Effect of different post materials and designs on upper central tooth torque and intrusion load: A finite element analysis study.

PURPOSES: The aim of this study was to examine the effects of post material type and the presence of ferrules on the torque and intrusion load of the upper central tooth using finite element analysis. METHODS: The upper central tooth and surrounding tissues (cortical bone, cancellous bone, and periodontal ligament) were modelled in three dimensions using the Spaceclaim software. Five simulated models (SM) different modifications were made to this main model: metal cast post (SM1) and glass fiber post-core with zirconium crown and without a ferrule (SM2), metal cast (SM3) post and glass fiber post with a ferrule and zirconium crown (SM4) and only zirconium crown (SM5). In all five simulations, in order to simulate lingual root torque movement, a total load of 40 grams was applied to the bracket slot as 20 grams of force couples and in order to simulate intrusion movement, a load of 40 grams was applied to the superior wall of the bracket slot. The stress caused by the applied loads on the root surfaces was determined using finite element analysis. Maximum principal stress (MPS) value was used in the comparison. RESULTS: The highest root surface MPS values for both intrusion and torque loads belonged to SM2 (3.864 and 0.379MPa, respectively). The presence of ferrules in both intrusion and torque loads reduced the stress by approximately half (from 3.864 to 2.004MPa). In all five models, the radicular area with higher stress was located in the cervical third on the lingual surface when both torque and intrusion loads were applied. CONCLUSION: The amount and localization of stress was affected by the type of post material. The variation in stress values between the materials remains within a safe range (0.099 and 3.87MPa), making both materials suitable for use under orthodontic forces.

Is a Pre-Existent Cone-Beam Computed Tomography Able to Detect Metal Dental Posts?

(1) Background: In this study, the efficacy of cone-beam computed tomography (CBCT) in detecting dental posts was compared to periapical radiography. (2) Methods: A retrospective evaluation of 53 patients' periapical radiographs and CBCT images was performed. The presence and type of the intra-canal dental post were initially determined on the periapical images (PA) radiographs' examination and were then compared to the observer's ability to detect the dental post on a CBCT image. The effect of the post's type (metal cast or prefabricated) on its detection on CBCT images was determined. (3) Results: 10.5% of teeth that were identified as having a post on a PA radiograph were not identified as having a post on the CBCT examination (p < 0.05). Approximately 17.6% of teeth that were identified as not having a post on a PA radiograph were identified as having a post on the CBCT examination (p < 0.05). Moreover, 16.3% and 50% of teeth with a prefabricated or cast posts on PA radiographs were falsely identified on the CBCT examination, respectively (p < 0.05). (4) Conclusions: A CBCT image is an insufficient tool for the identification of metal prefabricated and cast posts. A PA image is the recommended radiographic tool for achieving information about the post-endodontic restoration status of teeth candidates for endodontic retreatment in patients with a former CBCT scan.

Factors Influencing Vertical Radicular Fractures in Teeth Supported by Metallic Dental Core: A Scoping Review.

Purpose: The aim of this work is to conduct a literature review to highlight all the parameters involved in sub-prosthetic radicular fractures of teeth supported by metallic dental core. Materials and Methods: The following research was performed among published studies over the last 10 years in two PubMed/Medline and Scopus and supplemented by manual searching within the bibliographies. The search was restricted to publications in English and French. Results: Out of the 1464 articles initially identified, 18 studies met our inclusion criteria and were subsequently included in the literature review. These consisted of eight Finite Element Analysis Studies, two Retrospective Studies and one Randomized Controlled Trial. The results of this review show that radicular fractures are influenced by several variables, including predisposition, with maxillary premolars and mandibular molars being the most commonly affected teeth. Intracanal preparation can induce crack formation, leading to localized high stress concentrations. Increased ferrule height to 2 mm significantly enhances dental fracture resistance. Using high modulus of elasticity alloys results in nearly complete stress transmission to dentin due to their limited deformability and absorption capacity. The highest fracture resistance is achieved when posts are sealed using resin-modified glass-ionomer cement. Longer posts may be preferable to prevent vertical fractures. Additionally, occlusal factors, through repetitive stresses, contribute to crack propagation from surface defects, a phenomenon termed fatigue fracture. Conclusion: These findings have significant implications. Practitioners should be aware of the predisposition of certain teeth, the importance of preserving the ferrule effect, the choice of root post materials, post Cement Material and the role of occlusal forces in managing and preventing vertical root fractures.

Stresses in Premolars Restored Using Different Post-and-Core and Crown Materials: An FEA Study.

PURPOSE: The aim of the present study was to investigate the influence of three post-and-core systems and two crown materials on stresses in restored premolars using Finite Element Analysis (FEA). MATERIALS AND METHODS: A maxillary second premolar 3D model was created in SolidWorks 2014 (Dassault Systémés). Severe loss of tooth structure was simulated with six restorative options: 1) glass-fiber-reinforced composite post and composite core (GFRC)+CAD/CAM leucite-reinforced glass-ceramic crown (LRC); 2) carbon-fiberreinforced composite post and composite core (CFRC)+LRC; 3) metal cast post-and-core (MPC)+LRC 4) GFRC+CAD/CAM composite resin crown (CC); 5) CFRC+CC; 6) MPC+CC. Three-point occlusal loading (150N) was simulated and von Misses and maximum principal stresses calculated. RESULTS: Although maximum von Mises stresses in the crown and dentin were similar across groups (137.9-139.2MPa crown; 17.2-19.6 dentin), there were important differences in stress distribution in dentin. Only in MPC+CC group the maximum stresses were on the bottom of the post preparation cavity. Stress values within the posts were: CFRC(4.8MPa)>GFRC(6.7MPa)>MPC(10.3MPa). CC-restored models presented higher von Mises stresses within the post-and-core compared to the LRC groups. Maximum principal stresses were lower compared to von Mises stresses, following the same trend, and were distributed similarly in all the groups. CONCLUSIONS: Both GFRC and CFRC showed favourable stresses distribution in the dentin and restorative materials, while MPC increased stresses in core, post and post cement. The more rigid crown material seems to transmit less stresses to the underlying core and crown cement compared to CC.

The effect of ultrasonic vibration protocols for cast post removal on the incidence of root dentin defects.

PURPOSE: To investigate the effects of two ultrasonic vibration protocols for cast post removal (single or double ultrasound units) on the development of defects in root dentin. METHODS: Sixty bovine incisors were selected. Fifteen roots were left unprepared (control). Forty-five roots were instrumented and filled. A 10-mm post space was prepared using #1-4 Largo drills. Fifteen teeth were prepared for post space and received no further procedure. Thirty roots had cast posts cemented and were submitted to ultrasonic vibration protocols for removal. The time necessary to remove each post was recorded. Roots were sectioned 3, 6, 9, and 12 mm from the coronal portion and viewed through a 25× magnification in a stereomicroscope. The presence of root fractures, partial cracks, and craze lines was registered. Chi-square and Fisher's exact tests were performed to compare the incidence of dentin defects. The Kruskal-Wallis test was performed to explore the difference between the time needed for post removal. The significance level was set at P = 0.05. RESULTS: Root defects were observed in all experimental groups. There were no statistical differences comparing previous root canal treatment and post removal steps, either with 1 or 2 ultrasonic units, in the formation of defects (P = 0.544) or fractures (P = 0.679). CONCLUSION: Ultrasonic vibration protocols for removing cast posts did not increase the number of dentin defects compared to root canal preparation and obturation and post space preparation steps.

Understanding the Complexities of Cast Post Retention: A Comprehensive Review of Influential Factors.

This comprehensive review delves into the intricate landscape of cast post retention in restorative dentistry, encompassing historical perspectives, contemporary techniques, and future directions. Examining factors ranging from tooth-related considerations to prosthesis-related dynamics, the review provides a detailed analysis of clinical techniques, including step-by-step procedures, common challenges, and innovative advancements. Technological breakthroughs, such as digital impressions, computer-aided design and computer-aided manufacturing (CAD/CAM) technology, three-dimensional (3D) printing, and finite element analysis, are explored for their transformative impact on precision and customization. The discussion extends to the promising future of cast post retention, emphasising emerging materials, the integration of artificial intelligence in treatment planning, and patient-specific approaches. Implications for clinical practice underscore the importance of individualised treatment planning and the adoption of advanced technologies. Recommendations for future research advocate for comprehensive long-term clinical studies, investigations into AI-driven treatment planning, and a focus on patient outcomes and satisfaction. This review consolidates existing knowledge and anticipates a future marked by enhanced precision, individualised care, and improved long-term success in cast post-retained restorations.

Radiographic Analysis of Posts Performed by Undergraduate Dental Students: A Cross-Sectional Study.

INTRODUCTION: Post and core restorations for endodontically treated teeth must meet certain prosthetic criteria to ensure the success of the final restoration. The aim of this study is to evaluate the quality of posts performed by dental students at King Abdulaziz University Dental Hospital (KAUDH), Jeddah, Saudi Arabia, utilizing periapical radiographs and whether the prosthetic criteria were strictly met by students. MATERIALS AND METHODS: This cross-sectional study included 661 digital periapical radiographs of posts performed by 6th-year dental students from September 2018 to April 2019. The assessment included the following factors: patient's age, patient's gender, tooth type, and arch. Post-related factors including post type, shape, diameter, length, and status of the remaining gutta percha were also evaluated. Statistical analysis was performed using SPSS. Descriptive statistics were generated, and the association between different variables was determined using chi-square test at p<0.05. RESULTS: Posts were used to restore maxillary teeth (67%), and were particularly placed in premolars (44%). The majority of used posts were prefabricated tapered fiber posts (90%). The results were as follows: post diameter equal to one-third of root diameter, 50% met criterion; post length equal to two-thirds of root length, 33%; post length equal to or more than crown height, 93%; absence of space between gutta percha (GP) and post, 74%; and length of the remaining GP equal to 3-5 mm, 68%. Overall, 11% of the posts met all the ideal prosthetics criteria. CONCLUSION: Most qualities of post and core restorations that were radiographically assessed were found to be acceptable and within the recommended prosthodontic criteria.

Antimicrobial study of cast post and its surface modification with nanoparticle.

A cast post is a one-piece unit that is custom fabricated for the tooth at the dental laboratory. Traditional extracts such as neem and green tea have good antimicrobial and antioxidant activity against pathogens. The empty canal space may provide a suitable environment for promoting bacterial growth. The main aim of the study is to find the antimicrobial activity of the cast post coated with the nanoparticle. Prepared cast post was coated with prepared green tea and neem-mediated zinc oxide (ZnO) nanoparticles. Culture is done in agar media where control is noncoated post and another is nanoparticle coated post was implanted in the agar media. The zone of inhibition was noted and statistical analysis was done. The maximum zone of inhibition found on Candida albicans (19.333 2.081) followed by Enterococcus faecalis (14.000 3.605), and Streptococcus mutans (12.666 2.516). Green tea and neem-mediated ZnO nanoparticle showed good antimicrobial activity against the tester microorganism. Cast post coated with nanoparticles has been proved to be important as it is helpful in the prevention of origin and spread of infection around the canal and through the apical foramen.

Application of polymeric porcelain color-masking cast posts in the aesthetic repair of anterior teeth: a case report.

Many patients with large-area tooth defect need cast post-core crown restoration. However, the color defect of the cast post-core will affect the final restorative result, especially that of the anterior teeth. A new technology of color masking by applying CERAMAGE polymeric porcelain to the cast metal post-core surface improves the color of a full-ceramic restoration of anterior teeth and may provide a new alternative for the aesthetic repair of anterior teeth with a large area of defective tooth.

Evaluation of accuracy of fit in cast metal post fabricated with direct and indirect techniques using micro-CT - An in vitro study.

CONTEXT: Accuracy of fit of cast metal posts fabricated with direct and indirect techniques. AIMS: To evaluate the accuracy of fit of cast metal posts fabricated with direct and indirect techniques using micro-CT. MATERIALS AND METHODS: Sixty extracted human maxillary central incisors were used. The teeth were decoronated leaving 2 mm at the cementoenamel junction. Four patterns for each tooth were made including one direct and indirect wax pattern and one direct and indirect resin pattern. In total, 240 patterns and castings were made. Each tooth was scanned using microcomputed tomography (µCT) system with a resolution of 14.5 µm. µCT analyzer Sky scanner software was used to calculate the volume of space between the post and the canals. Statistical analysis used: The student paired t-test and unpaired t-test were used to determine the significant differences between groups. RESULTS: The overall space between the canal walls and posts made with the direct wax and resin technique had an average mean value of 1.10 mm3, whereas with the indirect technique resin and wax pattern, the average mean was 1.30 mm3 which was significant. CONCLUSION: Within the limitations of the study, it was found that the accuracy of fit is better in direct technique using wax pattern.

Application of polymeric porcelain color-masking cast posts in the aesthetic repair of anterior teeth: a case report / 华西口腔医学杂志

Many patients with large-area tooth defect need cast post-core crown restoration. However, the color defect of the cast post-core will affect the final restorative result, especially that of the anterior teeth. A new technology of color masking by applying CERAMAGE polymeric porcelain to the cast metal post-core surface improves the color of a full-ceramic restoration of anterior teeth and may provide a new alternative for the aesthetic repair of anterior teeth with a large area of defective tooth.

Comparative Study on Fracture Resistance of Endodontically Treated Tooth in Relation to Variable Ferrule Heights Using Custom-made and Prefabricated Post and Core: An In Vitro Study.

INTRODUCTION: Endodontically treated teeth have significantly differentphysical properties compared to vital teeth. To ensure functional longevity,endodontically treated teeth must have at least 5 mm of tooth structure coronalto the crestal bone, 2 mm of coronal tooth structure incisal to the preparationfinish line are necessary to ensure functional integrity. AIM AND OBJECTIVES: To evaluate fracture resistance of endodontically treated teeth restored withcustom cast post, custom cast post with variable ferrule height and teethwithout ferrule, prefabricated post with variable ferrule height and teethwithout ferrule. To compare fracture resistance of teeth restored with customcast post and prefabricated post with variable ferrule heights. MATERIALS AND METHODS: Methodology includes selection of teeth, root canal preparation,post space preparation, grouping of samples, Group A-custom cast post andcore with sub groups of variable ferrule height, pattern fabrication, Group A- pattern fabrication for customized cast post. Group B-pattern fabricationfor prefabricated post and core, investing and casting, cementation, custommade acrylic jig preparation, testing of specimens. RESULTS: The differencein the fracture load between the samples of Group A was highly significantat the 0.001 level. Subgroup A4 had highest fracture resistance while GroupA, possessed the least fracture resistance. Subgroups A2, A3 had fractureresistance value intermediate between A1, A4. CONCLUSION: Increasing theferrule height significantly increases (P < 0.001) the fracture resistance ofendodontically treated teeth restored with both custom made cast post andcore and prefabricated post with metal core. Comparatively the custom madecast post and core with variable ferrule height, especially 2 mm ferrule showedsignificant fracture resistance than prefabricated post with metal core. Thepresence of 2 mm ferrule height significantly increases (P < 0.001).

To evaluate the fracture resistance of proclined endodontically treated teeth with different post and core systems: In vitro study.

AIM: This study was aimed to evaluate the fracture resistance of proclined endodontically treated teeth with different post and core systems. SETTINGS AND DESIGN: Experimental in vitro study. METHODOLOGY: Eighty extracted maxillary central incisors were selected and decoronated keeping 2 mm of crown ferrule and were endodontically treated. Postspace was prepared retaining 5 mm apical gp using peeso 3. Samples were divided into two groups. In Group 1, Wax pattern fabricated to accommodate different core angulations to be casted with Ni-Cr alloy. In Group 2, ever stick posts were angulated and cemented followed by porcelain fused to metal crown cementation for both the groups. Samples were thermocycled and subjected to the universal testing machine. STATISTICAL ANALYSIS USED: One-way ANOVA and Tukey's post hoc test were used to compare the mean fracture resistance between different angulations in cast post and ever stick posts. Student's paired t-test was used to compare the mean fracture resistance between cast post and everstick posts for each angulations. P value was set at P < 0.05. RESULTS: The fracture resistance was the highest at 20° and lowest at 30° core angulations in both the groups. CONCLUSIONS: Changing core angulation up to 20° can be carried out safely using any of the post systems tested in the study. Core angulations >20°, should be used with caution, especially in patients with abnormal parafunctional habits and occlusal trauma.

Evaluating Fracture Resistance And Failure Modes Of Root Filled Teeth Restored With CAD/CAM-Fabricated Post And Core.

OBJECTIVE: The aim of this study was to measure the fracture resistance and failure modes of root-filled teeth restored with three different computer-aided design/computer-aided manufacturing (CAD/CAM)-fabricated post and core assemblies. METHODS: Thirty extracted intact maxillary central incisors were used in the study, and the teeth were endodontically treated and sectioned to a root length of 16 mm. The samples were divided into three groups (n = 10) according to the mean of the dimensions at the cervical portion of the root. The posts and cores were fabricated with CAD/CAM technology using metal, zirconia, and polymer-infiltrated ceramic network (PICN) material. The posts were luted using resin cement, and then, metal crowns were fabricated, cemented, and then subjected to a compression to determine the fracture resistance force. Fracture of the post and core or fracture of the root above the level of the acrylic resin was considered as a favorable fracture, while nonfavorable fractures were those where the root fracture occurred below the level of the acrylic resin. Statistical analysis was carried out using SPSS software, and one-way analysis of variance was used to analyze root fracture resistance in Newton. The number of failure modes, post-core fractures and/or root fractures was calculated. The differences between study groups were revealed using the chi-square test. RESULTS: The results of ANOVA revealed a nonsignificant difference in the resistance to fracture among the study groups (P = 0.114). The failure modes were nonfavorable for all metal and zirconia samples and seven PICN samples. However, three PICN samples exhibited a favorable represented by core fracture without root fracture. CONCLUSION: There was no significant difference between metal and zirconia samples in terms of nonfavorable fracture, while few PICN samples exhibited a favorable fracture. PICN material can be used in the fabrication of post and core assemblies using CAD/CAM.

Dentists' perspectives on the reconstruction possibilities of a non-vital tooth.

BACKGROUND AND AIMS: The decision-making process when restoring a non-vital tooth is influenced by multiple factors. This study aimed to survey the dentists' preferences regarding cast post-and-core and fiber post techniques for the reconstruction of non-vital teeth and to identify a correlation between reconstruction technique and practitioners characteristics, or dental characteristics. METHODS: The survey instrument was a questionnaire, which included a general part with questions regarding the practitioner's profile (gender, age, years of experience, pattern and location of practice, etc.) and the dental characteristics (anterior or posterior position of the tooth on the arch, the amount of dental remaining tissues, etc.) and a technical part, containing more specific questions regarding the manufacture and performance of root-coronal reconstructions. RESULTS: Among the surveyed practitioners (n=35), 69.7% use more often cast post-and-core reconstructions (CPR) while 30.3% choose fiber post reconstructions (FPR). No difference in the reconstruction type was observed regarding patient's age (p=0.23) or gender (p=0.092). The para-function criterion was considered important by 8.23% of the participants. When deciding the type of the root-coronal reconstruction depending on the remaining dentine walls, CPRs are significantly more frequently used in posterior areas (p=0.043) or when para-functional habits exist (p=0.022). CONCLUSION: Cast post-and-core represent the most frequently used type of reconstruction for non-vital teeth. Fiber post reconstructions are indicated in the aesthetic zone and when the amount of healthy remaining dental structure is higher.

An In Vitro Evaluation of Fracture Resistance of Endodontically Treated Maxillary Central Incisor Restored with Custom-Made Cast Post and Core with Uniform and Nonuniform Core Ferrule Heights.

AIM: The aim of this study was to evaluate in vitro fracture resistance of endodontically treated teeth restored with custom-made cast post and core having uniform and nonuniform core ferrule heights. MATERIALS AND METHODS: Thirty-five freshly extracted human maxillary central incisors were included in this study. All teeth were subjected to standard root canal treatment. The teeth were randomly divided into five groups-Group 1: uniform ferrule (2 mm buccal, lingual, and proximal), Group 2: uniform ferrule (3 mm buccal, lingual, and proximal), Group 3: nonuniform ferrule (2 mm buccal, 3 mm lingual), Group 4: nonuniform ferrule (2 mm buccal, 4 mm lingual), and Group 5: no ferrule. The teeth were sectioned horizontally 4 mm above cementoenamel junction and post space preparation was performed maintaining 4 mm of apical gutta-percha. Ferrule was prepared according to dimension designated for each group. Custom-made cast post and core were fabricated and luted using zinc phosphate cement. Testing was conducted using universal testing machine with application of static load (Newton), and failure load was recorded. Data were analyzed by one-way analysis of variance and Tukey test. The mode of fracture was noted by visual inspection for all specimens. RESULT: Significant differences (P < 0.001) were found among mean fracture forces of test groups. Group 1: 1181.66 ± 68.29, Group 2: 1455.58 ± 173.11, Group 3: 1019.00 ± 52.55, Group 4: 971.58 ± 66.52, and Group 5: 888.00 ± 60.56. The presence of nonuniform ferrule height resulted in a significant decrease (P < 0.0001) in mean fracture strength compared to uniform 2- and 3-mm core ferrule height. CONCLUSION: The central incisors restored with cast post and core and crowns with 3-mm uniform core ferrule were more fracture resistant compared to central incisors with nonuniform core ferrule height. Both the uniform and nonuniform core ferrule groups were more fracture resistant than the group that lacked ferrule.

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

PURPOSE: 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. MATERIALS AND METHODS: 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 7 mm 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 7 days. Then, the teeth were subjected to thermocycling, immersed in silver nitrate for 6 hours, 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. RESULTS: The median microleakage in ZP, Speed CEM, GI, and Panavia were 171.89, 114.76, 26.51, and 20.02 µm, 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). CONCLUSION: 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.

Masking a Metal Cast Post and Core Using High Opacity e.max Ceramic Coping: A Case Report.

RATIONALE: Advancements in dental biomaterials have led to the introduction and application of ceramic-based restorations in dental practice. Currently, ceramic restorations are used in crowns and fixed partial dentures. The optical properties of ceramic restorations are comparable to natural teeth in terms of light scattering and transmission. However, the translucency of ceramic restorations could be a limitation if cemented over metal posts or severely discolored dentin. Therefore, accomplishing the maximum esthetic outcome mandates adequate management of severely discolored foundation. PATIENT CONCERNS: The patient wanted to improve the esthetic of his anterior teeth. DIAGNOSIS: This case report describes a clinical case in which the patient had defective restoration in his upper anterior teeth and base-metal cast post and core in his left lateral incisor (tooth #22). INTERVENTIONS: Metal-free full crowns were used in the anterior zone of the maxilla with the help of e.max HO (high opacity) coping to mask the dark core buildup of the base-metal post and core on tooth #22. OUTCOMES: The color of the substrate was masked completely. The esthetic of the anterior teeth was improved and the patient was highly satisfied with the outcome. LESSONS: e.max HO coping offers clinically acceptable masking ability.

A novel and easy technique for restoring grossly decayed mandibular molar with a modified cast-post.

The article addresses the difficulty of restoring a grossly carious molar tooth, where very little tooth structure is left after caries excavation. When enough sound tooth structure is missing for satisfying the ferrule effect, a clinician can follow this technique and easily restore such teeth. A step by step procedure, including instrumentation and materials and a new impression technique, is described in detail, with clinical photographs. This technique results in the fabrication of a robust and extremely retentive post and core on which to place fixed prosthodontic restorations. A 2 and half year study showed that the tooth well in function with no signs of any problem. The author has restored around many decayed molars using this technique. Over a period of three years, no failure was reported. With an increasing demand on the dentist for restoring a structurally compromised teeth, this technique provides the patients with a robust prosthodontic solution.

Fracture resistance of upper central incisors restored with different posts and cores.

OBJECTIVES: To determine and compare the fracture resistance of endodontically treated maxillary central incisors restored with different posts and cores. MATERIALS AND METHODS: Forty-eight upper central incisors were randomly divided into four groups: cast post and core (group 1), fiber-reinforced composite (FRC) post and composite core (group 2), composite post and core (group 3), and controls (group 4). Mesio-distal and bucco-lingual dimensions at 7 and 14 mm from the apex were compared to ensure standardization among the groups. Twelve teeth were prepared for crown restoration (group 4). Teeth in other groups were endodontically treated, decoronated at 14 mm from the apex, and prepared for posts and cores. Resin-based materials were used for cementation in groups 1 and 2. In group 3, composite was used directly to fill the post space and for core build-up. All samples were restored by standard metal crowns using glass ionomer cement, mounted at 135° vertical angle, subjected to thermomechanical aging, and then fractured using a universal testing machine. Kruskal-Wallis and Mann-Whitney U tests were used to analyze the data. RESULTS: Fracture resistance of the groups was as follows: Control (group 4) > cast post and core (group 1) > fiber post and composite core (group 2) > composite post and core (group 3). All samples in groups 2 and 3 fractured in restorable patterns, whereas most (58%) in group 1 were non-restorable. CONCLUSIONS: Within the limitations of this study, FRC posts showed acceptable fracture resistance with favorable fracture patterns for reconstruction of upper central incisors.