Four-year Survival of Endodontically Treated Premolars Restored with Fiber Posts

Clinical and laboratorial performance of rehabilitation of endodontically treated teeth: A systematic review

OBJECTIVE

This systematic review aimed to analyze the clinical (survival rate, failure risk, or fracture) and laboratory performance (fracture mode or failure) of rehabilitations of endodontically treated teeth, with and without posts.

MATERIALS AND METHODS

A systematic search was conducted in the Pubmed, Scopus, Web of Science, Embase, Cochrane Library, and OpenGrey databases up to March 2023, according to PRISMA guidelines. In vitro and clinical studies that compared the clinical and laboratory performance of endodontically treated teeth with and without intraradicular posts were included. Studies selection, data extraction, and risk of bias analysis were performed.

RESULTS

Thirty-one in vitro and 7 clinical studies were included. For in vitro studies, fiberglass post (n = 24) was the most mentioned. The follow-up time of the clinical studies ranged from 1 to 17 years, with the fiber-reinforced composite post (n = 3) being the most evaluated, and only failure risk proved to be more favorable for using intraradicular posts.

CONCLUSION

Rehabilitations of endodontically treated teeth with and without intraradicular retainers showed no difference in fracture resistance and failure mode, evaluated by in vitro studies. Clinical studies showed no difference in survival rate, but failure risk proved to be more favorable for the use of posts.

CLINICAL SIGNIFICANCE

This analysis revealed significant variability between results, however, most laboratory and clinical studies revealed no difference with using the post. Furthermore, it is important to emphasize the need to evaluate the coronary remnant and the general characteristics of the tooth in each situation.

Outcome measurements and quality of randomized controlled clinical trials of tooth-supported fixed dental prostheses: A systematic review and qualitative analysis

STATEMENT OF PROBLEM

The lack of consensus regarding a standardized set of outcome measurements and noncompliance with current reporting guidelines in clinical trials of tooth-supported fixed dental prostheses (FDPs) hamper interstudy comparability, compromise scientific evidence, and waste research effort and resources in prosthetic dentistry.

PURPOSE

The primary objective of this systematic review was to identify all primary and secondary outcome measurements assessed in randomized controlled trials (RCTs) of tooth-supported FDPs. Secondary objectives were to assess their methodological quality by using the Cochrane Collaboration's risk of bias tool (RoB, v2.0) and their reporting quality by means of a standardized 16-item CONSORT assessment tool through published reports.

MATERIAL AND METHODS

An electronic search was conducted in MEDLINE, EMBASE, and Cochrane library to identify all RCT-related articles published in the past 10 years. Differences in RoB were tested with the Pearson chi-squared test, and those in CONSORT score with the Student t test.

RESULTS

A total of 64 RCTs from 79 publications were deemed eligible. The diversity of outcome measures used in the field is apparent. Twenty percent of the included studies had a low RoB, 79% showed some concerns, and 1% had a high RoB. The mean ±standard deviation CONSORT compliance score was 22.56 ±3.17. Trials adhered to the CONSORT statement reported lower RoB than those that did not adhere (P<.001). RCTs with a low RoB reported more comprehensive adherence to CONSORT guidelines than those with some concerns (MD 4 [95% CI 1.52-6.48]; P=.004).

CONCLUSIONS

A standardized core outcome reporting set in clinical research on tooth-supported FDPs remains evident. Adherence to the CONSORT statement continues to be low, with some RoB concerns that can be improved.

Influence of remaining coronal tooth morphology with resin abutment and fiber post on static and dynamic fracture resistances

This study aimed to clarify the fracture resistance of resin abutments built on endodontically treated roots with the remaining coronal teeth via static and cyclic loading tests. Endodontically treated bovine roots, which had a remaining coronal tooth covered with an occupied area for a quarter and half of the circumference at the tensile side or covered the circumference at both the tensile and compressive sides, were fabricated to build up to the resin abutment. Fracture resistance was evaluated via static and cyclic loading tests by applying a load of 30° to the tooth axis. Half of the circumference of the remaining coronal tooth showed a significantly higher static fracture load and survival rate. The remaining coronal tooth on the compressive side improved the dynamic fracture resistance associated with severe fractures. The occupied area and location of the remaining coronal tooth affected the static and dynamic fracture resistances.

How long must a post be? A retrospective survival analysis on a large cohort with long follow-ups

OBJECTIVES

Post and core (PC) is frequently used, but clinical evidence concerning how long a post must be is scarce. Recommendations in dental literature range from half of the root which should be incorporated, to post space preparations conducted as deep as possible increasing the risk for root perforation thus tooth loss. Therefore, the aim of this retrospective survival analysis is to evaluate the post length as well as the post-clinical crown ratio on a large patient cohort with long follow-ups.

MATERIALS AND METHODS

Overall 1026 PC in 731 patients could be included in this study (2004-2023). The files were analysed due to the parameters post length and post-clinical crown ratio on X-Ray. Furthermore, the influence of the type of covering prosthetic restoration, location, type of tooth, luting material, PC material, bone attachment and therapist was evaluated. The statistical analysis was assessed using Kaplan-Meier (univariate influences) and Cox regression (multifactorial influences).

RESULTS

Survival until extraction as well as decementation was significantly influenced by bone attachment and covering prosthetic restoration. Posts reaching the middle third of the root showed highly significant (p < 0.001) better survival probabilities than those reaching the coronal or apical third. Regarding the post-clinical crown ratio, no significant difference was found for post = crown/post > crown, whereas post

CONCLUSIONS

The post space preparation should not be extended over the middle third of the root, but has to be deep enough to ensure that the post is at least as long as the clinical crown.

CLINICAL SIGNIFICANCE

Against the background of the large sample size and the long follow-ups, the results of this retrospective survival analysis are suitable to give general recommendations regarding how long a post has to be in order to ensure the best survival probability for PC treatment.

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Key Words

• Cox regression
• Kaplan-Meier analysis
• Post length
• Post-clinical crown ratio
• Survival time

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MESH Headings

• Humans
• Retrospective Studies
• Follow-Up Studies
• Post and Core Technique
• Dental Restoration Failure
• Crowns
• Survival Analysis

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Affiliation(s)

Sarah Marie Reich Justus Liebig University, Dental Clinic - Department of Prosthodontics, Schlangenzahl 14, 35392 Giessen, Germany
Kay-Arne Walther Justus Liebig University, Dental Clinic - Department of Prosthodontics, Schlangenzahl 14, 35392 Giessen, Germany
Bernd Wöstmann Justus Liebig University, Dental Clinic - Department of Prosthodontics, Schlangenzahl 14, 35392 Giessen, Germany
Peter Rehmann Justus Liebig University, Dental Clinic - Department of Prosthodontics, Schlangenzahl 14, 35392 Giessen, Germany
Jonas Adrian Helmut Vogler Justus Liebig University, Dental Clinic - Department of Prosthodontics, Schlangenzahl 14, 35392 Giessen, Germany.

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Evaluation of stress distribution on an endodontically treated maxillary central tooth with lesion restored with different crown materials: A finite element analysis

Objectives

The biomechanical response of teeth with periapical lesions that have been restored using various substructure materials, as well as the stress mapping in the alveolar bone, has not been thoroughly described. In this context, the objective of this study is to investigate the structural stress distributions on root canal-treated maxillary right central incisors with lesions restored using different crown materials under linear static loading conditions through finite element analysis (FEA).

Methods

In the study, five FEA models were utilised to represent healthy teeth and teeth restored with different substructure materials: (A) a healthy tooth, (B) a lesioned, root canal-treated, composite-filled tooth, (C) a lesioned, fiber-posted, zirconia-based crown, (D) a tooth with lesions, a fiber post, and Ni-Cr infrastructure crown, (E) a tooth with a lesion, a fiber post, and an IPS E-max infrastructure crown. A force of 100 N was applied at an angle of 45° to the long axis of the tooth from 2 mm cervical to the incisal line on the palatal surface. Deformation behaviour and maximum equivalent stress distributions on the tooth sub-components, including the bony structure for each model, were simulated.

Results

Differences were observed in the stress distributions of the models. The maximum stress values of the models representing the restorations with different infrastructures varied, and the highest value was obtained in the model of the E-max crown (Model E: 136.050 MPa). The minimum stress magnitudes were obtained from Model B the composite-filled tooth (80.39 MPa); however, it was observed that the equivalent stresses in all the models showed a similar distribution for all components with varying magnitudes. In periapical lesion areas, low stresses were observed. In all models, the cervicobuccal collar region of the teeth had dense equivalent stresses.

Conclusion

Different restorative treatment methods applied to root canal-treated teeth with periapical lesions can impact the stress in the alveolar bone and the biomechanical response of the tooth. Relatively high stress values in the cortical bone at the cervical line of the tooth have been observed to decrease towards the apical region. This observation may suggest a potential healing effect by reducing pressure in the periapical lesion area.

Clinical significance

Composite resin restorations can be considered the first-choice treatment option for the restoration of root canal-treated teeth with lesions. In crown restorations, it would be advantageous to prefer zirconia or metal-supported prostheses in terms of biomechanics.

Biomechanical performance of endocrown and core-crown restorations: A systematic review

OBJECTIVE

To assess and compare, through a systematic review of the literature, the biomechanical performance of endocrowns and traditional core-crowns (with and without intracanal post) for the rehabilitation of endodontically treated teeth with severe coronal structure damage.

MATERIALS AND METHODS

A systematic search was performed in MEDLINE/PubMed, Scopus, and Web of Science databases. In-vitro studies comparing endocrowns with (post-)core-crown restorations were selected and screened by two independent reviewers. The included studies were submitted to the risk of bias analysis using the RoBDEMAT tool and the biomechanical outcomes were collected for qualitative analysis. The extracted data were presented based on comparative analyses among the included studies.

RESULTS

Thirty-one studies were included: 9 studies evaluated restorations of molars, 14 for premolars, and 8 studies evaluated anterior restorations. For the majority of the studies, endocrowns showed either similar or greater survival rates under fatigue and monotonic load than (post-)core-crown restorations, irrespectively of the tooth. The endocrowns showed more favorable failure patterns than (post-)core-crowns, irrespectively of the tooth. Endocrowns produced lower stresses in the restorative material for molars and premolars and in the luting material for premolars than (post-)core-crown restorations. The included studies presented adequate information for most items of the RoBDEMAT risk of bias tool.

CONCLUSION

Endocrowns showed similar or greater biomechanical performance than the traditional (post-)core-crown restorations in most of the evaluated studies.

CLINICAL SIGNIFICANCE

This systematic review showed that endocrowns present either similar or greater biomechanical performance than core-crown restorations for anterior and posterior endodontically treated teeth with severe structural damage.

Effect of a circumferential ferrule on the survival and success of endodontically treated teeth restored with fiber posts: A systematic review and meta-analysis

STATEMENT OF PROBLEM

The success of endodontically treated teeth (ETT) is influenced by factors that include the use of prefabricated glass fiber posts. A consideration for success is the presence of a circumferential ferrule, but systematic reviews and meta-analyses are lacking.

PURPOSE

The purpose of this systematic review and meta-analysis was to assess the impact of the presence or absence of a circumferential ferrule on the survival and success rates of ETT restored with prefabricated fiber posts.

MATERIAL AND METHODS

Adhering to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines, a comprehensive search of the major scientific literature databases was conducted. Eligible studies included randomized clinical trials and prospective cohort studies with a minimum 6-month follow-up, focusing on ETT restored with fiber posts either with or without a uniform circumferential ferrule. Relative risks (RRs) and 95% confidence intervals (CIs) were calculated to compare outcomes. The degree of variability among studies was assessed using the chi-squared test (α=.05).

RESULTS

Of 3731 identified records, 8 were eligible for inclusion. Direct analysis of success rates (2 studies, 123 teeth) showed a significant increase in success when a uniform circumferential ferrule was present (RR=1.28, 95% CI: 1.06, 1.54, P<.05). However, indirect analysis of survival and success rates (8 studies, 407 teeth) indicated no significant differences in outcomes between the ferrule and no ferrule groups (P>.05).

CONCLUSIONS

The results of this systematic review and meta-analysis determined that a uniform circumferential ferrule had a positive effect on the success rates of ETT restored with prefabricated fiber posts. However, further high-quality studies are required to provide more robust evidence and to allow potential confounding factors to be considered.

Effect of silicone-based sealers on fiber post retention: An in vitro study

PURPOSE

The effect of a silicone-based sealer on fiber post retention has not been the subject of research and remains unclear. This study aimed to evaluate and compare the impact of a silicone-based sealer and an epoxy resin sealer on fiber post retention.

MATERIAL AND METHODS

Forty extracted human mandibular premolars that were caries-free, single-rooted, and possessed straight single canals were the specimens of the present study. Teeth were randomly divided into two groups (n = 20 each). All specimens were prepared using gutta-percha. The sealer used in the first group was Guttaflow 2, while AH26 was used in the second group. Post spaces were prepared immediately after obturation for each specimen. Prefabricated fiber posts were luted in both groups using a self-adhesive resin cement (RelyX-U200). Each specimen was vertically secured using a universal testing machine (Instron Corp.) and a constant pull-out force at a loading rate of 0.5 mm/min was applied until the point of dislodgement. Data were analyzed using t-tests.

RESULTS

A significant difference was found between the mean of maximum loads of the silicone-based sealer and epoxy resin sealer groups (p = 0.0001). The mean maximum load for the epoxy resin sealer group was 194.62 N, while that for the silicone-based sealer group was 111.64 N.

CONCLUSION

Fiber post retention in teeth obturated using silicone-based sealer was inferior to that in teeth obturated with epoxy resin sealer. Therefore, the sealer used during obturation can significantly affect fiber post retention.

Survival of teeth treated with post and core - A retrospective study of more than 1000 cases with observation periods up to 18 years

OBJECTIVES

Even if survival of post and core (PC) itself was frequently investigated in recent literature, clinical data concerning the risk for extraction of teeth restored with PC is still scarce. Since most authors found the loss of retention of refitable post and cores as the most common cause of failure, it is impossible to draw a conclusion on tooth survival on the results of those studies. Therefore, the aim of the present study was to improve the clinical evidence on the survival of teeth treated with post and cores on a large number of cases over a long observation period.

MATERIALS AND METHODS

735 patients were treated with 1053 post and cores in the observation period (2004-2022) and could be included in the study. The patient files were analysed due to the parameters: Type of covering prosthetic restoration, location, type of tooth, luting material, post and core material, bone attachment and therapist. The survival probability was assessed using Kaplan-Meyer analysis. Cox regression was used to assess possible multifactorial influences.

RESULTS

The overall average survival time until necessary extraction of a tooth restored with a post and core was 11.74 years. A root fracture in primary crown retained removeable partial dentures (RPDs) during the first five years was the most common reason for extraction in this study. A significant influence on the survival time of teeth restored with post and cores was found for the type of covering restoration, bone attachment, age of the patient and post and core material.

CONCLUSIONS

Post and core restored teeth should be avoided as abutments for primary crown retained RPDs.

CLINICAL SIGNIFICANCE

If it is inevitable to utilise post and core restored teeth for primary crown retained RPDs, post and core materials with matching mechanical properties to that of dentine should be preferred.

Evaluation of Poly(etheretherketone) Post's Mechanical Strength in Comparison with Three Metal-Free Biomaterials: An In Vitro Study

The thinking about metallic replacement has begun in a global context of reducing metallic alloys' use in odontology. Among the materials proposed for their replacement, poly(etheretherketone) may present interesting properties, especially in removable dentures' frames. The purpose of this study is to evaluate fracture resistance of PEEK posts-and-cores compared to non-metallic CAD/CAM materials and fiber glass posts. Forty extracted maxillary central incisors were prepared to receive posts. Samples were divided into four groups depending on whether they had been reconstructed with LuxaCam® PEEK, Enamic®, Numerys GF® or LuxaPost®. Samples were submitted to an oblique compressive test and results were statistically analyzed with ANOVA and Student's tests (or non-parametric tests depending on the conditions). Glass fiber posts and Numerys GF® reveal a significantly higher fracture resistance than LuxaCam® PEEK and Enamic®. No exclusively dental fracture has been noted for the Enamic group, which significantly distinguishes these samples from the three other groups. In our study, it appears that the conception of posts and cores with hybrid ceramic never conducts to a unique tooth fracture. By weighting the results according to the materials used, our data, obtained for the first time on this type of PEEK block, cannot confirm the possibility of using PEEK for inlay-core conception, excepted for specific cases when the material is considered in a patient presenting allergies or systemic disease contraindicating resin or metal.

Particulate Filler and Discontinuous Fiber Filler Resin Composite's Adaptation and Bonding to Intra-Radicular Dentin

The aim of this study was to assess adaptation and bonding to root canal dentin of discontinuous (short) glass fiber-reinforced composite to intra-radicular dentin (DSGFRC).

METHODS

Seventy virgin human teeth were extracted and then endodontically treated; then samples were randomly divided into 7 groups (n = 10), based on the materials' combinations as follows: Group 1, a two-bottle universal adhesive + DSGFRC; Group 2, a single-component universal adhesive + DSGFRC; Groups 3 and 4, the same materials of Goups 1 and 2 were used but after cleaning of the canal walls with 17% EDTA and final irrigation with 5.25% NaOCl Ultrasound Activated (UA); Group 5, traditional prefabricated fiber posts were luted after being silanized with G-Multi Primer; Groups 6 and 7, like Group 5 but after ultrasonic irrigation (UA). All sample roots were cut 1 mm thick (n = 10) to be evaluated regarding root canal adaptation using a light microscope and scanning electron microscope (SEM) and push-out bond strength. These results were statistically analyzed by Kruskal-Wallis analysis of variance by ranks. The level of significance was set at p < 0.05.

RESULTS

Bond strength forces varied between 6.66 and 8.37 MPa and no statistically significant differences were recorded among the groups. By microscopic examination, it was noted that ultrasonic irrigation increased the adaptation of the materials to the dentin surface.

CONCLUSIONS

Within the limitations of this in vitro study, it may be concluded that when DSGFRC was used for intracanal anchorage in the post-endodontic reconstruction, similar push-out retentive force and strength to those of traditional fiber posts cemented with particulate filler resin composite cements were achieved.

Evidence-based fact checking for selective procedures in restorative dentistry

OBJECTIVES

Similar to other dental specialties, there are many clinical procedures in restorative dentistry that may or may not be supported by good evidence. Thus, the effectiveness of these procedures is uncertain. The aim of this paper is to reduce this knowledge gap by critically inspecting selective procedures in restorative dentistry and exploring if these well-established or widely advocated treatment modalities are necessary for improving treatment outcomes based on the best available evidence.

MATERIALS AND METHODS

A MEDLINE search was conducted to identify research on selective procedures while focusing on clinical trials and systematic reviews. Due to their practical relevance in the decision-making process, cost-effectiveness analyses were also included.

RESULTS

Mixed results were identified regarding the included interventions. Some procedures had adequate evidence supporting them while others were mostly based on beliefs.

CONCLUSIONS

A critical review of the available literature indicates that some common restorative procedures lack adequate support from high-quality research evidence.

CLINICAL RELEVANCE

This paper attempts to highlight the need to critically examine the scientific validity of traditional knowledge and techniques through the context of current research evidence. This will not only help generate consensus between educators, clinicians, and researchers regarding restorative procedures but will also lead to improved patient care and outcomes.

The Influence on Fracture Resistance of Different Composite Resins and Prefabricated Posts to Restore Endodontically Treated Teeth

Recent formulations of resin-based composites have incorporated different combinations of materials. However, the mechanical and bonding behavior of these materials with intraradicular posts are unclear. This study aimed to evaluate the effect of light-cure and dual-cure resin composite posts on the fracture resistance of endodontically-treated teeth. Materials and Methods: Ninety extracted human upper canines were selected and randomly divided into nine groups (n=10): (G1) endodontically treated teeth without endodontic posts; (G2) glass-fiber post cemented with glass-ionomer cement; (G3) endodontic post by dual-cure composite resin (Rebilda DC); (G4) endodontic post by dual-cure composite resin (Cosmecore); (G5) endodontic post by dual-cure composite resin (Bis-Core); (G6) endodontic post by light-cure composite resin; (G7) glass-fiber post customized with flowable composite resin; (G8) glass-fiber post cemented with light-cure composite resin; (G9) glass-fiber post cemented with self-adhesive resin cement. After the post insertion, all specimens were subjected to mechanical (250,000 cycles) and thermocycling (6000 cycles, 5 °C/55 °C) and immediate loading at 45 degrees in a universal testing machine until fracture. The data were analyzed by one-way ANOVA and multiple comparisons using the Fisher LSD Method (p < 0 05). Results: The mean failure loads (±SD) for the groups ranged from 100.7 ± 22.6 N to 221.9 ± 48.9 N. The G1 group (without endodontic posts) had a higher fracture strength than all experimental groups (p < 0.001). Conclusions: Within the limitations, the light- and dual-cure post technique did not present lower fracture resistance values as compared to the conventional glass-fiber post.

Comparative Evaluation of Different Post Materials on Stress Distribution in Endodontically Treated Teeth Using the Finite Element Analysis Method: A Systematic Review

The aim of this systematic review is to summarize and conclude findings to reveal the stress ranges developed by various post materials by finite element analysis. This, in turn, aids in the selection of better post material clinically. The electronic databases PubMed and Google Scholar were searched in this review by using specific inclusion and exclusion criteria. Among 14586 articles, 22 articles were included in this systematic review, as they satisfied the eligibility criteria. The search covered all articles published from 1997 to December 2021. All records identified were retrieved and imported into the Rayyan bibliographic software, which is a systematic review screening software. Later, data extraction and analysis of 22 articles were done. Twenty-two articles, which were all finite element analysis studies, were included. Among these, 18 studies used maxillary central incisor scanned models, two studies used a maxillary canine model, and the remaining two used the mandibular premolar model for finite element analysis. All these tooth models are restored with post models made of different materials. This systematic review revealed a difference in stress distribution in endodontically treated teeth when using different post materials. Among 22 studies, 15 studies evaluated glass fiber posts and the results showed that they induce less stress on restored endodontically treated teeth when compared to other posts, with maximum stress concentration at the cervical third of the root. Prefabricated posts like stainless steel and Titanium showed more stress on the restored tooth structure with stress concentration at the cervical and apical third of the root. Prefabricated zirconia also showed more stress on the restored tooth with maximum stress concentration at the middle third of the root.

Survival Rates of Endodontically Treated Posterior Teeth Restored with All-Ceramic Partial-Coverage Crowns: When Systematic Review Fails

Background: To determine the survival rates of endodontically treated posterior teeth (EDPT) restored with partial coverage all-ceramic crowns with or without the use of fiber posts. Methods: MEDLINE and Cochrane searches were conducted in order to identify Randomized Clinical Trials (RCTs) related to endodontically treated posterior teeth restored with partial coverage crowns. The search period was extended until February 2020 and only in vivo, human, and studies in the English language were included. A manual search was also conducted and additional articles, if found, were included in the database. Results: The initial search for the selected databases identified 495 studies, which were all screened for inclusion through titles, abstracts and full-text reading. Out of these 495 studies, only one article met the eligibility criteria and was included in this systematic review. Statistical analysis could not be performed. Conclusions: Only one RCT was identified in this systematic review. More clinical evidence is necessary to assess the survival rate of EDPT with partial-coverage crowns. This systematic review failed because it did not find scientific evidence to support the use of indirect bonded restorations on EDPT.

Influence of remaining axial walls on of root filled teeth restored with a single crown and adhesively bonded fibre post: A systematic review and meta-analysis

OBJECTIVES

To synthesise evidence on structural failures and prevalence of post-treatment endodontic disease (PTD) in anterior and posterior root filled teeth with a single crown and adhesively bonded fibre post with regards to the number of axial walls.

DATA

An electronic search was performed, no language constraints or restriction on the year of publication were applied.

SOURCES

PubMed, Medline, Cochrane and Scopus on 13th of July 2021.

STUDY SELECTION

Clinical studies that reported the remaining number of axial walls for permanent anterior and posterior root filled teeth (RFT) restored with single crowns and adhesively bonded fibre posts with a minimum of 1 year follow-up were included. Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines [1] were used. The number of axial walls and the success/failures were analysed as follows: fibre post and/or core decementation, post and/or core fracture and post treatment endodontic disease, and root fracture.

CONCLUSIONS

A total of 811 studies were identified with 5 meeting the inclusion criteria. The two randomized controlled trials included had 'some concerns' as determined by the Cochrane risk-of-bias 2 tool while the Newcastle-Ottawa scale found low risk of bias for the remaining three studies. The random effects model for subgroup meta-analysis revealed failures for posterior RFT increased with decreasing numbers of remaining walls. Failures for 0 remaining walls were 23% (95% CI = 10% - 36%) and for one remaining wall 15% (CI: 3% -26%), irrespective of follow-up times. Fibre post debonding and PTD increased with decreasing numbers of walls. Relative & catastrophic failure of posterior teeth restored with a fibre post and single crown after root canal treatment increased with decreasing numbers of remaining axial walls.

CLINICAL SIGNIFICANCE

This synthesis is unique as it minimizes the presence of confounding factors by reviewing evidence of failures and post-treatment endodontic disease associated with teeth restored with single crowns. Therefore, it provides valuable predictive evidence of potential coronal restoration catastrophes and post-treatment endodontic disease associated with root filled teeth.

Impact of different surface treatment methods on bond strength between fiber post and composite core material

PURPOSE

To assess the impact of different surface treatments on the push-out bond strength between fiber post and a composite resin core material.

MATERIAL AND METHODS

Seventy-two glass-fiber posts were randomly assigned into six groups according to the method of surface treatment: Control (no treatment), silane, sandblasting, hydrofluoric acid, hydrogen peroxide, and hydrogen peroxide with sandblasting. Two posts from each group were inspected under a scanning electron microscope to assess the surface modifications and 10 posts were employed for the push-out test. Each post was placed vertically in the middle of a cylindrical putty matrix and a dual-cure composite resin material was applied for core build-up. Two discs of each specimen were cut using a low-speed diamond saw (total 120 discs). The push-out test was executed using a universal testing machine at a crosshead speed of 0.5 mm/min. Statistical analysis was performed using one-way ANOVA and Tukey's test (p ≤ 0.05). The mode of failure of each disc was evaluated under SEM.

RESULTS

The sandblasting and hydrofluoric acid groups presented significantly higher bond strength than control and hydrogen peroxide groups. The hydrogen peroxide groups exhibited significantly the lowest bond strength of all groups. There was no significant difference between the control and silane groups. All groups showed predominantly adhesive failure except the hydrogen peroxide with sandblasting, where the cohesive failure of the post was predominant.

CONCLUSIONS

Sandblasting and hydrofluoric acid surface treatments demonstrated superior results to silane and hydrogen peroxide. The combined method of hydrogen peroxide and sandblasting could weaken the fiber post and lead to clinical fractures.

Effect of epigallocatechin-3-gallate and thermal cycling on the bond strength of resin cements to the root dentin

This study evaluated the effect of epigallocatechin-3-gallate (EGCG) solution and thermal cycling on the bond strength (BS) of fiber posts to the root dentin using two different resin cements (conventional or self-adhesive). One hundred and forty-four bovine roots were endodontically treated. After post space preparation, specimens were randomly divided into six groups (n = 24) according to dentin pretreatment [distilled water, 0.05% EGCG solution or 2% chlorhexidine (CHX) solution] and resin luting agent used for fiber post cementation (RelyX ARC or RelyX U200-3 M ESPE). Then, the samples were separated into two subgroups (n = 12): storage in distilled water at 37 °C for 24 h and thermal cycling (5 °C/55 °C, dwell time 30 s-12,000 cycles) during 6 months. After that, the specimens were subjected to the pull-out BS test (Universal Testing Machine-0.5 mm/min) and the failures pattern was analyzed in a stereomicroscope. According to the BS results (three-way ANOVA, Tukey's test, α = 0.05), the highest values were reported in the group EGCG + RelyX U200, showing significant statistical differences compared to all the other experimental groups. For Control and CHX groups BS values, there was no significant difference (p > .05) between the resin cements. For conventional resin cement, there was no significant difference among treatment solutions (p > .05). The thermal cycling did not influence the BS results (p > .05). As reported by the failure mode analysis, adhesive failure was predominant in all groups. EGCG solution improved the bond strength of self-adhesive resin cement to root dentin.

The restoration of root filled teeth: a review of the clinical literature

Clinicians often face dilemmas regarding the most appropriate way to restore a tooth following root canal treatment. Whilst there is established consensus on the importance of the ferrule effect on the predictable restoration of root filled teeth, other factors, such as residual tooth volume, tooth location, number of proximal contacts, timing of the definitive restoration and the presence of cracks, have been reported to influence restoration and tooth survival. The continued evolution of dental materials and techniques, combined with a trend towards more conservative endodontic-restorative procedures, prompts re-evaluation of the scientific literature. The aim of this literature review was to provide an updated overview of the existing clinical literature relating to the restoration of root filled teeth. An electronic literature search of the PubMed, Ovid (via EMBASE) and MEDLINE (via EMBASE) databases up to July 2020 was performed to identify articles that related the survival of root filled teeth and/or restoration type. The following and other terms were searched: restoration, crown, onlay, root canal, root filled, post, clinical, survival, success. Wherever possible, only clinical studies were selected for the literature review. Full texts of the identified articles were independently screened by two reviewers according to pre-defined criteria. This review identifies the main clinical factors influencing the survival of teeth and restorations following root canal treatment in vivo and discusses the data related to specific restoration type on clinical survival.

Influence of post material, post diameter, and substance loss on the fracture resistance of endodontically treated teeth: A laboratory study

STATEMENT OF PROBLEM

The influence of the flexural modulus of prefabricated posts on the fracture resistance of endodontically treated teeth is unclear.

PURPOSE

The purpose of this in vitro study was to evaluate the influence of post material and post diameter on the fracture resistance of endodontically treated mandibular premolars. In addition, the influence of tooth substance loss was evaluated by comparing 1 with 2 residual dentinal walls.

MATERIAL AND METHODS

Sixty-four extracted mandibular first premolars were endodontically treated and divided into 8 test groups (n=8) based on the number of residual walls (1 or 2), post material (glass fiber or titanium) and post diameter (International Standards Organization [ISO] 70 or ISO 90). After luting the posts, the specimens received a composite resin core and a crown preparation with a 2-mm ferrule. Cast Co-Cr crowns were cemented with glass ionomer cement. After 1 200 000 mastication cycles with a load of 49 N and simultaneous thermocycling (5 °C-55 °C), specimens were quasistatically loaded at 30 degrees to the longitudinal axis of the tooth until fracture. Fracture loads were analyzed by using 3-way ANOVA (α=.05). Fracture modes were examined with a stereomicroscope at ×25 magnification and recorded.

RESULTS

Fracture loads ranged from 954 ±35 N (1 residual wall-glass fiber-ISO 70) to 1286 ±202 N (1 residual wall-glass fiber-ISO 90). Titanium posts showed a statistically significant higher fracture resistance than glass fiber posts. A statistically significant increase in fracture resistance was also observed with increasing post diameter. However, no significant difference was found with respect to the number of residual walls (P>.05).

CONCLUSIONS

Teeth restored with titanium posts exhibited higher fracture resistance than teeth restored with glass fiber posts, especially when smaller diameter posts were used.

Endodontically treated posterior teeth restored with or without crown restorations: A 5-year retrospective study of survival rates from fracture

AIM

The aim of the present study was to investigate survival rates from fracture of endodontically treated posterior teeth (ETT) restored with or without crowns with recall periods of up to 5 years.

METHODS

ETT with single-unit crown or resin composite restorations were studied based on the inclusion criteria. Restoration, tooth structure loss, adjacent teeth, fracture, and restorability were recorded. Survival rates from fracture were calculated, and risk factors were identified.

RESULTS

Overall, survival rate of ETT with crowns (92.2%) was significantly higher than resin composites (77.4%) (P < 0.05). ETT with one or two surface loss/es and two adjacent teeth had a high survival rate of 86.9%, which was not significantly different to ETT with crowns (P ≥ 0.05). Restoration and adjacent teeth were identified as significant factors. The majority of fractured ETT with resin composites were restorable, whereas those with crowns were unrestorable. Survival rates from unrestorable fracture were not significantly different between the crown (93.1%) and resin composite (96%) (P ≥ 0.05).

CONCLUSIONS

The survival rate from the fracture of ETT restored with crowns was significantly higher than ETT restored with resin composites, but was not significantly different to ETT with one or two ETT with one or two surface loss/es and two adjacent teeth. ETT restored with resin composites had mostly restorable fracture, whereas ETT with unrestorable fracture were similar between the two restorations.

Patients' self-report on post-retained restoration is more valuable than expected! Explorative analysis of an 11-year follow-up

Objective: Assessment of long-term clinical data regarding post-endodontic restorations is essential for the evaluation of different post-and-core concepts. The aim of the present study was to assess the diagnostic accuracy of patient self-reporting on post-endodontic restorations after 11 years of clinical service.Materials and methods: Twenty-nine patients (61 ± 15 years old) with endodontic glass-fibre and titanium post-endodontic restorations were examined within the 11-year follow-up of a randomized controlled trial. Restorations were assessed by self-reports during a telephone interview (one item), the completion of a four-item questionnaire and clinical and radiographic examination. A gold standard for restoration in situ or 'failure' was defined by clinical and radiographic examination. Diagnostic accuracy of patients' self-reports was evaluated by calculating the sensitivity, specificity, and positive (PPV) and negative predictive values (NPV).Results: After a mean observation time of 137 months (min/max: 125/154 months), 25 (86.2%) restorations were in situ and 4 (13.8%) failures were detected. Self-report during a telephone interview and the four-item questionnaire correctly identified all in situ restorations (specificity = both 100%, NPV = 92.6%/96.2%). Self-report during a telephone interview identified two out of four failures (sensitivity = 50%, PPV = 100%), and self-report on the four-item questionnaire identified three out of four failures (sensitivity = 75%, PPV = 100%).Conclusions: When the clinical examination is not feasible, patients' self-report shows valuable diagnostic potential in the identification of the post-endodontic failure.

Influence of remaining coronal thickness and height on biomechanical behavior of endodontically treated teeth: survival rates, load to fracture and finite element analysis

Objective

To evaluate the effect of restorative strategy (fiber post vs cast post and core), coronal height (0 mm vs 2 mm) and thickness (higher than 1 mm vs lower than 1 mm) on survival rate, fracture resistance and stress distribution.

Material and Methods

Seventy-two bovine teeth were cleaned and allocated in six groups (n = 12). Twenty-four teeth were sectioned at 13 mm length (no remaining coronal structure) and forty-eight were sectioned at 15 mm (2 mm remaining coronal structure). Half of the forty-eight had remaining coronal thickness lower than 1 mm and the other half had thickness higher than 1 mm. All root canals were prepared at 10 mm (luting length), fiber posts were cemented in thirty-six specimens and cast post and core in other thirty-six. All teeth were restored with metallic crowns. Specimens were submitted to 1.5 million cycles (100 N, 45°, 10 Hz at 2 mm below incisal edge) and evaluated at each 500,000 cycles to detect failures. Specimens that survived were submitted to load to fracture test. Bidimensional (Rhinoceros^® 4.0) models were obteined survival data submitted to Kaplan-Meier (α=0.05) analysis and load to fracture values submitted to ANOVA and Tukey tests (α=0.05).

Results

Groups without remaining coronal structure showed survival rates lower than other groups (p=0.001). ANOVA showed higher values of load to fracture for groups with coronal thickness higher than 1 mm (p=0.0043). Finite element analysis showed better stress distribution in groups with remaining coronal structure and restored with fiber post.

Conclusion

Specimens without remaining coronal structure have lower survival rates. Specimens with remaining structure lower than 1 mm and without coronal structure support the same load to fracture value independently of the restorative strategy.

The Post-endodontic Adhesive Interface: Theoretical Perspectives and Potential Flaws

INTRODUCTION

The aim of this review was to analyze the potential of successful bonds of endodontic posts to radicular dentin as well as the limitations of the post-endodontic adhesive interface.

METHODS

The MEDLINE/PubMed and Web of Science electronic databases were searched. The search was augmented by a manual search of the pertinent bibliographies.

RESULTS

The post-endodontic adhesive interface finds application in the endodontic cohesive units. Many techniques and materials exist to improve the bond between endodontic posts and resin-based materials as well as between resin-based materials and radicular dentin. Different techniques used for the adhesion of metallic and fiber-reinforced posts are discussed and critically analyzed.

CONCLUSIONS

Although adhesive cementation of endodontic posts is popular, a long-term predictable bond may be compromised because of procedures related to the endodontic treatment and/or the adhesive cementation procedures. Microleakage and degradation phenomena may further jeopardize the post-endodontic adhesive interface.

Is the bonding of self-adhesive cement sensitive to root region and curing mode?

Objectives

To evaluate the influence of two curing techniques on the degree of conversion (DC) of resin cements and on bond strength (BS) of fiber posts in different regions of root dentin.

Material and Methods

Twenty single-rooted premolars were endodontically treated, and the post spaces were prepared. The roots were randomly divided into two groups (n=10), according to the activation mode of the resin cement RelyX™ U200 (3M ESPE Saint Paul, MN, USA): conventional (continuous activation mode) and soft-start activation mode (Ramp). The posts (WhitePost DC/FGM) were cemented according to the manufacturer’s recommendations and, after one week, the roots were cross-sectioned into six discs each of 1-mm thickness, and the cervical, medium, and apical thirds of the root canals were identified. The DC was evaluated under micro-Raman spectroscopy and the BS was evaluated by the push-out test. The data were analyzed by two-way ANOVA and Tukey’s test (α=0.05).

Results

Neither the activation mode nor the root regions affected the DC of the resin cement. Higher BS was achieved in the soft-start group (p=0.036); lower BS was observed in the apical third compared to the other root regions (p<0.001). Irrespective of the activation mode and root region, the mixed failure mode was the most prevalent.

Conclusion

The BS of fiber posts to root canals can be improved by soft-started polymerization. The DC was not affected by the curing mode.

Failure rate of single-unit restorations on posterior vital teeth: A systematic review

STATEMENT OF PROBLEM

No knowledge synthesis exists concerning when to use a direct restoration versus a complete-coverage indirect restoration in posterior vital teeth.

PURPOSE

The purpose of this systematic review was to identify the failure rate of conventional single-unit tooth-supported restorations in posterior permanent vital teeth as a function of remaining tooth structure.

MATERIAL AND METHODS

Four databases were searched electronically, and 8 selected journals were searched manually up to February 2015. Clinical studies of tooth-supported single-unit restorative treatments with a mean follow-up period of at least 3 years were selected. The outcome measured was the restorations' clinical or radiological failure. Following the Preferred Reporting Items for Systematic reviews and Meta-Analyses guidelines, the Cochrane Collaboration procedures for randomized control trials, the Strengthening the Reporting of Observational Studies in Epidemiology criteria for observational studies, 2 reviewers independently applied eligibility criteria, extracted data, and assessed the quality of the evidence of the included studies using the American Association of Critical Care Nurses' system. The weighted-mean group 5-year failure rates of the restorations were reported according to the type of treatment and remaining tooth structure. A metaregression model was used to assess the correlation between the number of remaining tooth walls and the weighted-mean 5-year failure rates.

RESULTS

Five randomized controlled trials and 9 observational studies were included and their quality ranged from low to moderate. These studies included a total of 358 crowns, 4804 composite resins, and 303582 amalgams. Data obtained from the randomized controlled trials showed that, regardless of the amount of remaining tooth structure, amalgams presented better outcomes than composite resins. Furthermore, in teeth with fewer than 2 remaining walls, high-quality observational studies demonstrated that crowns were better than amalgams. A clear inverse correlation was found between the amount of remaining tooth structure and restoration failure.

CONCLUSIONS

Insufficient high-quality data are available to support one restorative treatment or material over another for the restoration of vital posterior teeth. However, the current evidence suggests that the failure rates of treatments may depend on the amount of remaining tooth structure and types of treatment.

Complications of endodontically treated teeth restored with fiber posts and single crowns or fixed dental prostheses-a systematic review

OBJECTIVE

The present systematic review aimed at assessing data from the literature on endodontic and prosthetic complications in endodontically treated teeth restored with fiber posts and single crowns (SCs) or fixed dental prostheses (FDPs).

MATERIALS AND METHODS

Available randomized controlled clinical trials evaluating endodontic and prosthetic complications in the teeth treated with fiber posts and restored with different prosthetic restorations were reviewed. PubMed, Evidence-Based Dentistry, BMJ Clinical Evidence, Embase, DynaMed, and gray literature restricted to scientific literature were analyzed; also, manual researches were performed. English language and time filters (from 1990 to 2015) were used.

RESULTS

The database search produced 4230 records, many of which were duplicates. The manual research did not produce any other relevant article. After duplications were removed, all the selected databases produced 3670 records. Reading titles and abstracts, two independent reviewers excluded 3664 reports. The full-texts of the remaining six reports were read. Only four studies met the inclusion criteria and were included in this systematic review.

CONCLUSIONS

The most frequently reported failures in the available studies were as follows: fiber post debonding, loss of retention of single crowns, and marginal gaps. Less frequently, chippings and fractures were recorded in SCs. No studies about complications related to FDPs were found.

CLINICAL RELEVANCE

A correlation between the failure rates of fiber posts and the type of prosthetic restorations just like SCs and FDPs cannot be found to date. Further randomized controlled clinical studies are required to achieve evidence-based conclusions, particularly about the use of fiber posts with FDPs.

Crown vs. composite for post-retained restorations: A randomized clinical trial

OBJECTIVES

This randomized clinical trial compared the survival of composite resin restorations and metal-ceramic crowns on endodontically treated teeth that received a glass fiber post using 2 different cementation methods.

METHODS

Forty-seven patients (age 42.5 ± 11.5) with fifty-seven endodontically treated teeth with extensive coronal damage but always with one intact surface were randomly allocated according to the type of coronal restoration: metal-ceramic crown or composite resin. In case of crown restoration, a core buildup was performed with microhybrid composite resin. The dentin bonding agent and composite resin used were the same for both direct and indirect restorations. Descriptive analysis was performed using FDI clinical criteria and survival of restorations/teeth analyzed using Kaplan-Meier statistics and log-rank tests.

RESULTS

57 restorations (30 composite resin and 27 crowns) were made in 47 patients. The recall rate was 100% and follow up time ranged between 1 and 5 years. One tooth was extracted 11 months post-restoration due to root fracture (composite group). Eight composite restorations and one crown had reparable failures, all due to secondary caries or restoration fracture. The overall annual failure rate (AFR) was 0.92% after 50 months for success of the restorations, with 1.83% for the composite group and 0.26% for the metal-ceramic crown group. The log-rank test showed no difference for survival according to the type of restoration (p=0.344). However, for success rates, metal-ceramic crowns demonstrated better performance (p=0.022).

CONCLUSIONS

Indirect restorations provided higher acceptable clinical performance and lower need for re-intervention, but both types of restorations presented good survival rates. (NCT01461239).

CLINICAL SIGNIFICANCE

When endodontically treated teeth with at least one intact surface must be restored, composite resin restorations and metal-ceramic crows are acceptable alternatives to achieve good survival and success rates.

Ferrule Effect

The aim of this study was to systematically review the literature for laboratory and clinical studies to evaluate the effect of ferrule in restored endodontically treated teeth. The search was conducted in 2 databases (PubMed, Scopus) with no publication year/language limits. From 1,872 potentially eligible studies, 124 studies were selected for full-text analysis, and 37 were included for review, with 32 of those considered in the meta-analysis and 5 considered in the survival analysis. Two reviewers independently selected the studies, extracted the data, and assessed the risk of bias. For laboratory studies, a meta-analysis was performed for the comparison of the fracture resistance of teeth with and without ferrule, and 3 subgroup analyses were conducted for ferrule height, post type, and type of tooth. For clinical studies, the Kaplan-Meier method was used to determine the survival of restorations, with log-rank test used to identify differences between groups ( α = 5%). Teeth without ferrule had a lower fracture resistance ( P < 0.00001), and the higher the height of ferrule, the greater the fracture resistance was, irrespective of the type of post ( P < .000001). Teeth with ferrule had higher clinical longevity ( P = 0.002); however, the presence of a ferrule was related to higher survival only for premolars ( P = 0.05). In conclusion, the presence of a ferrule is responsible for an improvement in the fracture resistance of the restoration in laboratory studies. Yet, other clinical factors besides the ferrule may be associated with survival in molars and anterior teeth and need to be further investigated.

Knowledge Transfer Statement: The results of this study can be used by clinicians when deciding which approach to use when planning the restoration of endodontically treated teeth with and without ferrule. Ferrule may lead to higher tooth/restoration survival, while tooth location may influence therapeutic decisions.