricated post placement provides a significantly higher success rate of root canal-treated teeth. Using an RD is already considered a standard of care for nonsurgical root canal therapy; in addition, using an RD during restorative procedures that involve open teeth should also become a standard of care., (Copyright © 2013 American Association of Endodontists. Published by Elsevier Inc. All rights reserved.)

Introduction: This in vitro study compared cone-beam computed tomography (CBCT) exam with different voxel sizes with digital periapical radiography in the detection of vertical root fractures in teeth with and without intracanal metallic posts., Methods: Eighteen single-rooted human teeth were endodontically treated, prepared for cast metal posts, and artificially fractured. After positioning the teeth in dry mandibular sockets, the samples were subjected twice (with and without posts) to digital periapical radiography at 3 different angles and to CBCT examinations with 2 voxel sizes, 0.125 and 0.25 mm. The images were evaluated by 3 oral radiologists. Indices of sensitivity, specificity, and positive and negative predictive values, in addition to the areas under the receiver operating characteristic curves (accuracy), were calculated. Comparison of the accuracy of the imaging methods was assessed by using the χ(2) test. Comparison of the accuracy between teeth with and without posts was determined by using the Fisher exact test., Results: The accuracy of the imaging methods showed no significant differences (P = .08). The comparison between teeth with and without posts in each examination revealed significant differences for CBCT with a voxel of 0.125 mm (P = .04) and for periapical radiography (P = .04)., Conclusions: No significant differences were observed between CBCT and periapical radiography in the detection of vertical root fractures, except for teeth with metallic posts in images from CBCT with a voxel of 0.125 mm and in digital periapical radiography. Furthermore, voxel size did not significantly influence the diagnosis of vertical root fractures., (Copyright © 2013 American Association of Endodontists. Published by Elsevier Inc. All rights reserved.)

Purpose: To investigate the applicability of flowable composites as post luting agents by assessing the push-out strength of posts., Methods: 36 intact single rooted human premolars were selected. The endodontic treatment was performed and half of the specimens were restored with light transmitting posts (DT Light Post Illusion) and the other half with opaque posts (Tech 21 X-OP). In both groups the following combinations of adhesive/cement were tested: OptiBond Solo Plus/Nexus Third Generation (NX3), XP Bond/SureFil SDR Flow (SDR), and Vertise Flow (VF). Push-out test was used to assess the retentive strength of fiber posts, which was expressed in megapascals (MPa). Specimens were analyzed under a stereomicroscope to determine failure mode (adhesive between luting agent and post, adhesive between luting agent and dentin or mixed failure). Push-out data and failure mode distribution were analyzed by two-way ANOVA and Chi-square test, respectively (P< 0.05)., Results: The statistical analysis revealed that only the type of luting material significantly influenced push-out bond strength of the post (P< 0.001). SDR (9.00 +/- 2.17 MPa) performed similarly to the control group NX3 (7.15 +/- 1.74 MPa), while VF (4.81 +/- 1.51 MPa) should significantly lower bond strength. Failure modes differed significantly among groups.

Crown-root fractures are one of the most challenging trauma cases to treat. Reattachment of tooth fragment to a fractured tooth being a simple procedure conserves the tooth structure, maintains the natural esthetics value and is thus considered as a favorable treatment option. The reattachment procedure using composite resin should be considered if the subgingival fracture can be exposed to provide isolation after a careful evaluation of the biologic width involvement. This case report presents a complicated crown-root fracture of permanent maxillary left central incisor, involving the biologic width in an 11-year-old boy. The traumatized tooth was treated endodontically and reinforced by using glass fiber-post. Access to the subgingival margins was gained by electro surgery. The fractured fragment was reattached using bonding system and composite resin.

The combined use of silane and solvated bonding agents on the bond strength to glass-fibre posts was investigated. A model Bis-GMA/HEMA adhesive was formulated with no solvent, 30% of ethanol or 80% of acetone. The surfaces of rectangular-shaped posts were silanated or not and one of the agents was applied, except for the control group. Cylinders of resin cement (RelyX ARC, 3M ESPE, Saint Paul, MN, USA) were built-up on the surfaces (n = 20) and submitted to shear testing. All groups showed higher bond strengths when the surfaces were silanated. When no silanization was carried out, the use of bonding agents, either solvated or non-solvated, increased the bond strengths. All groups treated with both silane and bonding agent showed higher bond strengths than the group that was only silanated. Control and ethanol-based adhesives were similar, whereas the acetone-based agent yielded higher bond strengths. Adhesive failures were predominant. Combination of silane and adhesive enhanced the bond to fibre posts., (© 2011 The Authors. Australian Endodontic Journal © 2011 Australian Society of Endodontology.)

Aim: This study aimed to compare the fracture resistance of roots filled with a bonded material, fiber posts, or titanium post systems., Methods: Canals in the first group were filled with AH Plus and gutta-percha cones, and roots in the second group were filled with Epiphany sealer and Resilon cones. The root fillings (60 roots) were removed up to 4 mm from the canal apex to obtain 10-mm-deep post spaces, and posts were cemented. The groups were as follows: AH Plus control group, Epiphany control group, AH Plus fiber post group, AH Plus titanium post group, Epiphany fiber post group, and Epiphany titanium post group. Fracture tests were performed by using an Instron testing machine. The force was applied at a 45° axial angle with a constant speed of 1 mm/min. For each sample, the force at which fracture occurred was recorded in units of newtons. Statistical analysis was carried out by using analysis of variance test., Results: There was no statistically significant difference between all groups (P > .05)., Conclusions: Titanium posts, fiber posts, and Epiphany root canal filling systems were found to have no reinforcing effect on endodontically treated roots., (Copyright © 2013 American Association of Endodontists. Published by Elsevier Inc. All rights reserved.)

Objectives: Due to morphological differences along the root canal, serious structural damage, or extensive endodontic preparation, cement thickness of luted fibre-reinforced composite (FRC) post systems can largely vary. This study aimed at evaluating the effects of a self-etch (Multilink Automix, MLA) and various self-adhesive resin cements (G-Cem, GCM; Maxcem Elite, MXE; RelyX Unicem, RLX; SmartCem 2, SMC) on the pull-out bond strengths of FRC posts to root canal dentine, and to compare the effects of different cementation thicknesses., Methods: 100 bovine incisor roots were embedded in acrylic resin and randomly assigned to two groups. Root canals of group 1 were prepared with RelyX Fiber Post drill size one (Ø 1.3mm), whereas in group 2 drill size three (Ø 1.9mm) was used to attain different cement thicknesses (thicknesses 1 and 2). Each group was then subdivided into five subgroups (n=10). RelyX Fiber Posts size one (Ø 0.70mm) were luted with the respective resin cements. All specimens were subjected to pull-out evaluation using a universal testing machine. Post surface areas covered with cement were measured by means of stereomicroscopy., Results: RLX revealed the significantly highest pull-out bond strengths in both groups (p<0.05), while MXE exhibited the significantly lowest pull-out bond strengths in group 2 (p<0.05). Main failure modes were determined as adhesive at the cement-post surface for all examined groups (except for SMC, group 2)., Conclusions: The different resin cements influenced the pull-out bond strengths, whereas the cement thickness itself was not responsible for any differences., Clinical Significance: Self-adhesive resin cements can provide an acceptable retention of FRC posts even in case of use with wider post space conditions., (Copyright © 2013 Elsevier Ltd. All rights reserved.)

The aim of this in vitro study was to evaluate the tensile strength of glass fiber posts submitted to different surface treatments. Forty-eight maxillary canines had their crowns sectioned and root canals endodontically treated. The roots were embedded in acrylic resin and distributed into 3 groups according to the surface treatment: Group I: the posts were treated with silane agent for 30 s and adhesive; Group II: the posts were cleaned with alcohol before treatment with silane agent and adhesive; Group III: the posts were submitted to conditioning with 37% phosphoric acid for 30 s before treatment with silane agent and adhesive. Each group was divided into 2 subgroups for adhesive polymerization or not before insertion into the canal: A - adhesive was not light cured and B - adhesive was light cured. All posts were cemented with Panavia F and the samples were subjected to tensile strength test in a universal testing machine at crosshead speed of 1 mm/min. Data were submitted to one-way ANOVA and Tukey's test at 5% significance level. There was statistically significant difference (p<0.01) only between group GIII-B and groups GI-A and GI-B. No significant difference was found among the other groups (p>0.05). It was concluded that the products used for cleaning the posts influenced the retention regardless of adhesive light curing.

Introduction: This study investigated the influence of clinical experience in relation to the efficacy and effectiveness of removal of 2 different fiber posts., Methods: In total, 48 intact single-rooted teeth were treated endodontically and obturated. Then, 10-mm post spaces were prepared, and fiber posts were luted. Twenty-four #1 D.T. Light-Posts were used in group 1, and 24 #2 Hi-Rem Prosthetic Posts were used in group 2. A pullout test (n = 8 per group) was performed by using a universal testing machine to compare bond strength. Then, fiber post removal efficacy and efficiency were tested. Each group was divided into 2 subgroups (n = 8) according to operator experience. In group 1, fiber posts were removed with an ultrasonic handpiece by using a #3 Start-X tip. In group 2, a size 25/0.04 ProFile was used to remove the central soft polymer macrofiber, and a #2 Largo drill was used to remove the fiber post and luting cement remnants. Post removal times were recorded to evaluate efficacy. Weight change was determined, and post space walls were analyzed microscopically to evaluate effectiveness., Results: Bond strength did not differ significantly (P = .7569) between post systems. Post hoc Tukey tests indicated that removal time was affected significantly by operator experience in group 1 (P < .001) but not in group 2. Weight change was affected significantly by experience level in both groups. No difference in post space wall characteristics was observed between subgroups., Conclusions: The Hi-Rem post was easier to remove than the D.T Light-Post., (Copyright © 2013 American Association of Endodontists. Published by Elsevier Inc. All rights reserved.)

Introduction: The purpose of this study was to determine and compare the times needed to dislodge prefabricated titanium posts of different luting lengths with various cements., Methods: Eighty-one intact extracted, single-canal human teeth were selected and endodontically treated. Specimens were randomly divided into 9 groups, which were arranged according to the post space length (5, 7, and 9 mm) and cement type (zinc phosphate, glass ionomer, and resin cement). Titanium posts were cemented into the post spaces, and after 1 week of storage they were subjected to ultrasonic vibration. The dislodging times were recorded and analyzed by using the Kruskal-Wallis and Mann-Whitney tests (P < .05)., Results: A significant difference was observed between the dislodging times on the basis of post length and luting agent (P < .001). There were also significant differences between different cements luted with the same length posts (P < .001). Significant differences were observed between the 5-mm posts and both the 7- and 9-mm posts for each cement, but the differences between the 7-mm and 9-mm posts were not significant (P < .05)., Conclusions: Changes in the cement type and post length alter the time required to dislodge a post with an ultrasonic device., (Copyright © 2013 American Association of Endodontists. Published by Elsevier Inc. All rights reserved.)

Statement of Problem: The choice of restorative method is commonly based on the cavity configuration and the residual number of cavity walls. However, the residual wall thickness could be a valuable clinical parameter in the choice of restoration for endodontically treated teeth., Purpose: The fracture resistance of endodontically treated premolars was compared with different wall thicknesses restored with direct composite resin with and without cuspal coverage and with and without fiber post insertion., Material and Methods: This study included 104 intact human maxillary premolars extracted for periodontal or orthodontic reasons. Standardized mesio-occluso-distal cavities were prepared with different palatal wall thicknesses (1.5, 2, and 2.5 mm) and a buccal wall thickness of 2 mm. Teeth were restored with or without a fiber post and with or without cuspal coverage. Specimens were subjected to thermocycling (3000 cycles, 5 to 55°C) and embedded in polymerized acrylic resin. Teeth were submitted to cyclic fatigue followed by a static fatigue test with a universal testing machine; a compressive force was applied 30 degrees to the long axis of the teeth until fracture. The results were statistically analyzed by 3-way ANOVA (α=.05)., Results: Residual wall thickness (P=.004), the type of adhesive restoration (P<.001), and fiber post insertion (P<.001) significantly influenced the fracture resistance of endodontically treated premolars., Conclusions: In specimens with a cavity wall thickness >2 mm, direct intracuspal composite resin restorations supported by a fiber post achieved comparable fracture resistance. With a residual wall thickness <2 mm, only cuspal coverage with or without a fiber post provided satisfactory fracture resistance., (Copyright © 2013 Editorial Council for the Journal of Prosthetic Dentistry. Published by Mosby, Inc. All rights reserved.)

Intraradicular posts are useful adjuncts in the restoration of endodontically treated teeth. These systems have undergone a significant evolution in recent years, and fiber-reinforced systems have started to be incorporated into routine clinical care more frequently. Despite the high number of laboratory studies pertaining to the characteristics of fiber posts, clinical studies evaluating their general success rates are rather limited. Since clinical investigations are reliable means to achieve information about the general behavior pattern of materials or techniques, assessment of this data will be beneficial to have a better understanding of fiber-reinforced intraradicular post systems. The purpose of this paper was to make a summary of clinical studies regarding various fiber posts. A PubMed search was conducted and articles dating back to 1990 were retrieved. The paper provides an overview of clinical studies on fiber posts specifically in the last decade as well as commentary analysis.

Introduction: This study examined a clinically feasible protocol for improving hydrolytic stability using a 2-step silanization including a nonorganofunctional silane., Methods: The surfaces of 24 D.T. Light-Posts (Bisco Inc, Schaumburg, IL) were polished and assigned to the following 4 groups: M: 1-step silanization with Monobond-S (MS) (Ivoclar Vivadent, Schaan, Liechtenstein); BM: 2-step silanization with 5% 1,2-bis(triethoxysilyl)ethane and then MS; and HM and HBM: 1-step and 2-step silanization, respectively, after 24% H2O2 etching. Four resin composite cylinders (RelyX Unicem; 3M ESPE, St Paul, MN) were bonded on each surface according to a microshear testing protocol. All bonded samples were stored in water at 37°C for 24 hours, and half of them were then thermocycled 5000 times before microshear testing (n = 12). The failure modes were evaluated under an optical and scanning electron microscope. Water contact angles were measured on the post surfaces before and after silanization to estimate surface hydrophobicity. The results were statistically analyzed using 2-way analysis of variance and the Tukey test., Results: The bond strengths for the BM and HBM groups were significantly higher than the M and HM groups at 5000 thermocycles (P < .05), whereas no significant differences were found between the 4 groups before thermocycling (P > .05). All debonded samples showed some fractured fibers. No significant difference in the hydrophobicity was found between the 1-step and 2-step silanized post surfaces (P > .05)., Conclusions: The 2-step 1,2-bis(triethoxysilyl)ethane/MS treatment has potential as a silanization procedure for enhancing the hydrolytic stability of the fiber post/resin composite interface., (Copyright © 2013 American Association of Endodontists. Published by Elsevier Inc. All rights reserved.)

Statement of Problem: Periodontally compromised teeth (PCT) that serve as terminal abutments (TAs) are often challenging depending on the post-and-core treatment, the type of partial fixed dental prosthesis (PFDP), and the periodontal support., Purpose: The purpose of this study was to investigate the biomechanical impact of 3 types of PFDP supported by cast post-and-cores on PCT serving as terminal abutments., Material and Methods: A 3-dimensional (3D) model of a human mandible was fabricated by using computed tomography (CT) images and parameterized in a computer-aided design (CAD) environment as follows: Right premolar preparation geometries were designed. The second premolar was assembled with 7-mm or 10-mm cast post-and-core models. Both premolar-models were designed to support single, splinted, or 1-unit cantilever splinted crowns. In each situation, their periodontium geometries were designed to be reduced by 10%, 50%, and 70%. All models were imported into a 3D finite element analysis (FEA) environment and loaded; von Mises stress values and distribution patterns were evaluated., Results: Insertion of the post primarily affected the apical areas of both the root and post; the type of PFDP and periodontal support mainly affected stress distribution. In patients with a normal periodontium, splinting the teeth did not contribute to their stress relief. By extending the post length, a stressful area close to the apex of the post was developed. Splinting mitigated the stress field of the coronal part of the 50% PCT (up to 98.9%); the 30% PCT experienced a substantial decrease (up to 215.9%) in stress in the radical part as well. The increase in the length of the post produced negligible stress-related differences in the apical part of the 50% PCT (0.2% to 2.6%). The use of the 7-mm post effectively relieved the radical part of the splinted 30% PCT. The magnitude of the stress on the radical part of post-restored PCT was considerably increased in the presence of a cantilever., Conclusions: Splinted crowns supported by a 7-mm cast post-and-core are a favorable biomechanical approach for the restoration of PCT with severe loss of coronal structure. The use of a cantilever greatly aggravates the biomechanical response, especially of post-restored PCT., (Copyright © 2013 The Editorial Council of the Journal of Prosthetic Dentistry. Published by Mosby, Inc. All rights reserved.)

Statement of Problem: Fiber posts can fail because of loss of retention; and it is unknown which luting agent provides the highest bond strength., Purpose: The purpose of this study was to investigate the tensile bond strength of glass fiber posts luted to premolar teeth with 6 resin composite luting agents., Material and Methods: Ninety-six single-rooted extracted human mandibular premolars were sectioned 2 mm coronal to the most incisal point of the cementoenamel junction. Root canals were instrumented and obturated with laterally condensed gutta percha and root canal sealer (AH26). Gutta percha was removed from the canals to a depth of 8 mm and diameter post spaces with a 1.5 mm were prepared. The specimens were divided into the following 6 groups according to the luting agent used (n=16): Group V, Variolink II; Group A, RelyX ARC; Group N, Multilink N; Group U, RelyX Unicem; Group P, ParaCore; Group F, MultiCore Flow. Each specimen was secured in a universal testing machine and a separating load was applied at a rate of 0.5 mm/min. The forces required to dislodge the posts were recorded. A 1-way analysis of variance (ANOVA) was applied to the mean retentive strengths of various cement materials (α=.05)., Results: Significant differences were recorded among the 6 cement types (P<.001). Three materials provided statistically equivalent mean bond strengths (RelyX Unicem, Paracore, and MultiCore Flow) that were significantly greater than for the other 3 materials., Conclusions: Fiber posts luted with RelyX Unicem, Paracore, and MultiCore Flow demonstrated significantly higher bond strengths., (Copyright © 2013 The Editorial Council of the Journal of Prosthetic Dentistry. Published by Mosby, Inc. All rights reserved.)

Data Sources: Medline, the Cochrane Controlled Trials Register, China National Knowledge Infrastructure and China Biology Medicine disc were searched., Study Selection: Only randomised studies were included., Data Extraction and Synthesis: Data were independently extracted. Standardised mean differences were combined and analysed using meta-analysis., Results: Thirteen studies were included; premolars were used as specimens in six studies, central incisors in five studies and canines in three articles. There was considerable variation in both alloy and fibre materials used between studies. The standardised mean difference of the combined data was 0.64 (95% confidence interval, 0.08-1.20; P < .001), indicating that the cast post group displayed significantly higher fracture resistance than the fibre post group., Conclusions: On the basis of the current best available evidence, we concluded that cast posts had higher fracture resistance than fibre posts.

Objectives: The purpose was to assess the influence of ferrule effect and length of cast post and cores, and FRC posts on the strength of anterior teeth., Materials and Methods: The investigations were conducted by means of finite element analysis with the application of contact elements. Thirteen 3D models of maxillary first incisors were generated: model 1 was an intact tooth; 2A - a tooth with all-ceramic crown with ferrule effect, 2B-D a teeth restored with, ferrule and FRC posts of various lengths 13mm, 8mm, 4mm, 3A - a tooth with ceramic crown without, ferrule effect, 3B and C teeth without ferrule and 10mm, 5mm length FRC posts, 4B-D teeth with ferrule, restored by cast posts and cores of 13mm, 8mm, 4mm lengths and 5B and C teeth without ferrule, restored with cast posts and cores of 10mm, 5mm lengths. Each model was subject to a load with a total force of 100N uniformly distributed under the lingual cingulum, at an angle of 130°. To evaluate, the strength of tooth tissues, ceramics and composites, the modified von Mises failure criterion was used, for FRC the Tsai-Wu criterion and for cast NiCr alloy the von Mises criterion. Contact stresses were calculated at the luting cement-tissue interface., Results: Ferrule effect in teeth reduces mvM stresses in dentin, in posts and in luting cement. The contact tensile stresses around posts in teeth with ferrule effect were 1.7-3.0 times smaller than in, teeth without ferrule. Lower mvM stresses occurred in teeth with cast posts in comparison with FRC posts. The mvM stresses in teeth with posts of various lengths were similar, irrespective of post material., Significance: Ferrule effect in teeth with posts and cores has a critical influence on stress reduction. Using posts and cores made of rigid materials leads to stress reduction in teeth. Post length has a small, effect on stress values in tooth structures., (Copyright © 2013 Academy of Dental Materials. Published by Elsevier Ltd. All rights reserved.)

Aim: To assess the immediate influence of dentine bonding systems (DBS) associated with 2% chlorhexidine digluconate (CHX) on glass-fibre post-bond strength to root dentine, in terms of coronal, middle and apical thirds., Methodology: Sixty bovine roots were root filled and randomly assigned to 1 of 6 groups (n = 10): SBMP (3-step etch-and-rinse system, Scotchbond Multi-Purpose), SB (2-step etch-and-rinse system, Single Bond 2), SE (2-step self-etching system, Clearfil SE Bond) and SBMP-CHX, SB-CHX and SE-CHX, respectively, associated with CHX. For all groups, a glass-fibre post was luted with a dual-cure resin cement, RelyX ARC. After 7-day storage, specimens were subjected to the push-out test. Failure modes were analysed under optical microscopy (40x). Bond strength values were statistically analysed by two-way anova and Bonferroni tests (P < 0.05)., Results: The effect of DBS was significant (P < 0.05), and SE reached higher bond strength in comparison with the other DBS tested. CHX association did not show improvement with any DBS (P > 0.05); rather, it negatively affected SE, which was detected for all thirds. There was no difference between thirds (P > 0.05), except for the SE-CHX, which presented lower values for the apical third (P < 0.05). Adhesive cement/dentine adhesive failure was predominant for all groups. CHX did not influence the failure mode for any DBS (P > 0.05)., Conclusions: The performance of the dentine bonding systems was material dependent. CHX did not improve immediate bond strength; however, CHX negatively affected the bond strength of the self-etching system, especially in the third apical., (© 2013 International Endodontic Journal. Published by John Wiley & Sons Ltd.)

This study describes how periodontology, endodontology, and dentistry were integrated for the coronal reconstruction of anterior teeth extensively destroyed by dental trauma. A 15-year-old girl suffered a bicycle accident that resulted in the fracture of teeth No. 8 and 9. Clinical and radiographic examinations confirmed coronal fracture in both teeth, in addition to compromised pulp vitality, invasion of the biologic periodontal space, and loss of coronal space due to mesialization of the neighboring teeth. The protocol consisted of endodontic treatment for the fractured teeth, periodontal surgery to augment the clinical crown and gingival recontouring, intracanal cementation of esthetic glass fiber posts, and coronal reconstruction with resin composite. At a longitudinal follow-up visit 1 year later, clinical and radiographic examinations revealed successful rehabilitation of the fractured teeth.

Statement of Problem: Since the introduction of glass fiber posts, irreversible vertical root fractures have become a rare occurrence; however, adhesive failure has become the primary failure mode., Purpose: The purpose of this study was to evaluate the push-out bond strength of glass fiber posts cemented with different luting agents on 3 segments of the root., Material and Methods: Eighty human maxillary canines with similar root lengths were randomly divided into 8 groups (n=10) according to the cement assessed (Rely X luting, Luting and Lining, Ketac Cem, Rely X ARC, Biscem, Duo-link, Rely X U100, and Variolink II). After standardized post space preparation, the root dentin was pretreated for dual-polymerizing resin cements and untreated for the other cements. The mixed luting cement paste was inserted into post spaces with a spiral file and applied to the post surface that was seated into the canal. After 7 days, the teeth were sectioned perpendicular to their long axis into 1-mm-thick sections. The push-out test was performed at a speed of 0.5 mm/min until extrusion of the post occurred. The results were evaluated by 2-way ANOVA and the all pairwise multiple comparison procedures (Tukey test) (α=.05)., Results: ANOVA showed that the type of interaction between cement and root location significantly influenced the push-out strength (P<.05). The highest push-out strength results with root location were obtained with Luting and Lining (S3) (19.5 ±4.9 MPa), Ketac Cem (S2) (18.6 ±5.5 MPa), and Luting and Lining (S1) (18.0 ±7.6 MPa). The lowest mean values were recorded with Variolink II (S1) (4.6 ±4.0 MPa), Variolink II (S2) (1.6 ±1.5 MPa), and Rely X ARC (S3) (0.9 ±1.1 MPa)., Conclusions: Self-adhesive cements and glass ionomer cements showed significantly higher values compared to dual-polymerizing resin cements. In all root segments, dual-polymerizing resin cements provided significantly lower bond strength. Significant differences among root segments were found only for Duo-link cement., (Copyright © 2013 The Editorial Council of the Journal of Prosthetic Dentistry. Published by Mosby, Inc. All rights reserved.)