In vitro evaluation of the retention of composite fiber and stainless steel posts

PURPOSE: This study compared the tensile retentive strength of composite fiber-reinforced dowels luted with a resin cement to stainless steel dowels luted with zinc phosphate cement. MATERIALS AND METHODS: The crowns of 40 extracted human mandibular premolars were removed with a separating disc 1-mm coronal to the cementoenamel junction. The teeth were randomly divided into 4 groups (n = 10). A post space was prepared in each specimen to a depth of 9 mm, using the drill supplied by the respective manufacturer. For the stainless steel post group, 1.25-mm-diameter posts were cemented with zinc phosphate cement. For the composite fiber reinforced groups, posts with diameters of 1.00, 1.25, and 1.50 mm were luted with a Bisphenol A-Glycidyl Methacrylate (BIS-GMA) resin bonding system (Jeneric/Pentron, Wallingford, CT) according to manufacturer specifications. The specimens were stored in a sealed container with a moist environment for 24 hours, placed in a fixture in an 801 Materials Test Systems (MTS) machine (MTS Systems Corp, Minneapolis, MN), and loaded in tension at a rate of 5.0 mm/min until failure. Differences among the 4 groups were determined using a one-way analysis of variance and Tukey-B post-hoc tests (alpha = 0.05). RESULTS: The mean loads to failure ranged from 43.9 +/- 10.4 kg for the stainless steel dowel group to 19.9 +/- 5.7 kg for the composite fiber-reinforced 1.00-mm-diameter group. The stainless steel post luted with zinc phosphate cement provided significantly greater tensile resistance than all composite fiber dowel groups. The retention of the 1.00-mm composite fiber-reinforced post was significantly less than the remaining groups. CONCLUSIONS: Under the conditions of this study, the stainless steel dowel luted with zinc phosphate cement provided significantly greater retention.     

Retention of endodontic dowels: effects of cement, dowel length, diameter, and design.

The retentive capacity of three preformed endodontic dowel designs was compared at two lengths and two diameters, with three different cements. The greatest single factor influencing retention of these devices was the design used. Of the types tested in this study, the most retentive were threaded, parallel-sided dowels screwed into tapped channels. Serrated, parallel-sided dowels cemented in matched cylindrical channels provided intermediate retention, and smooth-sided tapered posts were the least retentive. Another major factor in retention was the length of imbedment into dentin. An increase in dowel imbedment depth usually corresponded to increased retention. The effect of cement type was significant only with tapered dowels. Zinc phosphate cement was most retentive, carboxylate cement exhibited intermediate retention, and the epoxy cement was least retentive. For the other post designs, cement type had no significant effect on retentive capacity. Finally, variations in dowel diameter had no significant effect on retentive ability.     

两种预成桩拉伸固位强度的体外研究

目的:比较用树脂粘接剂粘接的纤维增强复合树脂预成桩与用磷酸锌粘固的不锈钢预成桩的拉伸固位强度。方法:选择40颗因正畸拔除的下颌前磨牙,用金刚砂片在距釉牙骨质界冠方1 mm处去除牙冠,随机均分为4组,用预成桩配套用车针预备9 mm深的桩腔。对于不锈钢桩组,桩腔预备的直径为1.25 mm,用磷酸锌粘固粉粘固。对于纤维增强复合树脂桩组,桩腔预备的直径分别为1.00 mm、1.25 mm、1.50 mm,用树脂粘接剂粘接。储存24 h后,置于拉伸强度检测机上测量各组样本预成桩的拉伸固位强度,加载速度为5.0mm/m in,对各组的测量结果进行统计学分析。结果:各组预成桩的平均固位强度在(43.9±10.4)kg至(19.9±5.7)kg之间,磷酸锌粘固的不锈钢桩组的拉伸固位强度显著高于所有纤维桩组,1.00 mm纤维增强复合树脂桩组的固位强度明显低于其它组。结论:在本实验的研究条件下,磷酸锌粘固的不锈钢桩组固位强度最高。     

Effect of dowel length on the retention of 2 different prefabricated posts.

OBJECTIVE: To compare in vitro the retentive values of stainless steel, parallel-sided posts to quartz-fiber, tapered posts for 2 different dowel lengths (5 and 10 mm). METHOD AND MATERIALS: Both post systems were cemented with a dual-cure adhesive resin cement. Single-rooted extracted human teeth (n = 40) were decoronated and randomly divided into 4 groups of 10 samples each. Posts of 5 and 10 mm in length were luted with the resin cement. Each sample was placed on a universal testing machine, and using a push-out method, a vertical load was applied at a crosshead speed of 2 mm/min. The amount of force required to dislodge the post was recorded. The effect of post type and length was evaluated using a 2-way analysis of variance. RESULTS: A statistically significant main effect was found for post length (P <.001), with the 10-mm posts of both post systems requiring greater force to dislodge than the 5-mm posts. There was no interaction between post length and post type (P >.05). CONCLUSION: It is concluded from this study that there is no statistical difference in retention between quartz-fiber, tapered posts and stainless steel, parallel-sided posts when they are cemented with the same resin cement (P >.05). The study also concludes that adequate retentive values are achieved with both post systems at the shorter, 5-mm post length.     

A comparison of the retention of tooth-colored posts.

OBJECTIVE: The aim of this in vitro study was to compare the retention of five different esthetic post systems of similar dimensions in extracted teeth using titanium posts as controls. METHOD AND MATERIALS: Sixty recently extracted single-rooted, caries-free teeth were sectioned horizontally and mounted in acrylic resin. The samples were randomly allocated into six groups of 10 for post preparation. Post space preparation was carried out according to the individual manufacturer's instructions. All posts were bonded using Panavia F. A 4-mm hollow, metal sleeve was luted over the free end of each post prior to mounting in a universal testing machine, and the forces required to dislodge the posts using a cross-head speed of 5 mm/min were recorded. RESULTS: It was found that the parallel-sided Lightposts were significantly more retentive than all of the other posts. Parapost Fibrewhite posts were more retentive than tapered Lightposts and Snowposts. There was no significant difference between the retention of stainless steel Paraposts and any of the other groups. CONCLUSIONS: Serrated parallel-sided stainless steel posts were no more retentive than either parallel-sided or tapered tooth-colored posts in this study. When all groups were considered, post dimension appeared to influence retention, with parallel-sided posts being more retentive than tapered posts.     

Effect of surface treatment of titanium posts on the tensile bond strength.

OBJECTIVES: Retention of composite resins to metal can be improved when metal surfaces are conditioned. The purpose of this investigation was to investigate the effect of two conditioning treatments on the tensile bond strength of four resin-based luting cements and zinc phosphate cement to titanium posts. METHODS: The effect on tensile bond strength of (1) air-particle abrasion (50 microm Al2O3) and (2) silica coating (30 microm SiO(x)) and silanization of tapered titanium posts prior to luting with any of the four resin composite luting cements (Compolute) Aplicap, Flexi-Flow cemTM, Panavia 21 EX, Twinlook) were evaluated. The posts luted with zinc phosphate cement (Tenet) were considered as the control group. Following endodontic preparation of 100 intact anterior human teeth with hand instruments, the post spaces were prepared using the opening drills of the corresponding size of the posts. All posts were cemented into the roots according to the manufacturer's instructions of each cement. The specimens were first stored in water at 37 degrees C for 24 h and then subjected to thermocycling (5000 cycles, 5-55 degrees C, 30 s). The tensile strength values were measured on a universal testing machine at a cross-head speed of 0.5 mm/min. Data were analyzed statistically using ANOVA and corrected with Scheffé-test due to the significance levels (P<0.05). RESULTS AND SIGNIFICANCE: The composite resin luting cements did not show significant differences (P<0.05) showing values between (352+/-76N-475+/-104N) when the posts were air-abraded. After silica coating and silanization, significantly higher (P<0.05) tensile strengths were obtained for Compolute Aplicap (600+/-123N) than those of the other luting cements (Flexi-Flow cemTM: 191+/-62N; Panavia 21 EX: 375+/-77; Twinlook: 430+/-78N). No significant differences (P>0.05) were found between the tensile strength of the posts luted with zinc phosphate (414+/-102N) and the resin composite cements. Silica coating and silanization revealed the highest tensile bond strength in posts luted with Compolute Aplicap but it was not effective for the other experimental groups. Zinc phosphate cement exhibited tensile bond strength as good as resin composite cements.     

Effect of eugenol-containing endodontic sealer on retention of prefabricated posts luted with adhesive composite resin cement.

Reported studies have implicated eugenol in the reduction in retention of restorations luted with chemically cured composite resin cement. This study investigated the effect of residual eugenol in the root canal on the retention of ParaPost dowels cemented with Panavia EX composite resin. An attempt was also made to identify and to determine the most effective cleansing procedure. Findings of this study demonstrated a substantial decrease in retention of posts luted with Panavia composite resin cement in the presence of eugenol. Irrigation with ethyl alcohol (ethanol) or etching with 37% phosphoric acid gel was found to be effective in restoring the resistance to dislodgment of the posts, but alcohol produced the most consistent and reliable results.     

Effect of EDTA conditioning upon the retention of fibre posts luted with resin cements

Aim To determine if a final rinse with EDTA improves the short‐term in‐tooth retentive strength of adhesively luted fibre‐reinforced composite posts. Methodology Six different commercial fibre post systems were tested. Post spaces in extracted human anterior teeth were irrigated with either 6% NaOCl or 6% NaOCl followed by 17% EDTA. Posts were luted using the manufacturer’s recommended bonding agent and luting cement. Two different sizes of post were tested for each post system. After 24 h of storage, the retentive strength of the post to the tooth (14 per group, 336 total) was tested using a pull‐out technique. Three‐way anova and the Student–Newman–Kuels test were used to test the effects of irrigation regimen, post size and post brand on the retentive strength of the fibre post. Results Almost every sample failed at the interface between dentine and luting cement. Irrigation method did not have any significant effect (P > 0.14) for any group other than ParaPost Fibre White (P < 0.001). The overall retention of a post appeared to be correlated to the amount of surface texture on the post; the smooth ICEPost was the least retentive brand, the textured FibreKor and the ParaPost Fibre White posts were moderately retained, and the threaded Flexi‐Post Fibre and the Flexi‐Flange Fibre posts were the most retentive brands tested. For all brands, larger diameter posts were more retentive than smaller diameter posts (P < 0.008). Conclusions A final rinse of EDTA did not improve the short‐term retention of fibre posts except for ParaPost Fibre White.     

Effects of various cementation methods on the retention of prefabricated posts

Para-Post dowels were cemented by using combinations of cement, cleansing agents, and dentinal treatments. The comparative retentive strengths were as follows: 1. Para-Post posts cemented with composite into mechanically corrugated post spaces recorded the greatest retention. 2. The retention of the posts cemented with composite into post spaces rinsed with 1 ml of 17% EDTA with a pH of 7.5 and followed immediately by 1 ml of 5.25% NaOCl was lowest. 3. The retention of the posts secured with zinc phosphate into mechanically corrugated post spaces was significantly higher than with untapped post spaces. 4. The retentive strength of the posts placed with glass-ionomer cement into post spaces, irrigated with 1 ml of 40% polyacrylic acid solution, and rinsed with distilled water was comparable to that of posts secured with zinc phosphate cement without roughened post spaces.     

Factors influencing the removal of posts

AIM: To determine whether metal type, cement type and the use of ultrasonic vibration influence the amount of tensile force required to remove parallel-sided, prefabricated, metal posts from tooth roots. METHODOLOGY: Ninety extracted canine teeth were sectioned horizontally 1-mm coronal to the labial cemento-enamel junction and embedded in acrylic blocks. Standardized post spaces were prepared with a ParaPost no. 5 (1.25 mm) drill to 10 mm and ParaPost XP no. 5 stainless steel and titanium posts were cemented using zinc phosphate, glass ionomer or composite resin cement. Sixty posts were subjected to 16 min of ultrasonic vibration whilst 30 stainless steel posts received no vibration. The force required for post removal was determined using a universal testing machine. Results were analysed using univariate anova. RESULTS: The univariate anova revealed no statistically significant differences between the groups at the P = 0.05 level. CONCLUSIONS: In this in vitro experiment, metal type, cement type and ultrasonic vibration did not influence the force required to remove posts.     

Resistance to cyclic loading of teeth restored with posts

This in vitro study evaluated the effect of presence of post, presence of core, and of shape, type, and surface treatment of posts on resistance to cyclic loading of crowned human teeth. For all teeth, crowns designed without ferrule were cast in sterling silver and luted with resin cement (Panavia F). Each tooth underwent cyclic loading of 600 N at two loads per second until failure. Teeth that had only been crowned showed significantly higher resistance to cyclic loading than teeth with cores or with post and cores. No significant differences were found between teeth restored with cores only or with post and cores, irrespective of surface-treatment of the posts. Teeth restored with parallel-sided cast post (ParaPost XP) and cores showed significantly higher resistance to cyclic loading than teeth with either tapered cast posts or untreated prefabricated posts of titanium alloy (ParaPost XH) or glass fiber composite (ParaPost Fiber White). No significant difference was found between teeth restored with parallel-sided cast post and cores and teeth restored with untreated prefabricated posts of zirconia (Cerapost). Surface treatment of posts significantly increased the resistance to cyclic loading compared with untreated posts. When posts are used, surface treatment is recommended.     

Comparison of retentive properties of four post systems.

This study compared the retention of posts in the root for various diameters (1.3 mm and 1.6 mm) of three prefabricated post systems (Unity, Filpost, and Brasseler) with that of the previously reported No. 1 and No. 2 Flexi-Post systems. The experiment was divided into three groups comprising 10 samples for each post system studied. In group 2, the Filpost system was cemented both with a resin cement and zinc phosphate cement. Retention values were obtained with a modified universal testing machine. The retention of 1.3 mm posts from most to least retentive was Flexi-Post (zinc phosphate) greater than Filpost (zinc phosphate) greater than Filpost (resin) greater than Brasseler (zinc phosphate), greater than Unity (resin). The retention of 1.6 mm posts from most to least was Flexi-Post (zinc phosphate) greater than Filpost (zinc phosphate) greater than Brasseler (zinc phosphate), Unity (resin) greater than Filpost (resin). The Filpost system achieved higher retention with zinc phosphate cement than it did with resin cement.     

Comparison of Two Luting Agents Used for the Retention of Cast Dowel and Cores

PURPOSE: The first purpose of this study was to compare the retentive values of zinc phosphate and Panavia F resin cements when used for luting cast dowel and cores. The second purpose was to determine whether the use of a lubricant when making the resin pattern for a custom dowel and core would have an effect on the final retention of dowels cemented with either zinc phosphate or Panavia F cements. METHODS AND MATERIALS: Sixty-three caries-free extracted single-rooted human teeth were randomly divided into three groups of 21. Root canal preparations were standardized for all 63 teeth. Clinical protocols for fabricating and cementing dowel and core restorations were examined, comparing zinc phosphate and Panavia F resin cements. Direct dowel patterns were fabricated using the Para Post system and cast in a noble metal alloy. Group I dowel spaces were lubricated with GC lubricant prior to dowel pattern fabrication and cleaned with Cavidry solvent before cementing the cast dowel and core with zinc phosphate cement. Group II dowel spaces were rinsed with water only prior to dowel pattern fabrication. The dowels and cores in this group were cemented with Panavia F resin cement. Group III dowel spaces were lubricated with GC lubricant prior to dowel pattern fabrication; the dowel spaces were cleaned with Cavidry solvent before the cast dowel and cores were cemented with Panavia F cement. The tensile force necessary to remove the cast dowel and cores was determined using a universal testing machine. Results were statistically analyzed using one-way ANOVA and Tukey's HSD test. RESULTS: The dowels and cores in Group I had significantly higher retentive values than either of the two Panavia F groups (p< or = 0.001). No difference in retentive values (p > 0.05) was found between dowels luted with either of the lubricating agents in the Panavia F groups. CONCLUSIONS: Zinc phosphate cement had higher retentive values when cementing cast dowel and cores than Panavia F. The type of lubricant used for the resin dowel fabrication (water or GC lubricant that was removed with a solvent) had no effect on the retention of cast dowels cemented with Panavia F.     

Retention of prefabricated and individually cast root canal posts in vitro

OBJECTIVES: The aim of the study was to evaluate the retention of prefabricated root canal posts made of a variety of materials that have recently been introduced into dentistry. MATERIALS AND METHODS: The posts studied were CosmoPost, Composipost carbon fibres, Composipost Aestheti-Plus, Composipost Light-Post and Para Post Fiber White. The posts were luted in extracted human premolars and the cores were built up with the resin composites recommended by the manufacturers. The retention of individually cast gold alloy posts luted with zinc-phosphate cement were used as reference. A universal testing machine was used to determine the retention of each cemented post Data were compared using ANOVA supplemented with Fisher's PLSD at a significance level of p < 0.05. RESULTS: Only the CosmoPost system exhibited retention values that were significantly lower than for the conventionally cast gold alloy posts luted with zinc-phosphate cement The force necessary to loosen the CosmoPost specimens was significantly less than that needed to loosen the Composipost. Estheti-Plus (p < 0.05) and the Composipost Ught-Post systems (p < 0.001]. The force necessary to loosen the ParaPost Fiber White specimens was significantly less than for the Composipost Light-Post system (p < 0.01). Other combinations did not differ significantly (p > 0.05). CONCLUSIONS: When zirconium oxide ceramic posts are luted with resin composites the bonding between the ceramic and resin composite seems to be weak. Further studies are thus necessary to achieve improved retention of all-ceramic root canal posts.     

Effect of root canal sealers and irrigation agents on retention of preformed posts luted with a resin cement

This study examined the effect of three sealers and four irrigants on retention of Dentatus preformed posts luted with Panavia 21 resin cement. Gutta-percha with one of the following sealers--EWT, AH26, Nogenol, or no sealer (control)--was used to fill the root canals of 160 autoclaved incisor and premolar tooth roots. After 72 hr 8 mm post spaces were created with Dentatus Probos Pathfinders and Dentatus reamers. After irrigating the post spaces with saline, 5.25% NaOCl, 50% citric acid followed by NaOCl, or 40% H3PO4, followed by NaOCl, Panavia 21 TC cement was introduced into the canal on the Dentatus #4 stainless steel post's threads. An up-and-down and counterclockwise motion and then a forward twist seated the posts without engaging dentin. Mesiodistal and faciolingual radiographs visualized the chambers. After 72 hr posts were removed axially with an Instron at 5 mm/min. Surprisingly, using Nogenol sealer reduced post retention whereas EWT and AH26 increased retention compared with no sealer. Post retention improved after acid etchants, especially for AH26.     

The retentive effects of pre-fabricated posts by luting cements

The purpose of this study was to compare the retention of two different pre-fabricated posts cemented to the root canal with four different adhesive luting cements and a zinc phosphate cement. The crowns of 100 freshly extracted human mandibular central and lateral incisors were removed at the cementoenamel junction and divided into two main groups (A = ParaPost and B = Flexi-Post) and further divided into five subgroups to evaluate the effects of five different cements (Rely-X ARC, Panavia F, ParaPost Cement, Flexi-Flow Natural and Adhesor) each with 10 samples. Post-holes were prepared on all of the roots following the manufacturer's instructions. Each sample was placed into a specialized jig and tensile strength tests performed by using testing machine with a crosshead speed of 0.638 cm min(-1) and force applied until failure. The data were analysed with one-way anova (Post Hoc a Scheffe's S test) and two-way anova (P < 0.001). The Flexi-Post dowels had a mean of 54.21 kg (s.d. = 9.37) and demonstrated statistically higher retention than ParaPost dowels with a mean of 33.93 kg (s.d. = 10.69) for all of the cement groups (P < 0.001). In Flexi-Post and ParaPost dowel groups; Rely-X ARC was statistically higher than the Panavia F, ParaPost Cement, Flexi-Flow Natural and Adhesor (P < 0.05). Adhesor was significantly lower than the other subgroups (P < 0.05). Resin luting cements have demonstrated very high tensile strength potential for a strong bond to dentin.     

Retention and failure morphology of prefabricated posts

PURPOSE: This study evaluated the effect of cement, post material, surface treatment, and shape (1) on the retention of posts luted in the root canals of extracted human teeth and (2) on the failure morphology. MATERIALS AND METHODS: Posts of titanium alloy (ParaPost XH), glass fiber (ParaPost Fiber White), and zirconia (Cerapost) received one of several surface treatments-sandblasting, CoJet treatment, application of Metalprimer II, or sandblasting followed by silane application-and were then luted in the prepared root canal of human incisors and canines (n = 10). Following water storage at 37 degrees C for 7 days, retention was determined by extraction of the posts. Failure morphology of extracted posts was analyzed and quantified stereomicroscopically. RESULTS: Type of luting cement, post material, and shape of post influenced the retention and failure morphology of the posts. Because of limited adherence of the cement to the root canal, surface treatments did not always have a positive effect on retention. CONCLUSION: Choice of luting cement was critical for all three types of posts. Parallel posts showed superior retention to tapered posts.     

Various conditioning methods for root canals influencing the tensile strength of titanium posts

Conditioning the root canal is frequently advised to achieve high post-retention when resin composite luting cements are used. However, manufacturers' instructions for this purpose differ widely from one another. The aim of this study was to compare the tensile bond strengths of passive, tapered, titanium root posts that were luted with four different resin composite cements (Compolute Aplicap, Flexi-Flow cem, Panavia 21 EX, Twinlook) in the root canals at three conditions, namely (i) no conditioning, (ii) etching with 37% phosphoric acid, and (iii) etching + bonding agent application. Panavia 21 EX was further tested after using the primer for the post-surface according to the manufacturer's recommendations. The posts luted with zinc phosphate cement (Tenet) acted as the control group. Following endodontic preparation of 140 intact anterior teeth with hand instruments, the post-spaces were prepared using the opening drills of the corresponding size of the posts. The samples were first stored in water at 37 degrees C for 24 h and then thermocycled (5000 cycles, 5-55 degrees C, 30 s). The tensile strength values were measured with the universal testing machine at a crosshead speed of 0.5 mm min(-1). The data were analysed statistically using anova and corrected with Scheffé test due to the significance levels (P < 0.05). The tensile bond strengths of the titanium posts after luting with various cements and thermocycling were affected by the conditioning systems used for the root canals. Tensile bond strengths were the highest with Flexi-Flow (475 +/- 78 N) followed in descending order by Panavia 21 EX (442 +/- 97 N), Twinlook (430 +/- 78 N) and Compolute Aplicap (352 +/- 76 N) after conditioning the root canal. The use of primer on the post improved the tensile bond strength compared with the non-conditioned group for the Panavia 21 EX group (375 +/- 77 N) (P < 0.001). Tensile bond strengths obtained after luting the posts with zinc phosphate cement (414 +/- 102 N) were not significantly different (P < 0.05) than those of resin composite cements. Although the importance of conditioning the root canal was evident for Panavia 21 EX, it was not the case for the other luting cements tested.     

Effect of the dentin smeared layer on tensile strength of cemented posts

The tensile strengths for post lengths of 4 and 7 mm were compared in vitro with 3 different cementing media. In one group, the post preparation was rinsed with 5.25% NaOCl and in the other with 17% EDTA followed by 5.25% NaOCl. The EDTA-NaOCl flush had a profound effect when unfilled resin was used to cement the posts. A 4 mm post cemented with resin in the EDTA-NaOCl group was one and one-half times as retentive as a 7 mm post cemented with zinc phosphate and twice as strong as the 7 mm post with polycarboxylate cement. The 7 mm post cemented with the resin after the EDTA-NaOCl rinse was twice as resistant to displacement as the 7 mm post cemented with zinc phosphate and three times stronger than the polycarboxylate cement.     

Effect of surface treatment on retention of glass-fiber endodontic posts

STATEMENT OF PROBLEM: The effects of surface treatment on the retention of prefabricated fiber-reinforced epoxy resin posts are not well understood because most studies measure retention shortly after cementation, without artificial aging. PURPOSE: The purpose of this study was to evaluate the effect of surface treatment on the retention of glass-fiber endodontic posts luted with resin cement and subjected to artificial aging. MATERIAL AND METHODS: Thirty-two single-rooted teeth were selected, the coronal aspect of each tooth was removed, and the remaining root received endodontic therapy. Specimens were then divided into 4 groups (n = 8). Post spaces were prepared to a depth of 10 mm by using ISO 90 rotary instruments. The tapered posts received 1 of 4 surface treatments: cleaning with alcohol (Alc), cleaning with alcohol and conditioning with ED-Primer material (Alc-ED), airborne-particle abrasion (Air), or airborne-particle abrasion and conditioning with ED-Primer material (Air-ED). All posts were luted with a composite resin luting agent (Panavia F) after conditioning the canal dentin with autopolymerizing dentin primer (ED-Primer) and without acid etching of the canal dentin. After cementation, the specimens were stored in water at 37 degrees C for 30 days and subjected to simulated aging conditions consisting of 7500 thermal cycles (5 degrees C/55 degrees C) and 300,000 mechanical loading cycles with 30 N. Retention (N) of the posts was measured with a universal testing machine with a crosshead speed of 2 mm/min. The data were analyzed using 1-way ANOVA and the Tukey HSD test (alpha = .05). The dislodged posts were also examined microscopically at x8 and x20 magnification to evaluate the mode of failure. RESULTS: The mean retentive values (N) and SDs of the test groups were as follows: Alc, 375.9 +/- 85.0; Alc-ED, 421.2 +/- 46.8; Air, 534.8 +/- 65.8; and Air-ED, 555.8 +/- 86.9. Airborne-particle-abraded posts had significantly higher retention compared with nonabraded posts (P < .001). Treating the post's surface with ED-Primer material prior to cementation had no significant effect on retention. The failure mode was purely adhesive at the resin cement-post interface for all nonabraded posts. A mixed failure mode, adhesive at the resin cement-dentin interface, at the resin cement-post interface, and cohesive in the resin cement, was observed for airborne-particle-abraded posts. CONCLUSION: Treating the surface of the posts with ED-Primer material before cementation with Panavia F cement produced no significant improvement in the retention of the posts. Airborne-particle abrasion of the surface of the post significantly improved the retention.