Showing papers on "Post and core published in 2002"
TL;DR: Within the limitations of this study, significantly higher failure loads were recorded for root canal treated teeth restored with quartz fiber posts, and Fractures that would allow repeated repair were observed in teeth restoredWith quartz fiber and glass fiber posts.
Abstract: Statement of Problem. Very little is known about the resistance to fracture of endodontically treated teeth restored with newly developed esthetic post systems. Purpose. This in vitro study compared the effect of 1 titanium and 3 esthetic post systems on the fracture resistance and fracture patterns of crowned, endodontically treated teeth. Material and Methods. A total of 40 recently extracted human maxillary canines with their crowns removed were endodontically treated. Four groups of 10 specimens were formed. Teeth were restored with titanium, quartz fiber, glass fiber, and zirconia posts and numbered as groups 1, 2, 3, and 4, respectively. All posts were cemented with Single Bond dental adhesive system and dual-polymerizing RelyX ARC adhesive resin cement. All teeth were restored with composite cores, and metal crowns were fabricated and cemented with glass ionomer cement. Each specimen was embedded in acrylic resin and then secured in a universal load-testing machine. A compressive load was applied at a 130-degree angle to the long axis of the tooth until fracture, at a crosshead speed of 1 mm/min. One-way analysis of variance and a Tukey test were used to determine the significance of the failure loads between groups ( P 2 test was conducted for evaluation of the mode of failure ( P Results. The mean failure loads (kg) were 66.95, 91.20, 75.90, and 78.91 for groups 1 to 4, respectively. Teeth restored with quartz fiber posts (group 2) exhibited significantly higher resistance to fracture ( P P >.05). Fractures that would allow repair of the tooth were observed in groups 2 and 3, whereas unrestorable, catastropic fractures were observed in groups 1 and 4 ( P Conclusion. Within the limitations of this study, significantly higher failure loads were recorded for root canal treated teeth restored with quartz fiber posts. Fractures that would allow repeated repair were observed in teeth restored with quartz fiber and glass fiber posts. J Prosthet Dent 2002; 87:431-7.
576 citations
TL;DR: It was confirmed that all simulated reconstructed teeth were more subject to stress in the cervical region, as the absence of a cervical ferrule was found to be a determining negative factor, giving rise to considerably higher stress levels.
Abstract: Statement of Problem. Following endodontic therapy, teeth need to be protected, particularly in the cervical region, where the majority of fractures occur. The likelihood of a fracture depends on the condition of the crown and the type of reconstruction performed. Purpose. This simulation study was designed to compare the effect of different corono-radicular reconstruction methods on stress transmission to dental tissues. Material and Methods. The study software performed stress analysis of complex structures by finite element analysis. Seven 3-dimensional models were created, each representing a tooth embedded in a bony medium. The following parameters affecting corono-radicular restoration were studied: 2 levels of coronal destruction, core materials, post materials when present, and absence of post. The 2 levels of coronal tissue loss were (1) total tissue loss of the coronal dentin and (2) partial tissue loss of the coronal dentin with 2-mm surviving dentin walls. Teeth with 2 different levels of tissue loss (first study parameter) were reconstructed by 4 different techniques: nickel chromium (NiCr) cast post and core, NiCr post and composite core combination, carbon fiber post and composite core combination, and composite restoration without post. A NiCr crown covered each of the models and received a 30° oblique occlusal load at a constant intensity of 100 N. The software computed the stresses (local tensile stress inducing cracks and compressive stress) for each of the models, comparing maximum intensity observed, localization, and concentration. Results. Whatever the type of stress (tensile or compressive), the greatest stress was observed in the cervical region, regardless of the model. Only tensile stresses potentially responsible for fractures were compared. Cervical tensile stresses exceeded 230 Pa in the absence of a ferrule and were less than 140 Pa when a ferrule was present. In the absence of a ferrule, the NiCr composite/post combination generated greater cervical stress (254 Pa) than the cast post and core (235 Pa). Results with a ferrule showed 92 Pa for the NiCr composite/post combination and 90.5 Pa for the cast post and core. In the presence of a ferrule, the tensile stress intensities generated by the composite restoration with no root canal post (139 Pa) were 51% greater than those generated by the NiCr/composite combination and approximately 26% greater than those generated by the composite/carbon combination. Conclusion. Within the limitations of this study, it was confirmed that all simulated reconstructed teeth were more subject to stress in the cervical region. The absence of a cervical ferrule was found to be a determining negative factor, giving rise to considerably higher stress levels. When no ferrule was present, the NiCr post/composite combination generated greater cervical stress than cast post and cores. Nevertheless, the peripheral ferrule seemed to cancel the mechanical effect of the reconstruction material on the intensity of the stresses. With a ferrule, the choice of reconstruction material had no impact on the level of cervical stress. The root canal post, the purpose of which is to protect the cervical region, was also shown to be beneficial even with sufficient residual coronal dentin. In the presence of a root canal post, cervical stress levels were lower than when no root canal post was present. Moreover, the higher the elasticity modulus, the lower the stress levels. (J Prosthet Dent 2002;88:442-8.)
226 citations
TL;DR: The results suggest that zirconia posts with ceramic cores can be recommended as an alternative to cast posts and cores and clinical trials are required to verify these in vitro results.
Abstract: Statement of Problem. Prefabricated metal and ceramic posts can be used with direct or indirect cores as an alternative to the conventional cast post and core. It is unclear how the fracture strength of zirconia posts with composite or ceramic cores and titanium posts with composite cores compares to the fracture strength of gold posts and cores after dynamic loading. Purpose. This study compared the fracture strength of endodontically treated, crowned maxillary incisors with limited ferrule length and different post-and-core systems after fatigue loading. Material and Methods. Sixty-four caries-free, human maxillary central incisors were divided into 4 groups. After root canal treatment, Group 1 was restored with titanium posts and composite cores, Group 2 with zirconia posts and composite cores, and Group 3 with zirconia posts and heat-pressed ceramic cores. Teeth restored with cast-on gold posts and cores served as the controls (Group 4). Teeth were prepared with a circumferential shoulder including a 1 to 2 mm ferrule; all posts were cemented with an adhesive resin cement, restored with complete-coverage crowns, and exposed to 1.2 million load cycles (30 N) in a computer-controlled chewing simulator. Simultaneous thermocycling between 5°C and 55°C was applied for 60 seconds with an intermediate pause of 12 seconds. All specimens that did not fracture during dynamic loading were loaded until fracture in a universal testing machine at a crosshead speed of 1.5 mm/min; loads were applied at an angle of 130 degrees at the incisal edge. Fracture loads (N) and modes (repairable or catastrophic) were recorded. The Kruskal-Wallis test was used to compare fracture loads among the 4 test groups. Analyses were conducted both with and without the specimens that failed during the chewing simulation. A Fisher exact test was performed to detect group differences in fracture modes. A significance level of P Results. The following survival rates were recorded after the chewing simulation: 93.8% (Group 1), 93.8% (Group 2), 100% (Group 3), and 87.5% (Group 4). The median fracture strengths for Groups 1 to 4 were 450 N, 503 N, 521 N, and 408 N, respectively. No significant differences were detected among the groups. The use of zirconia posts resulted in a nonsignificant lower number of catastrophic root fractures. Conclusion. Within the limitations of this study, the results suggest that zirconia posts with ceramic cores can be recommended as an alternative to cast posts and cores. If a chairside procedure is preferred, zirconia or titanium posts with composite cores can be used. Clinical trials are required to verify these in vitro results. (J Prosthet Dent 2002;87:438-45.)
216 citations
TL;DR: The literature suggests that the prognosis of root canal-treated teeth can be improved by sealing the canal and minimizing the leakage of oral fluids and bacteria into the periradicular areas as soon as possible after the completion ofRoot canal therapy.
Abstract: A review of the literature was performed to determine whether prompt placement of coronal restorations, including sealing and placement of posts and cores, can positively influence the long-term prognosis of teeth after root canal therapy. Both hand and MEDLINE searches were employed to identify peer-reviewed articles on radicular apical integrity after coronal restorations, especially where root canal space was used for post and core fabrication. A total of 41 articles published between 1969 and 1999 (the majority from the 1990s) were reviewed. The literature suggests that the prognosis of root canal-treated teeth can be improved by sealing the canal and minimizing the leakage of oral fluids and bacteria into the periradicular areas as soon as possible after the completion of root canal therapy.
183 citations
TL;DR: It was concluded that the preservation of both internal and external tooth structure is of utmost importance when restoring endodontically treated teeth.
140 citations
TL;DR: Within the limitations of this study, core stiffness did not affect the failure resistance of teeth restored with posts and cores and complete-coverage cast metal crowns.
Abstract: Statement of Problem. Dentin and core materials that substitute for missing dentin are dissimilar materials. A core material with a lower elastic modulus may deform more under applied stress and therefore result in reduced stress concentration at the core/dentin junction. Purpose. This in vitro study examined the effect of core stiffness on the fracture resistance and failure characteristics of a crowned, endodontically treated tooth under simulated occlusal load. Material and Methods. Forty extracted human mandibular premolars were divided equally into 4 groups and prepared for posts and cast crowns as follows: group 1=cast post and core, cast crown; group 2=preformed metal post, composite core, and cast crown; group 3=preformed metal post, amalgam core, and cast crown; and group 4 (control) = preformed metal post, no core, and cast crown. All prepared teeth had 2 mm of sound dentin on which the cemented crown rested. A continuous load (kg) was applied 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. Collected data were subjected to 1-way analysis of variance with the Welch modification to compare groups ( P Results. Failure loads for the 4 test groups were as follows: 98.1 ± 34.6 kg (group 1), 94.4 ± 41.8 kg (group 2), 105.5 ± 18.6 kg (group 3), and 101.1 ± 55.3 kg (group 4). No significant difference in failure load values was found among the 4 groups. The primary mode of failure (80%) in all groups was an oblique radicular fracture, either apical to the post or at the post level. Horizontal fracture of the root and post was found in groups 1, 2, and 3 (20%). Loosening of the crown, post, and core was found only in group 2(20%). Conclusion. Within the limitations of this study, core stiffness did not affect the failure resistance of teeth restored with posts and cores and complete-coverage cast metal crowns. The dominant pattern of failure was unrepairable root fracture. Only the composite core exhibited repairable fractures. (J Prosthet Dent 2002;88:302-6.)
83 citations
TL;DR: This case presents the clinical sequence of rehabilitation of upper anterior primary teeth, where endodontic treatments were done, followed by the construction of root post using polyethylene ribbon fibers and the fabrication of crowns composed of resin.
Abstract: The early loss of the anterior primary teeth can cause problems in phonation, development of the maxilla and is related to deleterious habits. This case presents the clinical sequence of rehabilitation of upper anterior primary teeth, where endodontic treatments were done. This was followed by the construction of root post using polyethylene ribbon fibers and the fabrication of crowns composed of resin.
41 citations
TL;DR: Results indicated that the permanently cemented, prefabricated post and core produced the best seal (p < 0.01); leakage was significantly greater with the temporary post crown and was similar to that of a positive control group.
35 citations
Journal Article•
TL;DR: The low strength values obtained for glass-ionomer cement in combination with threaded retention pins makes this combination a poor choice for core buildup.
Abstract: Objective: In this in vitro study, the strength of several core and post-and-core systems was compared. A second aim was to compare the strength of posts and cores on root-filled teeth with that of cores on vital teeth. The failure modes of the core and post-and-core systems were also studied. Method and materials: For root-filled teeth, Composipost carbon fiber dowels and gold alloy posts and cores were tested. For vital teeth, glass-ionomer cement with threaded parapulpal retention pins, resin composite with threaded parapulpal retention pins, and gold alloy with parallel parapulpal pins were tested. Specimens were tested in a Zwick universal material-testing machine. Results: A significant variation in strength was found among core systems of cast gold, resin composite, and glass-ionomer cement constructed on vital teeth. The strength of the systems constructed on root-filled teeth did not vary significantly. The mode of failure varied, depending on the core or post-and-core material. Conclusion: Composipost posts and cores and cast gold posts and cores were equivalent in strength and did not vary significantly from gold cores constructed on vital teeth. The low strength values obtained for glass-ionomer cement in combination with threaded retention pins makes this combination a poor choice for core buildup.
27 citations
Journal Article•
TL;DR: Adhesively luted all-ceramic cores on zirconia posts offer a viable alternative to the conventional pressed technique and demonstrates the load dependence of the deflection.
Abstract: PURPOSE All-ceramic post-and-core restorations offer a number of advantages compared with systems that use metal cores. In certain clinical cases, however, fractures at the junction between the post and the core have been reported. The objective is therefore to improve the strength between the post and the core. MATERIALS AND METHODS Three different methods were used to fabricate all-ceramic post-and-core restorations: pressing IPS Empress cores directly to CosmoPost zirconia posts, adhesively luting IPS Empress cores to CosmoPost zirconia posts, and Celay milling In-Ceram zirconia blanks to one-piece post-and-core restorations. Ten restorations were prepared with each of the three methods. The post-and-core complexes were tested to failure with the load applied perpendicular to the post axis. The load and deflection at fracture were recorded. RESULTS The highest breaking load and highest deflection were recorded for the luting technique, with values of 25.3 N and 394 microns, respectively. The corresponding values for the pressed cores and the milled zirconia cores were 22 N and 301 microns, and 13 N and 160 microns. All differences were statistically significant at P < .05. Regarding the load dependence of the deflection, the luted cores again demonstrated the highest mean value, with 15.5 microns/N, while this value was 13.6 microns/N and 13 microns/N for the pressed-on and milled cores, respectively. These differences were not statistically significant. CONCLUSION Adhesively luted all-ceramic cores on zirconia posts offer a viable alternative to the conventional pressed technique.
25 citations
Journal Article•
TL;DR: The restoration for an endodontically treated tooth should be conservative and should not increase horizontal and vertical forces, and a bondable polyethylene ribbon was used as a post-and-core build-up material.
Abstract: The restoration for an endodontically treated tooth should be conservative and should not increase horizontal and vertical forces. A recently developed bondable reinforcement fiber is reported to be an alternative to conventional post materials because of its esthetic qualities, mechanical properties, and the neutral color of the reinforcing material. This article describes the treatment of one patient, in whom a bondable polyethylene ribbon was used as a post-and-core build-up material.
TL;DR: This tip presents a modification of the technique described by Priest and Goerig, which ensures the presence of adequate cement space for the final restoration.
Abstract: Fabrication of the post and core generally precedes fabrication of the final restoration. Several techniques have been described for making a post and core pattern with autopolymerzing acrylic resin or wax to retrofit an existing crown.1-5 This tip presents a modification of the technique described by Priest and Goerig.4 In our experience, the described procedure is easy and predictable, and it ensures the presence of adequate cement space for the final restoration.
TL;DR: This procedure requires the placement of an opaque layer of ceramic on the core, thereby moving such a layer 0.3 to 0.5 mm more deeply from the surface of the restoration, which allows more depth and translucence to the crown, as light penetrates further into the crown.
Abstract: This article presents a technique to enhance the optic qualities of all-ceramic crowns when placed over a cast post and core. An opaque layer is necessary over a metal structure, such as a cast core, to reduce light absorption and increase the reflectance of the metal. The desired effect is to raise the value of the core in order to approach the optic qualities of dentin. However, the problem of reflectance is fully eliminated by the use of an opaque layer of ceramic. The translucence of a ceramic crown may not be limited by the use of opaque material under the crown. This procedure requires the placement of an opaque layer of ceramic on the core, thereby moving such a layer 0.3 to 0.5 mm more deeply from the surface of the restoration. This allows more depth and translucence to the crown, as light penetrates further into the crown.
TL;DR: With the 'greying' of the population there are increased demands on dentists to restore structurally compromised teeth, and increasing expectations of the performance of these restorations.
Abstract: Background: This article addresses the difficult clinical problem of restoration of endodontically treated posterior teeth, where there is nothing left of the clinical crown.
Methods: A step by step procedure, including instrumentation and materials and a new impression technique, is described in detail, with clinical photographs.
Results: This technique results in the fabrication of a robust and extremely retentive post and core on which to place fixed prosthodontic restorations.
Conclusions: The author has placed over 600 restorations of this type over a five year period, without any reported failures. With the |Dsgreying|DS of the population there are increased demands on dentists to restore structurally compromised teeth, and increasing expectations of the performance of these restorations. This technique is offered as a superior alternative to conventional post and core constructions methods.
Patent•
29 Jul 2002
TL;DR: In this article, a post and core assembly for the implantation of a dental prosthesis is presented, which allows for an infinite number of precise lengths and angular deviations between the post and the core to precisely align a prosthesis with existing teeth/prostheses without delays in fabrication outside of the dentist's office.
Abstract: A novel post and core assembly for the implantation of a dental prosthesis is set forth in the present invention. Comprised of separate post and core elements of a laser weldable material, the assembly allows for an infinite number of precise lengths and angular deviation between the post and core to precisely align a prosthesis with existing teeth/prostheses without delays in fabrication outside of the dentist's office, as is typically required in prior art assemblies. The post and/or core may be cut to the desired length and angle and welded, on site, with a minimal requirement for fabrication equipment.
Dissertation•
01 Jan 2002
Journal Article•
Journal Article•
TL;DR: The custom-fabricated Celay post-core could be a choice for clinical use in endodontically treated tooth when the final restoration is an all-ceramic crown and the preparation has a 2.0 mm dentine ferrule.
Abstract: OBJECTIVE The purpose of this study is to compare the fracture strengths of custom-fabricated Celay all-ceramic post-core, custom cast metal post-core, and prefabricated stainless steel post (Parapost) plus composite resin core with or without a 2.0 mm dentine ferrule. METHODS A total of 60 recently extracted human maxillary central incisors were endodontically treated and divided into five groups of 12. They were given the following treatments: Group A: Celay ceramic post-core with 2.0 mm dentine ferrule, Group B: Celay ceramic post-core with no dentine ferrule, Group C: cast metal post-core with 2.0 mm dentine ferrule, Group D: cast metal post-core with no dentine ferrule, and Group E: prefabricated post and composite core with 2.0 mm dentine ferrule. All specimens were stored at 100% humidity at room temperature for 30 days before testing. Each specimen was in a special jig at a 45 degrees angle to the long axis and subjected to a load on MTS 810 universal material testing machine until failure, with crosshead speed of 0.02 cm/min. Analysis of variance followed by the Newman-Keuls pairwise multiple comparison test was used to compare the results of the groups tested. RESULTS There was a statistically significant difference between five groups (P < 0.01). Celay ceramic post-core with 2.0 mm dentine ferrule (758.35 N +/- 119.26 N) and cast metal post-core with 2.0 mm dentine ferrule (756.63 N +/- 166.22 N) had a significantly larger mean failure threshold for fracture than the other three groups which had no significant difference between each other. There was a statistically significant difference between the fracture resistance of Celay post-core restored teeth with and without 2.0 mm dentine ferrule. CONCLUSION The custom-fabricated Celay post-core could be a choice for clinical use in endodontically treated tooth when the final restoration is an all-ceramic crown and the preparation has a 2.0 mm dentine ferrule.
TL;DR: Good esthetic results and improvements in the oral soft tissue in cases of dental metal allergy can be achieved using the newly developed all-ceramic post and core.
Abstract: Purpose : A study was done to investigate the use of a newly developed esthetically and mechanically superior all-ceramic zirconium post and core system (CosmoPost®, Ivoclar, Liechtenstein). Fabrication techniques and clinical cases are discussed.Materials and Methods : CosmoPost®s are cylindrical conical-shaped posts made of ZrO2-TZP and are marketed with corresponding rotary drilling and trimming instruments. The ceramic cores can be fabricated by either direct or indirect methods.Results : The authors have used zirconium all-ceramic posts and cores since 1997 to improve esthetics and to treat cases of dental metal allergy. Results at achieving natural tooth color and translucency have been evaluated as excellent. No failures of crowns, post and cores have been observed up to the present.Conclusion : Good esthetic results and improvements in the oral soft tissue in cases of dental metal allergy can be achieved using the newly developed all-ceramic post and core.