Showing papers on "Post and core published in 2007"

Clinical performance of fiber post restorations in endodontically treated teeth: 2-year results.

Abstract: Purpose: This study evaluated the 2-year outcome of post-and-core restorative procedures in endodontically treated teeth. The effect of baseline factors (tooth type, number of residual coronal walls, and type of definitive restoration) on restoration failure was assessed. Materials and Methods: The consecutive sample design included 150 patients. A total of 162 teeth (57 anterior and 105 posterior) were restored. Sixty-nine teeth had 3 or 4 residual coronal walls, while 93 teeth had 2 or fewer walls. Crowns and direct resin composite restorations were placed in 121 and 41 teeth, respectively. After 23 to 25 months, all patients were evaluated. Logistic regression was used to identify the joint effect of variables recorded at baseline (P < .05). Results: The only failure modes observed were post debonding (4.3%, 2 in anterior teeth and 5 in posterior teeth) and endodontic failure (3.0%, 2 in anterior teeth and 3 in posterior teeth). All post debondings occurred in teeth with 2 or fewer coronal walls that were crown covered. All endodontic failures occurred in crown-covered teeth (1 failure in a tooth with 3 walls and the remaining 4 failures in teeth with 2 or fewer walls). Logistic regression found no statistical significance for any of the variables recorded at baseline. Conclusion: Restorations placed with the use of a fiber post and core resulted in 4.3% post debondings and 3.0% endodontic failures after 2 years of clinical service. Int J Prosthodont 2007;20:293‐298.

In vitro evaluation of the fracture resistance of anterior endodontically treated teeth restored with glass fiber and zircon posts

Abstract: Statement of problem The published information is equivocal regarding the fracture resistance of endodontically treated teeth restored with fiber posts. Additionally, little is known about the biomechanical performance of glass fiber and zircon posts. Purpose This in vitro study investigated the fracture resistance of anterior endodontically treated teeth prepared with a 2-mm ferrule, restored with glass fiber and zircon posts and composite resin cores or cast posts and cores. Material and methods Twelve matched pairs of teeth were obtained from 4 cadavers, and all were endodontically treated and prepared with a standardized 2-mm ferrule. According to a random number table, the 2 teeth from each matched pair were randomly divided into 2 groups. The test group consisted of 12 specimens restored with a glass fiber and zircon post (Fibio) and composite resin (Durafil) core. Twelve matching specimens restored with a nickel-chromium (NiCr) cast post and core served as the control. Specimens in both groups were cemented with resin cement (Panavia F). After cementation of cast NiCr complete crowns with zinc polycarboxylate cement (ShangChi), the specimens were loaded with an incremental static force at an angle of 135 degrees to the long axis of the root until failure occurred. A paired sample t test was used to compare the fracture resistance (N) of teeth restored with the 2 post-and-core systems (α=.05). Results The mean failure load of paired differences between the 2 groups was −261.3 ± 237.3 N. The test group exhibited significantly lower failure loads than the control group ( P =.004). All specimens displayed root fractures, most of which were oblique, with cracks initiating from the palatal cervical margin and propagating in a labial-apical direction. Conclusion Within the limitations of this study, the teeth restored with glass fiber and zircon posts demonstrated significantly lower failure loads than those with cast NiCr post and cores. All specimens failed via root fractures.

Fracture Strength of Endodontically Treated Teeth with Flared Root Canals and Restored with Different Post Systems

Abstract: Background: Many post systems are available to clinicians, yet no consensus exists about which one is better in restoring endodontically treated teeth. Purpose: This study evaluated the fracture strength of teeth with flared canals and restored with two fiber-reinforced resin systems (glass fiber: FRC Postec [Ivoclar Vivadent, Schaan, Liechtenstein]; quartz fiber: D.T. Light-Post [Bisco Dental Products, Schaumburg, IL, USA]), and one custom cast base metal (Ni-Cr) post and core system. Methods: Thirty anterior teeth had their crowns removed below the cemento-enamel junction and were endodontically treated. The canals were prepared for post fixation, and the canal walls were flared using a taper diamond bur. The prepared roots were randomly divided into three groups according to the post system. All posts were cemented with an adhesive resin cement. For the fiber-reinforced resin posts, cores were built up using microhybrid composite. Metallic crowns were luted using zinc phosphate cement. Specimens were loaded at 45 degrees in a universal testing machine at a crosshead speed of 0.5 mm/min until failure. The mode of failure was classified as repairable or nonrepairable. Results: Teeth restored with cast posts had fracture strength twice that of teeth restored with resin posts. Fiber-reinforced resin posts failed at a compressive force comparable to clinical conditions, but all failures were repairable. Conclusion: Fracture strength and mode of failure in anterior teeth with flared canals varied according to the type of post used to support a crown. CLINICAL SIGNIFICANCE Under the conditions of this study, cast posts are preferable to restore endodontically treated teeth with flared canals and no ferrule.

Clinical evaluation of root filled teeth restored with or without post-and-core systems in a specialist practice setting.

Abstract: Salvi GE, Siegrist Guldener BE, Amstad T, Joss A, Lang NP. Clinical evaluation of root filled teeth restored with or without post-and-core systems in a specialist practice setting. International Endodontic Journal, 40, 209‐215, 2007. Aim To assess survival rates and complications of root-filled teeth restored with or without post-and-core systems over a mean observation period of ‡4 years. Methodology A total of 325 single- and multirooted teeth in 183 subjects treated in a private practice were rootfilledandrestoredwitheitheracastpost-and-coreor with a prefabricated titanium post and composite core. Root-filled teeth without post-retained restorations served as controls. The restored teeth served as abutmentsforsingleunitmetal-ceramicorcompositecrowns or fixed bridges. Teeth supporting cantilever bridges, overdentures or telescopic crowns were excluded. Results Seventeen teeth in 17 subjects were lost to follow-up (17/325: 5.2%). The mean observation period was 5.2 ± 1.8 (SD) years for restorations with titanium posts, 6.2 ± 2.0 (SD) years for cast post-andcores and 4.4 ± 1.7 (SD) years for teeth without posts. Overall, 54% of build-ups included the incorporation of a titanium post and 26.5% the cementation of a cast post-and-core. The remaining 19.5% of the teeth were restored without intraradicular retention. The adjusted 5-year tooth survival rate amounted to 92.5% for teeth restored with titanium posts, to 97.1% for teeth restored with cast post-and-cores and to 94.3% for teeth without post restorations, respectively. The most frequent complications included root fracture (6.2%), recurrent caries (1.9%), post-treatment periradicular disease (1.6%) and loss of retention (1.3%). Conclusion Provided that high-quality root canal treatment and restorative protocols are implemented, high survival and low complication rates of single- and multirooted root-filled teeth used as abutments for fixed restorations can be expected after a mean observation period of ‡4 years.

Microleakage and fracture patterns of teeth restored with different posts under dynamic loading.

Abstract: Statement of problem Many studies concerned with the microleakage of endodontically treated teeth restored with posts and cores and subjected to loading can be found in the literature. However, no studies have investigated microleakage under dynamic loading with simultaneous dye penetration, which is more relevant to clinical situations. Purpose The purpose of this study was to compare microleakage and to classify fracture patterns of endodontically treated teeth restored with various post systems under dynamic loading. Material and methods The crown portions of 40 human mandibular incisors were sectioned at the cementoenamel junction, and the teeth were endodontically treated. Teeth were divided into 4 groups (n=10): teeth restored with a cast post and core, prefabricated metal post (ParaPost), fiber-reinforced composite resin post (FRC Postec), and ceramic post (Cosmopost). After preparing the post space, each post was cemented with dual-polymerized resin cement (DuoLink). With the exception of the cast post-and-core group, the cores were formed directly using a light-polymerized composite resin (Light-Core). An intermittent load of 98 N at 1 Hz was applied for 50,000 cycles at an angle of 135 degrees to the long axis of the restored teeth, which were immersed in a 0.5% basic fuchsin solution. The ratio of the dyed surface area to the total area of the sectioned root surface was determined using an image analysis program. The data were analyzed by a 1-way ANOVA and Duncan's multiple range test (α =.05). The fracture patterns of the teeth were classified according to their fracture propagation lines. Results The cast post group showed a significantly higher level of microleakage compared to the other groups (P=.001). Regarding the failure mode, the FRC Postec and Cosmopost groups showed fracture patterns that would favor retreatment. The number of cycles of repeated loading was not significantly different among the groups (P=.161). Conclusions Both FRC Postec and Cosmopost groups showed less microleakage under dynamic loading and fracture patterns favoring a retreatment of fractured specimens.

In vitro evaluation of fracture resistance and failure mode of internally restored endodontically treated maxillary incisors with differing heights of residual dentin.

Abstract: Statement of problem Some of the associated effects of different restorative systems placed in endodontically treated teeth with varying heights of residual dentin have yet to be examined in a comprehensive manner. There is a need for additional information regarding fracture resistance and mode of failure. Purpose The purpose of this in vitro study was to evaluate the effect of 3 different restorative techniques with varying amounts of remaining dentin heights on the fracture resistance and failure mode of endodontically treated teeth. Material and methods Three groups of 40 human maxillary incisors were subdivided into 4 subgroups (n=10) with respect to the uniform height of the residual coronal dentin, defined as 0-, 2-, 4-, or 5-mm from the cemento-enamel junction, and then restored internally using a composite resin (Z100 MP) (control group), a cobalt-chromium ceramic alloy custom-made cast post and core (IPS d.SIGN 30; CCPC group), or a carbon fiber post system (Tech Xop 2000; CFP group). All specimens were then restored with nonprecious cast crowns. Static loading tests were performed on each specimen until failure (crack without a complete fracture). The data were analyzed with 2-way ANOVA and Bonferroni-corrected t test for independent samples (α=.05). Failure was classified as either favorable (allowing repair) or catastrophic (not allowing repair). Results The fracture resistance values (N) for the 0-, 2-, 4-, and 5-mm residual dentin heights were: 88, 143, 154, and 202 for the control group, 230, 264, 364, and 383 for the CCPC group, and 153, 235, 346, and 357 for the CFP group, respectively. Generally, all the differences tested were statistically significant. The failure mode was catastrophic for no control specimens, for 36 CCPC specimens, and for 4 CFP specimens. Conclusions The highest and lowest fracture resistances were recorded for the CCPC and control groups, respectively, at each residual dentin height. An increased height of residual dentin generally provided greater fracture resistance. The fracture resistance of the CCPC group was, however, similar or only slightly higher than that of the CFP group when 2, 4, or 5 mm of residual dentin height was present. In contrast, the failure mode was favorable for almost all of the CFP and control groups, while it was catastrophic in most of the CCPC group. (J Prosthet Dent 2007;98:365-372)

Stress analysis of a maxillary central incisor restored with different posts.

Abstract: Objectives: To evaluate the effects of different post materials on the stress distribution in an endodontically treated maxillary incisor. Materials and Methods: A pseudo 3-dimensional finite element model was created in a labiolingual cross-sectional view of a maxillary central incisor and modified according to five posts with different physical properties consisting stainless steel, titanium, gold alloy, glass fiber (Snowpost), and carbon fiber (Composipost). A 200 N force was then applied from two different directions; a) vertical load on the incisal edge, b) 45 degree diagonal load above the cingulum location. Stress distribution and values were then calculated by considering the pseudo three dimensional von Mises stress criteria. Results: Under two loading conditions, post made of steel showed greatest stress concentration at the post/dentin interface followed by titanium, gold alloy, Snowpost and Composipost. However, Composipost, which elastic modulus was closer to the dentin, produced highest stress values at 1/3 cervical area. Conclusions: Within the limitation of this simulated mechanical analysis, we can conclude that the physical characteristics of posts were important on stress distributions in post and core applications. Glass fiber post revealed more balanced stress distribution under functional forces. (Eur J Dent 2007;2:67-71)

The management of an endodontically abscessed tooth: patient health state utility, decision-tree and economic analysis

Abstract: A frequent encounter in clinical practice is the middle-aged adult patient complaining of a toothache caused by the spread of a carious infection into the tooth's endodontic complex. Decisions about the range of treatment options (conventional crown with a post and core technique (CC), a single tooth implant (STI), a conventional dental bridge (CDB), and a partial removable denture (RPD)) have to balance the prognosis, utility and cost. Little is know about the utility patients attach to the different treatment options for an endontically abscessed mandibular molar and maxillary incisor. We measured patients' dental-health-state utilities and ranking preferences of the treatment options for these dental problems. Forty school teachers ranked their preferences for conventional crown with a post and core technique, a single tooth implant, a conventional dental bridge, and a partial removable denture using a standard gamble and willingness to pay. Data previously reported on treatment prognosis and direct "out-of-pocket" costs were used in a decision-tree and economic analysis The Standard Gamble utilities for the restoration of a mandibular 1st molar with either the conventional crown (CC), single-tooth-implant (STI), conventional dental bridge (CDB) or removable-partial-denture (RPD) were 74.47 [± 6.91], 78.60 [± 5.19], 76.22 [± 5.78], 64.80 [± 8.1] respectively (p 0.05). Their respective willingness-to-pay ($CDN) were: 1,782.05 [± 361.42], 1,871.79 [± 349.44], 1,605.13 [± 348.10] and 1,351.28 [± 368.62]. A statistical difference was found between the utility of treating a maxillary central incisor and mandibular 1st-molar (p < 0.05). The expected-utility-value for a 5-year prosthetic survival was highest for the CDB and the STI treatment of an abscessed mandibular molar (74.75 and 71.47 respectively) and maxillary incisor (86.24 and 84.91 respectively). This held up to a sensitivity analysis when the success of root canal therapy and the risk of damage to the adjacent tooth were varied. The RPD for both the molar and incisor was the favored treatment based on a cost-utility (3.85 and 2.74 CND$ per year of tooth saved respectively) and cost-benefit analysis (0.92 to 0.60 CND$ of cost per $ of benefit, respectively) for a prosthetic clinical survival of 5-years. The position of the abscessed tooth and the amount of insurance coverage influences the utility and rank assigned by patients to the different treatment options. STI and CDB have optimal EUVs for a 5-year survival outcome, and RPD has significantly lower cost providing the better cost:benefit ratio.

Three-dimensional finite element analysis of stress and strain distributions in post-and-core treated maxillary central incisors.

Abstract: Purpose: To estimate which combination of restorative materials resulted in the most homogeneous stress and straindistributions in post-and-core treated teeth.Materials and Methods:Eight experimental finite element models with different material configurations were simu-lated; both indirect and direct restorations were considered. An arbitrary load of 50 N was applied on the palatal sur-face of the crown at a 60-degree angle to the tooth’s longitudinal axis to simulate tearing function.Results: In all the models, the values of both strain and stress recorded in the middle third of the buccal aspect ofthe root surface were off the scale. In contrast, the minimum values were noticed at the level of both the apical por-tion of the post and the root apex.Conclusion: The mechanical properties of the crown and core materials influenced both the position of concentrationareas and the level of stress and strain along the dentin/cement/post interfaces.Keywords: post, composite, adhesive, endodontically treated teeth, finite element analysis.

Evaluation of the apical seal after intraradicular retainer removal with ultrasound or carbide bur.

Abstract: There are situations in which intraradicular retainers have to be removed and replaced. The objective of this research was to evaluate the apical seal after the removal of a custom cast post and core with a carbide bur or with an ultrasound apparatus. Twenty five roots of extracted human incisors were used. They were endodontically treated and prepared to receive the posts. The posts and cores were cast with 2 types of dental alloys, CuAlZn and PdAg, and were cemented with zinc phosphate cement. After 24 hours, they were removed using the two above mentioned techniques. Then, the roots had their external surface made impermeable by two layers of cyanoacrylate adhesive, leaving only the cervical area for dye penetration. The teeth were immersed in rhodamine for 24 hours. They were then cut and observed under an optical microscope and analyzed with appropriate software (Imagelab). The results were submitted to ANOVA, and they evidenced that, regarding the alloy factor, PdAg posts presented a larger mean infiltration value (2.23 ± 0.48 mm) as compared to the posts made of CuAlZn (1.39 ± 0.48 mm) (p = 0.025). Regarding the technique factor, there was no significant difference (p = 0.9) between the removal of the intraradicular retainer using ultrasound (1.99 ± 0.62 mm) or using a rotating cutting instrument (1.62 ± 0.62 mm). Under these experimental conditions, it was possible to conclude that the degree of apical leakage was directly related to the alloy type, and it was present in both techniques used.

Resistance to fracture of crowned endodontically treated premolars restored with ceramic and metal post systems.

Abstract: OBJECTIVES: The objective of this study was to assess the resistance to fracture of crowned endodontically treated premolars with varying ceramic and metal post systems under simulated occlusal load. METHOD AND MATERIALS: The study consisted of 60 extracted intact premolars with similar root diameter and length. Teeth were divided equally into 4 groups (n = 15) and prepared for posts and cast crowns as follows: group 1 = preformed metal post, composite core, and cast crown; group 2 = cast post and core and cast crown; group 3 = zirconia post, composite core, and cast crown; and group 4 = zirconia post and heat-pressed ceramic core and cast crown. All prepared teeth had 2 mm of sound dentin on which the cast crowns were cemented. A continuous load (kg) was applied by an Instron testing machine to the buccal cusp at a 30-degree angle to the long axis of each tooth at a crosshead speed of 2 mm/min until failure. One-way analysis of variance with Scheffe test was used to statistically compare the differences between groups. RESULTS: Mean failure loads (in newtons) for the 4 test groups were as follows: 1,103.3 (group 1), 1,234.5 (group 2), 826.6 (group 3), and 870.6 (group 4). No significant difference in failure load values was found among all tested groups (F[3,59] = 2.05; P >.05). The primary mode of failure (85%) in all groups was an oblique radicular fracture, either apical to the post or at the post level. Horizontal fracture (15% to 20%) of the root and post was found in groups 3 and 4. CONCLUSION: Within the limitations of this study, varying ceramic and metal post systems did not affect the failure resistance of teeth restored with full-coverage cast metal crowns, under simulated occlusal load.

Fracture resistance of endodontically treated teeth restored with fibre or cast posts

Abstract: The purpose of this study was to determine the fracture resistance of 4 post and core systems. 40 extracted maxillary canines (for orthodontic reason) were used for this study. The samples were divided into 4 groups, which were: Group (1) Cast post luted with Rely X ARC; Group (2) Cast post cemented with zinc phosphate; Group (3) Fibre post luted with Rely X + Filtek Z-250 as core material; Group (4) Fibre post luted with Rely X + Vitremer Core Build Up as core material. The post cores were loaded (N) to fracture by a universal testing machine and data were analyzed (Oneway ANOVA). The obtained fracture resistance results were as follows: Gr 1 (2103.50 N ± 185.75) > Gr 2 (1494.80N ± 164.04) > Gr 3 (1004.90 N± 108.72) > Gr4 (739.40 N ± 96.93). Vertical root fractures were observed in the cast post-core groups. Hybrid composite cores in group 3 showed cohesive failures, whereas resin modified glass ionomer cores in group 4 showed a failure of adhesive nature from dentin.

Zirconia post-pressed ceramic core-supported all-ceramic crown: Case reports and 4-year follow-up

Abstract: Esthetic restorations involving anterior teeth pose a challenge to any clinician. Increasing patient expectations and the search for metal-free restorations have led to the birth of all-ceramic restorations. All-ceramic restorations must combine the mechanical properties of metal and optical properties of ceramics to be accepted as an alternative to porcelain-fused to metal restorations. At present, zirconia-based materials stand out as the strongest, most esthetic and biocompatible material available as posts for all-ceramic restorations. All-ceramic crowns require all-ceramic post and core as foundation restoration, as they help to bring about the best possible esthetic outcome. Here, a zirconia prefabricated post was heat pressed with the core material to obtain a monobloc. This provided the foundation for the restoration of the tooth with all-ceramic crown. The article presents clinical cases and a 4-year follow-up of three cases treated using all-ceramic post/core/crown. The procedure is presented in detail.

An alternative post-and-core method for patients with limited interarch space

Abstract: Background The authors describe a technique for placement of a three-unit posterior fixed partial denture where one abutment lacked sufficient interarch space. Case Description This method involves the use of a cast post and core with a precision attachment soldered into the core to provide the necessary retention and resistance. The prosthesis is retained by a combination of cement and screw retention. Clinical Implications This method is desirable when there is insufficient interarch space for a conventional post-and-core restoration. Achieving internal reinforcement by connecting the precision attachment to the residual root should provide the prosthesis with retention and added stability.

Design and Finite Element Analysis of a New Custom Made Orthotropic Post Material for Dental Applications

Abstract: The aim of this work was to conduct a parametric study of the stress distribution of endodontically treated dental post and core of a central maxillary incisor, and to suggest a new post material which minimizes the chances of post debonding from the dentin. Three different post materials (two references and one made in our laboratory) have been analysed with finite element simulations, and compared stress distributions under loading conditions. The dentin-cement-post interfacial stresses have been evaluated to study the debonding phenomena of the dental post. From the study of 3 different posts, it was found that our new orthotropic glass post generates lower stresses than the titanium post for endodontically treated tooth. From the analysis of three different horizontal loading planes, it was found that the stress distribution is most sensitive to the applied load when the load is applied at the mid section of the crown. It has been found that post cement interfacial stress increases with increase in modulus of the post. For the integrated post and core made from the same material, our results suggest that the modulus of the post material should be as close as the modulus of the dentin at the apical part and as close as crown at the coronal part of the post to minimize the chance of interfacial debonding and enhance the reliability of dental post. It has been observed, from our simulations, that the modulus of the post is most important than either the post is isotropic or orthotropic.

Fracture resistance of residual teeth restored with two different post and core systems

Abstract: Objective: To compare the fracture resistance of endodontically treated teeth restored with two post and core systems with different elastic modulus. Methods: Twenty recently extracted human mandibular premolars were cut off from CEJ(enamelo-cemental junction) and randomly divided into two groups of ten each. Teeth in group-1 received fiber glass posts and composite resin cores and were restored with full crowns (FPC). Teeth in group-2 received cast Ni-Cr posts and cores and full crowns(CPC). Each specimen was embedded in acrylic resin and secured in a universal material testing machine. Force was loaded to them with the speed of 1mm/min until fracture occurred. Results: The breaking loads for group-1 and group-2 were 2.39±0.55KN and 3.06±0.27KN respectively and showed significant difference(P 0.05). Repairable fractures often happened to group-1 whereas un-repairable fractures often happened to group-2 (P 0.05). Conclusion: Traditional cast post and core system is more suitable for the teeth with adequate fracture resistance to endure bigger chewing pressure,while the fiber glass post and core system is propitious to conserve weak root.

[Retention of selected cores to all-ceramic posts in post-and-core system].

Abstract: Objective To compare the retention of selected cores to all-ceramic posts in post-and-core system,in which the ceramic core was combined with the post by direct sintering,adhering,and the composite resin core was formed onto the post.Methods A total of 15 all-ceramic post fabricated by alumina-zirconia nano-composite infil-trated ceramics were divided into three groups.In group A,forming and combining the ceramic core with the post by direct sintering.In group B,combining the ceramic core with the post by adhering.In group C,forming composite resin core onto the post.Each specimen was placed into a special jig along the post axis and subjected to a load on INSTRON 4302 universal testing instrument until failure.Results There was a statistically significant difference between the groups(P0.01).Group A showed a significantly higher retention which was 3.04 and 2.88 times as high as group B and C respectively(P0.01).There was no significant difference between adhering and composite resin core(P0.05).Conclusion A reliable retention of the core to the post can be achieved when the alumina-zirconia nano-composite infiltrated ceramic core is formed and combined with the post by direct sintering,which offers significantly higher retention than adhering and forming composite resin core onto the post.

Do All Endodontically Treated Teeth Require a Post

Abstract: Treatment modalities in restorative dentistry should be implemented with a solid rationale behind them and support from scientific studies. These principles, in conjunction with clinical experience, can dictate when and if a post is required when a tooth has undergone root canal treatment. Dentists know each tooth is anatomically different and should be diagnosed and treated with an individual approach when it comes to its restoration. It is tempting to follow a path that leads into a routine in which every tooth receives the same treatment, especially if it renders excellent, predictable, and long-lasting results. CONCEPTS TO CONSIDER When root canal treatment has been completed, the immediate questions include: • Are a post and core required? • Is a cast or a prefabricated design preferred?

Propuesta de una clasificación para medir los defectos de extensión de dientes anteriores con tratamiento de conducto Classification Proposal to measure extension defects of endodontically treated anterior teeth

Abstract: SUMMARY A classification of the extension defects of endodontically anterior teeth is presented. This classification is based on the amount of remanent coronal tooth after an essential treatment has been done, such as: root canal therapy, removal of carious tissue, periodontal surgery whenever needed and tooth preparation either for the placement of a direct restoration material such as composite or a post and core and full crown restoration. This classification is based on 3 specific variables: supragingival remai ning coronal tooth structure or core height, diameter and root canal depth.