Treatment outcome in endodontics: the Toronto study--phase 4: initial treatment

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.

Confocal laser scanning evaluation of the influence of ledges on root canal disinfection

The aim was to analyse the influence of an apical ledge on root canal disinfection. Forty-four single-rooted teeth were micro-CT scanned and inoculated with Enterococcus faecalis. In Group S shaping was performed with ProTaper Next (PTN) up to X3 at working length (WL). In Group L an apical ledge was created with K-Files #40 and shaping completed up to PTN X3. NaOCl 5% and EDTA 10% irrigant solutions were alternated. Confocal laser scanning microscope (CLSM) and viability staining were used to analyse the proportions of dead (red) and live (green) bacteria and penetration ability inside dentinal tubules. Data were analysed with the Mann-Whitney test with Bonferroni correction (p < 0.05). In Group L the amount of red fluorescence resulted significantly lower, and penetration ability was decreased in the apical and middle portion (p < 0.05). The presence of an apical ledge may negatively influence the disinfection both in the apical and middle third.

Antimicrobial efficacy of DJK-5 peptide in combination with EDTA against biofilms in dentinal tubules: Primary irrigation, recovery and re-irrigation

AIM

To investigate the dynamic recovery of biofilms within dentinal tubules after primary irrigation with different protocols, and to evaluate the efficacy of various re-irrigation protocols on recovered biofilm, considering factors such as smear layer, nutrient conditions, and primary irrigants.

METHODOLOGY

A total of 416 mono or multi-species biofilms samples were prepared from human teeth and incubated for 3 weeks. After inducing a smear layer on half of the samples, all specimens were irrigated with one of the following irrigant sequences: (1) 6% NaOCl +17% EDTA, (2) 6% NaOCl +8.5% EDTA, (3) 6% NaOCl and (8.5% EDTA +10 μg/mL DJK-5 antimicrobial peptide), or (4) sterile water. Thirty-two samples were used to assess immediate effect, whilst the rest were re-incubated to assess biofilms recovery. Nutrient conditions were defined based on whether culture media were changed (nutrient-rich) or not (nutrient-poor) during re-incubation. After 16 weeks, recovered biofilms underwent re-irrigation using four additional protocols, with or without DJK-5 peptide, based on primary irrigants. Confocal laser scanning microscopy was employed to evaluate immediate irrigant effects, biofilms recovery intervals (1, 3, 5, 8, 12, and 16 weeks after primary irrigation), and re-irrigation effects at the 16-week. Statistical analysis included one-way anova and two-way mixed anova tests.

RESULTS

The DJK-5 peptide irrigation protocols demonstrated the highest killing rates during primary irrigation and resulted in a longer biofilms recovery time of 16 weeks compared to non-peptide protocols (p < .001). Both primary irrigation type and smear layer presence significantly influenced biofilms recovery (p < .001). In the absence of smear layer, re-irrigation efficacy didn't significantly differ from primary irrigation, regardless of primary irrigation type or nutrient conditions. However, with a smear layer present, re-irrigation led to significantly higher proportion of dead bacteria compared to primary irrigation (p < .05). Inclusion of the DJK-5 peptide into the re-irrigation protocol displayed superior killing rate compared to other protocols (p < .001).

CONCLUSIONS

Biofilms exhibited susceptibility to both peptide and non-peptide protocols during re-irrigation, irrespective of nutrient conditions or primary irrigation protocols. The DJK-5 peptide irrigation protocols consistently displayed superior effectiveness compared to non-peptide protocols.

GIRFT and Measuring Outcomes in MCNs: endodontics in 646 teeth treated in Tier 2 (Primary Care) and Tier 3 (Secondary Care) settings in England

AIM

This paper aims to assess the complexity, quality and outcome of endodontic treatment provided in Managed Clinical Networks (MCNs) in England to understand if we are "getting it right first time" (GIRFT).

METHODS

In a convenient sample of endodontic treatments provided between May 2011 and April 2017, the complexity of teeth treated, the quality of treatment procedure, the radiographic appearance of root fillings, as well as clinical and radiographic healing were retrospectively assessed using records taken as part of treatment. Trained, calibrated examiners independently scored radiographs using previously published scoring systems.

RESULTS

646 teeth were followed up for 24.7 months (standard deviation [SD] 17.08). The average age of those patients treated was 46.7 years (SD 15.38) with 48.3% being male. Of teeth treated, 70.4% were of complexity level 3. 88.2% of teeth were asymptomatic, and 80% demonstrated complete radiographic healing. Procedural errors inhibited achieving correct working length and taper, with more voids within root canal fillings. When patency filing was reported as being carried out, complete radiographic healing was more likely.

CONCLUSIONS

It is possible to collate outcome data in the NHS system, especially if there is provision for ongoing follow up and time allocated for collection of data. Endodontic treatment provided within primary and secondary care settings are of high quality, with outcomes being better with single operators carrying out high volumes of endodontic treatment.

Outcomes of nonsurgical endodontic treatment under general anesthesia in special health care needs: An observational study

BACKGROUND AND AIM

The alarming rise in the number of people with special health care needs (SHCNs) necessitates a paradigm shift in how to approach their oral health needs. General anesthesia (GA) is a valuable technique for facilitating dental procedures in patients with SHCNs who may not be able to tolerate treatment without it. The aim was to assess nonsurgical endodontic treatment and outcomes in patients with SHCNs performed under GA.

METHOD

Seventy-eight permanent teeth in 33 patients who received nonsurgical endodontic treatment under GA were included between 2018 and 2022 in SHCNs hospital clinics. The demographic data, types of SHCNs, pulpal and periapical diagnosis, type of treatment, and material used were analyzed. All patients were recalled for clinical and radiographic examinations. Pre-treatment and recall periapical radiographs were evaluated and scored using the Periapical Index (PAI).

RESULTS

Autism and Attention deficit hyperactivity disorder were 39.4% of patients treated. Most treatments delivered were primary nonsurgical root canal treatment (95%). Warm vertical compaction of gutta-percha for obturation accounted for 88% of cases treated. Single cone obturation technique was used in 9 cases (12%) utilizing tricalcium silicate sealer. At the recall visits, 98.7% of teeth treated had survived. Twelve teeth have pre-treatment periapical lesions, and all healed except one. Female patients were found to have higher scores of PAI compared to male patients (23.7% vs 7.5%), yet insignificant. Only 10 patients with nonsurgical root canal treatment reported recurrent caries.

CONCLUSION

This study demonstrates a high survival rate for nonsurgical endodontic treatment performed under GA in a cohort of patients with SHCNs. Interestingly, patients with social and communication disorders received the highest proportion of treatments under GA. These findings highlight the potential of GA-facilitated endodontics for this population. However, further research is warranted to explore additional methods for optimizing oral health outcomes in SHCNs.

Effect of Orthodontic Treatment on the Outcomes of Endodontically Treated Teeth: A Cone-Beam Computed Tomography Analysis

INTRODUCTION

Often there is the need of moving endodontically treated teeth. Orthodontic movement may have no effect on the prognosis of teeth with root canal treatment (RCT). To verify this subject, we evaluated the effect of orthodontic movement on the prognosis of RCT teeth using cone-beam computed tomography (CBCT) and further explored the influence of orthodontic movement on the prognosis of RCT teeth with and without apical periodontitis (AP).

METHODS

This retrospective study was conducted by evaluating 169 RCT teeth of 100 patients who had undergone fixed orthodontic treatment. AP was assessed and classified using the CBCT periapical index. Univariate analysis of RCT outcome was performed for the total RCT group, RCT without AP group and RCT with AP group. Multivariate logistic regression was performed for the total RCT group and RCT without AP group, respectively, but not for the RCT with AP group. Variables related to the prognosis of RCT were included, such as age, gender, tooth position, RCT quality, coronal restoration quality, periodontal condition, orthodontic traction distance, and orthodontic rotation angle.

RESULTS

The orthodontic traction distance and rotation angle were not significantly correlated to the RCT outcomes, regardless of the presence of AP. Among the total RCT group, teeth with unqualified RCT (odds ratio = 3.42, P = .004) and inadequate coronal restoration (odds ratio = 4.40, P = .031) had a lower success rate. Of the 97 RCT teeth without AP, unqualified RCT was a risk factor for treatment failure (odds ratio = 3.55, P = .041). Of the 72 RCT teeth with AP, the univariate analysis showed that RCT quality were significantly related to the outcome (P = .042).

CONCLUSIONS

Orthodontic movement had no effect on the prognosis of RCT teeth regardless of the presence of AP.

Factors Influencing Non-Surgical Root Canal Treatment Outcomes in Mandibular Second Molars: A Retrospective Cone-Beam Computed Tomography Analysis

Background/Objectives: This study aimed to investigate the influence of the root canal morphology and various treatment variables on the outcomes of root canal treatments (RCTs) in mandibular second molars, assessed through cone-beam computed tomography (CBCT) imaging. Methods: A total of 150 CBCT images were examined, comprising 100 cases of persistent endodontic infections and 50 of previously treated root canals with normal apices in the mandibular second molars. CBCT was utilized to evaluate the root canal configuration, the radiographic quality of coronal restorations and treated canal systems, and the presence of periapical lesions. Statistical analyses were performed to explore the correlations between these factors. Results: The presence of a C-shaped root canal configuration did not demonstrate a significant correlation with periapical lesions (p = 0.05). Factors influencing endodontic treatment outcomes included missing canals (p = 0.018), underfilling or overfilling (p = 0.045), and inadequate coronal restoration (p = 0.006). Missing a canal was identified as the variable most significantly associated with periapical lesions (OR = 3.103). Inhomogeneous root canal obturation was more commonly observed in C-shaped root canals (p < 0.001). Conclusions: Regardless of the root canal morphology of mandibular second molars, successful RCT depends on thorough disinfection to eliminate any untreated canals, precise three-dimensional filling of the canals at the correct working length, and a securely sealed coronal restoration to prevent leakage.

Factors associated with the outcome of root canal treatment-A cohort study conducted in a private practice

AIM

To investigate the association of various pre-, intra- and post-operative factors on root canal treatment outcome.

METHODOLOGY

In this cohort study, primary or secondary root canal treatment of mature permanent teeth was performed by a single endodontist in a private practice over 13 years, and followed 1-4 years after treatment. Treatment details and clinical and radiographic data were collected. The proportion of successfully treated teeth and roots based on strict radiographic (periapical index (PAI) ≤2) and clinical criteria (absence of pain, swelling or sinus tract) was estimated. To evaluate joint associations of prognostic factors and treatment success probability, 44 pre, intra- and post-operative factors were investigated using bivariate associations, and a multiple logistic regression model was fitted using Generalized Estimating Equations.

RESULTS

1259 teeth (2445 roots, 3149 canals) were assessed with a recall rate of 91%. The proportion of successfully treated teeth was 79.9% [95% confidence interval 77.7-82.1]. Eleven prognostic factors were identified that significantly reduced the odds ratio (OR) for treatment success at tooth level. Six were preoperative: injury history (OR = 0.05[0.01-0.24]), root PAI (OR = 0.29[0.20-0.42], 0.21[0.13-0.34] and 0.22[0.12-0.42] for PAI = 3, 4 and 5, respectively, against PAI = 1), lesion diameter (OR = 0.30[0.21-0.43] and 0.24[0.16-0.37] for diameters of 1-5 mm and ≥6 mm, respectively, against no lesion), tooth type (OR = 0.51[0.27-0.97] and OR = 0.45[0.24-0.83] for premolars and molars, respectively, against incisors or canines), tenderness to periapical palpation (OR = 0.64[0.43-0.94]) and two canals per root (OR = 0.67[0.54-0.83]). Four factors were intraoperative: root filling of unsatisfactory quality (OR = 0.18[0.08-0.40]) or extending beyond or shorter than 2 mm from the apex (OR = 0.44[0.26-0.75] and 0.62[0.40-0.97] respectively), resin sealer (OR = 0.58[0.39-0.87] against bioceramic sealer) and single visit treatment (OR = 0.40[0.21-0.75] against multiple visits). One factor was post-operative: defective coronal restoration (OR = 0.35[0.21-0.56]).

CONCLUSION

The following factors were associated with unsuccessful root canal treatment: (i) history of injury, apical periodontitis with increased severity (larger lesion, higher PAI, tenderness to periapical palpation), or complicated anatomic conditions (premolar or molar, two canals in a single root); (ii) technically suboptimal root filling (of unsatisfactory quality or not ending within 2 mm of radiographic apex) performed in a single-visit, or use of resin sealer instead of novel bioceramic sealer; (iii) suboptimal quality coronal restoration.

Outcome of Contemporary Nonsurgical Endodontic Retreatment: A Systematic Review of Randomized Controlled Trials and Cohort Studies

INTRODUCTION

The success rates of NS-ReTx have varied across decades of prior research. Nonetheless, recent endodontic advances have substantially enhanced case management. This systematic review aimed to identify rigorous studies on contemporary NS-ReTx, investigating both periapical healing-evaluated strictly for complete resolution or loosely for size reduction of periapical radiolucency-and success, denoting clinical normalcy combined with periapical healing.

METHODS

We systematically searched MEDLINE, Embase, Web of Science, the Cochrane Library, and gray literature from January 1988 to December 2022. Article selection and data extraction were independently conducted by 3 reviewers. Selected studies underwent risk of bias assessment, and evidence quality using the Grading of Recommendations, Assessment, Development, and Evaluation approach. Meta-analysis and meta-regression established pooled outcome rates, 95% confidence intervals (CIs), and significant clinical prognostic factors (P < .05).

RESULTS

Twenty-nine articles were included. Pooled periapical healing rates using strict and loose criteria were 78.8% (95% CI: 75.2-82.4) and 87.5% (95% CI: 83.8-91.2), respectively. Pooled success rates using strict and loose criteria were 78.0% (95% CI: 74.9-81.2) and 86.4% (95% CI: 82.6-90.1), respectively. Meta-regression analyses revealed significant influences on NS-ReTx outcomes (P < .05), including periapical status, lesion size, apical root filling extent, and follow-up duration.

CONCLUSIONS

Contemporary NS-ReTx shows encouraging outcomes, achieving periapical healing and success rates ranging from approximately 78% (strict criteria) to 87% (loose criteria). The absence of or smaller preoperative lesions, adequate root filling length, and extended follow-ups significantly improve NS-ReTx outcomes. Integrating these factors into treatment planning is pivotal for optimizing the outcome of NS-ReTx.

Outcome of nonsurgical management of large cyst-like periapical lesions using a modified apical negative pressure irrigation system: a case series study

OBJECTIVE

To assess the effectiveness of a self-constructed modified apical negative pressure irrigation (ANPI) system employing commonly used clinical instruments in nonsurgical root canal therapy (NSRCT) for large cyst-like periapical lesions (LCPLs).

METHODS

From 2017 to 2022, 35 patients diagnosed with LCPLs (5-15 mm) via preoperative clinical and radiographic evaluations of endodontic origin underwent NSRCT combined with ANPI. These patients were subjected to postoperative clinical and radiographic follow-up at 3 months, 6 months, 1 year, 2 years, 3 years, and 4 years, with a CBCT scan specifically conducted at 6-month follow-up. Through the reconstruction of three-dimensional cone beam computed tomography (CBCT) data, an early prognosis was facilitated by monitoring changes in lesion volume. Various treatment predictors-including sex, type of treatment, lesion size, preoperative pain, jaw, type of teeth involved, sealer extrusion, and the number of root canals-were meticulously analyzed. The evaluation of post-treatment outcomes leveraged both clinical observations and radiographic data collected during the follow-up periods. The Kruskal‒Wallis test and one-way ANOVA were also conducted to determine the independent factors influencing treatment outcomes. A significance level of 5% was established.

RESULTS

Thirty-five teeth from 35 patients with a median age of 28 years (range 24-34) were treated; the median follow-up duration was 19 months (range 12-26). The overall success rate was 91.4%, with a median lesion reduction of 77.0% (range 54.2-96.4%) at 6 months. Patients under 30 years of age exhibited a significantly greater success rate than older patients did (100.0% vs. 80.0%, p = 0.037). Other factors, such as sex, jaw, treatment type, preoperative pain, cyst size, tooth location, sealer extrusion, and the number of roots, did not significantly impact treatment outcomes.

CONCLUSIONS

Despite limitations related to the observational case-series study design and relatively small sample size, our findings suggest that utilizing the ANPI in the NSRCT for LCPLs may hold promise. The notably higher success rate in patients younger than 30 years is worth noting.

Expert consensus on difficulty assessment of endodontic therapy

Endodontic diseases are a kind of chronic infectious oral disease. Common endodontic treatment concepts are based on the removal of inflamed or necrotic pulp tissue and the replacement by gutta-percha. However, it is very essential for endodontic treatment to debride the root canal system and prevent the root canal system from bacterial reinfection after root canal therapy (RCT). Recent research, encompassing bacterial etiology and advanced imaging techniques, contributes to our understanding of the root canal system's anatomy intricacies and the technique sensitivity of RCT. Success in RCT hinges on factors like patients, infection severity, root canal anatomy, and treatment techniques. Therefore, improving disease management is a key issue to combat endodontic diseases and cure periapical lesions. The clinical difficulty assessment system of RCT is established based on patient conditions, tooth conditions, root canal configuration, and root canal needing retreatment, and emphasizes pre-treatment risk assessment for optimal outcomes. The findings suggest that the presence of risk factors may correlate with the challenge of achieving the high standard required for RCT. These insights contribute not only to improve education but also aid practitioners in treatment planning and referral decision-making within the field of endodontics.

The Outcomes of Endodontically Treated Teeth Restored with Custom-Made Cast Post-and-Core Restorations: A Retrospective Cohort Study

INTRODUCTION

Custom-made cast post-and-core (CMCPC) restorations have long been used to restore structurally deficient endodontically treated teeth (ETT). However, the evidence regarding their impact on the outcomes of ETT is largely inconclusive. This study evaluated the long-term treatment outcome of ETT restored with CMCPC.

METHODS

This retrospective cohort study examined the dental records of patients that received CMCPC at a specialty private practice in Toronto, Canada between 1999 and 2021. The proportion of ETT with complete periapical healing and those that survived were estimated, and prognostic factors were investigated using multiple logistic and Cox regression analyses respectively (P < .05).

RESULTS

A total of 500 and 1000 teeth met periapical healing and survival criteria, respectively. The periapical healing rate was 88.8% and was associated with the presence of baseline periapical radiolucency [odds ratio = 0.1; 95% confidence interval (CI), 0.05-0.2; P < .001]. The survival after a median follow-up time of 52.9 months (interquartile range: 26.5-99.4) was 90.1% and was associated with <75% of root length in bone [hazard ratio (HR) = 2.6; 95% CI, 1.0-6.6; P = .033], type and quality of final restoration (HR = 2.09; 95% CI, 1.1-3.9; P = .020; HR = 2.3; 95% CI, 1.2-4.5; P = .008, respectively), and the presence of periapical radiolucency at the latest recall (HR = 3.2; 95% CI, 1.7-6.3; P < .001).

CONCLUSIONS

The outcome of ETT restored with CMCPC was favorable. CMCPC may be regarded as a viable restorative option for structurally deficient ETT.

Retrospective Assessment of Endodontically Treated Teeth Replaced by Dental Implants

INTRODUCTION

This study investigated endodontically treated teeth that were replaced by dental implants at the University of North Carolina (UNC) at Chapel Hill School of Dentistry. The primary objective of this study was to determine the reasons leading to the extraction of endodontically treated teeth and their subsequent replacement with dental implants. The secondary objective was to evaluate the proportion of these teeth that, according to experienced endodontists, could have been preserved.

METHODS

The UNC-Chapel Hill's dental electronic health records between 2004 and 2019 were probed for implant placement that replaced root canal-treated teeth. Preextraction radiographs and clinical charts were examined to ascertain the primary reason related to the extraction and to compile a profile for each case. In cases in which endodontic failure was the primary reason for extraction, radiographs and clinical findings were evaluated by 2experienced endodontists to assess potential treatment options.

RESULTS

Between 2004 and 2019, 29.3% (1564 of 5229) of teeth replaced by dental implants at UNC School of Dentistry had undergone root canal treatment, with the mandibular first molar being the most commonly replaced tooth. The leading reasons for extraction were recurrent caries associated with defective restoration (26.6%), fracture of coronal structure (21.5%), vertical root fracture (20.9%), compromised periodontal condition (13.8%), and endodontic failure (2.4%). Two experienced endodontists evaluated extractions due to endodontic failure and concluded that 61.7% of them could have been candidates for endodontic retreatment.

CONCLUSION

Substantial loss of tooth structure was the leading cause of extraction of root canal-treated teeth, followed by vertical root fracture and periodontal disease. Although endodontic failure constituted a minor portion of the reasons for extraction, a considerable number of teeth were extracted due to vertical root fractures following root canal treatment. A significant proportion of the extracted teeth due to endodontic failure could have been considered as potential candidates for endodontic retreatment.

The flow behavior and sealing ability of calcium silicate root canal cement containing dimethyl sulfoxide: An in vitro study

INTRODUCTION

To develop a calcium silicate (CaSi)-based cement containing dimethyl sulfoxide (DMSO) and cement deliver device for new root canal filling technique, and to assess the flow behavior, leakage, and root canal filling quality of CaSi containing DMSO.

METHODS

CaSi containing DMSO (CSC-DMSO) and CaSi containing PEG (CSC-PEG) were prepared, and the flow characteristics of both cements were compared in gypsum and resin channels using a high-speed camera. Eight root canals were obturated by CSC-DMSO or CSC-PEG using a cement delivery device, and root canal filling quality was assessed in terms of filling length using periapical radiographs. The filling length was evaluated by 'apico-coronal extension,' measuring length in reference to apical constriction. Microleakage was measured for thirty human molars that were randomly filled with CSC-DMSO, CSC-PEG, or gutta-percha and AH plus. Preliminary obturation of CSC-DMSO with cement delivery device in human teeth was analyzed in terms of filling length and void, using periapical radiographs. Statistical analysis was performed with the Kruskal Wallis test for simulated root canal fillings and one-way ANOVA for leakage test.

RESULTS

The flow speed of CSC-DMSO reduced in gypsum channels compared to resin channels, but CSC-PEG did not exhibit significant differences in the channels. The median absolute value of apico-coronal extension was significantly lower in CSC-DMSO compared to CSC-PEG (p < 0.05). Microleakage did not statistically differ between the groups (p > 0.05). In the preliminary obturation, the mean apico-coronal extension of CSC-DMSO was -0.297 ± 0.724 mm, while CSC-PEG was not feasible due to excess apical extrusions.

CONCLUSIONS

CSC-DMSO could be considered as an alternative filling material for root canal obturation.

Factors influencing the outcome of nonsurgical root canal treatment and retreatment: A retrospective study

This study assessed the influence of diverse variables on the outcome of nonsurgical root canal treatment/retreatment. In general, 304 teeth from 218 patients were treated/retreated and the outcome evaluated by the periapical index (PAI). Teeth with apical periodontitis lesions that have not completely healed were classified as success or failure based on lenient and rigid criteria, respectively. Findings were evaluated using a logistic regression analysis. The overall success rates were 74% and 82% using the PAI-rigid and lenient success criteria, respectively. Specifically for treatment, the success rates were 73% (rigid) and 82% (lenient), while for retreatment they were 78% (rigid) and 83% (lenient). The treatment outcome was negatively affected by overextension, presence of preoperative lesion, lesion size >10 mm, and higher number of treatment visits (with no intracanal medication). Regarding retreatment, the chance of success was greater for teeth with adequate coronal restorations.

In vitro assessment of the roles of initial preparation size and solvent application on apically extruded debris in endodontically treated teeth

Background

This study investigated the effects of solvent use and initial canal enlargement size on apically extruded debris (AED).

Methods

The palatal roots of 60 upper molars were assigned to two groups based on the initial preparation size: F3 or F4 ProTaper Universal files. The roots were obturated using the single-cone technique. Each group was subdivided based on the retreatment procedures: with or without solvent. After evaporation, the Eppendorf tubes were weighed using an electronic balance. The data were statistically analyzed (P=0.05).

Results

Using a solvent enhanced the amount of AED in samples initially prepared up to F3 or F4 files (P<0.05). When the solvent was used, the AED was greater in samples initially prepared up to the F4 file (P<0.05); however, when the solvent was omitted, the results were reversed (P<0.05).

Conclusion

Both parameters had a role in AED. Solvents should be used cautiously during root canal retreatment because of the potential for apical extrusion of filling materials. Using files with smaller tapers during initial preparation might be beneficial when considering the amount of AED compared to those with larger tapers.

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.

Full Pulpotomy as a Treatment for Irreversible Pulpitis in Permanent Teeth: A Systematic Review of the Literature Based on Case Reports

The objective of this systematic review was to evaluate the current evidence of case reports where the treatment for permanent teeth with a diagnosis of irreversible pulpitis was a full pulpotomy. This study was carried out by two reviewers following the Preferred Reporting Items for Systematic Reviews and Meta-analyses (PRISMA) guidelines. A systematic electronic search was carried out in the PubMed, Google Scholar, and Scopus databases until the year 2022 to find articles in English where the treatment for irreversible pulpitis in permanent teeth was a full pulpotomy. Literature reviews, in vitro or animal studies, abstracts, and unpublished data were excluded. The intervention, control, and outcome parameters were selected following the "Population, Interventions, Control, and Outcome" (PICO) guidelines. A total of 636 articles were found, and 14 articles were selected to be included in this review. The selected articles describe cases of full pulpotomies in mature permanent teeth with a diagnosis of irreversible pulpitis with a total of 34 (100%) successful cases, where 18 were men and 16 were women, with an average age of 19.20 ± 10.59 years and an average follow-up of 35.82 ± 26.39 months, with 12 months being the minimum follow-up time. The material used most frequently for obturation of the full pulpotomy was mineral trioxide aggregate in 16 cases (47.06%). Within the limitations of this review, full pulpotomy presents a high success rate regardless of the tooth, age, or sex as a treatment for teeth diagnosed with irreversible pulpitis.

Effectiveness of root canal treatment for vital pulps compared with necrotic pulps in the presence or absence of signs of periradicular pathosis: A systematic review and meta-analysis

BACKGROUND

Preoperative pulpal status may influence the outcomes of root canal treatment (RCTx) according to various measures used.

OBJECTIVES

To compare the effectiveness of RCTx of teeth with a vital pulp versus a necrotic pulp, using a range of clinical and patient-related outcomes proposed for the development of S3-level clinical practice guidelines.

METHODS

A search was conducted in the PubMed-MEDLINE, Scopus, EMBASE, Google scholar databases and available repositories, followed by hand searches, until 29 March 2022. Clinical studies published in the English language comparing the stipulated outcomes of RCTx of teeth with vital versus necrotic pulp were included. The Newcastle-Ottawa Scale was adapted to assess study quality. Effects of pulpal status were estimated and expressed as risk ratio (RR) using fixed- and random-effect meta-analyses. The quality of evidence was assessed through the Grading of Recommendations Assessment, Development and Evaluation tool.

RESULTS

Twenty-eight studies published between 1961 and 2021 were included. Five studies have investigated the "tooth survival" outcome, four reported pulpal status was not a significant predictor, consistent with meta-analysis findings (RR: 1.00; 95% CI: 1.00, 1.00; n = 3). Seven studies reported pulpal status had no significant influence on postoperative pain, regardless of duration after treatment. Sixteen studies have analysed "periapical health," and 11 revealed pulpal status had no significant influence. Meta-analyses revealed the influence was not significant if preoperative periapical radiolucency was absent (RR: 0.95; 95% CI: 0.90, 1.00; n = 9) but significant if it was present (RR: 1.12; 95% CI: 1.05, 1.19; n = 11). Most studies were classified as "some concerns" (n = 17) to "low" (n = 9) risk of bias RoB.

DISCUSSION

Evidence is limited and only available for three outcomes when comparing the effectiveness of RCTx in permanent teeth with vital pulp versus pulp necrosis. Nevertheless, the quality of available evidence was moderate to high. The "periapical health" data heterogeneity could be explained by preoperative radiolucency, thus RCTx was found more effective for prevention than the resolution of apical periodontitis.

CONCLUSIONS

There was no significant difference in the "tooth survival," "postoperative pain" and "evidence of apical radiolucency" outcomes of RCTx in teeth with vital or necrotic pulps.

REGISTRATION

PROSPERO database (CRD42021260280).

Efficacy of imaging techniques for the diagnosis of apical periodontitis: A systematic review

BACKGROUND

Apical periodontitis (AP) is a chronic inflammatory response of microbial aetiology. Pathological changes associated with AP may not be visible on radiographic images and may linger without causing any symptoms. Clinicians rely mostly on clinical examination and imaging techniques to establish a diagnosis.

OBJECTIVES

The aim of this review was to answer the following question using the PICO format: In the adult human permanent dentition (P), what is the efficacy of diagnostic imaging of the periapical tissues (I) using histopathology as a reference standard (C) in the diagnosis of apical periodontitis, in terms of diagnostic accuracy (O).

METHODS

MEDLINE, EMBASE, Scopus and Cochrane Library were searched for English articles published through October 2021. At least two independent reviewers evaluated the study design, imaging modality used, histopathological assessment, outcome measures, results and conclusions for each article. The risk of bias was assessed using the Quality Assessment Tool for Diagnostic Accuracy Studies-2.

RESULTS

The initial search strategy identified 544 articles. Seven articles were included for analysis in the final review, all of which involved tissue samples obtained from cadavers. No clinical studies were identified that met the eligibility criteria. A consistently low sensitivity score and negative predictive value were reported for periapical radiography, especially in comparison to CBCT, which scored highly. Both modalities achieved high scores for specificity and positive predictive value. Diagnostic accuracy of CBCT was lower for root-filled teeth in comparison to non-root-filled teeth.

DISCUSSION

Assessment of the periapical tissues using periapical radiographs was shown to have a low to moderate agreement with the histopathological assessment. CBCT was reported to be more accurate than PR and demonstrated a good agreement with histopathology, especially for non-root-filled teeth.

CONCLUSIONS

This review identified a need for greater standardization in methodology and reporting, and as the findings are based on cadaver studies, their clinical relevance must be interpreted with caution.

REGISTRATION

PROSPERO (CRD42021272147).

The Effect of Unintentional AH-Plus Sealer Extrusion on Resolution of Apical Periodontitis After Root Canal Treatment and Retreatment-A Retrospective Case-control Study

INTRODUCTION

This study aimed to investigate the effect of unintentional AH Plus sealer extrusion on the outcome of nonsurgical root canal treatment and retreatment in teeth with apical periodontitis (AP) compared to teeth with AP and no sealer extrusion at the 1-year follow-up.

METHODS

In a retrospective case-control study conducted from September 2016 to September 2021, teeth presenting clinical and radiographic signs of AP prior to treatment were included. The study comprised 2 groups: AH Plus sealer extrusion group (n = 60): initial root canal treatment or nonsurgical retreatment with unintentional apical extrusion of AH Plus sealer; and no AH Plus sealer extrusion group (n = 60): underwent the same treatment types without sealer extrusion. Additional factors, including sex, age, tooth type, tooth location, and treatment type, were recorded as potential outcome predictors. At 1-year follow-up, teeth were evaluated clinically and radiographically, and outcomes were classified as favorable (healed/healing) or unfavorable (uncertain/non-healing). Statistical analyses, such as the χ2 test, logistic regression, and Mann-Whitney U test, were employed for data analysis.

RESULTS

A favorable outcome was observed in 88.4% and 85% of the cases of the AH Plus sealer extrusion and no AH Plus sealer extrusion groups, respectively. There was no statistically significant difference between the groups in terms of outcomes (P > .05) when analyzed categorically or ordinally. Of independent variables, nonsurgical retreatment showed lower healing of AP in both groups.

CONCLUSIONS

Unintentional AH Plus sealer extrusion did not affect the healing of AP. However, initial root canal treatment showed better healing of AP than nonsurgical retreatment in the presence of AH Plus sealer extrusion. The analyzed outcome predictors had no effect on treatment outcome.

Augmented Reality-Guided Apicoectomy Based on Maxillofacial CBCT Scans

Implementation of augmented reality (AR) image guidance systems using preoperative cone beam computed tomography (CBCT) scans in apicoectomies promises to help surgeons overcome iatrogenic complications associated with this procedure. This study aims to evaluate the intraoperative feasibility and usability of HoloLens 2, an established AR image guidance device, in the context of apicoectomies. Three experienced surgeons carried out four AR-guided apicoectomies each on human cadaver head specimens. Preparation and operating times of each procedure, as well as the subjective usability of HoloLens for AR image guidance in apicoectomies using the System Usability Scale (SUS), were measured. In total, twelve AR-guided apicoectomies on six human cadaver head specimens were performed (n = 12). The average preparation time amounted to 162 (±34) s. The surgical procedure itself took on average 9 (±2) min. There was no statistically significant difference between the three surgeons. Quantification of the usability of HoloLens revealed a mean SUS score of 80.4 (±6.8), indicating an "excellent" usability level. In conclusion, this study implies the suitability, practicality, and simplicity of AR image guidance systems such as the HoloLens in apicoectomies and advocates their routine implementation.

Three-Dimensional Printed Tooth Model with Root Canal Ledge: A Novel Educational Tool for Endodontic Training

Ledge formation presents a significant challenge in endodontic treatment. Yet, there is still a lack of educational tooth models for hands-on practice. This study aimed to create and evaluate a tooth model for ledge management practice. A natural tooth with curved roots was collected for scientific use under ethics committee approval. Following initial root canal preparation, the tooth was scanned using micro-computed tomography (μCT) and 3D reconstructed. A K-file, created via computer-aided design (CAD), was partly inserted into the root canal wall of the 3D reconstructed tooth. By subtracting the K-file from the tooth, a tooth model with a root canal ledge was produced. The model was then 3D printed for a hands-on workshop. An eight-item Likert-scale questionnaire was administered to 20 postgraduate students and 10 endodontists to assess the model's quality and training effectiveness. In addition, the success rate of bypassing and correcting the root canal ledge was documented. The feedback from both the students and experts was positive, and the results of the Mann-Whitney U test indicated no statistically significant differences found between the two groups (p > 0.05). The success rate of the students and the experts was 85% and 100%, respectively. In future applications, this novel tooth model is expected to address the existing gap in endodontic education and provide benefits for dental practitioners.

Clinical outcomes of non-surgical root canal obturations using NeoMTA: A retrospective series of case reports

NeoMTA is a commercially available tricalcium silicate-based cement intended for contact with pulp and periradicular tissues. The purpose of this study was to retrospectively evaluate the outcomes of non-surgical root canal treatments with NeoMTA obturations. Patients were treated in a private endodontic practice between 2015 and 2018. All cases, including initial treatments and retreatments, were either fully obturated with NeoMTA, or using gutta-percha with NeoMTA as an endodontic sealer. Outcomes were assessed using follow-up examination data with digital periapical radiographs with a minimum of a 1-year recall. Teeth were classified based on the clinical examination as: healed/healing (success), or non-healed (failure). 265 teeth were included with an average follow-up time of 1.3 years. The overall success rate was 91.7%. Only the presence of a pre-operative periapical radiolucency was found to significantly affect success. Comparison of obturation techniques demonstrated no effect on outcomes. NeoMTA is suitable for endodontic obturation.

Are comorbidities associated with the cytokine/chemokine profile of persistent apical periodontitis?

OBJECTIVES

This study aimed to identify disease-related markers in persistent apical periodontitis (PAP) biopsies and examine whether these were associated with comorbidities like rheumatoid arthritis (RA) and cardiovascular diseases (CVD).

MATERIALS AND METHOD

The levels of the cytokines/chemokines GM-CSF, IFN-γ, IL-2, IL-6, IL-9, IL-10, IL-13, IL-15, IL-17E/IL-25, IL-21, IL-23, IL-27, IL-28A/IFN -λ2, IL-33, MIP-3α/CCL20, and TNF-α were determined in lesions from patients with PAP (n = 20) and compared to healthy bone samples (n = 20).

RESULTS

We identified eleven cytokines to be differently expressed, and among them, IL-2, IL-6, IL-17E, IL-21, and IL-27 appeared to drive the discrepancy between the disease and healthy groups. The levels of T follicular helper (Tfh) cell promoting cytokines (IL-21, IL-6, IL-27) were enhanced while T helper (Th) 1 cell promoting cytokine (IL-2), Th2 cell promoting cytokine (IL-13), and Th17 cell promoting cytokine (IL-17E) were reduced in the PAP group. The data also indicate that Tfh cell differentiation (IL-21), along with Th1 (GM-CSF, IFNγ), Th2 (IL-13), and Th17 (GM-CSF) cell differentiation, might be increased in the subpopulation of patients suffering from RA, whereas no differences were found in patients with CVD.

CONCLUSIONS

Levels of cytokines/chemokines in PAP were identified, and cluster analyzes indicated that these markers may be associated with the differentiation of different T cell populations. Patients with PAP and RA comorbidities showed elevated levels of markers reinforcing this association.

CLINICAL RELEVANCE

Molecular analyses of PAP may result in identification of prognostic markers.

Biological considerations of dental materials as orifice barriers for restoring root-filled teeth

There is ample published literature regarding the technical aspects of restoring root-filled teeth, but little concerning the biological impacts, consequences, and criteria for the selection of direct restorative materials following endodontic treatment. The provision of an effective coronal seal in addition to a sound root filling is known to be important in the prevention of root canal infection. This review seeks to explore the evidence concerning the selection of dental materials in the restoration of root-filled teeth, specifically with a close examination of the properties of commonly used materials as orifice barriers. © 2023 Australian Dental Association.

A Retrospective Study on Endodontic Treatment Outcomes in Patients with Special Needs

INTRODUCTION

Outcomes of endodontic treatment in patients with special needs are not fully understood, leading to reluctance in performing endodontic treatment.

METHODS

This retrospective cohort study evaluated the periapical healing and tooth survival in patients with special needs who had permanent teeth endodontically treated in a hospital setting between 1998 to 2019. Data characterization was performed using univariate analyses. Logistic and Cox regression analyses (P<0.05) were performed to identify the odds ratio (OR) and hazard ratio (HR) of the potential prognostic factors, respectively. These predictors were chosen from previous outcome studies in the general population and patients with special needs.

RESULTS

61 patients (108 teeth) met the inclusion criteria. Most common treatment modality was initial therapy with 81.5% of cases being managed without a need for general anesthesia. Healing rate for initial endodontic treatment was 89.9% and was affected by no restoration at follow-up (OR=0.15, 95%CI:0.12, 0.71, P=0.02). After a mean follow up of 79.36±59.6 months, the survival rate was 73% and was correlated with gender (HR for males = 0.3; 95% CI, 0.1-0.6; P <0.05) and age (HR for patients >45 years = 3.7; 95% CI, 1.7-8.2; P<0.05). The most common reason for tooth extraction was unrestorable tooth fracture.

CONCLUSIONS

Endodontic therapy without a need for general anesthesia is a viable treatment option for patients with special needs. If the overall patient condition permits, then treatment can be administered by community dentists rather than waiting for a patient to be seen in a hospital setting.

Incidence of Endodontic Failure Cases in the Department of Conservative Dentistry and Endodontics, DY Patil School of Dentistry, Navi Mumbai

INTRODUCTION

 Endodontic and restorative treatment goal is to restore occlusion and normal function of a tooth and provide stability to the dental arch. Root canal bacterial infection and apical periodontitis profoundly impact the management and outcome of endodontic treatments. The crucial goal of nonsurgical root canal therapy (NSRCT) is the mechanical removal of infected tissues and the chemical killing of bacteria. The present study assessed the outcomes and factors associated with the failure of primary endodontic treatment.

METHODS

 A total of 250 teeth from 219 patients (104 male and 146 female) were examined in the Conservative Dentistry and Endodontics department, who reported symptomatic root canal-treated teeth. Data through clinical examination and radiographic examination was recorded on a proforma designed for the study of each patient regarding endodontic failure.

RESULTS

 According to the type of tooth maximum number of teeth that were reported with failure are the molars (67.6%), followed by premolar (14.0%), incisor (12.8%), and lastly, canines (5.6%). Based on the location of affected teeth, the maximum teeth that presented with failed root canal treatment were from mandibular posteriors (51.2%), followed by maxillary posteriors (31.60%), maxillary anterior (13.2%), mandibular anterior (4.0%).

CONCLUSION

 Endodontic failures were mostly found in underfilled root canals and poorly sealed post-endodontic coronal restoration and strong association with peri-apical radiolucency.

A randomized controlled clinical trial of pulpotomy vs root canal therapy in mature teeth with irreversible pulpitis: Outcome, quality of life, and patients' satisfaction

INTRODUCTION

Vital pulp therapy (VPT)is increasingly practiced as an alternative treatment to root canal therapy (RCT) in teeth with carious pulp exposure. The aim of this study was to compare the outcome, quality of life and patient satisfaction after full pulpotomy and RCT in mature teeth with irrevrsible pulpitis.

METHODS

Sixty mature permanent molar teeth with carious pulp exposure and a diagnosis of irreversible pulpitis were randomly divided into 2 groups (n=30). The first group was treated with full pulpotomy using Biodentine and the second group was treated with RCT. Pain level was recorded preoperatively and at 1, 2, 3, 5 and 7 days. Clinical and radiographic assessment was done at 6 and 12 months follow up, one case in each group did not attend. Based on the Oral Health Impact Profile questionnaire (OHIP-17) and 7 semantic differential scales, quality of life (QOL) and patients' satisfaction were evaluated and compared statistically.

RESULTS

Pulpotomy and RCT had comparable success rates (27/29, 93%). Pain levels at day 1 after pulpotomy were significantly lower than after RCT (p=0.037), less patients required analgesics (p=0.028), and pulpotomy provided pain relief in a shorter time compared to RCT. Both treatments improved the OHIP QOL of patients without significant differences (60.29, 64.1% at 1 year). Patients' satisfaction with pulpotomy was higher than RCT in terms of the time involved, intraoperative pain, pleasantness, and cost (p <0.05).

CONCLUSIONS

Full pulpotomy could be an alternative treatment to RCT in mature teeth with carious pulp exposure and symptomatic irreversible pulpitis, based on the clinical, radiographic success rates and patients' satisfaction.

The Effect of General Anesthesia on the Outcome of Root Canal Treatment in Pediatric Patients—A Retrospective Cohort Study

This study aimed to evaluate the effect of general anesthesia (GA) on the 1-year outcome of Root Canal Treatment (RCT) performed in pediatric patients and to compare it to the outcome of RCT in pediatric patients without GA. Patients admitted for RCT in permanent dentition in a public hospital, dated 2015 to 2020, age 8–15 with a minimum of one year follow-up period, were included in the study. The sample consisted of 326 teeth from 269 patients treated by a single operator, with a recall rate of 81%. Overall, 124 teeth were treated under GA and 142 teeth were without GA. The mean follow-up time was 31.5 months. Data underwent statistical analysis and the significance threshold was set for p < 0.05. Of the total cases, 90% showed favorable outcomes. A significantly higher favorable outcome was seen in the GA group than in the non-GA group (98% and 85%, respectively, p < 0.001). The outcome was significantly affected by the type and quality of the coronal restoration, degree of root development, and lesion size (p < 0.05). According to the current study, in uncooperative pediatric patients, a more favorable outcome of root canal treatment can be obtained under GA than LA if the procedure is carried out with immediate restoration.

Factors that affect the outcomes of root canal treatment and retreatment-A reframing of the principles

This paper undertakes a broad and comprehensive synthesis of relevant clinical, biological, biomechanical, technical and healthcare services data to understand the factors affecting outcomes of periapical healing after root canal (re)treatment. The medical and dental evidence-based era (1980-present) is contextualized with the earlier evidence drive in endodontics (1911-1940) triggered by the focal infection era. The current evidence-based approach has a sharper focus on evidence quality and derivation of practice guidelines. Contrary views question whether guideline-driven, or expertise-development-driven endeavours would best serve outcome improvement in society. The endodontic discipline functions in a broad healthcare framework and sustains industrial, economic and trend pressures that may be deemed to influence outcomes. The nature of root canal treatment and the challenges in determining the factors that affect its outcomes is discussed. The factors potentially affecting periapical healing after root canal treatment are classified into pre-operative, intra-operative and postoperative groups. These categories subsume multiple elements with interactive influences, creating a complex picture, further confounded by some apparently surprising, counter-intuitive and contradictory findings. The technical versus biological conundrum in root canal treatment continues to cause cognitive dissonance. However, due reflection and cross-discipline-synthesis resolve the apparent data conflicts into a very simple, consistent and plausible picture of how root canal treatment works and the key factors that affect periapical healing. Root canal retreatment is considered mainly in the context of its differences from primary treatment as the majority of factors influencing outcomes are common to both. The exceptional difference is that retreatments have a proportionately reduced probability of healing by virtue of compromised apical root canal ramification access or modified host/infection interactions. Root canal (re)treatment outcomes are dominantly influenced by the nature of prior dynamic host/infection interaction (pre-operative patient factors) and how the direction of this dynamic is influenced by two factors: (1) the active efficacy of the operators' root canal treatment protocol to sustain a microbial ecological shift (intra-operative treatment factors) and dampen periapical inflammation; and (2) the passive ability of the functional tooth (and its restoration margin) to maintain its integrity to resist infection reversal (postoperative restorative factors).

DENTAL PATIENT-REPORTED OUTCOMES IN ENDODONTICS - A NARRATIVE REVIEW

Recently in oral health care settings, the focus of assessing treatment outcomes has shifted from the perspective of the clinician towards that of the patient. Endodontology is a specialty of dentistry concerned with the prevention and treatment of pulp and periapical diseases. Research in endodontology and its associated treatment outcomes have focused mainly on clinician-reported outcomes (CROs) and not dental patient-reported outcomes (dPROs). As a result, there is a need to emphasize the importance and relevance of dPROs to researchers and clinicians. The aim of this review is to present an overview of dPROs and dPROMs within endodontics in an attempt to create a better understanding of the patient experience, highlight the need to place the patient at the center of treatment, enhance patient care and encourage more research into dPROs. The key dPROs following endodontic treatment include pain, tenderness, tooth function, need for further intervention, adverse effects (exacerbation of symptoms, tooth discoloration) and Oral Health-Related Quality of Life. dPROs are important following endodontic treatment because they assist clinicians and patients when they discuss and select the most appropriate management options, help clinicians make decisions on pre-operative assessment, prevention and treatment, and improve the methodology and design of future clinical studies. Clinicians and researchers in endodontology should prioritize patient welfare and undertake routine analyses of dPROs using appropriate and robust measures. Due to the lack of agreement over the reporting and definition of endodontic treatment outcomes, a comprehensive project to define a ``Core Outcome Set for Endodontic Treatment Methods (COSET)'' is currently ongoing. In the future, a new and exclusive assessment tool should be developed to reflect the viewpoints of patients receiving endodontic treatment more accurately.

Outcome of selective root canal retreatment-A retrospective study

AIM

Selective root canal retreatment is when the treatment is limited to root(s) with radiographic evidence of periapical pathosis. The goals of this retrospective study were as follows: (i) evaluate the clinical and radiographic (periapical radiographs [PR] or cone-beam computerized tomographs [CBCT]) outcome of selective root canal retreatment after ≥12 months follow-up; (ii) evaluate the periapical status of the unretreated roots; and (iii) assess tooth survival.

METHODOLOGY

A retrospective study (January 2018 to April 2021) was conducted to identify permanent multirooted teeth that underwent selective root canal retreatment. Clinical records, PR and CBCT were examined to ascertain variables of interest. Outcomes (per root and per tooth) were classified into 'favourable' or 'unfavourable' using well-established clinical and radiographic healing criteria. Treatment outcomes for the whole tooth and per root were compared as well as bivariate associations between the treatment outcome of the retreated roots and the treatment-related parameters (quality of root filling, sealer extrusion, iatrogenic mishaps and type of restoration) were analysed using Fisher's exact test (α = .05). Survival was recorded in months.

RESULTS

A total of 75 teeth (195 roots) in 75 subjects were available for outcome analysis. The favourable outcome per tooth was 86.7%. At follow-up, 92.6% of the retreated roots had a favourable outcome. From the unretreated roots, 3.5% showed radiographic signs of an emerging periapical lesion. No statistical difference was shown between the outcomes per root and per tooth between both groups. None of the treatment-related parameters had a direct influence on the outcome of the retreated roots. The survival rate at 12-48 months after retreatment was 91.5%.

CONCLUSIONS

Selective root canal retreatment is associated with a favourable outcome in a majority of cases. Unretreated roots rarely developed radiographic signs of a new periapical lesion at follow-up. Future high-quality clinical trials with larger sample sizes and longer follow-up periods are required to confirm these findings.

Micro-computed tomographic evaluation of endodontic ledge position in relation to canal curvatures

Background

Endodontic ledge (EL) formation is the most common complication of endodontic treatment. Although various etiological factors have been identified, canal curvature is the most significant variable correlated with EL formation. The aim of this micro-computed tomographic (micro-CT) study was to evaluate EL position in the mesial canals of the lower molars in relation to the degree of canal curvature.

Methods

Forty intact mandibular first molars with independent mesial canals with 20°–40° primary mesio-distal curvature, 10°–30° buccal-lingual canal curvature and 4 < r ≤ 8 mm main curvature radius were selected. Working length was measured with a K-File #10 and a high resolution pre-operative micro-CT analysis was performed. Ledges were created at the point of maximum canal curvature using stainless steel K-Files #30–35, alternating irrigation with 5% NaOCl and 10% EDTA. A post-operative high-resolution micro-CT analysis was then completed. Pre- and post-operative images were analyzed. The angle (α) formed between the vector passing through the geometric center of the EL and the center of the original canal lumen and the line joining the centers of the mesio-buccal and mesio-lingual canal orifices was calculated, and a descriptive statistical analysis was achieved. The α angle values were analyzed in relation to canal curvature using Kruskal-Wallis and post hoc Dunn’s tests. The level of significance was set at P < 0.05.

Results

The α angles appeared inversely proportional to canal curvatures in the buccal-lingual and mesio-distal projections. The mean α angle was 36.4° (standard deviation 10.64; 95% confidence interval 34.1–40.9).

Conclusion

Within the limitations of this study, endodontic ledges develop in the opposite direction to the three-dimensional canal curvature and their position is influenced by the degree of curvature. Clinically, the α angle values may be related to the recommended direction to manage endodontic ledges.

Clinical outcome of bioceramic sealer iRoot SP extrusion in root canal treatment: a retrospective analysis

Background

During the obturation procedure, sealer extrusion occurs in some cases. iRoot SP is a kind of bioceramic sealer with superior physicochemical and biological properties. This article reports the outcome of iRoot SP extrusion in root canal treatment and the potential factors associated with the outcome.

Methods

Ninety-nine patients and one hundred and eighty-five teeth treated between 2014 and 2020 were included in this retrospective study. All of the cases were filled with a single-cone technique and the iRoot SP sealer. The minimum follow-up visit period was 1 year. The outcome was evaluated by clinical examination and radiographic examination at recall and was classified as healed, healing (success), or not healed (failure).

Results

The overall success rate of all teeth was 96.8%. The success rate of adequately filled teeth was 97.3%, while that of iRoot SP extrusion was 95.8%; the difference was not statistically significant. Factors such as gender, age, tooth position, follow-up visit period, size of periapical lesion, treatment type and extruding sealer amount had no influence on the outcome of iRoot SP extruded teeth.

Conclusions

The results suggested that iRoot SP extrusion has no adverse effect on the outcome of root canal treatment, which may contribute to the endodontic treatment.

Radiographic predictors for MRONJ in oncologic patients undergoing tooth extraction

Tooth extraction is a risk factor for the development of osteonecrosis of the jaw following treatment with antiresorptive drugs (ARDs), but not all extraction sites develop this pathology. Therefore, we aimed to identify local radiographic predictors of Medication-Related Osteonecrosis of the Jaw (MRONJ) in panoramic images of oncologic patients undergoing tooth extraction. Based on a retrospective longitudinal cohort study design, patients were included if undergoing one or more tooth extraction, with at least one administration of ARDs, and presence of pre- and post-operative panoramic radiographs. After data collection, blinded and independent observations were performed. Eleven distinct imaging-related parameters were assessed preoperatively and five postoperatively, at each extraction site. A case-control and subgroup analysis assessing MRONJ development was performed. Significance level is set to 0.05 (5%). A total of 77 oncologic patients were selected, undergoing 218 tooth extractions, from which 63 teeth (29%) in 39 patients (51%) developed MRONJ. Results showed that patients developed significantly more MRONJ with longer ARD treatment (p = 0.057), teeth with absent and incomplete endodontic fillings with caries, widened periodontal ligament space and/or periapical lesions (p = 0.005), and sclerotic and heterogenous bone patterns (p = 0.005). In conclusion, tooth extraction sites presenting with infections and bone sclerosis are at higher risk to develop MRONJ.

Impact of access cavity cleaning on the seal of postendodontic composite restorations in vitro

AIM

To investigate the influence of cavity cleaning and conditioning on marginal integrity of directly placed postendodontic composite class-I-restorations in vitro.

METHODOLOGY

168 fully intact teeth without caries or fillings received preendodontic composite restorations (class-II) after their extraction. Occlusal endodontic access-cavities were prepared, root-canals were instrumented and filled with guttapercha and an epoxy-resin based sealer. Prior to postendodontic class-I-restoration, access cavities were completely contaminated with sealer, cleaned with alcohol and pretreated as follows: Cleaner only (alcohol), glycine-polishing, Al₂ O₃ -sandblasting, carbide bur (immediate as well as delayed restoration). A positive control (not contaminated with sealer and adhesive used) and negative control (cleaner used but no adhesive) were established. Half of the teeth from each group were subjected to thermocycling and mechanical loading (TCML). Marginal integrity of postendodontic restoration was evaluated in oro-vestibular or mesio-distal sections after AgNO₃ -dye-penetration (DP) by standardized photomacroscopic imaging and expressed in percent of margin length along all segments and separately for enamel, dentine and composite, respectively. Results were analyzed non-parametrically (α=0.05).

RESULTS

No restorations or teeth fractured or debonded completely. Without TCML, the median DP of all segments was significantly higher for the negative control compared to all other groups in oro-vestibular cutting direction (53%; P=0.002) and in mesio-distal cutting direction (51%; P≤0.041). The other groups without TCML revealed 16-24% DP (oro-vestibular) and 12-24% DP (mesio-distal). With TCML, the median DP in oro-vestibular cutting direction for all segments ranged between 48-62% for all groups, a significant difference was only observed between glycine-polishing and carbide bur (P=0.041). In mesio-distal cutting direction, the median DP in negative control was 69% with TCML and significantly higher compared to all other groups (P=0.002). For all other groups, the median DP of all segments ranged between 28% and 40% with TCML without significant differences. Error rates method (k=7) revealed a significant influence of TCML in general on penetration of all segments in both, oro-vestibular and mesio-distal cutting directions.

CONCLUSION

Additional access cavity pretreatment after alcohol cleaning did not improve the marginal integrity of postendodontic composite restorations. Thorough cleaning of the access cavity with alcohol seems to assure an acceptable marginal integrity to the tooth and restorative composite.

The objectives and instructional design of undergraduate endodontic program: multicenter cross-sectional study in Saudi Arabia

BACKGROUND

Identify the objectives and the instructional design of undergraduate endodontics in dental schools in Saudi Arabia.

METHODS

The online questionnaire was developed from an original survey conducted in the United Kingdom. The questionnaire was modified for purpose of the study and the region of interest. Then it was directed and emailed to the undergraduate endodontic program directors in twenty-six dental schools in Saudi Arabia. The results were analyzed using descriptive statistics and the Chi-square and Fisher's exact tests.

RESULTS

The response rate was 96.15%. The number of credit hours for preclinical endodontic courses was up to four credit hours (84%). Students were clinically trained to do vital pulp therapies (92%), root canal treatment (100%), and root canal retreatment (68%). The majority of dental schools define the minimum clinical requirements (92%). Practical and clinical competency exams were used to evaluate students' performance (92% and 84% respectively). The students were trained to treat cases of minimal (52%) to moderate complexity (48%). Endodontic treatment consent and difficulty assessment form were used by 32% and 60% of dental schools respectively. There was no significant difference in the instructional design between public and private dental schools (P > 0.05).

CONCLUSION

The endodontic undergraduate objectives were to graduate competent clinicians who acquired basic science of endodontics and who know their limitations as it is necessary for a safe general dental practice. The use of endodontic treatment consent and case difficulty assessment should be wisely considered in clinical training.

Clinical Potential of Dental Pulp Stem Cells in Pulp Regeneration: Current Endodontic Progress and Future Perspectives

Dental caries is a common disease that not only destroys the rigid structure of the teeth but also causes pulp necrosis in severe cases. Once pulp necrosis has occurred, the most common treatment is to remove the damaged pulp tissue, leading to a loss of tooth vitality and increased tooth fragility. Dental pulp stem cells (DPSCs) isolated from pulp tissue exhibit mesenchymal stem cell-like characteristics and are considered ideal candidates for regenerating damaged dental pulp tissue owing to their multipotency, high proliferation rate, and viability after cryopreservation. Importantly, DPSCs do not elicit an allogeneic immune response because they are non-immunogenic and exhibit potent immunosuppressive properties. Here, we provide an up-to-date review of the clinical applicability and potential of DPSCs, as well as emerging trends in the regeneration of damaged pulp tissue. In addition, we suggest the possibility of using DPSCs as a resource for allogeneic transplantation and provide a perspective for their clinical application in pulp regeneration.

Effect of Different Downward Loads on Canal Centering Ability, Vertical Force, and Torque Generation during Nickel-Titanium Rotary Instrumentation

This study aimed to examine how downward loads influence the torque/force and shaping outcome of ProTaper NEXT (PTN) rotary instrumentation. PTN X1, X2, and X3 were used to prepare J-shaped resin canals employing a load-controlled automated instrumentation and torque/force measuring device. Depending on the torque values, the handpiece was programmed to move as follows: up and down; downward at a preset downward load of 1 N, 2 N or 3 N (Group 1N, 2N, and 3N, respectively; each n = 10); or upward. The torque/force values and instrumentation time were recorded, and the canal centering ratio was calculated. The results were analyzed using a two-way or one-way analysis of variance and the Tukey test (α = 0.05). At the apex level, Group 3N exhibited the least canal deviation among the three groups (p < 0.05). The downward force was Group 3N > Group 2N > Group 1N (p < 0.05). The upward force, representing the screw-in force, was Group 3N > Group 1N (p < 0.05). The total instrumentation time was Group 1N > Group 3N (p < 0.05). In conclusion, increasing the downward load during PTN rotary instrumentation improved the canal centering ability, reduced the instrumentation time, and increased the upward force.

Outcomes of Primary Root Canal Therapy: An updated Systematic Review of Longitudinal Clinical Studies Published between 2003 and 2020

Background

A comprehensive effort to evaluate outcomes of primary root canal therapy (RCT) between 1966 and 2002 was published by Ng et al. (2007, International Endodontic Journal, 40, 921; 2008, International Endodontic Journal, 41, 6). Changes in endodontic materials and treatment methods warrant an updated analysis of outcomes.

Objectives

This study aimed to (1) quantify the success rates of primary RCT published between 2003 and 2020; and (2) investigate the influence of some characteristics known/suspected to be associated with treatment outcomes.

Methods

An electronic search was performed in the following databases (01‐01‐2003 to 12‐31‐2020): Pubmed, Embase, CINHAL, Cochrane and Web of Science. Included study designs were longitudinal clinical studies (randomized control trials, cohort studies, retrospective observational studies). Studies with at least twelve‐months of post‐operative review and success rates based on clinical and radiographic criteria were analysed. The terms ‘strict’ (complete resolution of periapical lesion) or ‘loose’ (reduction in size of existing periapical lesion) were used to describe the outcome criteria. Weighted, pooled success rates were calculated. Random effects meta‐regression models were used to investigate potential sources of statistical heterogeneity. The Grading of Recommendations, Assessment, Development and Evaluation (GRADE) approach was used to evaluate for quality assessment of the included studies.

Results

Forty‐two studies were included in the review. Meta‐analyses showed that the weighted pooled success rates were estimated to be 92.6% (95% CI: 90.5%–94.8%) under ‘loose criteria’ and 82.0% (95% CI: 79.3%–84.8%) under ‘strict’ criteria. The most significant areas of study heterogeneity were year of publication and qualification of operator. The majority (64.29%) of studies were considered to be of low quality of evidence.

Discussion

Biological factors continue to have the most significant impact on RCT outcomes. The technological method of instrumentation had no significant effect. The quality of evidence was based primarily on study design and only randomized control trials were considered to be ‘high’ quality of evidence.

Conclusions

The reported success rates show improvement over time. Weighted success rates for studies with a minimum of four‐years follow‐up had better outcomes, compared to those with less than four years, when ‘strict criteria’ were used.

Registration

PROSPERO database (CRD42021226311).

Clinical Efficacy of Sealer-based Obturation Using Calcium Silicate Sealers: A Randomized Clinical Trial

INTRODUCTION

This randomized controlled clinical trial compared the clinical efficacy and outcome of a sealer-based obturation technique (SBO) with calcium silicate sealers and a continuous wave of condensation technique (CWC) with a resin-based sealer.

METHODS

Root canals were prepared using rotary instruments and 2.5% sodium hypochlorite. At the next visit, patients were enrolled and randomly assigned into 2 groups on the basis of the obturation protocol: CWC with AH Plus sealer and SBO with Endoseal TCS. Patients were assessed for the level of postoperative pain using a numeric rating scale. The quality of root canal obturation was evaluated in terms of the sealer extrusion, root-filling voids, and level of root filling. The participants were recalled after at least 6 months. Healing of the teeth was determined as a decrease in Periapical Index score and resolution of symptoms. The results were statistically compared by using the χ² test or Fisher exact test, followed by multivariate analysis with logistic regression.

RESULTS

A total of 74 teeth were included in the analysis (79% recalls), and the mean follow-up period was 17 months (6-29 months). Two groups expressed identical distribution of postoperative pain (P = .973) and similar quality of root canal obturation. The total success rates were 93.2% (CWC 92.3%, SBO 94.3%) by loose criteria and 60.8% (CWC 51.3%, SBO 71.4%) by strict criteria, with no significant differences between the 2 groups. The success rate by loose criteria in teeth with sealer extrusion was significantly lower than those in teeth without sealer extrusion (P = .049).

CONCLUSIONS

SBO using an Endoseal TCS could be a possible alternative to CWC using AH Plus. Sealer extrusion and postoperative pain were found to negatively impact prognosis of the endodontic treatment.

A Scoping Review of Four Decades of Outcomes in Nonsurgical Root Canal Treatment, Nonsurgical Retreatment, and Apexification Studies: Part 3-A Proposed Framework for Standardized Data Collection and Reporting of Endodontic Outcome Studies

INTRODUCTION

Despite initiatives to standardize and improve reporting of rapidly growing endodontic outcome research studies, issues related to missing and ambiguous information are still of great concern. In this article, we propose a framework for standardized data collection and a compiled checklist for reporting of various study designs on endodontic outcome.

METHODS

A comprehensive search was carried out to locate randomized controlled trials, cohorts, case-control studies, or case series of >100 patients that reported on endodontic outcomes. We reviewed these articles to develop a Data Collection Template and compiled a checklist for reporting of future endodontic outcome research.

RESULTS

Out of 354 eligible articles previously reported in our scoping review on endodontic outcome studies, 109 articles were selected and screened for study variables or levels of categorization. Our complied Data Collection Template was developed in 19 domains to highlight important demographic, preoperative, intraoperative, and postoperative variables. Because of the specific needs for endodontic outcome literature, we also proposed a compiled checklist (consisting of 4 main domains) to facilitate the reporting of various study designs on endodontic outcome studies. This checklist included simple descriptions of the required items and examples on reporting from published endodontic studies.

CONCLUSIONS

By facilitating the collection and reporting of relevant research data by investigators in private practice and academia, we hope that the proposed Data Collection Template and reporting guideline can highlight the importance of standardization among clinicians and researchers while producing valid scientific information that will support evidence-based treatment decisions.

A Comparative Analysis of the Piezoelectric Ultrasonic Appliance and Trephine Bur for Apical Location: An In Vitro Study

To compare and contrast the accuracy of piezoelectric ultrasonic insert (PUI) and trephine bur (TB) osteotomy site preparation techniques for apical location. (1) Material and methods: A total of 138 osteotomy site preparations were randomly distributed into one of two study groups. Group A: TB technique (n = 69) and B: PUI technique (n = 69). A preoperative cone-beam computed tomography scan and an intraoral scan were performed and uploaded to implant-planning software to plan the virtual osteotomy site preparations for apical location. Subsequently, the osteotomy site preparations were performed in the experimental models with both osteotomy site preparation techniques and a postoperative CBCT scan was performed and uploaded into the implant-planning software and matched with the virtually planned osteotomy site preparations to measure the deviation angle and horizontal deviation as captured at the coronal entry point and apical end-point between osteotomy site preparations using Student’s t-test statistical analysis. (2) Results: The paired t-test found statistically significant differences at the coronal entry-point deviations (p = 0.0104) and apical end-point deviations (p = 0.0104) between the TB and PUI study groups; however, no statistically significant differences were found in the angular deviations (p = 0.309) between the trephine bur and piezoelectric ultrasonic insert study groups. (3) Conclusions: The results showed that the TB is more accurate than the PUI for apical location.

Micro CT pilot evaluation of removability of two endodontic sealers

PURPOSE

This study compared the removability of AH Plus and EndoSequence BC sealers using in vitro micro-computed tomography.

METHODS

Ten single-canal, extracted human teeth were cleaned and shaped with ProTaper NEXT rotary files to size X5 (50/0.06) (Dentsply-Sirona). Canals were obturated with a single cone gutta-percha and either AH Plus (Dentsply-Sirona) (Group A) or EndoSequence BC (Brasseler) (Group B). ProTaper Universal Retreatment files (Dentsply-Sirona) were used to remove obturation materials after 90 days at 37^oC/100% humidity. Each tooth was scanned using micro-computed tomography (SkyScan 1272; Bruker) at an isotropic resolution of 6 μm from which the percent of material removed was calculated. Two-sample t-tests and one-way ANOVA were used for analysis.

RESULTS

The percent removal of materials in the coronal third was 92.9% ± 7.3% (Group A) and 93.2% ± 6.1% (Group B). Removal in the middle third was 94.9% ± 8.5% (Group A) and 96.5% ± 6.1% (Group B). Apical third removal was 76.2% ± 27.9% (Group A) and 70.1% ± 30.8% (Group B). No statistically significant differences were determined between the two sealers or among the sectional thirds within each group (P > 0.05).

CONCLUSION

AH Plus and EndoSequence BC sealers exhibit the same removability at all canal levels of 70% to 96%, with better removal coronally.

Restorative Treatment Patterns After Root Canal Obturation in Public Hospitals in Riyadh

AIM

This study aims to describe the pattern of coronal restoration use among different dental specialties after root canal obturation in two governmental hospitals in Riyadh.

MATERIALS AND METHODS

Electronic dental records at King Abdul-Aziz Medical City and University Dental Hospital were reviewed. Teeth that underwent initial root canal treatment on a permanent tooth for obturation using gutta-percha between April 2019 and June 2019 were included. The collected data included the type of material used for coronal restoration after RCT, immediate post-space preparation, cotton pellet placement, the clinical title and specialty of the treating physician, and the center where treatment was performed. Excel was used for data collection. IBM SPSS was used for descriptive and interferential analyses.

RESULTS

A total of 763 patients were included in the study, in which the double seal technique was used in 56% of the patients, followed by Cavit, which was used in approximately 17% of the patients. Post space was prepared immediately after root canal treatment in 49 patients, and only 17 teeth received the final post, whereas post space was temporized for the rest of the prepared teeth and received the final post at the following visits. Significant relations were found between the type of material used and the clinical title of the treating physician and between the material of choice and the specialty of the dentist. The double seal was the technique of choice among endodontists and restorative dentists, whereas advanced general dentists frequently used Cavit. The least used materials were IRM, amalgam, and Ketac Silver.

CONCLUSION

The double seal technique was found to be the most commonly used method to achieve a coronal seal, followed by Cavit. Other materials used after RCT, in sequential order based on the frequency of use, were GIC, temporary crowns, resin composite, RMGIC, prefabricated post with composite buildup, IRM, amalgam, and Ketac Silver.

The impact of an enhanced infection control protocol on molar root canal treatment outcome - a randomized clinical trial

AIM

To evaluate the effect of an enhanced infection control protocol on root canal treatment outcomes and on microbial load within root canals after chemomechanical preparation.

METHODOLOGY

A total of 144 molar teeth from 139 healthy patients receiving primary root canal treatment were block randomized to a standard protocol (StP) or an enhanced infection control protocol (EnP). Both treatment arms adhered to current best practice recommendations, while the EnP comprised additional steps that included replacing rubber dams, gloves, files, all instruments and surface barriers at the time of canal filling to reduce the chances of iatrogenic contamination. Patients and radiographic examiners were blinded to the protocol used. Intracanal microbial samples were taken at baseline (S1) and after completion of chemomechanical preparation (S2). Microbial 16S rDNA copy numbers were enumerated by quantitative polymerase chain reaction (qPCR). Cone beam computed tomography (CBCT) scans were taken before treatment and at one-year follow-up. The outcome was assessed clinically and radiographically using CBCT by logistic regression modelling.

RESULTS

At one-year follow-up, 115 teeth were analysed (54 in StP and 61 in EnP). The percentage of favourable outcomes assessed by CBCT was 85.2% in the EnP and 66.7% in the StP. The odds of 12-month success was three times higher in the EnP group compared with the StP group (OR=2.89; p=0.022, CI: 1.17 - 7.15). The median bacterial reads were reduced from 8.1×10³ in S1 samples to 3.5×10³ in the StP group and from 8.6×10³ to 1.3×10³ in the EnP group. The enhanced protocol significantly reduced bacterial counts in pre-canal filling samples when compared to the standard protocol (p=0.009).

CONCLUSIONS

The implementation of a facile, enhanced infection control protocol in primary root canal treatment resulted in less detectable bacterial DNA before canal filling and significantly more successful outcomes at one year.

Shot peening increases resistance to cyclic fatigue fracture of endodontic files

The objective of this study was to assess the resistance to fatigue fracture of conventional nickel–titanium files after undergoing shot peening. Forty NITIFLEX endodontic files, number 30, were divided into two groups; one was submitted to shot peening treatment and the other was not. All instruments were tested for fatigue fracture in simulated canals with a TRI-AUTO ZX endodontic motor. One file of each group was subjected to a residual stress analysis by XRD. Finally, the fractured surface was observed and elemental analysis performed by means of SEM and EDX. Roughness analysis was made by focal variation microscope. The shot peening group showed greater resistance to fatigue fracture; there was no difference in the length of the fractured fragments. XRD results showed the presence of residual compression stresses in the file submitted to shot peening, a decrease in the interplanar spacing, and an increase in the full-width-at-half-maximum and the microstrains. SEM and EDX showed a ductile fracture with zones of fatigue and an equiatomic ratio between the nickel and titanium. Surface roughness increased after the file was subjected to the shot peening procedure. In conclusion, shot peening increases the resistance to fatigue fracture due to the presence of residual compression stresses in files manufactured from a conventional nickel–titanium alloy.