scispace - formally typeset
Search or ask a question

Showing papers on "Post and core published in 2008"


Journal ArticleDOI
TL;DR: Ex vivo the effects of different post systems and lengths on the strain and fracture resistance of root-filled teeth are investigated to find the fibreglass post was effective with the three post lengths, with higher fracture resistance than metal posts when the length was 5.0 mm.
Abstract: Aim To investigate ex vivo the effects of different post systems and lengths on the strain and fracture resistance of root-filled teeth. Methodology One hundred and thirty-five bovine incisors were sectioned 15 mm from their apices, root-filled and divided into three groups (n = 45): fibreglass post; prefabricated steel post; cast post and core. Each group was divided into three subgroups (n = 15) according to the post length: 5.0 mm; 7.5 mm; 10.0 mm. All teeth were restored with metal crowns. For strain-gauge measurement, two strain gauges per sample were used. The fracture resistance (N) was measured and the data were analysed with two-way analyses of variance, followed by the Tukey’s HSD test (α = 05). Results For all posts, decreased lengths resulted in increased microstrain values. However, the fibreglass posts were associated with lower increases when compared with cast post and cores and prefabricated steel posts, which showed microstrain values two times higher when the post length was 5.0 mm. The two-way analyses of fracture resistance values revealed that post length was statistically significant for the metal posts and not significant for the fibreglass post. The fracture mode analysis indicated that all groups tended to demonstrate root fractures in groups restored with metal posts and resin core fractures in groups restored with fibreglass posts. Conclusions The cast post and core when the length was 10.0 mm had the highest fracture resistance; however, the fibreglass post was effective with the three post lengths, with higher fracture resistance than metal posts when the length was 5.0 mm.

98 citations


Journal ArticleDOI
TL;DR: Marginal continuity of the crowns studied was better and more stress resistant when posts and cores were included in the restoration of endodontically treated teeth with complete ceramic crowns.
Abstract: STATEMENT OF PROBLEM: The influence of different crown foundations on marginal seal and fracture resistance of ceramic crowns placed on endodontically treated teeth has not been clearly established. PURPOSE: The purpose of this study was to evaluate the marginal continuity and fracture behavior of high-strength all-ceramic crowns with different substructures in endodontically treated premolars. MATERIAL AND METHODS: Forty-eight human mandibular premolars were assigned to 6 groups, including a no-treatment group (UNTREATED) and a group for which the access cavity was restored with composite resin (Tetric Ceram) (COMP). In the remaining 4 groups, teeth were prepared to receive all-ceramic crowns with 0.8-mm-wide shoulders and axial dentin heights of 2 mm. No posts were used in the ENDOCROWN group. Glass fiber posts (FRC Postec) were used in group FRC-POST. Group ZRO-POST received zirconia ceramic posts (CosmoPost), and group GOLD-POST received cast gold posts (CM). Experimental lithia disilicate ceramic crowns were made and adhesively cemented (Variolink). All teeth were subjected to thermal cycling and mechanical loading (TCML) in a masticatory simulator (1,200,000 loads, 49 N, 1.7 Hz, 3000 temperature cycles of 5 degrees C-50 degrees C-5 degrees C). Marginal continuity was evaluated with scanning electron microscopy at x200. All specimens were loaded to failure in a universal testing machine at 0.5 mm/min after TCML. Data were analyzed using 1-way ANOVA and post hoc t tests with Bonferroni correction (alpha=.05). RESULTS: Initially, mean values (SD) between 72.4 (15.8)% (ENDOCROWN) and 94.8 (3)% (FRC-POST) for continuous margins were found. With TCML, marginal continuity decreased significantly only in FRC-POST, to 75.5 (8.4)%, and in ENDOCROWN, to 44.7 (14.5)%. Mechanical load testing measured mean loads to failure between 1092.4 (307.8) N (FRC-POST) and 1253.7 (226.5) N (ZRO-POST) without significant differences between groups. Deep root fractures were observed in half of the specimens, irrespective of their groups. CONCLUSIONS: Marginal continuity of the crowns studied was better and more stress resistant when posts and cores were included in the restoration of endodontically treated teeth with complete ceramic crowns. The placement of a post-and-core foundation did not influence the pattern of failure.

70 citations


Journal ArticleDOI
TL;DR: It is suggested that to reduce stress in the remaining radicular tooth with a large coronal defect, it is recommended to accompany a composite resin core with a fiber post of a large diameter.
Abstract: Using three-dimensional finite element analysis (3D-FEA), stress distributions in the remaining radicular tooth structure were investigated under the condition of varying diameters of fiber post for fiber post-reinforced composite resin cores (fiber post and core) in maxillary central incisors. Four 3D-FEA models were constructed: (1) fiber post (φ1.2, φ1.4, and φ1.6 mm) and composite resin core; and (2) gold-cast post and core. Maximum stresses in the tooth structure for fiber post and core were higher than that for gold-cast post and core. In the former models, stresses in the tooth structure as well as in the composite resin were slightly reduced with increase in fiber post diameter. These results thus suggested that to reduce stress in the remaining radicular tooth with a large coronal defect, it is recommended to accompany a composite resin core with a fiber post of a large diameter.

67 citations


Journal ArticleDOI
TL;DR: The results were highly dependent on remaining dentine thickness, and Roots restored with custom cast cores had the highest fracture strength, followed by prefabricated metallic posts and carbon fibre posts, regardless of root conditions and thermomechanical aging.
Abstract: Aim To evaluate the influence of remaining dentine thickness around post and core systems and the thermo-mechanical stresses on fracture resistance of bovine roots. Methodology This study involved 288 bovine incisor roots with standardized dimensions. Roots were randomly distributed into 24 groups (n = 12) according to root conditions [intact, semi-weakened, or weakened] and post and core systems [custom cast core, composite resin core, prefabricated metallic post, or prefabricated carbon fibre post], submitted or not to thermomechanical aging [5000 thermal cycles and 100 000 mechanical cycles at a 135-degree angle to the long axis of the root]. Specimens were submitted to a tangential compressive load (135° angle) at a crosshead speed of 0.5 mm min−1 until failure. Fracture resistance data were analyzed using 3-way anova and Tukey test: α = 5%. Results Roots restored with composite resin cores demonstrated no resistance to mechanical aging. No statistically significant difference was observed between aged and nonaged specimens involving all post-systems. Roots restored with custom cast cores had the highest fracture strength, followed by prefabricated metallic posts and carbon fibre posts, regardless of root conditions and thermomechanical aging. The remaining dentine thickness affected significantly roots restored with custom cast cores; weakened roots had a lower fracture resistance. Conclusions Although custom cast cores had a higher fracture resistance when compared to the other techniques, the results were highly dependent on remaining dentine thickness. Prefabricated posts performed in a similar manner in intact, semi-weakened and weakened roots reinforced with composite resin.

66 citations


Journal ArticleDOI
TL;DR: The authors reviewed the current evidence for the ferrule effect and examined the influence various post and core materials have on it, and the importance of planning for failure was discussed and the means of achieving a ferrule are discussed.
Abstract: When the supra-marginal dentine of a root-filled tooth is engaged by a crown, it may create a stronger tooth/restoration complex. This has been termed the ferrule effect. This paper reviews the current evidence for this effect and examines the influence various post and core materials have on it. Means of achieving a ferrule are discussed and the importance of planning for failure is considered.

43 citations


Journal ArticleDOI
TL;DR: The use of an intraradicular post in premolars with class II cavities can significantly increase the resistance towards extra-axial forces.

42 citations


Journal ArticleDOI
TL;DR: It is concluded that glass fiber reinforced post with composite core when used in single rooted upper anterior teeth are associated with a higher success rate in restoration of endodontically treated teeth.
Abstract: Aim: Restoring endodontically treated teeth is one of the major treatments provided by the dental practitioner. Selection and proper use of restorative materials continues to be a source of frustration for many clinicians. There is controversy surrounding the most suitable choice of restorative material and the placement method that will result in the highest probability of successful treatment. This clinical study compares two different varieties of fiber posts and one cast post and core in terms of mobility of crown margin under finger pressure, recurrent caries detected at the crown margin, fracture of the restoration, fracture of the root and periapical and periodontal pathology requiring crown removal over the period of 12months as evaluated by clinical and radiographical examination. Materials and Methods: 30 root canal treated, single rooted maxillary anterior teeth of 25 patients in the age range of 18-60 years where a post retained crown was indicated were selected for the study between January 2007 and August 2007; and prepared in a standard clinical manner. It was divided into 3 groups of 10 teeth in each group. After post space preparation, the Carbon fiber and Glass fiber reinforced posts were cemented with Scotch bond multipurpose plus bonding agent and RelyX adhesive resin cement in the first and second groups respectively. The Cast post and cores were cemented with Zinc Phosphate cement in the third group. Following post- cementation, the preparation was further refined and a rubber base impression was taken for metal-ceramic crowns which was cemented with Zinc Phosphate cement. A baseline periapical radiograph was taken once each crown was cemented. All patients were evaluated after one week (baseline), 3 months, 6 months and one year for following characteristics mobility of crown margin under finger pressure, recurrent caries detected at the crown margin, fracture of the restoration, fracture of the root and periapical and periodontal pathology. Results: Results after 12 months showed that none of the restorations among groups of cast post and core, carbon fiber reinforced post and glass fiber reinforced post with composite core restorations failed in terms of recurrent caries detected at the crown margin, fracture of the restoration, fracture of the root and periapical and periodontal pathology. One case of cast post and core and one case of carbon fiber reinforced post with composite core restorations showed slight mobility of crown margin under finger pressure at 12 th month recall but all the cases of glass fiber post with composite core restorations did not show any signs of mobility of crown margin under finger pressure at all the recall periods on clinical and radiographical examination. Conclusion: From this 12 months clinical evaluation of all the cases in the 3 groups comprising of cast post and core; carbon fiber reinforced post with composite core and glass fiber reinforced post with composite core restored with porcelain fused to metal crowns, it is concluded that glass fiber reinforced post with composite core when used in single rooted upper anterior teeth are associated with a higher success rate in restoration of endodontically treated teeth.

33 citations


Journal ArticleDOI
TL;DR: Teeth restored with custom cast post core were better resistant to fracture than teeth restored with prefabricated titanium post and composite core.
Abstract: Aim: To evaluate the effect of post reinforcement, post type and ferrule on the fracture resistance of endodontically treated maxillary central incisors. Materials and Methods: Sixty central incisor teeth were selected and grouped into six groups, viz. A, B, C, D, E, and F, each consisting of 10 specimens. Group A specimens were not subjected to any restorative treatment. Group B specimens were endodontically treated and crowned. Specimens of groups C and D were restored with custom cast post and core. Specimens of groups E and F were treated with prefabricated titanium post and composite core. Specimens of groups C and E were restored with porcelain-fused metal (PFM) crown having 2 mm ferrule. Specimens of groups D and F were restored with PFM crown having no ferrule. All the specimens were subjected to load (newton, N) on the lingual surface at a 135° angle to the long axis with a universal testing machine until it fractured. The fracture load and mode of fracture of each specimen were noted. One-way analysis of variance with Tukey honestly significant difference procedure was employed to identify the significant difference among the groups at 5% level (P Results: There were significant differences among the six groups studied (P Conclusion: The results showed that endodontically treated teeth restored with custom cast post core were as strong as the untreated group. Teeth restored with custom cast post core were better resistant to fracture than teeth restored with prefabricated titanium post and composite core. Ferrule is more important in custom cast post core than in prefabricated post and composite core.

25 citations


Journal ArticleDOI
TL;DR: The fiber post and composite resin core was found to be most effective from the standpoints of failure load, failure mode, and durability.
Abstract: From a selection of four kinds of post and core systems, including a fiber post and composite resin core, the purpose of this study was to determine the most effective system for the restoration of endodontically treated teeth with 0 mm of coronal tooth structure. For experimental abutment teeth, typical human maxillary central incisor teeth were modeled using bovine mandibular incisor teeth. By means of a static loading test, the four restoration systems were evaluated and compared in terms of failure load and failure mode. Further, by means of a cyclic loading test, these systems were assessed in terms of durability. For fiber post and composite resin core, it excelled from the standpoints of failure load and failure mode, and fared favorably too in durability after cyclic loading test. For composite resin post-and-core, it also showed excellent results for both failure load and failure mode in static loading test, but durability significantly decreased with cyclic loading. Taken together, the fiber post and composite resin core was found to be most effective from the standpoints of failure load, failure mode, and durability.

22 citations


Journal ArticleDOI
TL;DR: With glass fiber posts and conventionally cemented zirconia posts, restored teeth failed mostly in an "unfavourable" mode, and there was no statistical difference between the restoration of non-vital premolars with class II cavities with crowns and posts or crowns alone.

15 citations


Journal ArticleDOI
TL;DR: The loading test showed that neither cementation mode nor fatigue testing had an influence on the load bearing capability of endodontically treated bovine incisors restored with zirconium dioxide posts and crowns.
Abstract: The aim of the study was to evaluate the influence of fatigue and cementation mode on the fracture behavior of endodontically treated bovine incisors restored with zirconium dioxide posts and crowns. Forty-eight endodontically treated bovine primary incisors were restored with zirconium dioxide posts (Cerapost, Brasseler), composite build-ups, and crowns cast from a chromium cobalt alloy. In 16 teeth, each of the posts was cemented conventionally with KetacCem (3M ESPE) or adhesively with Panavia F (Kuraray) or RelyX UniCem (3M ESPE). One-half of the specimens in each group were subjected to thermocycling with 10,000 cycles at 5-55 degrees C and mechanical aging, loading the specimens at an angle of 45 degrees in 1,200,000 cycles with 50 N. Fracture resistance was determined by loading the specimens until fracture at an angle of 45 degrees to the long axis of the teeth. The loading test showed that neither cementation mode nor fatigue testing had an influence on the load bearing capability. Most specimens fractured in a favorable way, independent from the type of cementation.

Journal ArticleDOI
TL;DR: The fracture strength and marginal adaptation of root filled maxillary central incisors restored with glass fibre-reinforced posts, various core materials and all-ceramic crowns were investigated ex vivo.
Abstract: Aim To investigate ex vivo the influence of direct placement core materials on the fracture strength and marginal adaptation of root filled maxillary central incisors restored with glass fibre-reinforced posts, various core materials and all-ceramic crowns. Methodology Forty-eight human maxillary incisors were root filled. Posts were placed and teeth restored with composite cores and crowns (n = 8). Six core materials were examined after thermal cyclic and mechanical loading (TCML). Fracture force was determined under static loading. The marginal adaptation at the interfaces between cement-tooth and cement-crown were categorized as ‘intact margin’ or ‘marginal gap’ using scanning electron microscopy. Statistical analysis was undertaken with the Mann–Whitney U-test (α = P ≤ 0.05). Results Median fracture strength varied between 204 N (low viscous experimental core) and 1094 N (Multicore). No difference in fracture resistance was found with varying viscosity of the core material. The layering technique improved the fracture performance (P = 0.059) to a minor degree. Crowns with dedicated core materials (Rebilda 1063 N; Multicore 1094 N) had a significantly higher fracture resistance than crowns with a conventional restorative material (Tetric Ceram 509 N). Significantly poorer marginal adaptation before TCML was found for the layering technique at the tooth–cement interface and for all experimental cores after TCML. At the crown–cement interface significant differences in marginal adaptation could be determined between Multicore-layered core (P = 0.002) and Multicore-Rebilda (P = 0.001) after TCML. Conclusions The fracture strength of post and core restorations was dependent on the core material and bonding system. Marginal adaptation was influenced by the method of application of the core material and by TCML.

Journal Article
TL;DR: This type of post and core construction allows the dentist to avoid the pitfalls of poor fitting prefabricated posts, separate core materials, and delays in making the final crown restoration by constructing them chairside and avoiding the laboratory time involved in casting a custom metal post.
Abstract: Endodontically treated teeth pose a unique restorative challenge. This challenge is magnified in the esthetic zone when an all-ceramic crown is the desired final restoration. When choosing a treatment modality, the dentist must consider the physical properties of post and core materials and couple those considerations with the patient's demand for life-like restorative results. As computer-aided design/computer-aided manufacturing (CAD/ CAM) technology enters the mainstream of dentistry, an ideal passive custom ceramic post and core may be constructed chairside or ordered from a dental laboratory. CAD/CAM offers unmatched precision and versatility for the construction of dental posts and cores. This type of post and core construction allows the dentist to avoid the pitfalls of poor fitting prefabricated posts, separate core materials, and delays in making the final crown restoration by constructing them chairside and avoiding the laboratory time involved in casting a custom metal post.

Journal ArticleDOI
TL;DR: It was shown that the resulting forces are strongly dependent on the precise design of the test set-up and results from different geometries cannot be compared directly.
Abstract: To assess the usefulness of different post and core materials and systems, in vitro testing of fracture strength and fatigue resistance is a useful tool. However, the literature does not present coherent results as to which system can withstand the highest loads. With a geometrical model, the effects of load angulation and contact point location on the generated forces were calculated. To validate the mathematical model, a set of measurements was performed with a set-up that made it possible to measure the critical forces on a post and core restoration. A high level of correlation between the predictions of the model and the measurements was found. It was shown that the resulting forces are strongly dependent on the precise design of the test set-up and results from different geometries cannot be compared directly. Very strong sensitivity to small misalignment was found, all of which serves to explain the large differences in the literature.

Journal ArticleDOI
TL;DR: A first in vitro test of the stability showed that the positive locking provides at least as good extraction resistance as conventional post without the critical reliance on the luting/bonding agent.
Abstract: The design of a post and core restoration is a trade-off between a series of requirements to achieve stability of the post itself, the surrounding root dentine and the joint between tooth and post, while maintaining a sufficient apical seal of the remaining root canal filling. Post and core restoration systems come in a variety of different designs and dimensions, where each has its specific strength and weakness. With the exception of threaded versions, posts normally rely on either chemical and/or frictional locking between the post and the remaining root. Failure due to fatigue of the joint or root fracture due to overloading of the dentine is a frequent failure mode, especially for posts anchoring removable prostheses. Perforation of the root in an attempt to maximize the post length is a main cause for failure, too. A new design is proposed which uses a short but large diameter post. The risk of decementation is reduced by positive locking. A cavity with an undercut is prepared into the root, into which the post is fitted. Once joined, the post cannot be separated from the tooth without destruction of either the root or the post. The principle of the new design uses preparation tools and a post which is spread at the bottom. A cylindrically prepared hole is re-shaped to a defined inverse taper with the wider diameter at the bottom of the hole. A cylindrical post is inserted and spread at the bottom to a matching shape after placement. A first in vitro test of the stability showed that the positive locking provides at least as good extraction resistance as conventional post without the critical reliance on the luting/bonding agent.

01 Jan 2008
TL;DR: The complex procedure was designed to manage this case including orthodontic extrusion to move the fracture line above the alveolar bone, surgical fibrotomy to prevent relapse (intrusion) and finally the tooth was restored prosthodontically.
Abstract: In this paper a case report of a patient with crown−root fractured premolar was presented. The fracture line was located subgingivally in the level of alveolar crest at the palatal and mesial aspect and extending 2 mm supra−gin− givally at the distal aspect. Only the buccal part of a crown was not damaged. The radiographic examination con− firmed the clinical findings and also revealed that the tooth had earlier been treated endodontically. To avoid sur− gical extraction and remain crown−root fractured tooth, the complex procedure was designed to manage this case including orthodontic extrusion to move the fracture line above the alveolar bone, surgical fibrotomy to prevent relapse (intrusion) and finally the tooth was restored prosthodontically. Prosthetic treatment was based on per− forming a post and core, and porcelain crown on the extruded tooth. The final effect was successful and resulted in good esthetics and secured periodontal health. Moreover at the 12−month follow−up, the periodontal tissues were normal and neither luxation nor relapse was noted (Dent. Med. Probl. 2008, 45, 2, 211–214).

Journal ArticleDOI
TL;DR: A new post-and-core design which makes use of positive locking (rather than relying on chemical bonding agents for retention in the residual root) was proposed, and the introduced new geometry has significant advantages over the classical restoration.
Abstract: Human teeth with substantial coronal defects are subject to reconstruction by means of post-and-core restorations. Typically, such a restoration comprises a slightly cylindrical post onto which an abutment of varying shape, depending on the designated restoration, is attached. As clinical results are not satisfactory to date, a new post-and-core design which makes use of positive locking (rather than relying on chemical bonding agents for retention in the residual root) was proposed. Using proprietary burs, an inversely conical hole is machined into the root, into which the prefabricated post-and-core restoration is inserted. This part can be spread at the bottom to match the cavity's undercut form, resulting in a positive lock which can only be separated by destruction of root, restoration or both. Another key feature of this system is a ring/groove geometry which is able to absorb the wedging forces created by said spreading and the stress of loading of the restoration which arises from mascatory forces. To assess the properties, especially in terms of the stress imposed on the remaining tooth at highest possible loading, both finite element simulations and in vitro failure tests were performed and the findings compared. The results suggest that the parameters of the finite element simulations are in good agreement with reality. As calculated and measured force levels immediately before failure of the restoration are high, the introduced new geometry has significant advantages over the classical restoration.

Journal ArticleDOI
TL;DR: Assessment of whether the root has to endure higher overall stress levels which ultimately may lead to failure of one of the components involved, and a new proprietary post and core design which makes use of positive locking.
Abstract: Human teeth with substantial coronal defects are subject to reconstruction by means of post and core restorations. Typically, such a restoration comprises a slightly cylindrical post onto which an abutment of varying shape, depending on the designated restoration, is attached. As clinical results are not satisfactory to date, we proposed a new proprietary post and core design which makes use of positive locking. As this prefabricated system is not customised to an individual root's cross-sectional geometry (usually oval), a varying amount of radicular dentin is left in periphery of the core's outer edge. The aim of this study was to assess the implications of this fact, i.e., whether the root has to endure higher overall stress levels which ultimately may lead to failure of one of the components involved. A series of finite element simulations were performed to evaluate stress and strain on the system, in which the proposed post and core was embedded into a virtual dentin cylinder of different diameters, ranging from flush mounting of the restoration to a dentin excess of 4 mm, and subsequently loaded with forces with two angles of attack (90 degrees and 130 degrees ). The results show that flush mounting yields an agreeable stress and strain distribution within the radicular dentin, but overall stress levels drop significantly with an excess of 0.5 mm of surrounding dentin. More than 1 mm excess was not found to have profound positive effects.

Journal Article
TL;DR: The Wuerzburg Post is a new post-and-core restoration system designed to eliminate the weak parts of post- and-core restorations and the associated problems, respectively, and achieves stress-free positive locking by means of a post which can be spread into a predefined and form-congruent undercut cavity.
Abstract: The Wuerzburg Post is a new post-and-core restoration system designed to eliminate the weak parts of post-and-core restorations and the associated problems, respectively. In contrast to conventional posts, the Wuerzburg Post is a short and thick post, which no longer relies on cementation or luting for retention in the root, but on stress-free positive locking, which it achieves by means of a post which can be spread into a predefined and form-congruent undercut cavity. The second key feature is an annular groove which runs in the dentin, girded by a corresponding structure, ensuring regular force transmission and stress dissipation, as opposed to the classic ferrule design. There are two versions: one with a machined core which can be prepared like a classic build-up to support crowns and bridges, and another one with a 2.25 mm ball end to connect to common dies which can be integrated into removable prostheses. As the system utilizes prefabricated parts made from Titanium, a precise fit is ensured, enabling the user to restore teeth quickly and easily. Over the course of the past three years, 129 posts were inserted, most commonly on upper and lower incisors and canines. The main application was restoration of fractured telescopes. During the observation period, five failures were observed. Two of the failiures did not cause significant damage to the tooth, and were subsequently immediately repairable. The survival rate amounts to over 95% after three years under risk.

Journal Article
Hou Lu1
TL;DR: When thePost-core-crown restoration and the post-and-core restoration are carried in clinical, the base tooth root has the different tooth essence stress change.
Abstract: Objective To compare and analyze the stress change of the post-core-crown and the post-and-core crown,under the different dentin ferrule,the different load condition.Methods To construct the post-core-crown and the post-and-core crown model of the second mandibular bicuspid.And the finite element analysis software ANSYS was used to solve the variation of the dentin Von Mises stress.Results To the Von Mises stress peak value's size of the dentin,there was no obvious change between post-core-crown and the post-and-core crown;But to the Von Mises stress peak value's distribution of the dentin,the post-core-crown tended to root direction of a tooth.Conclusion When the post-core-crown restoration and the post-and-core restoration are carried in clinical,the base tooth root has the different tooth essence stress change.



14 Oct 2008
TL;DR: It was concluded that conventional cast posts were more difficult to remove in comparison with posts with additional mechanical retention.
Abstract: Purpose: The objective of this study was to evaluate the use of ultrasound for removal of cast posts (CP) with different characteristics. Methods: Thirty uniradicular human teeth were endodontically treated and divided into three groups: G1 - conventional post (no additional mechanical retention); G2 - post with longitudinal groove; and G3 - post with transversal grooves. The posts were cemented inside the root canal using zinc phosphate cement, and the specimens were stored in room temperature for 24 h. The procedures for post removal included the use of ultrasonification (ultrasound equipment Multisonic S) and manual pushing with haemostatic tweezers. The period of time necessary for post removal was recorded, and data were analyzed by ANOVA and Tukey tests (5% level of significance). Results: Time for post removal was statistically different between groups G1 (3.7±1.5 min) and G2 (1.4±0.5 min) (P<0.001) and between G1 and G3 (2.3±1.2 min) (P=0.04). No difference was found between G2 and G3 (P=0.207). Conclusion: It was concluded that conventional cast posts were more difficult to remove in comparison with posts with additional mechanical retention. Key words: Post and core technique; Endodontics; ultrasound


Journal ArticleDOI
TL;DR: Evaluated the effect of a new abutment build-up method which combined an FRP post and metal core for a funnel-shaped root canal, which showed the highest value of about 240N, but there was no significant difference among those of MC, FM and ET.
Abstract: Recently, several fiber-reinforced plastic (FRP) posts have been applied for abutment build up; however, it is still unclear what type of build up is preferable for a funnel-shaped root canal. The purpose of this study was to evaluate the effect of a new abutment build-up method which combined an FRP post and metal core for a funnel-shaped root canal.As the tooth for abutment build up, an epoxy artificial maxillary lateral incisor was used. The artificial tooth was cut in the cervix part and a funnel-shaped root canal was formed in the root. As the materials for abutment build up, a glass fiber-reinforced plastic post, core resin and gold-silver-palladium alloy were used. Abutment build up was performed using the following three methods: 1. Combination of an FRP post and core resin by the direct method (FP); 2. Conventional metal core by casting (MC); 3. Combination of an FRP post, core resin and coronal metal core (FM). In addition, as a control, an artificial tooth prepared for abutment (ET) was used. A destruction test was carried out to measure the destruction strength and observe the destruction aspect.The destruction strength of FP was about 160N, significantly lower than that of MC, FM and ET. The destruction strength of FM showed the highest value of about 240N, but there was no significant difference among those of MC, FM and ET. When observing the specimen after the destruction test, FP, FM and ET were fractured or cracked near the cervix of the tooth, whereas MC was fractured near the center of the root.

01 Jan 2008
TL;DR: In this paper, a clinical sequence of fabrication of a post and core in a maxillary lateral incisor which had a large root canal was reported, and the use of a figlass post associated with accessory fi ber glass post was indicated.
Abstract: The use of figlass posts in the restoration of endodontically treated teeth has been extensively increased. However, due to different diameters and shapes (too elliptical or too large) of the root canals, the cement layer could be very thick, potentially increasing microleakage and decreasing the post and core fracture strength. This article reports a clinical sequence of fabrication of a post and core in a maxillary lateral incisor which had a large root canal. After clinical and radiographic analyses, the use of a figlass post associated with accessory fi ber glass post was indicated.