A practice-based study on the survival of restored endodontically treated teeth

Principles guiding the restoration of the root-filled tooth

Endodontic treatment is usually required because of significant coronal disease or traumatic tissue loss. The restoration of the subsequently endodontically treated tooth is also complicated by the reduction in its structural strength consequent to accessing the pulp chamber and the removal of radicular dentine during root canal instrumentation, alongside some alteration of dentinal properties during disinfection by chemical agents, prior to obturation. A loss of proprioceptive feedback, which may lead to increased loading, can place further stress on the already very compromised structure. This article considers the principles of restoring endodontically treated teeth: assessing restorability, providing a coronal seal to prevent reinfection, and gaining retention for a core where necessary, to restore aesthetics and function. Consideration is given to the patient and material factors that influence the decision to restore the treated tooth using direct or indirect restorations. Specific attention is given to anterior or posterior teeth and the various materials which may be used in their overall restoration with their associated, probable, longevity.

Changes in the Difficulty of Endodontic Cases Treated by Undergraduate Students at a University Clinic Between 1971 and 2019

OBJECTIVE

This study aimed to assess the proportions of complicated endodontic cases treated by undergraduate dental students in a University clinic now and in the past.

MATERIAL AND METHODS

Data were obtained from the electronic records and previous publications from the Faculty of Dentistry, University of Oslo, Norway. The operators were dental undergraduate students in their final 2 years of training. Proportions of tooth types, diagnosis, and retreatments were studied.

RESULTS

The amount of endodontically treated molars increased from 18% in 1971% to 44% in 2019. The number of teeth with preoperative apical periodontitis increased from 31% to 46%, and retreatments from 9% to 15%. The changes were highly significant, with the greatest change occurring from 1984 to 2009.

CONCLUSION

Undergraduate students are exposed to more complicated teeth now than 50 years ago.

Clinical behavior and survival of endodontically treated teeth with or without post placement: a systematic review and meta-analysis

PURPOSE

Non-vital teeth usually exhibit substantial loss of coronal and radicular tooth structure, and use of posts after root canal treatment is controversial. This review examined whether placement of posts influences clinical behavior and survival probability of endodontically treated teeth (ETT).

METHODS

An electronic search, without time restrictions, for publications written in English was undertaken in PubMed, Scopus, and Web of Science. Terms related to four main components (endodontically treated teeth, fixed prosthesis, post restoration, and survival rate) were used for the database search strategies.

RESULTS

57 studies met the inclusion criteria and were included in the qualitative analysis. Of the publications chosen for qualitative analysis, 17 clinical studies (11 prospective and 6 retrospective studies) were found to be suitable for quantitative analysis. These studies included 7,278 patients (7,330 ETT), with a mean age ± standard deviation (SD) of 45.46 ± 12.1 years. There was a statistically significant difference in survival rate between ETT with or without posts (P < 0.001).

CONCLUSION

As compared with teeth with no posts, post placement on ETT may improve clinical performance and survival probability of endodontically treated teeth.

The tooth survival of non-surgical root-filled posterior teeth and the associated prognostic tooth-related factors: A systematic review and meta-analysis

BACKGROUND

Analysis of the survival of root-filled posterior teeth and the associated prognostic tooth-related factors will enable clinicians to predict the outcome of root canal treatment.

OBJECTIVES

To investigate (i) the survival of root-filled posterior teeth and (ii) the tooth-related factors that may affect their survival.

METHODS

Randomized controlled trials, comparative studies and observational studies assessing survival rates of root-filled posterior teeth with a minimum 4-year follow-up period were identified through an electronic search of the following databases up to January 2023: The Cochrane Central Register of Controlled Trials, Medline via PubMed, the Cochrane Database of Systematic Reviews, Embase, Web of Science and NIHR centre for reviews and dissemination. Two reviewers (SP and ML) independently selected the final studies based on pre-defined inclusion criteria. The Newcastle Ottawa Scale and the Cochrane Risk of Bias Tool for Randomized Trials were used to assess the risk of bias. Pooled weighted survival rates were analysed using a random effects meta-analysis model using DerSimonean and Laird methods. Descriptive analysis of studies describing any prognostic tooth-related factors was conducted.

RESULTS

Of the 72 studies identified, data from 20 studies were included in the survival meta-analysis, and data from 13 of these studies were included in the descriptive analysis of tooth-related factors; 12 studies were retrospective, 7 were prospective, and one was a randomized control trial. The pooled survival rates at 4-7 years and 8-20 years of root-filled posterior teeth regardless of tooth type was 91% (95% CI, 0.85; 0.95) and 87% (95% CI, 0.77; 0.93), respectively. The prognostic tooth-related factors mentioned in the included studies were (i) remaining coronal tooth structure, (ii) ferrule, (iii) crown-to-root ratio (iv) tooth type and location (v) periodontal disease (vi) proximal contacts and (vii) cracks.

CONCLUSIONS

The meta-analysis suggests that root canal treatment has a high medium to long term survival outcome. The narrative summary identified 7 factors that affect tooth survival. However, there is a paucity of evidence, and more research is needed in this area.

REGISTRATION

PROSPERO Registration: CRD42021227213.

Direct Versus Indirect Treatment Options of Endodontically Treated Posterior Teeth: A Narrative Review

One of the controversial topics in dentistry is restoring endodontically treated posterior teeth. Most posterior teeth that undergo endodontic treatment are subjected to a high rate of fracture due to excessive amount of loss of tooth structure. The aim of this review is to evaluate and compare the restorative and prosthetic treatment options to provide clinical recommendations for restoring endodontically treated posterior teeth. Both Medline on PubMed and Google Scholar were utilized for the search. The terms on our keyword list were "crown," "onlay," "endo-crown," "amalgam," and "composite," with the time frame from 1977 to 2024. We also examined the reference lists of potentially relevant papers for any recent review articles. Our analysis examined review articles found through computerized searches, along with relevant citations from the bibliographies of those studies. This review will focus on the dental restorative options and the amount of remaining tooth structure in determining the final restoration of an endodontically treated posterior tooth. This narrative review addresses different treatment options for endodontically treated posterior teeth based on the amount of remaining tooth structure. In addition, it compares the survival rate and the limitations among direct and indirect restorations.

Further Interventions after Root Canal Treatment Are Most Common in Molars and Teeth Restored with Direct Restorations: A 10-11-Year Follow-Up of the Adult Swedish Population

INTRODUCTION

The aims were to investigate 1) the frequency of nonsurgical retreatment, root-end surgery, extraction, and further restorative treatment during a follow-up of 10-11 years after root filling and compare the frequencies according to tooth group and type of coronal restoration and 2) the timing of nonsurgical retreatment, root-end surgery, and extraction.

METHODS

Data were collected from the Swedish Social Insurance Agency's register. A search for treatment codes identified teeth root filled in 2009 and the type of coronal restoration (direct, indirect, and unspecified) registered within 6 months of root filling. The root-filled teeth were followed 10-11 years, and further interventions were recorded. Descriptive statistics and chi-square tests were used for statistical analysis.

RESULTS

In 2009, root fillings were registered for 215,611 individuals/teeth. Nonsurgical retreatment, root-end surgery, and extraction were undertaken in 3.5%, 1.4%, and 20% teeth, respectively. The frequency of further interventions varied with respect to tooth group and type of coronal restoration, but only slightly for endodontic retreatments. Further interventions, except for root-end surgery, were registered more often for molars and directly restored teeth (P < .001). The majority of endodontic retreatments were undertaken within 4 years, while extractions were evenly distributed over 10-11 years.

CONCLUSIONS

The frequency numbers of nonsurgical retreatment and root-end surgery were low, despite 1 in 5 root-filled teeth registered as extracted. Further interventions were most common in molars and directly restored teeth. Endodontic retreatments were performed more often during the first 4 years.

General dental practitioners' fees for root canal treatment, coronal restoration and follow-on treatment in the adult population in Sweden: A 10-year follow-up of data from the Swedish Dental Register

OBJECTIVES

To analyze the accumulated fees connected with root filling, permanent coronal restoration and follow-on treatment charged by Swedish dentists over a 10-11-year follow-up period. Furthermore, analyzing these fees with reference to the type of restoration, tooth group, and the root-filled teeth which survived compared to those requiring extraction.

MATERIAL AND METHODS

In 2009, the data register of the Swedish Social Insurance Agency recorded a total of 215,611 teeth as root-filled. The accumulated fees for each tooth encompassed the following interventions: initial root filling, coronal restorations, and follow-up treatments during the designated period. The outcomes were analyzed using descriptive and analytic statistics, including t tests and one-way analysis of variance. The fees are presented in Euros (€1 = SEK 8.94).

RESULTS

The total accumulated fees for root fillings amounted to 72 million Euros: the mean fee per root filled tooth was €333.6. The total mean fee over a 10-11-year period, comprising root canal treatment, coronal restorations, and any follow-up treatments, was €923.4. Root-filled teeth with indirect restorations presented a higher mean fee (€1 279.3) compared to those with direct restorations (€829.4) or those without specified restorations (€832.7; p < .001). Moreover, molars presented a significantly higher mean fee (€966.4) compared to premolars (€882.8) and anterior teeth (€891.3; p < .001). Lastly, the mean fee for extracted teeth was €1225.3, which was higher compared to those who survived the follow-up period (€848.0; p < .001).

CONCLUSIONS

Fees charged by general dental practitioners for root-filled teeth accumulate over time, probably due to the need for further treatment of the tooth. The total mean fee was significantly higher for molars and root-filled teeth with indirect restorations. However, an analysis of the total costs would require prospective clinical cost-effectiveness studies.

Success and complication rates of non-precious alloy telescopic crowns in a general dental practice

OBJECTIVES

This retrospective, single-center, practice-based cohort study aimed to analyze factors associated with the success of removable partial dentures retained by telescopic crowns (TRPD).

MATERIALS AND METHODS

TRPD which were placed in a single practice of a practice-based research network were analyzed. Data from 139 patients (age (SD): 66 (11) years; 66 female) with 174 TRPD including 488 non-precious alloy telescopic crowns (TC) between 2004 and 2016 were included. TC without any technical complication were considered as successful, and as survived, if they were still in function at the last check-up. Multilevel Cox proportional hazard models were used to evaluate the association between clinical factors and time until failure.

RESULTS

Within a mean follow-up period (SD) of 4.2 (3.3) years (min-max: 1 day-12 years), 372 (76%) TC (AFR5years,TC-level: 5.0%) as well as 136 (87%) TRPD (AFR5years,TRPD-level: 5.1%) ("worst-case scenario") and 150 (86%) TRPD (AFR5years,TRPD-level: 3.4%) ("best-case scenario") were considered as successful. The main failure types were recementation (n = 39), endodontic treatment (n = 36), and extraction (n = 35). TC in male patients showed 1.6 times higher risk for failure than in female patients (95%CI: 1.1-2.4; p = 0.023). TC on premolars showed 2.2 times higher risk for failure than on incisors (95%CI: 1.1-5.0; p = 0.023) and TC in dentures with ≤ 3TC showed 2.1 times higher risk for failure than TC in dentures with > 3TC (1.3-3.4; p = 0.042). Furthermore, TC on the most distal tooth in an arch showed 2.4 times higher risk for failure than TC on a more mesial tooth (1.5-3.8; p < 0.001).

CONCLUSION

For removable partial dentures retained by telescopic crowns, high success rates could be found after up to 12 years. Patient-level and tooth-level factors were significantly associated with failure.

CLINICAL RELEVANCE

For removable partial dentures retained by telescopic crowns, high success rates could be found after up to 12 years. Patient-level and tooth-level factors were significantly associated with failure.

Resin Composites in Posterior Teeth: Clinical Performance and Direct Restorative Techniques

Resin composites are the most versatile restorative materials used in dentistry and the first choice for restoring posterior teeth. This article reviews aspects that influence the clinical performance of composite restorations and addresses clinically relevant issues regarding different direct techniques for restoring posterior teeth that could be performed in varied clinical situations. The article discusses the results of long-term clinical trials with resin composites and the materials available in the market for posterior restorations. The importance of photoactivation is presented, including aspects concerning the improvement of the efficiency of light-curing procedures. With regard to the restorative techniques, the article addresses key elements and occlusion levels for restoring Class I and Class II cavities, in addition to restorative strategies using different shades/opacities of resin composites in incremental techniques, restorations using bulk-fill composites, and shade-matching composites.

Root Canal Treatment Survival Analysis in National Dental PBRN Practices

Few studies have examined the longevity of endodontically treated teeth in nonacademic clinical settings where most of the population receives its care. This study aimed to quantify the longevity of teeth treated endodontically in general dentistry practices and test the hypothesis that longevity significantly differed by the patient's age, gender, dental insurance, geographic region, and placement of a crown and/or other restoration soon after root canal treatment (RCT). This retrospective study used deidentified data of patients who underwent RCT of permanent teeth through October 2015 in 99 general dentistry practices in the National Dental Practice-Based Research Network (Network). The data set included 46,702 patients and 71,283 RCT permanent teeth. The Kaplan-Meier (product limit) estimator was performed to estimate survival rate after the first RCT performed on a specific tooth. The Cox proportional hazards model was done to account for patient- and tooth-specific covariates. The overall median survival time was 11.1 y; 26% of RCT teeth survived beyond 20 y. Tooth type, presence of dental insurance any time during dental care, placement of crown and/or receiving a filling soon after RCT, and Network region were significant predictors of survival time (P < 0.0001). Gender and age were not statistically significant predictors in univariable analysis, but in multivariable analyses, gender was significant after accounting for other variables. This study of Network practices geographically distributed across the United States observed shorter longevity of endodontically treated permanent teeth than in previous community-based studies. Also, having a crown placed following an RCT was associated with 5.3 y longer median survival time. Teeth that received a filling soon after the RCT before the crown was placed had a median survival time of 20.1 y compared to RCT teeth with only a crown (11.4 y), only a filling (11.2 y), or no filling and no crown (6.5 y).

The influence of indirect bonded restorations on clinical prognosis of endodontically treated teeth: A systematic review and meta-analysis

OBJECTIVE

The loss of the dental coronal portion following carious lesions or fractures leads to endodontic treatment with subsequent restoration to ensure correct anatomy and function. Recently, partial adhesive restorations have been widely proposed to increase the survival rate of endodontically treated teeth. The primary purpose of this review is to assess the failure rate of indirect partial adhesive restorations on endodontically treated teeth (ETT), considering the follow-up period.

METHODS

The indications reported in the PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analysis) were used to draft the present review. The study was constructed on PICO questions: population (patients who need indirect adhesive restorative treatment on endodontically treated teeth with onlay and overlay), intervention (onlay and overlay), control (patients with onlay and overlay on endodontically treated teeth) and outcome (failure rate and types of failure for onlay and overlay). The asked scientific question was: what are the failure rate and types of failure for adhesive indirect partial restorations on ETT?

RESULTS

The overall failure rate that emerges is 0.087 with a ratio of 121/1254, I² 80 % p-value< 0.001. Moreover, by meta-regression with covariates the follow-up period reports a coefficient of 0.013 with a P-value< 0.001. In conclusion, the indirect partial restorations on endodontically treated teeth displayed overall acceptable outcomes in terms of success from 2 to 4 years after their placement with only 4.32 % of failure. Failures increase after 7 years up to 12-30 years with failure rates of approximatively 10.65 % and 20.94 %. The analysis of the included articles reporting the causes of restorations failures showed that 15.51 % of cases were related to the loss of dental element.

SIGNIFICANCE

Besides the survival rates of indirect adhesive restorations on endodontically treated posterior teeth, it was highlighted that the majority of failures appeared restorable. Thus, partial restorations seemed able to prevent the ETT tooth loss.

Finite element and in vitro study on biomechanical behavior of endodontically treated premolars restored with direct or indirect composite restorations

Objectives of the study were to investigate biomechanical properties of severely compromised premolars restored with composite restorations using finite element analysis (FEA), and in vitro fracture resistance test. A 3-D model of an endodontically treated premolar was created in Solidworks. Different composite restorations were modelled (direct restoration-DR; endo-crown-EC; post, core, and crown-C) with two different supporting tissues: periodontal ligament/alveolar bone (B), and polymethyl methacrylate (PMMA). Models were two-point axially loaded occlusally (850 N). Von Mises stresses and strains were calculated. The same groups were further tested for static fracture resistance in vitro (n = 5, 6.0 mm-diameter ball indenter, vertical load). Fracture resistance data were statistically analyzed (p < 0.050). The highest stresses and strains in all FEA models were observed on occlusal and vestibular cervical surfaces, corresponding to fracture propagation demonstrated in vitro. C showed the lowest stress in dentin, while EC showed lower stresses and strains in crown cement. B models demonstrated larger high stress areas in the root than PMMA models. No significant differences in fracture resistance (N) were observed between groups (DR: 747.7 ± 164.0, EC: 867.3 ± 108.1, C: 866.9 ± 126.3; p = 0.307). More conservative restorations seem a feasible alternative for endodontically treated premolars to conventional post-core-crown.

Longevity of immediate rehabilitation with direct metal-wire reinforced composite fixed partial dentures

OBJECTIVES

This study aimed to analyze the longevity of direct metal-wire reinforced composite fixed partial dentures (MRC-FPD) and factors influencing their survival and success.

METHODS

Within one private practice 513 MRC-FPD were directly applied. The preparation of a proximal cavity in abutment teeth was not limited. MRC-FPD were reinforced by one to three metal-wires. At the last follow-up MRC-FPD were considered successful, if they were still in function without any need of therapy. MRC-FPD were considered as survived, if they were repaired or replaced. Multi-level Cox proportional hazard models were used to evaluate the association between clinical factors and time.

RESULTS

Mean follow-up period (range) was 59(2-249) months. Seventy-three bridges did not survive (cumulative survival rate(CSR):86%) and further 129 bridges had received a restorative follow-up treatment (CSR:61%). AFR was 2.2% for survival and 8.6% for success. In multivariate analysis MRC-FPD with> 1 wire showed a up to 2.3x higher failure rate than MRC-FPD with one wire(p ≤ 0.023). Dentist's experience in designing MRC-FDP (p ≤ 0.017), patient's caries risk (p ≤ 0.040) and bruxism (p = 0.033) significantly influenced the failure rate: the more experience, the lower caries risk and bruxism, the lower the failure rate.

SIGNIFICANCE

For directly prepared metal-wire reinforced composite bridges high survival and moderate success rates were observed. MRC-FPD might, thus, be an immediate, short- and medium-term solution for replacing missing teeth. However, several factors on the levels of practice (dentist's experience in designing MRC-FDP), patient (bruxism, caries risk) and restoration (number of wires) were identified as significant predictors for the failure rate. The study was registered in the German Clinical Trials Register (DRKS-ID: DRKS00021576).

Post-Fatigue Fracture and Marginal Behavior of Endodontically Treated Teeth: Partial Crown vs. Full Crown vs. Endocrown vs. Fiber-Reinforced Resin Composite

Objectives: To investigate in vitro post-fatigue fracture behavior of endodontically treated molars having been differently restored. Methods: A total of 120 extracted human molars were used. A total of 120 specimens in 14 test groups and one control group (n = 8) were root canal treated. After postendodontic sealing and build-up (AdheSE Universal, SDR), additional MOD preparations were cut. Postendodontic restorations were: Direct restorations (Tetric EvoCeram BulkFill bonded with AdheSE Universal and EverX Posterior/Essentia bonded with G-Premio Bond; as filling (F) or direct partial crown (DPC) after reducing the cusps 2 mm; indirect adhesive restorations (partial crown/PC vs. full crown/FC): e.max CAD, Celtra Duo, both luted with Variolink Esthetic; indirect zirconia restorations (partial crown/PC vs. full crown/FC), luted with RelyX Unicem 2; indirect non-bonded cast gold restorations (partial crown/PC vs. full crown/FC; Degunorm), luted with Ketac Cem. Before and after 300,000 thermocycles (5/55 °C) and 1.2 Mio. A total of 100 N load cycles, replicas were analyzed under a SEM for marginal quality in enamel and dentin (where applicable) and finally, specimens were loaded until fracture. Results: In direct groups, there was no difference between RC and FRC in fracture strength (p > 0.05); however, direct partial crowns showed higher post-fatigue fracture resistance. Regarding marginal quality, intracoronal FRC restorations exhibited more gap-free margins in enamel than RC. In the indirect groups, there was no significant difference between partial and full crowns in any of the adhesively luted ceramic groups regarding post-fatigue fracture resistance. Zirconia partial crowns exhibited significantly lower marginal quality in enamel. Indirect groups performed significantly better than direct groups in fracture resistance. Within the indirect restorations, both cast gold groups and zirconia full crowns exhibited the highest fracture resistance being superior to control teeth. Significances: Within the limits of this in vitro investigation, it can be concluded that any kind of indirect restoration with cusp replacement is suitable for ETT restoration when a certain cavity extension is exceeded. All indirect restorations, i.e., endocrowns, partial crowns, and full crowns showed a promising performance after in vitro fatigue-loading.

Clinical outcome of bonded partial indirect posterior restorations on vital and non-vital teeth: a systematic review and meta-analysis

OBJECTIVES

The survival rate of indirect partial adhesive restorations on vital versus endodontically treated teeth is still controversial. The hypothesis is that there may be a difference in the survival rate of partial adhesive restorations performed on non-vital teeth compared to vital teeth.

MATERIALS AND METHODS

This systematic review was conducted following the PRISMA guidelines. The considered clinical studies investigated the outcomes of adhesive inlays, onlays, and overlays conducted over the past 40 years, focusing on Kaplan-Meier survival curves to calculate the hazard ratio (primary objective) and the survival rate (secondary objective) between vital and non-vital teeth. The risk of bias was assessed using the Newcastle-Ottawa Scale. Studies included in the review were identified through bibliographic research on electronic databases ("PubMed," "Scopus," "Cochrane Central Register of Controlled Trial," and "Embase"). The K agreement between the two screening reviewers was evaluated.

RESULTS

A total of 55,793 records were identified on PubMed, Scopus, and other bibliographic sources, and after the application of the eligibility and inclusion criteria, eight articles were included for qualitative analysis and six for quantitative analysis. The meta-analysis of the primary and secondary outcomes demonstrated that hazard ratios (HR = 8.41, 95% CI: [4.50, 15.72]) and survival rates (OR = 3.24, 95% CI: [1.76, 5.82]) seemed more favorable for indirect partial adhesive restorations on vital teeth than for those on endodontically treated teeth.

CONCLUSIONS

Within the limits of this study, these findings suggest that the risk of failure of indirect partial adhesive restorations on endodontically treated teeth is higher than on vital teeth.

CLINICAL RELEVANCE

The use of partial adhesive restorations on vital and endodontically treated teeth showed different long-term clinical outcomes.

Stress Concentration of Endodontically Treated Molars Restored with Transfixed Glass Fiber Post: 3D-Finite Element Analysis

The loss of dental structure caused by endodontic treatment is responsible for a decrease in tooth resistance, which increases susceptibility to fracture. Therefore, it is important that minimally invasive treatments be performed to preserve the dental structure and increase the resistance to fracture of endodontically treated posterior teeth. To evaluate under axial loads, using the finite element method, the stress distribution in endodontically treated molars restored with both transfixed or vertical glass fiber posts (GFP) and resin composite. An endodontically treated molar 3D-model was analyzed using finite element analyses under four different conditions, class II resin composite (G1, control model), vertical glass fiber post (G2), transfixed glass fiber posts (G3) and vertical and transfixed glass fiber posts (G4). Ideal contacts were considered between restoration/resin composite and resin composite/tooth. An axial load (300 N) was applied to the occlusal surface. The resulting tensile stresses were calculated for the enamel and dentin tissue from five different viewports (occlusal, buccal, palatal, mesial and distal views). According to the stress maps, similar stress trends were observed, regardless of the glass fiber post treatment. In addition, for the G1 model (without GFP), a high-stress magnitude can be noticed in the proximal faces of enamel (7.7 to 14 MPa) and dentin (2.1 to 3.3 MPa) tissue. The use of transfixed glass fiber post is not indicated to reduce the stresses, under axial loads, in both enamel and dentin tissue in endodontically treated molar with a class II cavity.

Radiographic periapical healing associated with root-treated teeth accessed through existing crowns: a historical controlled cohort study

OBJECTIVES

The aim of this study was to determine the periapical healing rate and complications arising from non-surgical root canal treatment (NSRCT) conducted through the existing and retained restoration, compared to that conducted after removal of restoration (direct or indirect) with subsequent placement of a new crown.

MATERIALS AND METHODS

Two-hundred-and-forty-five teeth met the inclusion criteria and were followed up for 2 years. One-hundred-and-six teeth had NSRCT completed through existing cast restorations, and 57 and 82 had the existing crowns and direct restorations removed (respectively) and received a new crown after NSRCT. Periapical healing was assessed radiographically using strict (complete healing) and loose (complete and incomplete healing) criteria. Multivariable logistic regression models were used to investigate the effect of prior restoration removal on periapical healing following NSRCT, adjusting for potential confounding (p < 0.05).

RESULTS

There was no significant (p > 0.05) difference in the periapical healing rates amongst teeth accessed through existing crowns (72%, 90%) versus those where crowns (79%, 93%) or direct restorations (77%, 90%) were removed for NSRCT. The findings were adjusted for the significant influencing factor: size of pre-operative radiolucency (p < 0.05). Of the 109 teeth that were initially accessed through existing crowns, 9 (8%) displayed porcelain fracture or crown de-cementation.

CONCLUSION

Performing root canal treatment through an existing full coverage restoration did not compromise periapical healing and was associated with a low incidence of associated complications.

CLINICAL RELEVANCE

Crown removal before NSRCT is not mandatory for periapical healing but requires a judicious pre-assessment of current and future marginal and restorative integrity.

Long-Term Follow-Up of Nonsurgical Endodontic Treatments Performed by One Specialist: A Retrospective Cohort Study about Tooth Survival and Treatment Success

Background

The main aim of the retrospective cohort study was to evaluate tooth survival after the endodontic treatment over a period of more than 20 years. Moreover, success of the treatment and the correlation between baseline parameters and the outcomes were analyzed, and causes were recorded.

Materials and Methods

Clinical records (including radiographs) of subjects treated with endodontic procedures (both primary and secondary (nonsurgical retreatment)) were collected and analyzed, covering a period of up to 29 years. Type of the treatment, technique, adequacy of treatment performed, presence of baseline radiolucency, and symptoms at baseline were recorded. Moreover, failure (presence of radiolucency 2 years after treatment) and tooth extraction data and causes of them were recorded. Outcomes were explored by using survival analysis (Kaplan-Meier estimates and survival table analysis) and regression analysis (Cox regression).

Results

A total of 2,679 endodontically treated teeth were included in the analysis. After 20 years from the treatment, the cumulative survival rate for primary and secondary treatments was 84.10% (80.99%-87.21%) and 89.79% (86.68%-92.90%), respectively. No differences were found between primary and secondary treatments or with regard to the technique adopted. The presence of periapical radiolucency was correlated to higher odds of tooth extraction.

Conclusions

Despite the limitations of the study, we can assume that the proportion of retained endodontically treated teeth was significantly high over a long-term period.

Outcome of Root Canal Treatments Provided by Endodontic Postgraduate Students. A Retrospective Study

The aim of this study was to assess the preoperative, intraoperative, and postoperative factors that influenced complete periapical healing in teeth that underwent primary root canal treatment (RCT), in patients treated by postgraduate students in endodontics. Factors were retrieved and compared with the periapical status during the follow-up visit. Healing was considered as the absence of clinical and radiological symptoms. Variables significantly associated by the chi-squared test were included in a logistic regression model (LRM). Preoperative factors associated with healing were: American Society of Anesthesiology (ASA) status (p = 0.01); the absence of preoperative pain (p = 0.04); positive response to pulp tests; when the RCT cause was caries, pain, abscess, or sinus tract; probing depth <4 mm; the absence of mobility; absence or <4 mm periapical lesion (p < 0.01). In the LRM, the factors included were: absence or <4 mm periapical lesion; probing depths <4 mm; RCT caused by caries, pain, abscess, or sinus tract; the tooth was not a bridge abutment. Postoperative factors were: teeth with direct restoration; teeth that did not act as a support for a fixed prosthetic restoration; the favorable condition of the coronal restoration (p < 0.01). In the LRM, only the status of the coronal restoration was included. Preoperative conditions and the adequate fit of the coronal restoration influenced the outcome of RCT.

A prospective study on the effect of coronal tooth structure loss on the 4-year clinical survival of root canal retreated teeth and retrospective validation of the Dental Practicality Index

AIM

First, to examine the impact of the residual volume of coronal tooth structure in posterior teeth measured with an intra-oral scanner on the 4-year clinical survival of root canal retreated teeth. Secondly, to assess retrospectively the effectiveness of the Dental Practicality Index (DPI) in predicting the survival of root canal retreated teeth.

METHODOLOGY

A total of 156 posterior root canal treated teeth (140 patients) had baseline periapical radiographs (PA) and cone-beam computed tomography (CBCT) scans taken prior to root canal retreatment. These teeth were followed up with a clinical examination at 1, 2, 3 and 4 years (T12, T24, T36 and T48) with periapical radiographs and CBCT images taken at T12, and PA taken at T24, T36 and T48 where appropriate. Root canal retreated teeth were dichotomized into 'survived' versus 'extracted'. Fisher's exact test was used to determine the association between the volume of remaining coronal tooth structure and the 4-year tooth survival. The Dental Practicality Index for each tooth was established using the preoperative clinical and radiographical data. Fisher's exact test was used to establish a relationship between categorical variables, the total score of DPI vs tooth outcome.

RESULTS

The percentage of extractions associated with teeth with <29.5% remaining coronal tooth structure was 3 times higher (12.5%) compared to that of teeth with a residual tooth structure > 29.5% (3.5%), but with no significant difference (P = 0.073). There was a significant correlation between the outcome of root canal retreatments at 1 year, assessed by both PA and CBCT, and the 4-year survival (Fisher's exact test, P = 0.007 and P = 0.001, respectively). Teeth with DPI scores ≥ 6 were more likely to be extracted than teeth with DPI score < 6 (18.8% vs. 3.9%) (Fisher's exact test, P = 0.045).

CONCLUSION

Teeth with <30% of remaining tooth structure were associated with a survival rate above 80% and teeth with more than 30% of residual tooth structure survived in more than 94% of the cases. The radiographic outcome of root canal treatment can also help to predict tooth survival with teeth having an unfavourable outcome at 1 year more likely to be extracted within 4 years of completion of treatment. The DPI score can potentially be used to identify teeth with failed root canal treatment, which are likely to be extracted following retreatment and cuspal coverage.

Which materials would account for a better mechanical behavior for direct endocrown restorations?

PURPOSE

To investigate the mechanical performance and fracture behavior of endocrown restorations prepared using different composite materials and following a direct technique.

METHODS

Sound molars were cut at 2 mm above the cementoenamel junction, endodontically treated, and allocated according to the type of restoration (n = 7): without post (endocrowns) or with post (post-retained restorations). Endocrowns were fabricated with conventional composite (Filtek Z350); bulk fill composite (Filtek Bulk Fill); conventional composite modeled using resin adhesives (SBMP: Scotchbond Multipurpose Adhesive; or SBU: Scotchbond Universal Adhesive); and lithium disilicate ceramic (E.max; Positive control). The post-retained restorations were fabricated with glass-fiber post combined with conventional or bulk fill composites. All restorations were bonded following an etch-and-rise adhesive approach or self-adhesive resin cement. The teeth were submitted to fatigue (Byocycle) and compression (EMIC DL500) testing at a crosshead speed of 1 mm/min. Data were analyzed with ANOVA and Tukey (p < 0.05) and Weibull analysis was carried out in order to evaluate the reliability of restorations.

RESULTS

The bulk-fill-based endocrown showed a stronger performance than the control. The presence of SBMP or the use of bulk-fill composite resulted in the occurrence of less aggressive fractures than the other restorative systems. Endocrowns bonded directly to the tooth seemed to produce similar fracture strength properties as compared to endocrowns bonded using self-adhesive resin cementation. The bulk-fill-based endocrown showed the greatest reliability of study.

CONCLUSION

Resin-based restorative materials seem to be interesting alternative options to fabricate large dental restorations in lieu of the more traditionally used glass ceramics or root canal post systems.

Survival Rates of Endodontically Treated Teeth After Placement of Definitive Coronal Restoration: 8-Year Retrospective Study

Introduction

Preservation of endodontically treated teeth (ETT) depends upon several patient-related and operator-related factors. The objectives of this study were to assess the effects of different types of coronal restoration and delayed placement on ETT survival.

Methods

Data on dates of root canal treatment (RCT), restoration type, and extraction time of tooth, when applicable, were analyzed for all patients who underwent RCT from 2010 to 2018 at our institution.

Inclusion Criteria

Root canal-treated teeth with complete preoperative and postoperative radiographs; ETT that were restorable and received final permanent coronal restorations; no periodontal disease or crack detected during RCT; and ETT with acceptable RCT quality.

Exclusion Criteria

Patients who did not attend for follow-up, those had incomplete information available about the coronal restoration, and those with periodontally compromised teeth were excluded. ETT that involved any procedural error were also excluded. The teeth were categorized according to whether they underwent definitive coronal restoration 0–14 days, 15–59 days, or 60+ days after RCT. The statistical analysis was performed using SPSS version 25 (IBM Corp., Armonk, NY). The rate of survival of ETT of 8 years was estimated, and the differences between groups were determined after applying Kaplan–Meier statistics and log-rank tests. A multivariate Cox regression test and Wilcoxon (Gehan) statistics were computed to analyze the influence of different variables. A P-value <0.05 was considered as statistically significant.

Results

The type of restoration, opposing dentition, presence of a post, and dentistry training (year 4 or 5 students) showed significant effects on the survival of ETT (P ≤ 0.000). ETT which received crowns was 2.05 times more likely to need extraction than those in which a composite buildup was performed (hazard ratio [HR] 2.05; confidence interval [CI] 1.84–2.29; P ≤ 0.000). All composite buildups were performed within 14 days of completion of RCT. There was a significant correlation between the time of placement of the final coronal restoration and ETT survival (P ≤ 0.000). Extraction of ETT was 25% more likely (HR 0.25; CI 0.231–0.277) when the final coronal restoration was placed 15–59 days after completion of RCT and 73% more likely (HR 0.73; CI 0.655–0.814) when placed after 60 days than when placed at 0–14 days.

Conclusion

Timely placement of the final coronal restoration is found to be the most critical factor affecting the long-term survival of teeth after RCT.

A retrospective assessment of different endodontic treatment protocols

Background

The aim of this study was to assess the clinical impact of non-surgical root canal treatments (NSRCT) performed with different treatment protocols on the probability of tooth survival without untoward events and to identify predictors influencing the outcome.

Methods

During the period from July 1999 to October 2016, 5,858 patients were identified in which 9,967 NSRCTs were performed. The treatments were followed up and divided into three groups. In Group 1 root canal treatment was performed with hand instruments, in Group 2 with multiple file rotary instruments and passive ultrasonic irrigation (PUI), and Group 3 was treated with Reciproc instruments and PUI. Untoward events were defined as orthograde retreatment, apicoectomy or extraction of the tooth after initial treatment. Weibull regression was used to analyse the data.

Results

A total of 9,938 cases could be included into the analyses. The results showed 5-years predicted survival rates without untoward events of 73.9% (95% CI [71.7%–76.1%]), 75.1% (95% CI [71.7%–78.0%]) and 78.4% (95% CI [75.1%–81.4%]) for study group 1 (N = 5,580), 2 (N = 1,700) and 3 (N = 2,658), respectively. The differences between Group 1 and 3 were statistically significant (p < 0.006). Higher age of the patient (per year increase) and number of earlier NSRCTs (per unit increase) reduce the survival without untoward events statistically significant (both p < 0.02), while treatment of premolars had a statistically significant lower hazard ratio [0.89 (95% CI [0.79–0.99]; p = 0.030)] compared to treatment of molars and anterior teeth. A higher number of supportive periodontal treatments (per unit increase) improved tooth survival without untoward events highly significant (p < 0.0001).

Discussion

More recent endodontic treatment protocols involving reciprocating instruments and PUI appear to be associated with higher tooth survival rates without untoward events compared to hand instruments.

Effect of Repairing Endodontic Access Cavities on Survival of Single Crowns and Retainer Restorations

INTRODUCTION

This retrospective study aimed to analyze the effect of repairing endodontic access cavities with composite on the survival of single crowns and retainer restorations of fixed or removable dental prostheses.

METHODS

Dental records of patients attending a university dental clinic were retrospectively screened for single crowns and retainer restorations receiving endodontic treatment after crown placement. Survival (no further intervention) and failure (removal, loss or replacement of crown, replacement of access restoration, or recementation of restoration) of crowns and retainers with repaired endodontic access cavities were recorded. The mean annual failure rates were calculated, and the effect of individual-, tooth-, and restoration-related variables on survival was assessed by univariate log-rank tests and multivariate Cox regression analyses with shared frailty (P < .05).

RESULTS

One hundred eighty repaired crowns/retainers placed in 151 patients were included (4.5 ± 3.3 years follow-up). Survival after 2, 5, 7, and 10 years amounted to 82.7%, 71.5%, 67.3%, and 48.8% (mean annual failure rate = 9.0%, 6.5%, 5.5%, and 6.9%), respectively. Although tooth type, kind of restoration, endodontic irrigant, repair conditioning methods, and kind of composite affected survival in the univariate regression analyses, only the kind of restoration (single crown vs retainer restoration) remained significant in the multivariate Cox regression model.

CONCLUSIONS

Repairing endodontic access cavities with composite increases the longevity of single crowns and retainer restorations.

Do endodontic retreatment techniques influence the fracture strength of endodontically treated teeth? A systematic review and meta-analysis

One of the major concerns about endodontically retreated teeth (ERT) is undoubtedly its loss of remnant structure, which could lead to consequently greater fracture risk. Therefore, the objective of this systematic review is to assess the influence of endodontic retreatment on the fracture strength of the dental tooth remnant. In vitro studies assessing the influence of mechanical retreatment on the mechanical properties (static or under fatigue) of restored teeth were searched in PubMed and SCOPUS databases. Three independent reviewers screened titles/abstracts of articles and the full-text of potentially eligible studies. The risk of bias was independently assessed by one researcher and verified by another two. Comparison between the mean load to fracture of teeth after endodontic treatment and after endodontic retreatment were estimated using pairwise random effects meta-analysis to calculate pooled mean differences. Three studies were included for the systematic review and 2 for the meta-analysis. The pooled effect indicated a statistical difference (Mean difference: -121.03 95%CI: -183.02, -59.05) between conditions favoring the endodontically treated teeth. However, the low number of studies combined with their heterogeneity made it difficult to prove such phenomenon. ERT might present lower fracture strength than endodontically treated teeth. However, more coherent laboratory tests may provide better evidence and quantitative parameters on how much reliability can be attributed to an endodontic retreatment, in addition to which technique can provide more predictable results in this conservative approach.

Influence of restorative procedures on endodontically treated premolars: Finite element analysis of a CT-scan based three-dimensional model

An endodontically treated tooth with mesial-occlusal-distal (MOD) cavity is often restored with composite resin. Palatal and buccal cusp reduction (MODP, MODPB), and/or fiber-reinforced composite posts (P), are used in an attempt to improve the longevity of the restoration. The aim of this study was to determine the effects of these procedures on von Mises stress values and distribution in dental tissues and restorative materials using finite element analysis. Based on CT scans of an extracted second upper premolar, six 3D endodontically treated tooth models (MOD, MODP, MODPB, MOD+P, MODP+P, MODPB+P) were created. Each model was subjected to a summary force of 150 N on the occlusal surface simulating the normal biting pattern and maximal von Mises stresses were calculated. MODP seems to reduce von Mises stress values in dental tissues and P seems to transfer some of the stresses from dental tissues to the composite filling.

A practice based longevity study on single-unit crowns

OBJECTIVES

This retrospective longitudinal study aimed to assess the longevity of single unit crowns placed by several dentists and to investigate risk factors associated with crown failures.

METHODS

From patient files, longevity of 3404 full crown restorations placed in 1557 patients by 8 Dutch dentists between 1996 and 2011 were analyzed. Annual failure rates (AFRs) were calculated and variables associated with failure (success and survival of crowns) were assessed by multivariate Cox-regressions analysis with shared frailty for patients.

RESULTS

Most of crowns were PFM (63.8%) placed in molars (58.1%) and non endodontically treated teeth (65.4%). The observation time of restorations varied from 3 weeks to 11 years with a mean of 7 years, resulting in a mean AFR at 11 years of 2.1% and 0.7% for success and survival of crowns, respectively. Among dentists a relevant variation for type of interventions was observed with AFR varying between 1.2% and 3.5%. The most significant risk factor for failure of crowns was the presence of an endodontic treatment, resulting in Hazard ratios of 1.31 for success [95%CI 1.07-1.61] and 1.89 [95%CI 1.35-2.65] for survival of crowns. Tooth type, tooth position (jaw) and gender showed also a significant influence on success of crowns. For survival, increase in patients' age results in a higher risk for failure.

CONCLUSIONS

Overall, crowns placed by a selected group of dentist showed a good to acceptable success and survival rates, mainly dependent from the practice. The presence of an endodontically treated tooth was a significant risk factor leading to more failures.

Endodontic decision making for asymptomatic root-filled teeth with apical periodontitis - A radiographic survey

The aim of the study was to compare decision making for asymptomatic root-filled teeth among dentists with differing educational backgrounds. Case scenarios based on 14 radiographs were created and 150 participants were asked to choose from five alternative treatment decisions and to state the rationale. Demographic data of the participants were recorded. Frequency distribution and cross-tabulation were performed; chi square testing was used for comparisons and logistic regression was performed to detect significant differences. The overall response rate was 87.3%. The practitioners chose intervention predominantly with non-surgical retreatment a common choice. Poor technical quality was a driving factor, while the existing poor coronal restoration and the need for a crown were generally not taken into account by general dentists. Speciality and experience were significant factors. Practitioners were more inclined to retain rather than extract teeth. It is concluded that clear guidelines listing factors to consider for intervention are required.

Survival rates against fracture of endodontically treated posterior teeth restored with full-coverage crowns or resin composite restorations: a systematic review

This systematic review aims to summarize the current clinical studies that investigated survival rates against fracture of endodontically treated posterior teeth restored with crowns or resin composite restorations. Literature search were performed using keywords. Publications from 1980 to 2016 were searched in PubMed, ScienceDirect, Web of Science, MEDLINE, and SCOPUS. Included studies were selected based on inclusion and exclusion criteria. Three clinical studies were included: 1 randomized controlled trial and 1 prospective and 1 retrospective cohort studies. Pooled survival rates ranged from 94%–100% and 91.9%–100% for crowns and resin composite, respectively. The majority of teeth had no more than 3 surface loss of tooth structure. The studies included were heterogeneous, and were not appropriate for further meta-analysis. Current evidence suggested that the survival rates against the fracture of endodontically treated posterior teeth restored with crowns or resin composites were not significantly different in the teeth with minimum to moderate loss of tooth structure.

Further Treatments of Root-filled Teeth in the Swedish Adult Population: A Comparison of Teeth Restored with Direct and Indirect Coronal Restorations

INTRODUCTION

The aim of this study was to evaluate the frequencies of nonsurgical retreatment, root-end surgery, extraction, and further restoration of root-filled teeth in Sweden in 2009 during a follow-up period of 5 years and to compare the outcomes in teeth restored with direct or indirect restorations.

METHODS

Data from the Swedish Social Insurance Agency were analyzed, and the frequencies of nonsurgical retreatment, root-end surgery, extractions, and further restoration were calculated for all teeth registered as root filled during 2009. Chi-square tests were applied to detect any significant differences in the frequency of further treatment in teeth registered as restored with either a direct or an indirect restoration within 6 months of root filling.

RESULTS

Of the 248,299 teeth reported root filled in Sweden in 2009, nonsurgical retreatment was registered in 2.2%, root-end surgery in 1.0%, and extractions in 9.2% during the follow-up period. Of the teeth restored with a direct restoration within 6 months after the root filling, 30.3% were registered as having undergone at least 1 further direct restoration; the corresponding percentage of teeth with indirect restorations was 6.4%. A statistically significant difference in the frequency of nonsurgical retreatment, extraction, and further restoration was found; teeth restored with an indirect restoration within 6 months of root filling had fewer of these treatments than those restored by direct restoration.

CONCLUSIONS

Low frequencies of nonsurgical retreatment and root-end surgery were reported 5 years after root filling, whereas extraction was more common. Fewer additional treatment procedures were registered for teeth with indirect restorations than for those with direct restorations.

Prognostic factors of single-visit endodontic and restorative treatment under general anaesthesia for special needs patients

The aim of this study was to evaluate the longevity of teeth with single-visit endodontic and restorative treatment under general anaesthesia (GA) for special needs patients and to investigate factors associated with survival and success. Data were collected from 381 teeth in 203 patients [mean (s.d.) age = 27·0 (14·1)]. All endodontic and restorative procedures were performed during a single GA session except for cementation of crowns in the cases requiring crown restoration (38%). A total of 267 teeth (70·6%) were followed-up for 6-81 months [mean (s.d.): 32·7 (20·0)]. Patients and teeth with and without follow-up were compared. Kaplan-Meier analysis with generalised Wilcoxon test was used to compare the mean survival and success period. Cox proportion hazard regression model was applied for multivariate analysis. At the end of the observation period, 10 teeth had a crown fracture (5-year survival rate = 89·8%), and an additional 10 teeth had primary or secondary caries (5-year success rate = 86·4%). Risk factors associated with survival were age (>40), non-parental caregiver, cooperation level and periodontal disease. A soft diet was an additional risk factor against the success of teeth. Single-visit endodontic and restorative treatment under GA showed favourable outcomes, suggesting a promising treatment option for special needs patients. Patient- and dental-specific circumstances need to be carefully considered to enhance the longevity of reconstructed teeth.

Effects of fiber-glass-reinforced composite restorations on fracture resistance and failure mode of endodontically treated molars

OBJECTIVES

The study evaluated the fracture resistance and fracture patterns of endodontically treated mandibular first molars restored with glass-fiber-reinforced direct composite restorations.

METHODS

In total, 60 extracted intact first molars were treated endodontically; a mesio-occluso-distal (MOD) cavity was prepared and specimens were then divided into six groups: sound teeth (G1), no restoration (G2), direct composite restoration (G3), fiber-post-supported direct composite restoration (G4), direct composite reinforced with horizontal mesio-distal glass-fibers (G5), and buccal-palatal glass-fibers (G6). Specimens were subjected to 5000 thermocycles and 20,000 cycles of 45° oblique loading force at 1.3Hz and 50N; they were then loaded until fracture. The maximum fracture loads were recorded in Newtons (N) and data were analyzed with one-way ANOVA and post-hoc Tukey tests (p<0.05). Fractured specimens were analyzed with a scanning electron microscope (SEM).

RESULTS

The mean static loads (in Newtons) were: G1, 831.83; G2, 282.86; G3, 364.18; G4, 502.93; G5, 499.26; and G6, 582.22. Fracture resistance did not differ among G4, G5, and G6, but was significantly higher than G3 (p=0.001). All specimens fractured in a catastrophic way. In G6, glass fibers inducted a partial deflection of the fracture, although they were not able to stop crack propagation.

CONCLUSIONS

For the direct restoration of endodontically treated molars, reinforcement of composite resins with glass-fibers or fiber posts can enhance fracture resistance. The SEM analysis showed a low ability of horizontal glass-fibers to deviate the fracture, but this effect was not sufficient to lead to more favorable fracture patterns above the cement-enamel junction (CEJ).

CLINICAL SIGNIFICANCE

The fracture resistance of endodontically treated molars restored with direct composite restorations seems to be increased by reinforcement with fibers, even if it is insufficient to restore sound molar fracture resistance and cannot avoid vertical fractures.

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.

Survival of Restored Endodontically Treated Teeth in Relation to Periodontal Status

Abstract The aim of the present study was to investigate the success and survival of restored endodontically treated teeth (ETT) in a general practice environment related to periodontal parameters. Data from 360 restored ETT treated between 2000 and 2011 were collected. Dates of interventions like restorations, repairs, replacements and extractions were recorded. Additionally, general information about patients and dentitions as well as periodontal status was recorded. Success was analyzed using Kaplan-Meier statistics and a multivariate Cox regression analysis was performed to assess variables influencing success and survival. After a mean observation time of 4.34 years (range 0.6 - 11.6 years), 19 teeth were extracted and 27 restorations needed repair or replacement. According to the Cox regression, increasing maximum pocket depth of the tooth resulted in a higher risk for failure (p=0.012). In conclusion, periodontal pocket depth was found to be a significant factor in the survival of restored ETT.

Stability of endodontically treated teeth with differently invasive restorations: Adhesive vs. non-adhesive cusp stabilization

OBJECTIVES

Aim of the present study was to evaluate fracture strength of endodontically treated molars with different preparations/restorations after thermomechanical loading in vitro.

METHODS

264 extracted human third molars were used. Beside the control group, 256 teeth in 32 test groups (n=8) received root canal treatment (MTwo #40/.6) and root canal obturation with AH Plus and Guttapercha. After postendodontic sealing and build-up (Syntac, SDR), specimens were additionally prepared MO or MOD. Postendodontic restorations were: Direct restorations (Tetric EvoCeram Bulk Fill bonded with Syntac; as filling or direct partial crown (PC) after reducing the cusps 3mm; amalgam as filling or direct pin-retained partial crown (PC)), vs. indirect adhesive restorations (I: Inlay vs. PC; IPS Empress I/PC; Celtra Duo I/PC; e.max CAD I/PC; Lava Ultimate I/PC; Enamic I/PC - all inserted with Syntac/Variolink) vs. cemented cast gold I/PC. After 300,000 thermocycles (5/55°C) and 1.2 Mio. 100N load cycles, specimens were loaded until fracture.

RESULTS

Whereas IPS Empress showed no difference between I and PC (p>0.05), in all other groups PC were significantly more stable than fillings/inlays (p<0.05), this effect was more pronounced after MOD preparations. Cast gold PC exhibited the highest fracture strengths (p<0.05), inlays the lowest (p<0.05). IPS Empress was generally inferior to the other bonded materials under investigation (p<0.05) which as PC almost reached the level of control specimens. Amalgam fillings showed the worst outcome (p<0.05).

SIGNIFICANCES

Less invasive preparation designs were not beneficial for the stability of postendodontic restorations. Except for IPS Empress, PC were generally more successful in restabilization of weakened cusps after endodontic treatment and preparation. Cast gold PC remain the ultimate stabilization tool for ETT in terms of fracture resistance.

Twenty-year follow-up of root filled teeth in a Swedish population receiving high-cost dental care

AIM

To study the 20-year survival rate and periapical status of root filled teeth in a Swedish population requiring high-cost dental care and to identify factors related to survival and normal periapical status at follow-up.

METHODOLOGY

The study population comprised 104 patients selected from four local health insurance districts with treatment plans including radiographs submitted for approval for reimbursement from the Swedish National Dental Insurance in 1977. In 1998, a clinical and radiographic follow-up examination was conducted, to register the status of 449 teeth identified as root filled at baseline. Differences in tooth survival and periapical status at follow-up, with reference to periapical status and quality of root filling at baseline, were analysed by chi-square tests. Multiple regression analysis was used to describe tooth survival and normal periapical status at follow-up, with the explanatory baseline variables: tooth type, type of restoration, type of post, quality of root filling, periapical status, marginal bone loss and caries. Differences were considered significant at a 5% level.

RESULTS

Two hundred and ninety (65%) of the root filled teeth survived at follow-up. Baseline variables associated with low odds for tooth survival were mandibular molar, maxillary premolar, prefabricated posts other than screw posts, severe marginal bone loss, caries and apical periodontitis (AP). Normal periapical status at follow-up was registered in 49% of the root filled teeth. Baseline variables associated with low odds for normal periapical status (high risk for AP) at follow-up were mandibular molar, maxillary premolar, AP, severe marginal bone loss and inadequate root filling quality. Of the root filled teeth with AP at baseline, 42% had been left untreated during the observation period, and at follow-up, the AP persisted in 57% of these teeth.

CONCLUSIONS

After 20 years, 65% of the root filled teeth had survived and one-third remained with a sound periapical condition, without any further treatment. Almost half of the APs registered at baseline were left without treatment, and more than half of them persisted after 20 years.