Showing papers on "Post and core published in 2023"

Fatigue survival of endodontically treated teeth restored with different fiber-reinforced composite resin post strategies versus universal 2-piece fiber post system: An in vitro study

Abstract: Various strategies have been proposed to reduce the cement space of foundation restorations for endodontically treated teeth. However, they may add more operative steps, or the dentist must keep different sizes of drills and posts in stock. A 2-piece universal adjustable post system has been developed to overcome this problem, but whether the system has acceptable fatigue survival performance is unclear.The purpose of this in vitro study was to evaluate the fatigue survival and stress distribution of endodontically treated teeth without a ferrule and restored with different glass fiber post strategies versus a recently introduced universal 2-piece fiber post system.Bovine incisor roots were randomly assigned to 3 groups as per the post used (n=13): adapted glass fiber post with post space preparation of the same size, composite resin-custom glass fiber post (CTM), and universal 2-piece glass fiber-reinforced composite resin post (UNI). The posts were adhesively luted, the composite resin core was added, and a composite resin crown was produced with computer-aided design and computer-aided manufacturing (CAD-CAM), and then adhesively luted to each core. A fatigue test was performed with the stepwise stress method (10 000 cycles/step; 20 Hz; load=100 N to 750 N; step=50 N) until fracture, and the failure mode analyzed. The stress distribution was evaluated by finite element analysis with the maximum principal stress criteria by following the parameters of the in vitro test. The solids were considered homogeneous, linear, and isotropic, except for the glass fiber post (orthotropic), and a load of 450 N at 30 degrees was applied. The fatigue failure load and the number of cycles for failure were analyzed with Kaplan-Meier and Mantel-Cox (log rank test) (α=.05). The finite element analysis results were analyzed with colorimetric graphs.The highest fatigue failure load and the number of cycles for failure were found in the UNI system, whereas the lowest results were found in the CTM group. All groups exhibited repairable failures. The finite element analysis showed the lowest stress in root dentin in the UNI system. The CTM system had the largest stress regions at the dentin and dentin-core interface.The use of a 2-piece universal glass fiber post system resulted in more fatigue behavior compared with composite resin-custom glass fiber posts.

Finite Element Analysis of the Mechanical Performance of Non-Restorable Crownless Primary Molars Restored with Intracoronal Core-Supported Crowns: A Proposed Treatment Alternative to Extraction for Severe Early Childhood Caries

Abstract: Early childhood caries (ECC) involve extensive coronal tooth structure loss, and tooth reconstruction remains highly challenging. To fulfill preclinical assessment, the present study investigated the biomechanics of non-restorable crownless primary molars that were restored by stainless steel crowns (SSC) using different composite core build-up materials. Computer-aided design-integrated 3D finite element and modified Goodman fatigue analyses were performed to determine stress distribution, risk of failure, fatigue life and dentine–material interfacial strength for the restored crownless primary molars. A dual-cured resin composite (MultiCore Flow), a light-cured bulk-fill resin composite (Filtek Bulk Fill posterior), a resin-modified glass-ionomer cement (Fuji II LC) and a nano-filled resin-modified glass-ionomer cement (NRMGIC; Ketac N100) were used as core build-up composite materials in the simulated models. The finite element analysis showed that types of core build-up materials affected the maximum von Mises stress only in the core materials (p-value = 0.0339). NRMGIC demonstrated the lowest von Mises stresses and revealed the highest minimum safety factor. The weakest sites were along the central grooves regardless of type of material, and the ratio of shear bond strength to maximum shear stress at the core–dentine interface of the NRMGIC group was lowest among the tested composite cores. However, all groups provided lifetime longevity from the fatigue analysis. In conclusion, core build-up materials differentially influenced the von Mises stress (magnitude and distribution) and the safety factor in crownless primary molars restored with core-supported SSC. However, all materials and the remaining dentine of crownless primary molars provided lifetime longevity. The reconstruction by core-supported SSC, as an alternative to tooth extraction, may successfully restore non-restorable crownless primary molars without unfavorable failures throughout their lifespan. Further clinical studies are required to evaluate the clinical performance and suitability of this proposed method.

A comparative study to evaluate the fracture resistance efficiacy of three different luting agents used for adhesion of post in endodontically treated tooth

Abstract: Due to the carious processs peripheral destruction and the endodontic treatments central destruction, the majority of endodontically treated teeth are structurally compromised and weaker. In an effort to strengthen the tooth a post was placed to hold the core material in place when there was not enough clinical crown left. Thus the main Aim : of our study was to compare and evaluate the efficacy of three different luting cements to hold these core materials in place. Material And Methodology: 30 freshly extracted maxillary incisors were treated endodontically and decoronated 2mm above the cementoenamel junction and divided into three experimental groups based on the type of luting cements used. In group A glass ionomer cement, group B resin modified glass ionomer cement and in group C variolink II was used for cementation of pre fabricated post. Fracture resistance of the restoration was measured by applying loads at an angle of 135°. Results: fracture modes of all the samples were recorded and analyzed using mean and standard deviation. Inter and intragroup comparison was done using one way ANOVA test and Tukey HSD test. A statistically significant result was obtained between the three groups. Conclusion: An effective and significant observation was obtained when three groups were compared. Much higher results were obtained in group C where etched luting cement was used.

In Vitro Comparison of Fracture Resistance of Severely Damaged Primary Anterior Teeth Restored with Different Post and Core Systems

Abstract: Objectives This study aimed to compare the fracture resistance (FR) of severely damaged primary anterior teeth restored with five different post and core systems. Materials and Methods This in vitro, experimental study evaluated 60 extracted primary maxillary central incisors. The teeth were horizontally sectioned at 1 mm above their cementoenamel junction (CEJ), underwent pulpectomy, and their root canals were filled with Metapex paste. After post space preparation and sealing of root fillings with light-cure glass ionomer (1 mm thickness), the teeth were randomly assigned to five groups (n = 12) of (1) glass fiber post and everX composite (reinforced with short fibers), (2) glass fiber post and bulk-fill composite, (3) everX composite post and core, (4) bulk-fill composite post and core, and (5) Filtek conventional composite post and core. The teeth underwent 5,000 thermal cycles between 5°C and 55°C, and their FR was measured in a universal testing machine (0.5 mm/min, 148°). The mode of failure was also determined. Data were analyzed by ANOVA and Tukey's test at 0.05 level of significance. Results The FR was the highest in fiber post and everX composite, and the lowest in Z250 conventional composite post and core group (P < 0.001). The FR of fiber post and everX composite group was significantly higher than that of everX composite post and core (P = 0.04), bulk-fill composite post and core (P = 0.001), and Z250 composite post and core (P < 0.001) groups. The frequency of repairable fractures was the highest in glass fiber post plus everX composite (91.66%) and the lowest in Filtek conventional post and core group (66.66%) (P > 0.05). Conclusion Within the limitations of this in vitro study, the results showed that restoration of severely damaged primary maxillary central incisors with glass fiber post and everX composite reinforced with short fibers enhanced their FR, and increased the chance of reparability in case of restoration fracture. This technique may be recommended for the restoration of primary anterior teeth since it is simple and saves time.

An in vitro study to evaluate the fracture resistance of different types of posts

Abstract: Aim: The aim of this study was to evaluate the fracture resistance of endodontically treated maxillary central incisors restored with carbon fiber and glass fiber posts under static loading and evaluate their modes of failure. Materials and Methods: Sixty freshly extracted human maxillary central incisors were collected and root canal treatment was performed in all. Forty out of 60 teeth were sectioned 4 mm away from the cemento–enamel junction coronally and posts were placed in them. Rest 20 teeth were left intact to be used as controls. The groups were divided as follows: I—control group, II—carbon fiber group, and III— glass fiber group, All specimens were then mounted on an acrylic test block and subjected to static loading until fracture and the mode of fracture were recorded. Statistical analysis was carried out using analysis of variance (ANOVA) to calculate the mean values of all groups. An intergroup comparison was carried out using Tukey’s post hoc test. Results: The study showed that group I showed the highest fracture resistance followed by group III, which was the glass fiber post group under static loading. There was a significant difference among the test groups. The main cause of fracture was debonding of the core in all the fiber posts. Conclusion: Teeth of the control group showed the highest fracture resistance and teeth restored with glass fiber posts showed higher fracture resistance than those restored with carbon fiber posts under static loading (P < 0.05). The principal mode of fracture was debonding of the core and remaining root. Teeth restored without application of a post showed the highest fracture resistance than all other groups.

Synchronous Fabrication of Custom One-piece Glass Fiber Post-and-core and Zirconia Crown by a Fully Digital Workflow

Abstract: Combined crown and post-and-core treatment often requires multiple intermittent appointments and takes a long time. This article describes a novel method for simultaneously fabricating a custom glass fiber post-and-core and the corresponding crown. The critical step, defined as a post-and-core virtual try-in, is to construct a virtual crown abutment that mimics the profile of a real one gained after post-cementation and tooth preparation. The fully digital workflow optimizes the treatment and saves time by accomplishing restorations on the first visit.

Fracture resistance of endodontically treated maxillary premolars with Mesio-occluso-distal (MOD) cavities supported by horizontal glass fiber posts versus vertical glass fiber posts: An in vitro study

Abstract: Aim: The aim of this study was to assess the fracture resistance of endodontically treated maxillary premolars with mesioocclusodistal (MOD) cavities supported by horizontal glass fiber posts. Methodology: Thirty three extracted maxillary premolars were collected and grouped into three. MOD cavities were prepared and all of them were endodontically treated. Teeth were supported with horizontal glass fiber posts; vertical glass fiber posts and composite restoration alone in the three groups respectively. Fracture resistance assessed using Universal testing machine. Type of fracture was assessed using visual examination. Type of failure was assessed using Stereomicroscope. Results: Highest fracture resistance was shown by samples supported by horizontal fiber post (Group C). Group B had higher chances of Type 1 failure (Adhesive failure between post and luting cement) compared to other groups. Group A had higher chances of Type 4 failure (Cohesive failure) and Group C had higher chances of Type 5 failures (Mixed type; combination of any two of the above-mentioned types).There was no statistically significant association between groups and fracture mode (repairable and unrepairable). Majority of samples from Group A and Group C underwent repairable fractures. Conclusion: Fracture resistance of horizontal fiber post group was significantly higher compared to the other two groups.

In Vitro Evaluation of Lithium Disilicate Endocrowns and Post and Core Crowns—A Systematic Review

Abstract: The aim of this systematic review was to summarize the results of the studies that have compared the physical and mechanical properties of lithium disilicate (LDS) endocrowns constructed for posterior teeth to those retained by post-and-core retention systems. The review was conducted following the PRISMA guidelines. The electronic search process was conducted on PubMed-Medline, Scopus, Embase and ISI Web of Knowledge (WoS) from the earliest available date till 31 January 2023. Additionally, the studies were assessed for their overall quality and risk of bias using the Quality Assessment Tool For In Vitro Studies (the QUIN). The initial search resulted in 291 articles, out of which, only 10 studies met the eligibility criteria. In all studies LDS endocrowns were compared with various kinds of endodontic posts and crowns made from other materials. There were no definite pattern or trends observed in the fracture strengths of tested specimens. There was no predilection observed in failure patters among the experimental specimens. No predilection was observed in the fracture strengths of LDS endocrowns when compared to post-and-core crowns. Furthermore, no differences in failure patterns could be observed when both types of restorations were compared. The authors propose standardized testing of endocrowns against post-and-core crowns in future studies. In conclusion, long-term clinical trials are advocated to compare the survival, failure and complication rates of LDS endocrowns and post-and-core restorations.

Bond strength of various post-core restorations with different lengths and diameters following cycle loading.

Abstract: This in vitro study aims to evaluate the bonding strengths of Polyether ether ketone (PEEK), Polyether ketone (PEKK), Fiber, and Zirconia (ZrO2) post-core restorations with posts in different diameter and length following chewing simulator. Endodontic treatment was performed on 256 intact maxillary central teeth. The test specimens were prepared in four groups according to the types of materials: Glass fiber post-composite core (FB-n:64), Zirconia post-core (Zr-n:64), PEEK post-core (PE-n:64), and PEKK post-core (PK-n:64). The groups were divided into four subgroups according to diameter and length (n:16): Group 1: 10 mm length 1.75 mm diameter, Group 2: 10 mm length 1.5 mm diameter, Group 3: 7 mm length 1.75 mm diameter, Group 4: 7 mm length 1.5 mm diameter. Custom PEKK, PEEK, Zirconia post-cores, and Zirconia crowns were milled on the CAD/CAM. The post-cores and crowns were cemented to the teeth with dual-cure resin cement. After that, all subgroups were divided into control and cyclic loading groups. During the cycling, the control test group was kept in distilled water at 37±1oC before the push-out test. Half of the specimens were loaded with 250,000 cycles and 50 N with a chewing simulator. All test specimens had 1.5 mm sections taken from their roots. Then, the push-out test was applied to these sections for bond strength. Data were analyzed by Mann-Whitney U test, Shapiro-Wilk, Kruskal-Wallis's test, and Chi-Square. The statistical significance level was determined as 0.05. The bond strength of all test groups decreased after the cycling loading. The bond strength values of zirconia posts showed a statistically significant difference (p < 0.05). The 10 mm length 1.75 mm diameter posts made of Zirconium had the highest bond strength observed in all control and cyclic loading groups of test specimens (9.74 MPa-6.25 MPa). The PEEK test specimens with a 7 mm length and 1.75 mm diameter showed the weakest bond strength in all control and cyclic loading groups (5.44 MPa-3.37 MPa). The average of the cervical region's bond strength values was statistically significantly higher than the apical region (p < 0.05). Within the limitations of this study, one-piece custom-milled Zirconia post-cores appear promising, as they perform well under functional forces, especially in the anterior region. In addition, custom-milled PEKK post-cores might be considered a suitable alternative to prefabricated fiber-reinforced posts.

Non-ferrule design for indirect restoration of endodontically treated premolars with severe hard tissue loss

Abstract: Abstract Objectives This study aimed to predict the potential of endocrown and non-retentive crown restoration designs without post-and-core build-up made of either lithium-disilicate (Li) or CAD-CAM composite resin (CR). Materials and Methods After removing the clinical crown sixty endodontically treated human maxillary premolars were restored accordingly to group C = glassfibre-reinforced post and composite core-build-up with ferrule design and crown restoration (control); group NRC = non-retentive crown preparation without endodontic post and no-ferrule design and group EC = endocrown design with internal extension. Prior to linear loading until failure (Fmax) all crown restorations were subjected to thermal cycling and simultaneous mechanical loading (TCML). The maximum load capabilities (Fmax) were compared using Kruskal-Wallis and Mann-Whitney analyses. The marginal gap formation was evaluated before and after TCML. Results All specimens survived the TCML. Specimens of group C/CR (502.5 N) and NRC/CR (481.5 N) revealed significant lower load capabilities (p < 0.03). The endocrowns (EC/CR 725 N; EC/Li 637 N) show high and no significantly different Fmax values compared to groups C/Li (665 N) and NRC/Li (726.5 N). The marginal gap analyses reveals a higher percentage of restoration margin alteration for CR. Conclusions Regarding the load capability of endodontically treated premolars, endocrowns and non-retentive crowns made from Li and endocrowns made from CR show comparable load capabilties to post-and-core crown restorations. Clinical Relevance: Single crown restorations for endodontically treated premolares with non-retentive crown design without post-and-core build-up and endocrowns are promising treatment alternatives to preserve a maximum of tooth hard tissue.

Ferrule Effect on Fracture Resistance of Endodontically Treated Teeth Restored With Two Esthetic Post and Core Materials Fabricated With Different Techniques

Abstract: : Objective: Assessment of ferrule effect on fracture resistance of Customized fiber post and Custom-made PEEK post with a core. Materials and Methods: Twenty eight single-rooted mandibular premolars with approximate similarity in shape and size and no cracks or caries were selected for this study. The length of the root was measured from the root apex to the middle point of the cementoenamel junction in the labial surface; it was about (16±1 mm). Teeth were divided into two groups, each group contained 14 teeth, with a ferrule group and without a ferrule group followed by coronal decapitation of all samples. Endodontic treatment was performed for all samples followed by mounting samples in acrylic blocks and then preparation of post space. Each group of the two groups was subdivided into two subgroups (n=7/subgroup), the first subgroup was restored with custom-made polyether ether ketone (PEEK) post and core, and the second subgroup was restored with customized fiber post and composite resin core. Results: Samples with ferrule (651.68±66.34) had a significantly higher fracture strength value than samples without ferrule (528.86±60.85) (p<0.001). Conclusions: based on the results and conditions of this study, the following findings can be drawn: With ferrule samples are more resistant to fracture than ferrule samples with the two different post types.

Effect of the Gap between Cemented Posts and Remaining Gutta-Percha on the Clinical Outcome of Endodontically Treated Teeth Managed by Undergraduate Dental Students: A Prospective Study with 4 Years of Follow-Up

Abstract: It is common to detect a gap between the apical portion of the post and the most coronal part of gutta-percha in a root canal during post and core treatment in endodontically treated teeth. It may compromise the seal that gutta-percha material provides in the root canal filling, leading to apical leakage, which is often thought to be one of the most common causes for failure of endodontic treatment. The prevention of apical leakage to achieve a complete apical seal and its effect on periapical health of endodontically treated teeth of post and core in long term clinical research remains unanswered. Post and core treatment were provided to 100 patients by undergraduate students in the year 2016–2017. A total of 70 patients in all were called back to the Prosthodontic Clinic for follow-up care after 4 years to assess the clinical result in terms of the gap between the post-operative and residual gutta-percha. The cemented posts were divided into three groups depending on the space between the cemented post end and the remaining gutta-percha: group I revealed no gaps, group II revealed gaps between >0.1 and 1 mm, and group III revealed gaps more than 1 mm. The periapical index (PAI) was used to determine the apical condition of each tooth. Chi-square test was used for evaluating the data, and a p-value of 0.05 was considered statistically significant. A total of 28.6% post and core treated teeth were found diseased while 71.4% teeth were found normal. In group I, 90% of the teeth and in group II, 66.7% of teeth were evaluated as normal; however, in group III, 41.2% teeth were found diseased. In endodontically treated teeth restored with a post and core, a gap between the apical end of the post and the coronal section of the residual gutta-percha was associated with a greater prevalence of disease. The post and core treatment by undergraduate students achieved a clinically acceptable outcome in terms of the gap between the post end and the remaining gutta-percha.

Dental Fiber-Post Systems: An In-Depth Review of Their Evolution, Current Practice and Future Directions

Abstract: The field of dental medicine is constantly evolving and advancing toward minimally invasive techniques. Several studies have demonstrated that bonding to the tooth structure, particularly enamel, yields the most predictable results. In some instances, however, significant tooth loss, pulpal necrosis, or irreversible pulpitis may limit the options available to the restorative dentist. In these cases, placement of a post and core followed by a crown is the preferred treatment option, provided all requirements are met. This literature review provides an overview of the historical development of dental FRC post systems as well as a comprehensive examination of the currently available posts and their bonding requirements. In addition, it offers valuable insights for dental professionals seeking to understand the current state of the field and the prospects of dental FRC post systems.

General consideration of post systems

Abstract: More often than not pulpless teeth remain relatively intact after conservative endodontic treatment. Although it hasn't been shown that endodontically treated teeth are more brittle than healthy ones, pulpless teeth are known to crack during mastication. As a result of this known phenomenon, dental professionals have been looking for strategies to prevent pulpless teeth from breaking. Restoration and reinforcement of pulpless teeth is a crucial preventative step in endodontic therapy. A post is cemented into the root canal to reinforce a healthy endodontically treated tooth. The post is supposed to reinforce the tooth and keep it from breaking. A widely used technique for repairing teeth that have undergone endodontic treatment is post and cores. Retention applied onto the root thorough final restoration using the post and core restoration as a substructure. Therefore, post placement in the root is crucial. In order to ensure retention for a fixed restoration, endodontically treated teeth are frequently treated with posts and cores. Teeth that had gone through endodontic treatment often suffer from severe coronal damage. In order to ensure retention for full or partial coverage restoration, these teeth may require a coronal substructure or core for retention of a full or partial bonding restoration. Generally, primary retention feature of a core is an intraradicular post. Posts and cores are routinely used for endodontical teeth restoration. This article provides a review presentation about utilization of post systems on the pulpless tooth.

The infection control of post-and-core crown restoration.

Abstract: Post-and-core crown is one of the most common forms of restoration of tooth after root canal therapy (RCT). Infection control is the core objective of RCT, which is usually well realized by endodontists. However, many prosthodontists often neglect the infection control of the tooth and the maintenance of the curative effect of RCT during the process of post-and-core crown, which may lead to the failure of the final restoration. The concept of integrated crown-root treatment advocated recently requires clinicians to consider the RCT and final restoration as a whole, rather than simply divided into two parts-endodontic treatment and restorative treatment. As the core content of integrated crown-root treatment, infection control should be taken seriously by clinicians and implemented throughout the whole treatment process, especially in the restorative treatment that is easily overlooked after RCT. Therefore, this article describes the infection control of post-and-core crown restoration, classifies the tooth requiring post-and-core crown restoration, and puts forward the measures of infection control before and during post-and-core crown restoration, in order to provide reference and guidance for clinical practice.

Application of polyetheretherketone (PEEK) posts: evaluation of fracture resistance and stress distribution in the root: in vitro and finite element analyses.

Abstract: To evaluate the feasibility of using a milled polyetheretherketone (PEEK) post and core in endodontically treated teeth with or without a ferrule. Sixty bovine tooth roots were endodontically treated followed by cementation of intraradicular retainers (IR), according to each experimental group: a) non-ferrule glass fiber post (f0FP); b) 2-mm-ferrule glass fiber post (f2FP); c) non-ferrule resized glass fiber post (f0PR); d) 2-mm-ferrule resized glass fiber post (f2PR); e) non-ferrule PEEK post and core (f0PPC); and f) 2-mm-ferrule PEEK post and core (f2PPC). Metal crowns were made and cemented. A periodontal ligament was simulated using polyether. A force was applied to the palatine portion of each sample at 45°, until fracture. Fracture resistance data were submitted to two-way ANOVA and Tukey's test (α = 0.05). Three-dimensional digital models were developed to calculate the tensions formed in the root using finite element analysis. Models of glass fiber posts and PEEK posts and cores were evaluated with or without a ferrule. The results were analyzed by the Mohr-Coulomb criterion. The type of IR was not influenced by fracture strength (p = 0.243). There were significant statistical differences among the remaining factors. Ferrule groups had greater fracture resistance, and the failure mode of teeth with a ferrule was more catastrophic than the non-ferrule group. A ferrule increases fracture resistance and influences failure mode; the PEEK post and core did not modify the biomechanics of endodontically treated teeth, and resembled the glass fiber post results. The crack initiation point differed between the ferrule and non-ferrule groups.

Rehabilitation of Fractured Maxillary Anterior Teeth Using Custom Cast Post and Core: A Case Series

Abstract: Crown fractures of permanent anterior teeth due to trauma is the most frequent type of injury encountered. Anterior crown fractures lead to discomfort and serious psychological esthetic functional effects on the patients. Endodontic management of such teeth may require a post and core to reinforce the coronal restorations. A wide range of post systems are available today. Custom cast post and core has been the standard for many years. This case series explains about the management of mutilated anterior teeth by means of custom cast post and core followed by full coverage crowns.nbsp

A composite resin core with a new zirconia tube reduces the surface strain at the cervical area of a mandibular molar: A model tooth study

Abstract: Purpose: This study aimed to evaluate the surface strain at the cervical area of endodontically treated molars with a large pulp chamber restored using a composite resin core with three different types of core build-up systems.

A Comparative Evaluation of Micro-Leakage in Fiber Post Luted and Core Buildup Performed with Two Different Resin Cements

Abstract: Objective: To compare the micro-leakages of fiber post luted and core buildup performed with ParaCore (Coltene) and LuxaCore (DMG) resin cement. Materials and Methods: Thirty-six single-rooted teeth were selected and treated with root canal treatment and fiber post cementation with two types of resin cement (LuxaCore and ParaCore). Samples were exposed to 500 cycles of thermocycling, immersed in 2% methylene dye and centrifuged and sectioned longitudinally, and checked under a stereomicroscope. Results: LuxaCore and ParaCore showed a mean of 0.39250 mm and 0.47500 mm micro-leakage, respectively. Conclusion: There was a statistically non-significant difference seen with group 3 (LuxaCore) versus group 4 (ParaCore) (P > 0.05).

The effect of different ferrule heights and crown-to-root ratios on fracture resistance of endodontically-treated mandibular premolars restored with different post-and-core systems: an in vitro study

Abstract: Abstract Background To investigate the effects of different ferrule heights and crown-to-root ratios on the fracture resistance of endodontically-treated premolars restored with two post-and-core systems. Methods Eighty extracted human mandibular first premolars with single root canal were treated endodontically and cut from 2.0 mm above the buccal cemento-enamel junction, to create horizontal residual roots. The roots were randomly divided into two groups. The roots in group FP were restored with a fiber post-and-core system, while the roots in group MP were restored with a cast metal post-and-core system. Each group was divided into five subgroups with different ferrule heights (0: no ferrule; 1: 1.0mm ferrule; 2: 2.0mm ferrule; 3: 3.0mm ferrule; 4: 4.0mm ferrule). All specimens were subsequently restored with metal crowns and embedded in acrylic resin blocks. The crown-to-root ratios of the specimens were controlled at approximately 0.6, 0.8, 0.9, 1.1, and 1.3 of the five subgroups, respectively. Fracture strengths and fracture modes of the specimens were tested and recorded by a universal mechanical machine. Results Mean fracture strengths (mean ± standard deviation (kN)) of FP/0 to FP/4 and MP/0 to MP/4 were: 0.54 ± 0.09, 1.03 ± 0.11, 1.06 ± 0.17, 0.85 ± 0.11; 0.57 ± 0.10, 0.55 ± 0.09, 0.88 ± 0.13, 1.08 ± 0.17, 1.05 ± 0.18 and 0.49 ± 0.09, respectively. Two-way ANOVA revealed significant effects of different ferrule heights and crown-to-root ratios on the fracture resistance (P < 0.001), but no difference in fracture resistance between two post-and-core systems (P = 0.973). The highest fracture strengths of the specimen were found with the ferrule length of 1.92 mm in group FP and 2.07 mm in group MP, the crown-to-root ratio of which in 0.90 and 0.92 respectively., there is a significant difference in fracture modes among the groups(P < 0.05). Conclusions When a certain height of ferrule is prepared and a cast metal or fiber post-and-core system is restored for the residual root, the clinical crown-to-root ratio of the tooth after restoration should be kept within 0.90 to 0.92, so as to improve the fracture resistance of endodontically-treated mandibular first premolars.

Evaluation of mechanical properties of different polyetheretherketone endodontic post systems: An in vitro study

Abstract: Abstract Background Survival of endodontically treated teeth depends on efficiently restoring the missing tooth structure. Objectives This study is designed to assess the mechanical properties of different endodontic post systems. Materials and methods Human permanent maxillary central incisors (no.=58) of the same size were decorated and root-filled, and the post spaces were prepared up to 9.0 mm. Then, the specimens with prepared root canals were randomly divided into two groups; Group P allocated a prefabricated polyetheretherketone (PEEK) post and composite core, while Group C allocated a custom-made post-core of PEEK. The cementation of the posts was carried out using self-adhesive resin cement, while the nano-hybrid composite resin was used for core fabrication. After cementation, the specimens from each group were randomly divided into two subgroups according to the types of tests utilized. Of these, 28 samples (14 from each group) were for the fracture strength test, which was restored with IPS e-max CAD crown, and 30 samples (15 from each group) for the pullout resistance test. A universal testing machine was used for the test performance. Results The fracture resistance test showed that the values were significantly different among tested posts ( P = 0.013). Group P showed the highest fracture resistance. The custom-made one-piece post and core PEEK post group (C) exhibited higher mean values of pullout resistance compared with the other group (P) ( P = 0.059). In the two-piece PEEK post and composite core, the predominant type of failure was core displacement or fracture, while in the one-piece PEEK post-core, most types of losses were either in the crown or in the post. Conclusions The prefabricated posts are more resistant to fracture than the custom-made posts with fracture and displacement mainly of the core. In contrast, both showed similar pullout resistance.

Prosthetic Rehabilitation of Endodontically Treated Tooth by Using CAD-CAM Milled Zirconia Post and Core System: A Clinical Report

Abstract: Background: Maxillary central incisor is the most commonly affected tooth during trauma followed by maxillary lateral incisor and mandibular incisors. Trauma to the anterior tooth requires urgent care because of the essentiality of preserving the natural tooth. When a complicated crown a fracture takes place, it necessitates endodontic treatment and restoration of a fractured crown segment with post in the canal. This case report describes a patient with a broken central incisor and treated with a Zirconia crown. Keywords: CAD/CAM, Esthetics, Post & Core.

Guided removal of a fractured fiber post and immediate restoration with a digitally prefabricated titanium post-and-core and zirconia crown: A clinical report

Abstract: A completely digital workflow is described for the immediate restoration of a fractured fiber post with a digitally prefabricated definitive restoration using 3-dimensionally printed guides. The geometric morphology and axis of the root canal were digitally determined by using cone beam computed tomography to localize the 3-dimensional position of the fractured fiber post. A virtual drill modeled on the shape of the fractured post was fabricated and customized for removal of the post by using a guide to facilitate the intraoral transfer of the drilling procedure. A titanium post-and-core and crown had been virtually predesigned and fabricated before the procedure, and 2 digital guides were designed for their placement. All guides were 3-dimensionally printed. By following this workflow, the removal of the fractured fiber post and immediate definitive restoration were completed in 1 visit, facilitating a more efficient, predictable, and straightforward treatment.

Cumulative 10-year performance of endodontically treated teeth with prosthetic restorations of base metal alloy double crowns with friction pins-a retrospective study.

Abstract: Abstract Objectives This 120-month follow-up study aimed to investigate the complication rate of abutment teeth after endodontic pretreatment with base metal alloy double crowns with friction pins. Materials and methods A total of 158 participants ( n = 71, 44.9% women) aged 62.5 ± 12.7 years with 182 prostheses on 520 abutment teeth ( n = 459, 88.3% vital) were retrospectively analyzed between 2006 and 2022. Of the endodontically treated abutment teeth, 6.9% ( n = 36) were additionally treated with post and core reconstructions. Cumulative complication rates were calculated using the Kaplan–Meier estimator and log-rank test. In addition, Cox regression analysis was performed. Results The cumulative complication rate at 120 months for the entire set of abutment teeth was 39.6% (confidence interval [CI]: 33.0–46.2). Endodontically treated abutment teeth (33.8%; CI: 19.6–48.0) were found to have a significantly higher cumulative fracture rate than vital teeth (19.9%; CI: 13.9–25.9, p < 0.001). Endodontically treated teeth restored with post and core reconstructions (30.4%; CI: 13.2–47.6) showed a nonsignificant lower cumulative fracture rate than that of teeth with root fillings only (41.6%; CI: 16.4–66.8, p = 0.463). Conclusions Higher 120-month cumulative fracture rates were observed in endodontically treated teeth. Comparable performance was observed in teeth with post and core reconstructions compared to teeth with root fillings only. Clinical relevance If endodontically treated teeth are used as abutments for double crowns, the risk of complications from these teeth should be considered when planning treatment and communicating with the patient.

The Effect of Ferrule/Crown Ratio and Post Length on the Applied Stress and Strain Distribution to the Endodontically Treated Maxillary Central Teeth: A Finite Element Analysis

Abstract: Objectives: One of the most common methods used for the reconstruction of endodontically treated teeth is post and core and crown. Various factors such as the remaining tissue above the cutting margin (ferrule) affect the fracture resistance of teeth restored with post and core and crown. This study aimed to investigate the effect of ferrule/crown ratio (FCR) on the strength of maxillary anterior central teeth using finite element analysis. Materials and Methods: A 3D scan of a central incisor was obtained, and the data were transferred to Mimics software. Then, a 3D model of the tooth was designed. Next, 300N load was applied at a 135° angle to the tooth model. Force was applied to the model both horizontally and vertically. Ferrule height was considered to be 5%, 10%, 15%, 20%, and 25% in the palatal surface and 50% in the buccal surface. The length of post in the model was 11, 13, and 15mm. Results: By increasing the FCR, stress and strain distribution increased in the dental model and decreased in the post itself. As the horizontal angle of load application increased, the level of stress and strain created in the dental model increased as well. The closer the force application site to the incisal area, the higher the stress and strain would be. Conclusion: Maximum stress was inversely correlated with FCR and post length. In ratios of 20% and higher, insignificant changes occurred in stress and strain patterns in the dental model.

“Endocrown” A Major Paradigm Shift in Restorative Dentistry: A Case Report

Abstract: Endocrowns are a conservative and aesthetic treatment option for restoration of extensively destructed posterior teeth. Themain advantage is the fact that there is no need for imprudent preparation of the access cavity as done for post and corebuildups. Moreover, the clinical visits are less time-consuming and less frequent unlike the ones for post and core buildupsand subsequent crown preparation. This case report features the case of a coronally damaged maxillary first molar treatedby zirconium endocrown following endodontic treatment

Comparison of fracture resistance of endodontically treated teeth restored with different aesthetic post and core systems under all ceramic restoration luted with two types of cements.

Abstract: Context Fracture of endodontically treated teeth is a grave sequela that a clinician should seriously ponder. Suitable selection of restorative materials is a requisite for long-term clinical success. Aims To compare the fracture resistance of endodontically treated teeth restored with three different posts luted using two different cements under all ceramic crowns. Settings and Design This in vitro study was conducted in the Department of Prosthodontics, Government Dental College, Kottayam, Kerala, India. Methods and Material Thirty endodontically treated single-rooted mandibular premolars in which post spaces were prepared and divided into three different groups. Group 1 (n = 10): zirconia post group. Group 2 (n = 10): quartz fibre post group. Group 3 (n = 10): glass fibre post group. Each group is sub-divided into two based on the luting system: resin-modified glass ionomer cement (RMGIC) or dual-cure resin cement (DCRC). The fracture resistance testing was performed in a universal testing machine with a crosshead speed of 0.5 mm/min. Statistical Analysis Used The mean fracture resistance were analysed using independent sample Student t-test and one-way ANOVA. Results : Within the zirconia post group, the mean fracture resistance was higher in DCRC sub-group compared to the RMGIC sub-group and the difference was statistically significant (p = 0.017). The difference in fracture resistance between three different post systems was not found to be statistically significant with respect to both the luting systems. Conclusions It was observed that when zirconia post is used, the mean fracture resistance was higher in dual-cure resin group compared to the resin-modified GIC group.

Microleakage Assessment of CAD/CAM Endo Crown Restorations (an in vitro Study)

Abstract: : The preservation of tooth structure is an important factor in the successful restoration of endodontically treated teeth. The loss of structural integrity increases the occurrence of crown fractures and microleakage at the margins of restorations in endodontically treated teeth compared with vital teeth. A total of twenty endocrowns were fabricated in this study and the endocrown was divided into two main groups. Each subgroup was tested after cementation for (marginal gap and fracture strength). To simulate a frequent clinical situation then accept a different type of end crown restoration (IPS E-max cad, IPS E-max press). IPS E-max comprises highly esthetic, high strength materials for both the press and CAD/CAM technology subgroup recorded statistically significant (p<0.05) highest marginal gap mean value (54.85±2.5 μm) followed by O group P subgroup (52.00±4.3 μm) then N group P subgroup (49.47±1.3 μm). CAD/CAM endocrown restoration is better in marginal fit. Microleakage is directly affected by the type of cement of CAD/CAM endocrown. Ceramic endocrown is considered a recent approach in the treatment of endodontically treated teeth with the advantage of the reduction in the amount of loss of tooth structure in comparison to the classical crown with post and core.