Cast Metal Core Research Articles

A clinical case of restoration of the destroyed crown part of the tooth complicated by changes in the bifurcation area

The destruction of the tooth crown should be regarded as the cause leading over time to the disruption of the morphofunctional unity of the dentition and pathological condition of the entire dentoalveolar system. Untimely treatment of defects of hard tooth tissues leads to functional disorganization of the dentoalveolar system. The most eliminated defects are those of crowns of teeth determining the quality of aesthetics, phonetics, functions of biting and chewing. The destruction of the tooth crowns, which do not cause significant disruption of the above functions, are painless and almost asymptomatic. In such cases, deformation of the dentition and occlusion, dysfunction of masticatory muscles and temporomandibular joints as well as the development of pathological changes in periodontium occur slowly. Of great importance are the early diagnosis of pathological reconstruction of dentoalveolar system and the knowledge of pathogenesis of possible complications after the extraction of the teeth that determine the indications for prophylactic orthopedic dental treatment. The article presents a clinical case of restoration of destructed tooth crown 3.6 complicated by changes in bifurcation area. The patient underwent coronary-radicular separation with the use of cast metal cores, which allowed restoration of the sufficient size of the stump, function and anatomical shape of the tooth and hence the unity of dental arch.

Fracture resistance of metal-ceramic crown copings cemented to two types of intra-radicular posts

Abstract Introduction Endodontically treated teeth are more susceptible to root fracture than vital teeth. In order to reduce the risk of fracture, the use of intra-radicular posts and crowns is indicated. However, their own fracture resistance remains unclear. Objective To analyze the behavior of metal-ceramic crown copings cemented to two types of intra-radicular posts under tensile stress. Material and method Sixteen metal-ceramic crown copings cemented with zinc phosphate cement to cast metal posts and cores (group 1, n = 8) or with self-adhesive resin cement to glass-fiber posts rebased with composite resin (group 2, n = 8) were subjected to tensile testing after endodontic treatment and standardized preparation. Failure occurred when the crown coping and/or post-core assembly fractured and/or detached. Result In group 1, after the application of a mean tensile load of 46.83 N, 7 crown copings and metal cores separated as a whole, while in 1 specimen the coping detached from the metal core. In group 2, a mean tensile load of 127.68 N resulted in glass-fiber post fracture, and in 1 case the entire crown-post-core assembly was detached. Tensile strength differed significantly between the two groups (p = 0.0085). Conclusion Our findings suggest that metal-ceramic crown copings cemented with self-adhesive resin cement show strong adhesion to composite resin cores associated with glass-fiber posts, thus providing a safe alternative to the use of cast metal posts and cores.

純TiおよびTi-6Al-4Vの既製ポストとしての適合性 : 第1報 機械的性質ならびにメタルコア鋳接性

純TiおよびTi-6Al-4Vの既製ポストとしての適合性 : 第1報 機械的性質ならびにメタルコア鋳接性

Coronal Microleakage of Teeth Restored with Cast Posts and Cores Cemented with Four Different Luting Agents after Thermocycling.

The apical seal provided by a root canal filling may be breached via coronal leakage. This study aimed to compare the teeth restored with custom-made cast metal posts and cores cemented with different luting agents in terms of coronal microleakage after thermocycling. This in vitro study was conducted on 32 extracted single-canal teeth. Root canals were prepared by step-back technique and filled with gutta percha and sealer. The coronal 7mm of gutta percha was removed, and post space was prepared using peeso reamers #2 and #3 consecutively. After fabricating the acrylic resin patterns of the posts and cores, they were cast using Ni-Cr metal alloy. The specimens were divided into 4 groups in which the castings were cemented using one of the following luting agents: zinc phosphate (ZP), glass ionomer (GI), Panavia F 2.0, and Speed CEM. After cementation, the teeth were immersed in distilled water and incubated for 7days. Then, the teeth were subjected to thermocycling, immersed in silver nitrate for 6hours, and finally sectioned. The degree of dye penetration into the coronal part of the specimens was measured using a stereomicroscope. Data were analyzed using Kruskal-Wallis and Mann-Whitey U tests with significance level of 0.05. The median microleakage in ZP, Speed CEM, GI, and Panavia were 171.89, 114.76, 26.51, and 20.02μm, respectively. Pairwise comparisons among GI and ZP, GI, and Speed CEM, ZP and Panavia, ZP and Speed CEM, and Panavia and Speed CEM groups yielded significant differences (p<0.05). Complete coronal seal was not achieved with any of the luting agents. The highest and the lowest degree of microleakage was yielded by ZP and Panavia luting agents, respectively.

Fracture Strength of Flared Root Canals Restored with Different Post Systems.

Objective:To evaluate the fracture resistance of different intra-radicular post systems in flared root canals.Methods:Sixty human canines were used. The coronal portion was removed and the root length was standardized at 17 mm. Canals were prepared and filled with gutta-percha/AH Plus sealer. Roots were embedded in self-polymerising acrylic resin blocks. According to the material used, the teeth were randomly divided into three groups (n=20): glass fibre post (GFP): GFP and Z350 resin composite core; pre-fabricated metal post (PMP): PMP and Z350 resin composite core; and cast metal core (CMC): CMC with silver-tin alloy. Coronal reconstruction involved fabrication of metal copings. Samples were submitted to mechanical compression testing at 45º in a universal test machine. Fracture pattern was evaluated under a stereoscope. The fracture strength values were submitted to one-way analysis of variance (ANOVA) and Tukey tests (α=0.05).Results:There was no statistically significant difference between the resistance values among groups (P=0.193). With regard to fracture pattern, GFP showed 55% and PMP 45% of Type I fractures, which considered repairable or favourable, whereas MCC presented 50% of Type V, which was considered irreparable or unfavourable.Conclusion:Glass fibre and pre-fabricated metal posts have good fracture resistance to compression and may be used for restoring flared root canals, since they presented fractures mainly involving the filling core, thus facilitating later repair.

Fracture Strength of Flared Root Canals Restored with Different Post Systems

Objective To evaluate the fracture resistance of different intra-radicular post systems in flared root canals. Methods Sixty human canines were used. The coronal portion was removed and the root length was standardized at 17 mm. Canals were prepared and filled with gutta-percha/AH Plus sealer. Roots were embedded in self-polymerising acrylic resin blocks. According to the material used, the teeth were randomly divided into three groups (n=20): glass fibre post (GFP): GFP and Z350 resin composite core; pre-fabricated metal post (PMP): PMP and Z350 resin composite core; and cast metal core (CMC): CMC with silver-tin alloy. Coronal reconstruction involved fabrication of metal copings. Samples were submitted to mechanical compression testing at 45o in a universal test machine. Fracture pattern was evaluated under a stereoscope. The fracture strength values were submitted to one-way analysis of variance (ANOVA) and Tukey tests (α=0.05). Results There was no statistically significant difference between the resistance values among groups (P=0.193). With regard to fracture pattern, GFP showed 55% and PMP 45% of Type I fractures, which considered repairable or favourable, whereas MCC presented 50% of Type V, which was considered irreparable or unfavourable. Conclusion Glass fibre and pre-fabricated metal posts have good fracture resistance to compression and may be used for restoring flared root canals, since they presented fractures mainly involving the filling core, thus facilitating later repair.

Radiographic analysis of 1000 cast posts in Sergipe state, Brazil

Abstract Introduction Endodontically treated teeth with extensive coronary destruction require posts and cores to enable prosthetic restoration. Despite the increasing use of prefabricated posts, cast metal posts and cores are still widely used. The quality of the latter is important for the longevity of restorative treatment, and failure can occur if the fundamental principles are not followed. Objective To radiographically evaluate the prosthetic principles of 1000 cast metal post-and-core restorations performed in single-rooted teeth and their coherence with the principles used for their confection. Material and method Digital periapical radiographs of 1000 endodontically treated, single-rooted teeth with cast metal posts and cores were selected from the collection of a radiology clinic (Centro de Imagem, Aracaju/SE, Brazil). The images were analyzed using a measurement software (ImageJ, USA) in accordance with the fundamental prosthetic principles: length and diameter of the post, ratio between post and bone crest, contiguity of post to the root canal, gap between post and the remaining root canal filling, amount of remaining root canal filling, and absence of periapical lesion. The data were qualitatively analyzed, classified into ideal and not ideal, and submitted to the chi-square test (α=0.05). Result Only 6.7% of the cast metal posts analyzed were satisfactorily fabricated. Conclusion Many prosthetic criteria are neglected during the manufacturing of cast metal post and cores, resulting in inadequate work that may compromise the longevity of restorative treatments.

Endocrown: a conservative approach

ABSTRACT The purpose of this clinical case description article was to present the planning sequence, indication, treatment and performance to obtain a crown of the Endocrown type. This clinical case description article illustrates a therapeutic option for functional and esthetic rehabilitation of a devitalized mandibular molar, presenting a small amount of remaining coronal tooth structure, by means of cementing a pure porcelain crown of the Endocrown type (Adhesive Endodontic Crown). A 39-year-old woman presented to the Graduate clinic of the Bauru Dental School (FOB), University of São Paulo (USP), with the complaint that tooth #36 had an extensive and unsatisfactory composite resin restoration. The lithium disilicate-based system of monolithic porcelain was used with the lost wax technique. This therapy promoted the stability and retention of the indirect restoration, without the need for performing reconstruction of the above mentioned tooth, either by means of a cast metal core or reconstruction with intracanal post, thereby reducing the treatment time. After the tooth preparation, the provisional restoration was done with acrylic resin to determine if the retention and stability of the remaining tooth was adequate to receive the indirect Endocrown restoration. The characteristics of the internal and external walls of the dental remnants, cervical termination, impression-taking, laboratory stages and adhesive cementation will be discussed. The major advantage of indicating an endocrown is the use of the dental remnants itself, particularly the pulp chamber, to promote retention and stability in cases without adequate height for performing complete dental and crown reconstruction.KeywordsAdhesive endodontic crown; Devitalized tooth; Lithium dissilicate.

Mechanical properties of flared root canals restored with fiber post and chemically activated resin: study using push-out bond strength and fracture load tests

This study aimed to evaluate the fracture load and push-out bond strength of flared root canals restored with different procedures, including a technique with a fiber post and a chemically activated resin composite. Eighty human canines were selected and treated endodontically. Two methodologies were used: push-out and fracture load. The teeth were divided into four groups: Cast metal core (CMC); PAN (direct anatomic post); PAC (fiber post and accessory posts); and PE (fiber post with chemically activated resin composite). For the fracture load test, the samples were submitted to load application in a universal testing machine. The fracture mode was evaluated visually. Forty other samples were submitted to the push-out test. The fracture load (n = 10) and the bond strength (n = 10) were analyzed by analysis of variance and Tukey tests (α < 0.05). CMC presented the highest fracture load (p < 0.05), and no significant differences were observed in the fracture load values for Groups PAN, PAC, and PE. CMC presented 90% of unfavorable failures; PAN and PAC, the remaining 10% of these failures. PE presented only favorable failures. PAC presented lower push-out bond strength values. The fracture load for CMC procedure was higher than that of the others, but presented 90% unfavorable fractures, indicating the use of any of the glass fiber post techniques evaluated for restoring flared root canals due to favorable fracture modes.

Masking Conventional Metallic Cast Post for Enhancing Esthetics

ABSTRACTLoss of tooth structure occurs due to caries, endodontic treatment, or fracture caused by trauma; restoring these teeth is difficult task for a clinician. Post and core is an option for teeth when excessive tooth structure is lost and teeth need to be restored with crown and bridge procedure. They can be prefabricated post with composite built up or a one-piece custom-made post. The custom-made cast metal post and core have disadvantage due to their color that imparts grayish hue to overlying ceramic restorations. Masking the metal core can enhance the esthetic of all ceramic restorations that are placed over the cast post and core. A case report is being presented where the metallic core was masked with ceramic built up on labial surface of metal core.How to cite this articleShah NP, Gaikwad AM, Ram SM, Nadgere JB. Masking Conventional Metallic Cast Post for Enhancing Esthetics. J Contemp Dent 2016;6(1):85-89.

Effect of the action of diamond burs with high speed on the tensile strength of cores cemented with zinc phosphate at different preparation times

Objective: To know the finishing effect, in order to be able to safely proceed with the cores preparation in the daily clinic, without compromising the prosthetic restoration longevity. Methods: This study used 48 human single-rooted premolars, which after the section of its crowns, were endodontically treated, and its root canal prepared 8 mm deep to receive cores casting in cobalt-chrome alloy. Cementing was made with zinc phosphate and the tensile test performed at different preparation times: G1 - without re-preparation after cementation (control); G2 - re-prepared 24 hours after cementation, and G3 - re-prepared 15 minutes after cementation. Results: Statistical analysis showed no significant difference in the tensile strength values in the different groups (p = 0.233), in other words, the core re-preparation 15 minutes or 24 hours after the cementation caused no significant reduction in tensile strength between the core and the root remaining when using the zinc phosphate cement. Conclusion: The metallic core re-preparation cast 15 minutes or 24 hours after cementation caused no significant reduction in tensile strength between the cast metallic core and the root remaining, although in absolute values there was an important difference.

Influence of Temporary Cements on the Bond Strength of Self-Adhesive Cement to the Metal Coronal Substrate.

This research evaluated the influence of temporary cements (eugenol-containing [EC] or eugenol-free [EF]) on the tensile strength of Ni-Cr copings fixed with self-adhesive resin cement to the metal coronal substrate. Thirty-six temporary crowns were divided into 4 groups (n=9) according to the temporary cements: Provy, Dentsply (eugenol-containing), Temp Cem, Vigodent (eugenol-containing), RelyX Temp NE, 3M ESPE (eugenol-free) and Temp Bond NE, Kerr Corp (eugenol-free). After 24 h of temporary cementation, tensile strength tests were performed in a universal testing machine at a crosshead speed of 0.5 mm/min and 1 kN (100 kgf) load cell. Afterwards, the cast metal cores were cleaned by scraping with curettes and air jet. Thirty-six Ni-Cr copings were cemented to the cast metal cores with self-adhesive resin cement (RelyX U200, 3M ESPE). Tensile strength tests were performed again. In the temporary cementation, Temp Bond NE (12.91 ± 2.54) and Temp Cem (12.22 ± 2.96) presented the highest values of tensile strength and were statistically similar to each other (p>0.05). Statistically significant difference (p<0.05) was observed only between Provy (164.44 ± 31.23) and Temp Bond NE (88.48 ± 21.83) after cementation of Ni-Cr copings with self-adhesive resin cement. In addition, Temp Cem (120.68 ± 48.27) and RelyX Temp NE (103.04 ± 26.09) showed intermediate tensile strength values. In conclusion, the Provy eugenol-containing temporary cement was associated with the highest bond strength among the resin cements when Ni-Cr copings were cemented to cast metal cores. However, the eugenol cannot be considered a determining factor in increased bond strength, since the other tested cements (1 eugenol-containing and 2 eugenol-free) were similar.

Evaluation of Effect by Different Surface Treatment Agents on Retention of Custom Made Cast Metal Post and Prefabricated Glass Fibre Post-A Comparative Study

AbstractPosts are widely used for restoring endodontically treated teeth with insufficient coronal tooth structure. Custom made cast metal post and core systems have a long history of successful use due to their superior physical properties. Prefabricated post systems have recently become more popular because they can provide satisfactory results, while saving time and reducing costs. Materials and Method: Post spaces were prepared in 60 extracted caries free teeth, and divided into two main groups of 30 teeth each for cast metal and glass fibre posts. These groups were further divided into 3 subgroups of 10 specimens each I) Control group without any surface treatment, II) Specimens treated with 57% ethanol, III) Specimens air abraded with 50um air borne alumina particles. Teeth were mounted in acrylic blocks prepared from a specially fabricated metal device. Posts were luted in the prepared post spaces with glass ionomer luting cement. Retentive strength was tested by Universal testing machine at 2mm/min crosshead speed. Results: Sand blasting of cast metal posts showed more significant improvement in retention compared to both control group and ethyl alcohol treated groups. In case of glass fibre posts, sand blasting significantly improved its retention compared to control group but no significant difference was observed between control and ethyl alcohol treated groups. There was also no significant difference between ethyl alcohol treated and sand blasted group. Conclusion: It was concluded that, sand blasting is an effective method to improve retention of both cast metal and glass fibre posts.

Restoration of endodontically treated anterior teeth with cast metallic post or prefabricated fibre post placement: 2 case reports and critical literature review

With a wide variety of post systems and materials available for the restoration of lost tooth structure of endodontically treated teeth, the clinical decision of which to use constitutes a challenge to dental practitioners. Cast metal post and cores are widely used for restoring endodontically treated teeth with extensive loss of coronal tooth structure and to retain metal-ceramic crowns. When dental aesthetics is of primary concern, the selection of the underlying restorative material becomes an important factor to consider. The fibre-reinforced posts combined with all-ceramic crowns offer a highly aesthetic outcome in anterior region restorations, but long-term evaluation is necessary in order to assess their clinical performance and longevity. The purpose of this paper was to present and compare 2 restorative options with regard to materials (cast metallic post and core versus prefabricated fibre post and composite resin core) for the prosthetic rehabilitation of cases with inadequate aesthetic appearance or fractured maxillary anterior teeth. Furthermore, the article reviews the main indications, advantages, and disadvantages from the use of the 2 post types combined with the final restorations, in order to allow the dental practitioner make the selection of appropriate restorative materials.

Evaluation of the fracture resistance of remaining thin-walled roots restored with different post systems

The purpose of this work was evaluating the fracture strength of bovine roots weakened experimentally, restored with two different techniques: internal reinforcement of root canal walls with composite resin and a cast metal post and core or anatomic post (glass fiber post associated with composite resin). Thirty bovine lower central incisive were selected and transversally sectioned, remaining 14 mm of root in order to approximate to the human maxillary central incisive. A sequence of standardized wear was used to weak the root until the walls remaining achieved from 0.5 to 0.7 mm of thickness at the cervical edge. Two groups were separated randomly (n=15) in order to test the roots reinforced with composite resin associated with cast metal post and core (CMP), or roots restored with composite resin associated to the glass fiber post (GFP). The test were applied in a Universal Test Machine (EMIC) with tangential compressive loading focused on the lingual face of core in an angle of 135° with the long axis of the tooth at a crosshead speed of 0.5 mm/min until failure occurred. The results showed that the fracture strength of remaining roots with weakened walls was influenced by the restorative technique, and the higher values of strength fractures were observed in the group of roots reinforced by composite resin associated with CMP (p&lt;0.001) when compared to the group of roots restored with anatomic post.

Stress pattern generated by different post and core material combinations: A photoelastic study

To analyze the effect of different combinations of post and core materials on stress distribution in dentin of an endodontically treated tooth. This was an experimental stress analysis study. Models were made in photoelastic material, i.e., epoxy resin. Different combinations of post and core materials used were: Glass fiber post with composite core, stainless steel post with composite core, and cast metal post and core. Stresses generated were frozen, models were sliced and viewed under circular polariscope, and photographs were taken. Stress was calculated by counting the number of fringes. For the combination of glass fiber post with composite core, the shear stresses calculated were 1.196, 1.196, and 2.898 MPa in the apical, mid-root, and cervical region, respectively. For the combination of stainless steel post with composite core, the apical, mid-root and cervical stresses were 1.534, 0.511, and 2.557 MPa, respectively. For cast metal post and core, the apical, mid-root, and cervical stresses were 0.852, 0.511, and 1.534 MPa, respectively. The cervical region of the teeth is subjected to the highest stresses irrespective of the material used. The stainless steel post with the composite core generated the highest stress concentration in different regions. A glass fiber post generated a uniform stress distribution. A cast metal post and core combination generated lesser stress than the other combinations. The vast difference in the elastic modulus of the restorative materials can lead to nonuniform stress distribution and concentration of stresses in different areas which can have deleterious effect on the survival of already compromised teeth and restoration. Such combinations should be avoided and the material which has an elastic modulus close to that of dentin should be preferred.

Split Cast Metal Post and Core

The best plan for success is to begin with the end in mind. It generally is agreed that the successful treatment of a badly broken down tooth with pulpal disease depends not only good endodontic therapy, but also on good prosthetic reconstruction of the tooth after endodontic therapy. The primary purpose of the post is to retain a core that can be used to retain definitive prostheses. A post and core help prevent coronal fractures when the remaining coronal structure is very thin after tooth preparation. When a substantial amount of coronal structure is lost a cast post and core is indicated. In this clinical report the root canal treated left mandibular first molar is restored with split cast metal post and core design using the direct technique for the fabrication of the post and core pattern using the autopolymerizing acrylic resin material and then further casted in the laboratory using the base metal alloy.

In vitro evaluation of glass fiber post

Statement of problem: Techniques and recommendations for the restoration of endodontically treated teeth have changed from the use of custom cast metal post and core system to glass fiber-reinforced (GFRC) post and composite core system. Has this latest prefabricated glass fiber reinforced post and composite core system increased the fracture resistance of teeth and reduced the incidence of unrestorable root fractures. Purpose: The purpose of this study was to evaluate the incidence of root fracture and mode of failure of endodontically treated teeth restored with two different post and core systems. Material and Methods: Forty maxillary central incisors were randomly divided into two groups. (n=20). All teeth received endodontic treatment. First group was restored with custom cast post and core system. Second group was restored with glass fiber post and composite core system. In Both the groups posts were cemented with adhesive resin cement. Compressive load was applied at an angle of 130 to the long axis of teeth at a cross head speed of 1 mm/min until fracture occurred. Data were analyzed with student “t” test P<.001. Results: The mean value for fracture resistance was (331.4025) N in Group -I Custom cast Ni-Cr post and core and (237.0625) N in Group -II Glass fiber reinforced post and composite core system. Students “t” test shows the significant difference in fracture resistance of two groups. Conclusion: This study showed that the incidence of root fracture was significantly higher in custom cast Ni-Cr post and core system than glass fiber post and composite core system. A more favourable mode of failure was observed in teeth restored with Group II glass fiber post system. Key words:Post-and-core technique, glass fiber post, cast post and-core system, fracture resistance, endodontically treated teeth.

Fracture resistance of three post and core systems in endodontically treated teeth restored with all-ceramic crowns

The restoration of endodontically treated teeth requires the fabrication of a post and core to provide retention and support for the final crowns. The objective of this study was to compare the fracture resistance of endodontically treated teeth restored with glass fiber post and composite resin cores, customized zirconia posts, and cast metal post and cores. A total of 40 human extracted mandibular first premolars were used for the study. The teeth were randomly divided into four groups. Group A represented a control group that did not receive any posts and was filled with core material only; Group B comprised cast metal posts and cores; Group C comprised custom milled zirconia posts and cores; and Group D comprised glass fiber posts. All groups were prepared to receive all ceramic crowns. All samples were subjected to compressive testing with an Instron machine (Universal Testing Machine) and fracture loads and failure patterns were analyzed. The findings indicated a statistically significant difference between the failure loads in the groups studied. The mean load required to fracture the zirconia custom posts was higher (765.1±48.5N) than the fiber posts and the cast posts and cores (P<0.001). The fiber posts resisted a mean load of 561.4±37.2N which was higher than the cast posts and cores. The control group revealed the lowest value of fracture resistance. Within the limitations of this study, it can be concluded that customized zirconia posts and cores resisted a higher mean load (765.1+48.5) when compared with other post and core systems. Failure patterns within this group revealed catastrophic failure, but the failure loads were much higher than the average occlusal load.

Influence of core materials in the microleakage of cast crowns

Endodontically treated teeth can be restored with prosthetic crowns over cast metal cores or prefabricated posts with composite resin cores. Prosthetic failure is frequently observed possibly due to microleakage. To verify the influence of the core materials in the microleakage of cast crowns, this research studied three experimental conditions: (a) teeth with partial dental remaining core with prefabricated post and partial composite resin cores, (b) teeth with cast metal posts/cores, and (c) teeth with prefabricated posts and composite resin cores. Teeth preparations were standardized, duplicated and the crowns were made in NiCr alloy, which were cemented with zinc phosphate cement. The specimens were submitted to thermocycling and mechanical stresses. They were immerged in a 0,05% aqueous solution of basic fuchsin for 8 hours during 3 days. The crowns were sliced buccal-lingually, and their microleakage was evaluated by glass magnification, according to a score scale. There was no statistical difference between conditions (a) and (c). Microleakage at cervical region of axial wall was observed in both cases. Condition (b) showed higher microleakage, which reached medium third of axial wall.