title: The use of reinforced composite resin cement as compensation for reduced post length. Bonding effectiveness and sealing ability of fiber-post bonding. Post-surface conditioning improves interfacial adhesion in post/core restorations. Failure of fiber posts after cementation with different adhesives with or without silanization investigated by pullout tests and scanning electron microscopy. Influence of laser irradiation on fiber post retention Finite element analysis and bond strength of a glass post to intraradicular dentin: comparison between microtensile and push-out tests. Effects of silane application on luting fiber posts using self-adhesive resin cement. Evaluation of Various Pretreatments to Fiber Post on the Push‐out Bond Strength of Root Canal Dentin Randomized clinical trial comparing the effects of post placement on failure rate of postendodontic restorations: preliminary results of a mean period of 32 months.
abstract: STATEMENT OF PROBLEM Cements that yield high retentive values are believed to allow use of shorter posts . PURPOSE This study investigated the use of reinforced composite resin cement as compensation for reduced dowel length . MATERIAL AND METHODS The retention values of  stainless steel posts ( parallel-sided ParaPost and tapered Dentatus in 5- , 8- , and 10-mm lengths ) luted with Flexi-Flow titanium-reinforced composite resin and zinc phosphate cements were evaluated . Single-rooted extracted human teeth with crowns ( n = 120 ) , removed at the cementoenamel junction , were r and omly divided into 4 groups of 30 sample s each . Different post lengths were luted with either Flexi-Flow or zinc phosphate . Each sample was placed into a specialized jig and on a tensile testing machine with a crosshead speed of 2 mm/min , applied until failure . The effect of different posts and cements on the force required to dislodge the dowels was evaluated with multiple analyses of variance ( ANOVA ) . One-way ANOVA with Scheffé contrast was applied to determine the effect of different post lengths on the retentive failure of posts luted with the 2 agents . RESULTS Flexi-Flow reinforced composite resin cement significantly increased retention of ParaPost and Dentatus dowels ( P<.001 ) compared with zinc phosphate . One-way ANOVA revealed no statistically significant difference ( P>.05 ) between mean retention of both dowels luted with Flexi-Flow for all posts length used ( 5 mm = 8 mm = 10 mm ) . Mean retention values of the groups luted with zinc phosphate showed a statistically significant difference ( P<.001 ) for the different post lengths ( 10 > 8 > 5 mm ) . Parallel-sided ParaPost dowels demonstrated a higher mean retention than tapered Dentatus dowels ( P<.001 ) . CONCLUSION In this study , Flexi-Flow reinforced composite resin cement compensated for the reduced length of shorter parallel-sided ParaPost and tapered Dentatus dowels OBJECTIVES To evaluate the push-out bond strength and the sealing ability of five adhesive cements routinely used for fiber-post bonding . METHODS Fifty extracted single-rooted teeth were r and omly divided in five groups and restored using Parapost FiberLux and the following luting agents : Panavia 21 ( PAN ) , Clearfil Esthetic Cement ( CLF ) , Variolink II ( VAR ) , RelyX Unicem ( UNI ) and experimental GC self-adhesive cement ( EGC ) . After 1 week of water storage at 37 degrees C , three sections ( coronal , middle and apical ) of 2 mm thickness were prepared from each specimen . Sealing ability was quantified with a fluid-filtration system ( Flodec ) during 10 min , after which the push-out bond strength was immediately measured . Data were analyzed with ANOVA ( push-out ) and Kruskal-Wallis ( sealing ability ) . RESULTS The push-out bond strength and sealing ability were not significantly different among the coronal , middle and apical sections for each luting agent . The highest push-out bond strength was measured for CLF ( 14.60+/-3.63 MPa ) , which was not significantly different from PAN ( 12.57+/-2.45 MPa ) , but significantly higher than VAR ( 11.09+/-4.09 MPa ) , UNI ( 11.29+/-4.31 MPa ) and EGC ( 7.65+/-4.79 MPa ) . When evaluating the sealing ability , significant differences were not found among PAN , CLF and VAR , and between UNI and EGC . The latter luting agents scored significantly lower than the former ones . The push-out bond strength was correlated to the sealing ability ( p<0.001 ) . SIGNIFICANCE The self-etching MDP-based cements presented the highest push-out bond strength . Although the bonding effectiveness of self-adhesive cements appears promising , their interaction with root dentin might be too weak to minimize microleakage at the post-cement-dentin interface OBJECTIVES To verify the influence of different etching procedures of the post-surface on microtensile bond strength values between fiber posts and composite core material s. METHODS 60 DT Light Posts were divided into 10 subgroups using five different chemical surface treatments and two composite material s to build-up the abutment . Chemical surface treatments including etching with potassium permanganate ; treatment with 10 % hydrogen peroxide ; treatment with 21 % sodium ethoxide ; etching with potassium permanganate and 10 vol.% HCl ; silanization ( control group ) were performed on the post 's surface . The build-up was performed using ( A ) Core Paste XP ( Dent Mat ) and ( B ) Unifil Flow ( GC ) . Two sample s of each group were r and omly selected to investigate the morphologic aspect of the post/core interface with a scanning electron microscope ( SEM ) . The remaining specimens were cut so as to obtain microtensile sticks that were loaded in tension at a cross-head speed of 1mm/min until failure . The statistical analysis was performed using two-way ANOVA and the Tukey 's test for post-hoc comparisons ( alpha=0.05 ) . RESULTS SEM examination showed an interpenetrating adhesion network between the treated fiber post-surface and the composite material in all the groups tested . The results achieved with potassium permanganate had a significant influence on microtensile interfacial bond strength values with both the tested material s. Post-superficial treatments enhanced the bond strength particularly of Core Paste XP . SIGNIFICANCE Etching procedures showed a similar effect on the post-surface and enhanced the adhesion of composite core build-ups as a result of micromechanical and chemical retention INTRODUCTION The aim of the study was to test retentive forces of different adhesive systems after cementation of glass-fiber posts with or without prior silanization of the post by using a pullout test and scanning electron microscope ( SEM ) observation to detect the mode of failure . METHODS Fifty-six roots were r and omly divided into 6 experimental and 2 control groups : ParaCore ( PAR ) , Paracore + silane ( PAR-SIL ) , RelyX Unicem ( RXU ) , RelyX Unicem + silane ( RXU-SIL ) , RelyX ARC ( RXA ) , RelyX ARC + silane ( RXA-SIL ) , negative control ( NEG-CON ) , and positive control ( POS-CON ) . ParaCore posts were placed in the experimental groups ( each n = 8) by using an adhesive resin with or without prior silanization . NEG-CON received uncemented posts ( n = 4 ) ; POS-CON received an active screw post with an adhesive ( n = 4 ) . All sample s were subjected to a pullout test in a universal mechanical testing machine for pullout tests and SEM to assess the fiber posts and the roots after the tests . RESULTS Mean failure load values for each ground were PAR 247.4 ± 59.3 N , PAR-SIL 240.5 ± 68.8 N , RXU 102.3 ± 22.8 N , RXU-SIL 106.4 ± 19.8 N , RXA 119.8 ± 27.3 N , RXA-SIL 125.8 ± 28.3 N , NEG-CON 0 ± 0 N , and POS-CON 412.9 ± 27.4 N. There was a statistically significant difference between the 3 experimental adhesive systems ( P < .001 ) and between each experimental group and NEG-CON and POS-CON ( P < .05 ) . PAR was significantly different from RXU and RXA ( P < .05 ) . No statistically significant differences existed between RXU and RXA and between the use of silanization or not . Representative sample s for SEM showed cohesive failure as the principal fracture mode for PAR and mainly adhesive failure for RXU and RXA . CONCLUSIONS The results indicated that silanization of fiber posts does not make a difference to prevent dislocation of a post . Full-etching systems demonstrated significantly higher retentive forces than self-etching systems The purpose of this in vitro study was to compare the bond strength between fiber post and laser-treated root canals . Forty single-rooted bovine teeth were endodontically treated and r and omly divided into four groups of equal size according to the root canal treatment : group 1 conventional treatment ( without laser irradiation ) ; group 2 Nd : YAG laser ( 1.5 W , 10 Hz , 100 mJ ) ; group 3 Er , Cr : YSGG laser ( 0.75 W , 20 Hz ) ; and group 4 Nd : YAG + Er , Cr : YSGG lasers . The fiber posts were cemented with an adhesive system + resin cement , in accordance with the manufacturer ’s instructions . A mini acrylic pipe was fixed on the coronal section of the post using a light-polymerized resin . Specimens were mounted on an acrylic pipe with a self-polymerized resin . Retention forces were determined using a universal testing machine ( 0.5 mm/min ) . Data were analyzed using one-way ANOVA and Tukey tests ( p < 0.05 ) . The post retention force in group 2 was found to be lower than that in the other experimental groups . Fractures were observed at the interface between the dentin and the resin in all groups . High-intensity lasers can be used in conventional endodontic treatment ; however , root canal surface irradiation using the Nd : YAG laser was shown to negatively affect the post retention force OBJECTIVE This study tested the hypothesis that the stress distribution and bond strength of glass posts to intraradicular dentin is influenced by the mechanical testing methodology . METHODS Thirty single rooted endodontically treated teeth were prepared for luting of tapered fiber-glass posts ( Reforpost , Angelus , Londrina , PR , Brazil ) with a conventional adhesive system and resin luting cement ( Adper Scotchbond Multi- purpose , Rely X ARC , 3 M ESPE , St. Paul , MN , USA ) . The teeth were r and omly divided ( n=10 per group ) into micro-push-out ( Mpo ) , hourglass- ( Mh ) and rectangular stick-shaped ( Ms ) microtensile testing groups before sectioning each root into five 1-mm-thick specimens . During specimen preparation for microTBS testing 46/50 stick and 4/50 hourglass specimens prematurely failed ; therefore , the Ms group could not be included in the mechanical testing . The remaining specimens were tested at 0.5 mm/min until bond failure . Stress distribution within each specimen type for the three mechanical test methods was analyzed by finite element analysis ( FEA ) . Qualitative analyses were carried out through Von Mises , XY and Sy criterion . RESULTS Mpo and Mh had a mean microTBS of 11.89+/-6.55 and 14.98+/-12.72 MPa , respectively , which was not significantly different ( p=0.1311 ) . The push-out test demonstrated a more homogenous stress distribution by FEA and less variability in mechanical testing . SIGNIFICANCE Therefore , the recommended testing method for determining the bond strength of glass posts to intraradicular dentin is by Mpo PURPOSE To evaluate the effects of different glass-fiber post surface treatments on the bond strength to root dentin . MATERIAL S AND METHODS Fifty bovine incisors were used in this study . After removing the crowns , the teeth were endodontically treated . The roots were r and omly divided into five groups according to post surface treatment . The groups were as follows : CO ( Control ) - no treatment ; G1 - RelyX Ceramic Primer ( silane ) only ; G2 - silane and Solobond M ; G3 - silane and Scotchbond Adhesive ; G4 - silane and Excite . For post cementation , RelyX Unicem was used according to the manufacturer 's recommendation and the roots were stored in a light-proof container with 100 % relative humidity for 24 h. The specimens were transversally sectioned . Subsequently , the cervical , middle , and apical regions of the root were positioned in a push-out device and tested at 0.5 mm/min using a universal testing machine ( Instron ) . The data were statistically analyzed with two-way ANOVA and Tukey 's post-hoc test . The fractured specimens were then observed under a stereoscopic loupe at 60X magnification . RESULTS No significant difference in bond strength was found among the groups that received a silane or silane plus an adhesive system ( p > 0.05 ) . However , the CO ( no silane ) showed the lowest bond strength . Regarding G1 , G2 , G3 , and G4 , the cervical region of the root canal attained better bond strengths than did the middle or apical regions . The most frequent failure mode occurred at the cement/dentin interface . CONCLUSION Silane application may be necessary to improve the adhesion of fiber posts luted with the self-adhesive resin cement evaluated here . The application of an adhesive layer between the fiber post and resin cement did not have any influence on the bond strength when the silane coupling was previously used Introduction : The aim of this in vitro study was to compare the effect of different pretreatments ( fiber post ) with the laser‐activated irrigation ( LAI ) technique ( for removal of the smear layer ) on root canal dentin in terms of push‐out bond strength ( PBS ) in a fiber post . Methods : Fifty freshly extracted m and ibular single‐rooted premolars were prepared , and LAI was applied to all roots ( 17 % EDTA was 5 mL for 120 seconds with an erbium , chromium : yttrium‐sc and ium‐gallium‐garnet laser [ 0.50 W , 20 Hz , 25 mJ ] ) . In addition , 50 quartz fiber posts were r and omly assigned to 5 groups ( n = 10 ) according to the surface treatments as follows : group S ( s and blasting ) , group N1 and group N2 ( neodymium : yttrium‐aluminum‐garnet laser irradiation [ 2 W , 200 mJ , 10 Hz , with pulse duration s of 180 or 320 microseconds ) , group HF ( 9.7 % hydrofluoric acid etched ) , and group C ( control with no treatment ) . Dual‐cure resin cement was adhered onto the fiber posts after they were covered with a silane agent , and then the posts were placed into the canal space using a Lentulo spiral . The PBS test was performed after all specimens were transversally sectioned ( root slices of 1‐mm thickness ) . Data were analyzed with 1‐way analysis of variance/Tukey post hoc test ( & agr ; = 0.05 ) . Results : The highest PBS value was observed in group S ( middle part ) , and the lowest value was observed in group C ( apical part ) . There were no statistical differences among the groups regardless of the part . Furthermore , when the PBS values of the different parts of dentin were compared within treated groups , significant differences were observed in all groups except group N2 ( P < .05 ) . Conclusions : Within the limitations of this study , it can be concluded that the LAI technique when used with 17 % EDTA had a significant effect on the amount of smear layer removed from the root canal dentin , which was also detected in the fracture pattern ( adhesive failure [ resin‐post interface ] ) . However , the various treatments of the fiber post did not improve the PBS of the root dentin . HighlightsIt is crucial to maximize the bond strength between the root dentin and resin and between the resin and fiber post for the success of post‐core restorations . EDTA + laser‐activated irrigation significantly reduces debris or smear layers from the root dentin wall . The mechanical treatments on the fiber post surfaces can not affect the push‐out bond strength ( PBS ) ; however , other additional parameters must be evaluated . Studies on the effects of different surface treatments on the fiber post and root dentin walls together with PBS could enrich the literature INTRODUCTION The aim of this r and omized clinical trial was to assess whether the placement of a fiber post ( DT Light Post ) ( DT ) and the amount of residual coronal dentin affect the time to failure of single-unit postendodontic restorations . METHODS Ninety patients providing 120 teeth were selected . Three groups ( n = 40 ) were defined on the basis of the amount of residual coronal dentin : 2-walls group , 2 or more coronal walls ; 1-wall group , 1 coronal wall ; no-wall group , no wall exceeding 2 mm above the gingival level . Within each group teeth were r and omized and allocated to 2 intervention groups ( n = 20 ) , including subgroups no post ( no root canal retention ) and subgroups post ( placement of DT ) . RESULTS After a mean observation period of 32.4 ( 13.7 ) months in subgroups no post , the failure rates were 10 % , whereas in subgroups post , failure rates of 7 % were observed ( P = .318 ) . In no-wall group post placement significantly affected the time to failure of total restorations ( P = .029 , log-rank test ) . Teeth without post retention revealed a significantly higher failure rate ( 31 % ) compared with teeth restored with post retention ( 7 % ) . CONCLUSIONS Within the observation time of the present study , fiber post placement was efficacious to reduce failures of postendodontic restorations only with teeth that exhibited no coronal walls . Post insertion for teeth showing a minor substance loss should be critically reconsidered
target: The available evidence indicated that the coronal region of the root canal bonded better to the glass fiber post  than apical regions .
  Phosphoric acid , hydrogen peroxide , and silane application enhance post ’s retentiveness .
  In light of the current evidence , surface treatment strategies increase the bond strength of glass fiber post to dentine .
  However , recommendations for st and ardized testing methods and reporting of future clinical studies are required to maintain clinical ly relevant information and to underst and the effects of various surface treatment of glass fiber post  and their bond strength with dentine walls of the root canal
background: The objective of this systematic review was to determine the influence of surface treatment of glass fiber posts  on bond strength to dentine .