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Objectives: This review was undertaken to answer a controversial clinical question with high-quality evidence: When severely damaged teeth are restored, which type of post (metal or fiber) demonstrates superior clinical performance? Data sources: The meta-analysis was conducted according to the guidelines in the Cochrane handbook. Electronic databases (MEDLINE, EMBASE, CENTRAL) and gray literatures were screened up to January 2018. Only randomized controlled trials (RCTs) with follow-up of at least 3 years were included. The quality of included studies was assessed by the Cochrane Collaboration's tool. Meta-analysis compared survival, success, post debonding, and root fracture incidence of teeth restored with fiber and metal posts. The GRADE system (Grading of Recommendations, Assessment, Development and Evaluations) was used to assess the strength of the evidence. Of 1,511 records, 14 full texts were obtained. Only four RCTs with follow-up times of 3 to 7 years met the selection criteria. The methodologic quality of included RCTs was low risk of bias. Fiber posts presented significantly higher survival rates than did metal posts (RR 0.57, 95% CI: 0.33 to 0.97, P = .04), while no difference was observed in success rates, post debonding rates, or root fracture rates. The GRADE assessment indicated a high quality of evidence for survival rates and a moderate quality for success rates. Conclusion: It was concluded that fiber posts displayed higher medium- term (3 to 7 years) overall survival rates than did metal posts when used in the restoration of endodontically treated teeth with no more than two coronal walls remaining. [ABSTRACT FROM AUTHOR]

Especially the applications of fibrous composites in miniature products, dental and other medical applications require accurate data of microscale mechanics. The characterization of adhesion between single filament and picoliter-scale polymer matrix usually relies on the experiments using so-called microbond (MB) testing. The traditional MB test systems provide unitary data output (i.e., converted force) which is enigmatic in resolving the fracture parameters of multi-mode interface cracks. As a fundamental basis, the momentary reaction force and respective local strain at the location of a non-ambiguous gradient are needed for a mechanical analysis. In this paper, a monolithic compliant based structure with an integrated Fiber Bragg Grating (FBG) sensor is developed and analysed. The stiffness of the compliant structure is estimated by using mathematical and finite element (FE) models. Qualification experiments are carried out to confirm the functional performance: MB testing of synthetic (carbon and glass) and natural (flax) single filaments are successfully performed. Quasi-static and dynamic analysis of the MB testing is carried out by using the FE method to interpret the response of the compliant structure. The developed strain-sensing CBPM-FBG holder shows excellent sensitivity during the MB tests for both synthetic and natural filaments, even at a low filament diameters as low as 7 μ m , making the monolithic compliant structure the first instrument capable of force-strain data output for bonded filament-droplet specimens. [ABSTRACT FROM AUTHOR]

Purpose: To evaluate marginal quality, fracture modes, and loads-to-failure of different overlay restorations in root-canal treated molars in a laboratory setup. Materials and Methods: Thirty-two mandibular first molars were randomly assigned to four groups (n = 8): UTR= un-treated (control), RCT-COM= root canal treated (RCT)+ lab-made composite overlay, RCT-FRC= RCT+composite resin overlay with two layers of multidirectional woven glass fibers; RCT-CER: RCT+ceramic overlay. The teeth in all groups were subjected to thermocycling and mechanical loading (TCML) in a computer-controlled masticator (1,200,000 loads, 49 N, 1.7 Hz, 3000 temperature cycles of 5°C to 50°C). Marginal adaptation was evaluated before and after TCML with scanning electron microscopy at 200X at the tooth-to-luting composite (IF1) and luting composite-to restoration (1F2) interfaces. After TCML, all specimens were loaded to failure in a universal testing machine at 0.5 mm/min. Data were analyzed with ANOVA and Bonferroni correction (a = 0.05). Results: Marginal adaptation decreased from 93 ± 3.4 to 82 ± 6.5 % at IF1 after TCML (p> 0.05) but the decrease was not significant between the groups (p> 0.05). At 1F2, ceramic overlays showed about 10% lower marginal adaptation than composite overlays (p < 0.05). Loads-to-failure (in N) were as follows in descending order: RCT-FRC: 3619 ± 520; UTR: 3048 ± 905; RCT-COM: 2770 ± 457; RCT-CER 2036 ± 319. RCT-FRC showed significantly higher results than those of RCT-COM (p < 0.05) and RCT-CER (p < 0.05). Only RCT-CER showed significantly lower results than that of the control (p < 0.05). While the fractures in the UTR occurred exclusively above the cementoenamel junction (Mode 1 and Mode 2) and were rated reparable, RCT-COM and RCT-CER showed exclusively catastrophic failures in varying modes (nodes 3 to 5). Only in group RCT-FRC, half of the specimens fractured in a reparable fracture mode (modes 1 and 2) with veneering composite delamination from the glass-fiber weaver layer. Conclusion: As cusp-covering overlay restorations in root canal treated molars, composite resin overlays with and without fiber reinforcement performed similar to intact teeth with varying failure types. While intact teeth failed exclusively in reparable modes, all other restorations failed in a catastrophic manner, except half of the fiber reinforced composite group. [ABSTRACT FROM AUTHOR]

Purpose: This study evaluated the marginal adaptation, fracture modes, and loads to failure of different mesio-occlusal-distal (MOD) restorations in root canal treated molars in vitro. Materials and Methods: Forty mandibular first molars were randomly assigned to five groups (n = 8): UTR= un- treated, RCT-AM= root-canal treated (RCT)+amalgam filling; RCT-COM= RCT+direct composite resin restoration; RCT- FRC= RCT+composite resin restoration with two layers of multidirectional woven glass fibers; RCT-CER= RCT+ceramic inlay. All teeth were subjected to thermocycling and mechanical loading (TCML) in a computer-controlled masticator (1,200,000 loads, 49 N, 1.7 Hz, 3000 temperature cycles of 5°C to 50°C). Marginal adaptation was evaluated before and after TCML by scanning electron microscopy at 200X at the tooth/restoration interfaces. After TCML, all specimens were loaded to failure in a universal testing machine at 0.5 mm/min. Failure types were analyzed and scored (reparable: modes 1 and 2; catastrophic: modes 3 to 5). Data were analyzed with ANOVA and Bonferroni correction (a= 0.05). Results: Marginal adaptation decreased significantly after TCML in all groups. The highest decrease was observed in RCT-FRC (before: 89.9 ± 2.2%, after TCML: 49.8 ± 11.9%) and the lowest in RCT-CER (before TCML: 90.3 ± 2.6% after TCML 80.4 ± 9.0%). Loads to failure (in N) were in descending order as follows: UTR: 3048 ± 905; RCT-CER: 1853 ± 477; RCT-AM: 1447 ± 363; RCT-FRC: 1066 ± 306; RCT-COM 960 ± 228. While UTR resulted in statistically higher loads to failure than those of all other groups (p < 0.05), RCT-CER showed significantly higher results than those of RCT-COM (p < 0.05) and RCT-FRC (p < 0.05). The UTR group showed exclusively reparable failures in the form of either superficial (mode 1) or complete cusp chipping (mode 2), but all restored teeth exhibited catastrophic failures involving fractures along or through the restoration (modes 3 to 5). Conclusion: None of the restored teeth in any group were able to bear the same load level as the natural teeth. With regard to marginal adaptation and fracture resistance, luted ceramic inlays were advantageous. The integration of FRC in the restoration had no positive effect on the fracture resistance. FRC application showed a negative effect on marginal adaptation of composite resin restorations. [ABSTRACT FROM AUTHOR]

Purpose: The aim of this study was to evaluate in vitro the influence of fiber reinforcement and luting cement on the static failure load (SFL) and dynamic failure load (DFL) of simulated two-unit cantilever resin-bonded fixed dental prostheses (RBFDPs). Materials and Methods: Forty-six particulate filler composite (PFC) beams and 76 fiber-reinforced composite (FRC) beams were prefabricated and subsequently luted (RelyX ARC or Panavia F2.0) onto flat ground bovine enamel. The SFL of the different specimen types was determined with a peel test and the DFL was determined with a rotating cantilever beam fatigue testing device. Results: The PFC specimens showed a significantly lower SFL than the FRC specimens. The luting cement showed a significant effect on the SFL of the PFC specimens, but not with FRC. The DFL of PFC specimens was significantly lower than for FRC specimens. The luting cement showed a significant effect on the DFL of the PFC specimens, but not so with FRC. With both the SFL and the DFL tests all PFC beams fractured, leaving the bonded part on the tooth surface, but FRC beams partially debonded from the tooth surface, leaving fibers connected to the enamel surface to a varying extent. Coincidentally, the uncured fibers turned out to be prone to aging, an effect which has been investigated. Conclusion: Within the limitations of this study, it can be concluded that PFC without fiber reinforcement is not suitable for the fabrication of two-unit cantilever RBFDPs, despite the significant effect of the luting cement, but FRC is suitable. [ABSTRACT FROM AUTHOR]

Purpose: To evaluate the clinical performance of direct Class II fiber-reinforced composite restorations on nonvital teeth. Materials and Methods: Thirty patients age 18 or older were included in this clinical trial restoring 35 molars. The inclusion criteria were: two- to four-surface restorations, replacement of composite and amalgam restorations necessary or unrestored teeth with decay reaching the pulp, teeth having homogeneous root canal fillings terminating 0 to 2 mm from the radiographic apex. Teeth with residual cavity walls less than 1 mm or with complete loss of the clinical crown were excluded. Teeth were restored using a combination of Ultra etch 35% phosphoric acid, PQ1 adhesive system, and Vit-l-escence microhybrid composite resin. The enamel peripheral shell of the restoration was built up first; a resin-impregnated piece of polyethylene ribbon fiber (Ribbond Triaxial) was covered with B1 Perma-Flo flowable composite, placed into a prepared canal, folded, and light cured; then, dentin and enamel occlusal surface stratification was completed. All 35 restorations were evaluated at 6 months and 1 year by two independent evaluators using modified USPHS criteria. Results: No failure was reported and alpha scores were recorded for all parameters. Before starting the treatment, 26 out of 35 teeth (74%) had apical periodontitis as diagnosed radiographically. At the 1-year recall, no signs of periapical lesions were detected and radiographs reported neither periodontal ligament widening nor periapical radiolucency. Conclusion: Direct fiber-reinforced composite resin restorations demonstrated excellent clinical performance at 1 year. [ABSTRACT FROM AUTHOR]

Purpose: The study evaluates the behavior of different adhesive systems and resin cements in fiber post placement, with the intent to clarify the possible role of unfilled resin as a luting material for fiber posts. Materials and Methods: Two luting agents (Dual-Link and Unfilled Resin) for cementing fiber posts into root canals were applied either with All-Bond 2 or One-Step Plus, or without an adhesive system, and challenged with the pushout test. Slices of roots restored with posts were loaded until post segment extrusion in the apical-coronal direction. Failure modes were analyzed under SEM. Results: Push-out strength was significantly influenced by the luting agent (p < 0.05), but not by the bonding strategy (p > 0.05). The best results were obtained in combination with Unfilled Resin with One-Step Plus. Dual-Link groups failed mainly cohesively within the cement, while Unfilled Resin demonstrated more adhesive fracture at the post interface. Conclusion: The results of this study support the hypothesis that adhesive unfilled resin application is essential for achieving high bond strength to radicular dentin. [ABSTRACT FROM AUTHOR]

Purpose: To evaluate the effect of cyclical mechanical loading on the bond strength of a fiber and a zirconia post bonded to root dentin. Materials and Methods: Forty single-rooted human teeth (maxillary incisors and canines) were sectioned, and the root canals were prepared at 12 mm. Twenty randomly seleced specimens received a quartz fiber post (FRC) (D.T. Light-Post) and 20 others received a zirconia post (ZR) (Cosmopost). The posts were resin luted (All Bond 2 + resin cement Duo-link) and each specimen was embedded in epoxy resin inside a PVC cylinder. Ten specimens with FRC post and 10 specimens with ZR post were submitted to fatigue testing (2,000,000 cycles; load: 50 N; angle of 45 degrees; frequency: 8 Hz), while the other 20 specimens were not fatigued. Thus, 4 groups were formed: G1: FRC+0 cycles; G2: FRC+2,000,000 cycles; G3: ZR+0 cycles; G4: ZR+2,000,000 cycles. Later, the specimens were cut perpendicular to their long axis to form 2-mm-thick disk-shaped samples (4 sections/specimen), which were submitted to the push-out test (1 mm/min). The mean bond strength values (MPa) were calculated for each tooth (n = 10) and data were submitted to statistical analysis (α = 0.05). Results: Two-way ANOVA revealed that the bond strength was significantly affected by mechanical cycling (p = 0.0014) and root post (p = 0.0325). The interaction was also statistically significant (p = 0.0010). Tukey's test showed that the mechanical cycling did not affect the bonding of FRC to root dentin, while fatigue impaired the bonding of zirconium to root dentin. Conclusion: (1) The bond strength of the FRC post to root dentin was not reduced after fatigue testing, whereas the bonding of the zirconia post was significantly affected by the fatigue. (2) Cyclical mechanical loading appears to damage the bond strength of the rigid post only. [ABSTRACT FROM AUTHOR]

Purpose: (1) To evaluate the interfacial strength between FRC Postec posts and three luting agents (Multilink, Variolink II, and MultiCore Flow) following different surface treatments, and (2) to observe the effect of sandblasting (Rocatec Pre) on the surface morphology of methacrylate-based fiber posts. Materials and Methods: The posts received one of the following surface treatments: (1) sandblasting, (2) sandblasting + silanization, (3) silanization or (4) no treatment. The three luting agents were bonded to the post and the post-cement bond strength was evaluated with the microtensile test. SEM observation of sandblasted and nontreated posts was performed. Post-cement interfaces were also evaluated. Data were statistically analyzed with two-Way ANOVA with post treatment and luting agent as factors. Tukey's test was applied for post-hoc comparisons. Results: Post treatment and the interaction between type of luting agent and type of post treatment were significant factors for bond strength (p < 0.001). The type of luting agent did not significantly influence bond strength (p = 0.07). Sandblasting + silanization performed better than sandblasting or no treatment (p < 0.001). Silanization resulted in significantly higher bond strengths than no treatment (p = 0.045). No differences were detected between sandblasting + silanization and silanization. SEM observation revealed an increased surface roughness and exposure of fibers in sandblasted posts. Conclusion: Silanization was confirmed to be a reliable method for improving the bond strength of resin luting agents to fiber posts. Bond strength of resin luting agents to fiber posts was not influenced by the type of luting agent. The sandblasting procedure modified the methacrylate-based post surface texture. [ABSTRACT FROM AUTHOR]

Purpose: Fatigue resistance of post and cores is critical to the long term behavior of restored nonvital teeth. The purpose of this in vitro trial was to evaluate the influence of the post material's physical properties on the adaptation of adhesive post and core restorations after cyclic mechanical loading. Materials and Methods: Composite post and cores were made on endodontically treated deciduous bovine teeth using 3 anisotropic posts (made of carbon, quartz, or quartz-and-carbon fibers) and 3 isotropic posts (zirconium, stainless steel, titanium). Specimens were submitted to 3 successive loading phases -- 250,000 cycles at 50 N, 250,000 at 75 N, and 500,000 at 100 N -- at a rate of 1.5 Hz. Restoration adaptation was evaluated under SEM, before and during loading (margins) and after test completion (margins and internal interfaces). Six additional samples were fabricated for the characterization of interface micromorphology using confocal microscopy. Results: Mechanical loading increased the proportion of marginal gaps in all groups; carbon fiber posts presented the lowest final gap proportion (7.11%) compared to other stiffer metal-ceramic or softer fiber posts (11.0% to 19.1%). For internal adaptation, proportions of debonding between dentin and core or cement varied from 21.69% (carbon post) to 47.37% (stainless steel post). Debonding at the post-cement interface occurred only with isotropic materials. Confocal microscopy observation revealed that gaps were generally associated with an incomplete hybrid layer and reduced resin tags. Conclusion: Regardless of their rigidity, metal and ceramic isotropic posts proved less effective than fiber posts at stabilizing the post and core structure in the absence of the ferrule effect, due to the development of more interfacial defects with either composite or dentin. [ABSTRACT FROM AUTHOR]

Purpose: The aim of this study was to evaluate the influence of the operator's experience on the outcome of fiber post cementation using an etch-and-rinse acetone-based adhesive. Materials and Methods: Fifteen human anterior teeth were used in the study. One trained operator performed the endodontic procedures and prepared the roots for the insertion and cementation of the posts. At this point, teeth were divided into 3 groups and distributed to 3 operators to lute the posts: an expert operator (EO), a moderately experienced operator (ME), and an operator with a low level of experience (LE). Quartz fiber posts (DT Light Post #1 or #2, RTD) were used. Posts were cemented using Prime&Bond NT Dual Cure adhesive system (Dentsply Caulk) in combination with the dual-curing resin cement Calibra (Dentsply Caulk). The post retention was assessed with the "thin-slice" push-out test. One-way ANOVA was performed to examine the effect of the operator on push-out strength, followed by post-hoc multiple comparisons using Tukey's test, with the significance level set at α = 95%. Results: The results of push-out strength testing were as follows: EO (12.44 ± 3.63 MPa), ME (11.68 ± 2.64 MPa), LE (11.18 ± 3.12 MPa). No statistically significant differences were determined among the three groups. Conclusion: There was no statistically significant difference in the retention measured for fiber posts luted by operators with different levels of clinical experience. Given the parameters of this investigation, the level of operator experience in luting fiber posts does not affect post retention under laboratory conditions. [ABSTRACT FROM AUTHOR]

Purpose: The aim of this in vitro study was to evaluate the marginal adaptation and retention of inlay fixed partial dentures (IFPDs) made with 1 fiber-reinforced composite and 2 different ceramic materials using quantitative scanning electron microscope analysis after thermal cycling and mechanical loading, which simulated approximately 5 years of oral service. Materials and Methods: Eighteen IFPDs made with fiber-reinforced composite (SR Adoro/Vectris), zirconium oxide-TZP (Cercon), and magnesia partially stabilized zirconia (DC-Leolux) covered with silica-based ceramics were tested in this study. The specimens were mechanically loaded in the vestibular cusp of the pontic element in a computer-controlled masticator with 1,200,000 half-sinusoid mechanical cycles of maximum 49 N each at a frequency of 1.7 Hz. A total of 3,000 thermocycles at 5°C and 55°C, 2 minutes each, were performed simultaneously. The marginal adaptation was analyzed at the interface of the luting composite and the abutment inlay/onlay (CI) and at the interface of the tooth and the luting composite (TC). Results: The percentages of continuous margin at the CI interface were 94.6 ± 3.1 and 88 ± 6.7 for Adoro/Vectris, 92.9 ± 5 and 85.7 ± 6.1 for Cercon, and 96.2 ± 2.1 and 82.2 ± 9.8 for DC-Leolux, respectively, before and after loading. The percentages of continuous margin at the TC interface were 86.7 ± 6.7 and 62.5 ± 16.4 for Adoro/Vectris, 93.3 ± 3.4 and 83.2 ± 5.9 for Cercon, and 96.1 ± 2.4 and 75.3 ± 7 for DC-Leolux. Statistically significant differences were found after loading between the fiber-reinforced composite and the 2 ceramic systems at the TC interface. Conclusion: Within the limitations of this experimental study with regard to the sample size and contacting vectors, the results showed that flexibility of the framework may play an important role in the marginal adaptation of the IFPDs. More rigid materials may transfer less stress to the margins, thus promoting a more stable adhesion to the dental tissues. [ABSTRACT FROM AUTHOR]

Purpose: As polymerization shrinkage is compensated by flow of the composite, several attempts have been performed for relief of the contraction stresses. The aim of this in vitro study was to evaluate the effect of flowable composite or fiber use under composite restorations on microtensile bond strength of composite to dentin in Class I cavities or flat dentin surfaces. Materials and Methods: Twenty-four sound extracted human first or second mandibular molars were randomly assigned to two groups (Class I cavities with a high c-factor or flattened dentin surfaces with a low c-factor). The dentin surfaces were treated with adhesive resin and restored with resin composite using four different techniques (bulk; with flowable composite; with a glass fiber (everStick NET); with a polyethylene fiber [Ribbond]). After 24 h storage at 37°C in water, the specimens were thermocycled 600 times between 5 and 55°C. Microtensile test specimens with a 0.9 x 0.9 (± 0.1) mm2 cross-sectional area were produced, and bond strength tests were carried out at a crosshead speed of 1 mm/min. Mean bond strengths were analyzed using two-way ANOVA and Bonferroni's test at a 95% significance level. Results: Flowable composite decreased dentin bond strength in cavities with a high c-factor (p < 0.05). The group restored with everStick NET showed stable bond strengths regardless of the effect of c-factor. Ribbond THM used under composite restorations increased dentin bond strength in cavities with a high c-factor (p < 0.05). Conclusion: Flowable composite decreased dentin bond strength in cavities with a high c-factor; however, using a glass fiber in combination with flowable resin, stable bond strengths can be achieved in cavities with a high c-factor. Polyethylene fiber in combination with flowable resin increases the microtensile bond strength to the dentin floor in cavities with a high c-factor. [ABSTRACT FROM AUTHOR]

Summary: A maxillary central incisor with mild periodontitis and extensive loss of coronal tooth structure was endodontically treated and restored with a translucent quartz-fiber post and a composite core. Treatment was completed with the cementation of full-ceramic crowns on teeth 11 and 21. Informed consent was obtained from the patient. Due to the extent of the periodontal disease, tooth 11 was extracted two years later. With the patient's consent, the tooth was used for research. The tooth was sectioned at 11 levels perpendicularly to the long axis and investigated by means of optical microscopy and scanning electron microscope (SEM). The visual examination showed perfect adhesion between the various interfaces (restoration-dentin-post) at both the coronal and root levels. The adhesion between the post and dentin appeared to be free of gaps, and even where the composite cement showed a nonhomogeneous thickness, voids were not apparent. The tooth under examination allowed the authors to check the effectiveness of the adhesion and the integrity of the hybrid layer after exposure to the oral cavity for two years. The results of this investigation show that there were no gaps between the adhesive resin and dentin and no hydrolysis of the adhesive bond. This case suggests that it is possible to obtain good results in the short term from the cementation of quartz-fiber posts with composite resin cements. [ABSTRACT FROM AUTHOR]

Purpose: The purpose of this study was to evaluate the clinical performance of surface-retained adhesive composite fixed partial dentures reinforced by an ultra-high molecular weight polyethylene (UHMWP) fiber (Ribbond THM). Materials and Methods: Twenty-three surface-retained fiber reinforced composite (FRC) fixed partial dentures (FPD) were placed by two operators in 23 patients, each with a single missing tooth. The restorations included prefabricated composite resin pontics, and no preparations were done on the lingual surfaces of the abutment teeth. The patients were recalled for examinations every year for up to 3 years. Restorations were evaluated directly using the modified Ryge criteria. The minimum observation period was 1 year and the maximum observation period was 3 years. Results: At baseline, 23 restorations were graded as Alpha for all parameters. At one year and two years (n = 21), three Bravos for wear resistance and surface texture/gingival inflammation and two Bravos for color match were observed. Twenty-one of 23 restorations were retained at the end of two years (91.3%) and 78.3% were retained after a maximum of 3 years. Conclusion: The results of this clinical study suggest that UHMWP FRC FPDs are quite acceptable at least for three years. However, further clinical investigations are still needed for improved long-term clinical performance. [ABSTRACT FROM AUTHOR]

This article describes the rationale and method of using glass fibers reinforced with resin composite as an external (framework to reuse a patient's own natural anterior tooth as a pontic, after extraction. (Quintessence Int 2004,35-549-553) [ABSTRACT FROM AUTHOR]

Purpose: This study was undertaken to characterize the fracture resistance and mode of fracture of endodontically treated incisors restored with cast post-and-core, prefabricated stainless steel post, or carbon fiber--reinforced composite post systems. Materials and Methods: Ten endodontically treated teeth restored with each technique were subjected to a compressive load delivered at a 130-degree angle to the long axis until the first sign of failure was noted. The fracture load and the mode of fracture were recorded. Results: The failure loads registered in the three groups were not significantly different. Between 70% and 80% of teeth from any of the three groups displayed fractures that were located above the simulated bone level. Conclusion: The use of carbon fiber--reinforced composite posts did not change the fracture resistance or the failure mode of endodontically treated central incisors compared to the use of metallic posts. [ABSTRACT FROM AUTHOR]

Purpose: The aim of this study was to measure the flexural strength and the elastic modulus of composite resin with and without reinforcing fibers and to evaluate the reinforcing effect of various fibers. Materials and Methods: A polyethylene fiber (Ribbond), a polyaramid fiber (Fibreflex), and three glass fibers (FibreKor, GlasSpan, Vectris) were used to reinforce composite resins. The flexural strength and elastic modulus of specimens in the three-point bending mode were measured using a universal testing machine at a cross-head speed of 1 mm/min after storage in water at 37°C for 24 hours. All tests were carried out in a water bath at 37°C. The data were analyzed using analysis of variance and the Sheffé test at P = 0.05. After testing, the fractured surface was evaluated using a scanning electron microscope at 50, 500, and 3,000 magnifications. Results: Yield flexural strengths of nonreinforced resins were 48 to 56 MPa, and those of reinforced resins were 56 to 134 MPa. Ultimate flexural strengths of nonreinforced specimens were 96 to 119 MPa, and those of reinforced ones were 203 to 386 MPa. Elastic modulus of nonreinforced resin was 6 to 9 GPa, and fiber reinforcing increased the value to 9 to 15 GPa, while it had no effect in Ribbond. Conclusion: Most of the fibers used in this study increased both yield and ultimate flexural strengths of composite resins, with the exception of the yield strength of Vectris. GlasSpan, Fibreflex, and FibreKor were effective in reinforcing elastic modulus, while Ribbond had no effect on it. Unidirectional glass fibers and polyaramid fiber were effective in reinforcing both flexural strength and elastic modulus of composite resin. [ABSTRACT FROM AUTHOR]

Purpose: The aim of this study was to measure the flexural properties of fiber-reinforced composite (FRC) used in frameworks of fixed partial dentures. In addition, the influence of water storage on the properties was determined. Materials and Methods: Rhombic test specimens for four groups were milled from bulk FRC material DC-Tell. The test specimens of the first group were stored and tested dry. In the second group, the test specimens were water stored for 3 months at 37 ± 1°C and tested in water. The specimens of the third group were also water stored, but they were tested dry at room temperature. Water-stored test specimens of the fourth group were dehydrated and tested dry at room temperature. A three-point bending test was used to measure the flexural properties. The quantity of glass fibers in the test specimens was determined by combustion analysis. Water uptake was calculated after 3 months of water immersion. The direction and length of fibers were examined, and elemental composition was determined. Results: Water storage decreased the flexural strength by 66% and flexural modulus by 60%. After dehydration, the flexural strength did not recover to the same level as the flexural strength of the dry-group specimens. The fiber content was 38% by volume. Water uptake was 3 wt%. The reinforcement of DC-Tell was short fibers in random orientation, and the elemental composition of fibers was similar to that of E-glass. Conclusion: Water storage decreases the flexural properties of the bulk fiber-reinforced composite DC-Tell. This may restrict the use of DC-Tell as a framework of crowns and bridges in the oral cavity in the long term. [ABSTRACT FROM AUTHOR]

Bondable reinforcement ribbon can be used in dentistry to splint periodontally involved teeth, to provide postorthodontic splinting, to reinforce provisional prostheses, and to fabricate direct adhesive prostheses. Four cases illustrate esthetically and functionally successful use of reinforced ribbon. [ABSTRACT FROM AUTHOR]

Purpose: The aim of the present study was to investigate the influence of different filling materials and methods on marginal integrity in Black Class I fillings. Materials and Methods: Standardized occlusal cavities were prepared in SO extracted human molars The preparations were filled with composite resin (1), with composite resin using the incremental technique (2), an experimental glass-fiber-reinforced (3) and polyester-reinforced (4) composite resin, a direct composite inlay (5), a ceramic insert (6), a Cerafil inlay (7), and with an experimental direct filling using Dyract AP compomer (8). Allocation of the teeth to the test groups was randomized; further processing was done on a blind basis. After the preparation of replicas, the teeth were subjected to a thermomechanical cycling process of 2,000 temperature cycles (5°C/55°C) and 50,000 stress cycles (50 N). This was followed by production of a second set of replicas and quantitative margin analysis by SEM (200X). A dye penetration test was then performed on the mesiodistal section. Results: Groups 1, 2, 5, 6 and 7 displayed a good primary marginal quality, with the proportion of continuous margins reaching more than 85%. Significantly poorer results were recorded for the experimental glass-fiber-reinforced composite resins and Dyract compomer. where the proportion of perfect margins was only between 36% and 73%. In groups 1, 2, 5, 6 and 7, marginal integrity remained stable after the thermomechanical stress cycles, with the Cerafil inlays recording the best values: 89% perfect margins and 3% marginal gaps. In contrast, the experimental composite resins and the compomer underwent a significant (p < 0.05) increase in the proportion of marginal gaps and a significant (p < 0.05) reduction in the proportion of continuous margin. Conclusion: The results of This study show that neither Dyract compomer nor the glass-fiber-reinforced composite resins tested can be recommended for use in the occlusally stressed posterior region, whereas the other filling materials and methods were sufficiently stress resistant. [ABSTRACT FROM AUTHOR]

Teeth in the mandibular anterior region of the mouth, affected by years at periodontal disease and resultant bone loss, frequently require treatment to the patient to be able to chew comfortably and effectively. Often patients choose to keep compromised teeth, despite being presented with treatment options involving a fixed or removable prosthesis. In these situations, mechanical stabilization becomes necessary. Current treatment possibilities include bonding with resin composite or placement of a bonded metal mesh splint, a cast metal resin-bonded retainer, or a fiber-reinforced resin composite splint. Coupled with good oral hygiene practices, these mechanical stabilization techniques can provide increased oral comfort and improved function, especially tor geriatric dental patients. {Quintessence Int 1999:30.243-248] [ABSTRACT FROM AUTHOR]

Objective: This study was intended to quantify the marginal leakage of three glass-ionomer-resin composite hybrid materials and compare it with the leakage exhibited by a glass-ionomer cement and a bonded resin composite system. Method and materials: Standardized Class V cavities were prepared on root surfaces of 105 extracted human teeth, randomly assigned to five groups of 21 each, and restored with either Ketac-Fil Aplicap, ZWO/Scotchbond Multi-Purpose Plus, Vitremer, Photac-Fil Aplicap, or Dyract. The teeth were thermally stressed tor 500 cycles and stained with methylene blue. The microleakage was quantified spectropholometrically, and the data were statistically analyzed with Friedman's test. Results: There were no significant differences in microleakage among the live groups. Restorations of all tested materials showed some marginal leakage in Class V cavities. Conclusion: The microleakage performance of glass-ionomer-resin composite hybrid materials was similar to those of a conventional glass-ionomer and a bonded resin composite system (Quintessence Int 1999;30:117-121) [ABSTRACT FROM AUTHOR]

The article analyzes the effect of an air-polishing device on tensile bond strength of a dental sealant. As reported, the tensile bond strength of sealants prepared with various techniques was measured. It was seen that air polishing and acid etching produced the highest bond strength of all the groups tested. A significant higher mean bond strength was found after air polishing and acid etching than after no cleansing prior to acid etching. Rubber cup polishing produced lower bond strengths than air polishing and acid etching, but this was not statistically significant. Scanning electron microscopic observation of the fracture sites revealed cohesive failures for all treatment groups.

The article presents information on the observations made on the intraenamel veneers of processed composite resin used for the esthetic restoration of generalized facial stains or defects. It was found that the physical properties of these veneers are superior to chairside microfilled resins and are less technique-sensitive to operator ability. It sates that the bond strength of indirect resin veneers are not as great as that of etched porcelain veneers, because they are fabricated indirectly. However, the minimal cost, simplicity of fabrication and esthetic qualities of indirect resin veneers make them a viable alternative to other veneering systems.

Purpose: The use of reinforcing fibers in dentures has raised concerns about possible increased adherence of yeasts to the surface. The aim of this in vitro study was to compare the adherence of Candida albicans to the surface of denture-base polymer and to E-glass fibers. Materials and Methods: Test specimens were made from an autopolymerized denture-base resin (Palapress) reinforced with preimpregnated unidirectional E-glass fibers, which were exposed at the surface. The test specimens were pretreated with parotid saliva and incubated without agitation in standardized yeast suspensions (108 colony-forming units per mL) in phosphate-buffered saline at 37°C for 1 hour. The test specimens were then washed to remove nonadherent cells. After being air dried, they were sputter coated with gold-palladium for scanning electron microscopy SEM). To compare the adherence to different surfaces, the number of yeast cells found either on the polymer matrix or on the glass fibers was counted from SEM fields (170 μm × 120 μm, 600×) of randomly selected areas. Results: The mean density of yeast cells found on the surface of the polymer matrix was significantly higher (P < 0.001) than that on the surface of glass fibers. The number of adherent yeast cells found at the interface between the fibers and polymer matrix was high. Conclusion: The adherence of C albicans to E-glass fibers was lower than to polymer matrix in the denture composite. If fibers are exposed only during polishing of the composite, the reinforcing material appears not to increase the adherence of this common oral yeast. However, areas with permanently exposed fibers may provide mechanical retention for yeast cells at the interface of the components. [ABSTRACT FROM AUTHOR]

Abstract Objectives The purpose of this study was to characterize the adhesive interface formed due to the dissolving capability of 4 primer systems into pre-polymerized semi-interpenetrating polymer network (semi-IPN)-based fiber-reinforced composite (FRC) and luting cement. Materials and methods Semi-IPN FRC (everStick C&B, StickTech) prepregs stored for various durations (at 4 °C; 1, 1.5, and 3 years) were used to fabricate the specimens. FRC specimens (n = 10) were light-cured and treated with primers before adhering a luting cement onto them. Each age group was divided into four subgroups according to the primer used: no priming, a dimethacrylate adhesive primer, universal primer, and primer intended for composite surfaces. The degree of monomer conversion (DC%) of the luting cement; nanohardness, elastic modulus and structural information of the luting cement–FRC adhesive interface were measured. Results According to analysis of variance (P ≤ 0.05), no statistical difference was observed in the DC% among the tested groups. However, both universal and composite primers showed increased nanohardness in 1- and 1.5-year-aged groups. The highest nanohardness (0.55 ± 0.21 GPa) and elastic modulus (14.27 ± 5.19 GPa) were observed in specimens of 1-year-aged FRC primed with the application of universal primer. Raman spectroscopy and scanning electron microscopy examination confirmed the presence of poly(methyl methacrylate) at the interface when the FRC prepregs were aged for 3 years before use. Conclusion Both primers improved diffusion of monomers of composite luting cement into the polymerized semi-IPN polymer structure and possible covalent binding with pendant methacrylate groups in the polymer matrix of FRC. The diffusing capability of universal and composite primers might increase the opportunity to form solid adhesive interface bonding between the FRC and composite luting cement. [ABSTRACT FROM AUTHOR]

Purpose Fiber-reinforced composite (FRC) fixed dental prostheses (FDPs) have shown good performance in clinical applications due to their good mechanical properties and minimally invasive approach. However, typical failure patterns of FRC FDPs are often localized at the pontic site. That reflects the structural considerations at the framework and pontic location that need to be examined when creating these kinds of prostheses. Study selection Peer-reviewed articles and other scientific literature were reviewed for providing up-to-date information on how pontics of FRC FDPs can be made. A thorough literature search was done using PubMed and Google Scholar. Two individuals did an assessment of the articles in order to include those related to pontics and framework design of FRC FDPs. The search terms used were “fiber-reinforced dental prosthesis” and “Pontics of fiber-reinforced dental prosthesis”. Results These findings indicate that a cross-sectional fiber design, substructure and thicker pontics made of a variety of materials might reduce failures at the pontic site. Conclusions The thickness of pontics of FRC FDPs interrelated with the vertical positioning of the FRC framework influences the load-bearing capacities of prostheses of these kinds. The understanding of the factors involved in the fabrication of pontics of FRC FDPs may overcome the drawbacks identified in these prostheses, thus extending their longevity. [ABSTRACT FROM AUTHOR]

Introduction: Treatment of mechanical exposure of the pulp during caries excavation presents a clinical challenge. In this case series of 15 patients, with a follow-up period of over a year, the outcome of direct pulp capping with Biodentine (septodont) after mechanical pulp exposure was assessed.Aim Of Study: The aim of this study is to evaluate the outcome of direct pulp capping with Biodentine in deeply carious teeth when pulp was mechanically exposed during caries excavation and cavity preparation. Vital pulps exposed during caries excavation in molar teeth were treated with 3% sodium hypochlorite for 2 min. If adequate hemostasis was achieved, the pulp tissue was capped with Biodentine, which covered the entire pulpal floor. This was followed by the placement of a layer of resin-modified glass ionomer cement and a final layer of composite resin (Filtek Z350-3M) to complete the restoration. The patients were recalled periodically and evaluated for any evidence of pulpal/periapical pathology.Results: In the follow-up period that ranged from 12 to 24 months, all teeth were asymptomatic.Conclusion: Biodentine appears to be a suitable material for direct pulp capping under clinical conditions. However, long-term follow-up studies and controlled trials involving a large sample size are warranted. [ABSTRACT FROM AUTHOR]

ABSTRACT: Tetrabenzoylgermane 1 and various substituted tetrabenzoylgermanes 2–7 were investigated as visible light (VL) photoinitiators (PIs) for dental dimethacrylate resins and dimethacrylate‐based composites. The tetrabenzoylgermanes 1–7 show a very strong VL absorption between 400 and 450 nm. Substituents on the benzoyl chromophore strongly influence their properties such as melting point, solubility, absorption behavior, or PI reactivity. A good photobleaching behavior and a very high reactivity as VL PI was found in photo‐differential scanning calorimeter experiments for selected tetrabenzoylgermanes. Composite pastes containing only ∼0.1 wt % of Ge‐PI exhibited a sufficient photocuring due to the high PI‐reactivity of the tetraacylgermanes. Among the investigated germane PIs, tetrakis(2‐methylbenzoyl)germane 2 shows the best performance as VL PI for restorative composites and enables the composites to be photocured using an LED with an emission maximum of 500 nm. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2018, 135, 46115. [ABSTRACT FROM AUTHOR]

This study evaluated the influence of the cementation length of glass fiber-reinforced composite (FRC) on the fatigue resistance of bovine teeth restored with an adhesively cemented FRC. Thirty roots of single-rooted bovine teeth were allocated to 3 groups (n = 10), according to the ratio of crown length/root length (post cementation length): group 1 = 2/3, group 2 = 1/2, and group 3 = 1/1. The roots were prepared, the fiber posts (FRC Postec Plus) were cemented, and the specimens were submitted to 2 million mechanical cycles. After fatigue testing, a score was given based on the number of fatigue cycles until fracture, and data were submitted to statistical analysis. All specimens were resistant to fatigue. Taking into account the methodology and results of this study, the evaluated fiber posts can be cemented based on the ratio of crown/root at 1/1. Further clinical studies must be conducted to verify this ratio. [ABSTRACT FROM AUTHOR]

Biomechanical integrity of endodontically treated teeth (ETT) is often compromised. Degree of hard tissue loss and type of final prosthetic restoration should be carefully considered when making a treatment plan. The objective of this prospective clinical trial was to assess the influence of the type of prosthetic restoration as well as the degree of hard tissue loss on 7-y clinical performance of ETT restored with fiber posts. Two groups ( n = 60) were defined depending on the type of prosthetic restoration needed: 1) single unit porcelain-fused-to-metal (PFM) crowns (SCs) and 2) 3- to 4-unit PFM fixed dental prostheses (FDPs), with 1 healthy and 1 endodontically treated and fiber post-restored abutment. Within each group, samples were divided into 2 subgroups ( n = 30) according to the amount of residual coronal tissues after abutment buildup and final preparation: A) >50% of coronal residual structure or B) equal to or <50% of coronal residual structure. The clinical outcome was assessed based on clinical and intraoral radiographic examinations at the recalls after 6, 12, 24, 36, 48, and 84 mo. Data were analyzed by Kaplan-Meier log-rank test and Cox regression analysis ( P < 0.05). The overall 7-y survival rate of ETT restored with fiber post and either SCs or FDPs was 69.2%. The highest 84-mo survival rate was recorded in group 1A (90%), whereas teeth in group 2B exhibited the lowest performance (56.7% survival rate). The log-rank test detected statistically significant differences in survival rates among the groups ( P = 0.048). Cox regression analysis revealed that the amount of residual coronal structure ( P = 0.041; hazard ratio [HR], 2.026; 95% confidence interval [CI] for HR, 1.031-3.982) and the interaction between the type of prosthetic restoration and the amount of residual coronal structure ( P = 0.024; HR, 1.372; 95% CI for HR, 1.042-1.806) were statistically significant factors for survival ( ClinicalTrials.gov NCT01532947). [ABSTRACT FROM AUTHOR]

Background: Glass fiber-reinforced composites (FRCs) have been adapted for routine clinical use in various dental restorations and are presently also used in cranial implants. The aim of this study was to measure the load-bearing capacity and failure type of glass FRC implants during static loading with and without interconnective bars and with different fixation modes. Methods: Load-bearing capacities of 2 types of FRC implants with 4 different fixation modes were experimentally tested. The sandwich-like FRC implants were made of 2 sheets of woven FRC fabric, which consisted of silanized, woven E-glass fiber fabrics impregnated in BisGMA-TEGDMA monomer resin matrix. The space between the outer and inner surfaces was filled with glass particles. All FRC implants were tested up to a 10-mm deflection with load-bearing capacity determined at 6-mm deflection. The experimental groups were compared using non-parametric Kruskal-Wallis analysis with Steel-Dwass post hoc test. Results: FRC implants underwent elastic and plastic deformation until 6-mm deflection. The loading test did not demonstrate any protrusions of glass fibers or cut fiber even at 10-mm deflection. An elastic and plastic deformation of the implant occurred until the FRC sheets were separated from each other. In the cases of the free-standing setup (no fixation) and the fixation with 6 screws, the FRC implants with 2 interconnective bars showed a significantly higher load-bearing capacity compared with the implant without interconnective bars. Conclusions: FRC implants used in this study showed a load-bearing capacity which may provide protection for the brain after cranial bone defect reconstruction. [ABSTRACT FROM AUTHOR]

Objectives: The aim of this study was to assess the effect of artificial accelerated aging (AAA) on color change of direct and indirect fiber-reinforced composite (FRC) restorations. Materials and Methods: Direct (Z250) and indirect (Gradia) composite resins were reinforced with glass (GF) and polyethylene fibers (PF) based on the manufacturers' instructions. Forty samples were fabricated and divided into eight groups (n=5). Four groups served as experimental groups and the remaining four served as controls. Color change (ΔE) and color parameters (ΔL*, Δa*, Δb*) were read at baseline and after AAA based on the CIELAB system. Three-way ANOVA and Tukey's test were used for statistical analysis. Results: Significant differences were found in ΔE, ΔL*, Δa* and Δb* among the groups after AAA (P<0.05). Most of the studied samples demonstrated an increase in lightness and a red-yellow shift after AAA. Conclusions: The obtained ΔE values were unacceptable after AAA (ΔE≥ 3.3). All indirect samples showed a green-blue shift with a reduction in lightness except for Gradia/PF+ NuliteF. [ABSTRACT FROM AUTHOR]

Introduction: In cases of severe hard tissue loss, 2 mm circumferential ferrule is difficult to achieve which leads to incorporation of different ferrule designs. Aim: To compare and evaluate the effect of different crown ferrule designs on the fracture resistance of mandibular premolars restored with fiber posts, composite cores, and crowns. Materials and Methods: Fifty freshly extracted mandibular premolars were endodontically treated and divided into five groups: Group I - 2 mm circumferential ferrule above the cementoenamel junction (CEJ); Group II - 2 mm ferrule on the facial aspect above CEJ; Group III - 2 mm ferrule on the lingual aspect above CEJ; Group IV - 2 mm ferrule on the facial and lingual aspects above CEJ with interproximal concavities, and Group V - no ferrule (control group) and were later restored with fiber posts, composite cores, and crowns. Specimens were mounted on a universal testing machine, and compressive load was applied at a crosshead speed of 1 mm/min until fracture occurred. Results: The results showed that circumferential ferrule produced the highest mean fracture resistance and the least fracture resistance was found in the control group. Conclusion: Circumferential ferrule increases the fracture resistance of endodontically treated teeth restored with bonded post, core, and crown. [ABSTRACT FROM AUTHOR]

Objective: The aim of this in vitro study was to determine the load and deflection at failure of different lingual retainers bonded with composite to enamel in a standardized three-point bending test. The results were rationalized with finite element analysis (FEA) models. Materials and methods: Four types of multistranded wires, Dead Soft Respond, Twisted ligature, Penta-One, Gold-plated Penta-One, and two glass fibre-reinforced composite retainers, Fibre 07 and Fibre 09, were bonded to enamel with composite and submitted to a three-point bending test. The load and deflection at failure and the mode of debonding were recorded. The stiffness of the wires was determined and all experimental data were used in FEA models to rationalize the observed values and mode of debonding. Results: Significant higher load and deflection were found for the most flexible retainers Twisted ligature and Dead Soft Respond. All retainers failed between the wire and composite, which was confirmed by FEA showing the highest stress in the composite around the retainer. The FEA models showed that the amount of composite used for bonding the retainers should be 2-4mm. Conclusions: Based on the in vitro results, optimal bonding of lingual retainers can be achieved by flexible retainers, bonded with intrinsically strong composites. According to the FEA models the retainer should be bonded with 2-4mm composite, leaving the critical 'free-wire' length for the success of the retainer system. [ABSTRACT FROM AUTHOR]

Objectives: To evaluate the influence of irradiation time on degree of conversion (DC) and microhardness of high-viscosity bulk-fill resin composites in depths up to 6 mm. Materials and methods: Four bulk-fill materials (Tetric EvoCeram Bulk Fill-TECBF; x-tra fil-XF; QuixFil-QF; SonicFill-SF) and one conventional nano-hybrid resin composite (Tetric EvoCeram-TEC) were irradiated for 10, 20, or 30 s at 1,170 mW/cm. DC and Knoop microhardness (KHN) were recorded after 24-h dark storage at five depths: 0.1, 2, 4, 5, and 6 mm. Data were statistically analyzed using ANOVA and Bonferroni's post-hoc test ( α = 0.05). Results: With increasing bulk thickness, DC and KHN significantly decreased for TEC. TECBF and SF showed a significant decrease in DC and KHN at 4-mm depth after 10-s irradiation, but no decrease in DC after 30-s irradiation ( p > 0.05). XF and QF demonstrated no significant DC decrease at depths up to 6 mm after irradiation of at least 20 s. At 4-mm depth, all materials tested achieved at least 80 % of their maximum DC value, irrespective of irradiation time. However, at the same depth (4 mm), only XF and QF irradiated for 30 s achieved at least 80 % of their maximum KHN value. Conclusions: Regarding DC, the tested bulk-fill resin composites can be safely used up to at least 4-mm incremental thickness. However, with respect to hardness, only XF and QF achieved acceptable results at 4-mm depth with 30 s of irradiation. Clinical relevance: Minimum irradiation times stated by the manufacturers cannot be recommended for placement of high-viscosity bulk-fill materials in 4-mm increments. [ABSTRACT FROM AUTHOR]

Aims: To compare the clinical efficacy of two space maintainers namely, conventional band and loop and Fiber Reinforced Composite Resin (FRCR) space maintainers. Subjects and Methods: Thirty healthy children, aged 5 to 8 years were selected having at least two deciduous molars in different quadrants indicated for extraction or lost previously. FRCR space maintainer was placed in one quadrant and in the other quadrant band and loop space maintainer was cemented. All the patients were recalled at 1st, 3rd, and 6th months for evaluation of both types of space maintainer. Patient acceptability, time taken, and clinical efficacy was recorded. Statistical analysis used: The observations thus obtained were subjected to statistical analysis using Chi- square test and Mann-Whitney U test. Results: Patient acceptability was greater in Group I (FRCR) in comparison to Group II (band and loop space maintainer). The time taken by Group I was significantly lower as compared to that of Group II. In Group I, debonding of enamel, composite was the most common complication leading to failure followed by debonding of fi ber composite. In Group II, cement loss was the most common complication leading to failure followed by slippage of band and fracture of loop. The success rates of Groups I and Group II weares 63.3% and 36.7%, respectively. Conclusion: The study concluded that FRCRFiber Reinforced Composite Resin (Ribbond) space maintainers can be considered as viable alternative to the conventional band and loop space maintainers. [ABSTRACT FROM AUTHOR]

Objective: To analyze the fatigue resistance, debonding force, and failure type of fiber-reinforced composite, polyethylene ribbon-reinforced, and braided stainless steel wire lingual retainers in vitro. Methods: Roots of human mandibular central incisors were covered with silicone, mimicking the periodontal ligament, and embedded in polymethylmethacrylate. The specimens (N = 50), with two teeth each, were randomly divided into five groups (n = 10/ group) according to the retainer materials: (1) Interlig (E-glass), (2) everStick Ortho (E-glass), (3) DentaPreg Splint (S2-glass), (4) Ribbond (polyethylene), and (5) Quad Cat wire (stainless steel). After the recommended adhesive procedures, the retainers were bonded to the teeth by using flowable composite resin (Tetric Flow). The teeth were subjected to 10,00,000 cyclic loads (8 Hz, 3 -100 N, 45° angle, under 37 ± 3°C water) at their incisoproximal contact, and debonding forces were measured with a universal testing machine (1 mm/min crosshead speed). Failure sites were examined under a stereomicroscope (x40 magnification). Data were analyzed by one-way analysis of variance. Results: All the specimens survived the cyclic loading. Their mean debonding forces were not significantly different (p > 0.05). The DentaPreg Splint group (80°/o) showed the highest incidence of complete adhesive debonding, followed by the Interlig group (60%). The everStick Ortho group (80%) presented predominantly partial adhesive debonding. The Quad Cat wire group (50%) presented overlying composite detachment. Conclusions: Cyclic loading did not cause debonding. The retainers presented similar debonding forces but different failure types. Braided stainless steel wire retainers presented the most repairable failure type. [ABSTRACT FROM AUTHOR]

Purpose: The objective of this study is to evaluate the fracture strength and mode of failure of endodontically treated teeth with flared canals restored with two fiber reinforced systems (glass fiber and quartz fiber) and one base metal cast post and core system. Materials and Methods: Forty five anterior teeth were decoronated at cemento-enamel junction and were endodontically treated. Post space was prepared and randomly divided into three groups according to post system. Specimens were loaded at 45° in a universal testing machine at a cross head speed of 0.5 mm/min until failure. The mode of failure was classified as repairable or non-repairable. Results: Teeth restored with cast posts have fracture strength twice that of teeth restored with fiber posts. Fiber-reinforced posts failed at a certain compressive force but they were repairable unlike the non-repairable fracture seen with cast posts. Conclusion: The results of this study showed that, fracture strength and mode of failure in anterior teeth with flared canals varied according to the type of post used to support a crown. [ABSTRACT FROM AUTHOR]

Aim: Various alternatives to metal orthodontic archwires have produced varied successes over the years. This study sought to evaluate the bending properties of fiber-reinforced polymeric composite (FRC) archwires compared with similarly sized nickel-titanium (Ni-Ti) archwires. Methods: Two different 0.018-inch translucent FRC orthodontic wires (Translucent Archwire I and Translucent Archwire II) were tested against 0.014-, 0.016-, and 0.018-inch nonsuperelastic nickel titanium orthodontic wires. The wires in each group (n = 10) were evaluated with threepoint bending using a universal testing machine. Wire segments were deflected at midspan to 3.1 mm at a rate of 2 mm/min. Loading and unloading slope and modulus were calculated, as were force values during activation and deactivation and elastic recovery. Results: It was found that the 0.018-inch Ni-Ti archwire demonstrated the highest force values at different deflection distances followed by Translucent Archwire II, 0.016-inch Ni-Ti, Translucent Archwire I, and finally 0.014-inch Ni-Ti. 0.016-inch Ni-Ti exhibited the highest modulus value, followed by 0.018-inch Ni-Ti, 0.014-inch Ni-Ti, Translucent Archwire II, and finally Translucent Archwire I. During deactivation, the elastic recovery of 0.014-inch Ni-Ti and 0.016-inch Ni-Ti was significantly greater than Translucent Archwire II. Conclusion: The bending properties of BioMer's FRC archwires were found to be comparable to Ni-Ti, as advertised by the manufacturer. [ABSTRACT FROM AUTHOR]

Abstract: Objective: To improve its mechanical performance, structural optimization had been used in a previous study to obtain an alternative design for a 3-unit inlay-retained fiber-reinforced composite (FRC) dental bridge. In that study, an optimized layout of the FRC substructure had been proposed to minimize stresses in the veneering composite and interfacial stresses between the composite and substructure. The current work aimed to validate in vitro the improved fracture resistance of the optimized design. Methods: All samples for the 3-unit inlay-retained FRC dental bridge were made with glass-fibers (FibreKor) as the substructure, surrounded by a veneering composite (GC Gradia). Two different FRC substructure designs were prepared: a conventional (n =20) and an optimized design (n =21). The conventional design was a straight beam linking one proximal box to the other, while the optimized design was a curved beam following the lower outline of the pontic. All samples were loaded to 400N on a universal test machine (MTS 810) with a loading speed of 0.2mm/min. During loading, the force and displacement were recorded. Meanwhile, a two-channel acoustic emission (AE) system was used to monitor the development of cracks during loading. Results: The load–displacement curves of the two groups displayed significant differences. For the conventional design, there were numerous drops in load corresponding to local damage of the sample. For the optimized design, the load curves were much smoother. Cracks were clearly visible on the surface of the conventional group only, and the directions of those cracks were perpendicular to those of the most tensile stresses. Results from the more sensitive AE measurement also showed that the optimized design had, on average, fewer cracking events: 38 versus 2969 in the conventional design. Significance: The much lower number of AE events and smoother load–displacement curves indicated that the optimized FRC bridge design had a higher fracture resistance. It is expected that the optimized design will significantly improve the clinical performance of FRC bridges. [Copyright &y& Elsevier]

Abstract: Congenital synechia of the gums is a rare malformation. The fusion may be partial or complete and may be associated with other facial dysmorphologic malformations. The synechia can be fibrous or bony and may develop between the upper and lower alveolar ridges. The authors report a newborn with partial, but broad and continuous, synechia of the gums and discuss its management during the first days of life. [Copyright &y& Elsevier]

Aim: To compare the fracture resistance of teeth restored with fiber-reinforced composite (FRC) posts and experimental dentin posts milled from human root dentin. Materials and Methods: Thirty maxillary central incisors were divided into three groups of ten each. Twenty teeth were restored with FRC posts and solid dentin posts and numbered as Groups 2 and 3 respectively while Group 1 acted as the control, without any post. The teeth were loaded at 135° angle to their long axes after core build-up and the failure loads were recorded. Results: One-way Analysis of Variance (ANOVA) and Bonferroni multiple comparisons revealed a significant difference among test groups with the control group showing the highest fracture resistance, followed by the dentin post group and lastly the FRC post group. Conclusions: Teeth restored with dentin posts exhibited better fracture resistance than those restored with FRC posts. [ABSTRACT FROM AUTHOR]

Background: The aim of this retrospective study was to assess the survival rate and causes of failure of quartz fiber posts used to restore endodontically treated teeth. Materials and Methods: Thirty-eight patients with endodontically treated premolar and anterior teeth that were then restored with a coronoradicular quartz fiber post and extensive composite resin restorations were selected for participation in the study. The age of the restorations ranged from 1 to 6 years. Survival probabilities of the restorations as well as causes of failures were analyzed using the Kaplan-Meier analysis and the Logistic regression (a = 0.05). Results: The overall cumulative survival rate (48.8%) was determined, while the survival probabilities after 1, 2, 4, 5, and 6 years of service were 88.37%, 60.95%, 45.71%, 32.65%, and 0%, respectively. Conclusions: The survival probability of endodontically treated teeth restored with a quartz fiber post and composite restorations is associated with the dental arch. [ABSTRACT FROM AUTHOR]

The aim of this study was to determine the retentive forces of fiber-reinforced composite (FRC) posts luted with different core build-up composite resins, and resin cements. Extracted single-rooted teeth were restored using FRC posts luted with the core build-up composites Build-It, Culmat, Flow White, Luxacore, Multi-Core Flow, Rebilda DC and luted with the resin cements Calibra, Cement-It, Multilink, and RelyX Unicem (control group, no separate etching, priming or bonding steps). The Rebilda DC was used with both the light-polymerizing Solobond and the dual-polymerizing AdheSE. Following water storage (37°C, 24 h) and thermal cycling (5000 cycles, 5-55°C, 30 s) tensile strength testing was performed and fracture modes were assessed. Statistical analysis of the data was done by one-way ANOVA, Bonferroni/Dunn correction, and unpaired t-test with α = 0.05. Except for Multilink (319 N, SD 50 N) and Cement-It (331 N, SD 85 N) significantly higher retentive forces were obtained for the core build-up composite Build-It (422 N, SD 43 N) and for the resin cements Calibra (408 N, SD 50 N) and RelyX Unicem (405 N, SD 64 N) compared to the other materials (p < 0.001). The lowest retentive forces were found for the core build-up composites Luxacore (145 N, SD 36 N) and Rebilda DC/Solobond (148 N, SD 39 N) (p < 0.001). Fracture modes were mainly interfacial. The use of core build-up composites did not improve the retentive forces of FRC posts compared to resin cements. Except for Culmat, core build-up composites as well as resin cements in combination with dual-polymerizing bonding materials were superior to composites with light-polymerizing bonding materials. [ABSTRACT FROM AUTHOR]