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

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.

The Dental Practicality Index - to treat or not to treat

The Dental Practicality Index (DPI) has been designed to describe, on a clinical level, the 'practicality' of restoring a tooth versus referring to secondary care or extraction.The systematic approach of DPI has been shown to improve decision-making and confidence in treatment planning when used by young dentists. In addition, there is good evidence demonstrating that it provides an accurate estimation of the outcome of treatment. The DPI enhances clinician-patient communication and ultimately the consent process.

Fitting of Different Intraradicular Composite Posts to Oval Tooth Root Canals: A Preliminary Assessment

The purpose of the present study was to perform a preliminary analysis of the fitting of different fiber-reinforced composite (GFRC) posts to tooth root canals and determine the resin cement layer thickness. The following GFRC posts were assessed: bundle posts (Rebilda GTTM, VOCO, Germany), sleeve system (SAPTM, Angelus Ind, Brazil), and accessory posts (ReforpinTM, Angelus, Brazil). Twenty-four freshly extracted mandibular single-rooted pre-molars were endodontically treated and divided into six groups, according to the type of GFRC post and resin cement (self-adhesive or conventional dual-cured). Then, specimens were cross-sectioned and inspected by optical microscopy regarding the cement layer thickness and presence of defects such as pores, voids, or fissures were assessed. Bundle and accessory posts revealed a regular distribution of resin cement with a lower number of voids than found with sleeve systems. The sleeve system posts showed poor fitting at the apical portion of the root canals. The type of resin cement did not affect the thickness of the interface, although both bundle and accessory posts allow a better distribution of resin cement and fibers. The present preliminary study reveals interesting insights on the fitting of bundle and accessory posts to root dentin and resin cement layer thickness in oval-shape root canals. The sleeve system posts showed adequate fitting only at the coronal portion of the canals.

Effect of Dental Practicality Index training using an online video on decision-making and confidence level in treatment planning by dental undergraduates

Objectives

The purpose of this study was to evaluate the effect of Dental Practicality Index (DPI) training using an online video on the treatment planning decisions and confidence level of dental undergraduates (DUs).

Materials and Methods

Ninety-four DUs were shown 15 clinical case scenarios and asked to decide on treatment plans based on 4 treatment options. The most appropriate treatment plan had been decided by a consensus panel of experienced dentists. DUs then underwent DPI training using an online video. In a post-DPI-training test, DUs were shown the same clinical case scenarios and asked to assign the best treatment option. After 6 weeks, DUs were retested to assess their knowledge retention. In all 3 tests, DUs completed the confidence level scale questionnaire. Data were analyzed using the related-samples Wilcoxon signed rank test and the independent-samples Mann-Whitney U test with the level of significance set at p < 0.05.

Results

DPI training significantly improved the mean scores of the DUs from 7.53 in the pre-DPI-training test to 9.01 in the post-DPI-training test (p < 0.001). After 6 weeks, the mean scores decreased marginally to 8.87 in the retention test (p = 0.563). DPI training increased their confidence level from 5.68 pre-DPI training to 7.09 post-DPI training.

Conclusions

Training DUs using DPI with an online video improved their decision-making and confidence level in treatment planning.

Cost-effectiveness analysis of full versus selective root canal retreatment

AIM

Selective root-canal retreatment has been proposed as an alternative to full retreatment in multirooted, root-canal-filled teeth with evidence of apical pathology, where only the affected root(s) is retreated. Whilst this option may save costs initially, failures and retreatments may compensate for these initial savings. We assessed the cost-effectiveness of full versus selective root-canal retreatment using data from a recent clinical pilot study, employing a modelling approach.

METHODOLOGY

A Markov model was constructed to follow up a previously root-canal treated maxillary molar with apical pathology on a single root (mesio-buccal), receiving either selective or full root-canal retreatment. A private-payer perspective in Dutch health care was adopted. Permanent molar teeth with apical lesions on the mesial root were simulated over the lifetime of initially 50-year-old patients. Teeth could have endodontic complications and require interventions such as retreatment or tooth extraction and replacement. Costs were calculated based on the Dutch dental fee catalogues. Monte-Carlo microsimulations were performed to assess lifetime costs and effectiveness (measured as tooth retention time), and the resulting cost-effectiveness. Probabilistic joint uncertainty and sensitivity analyses were performed, and cost-effectiveness at different willingness-to-pay-thresholds was evaluated.

RESULTS

In the base-case scenario, selective retreatment was less costly (2137; 2.5%-97.5% percentiles: 1944-2340 Euro) and more effective (19.6; 18.3-20.8 Years) than full retreatment (2495; 2305-2671 Euro; 16.5; 15.2-17.9 Years) in 100% of the simulations and regardless of the willingness-to-pay threshold. Only in a worst case scenario was selective retreatment more costly, but remained more effective.

CONCLUSIONS

Selective retreatment, when clinically applicable, is likely to be more cost-effective than full retreatment in endodontically treated molars with persistent apical periodontitis. Our results should be interpreted with caution because the quality of the underlying data is limited.

Tooth survival after endodontic treatment

BACKGROUND

There are several measures that are, or could be, in use in relation to estimating the outcome of endodontic treatments. It is important to reflect on when and why a certain outcome measure is used; when caring for an individual patient it is obvious that the goal always should be a tooth in a healthy state, that is striving to remove any infection and aim for the tooth to have healthy periapical tissues. For patients in general and for society, it is also interesting to know if endodontic treatments will lead to retention of teeth in a functioning state. From epidemiological studies, with high prevalence of root filled teeth with periapical radiolucencies, it is implied that dentists and/or patients accept the retention of a root filled tooth with persistent apical periodontitis. In conjunction with an endodontic treatment the prognosis is considered and since the prognostic factors seem to be somewhat different depending on whether one is considering for example the outcome 'healthy periapical tissues' or 'tooth survival' they are equally important to know. Factors affecting the outcome 'healthy periapical tissues' probably has to do with removal of infection and reconstituting the barrier to prevent leakage whilst 'tooth survival' is more likely associated with factors outside of the classical endodontic field such as restorability and avoidance of further destruction of tooth substance. Objective This narrative review will focus on tooth survival after endodontic treatment and root canal treatment will be the focus. Method The search was performed in PubMed. Results As a crude estimation, there is to be an annual loss of 2% of teeth which have received a root canal treatment. Conclusion Of the pre-, peri- and postoperative factors that have been studied in conjunction with root canal treatments the restoration of the tooth is the factor that has been most extensively studied. Many studies imply that root filled teeth restored with indirect restorations have a better survival than teeth restored with direct restorations, it is not possible to determine whether this indeed is a prognostic factor. Registration None.

Present status and future directions: The restoration of root filled teeth

This narrative review will focus on a number of contemporary considerations relating to the restoration of root filled teeth and future directions for research. Clinicians are now more than ever, aware of the interdependence of the endodontic and restorative aspects of managing root filled teeth, and how these aspects of treatment are fundamental to obtaining the best long-term survival. To obtain the optimal outcomes for patients, clinicians carrying out endodontic treatment should have a vested interest in the restorative phase of the treatment process, as well as an appreciation for the structural and biomechanical effects of endodontic-restorative procedures on restoration and tooth longevity. Furthermore, the currently available research, largely lacks appreciation of occlusal factors in the longevity of root filled teeth, despite surrogate outcomes demonstrating the considerable influence this variable has. Controversies regarding the clinical relevance of minimally invasive endodontic and restorative concepts are largely unanswered with respect to clinical data, and it is therefore, all too easy to dismiss these ideas due to the lack of scientific evidence. However, conceptually, minimally invasive endodontic-restorative philosophies appear to be valid, and therefore, in the pursuit of improved clinical outcomes, it is important that the efficacies of these treatment protocols are determined. Alongside an increased awareness of the preservation of tooth structure, developments in adhesive bonding, ceramic materials and the inevitable integration of digital dentistry, there is also a need to evaluate the efficacy of new treatment philosophies and techniques with well-designed prospective clinical studies.

Periapical status transitions in teeth with posts versus without posts: a retrospective longitudinal radiographic study

OBJECTIVES

The aim of this study was to compare periapical status transitions in teeth after post placement compared with other post-endodontic treatments in root-filled teeth.

MATERIAL AND METHODS

This retrospective longitudinal radiographic study included radiographs of 284 patients with root filled and restored teeth with composite fillings (Endo-fill group, n = 100), crown or fixed prosthesis (Endo-crown group, n = 82) or post and core restorations (Endo-post group, n = 102). All post and core restorations were made of gold alloy. The radiographs taken at the end of endodontic treatment, at the end of post-endodontic treatment and at least 8 months after post-endodontic treatment were evaluated. Post-operative periapical status was assessed according to the periapical index (PAI) and all teeth included in the study had no apical periodontitis preoperatively. Multi-state Markov analysis was used to assess periapical status transitions among the treatment groups.

RESULTS

Of 284 root-filled teeth without apical periodontitis at baseline, 7.7% developed clear apical pathology within a minimum of 8 months observational period. In the Endo-post group 11 (10.78%) teeth transited from Healthy (PAI 1) to Disease (PAI 2-4) state compared with eight (9.75%) in the Endo-crown group and four (4%) in the Endo-fill group. The transition probabilities from Healthy (PAI 1) to Mild diseased (PAI 2) were 17.5% in the Endo-post group, 13.1% in the Endo-crown group and 5.3% in the Endo-fill group. Multivariate analysis showed that teeth in the Endo-fill group had 60% lower hazard to transit from Healthy (PAI 1) to Mild diseased (PAI 2) state [HR 0.40; 95% CI 0.12, 0.94]. A period exceeding 8 months between the end of the endodontic treatment and prosthetic treatment significantly increased the hazard of disease progression by three times compared with a period of ≤8 months [HR 3.16; 95% CI 1.06, 9.42].

CONCLUSIONS

Teeth without radiographic lesions at baseline and restored with posts had higher hazard to transit from healthy to diseased periapical status compared with teeth restored with composite restorations. Controlled clinical trials with longer follow-up periods are needed to validate these findings.

Pulpotomy for treatment of complicated crown fractures in permanent teeth: A systematic review

Background

Consensus on the treatment of choice for complicated crown fractures of teeth is limited. Recent guidance recommends vital‐pulp‐therapy; however, the preferred type is not specified. Higher success rates for pulpotomy compared to pulp‐capping have been documented, which suggests pulpotomy may be a preferable option for complicated crown‐fractures.

Objectives

The purpose of this systematic review was to determine the success rate of pulpotomy (partial and complete) on teeth that suffered complicated crown fractures. Participants: patients who have suffered a complicated crown fracture to an anterior permanent tooth. Intervention: pulpotomy (partial or complete). Comparator: pulp‐capping or root canal treatment. Outcome: combined clinical and radiographic success at or after 12 months.

Methods

A systematic literature using key search terms was conducted using PubMed, Web of Science and Cochrane‐Central‐Register‐of‐Controlled‐Trials (CENTRAL) as well as a grey literature search from inception to May 2021 and without language restricted to English. Strict inclusion criteria were applied. A standardized tool with defined criteria to assess the risk of bias in each study was used. For non‐randomized comparative trials, the Robins‐I tool was used while the Newcastle‐Ottawa scale was used for non‐comparative non‐randomized studies.

Results

Seven retrospective clinical studies were included. The studies reported high success rates for pulpotomy with overall success ranges for partial or complete pulpotomy ranging from 75% to 96%. One study compared the success rates of pulpotomy to an alternative treatment option pulp capping (90.9% vs. 67%, respectively). Due to the lack of homogeneity in the included studies, a meta‐analysis was not possible.

Discussion

This review highlights the limited evidence based for the current guidance on treatment of complicated crown fractures. The findings of the review indicate high success rates for pulpotomy; however, there is a moderate risk of bias and small sample sizes in the included studies with the result that the overall results should be interpreted with caution.

Conclusion

Within the limitations of this review, the benefits and high success rates reported for partial pulpotomy suggest this procedure, rather than pulp‐capping, should be considered as the treatment of choice for both immature and mature teeth that have suffered complicated crown‐fractures.

European Society of Endodontology position statement: The restoration of root filled teeth

This position statement on the restoration of root filled teeth represents the consensus of an expert committee, convened by the European Society of Endodontology (ESE). Current clinical and scientific evidence, as well as the expertise of the committee, have been used to develop this statement. The aim is to provide clinicians with evidence-based principles for decision-making on the choice of restoration following the completion of root canal treatment. By discussing the evidence in relation to key topics regarding post-endodontic restoration, a series of clinical recommendations are made. The scientific basis of the recommendations made in this paper can be found in a recently published review article (Bhuva et al. 2021, International Endodontic Journal, https://doi.org/10.1111/iej.13438). It is the intention of the committee to update this statement as further evidence emerges.

Prognostic validity of the Periapical and Endodontic Status Scale for the radiographically assessed 2-year treatment outcomes in teeth with apical periodontitis: a prospective clinical study

Background

Endodontic treatment planning and treatment success evaluation are largely based on radiographic assessment of anatomical and treatment-related parameters of teeth with apical periodontitis (AP). This prospective clinical study aimed to assess radiographically the 2-year endodontic treatment outcomes for teeth with AP, and to evaluate prognostic validity of Periapical and Endodontic Status Scale (PESS).

Methods

A total of 128 patients, representing 176 teeth with AP were examined by cone-beam computed tomography at baseline and at 24 months after endodontic treatment. Treatment outcome was evaluated using estimates of periapical radiolucency and the relationship between anatomical structures and location. The strength of the associations between these and treatment-related parameters was tested by logistic regression analysis. PESS sensitivity and specificity were calculated for every treatment risk group (low, moderate, high) of teeth.

Results

One hundred and fifty-seven teeth, representing 350 root canals had a positive treatment outcome, while 19 teeth, representing 53 root canals had a negative treatment outcome at 24 months. The probability of negative outcome was 25 times higher in the moderate/high-risk group than in the mild-risk group of teeth (OR = 25.1; 95%CI [12.2–51.5]). Pre-treatment complications and retreatment cases with radiolucency were associated with negative outcomes (OR = 35.9; 95%CI [12.6–102.4]; OR = 26.437; 95%CI [10.9–64.1], respectively). PESS sensitivity and specificity was over 80% in all risk groups except for high risk group, due to very low number of cases.

Conclusions

Endodontic treatment outcome depends on the severity of periapical changes. The presence of complications and retreatment cases with periapical lesions are associated with negative treatment outcome. The PESS is a valid instrument to predict outcome of teeth with low-moderate treatment risk of AP.

Influence of Minimally Invasive Access Cavity Designs on the Fracture Resistance of Endodontically Treated Mandibular Molars Subjected to Thermocycling and Dynamic Loading

INTRODUCTION

The aim of this study was to investigate the fracture resistance of endodontically treated and restored permanent mandibular molars with minimally invasive access cavities subjected to thermocycling and dynamic loading.

METHODS

Forty first and second mandibular molars were randomly assigned to 4 groups (n = 10/group) as follows: group 1, control (intact teeth); group 2, traditional access cavity (TradAC); group 3, conservative access cavity (ConsAC); and group 4, truss access cavity (TrecAC). After endodontic treatment, teeth were restored with SDR core (Dentsply Caulk, Milford, DE) and subjected to thermocycling followed by dynamic and static loading with a multiaxial fatigue testing machine (Instron, Canton, MA). The maximum load to fracture and pattern of failure (restorable/unrestorable) were recorded. Data were evaluated with analysis of variance and the Tukey post hoc test for multiple comparisons.

RESULTS

Fracture resistance of the samples in the control group were higher than those in the experimental groups (P < .005). TradAC exhibited the least resistance to fracture (P < .005). There was no statistically significant difference in the fracture resistance of ConsAC and TrecAC (P = .361) Unrestorable fractures were more frequent in the TradAC group compared with all other groups.

CONCLUSIONS

Mandibular molars with ConsAC and TrecAC exhibited superior fracture resistance compared with TradAC. TradAC had the highest number of unrestorable fractures.

Fracture resistance of endodontically-treated maxillary premolars restored with different type of posts and direct composite reconstructions: A systematic review and meta-analysis of in vitro studies

OBJECTIVE

To conduct a systematic review and meta-analysis to assess if the presence of an endodontic post may increase the fracture resistance of endodontically-treated maxillary premolars directly restored with composite.

METHODS

A comprehensive systematic literature search according to the PRISMA statement was conducted to assess in vitro studies including endodontically-treated maxillary premolars, restored with different type of posts supporting direct composite reconstructions. Two groups of meta-analyses were performed using fixed effects model and additional Trial Sequential Analysis (TSA) was carried out. Moreover, risk of bias was conducted and quality of evidence for any performed meta-analysis was assessed using Grading of Recommendations Assessment, Development and Evaluation (GRADE).

RESULTS

Twenty-four articles met the inclusion criteria and 13 studies also underwent quantitative evaluation. Fracture resistance of endodontically-treated premolars restored with fiber posts was significantly less than sound teeth (p value: < 0.00001), however endodontically-treated premolars with a fiber post provided an increase in fracture resistance when compared to equivalent teeth restored without post (p value: 0.003). TSA revealed high power of both meta-analyses. Moderate risk of bias was reported in 23/24 studies; only 1 study showed high risk of bias. GRADE system showed moderate strength of evidence due to the presence of a study with high risk of bias and to wide confidence intervals.

SIGNIFICANCE

Within the limitation of the present systematic review and meta-analysis, it can be concluded that endodontically-treated maxillary premolars restored with a fiber post and direct composite restoration demonstrated increased fracture resistance when compared to equivalent teeth without post.

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.

Magnetic extrusion technique for restoring severely compromised teeth: A case report

An orthodontic magnetic extrusion technique is described for the management of an extensively damaged maxillary premolar. A cylindrical neodymium-iron-boron (Nd₂Fe₁₄B) magnet was attached to the remaining tooth structure, and a second magnet was placed on a resin-bonded partial denture. A 4.5-mm extrusion was obtained after 3 adjustments, and the tooth was prepared with a 3-mm buccal and 2-mm lingual ferrule by following a biologically oriented preparation technique and restored with a monolithic zirconia crown. Eighteen months after completing the treatment, no evidence of soft tissue dehiscence, abnormal tooth mobility, endodontic failure, or root resorption was found.

Tooth survival following root canal treatment by general dental practitioners in a Swedish county - a 10-year follow-up study of a historical cohort

AIM

To evaluate the 10-year survival rate of root filled teeth treated by general dental practitioners (GDPs), and to identify possible prognostic factors.

METHODOLOGY

In 2006, 3676 individuals had at least one tooth root filled by a GDP within the Norrbotten Public Dental Service, Sweden. Over the next 10 years, 331 individuals died and were excluded. A random sample of 302 of the remaining individuals was included in the study, of whom 280 (n = 280 teeth) were included in the analysis. Dental records were reviewed retrospectively by a calibrated researcher to collect predetermined data regarding individual, pre-operative, intra-operative and post-operative factors. The outcome measure was tooth extraction over time, and cases with no events were censored, regardless of apical status or symptoms, until last known date of tooth survival. In case of missing data, individuals were recalled for a control visit. Kaplan-Meier survival tables and Cox regression models were used for analysis. P < 0.05 was considered statistically significant.

RESULTS

The cumulative 10-year survival was 81.7% (standard error: 2.6%), and the mean incidence of tooth extraction during the 10 years was 1.8% per year. The univariate analysis identified three possible prognostic factors (P < 0.05) that were associated with extraction: molars, two or more emergency inter-appointment visits during the treatment, and root canal treatments consisting of five or more separate sessions. A multivariate regression analysis revealed no significant relationships for the variables gender, tooth type, number of contacts, any emergency visits during endodontic treatment, number of sessions to complete endodontic treatment, pulp diagnosis, or type of permanent restoration and extraction.

CONCLUSIONS

The mean incidence of tooth loss over the first 10 years after completion of root canal treatment performed by a GDP was approximately 2% per year. No prognostic factors could be identified.