A Scoping Review of 4 Decades of Outcomes in Nonsurgical Root Canal Treatment, Nonsurgical Retreatment, and Apexification Studies-Part 2: Outcome Measures

Effectiveness of microscope-assisted root canal treatment in permanent posterior teeth: A retrospective cohort study

OBJECTIVE

To evaluate the effect of microscope-assisted nonsurgical endodontic treatment on the clinical success rate in posterior teeth and to elucidate the interrelationship among various contributing factors.

MATERIALS AND METHODS

This retrospective cohort study included 337 teeth (from 301 patients) that underwent microscope-assisted root canal treatment (RCTx) and 298 teeth (from 256 patients) that underwent nonmicroscopic RCTx. All patients' electronic medical records and periapical radiographs were uniformly recorded. Strict and loose criteria were adopted to assess treatment success. Multiple logistic regression models were utilized to investigate the prognostic factors.

RESULTS

Significant differences were observed based on strict criteria regarding number of roots, number of canals, extra canal, swelling, sinus tract, palpation pain, deep and narrow pocket, apical lesion size, root resorption, secondary RCTx (2° RCTx), and periapical diagnosis (p < 0.05). Compared to nonapical lesion cases, the odds ratios of success in cases with preoperative apical lesions below 5 mm and at least 5 mm were 0.16 and 0.06 times, respectively (p < 0.001). The odds ratio of success for 2° RCTx was 0.35 times that of primary RCTx (1°RCTx) (p < 0.001). "Apical lesion size," "treatment type," and "RCTx with aid of microscope" were significantly correlated (p < 0.001) based on strict criteria. "RCTx with aid of microscope" was significantly correlated (p < 0.05) based on loose criteria.

CONCLUSION

Compared with traditional RCTx, microscope-assisted RCTx in posterior teeth resulted in a 2.9-fold and 3.2-fold increase in positive outcomes based on strict and loose criteria, respectively.

CLINICAL SIGNIFICANCE

Microscope-assisted RCTx may help manage difficult root canal referral cases and provide a better prognosis.

Biological and mechanical challenges in the endodontic treatment of immature teeth with pulp necrosis: insights based on a Series of Atypical Clinical Cases

Over the past two decades, dental pulp regeneration has become a major focus in endodontology. The currently applied clinical strategies are referred to as 'revitalisation' procedures. These biology-based treatment strategies aim at regenerating lost pulp tissues in necrotic teeth, in the absence or even more in the presence of periapical bone lesion, clinical signs and symptoms. Such approaches are generally - but not exclusively - used in immature teeth to promote root maturation, both in length and in thickness, ultimately to reduce their risk of fracture. A growing body of evidence has led to increased understanding and reliability of these treatment strategies, which are now considered as a valid alternative treatment option besides conventional ones, mainly the apical plug technique. However, all systematic reviews evaluating clinical outcomes concluded that there is a lack of robust long-term studies on the subject; most published cases of revitalisation having a relatively short-term follow-up, usually under 2 years. In this context, several major challenges remain to be addressed to better understand the promises and limitations of revitalisation procedures as compared to other treatment options, mainly the placement of an apical plug made of hydraulic calcium silicate cement. The purpose of this paper was therefore to identify some of the important remaining challenges related to such procedures, which can be broadly categorised into biological and mechanical ones, affecting treatment success and tooth survival. Meeting these challenges requires close collaboration between both researchers and clinicians, to establish guidelines, evaluate and understand treatment outcomes, and update guidelines accordingly. However, it is not always easy for researchers to understand the clinical reality faced by practitioners. In order to facilitate their mutual understanding, the aforementioned challenges were illustrated by providing clinical context through a series of atypical clinical cases with long-term follow-up (4-8 years).

Development of a Core Outcome Set in Endodontics (COS-ENDO): Part 5 - COS-ENDO for Studies of Apexification and Regenerative Endodontics in Permanent Teeth

INTRODUCTION

Methodological heterogeneity and reporting bias complicate interpreting endodontic outcomes. Supported by the American Association of Endodontists and its Foundation, this study developed the Core Outcome Set in Endodontics (COS-ENDO) to standardize reporting for studies of Nonsurgical Root Canal Treatment/Retreatment, Surgical Endodontics, Vital Pulp Therapy, Apexification, and Regenerative Endodontics. This article, the last in a 5-part series, focuses on COS-ENDO for Apexification and Regenerative Endodontics, while other parts address the remaining treatments.

METHODS

Outcomes were identified through scoping reviews and a web-based survey of American Association of Endodontists practicing members. In a 2-round Delphi survey, clinicians, patients, and researchers rated outcomes on a 9-point scale. Ratings were assessed against consensus criteria, and a virtual meeting finalized COS-ENDO.

RESULTS

Of the 97 invited participants to Round 1, 77 registered, and 73 (24 Academicians/Researchers, 26 Clinicians, and 23 Patients or their parents/caregivers) assessed 51 outcomes, with 18 excluded. The remaining outcomes-7 achieving consensus for inclusion and 26 lacking consensus-advanced to Round 2 for re-rating by 70 participants. This resulted in 14 outcome achieving consensus for inclusion, and 19 lacking consensus. In the final meeting, 16 participants finalized the COS-ENDO for Apexification and Regenerative Endodontics, including Tooth survival, Pain, Signs of infection, Radiographic evidence of periradicular healing, Continued root development, Success, Functional tooth, Need for further intervention, and Adverse events/Complications.

CONCLUSION

COS-ENDO is an important step in standardizing outcome reporting in endodontics, ensuring consistent reporting and enhancing research utility. Further efforts are needed to establish optimal measurement methods.

Development of a Core Outcome Set in Endodontics (COS-ENDO): Part 3 - COS-ENDO for Studies of Surgical Endodontics in Permanent Teeth

INTRODUCTION

Methodological heterogeneity and reporting bias complicate interpreting endodontic outcomes. Supported by the American Association of Endodontists and its Foundation, this study developed the Core Outcome Set in Endodontics (COS-ENDO) to standardize reporting for studies of nonsurgical root canal treatment/retreatment, surgical endodontics, vital pulp therapy, apexification, and regenerative endodontics. This article, part 3 of a 5-part series, focuses on COS-ENDO for surgical endodontics, while other parts address the remaining treatments.

METHODS

Outcomes were identified through a scoping review, a qualitative study with patients, and a web-based survey of American Association of Endodontists practicing members. In a 2-round Delphi survey, clinicians, patients, and researchers rated outcomes on a 9-point scale. Ratings were assessed against consensus criteria, and a virtual meeting finalized COS-ENDO.

RESULTS

Of the 97 invited participants to round 1, 77 registered, and 73 (24 academicians/researchers, 26 clinicians, and 23 patients or their parents/caregivers) assessed 46 outcomes, with 17 excluded. The remaining outcomes-7 achieving consensus for inclusion and 22 lacking consensus-advanced to round 2 for rerating by 70 participants. This resulted in 1 outcome achieving consensus for exclusion, 10 for inclusion, and 18 lacking consensus. In the final meeting, 16 participants finalized the COS-ENDO for surgical endodontics, including Tooth survival, Pain, Signs of infection, Radiographic evidence of periradicular healing, Success, Functional tooth, Need for further intervention, and Adverse events/Complications.

CONCLUSIONS

COS-ENDO is an important step in standardizing outcome reporting in endodontics, ensuring consistent reporting and enhancing research utility. Further efforts are needed to establish optimal measurement methods.

Development of a Core Outcome Set in Endodontics (COS-ENDO): Part 2 - COS-ENDO for Studies of Nonsurgical Root Canal Treatment and Retreatment in Permanent Teeth

INTRODUCTION

Methodological heterogeneity and reporting bias complicate interpreting endodontic outcomes. Supported by the American Association of Endodontists and its Foundation, this study developed the Core Outcome Set in Endodontics (COS-ENDO) to standardize reporting for studies of Nonsurgical Root Canal Treatment/Retreatment, Surgical Endodontics, Vital Pulp Therapy, Apexification, and Regenerative Endodontics. This article, Part 2 of a 5-part series, focuses on COS-ENDO for Nonsurgical Root Canal Treatment/Retreatment, while other parts address the remaining treatments.

METHODS

Outcomes were identified through scoping reviews, a qualitative study with patients, and a web-based survey of American Association of Endodontists practicing members. In a 2-round Delphi survey, clinicians, patients, and researchers rated outcomes on a 9-point scale. Ratings were assessed against consensus criteria, and a virtual meeting finalized COS-ENDO.

RESULTS

Of the 97 invited participants to Round 1, 77 registered, and 73 (24 Academicians/Researchers, 26 Clinicians, and 23 Patients (or their parents/caregivers)) assessed 39 outcomes, with 18 excluded. The remaining outcomes-7 achieving consensus for inclusion and 14 lacking consensus-advanced to Round 2 for re-rating by 70 participants. This resulted in 9 outcomes achieving consensus for inclusion, and 12 lacking consensus. In the final meeting, 16 participants finalized the COS-ENDO for Nonsurgical Root Canal Treatment/Retreatment, including Tooth survival, Pain, Signs of infection, Radiographic evidence of periradicular healing, Success, Functional tooth, Need for further intervention, and Adverse events/Complications.

CONCLUSIONS

COS-ENDO is an important step in standardizing outcome reporting in endodontics, ensuring consistent reporting and enhancing research utility. Further efforts are needed to establish optimal measurement methods.

Development of a Core Outcome Set in Endodontics (COS-ENDO): Part 1 - General Methods for Developing COS-ENDO for Studies of Nonsurgical Root Canal Treatment, Retreatment, Surgical Endodontics, Vital Pulp Therapy, Apexification, and Regenerative Endodontics in Permanent Teeth

INTRODUCTION

Methodological heterogeneity and reporting bias complicate interpreting endodontic outcomes. Supported by the American Association of Endodontists and its Foundation, this study developed the Core Outcome Set in Endodontics (COS-ENDO) to standardize reporting for studies of nonsurgical root canal treatment/retreatment, surgical endodontics, vital pulp therapy, apexification, and regenerative endodontics. This article, the first in a 5-part series, outlines the methods for developing COS-ENDO, with detailed findings for each treatment presented in subsequent parts.

METHODS

Outcomes were identified through scoping reviews, a qualitative study with patients, and a web-based survey of American Association of Endodontists practicing members. In a 2-round Delphi survey, clinicians, patients, and researchers rated outcomes on a 9-point scale. Ratings were assessed against consensus criteria, and a virtual meeting finalized COS-ENDO.

RESULTS

Of the 97 invited participants to round 1, 77 (79%) registered and 73 (95%) completed the survey, including 24 academicians/researchers, 26 clinicians, and 23 patients (or their caregivers/parents). They rated 64 outcomes, totaling 182 occurrences across treatments: 39 for nonsurgical root canal treatment/retreatment, 46 for surgical endodontics, 46 for vital pulp therapy, and 51 for apexification/regenerative endodontics. The outcomes that achieved consensus for inclusion and those lacking consensus (either for inclusion or exclusion) advanced to round 2 for rerating by 70 participants. During the final consensus meeting, 16 participants discussed the outcomes and finalized the COS-ENDO.

CONCLUSION

COS-ENDO is an important step toward standardizing outcome reporting in endodontics. Its implementation will ensure consistent reporting, enhancing research utility and evidence synthesis. Further efforts are needed to establish optimal measurement methods.

Development of a Core Outcome Set in Endodontics (COS-ENDO): Part 4 - COS-ENDO for Studies of Vital Pulp Therapy in Permanent Teeth

INTRODUCTION

Methodological heterogeneity and reporting bias complicate interpreting endodontic outcomes. Supported by the American Association of Endodontists and its Foundation, this study developed the Core Outcome Set for Endodontics (COS-ENDO) to standardize reporting for studies of Nonsurgical Root Canal Treatment/Retreatment, Surgical Endodontics, Vital Pulp Therapy, Apexification, and Regenerative Endodontics. This article, Part 4 of a 5-part series, focuses on COS-ENDO for Vital Pulp Therapy, while other parts address the remaining treatments.

METHODS

Outcomes were identified through a scoping review and a web-based survey of American Association of Endodontists practicing members. In a 2-round Delphi survey, clinicians, patients, and researchers rated outcomes on a 9-point scale. Ratings were assessed against consensus criteria, and a virtual meeting finalized COS-ENDO.

RESULTS

Of the 97 invited participants to Round 1, 77 registered, and 73 (24 Academicians/Researchers, 26 Clinicians, and 23 Patients or their parents/caregivers) assessed 46 outcomes, with 17 excluded. The remaining outcomes-4 achieving consensus for inclusion and 25 lacking consensus-advanced to Round 2 for re-rating by 70 participants. This resulted in 10 outcomes achieving consensus for inclusion, and 19 lacking consensus. In the final meeting, 16 participants finalized the COS-ENDO for Vital Pulp Therapy studies, including Tooth survival, Pain, Signs of infection, Radiographic evidence of maintained periradicular health, Continued root development, Success, Functional tooth, Need for further intervention, and Adverse events/Complications.

CONCLUSION

COS-ENDO is an important step in standardizing outcome reporting in endodontics, ensuring consistent reporting and enhancing research utility. Further efforts are needed to establish optimal measurement methods.

Patient-Centered Outcome Assessment of Static and Dynamic Navigation-Aided Endodontic Microsurgery: A Randomized Controlled Trial

INTRODUCTION

This study aimed to evaluate the quality of life (QoL) and analgesic use 1 week after surgery, as well as the surgical duration, associated with static navigation (SN) and dynamic navigation (DN)-aided endodontic microsurgery (EMS).

METHODS

Sixty patients were randomly assigned to the SN group (n = 30) or the DN group (n = 30). Both groups underwent EMS based on a presurgical plan. The primary outcomes were patient-reported QoL and analgesic use during the first week, while the secondary outcome was the duration of guided procedures, including osteotomy and root-end resection. QoL was assessed using a visual analog scale-based questionnaire. The questionnaire evaluated symptoms (pain, swelling, bleeding) and functional impact (mouth opening, chewing, talking, sleeping, daily routine), with average scores for each component calculated daily. The Mann-Whitney U test was used to compare QoL scores and surgery duration between groups, with statistical significance set at P < .05.

RESULTS

Postoperative adverse reactions within the first week after SN- and DN-aided EMS were short-lived, peaking early in the postoperative period and gradually subsiding. No significant differences were observed in QoL or analgesic use between the SN and DN groups. Participants in the SN group had significantly shorter surgery duration compared to DN group.

CONCLUSION

Both SN and DN enable minimally invasive EMS with equivalent patient-centered outcomes, though SN demonstrates a significant advantage in reducing the duration of guided osteotomy and root-end resection. These findings provide patient-centered reference metrics to guide the selection between the 2 guided approaches in clinical practice.

CBCT-Assessed Outcomes and Prognostic Factors of Primary Endodontic Treatment and Retreatment: A Systematic Review and Meta-Analysis

INTRODUCTION

Periapical radiographs have limitations in assessing endodontic treatment outcomes, which can be addressed by cone-beam computed tomography (CBCT). This systematic review evaluates primary root canal treatment and retreatment outcomes using CBCT, focusing on periapical healing, success, and prognostic factors.

METHODS

A literature search (in PubMed, Embase, and Web of Science) was performed up to March 8, 2024, in collaboration with a medical information specialist. Three reviewers (J.F.B.M., A.C.G, P.D.N.) independently performed article selection and data extraction. Risk of bias was assessed, and evidence quality using the Grading of Recommendations, Assessment, Development, and Evaluation approach. Meta-analysis and meta-regression established pooled periapical healing and outcome rates, 95% confidence intervals (CIs), and identify outcome predictors (P < .05).

RESULTS

Nineteen studies were included in the meta-analysis. The pooled periapical healing rate using "loose criteria" was 87% (95% CI: 81%-91%) for teeth and 84% (95% CI: 78%-88%) for roots; using "strict criteria" was 36% (95% CI: 22%-53%) for teeth, and 44% (95% CI: 16%-76%) for roots. The weighted pooled success rates for teeth were 85% (95% CI: 80%-89%) under "loose criteria" and 45% (95% CI: 31%-59%) under "strict" criteria. Meta-regression identified outcome predictors include number of visits, irrigant type, tooth type, operator experience, apical preparation size and taper, and obturation technique.

CONCLUSIONS

CBCT reveals lower success rates under strict criteria compared to loose criteria (36% vs 88%). While CBCT offers greater diagnostic accuracy, its routine use for outcome evaluation may not be necessary, as it yields results similar to periapical radiograph under loose criteria.

In vitro assessment of needle and irrigant penetration when using different irrigation needle tips

Objective

The aim of this study was to compare the needle and irrigant penetration depth of a newly developed multi-vented polymer needle (30G), with three established needle designs - an open-ended metal needle (30G), a side-vented polymer needle (30G), and a notched metal needle (27G) used as a reference control. The effect of manual dynamic activation (MDA) was also measured. The null hypotheses were that the irrigant penetration would be the same regardless of needle tip, and the addition of MDA would make no difference in terms of irrigant penetration.

Materials and methods

A total of 120 mesial roots from mandibular molars were instrumented to a size 25/07, with reciprocating files. The maximum needle penetration depth was measured for each needle tip, using a rubber stop. Syringe irrigation was performed using a sodium diatrizoate solution, first with needle placement halfway down the root canal (working length subtracted from the canal length), and then 1 mm from the working length. MDA was performed. A digital radiograph was taken before the initial irrigation, after the initial irrigation, after the final irrigation, and after MDA. Digital subtraction was performed, and irrigant penetration was measured by a blinded operator. Non-parametric statistical tests were conducted using Mann-Whitney U-test and Wilcoxon signed-rank test.

Results

The multi-vented polymer needle had a significantly deeper needle penetration (mean value: 99%), compared to other test needles. The deepest irrigant penetration was achieved using the multi-vented polymer needle (mean value: 98%) and the open-ended metal needle (mean value: 99%). A significantly deeper irrigant penetration, was achieved by adding MDA, regardless of needle tip.

Conclusions

The multi-vented polymer needle and the open-ended metal needle showed superior performance in terms of irrigant penetration. However, the irrigant penetration only managed to reach the working length when MDA was added.

Reporting quality of scoping reviews in endodontics: A meta-research study

OBJECTIVES

To evaluate the reporting quality of Scoping Reviews (ScRs) in endodontics according to the PRISMA Extension Checklist for Scoping Reviews (PRISMA-ScR) and to analyse their association with a range of publication and methodological/reporting characteristics.

METHODS

Pubmed, Scopus, and Web of Science databases were searched up to 31 January 2024 to identify scoping reviews in the field of endodontics. An additional search was performed in three leading endodontic journals. Study selection and appraising the quality of the studies was carried out independently by two reviewers. Each of the 20 PRISMA-ScR items were allocated a score of either 0, 0.5 or 1 to reflect the completeness of the reporting. An item-specific and overall percentage reporting quality score was calculated and reported through descriptive statistics across a range of publication, as well as methodological/reporting characteristics. A univariable and multivariable quantile regression was performed to identify the effect of publication and methodological/reporting characteristics (year of publication, journal, inclusion of an appropriate reporting guideline, and study registration) on the overall percentage reporting quality score. Association of reporting quality score with publication characteristics was then investigated.

RESULTS

A total of 40 ScRs were identified and included for appraisal. Most of the studies were published from 2021 onwards. The overall median reporting quality score was 86%. The most frequent items not included in the studies were: a priori protocol registration (22/40 compliant; 55%), and reporting of funding (16/40 compliant; 40%). Other key elements that were inadequately reported were the abstract (7/40 compliant; 18%), the rationale and justification of the ScR (21/40 compliant; 52%) and the objectives of the study (18/40 compliant; 45%). Studies that adhered to appropriate reporting guidelines were associated with greater reporting quality scores (β-coefficient: 10; 95%CI: 1.1, 18.9; p = .03). ScRs with protocols registered a priori had significantly greater reporting quality scores (β-coefficient: 12.5; 95%CI: 6.1, 18.9; p < .001), compared with non-registered reviews.

CONCLUSIONS

The reporting quality of the ScRs in endodontics varied and was greater when the ScR protocols were registered a priori and when the authors adhered to reporting guidelines.

Clinician/Patient-Reported Outcomes and Their Association After Root Canal Treatment

INTRODUCTION

The relationship between clinician-reported outcome measures (CROM) and patient-reported outcome measures (PROM) after root canal treatment is poorly understood. Oral health-related quality of life (OHRQOL) is a crucial PROM. Determination of the minimal important difference (MID) is critical for determining patients' perspective of treatment effectiveness, but the MID required to perceive any meaningful change in the OHRQOL after root canal treatment remains unclear. The aim of this prospective study was to investigate the relationship between the clinical outcome and OHRQOL after root canal treatment and to determine the corresponding MID values.

METHODS

Patients (N = 64) requiring primary nonsurgical root canal treatment were recruited. Clinical and radiographic (cone-beam computed tomography) assessment of treatment outcomes was performed at the 12-month follow-up. OHRQOL and pain were evaluated preoperatively and at the 12-month follow-up using the Oral Health Impact Profile-14 and visual analog scale, respectively. P < .05 was considered statistically significant. MID was assessed using distribution- and anchor-based approaches.

RESULTS

The final analysis included 47 patients. The clinical outcome was favorable for 92.6% of teeth. OHRQOL and pain showed significant improvement after treatment (P < .001). No significant association was found between clinical outcome and OHRQOL (P > .05). The mean Oral Health Impact Profile-14 score change (ie, 13.6) was greater than the range of MID values determined.

CONCLUSIONS

Root canal treatment significantly improves OHRQOL. Improvement in the OHRQOL score was greater than the MID values determined, implying a clinically significant change. However, PROM (OHRQOL) does not appear to be correlated with CROM.

Oral health-related quality of life and perceptions of patients following primary root canal treatment or non-surgical retreatment

This retrospective cohort study compared the effect of primary root canal treatment (RCT) with root canal retreatment (Re-RCT) on patient-reported outcomes in Kuala Lumpur, Malaysia. Forty randomly selected adults participated (RCT n = 20; Re-RCT n = 20). The impact their dentition had on the Oral Health Impact Profile-14 (OHIP-14) was assessed by calculating the prevalence of oral health impact, and the severity score. Focus group discussions using a semi-structured guide were arranged through an online meeting platform. Qualitative content analysis identified common themes, and relevant quotes gathered. The impact on OHIP-14 was limited for both RCT and Re-RCT groups with no significant differences in the prevalence of oral health impact. Significant differences were found for functional limitation (RCT higher) and psychological discomfort (Re-RCT higher). Common themes from the discussions include the importance of retaining teeth, the significance of effective communication between clinicians and patients and that the respondents were satisfied with the treatment.

Evaluating the Diagnostic Accuracy of an AI-Driven Platform for Assessing Endodontic Treatment Outcomes Using Panoramic Radiographs: A Preliminary Study

Background/Objectives: The purpose of this preliminary study was to evaluate the diagnostic performance of an AI-driven platform, Diagnocat (Diagnocat Ltd., San Francisco, CA, USA), for assessing endodontic treatment outcomes using panoramic radiographs (PANs). Materials and Methods: The study included 55 PAN images of 55 patients (15 males and 40 females, aged 12-70) who underwent imaging at a private dental center. All images were acquired using a Hyperion X9 PRO digital cephalometer and were evaluated using Diagnocat, a cloud-based AI platform. The AI system assessed the following endodontic treatment features: filling probability, obturation adequacy, density, overfilling, voids in filling, and short filling. Two human observers independently evaluated the images, and their consensus served as the reference standard. The diagnostic accuracy metrics were calculated. Results: The AI system demonstrated high accuracy (90.72%) and a strong F1 score (95.12%) in detecting the probability of endodontic filling. However, the system showed variable performance in other categories, with lower accuracy metrics and unacceptable F1 scores for short filling and voids in filling assessments (8.33% and 14.29%, respectively). The accuracy for detecting adequate obturation and density was 55.81% and 62.79%, respectively. Conclusions: The AI-based system showed very high accuracy in identifying endodontically treated teeth but exhibited variable diagnostic accuracy for other qualitative features of endodontic treatment.

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.

Effect of treatment variables on apical extrusion of debris during root canal retreatment: A systematic review and meta-analysis of laboratory studies

Background

This study aimed to systematically and comprehensively review the effect of various treatment variables on apically extruded debris (AED) during non-surgical root canal retreatment (NSRCRT).

Methods

The study protocol is shared in the Open Science Framework database (https://osf.io/kjtdg/?view_only=17060180705745ec9dae9a01614f3880). An electronic search was conducted up to July 2022 to reveal related studies. Two reviewers critically assessed the studies for eligibility against inclusion and exclusion criteria and data extraction. Quantitative data synthesis was performed, and the risk of bias in the studies was also evaluated.

Results

Forty-six studies were included in the systematic review and 14 in the meta-analysis. Conflicting or limited evidence was found for the effect of sealer type, obturation technique, and solvent use. The manual instrumentation increased the amount of AED compared to rotary instrumentation during the removal of filling materials (P<0.001). There was no significant difference in the amount of AED between the use of rotary and reciprocating files during the removal of filling materials (P=0.181).

Conclusion

Rotary instruments can be recommended instead of manual instruments during the removal of filling materials to control the amount of AED. Further studies with a low risk of bias are needed to clarify the effect of other treatment variables on AED during NSRCRT.

Effect of photodynamic therapy on the healing of periapical lesions after root canal retreatment: 1-year follow up randomized clinical trial

BACKGROUND

The aim of this randomized clinical trial was to evaluate the effects of photodynamic therapy (PDT) after traditional activated final irrigation protocol (ultrasonically activated irrigation, UAI) on periapical lesion healing after single-visit root canal retreatment.

METHODS

We included 36 patients with asymptomatic chronic apical periodontitis with periapical lesions larger than 5 mm and teeth sensitive to percussion and palpation, who had previous root canal treatment. All patients who signed informed consent underwent cone-beam computed tomography (CBCT) to determine and calculate the preoperative volume of the periapical lesion. Patients were randomly distributed into two groups according to the final disinfection protocol: Group 1; UAI (NaOCl, EDTA, and NaOCl), Group 2; UAI + PDT. All patients underwent single-visit root canal retreatment using rotary instrumentation and standardized irrigation (3 %NaOCl) by the same endodontist. The root canals were filled with epoxy resin-based sealer and single-cone gutta-percha, followed by control radiography. After one year, a new CBCT scan of the teeth was performed to calculate the reduction in the initial periapical lesion as a measure of periapical healing. For the statistical analysis, the chi-square test variants, Fisher's exact test and the Fisher-Freeman-Halton test were used at the level of significance set at 5 %.

RESULTS

There were no significant differences between the groups in terms of age, sex, preoperative and postoperative lesion volume (p > 0.05), and reduction of periapical lesion volume (median, 86.98 % for UAI and 79.72 % for UAI+PDT) (p = 0.970). Additional use of PDT after UAI did not contribute to the healing of periapical lesions.

CONCLUSION

The UAI and UAI+PDT protocols had equal effects on healing of periapical lesion.

Endodontic Orthograde Retreatments: Challenges and Solutions

Endodontic orthograde retreatments are considered one of the possible treatment options in case of post-treatment diseases considering the promising results present in the literature. Despite this, a plethora of articles have been published on this topic, and drawing conclusions could be challenging. For this reason, this review aims to summarize the crucial points on each aspect of non-surgical endodontic retreatments, discussing and comparing the current protocols, techniques, materials, and indications. Taking into consideration data from the literature, in terms of diagnosis, CBCT should be considered the first choice, since it can thoroughly affect the diagnosis and treatment plan. Regarding the procedural phases, some conclusions can be drawn: when present, coronal restoration materials such as crowns, partial prostheses, post, and core should be removed; the use of magnification devices, ultrasonic instruments, and an in-depth interpretation of radiographic images with both 2D and 3D images are strongly recommended during the orifice location; additional protocols such as irrigants activation, ultrasonic cleaning, and rotary or reciprocating instrumentation of treated canals are strongly recommended for filling materials removal and to achieve a high-quality chemo-mechanical disinfection; perforations should be treated as soon as possible, and the material of choice to treat them is the MTA or other calcium-silicate-based repair materials; the presence of ledges does not intrinsically reduce the success rate of RCRts if properly managed; in case of instrument fragments, their removal should be considered as the first treatment option, however many variables should be considered to select the proper technique or consider the option of bypassing.

Process-related Factors Are as Important as Outcomes for Patients Undergoing Nonsurgical Root Canal Treatment, Nonsurgical Root Canal Retreatment, and Endodontic Microsurgery

INTRODUCTION

There is considerable variation in the reporting of treatment outcomes in endodontics. Patient-centered outcomes are often inadequately reported in endodontic outcome studies. This paper explores patients' expectations and reported outcomes in nonsurgical root canal treatment (NS-RCT), nonsurgical root canal retreatment (NS-ReTx), and endodontic microsurgery (EMS).

METHODS

We used a qualitative description approach and conducted telephone and virtual semi-structured interviews with participants who had the following treatments within the preceding 3-12 months: NS-RCT (n = 10), NS-ReTx (n = 10), or EMS (n = 10). Half of these treatments were performed by senior endodontic residents in an academic setting and the other half by a community-based endodontist at a private practice.

RESULTS

Participants identified several outcomes that were important to them and integral to treatment success, such as tooth survival, resolution of symptoms, aesthetics, and radiographic healing. Process-related factors were as important as treatment outcomes for participants. Communicating with and educating patients during treatment increased participants' satisfaction and lowered their stress. Dissatisfaction was linked to the lack of a comprehensive treatment and follow-up plan. Thorough planning ensured that patients were fully informed and had a structured approach to achieving their desired outcomes.

CONCLUSIONS

This study provides a list of outcomes that are important for patients undergoing NS-RCT, NS-ReTx, and EMS. These outcomes should be considered when developing a core outcome set related to endodontic treatments. Additionally, this study reports patients' expectations regarding process-related factors that are essential for providing patient-centered care and improving patient experience.

Apexification Outcomes in the United States: A Retrospective Cohort Study

INTRODUCTION

This epidemiological analysis used procedure codes from dental insurance claims data to identify apexification cases and evaluate survival at the tooth-level.

METHODS

Dental insurance claims data from New York State (2006-2019) and Massachusetts (2013-2018) were used in an observational, retrospective cohort study to evaluate the provision and treatment outcomes of apexification. Statistical analyses included Kaplan-Meier survival estimates and Cox proportional hazards regression. Cox proportional hazard regression was used to evaluate the hazard of adverse event occurrence by age, gender, tooth type, placement of permanent restoration, and dental provider type. A sensitivity analysis evaluated potential bias in the survival estimates and adjusted hazard ratios (aHRs) due to differential loss to follow-up. Robust standard errors were used to account for potential dependence between teeth within an individual.

RESULTS

The analytic cohort of 575 individuals included 632 teeth, with an average follow-up time of 64 months. The survival rates of apexification procedures were 95% at 1 year; 93% at 2 years; 90% at 3 years; and 86% at 5 years. Tooth retention following apexification was 98% at 1 year; 96% at 2 years; 95% at 3 years; and 90% at 5 years. Tooth type and subsequent placement of a permanent restoration were significant predictors of survival after apexification.

CONCLUSIONS

The procedural and tooth survival outcomes of apexification were high and comparable to studies that analyzed clinical data on tooth survival following apexification.

Flare-ups After Nonsurgical Retreatments: Incidence, Associated Factors, and Prediction

INTRODUCTION

The aims of this study were to determine the incidence, associated factors, and predictability of flare-ups after nonsurgical retreatments (NSRetx).

METHODS

All patients (n = 3,666) who received NSRetx by 3 endodontists in 2 endodontic offices during a period of 6 years (2016-2022) were included. Demographic, diagnostic, and procedural data were collected. A flare-up was defined as moderate-severe pain with/without swelling that took place within 14 days of initiation of NSRetx and resulted in an unscheduled appointment. Bivariate analyses on the entire cohort and multivariable analyses on cases with complete dataset (n = 2,846) were performed to identify significant associations. A Random Forest algorithm was used to make a prediction model.

RESULTS

Incidence of flare-ups was 3.95% (n = 145). Increased risk of flare-ups was associated with diabetes (adjusted odds ratio [AOR] = 2.01; 95% confidence interval [CI], 1.01-3.97), mandibular teeth (AOR = 1.67; 95% CI, 1.11-2.52), moderate-severe preoperative pain on percussion (AOR = 2.13; 95% CI, 1.31-3.50), and pain on palpation (AOR = 1.63; 95% CI, 1.01-2.64). Lower risk of flare-up was associated with high blood pressure (AOR = 0.44; 95% CI, 0.21-0.82) (P < .05). The prediction model was not able to predict flare-ups with sufficient confidence (precision = 0.13).

CONCLUSIONS

Incidence of flare-ups following NSRetx was low (∼4%) and had a weak but significant association with the history of diabetes. Moderate-severe pain on percussion, pain on palpation (any intensity), and mandibular teeth had a significant association with flare-ups. The history of high blood pressure was associated with lower risk of flare-ups. Flare-ups were difficult to predict in this clinical setting.

The importance of establishing a core outcome set for endodontic clinical trials and outcomes studies

Endodontic therapy aims to preserve teeth by preventing and treating apical disease, therefore, evaluation of treatment outcome in clinical trials and outcomes studies should effectively assess if it achieves these aims. Traditionally, treatment outcomes have been reported by clinicians after history and clinical examination in what is known as clinician-reported outcomes (CROs). Much less commonly employed however, are patient-reported outcomes (PROs) in which patients directly report on their condition. Endodontic treatment outcome reporting is evolving from a focus on CROs to increasing consideration for patient and disease-focused outcomes, with different criteria being proposed for assessment of treatment outcomes. Unfortunately, this has led to considerable variability and a lack of consensus on the definition, appropriate measurement and reporting of these outcomes. Heterogeneity in outcome reporting in clinical research provides a significant major barrier to conduct meta-analysis, guidelines development, clinical decision making, and ultimately affecting patient care. These effects could, however, be reduced by the establishment of a core outcome set (COS) in endodontics, which is defined as an agreed, standardized set of outcomes that should be included, measured and reported as a minimum in all trials and outcome studies. COS development is a regulated and validated process requiring involvement of appropriate stakeholders as well as a rigorous methodology. To date, COS has been developed for the management of traumatic dental injuries, orthodontic and periodontal treatment and is currently being developed for endodontic treatment. The aim of this review is to discuss the importance of COS in endodontics with focus on the evidence for and impact of heterogeneity in reporting endodontic treatment outcomes. An overview of an ongoing process for development of COS for different endodontic treatment modalities will also be provided.

Patient-related outcomes and Oral Health-Related Quality of Life in endodontics

There is increased interest in outcome measures that complement the classic goal of endodontics, being the prevention and healing of apical periodontitis. Possible outcome measures can be subdivided into patient-centred outcomes (PCOs), encompassing data collected by nonpatients aiming to assess the effectiveness of an intervention and patient-reported outcomes (PROs), which are reported directly by the patient. PROs can be subsequently classed into PRO measures that ascertain patients' view of their symptoms, their functional status, and their health-related quality of life, and patient-reported experience measures that focus on aspects including the humanity of care, patient satisfaction, patient preference and adherence, personal costs, expectation fulfilment, and decision regrets. The present review aims to define various patient-related outcomes and discuss the literature available regarding PCOs and PROs in endodontics. This includes those proposed to assess the effectiveness of endodontic treatment for pulpitis and apical periodontitis for use in the development of European Society of Endodontology S3-level clinical practice guidelines that have been included by all working groups, except for the radiographic assessment of apical periodontitis. Based on limited evidence in the field, it can be summarized that after recall periods of various lengths, endodontic treatment is associated with a high likelihood of tooth survival and limited need for further intervention, including extraction and further restorative procedures. Oral Health-Related Quality of Life (OHRQoL) is likely to improve following the completion of treatment. Nonetheless, the literature assessing the association between OHRQoL and endodontics is hampered by the use of instruments that have not been previously validated. Amongst the remaining outcome measures discussed in the present review, it is worth highlighting that there is only one study assessing exacerbations in teeth with the presence of endodontic pathosis, which suggests a very low incidence of this adverse effect following endodontic treatment. Patients' expectation fulfilment, adherence, and satisfaction are closely inter-related and depend also on various nonclinical factors. Further studies assessing PCOs and PROs, in association with healing and prevention of apical periodontitis, are required to better understand endodontic treatment from the perspective of patients.

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.

Dental patient-reported outcomes following traumatic dental injuries and treatment: A narrative review

Dental patient-reported outcomes (dPROs) are self-reported descriptions of a patient's oral health status that are not modified or interpreted by a healthcare professional. Dental patient-reported outcome measures (dPROMs) are objective or subjective measurements used to assess dPROs. In oral healthcare settings, the emphasis on assessing treatment outcomes from the patient's perspective has increased and this is particularly important after traumatic dental injuries (TDIs), as this group of injuries represent the fifth most prevalent disease or condition worldwide. The purpose of this review is to summarize the current use of dPROs and dPROMs in the field of dental traumatology. Oral Health-Related Quality of Life, pain, swelling, aesthetics, function, adverse effects, patient satisfaction, number of clinical visits and trauma-related dental anxiety are the key dPROs following TDIs. Clinicians and researchers should consider the well-being of patients as their top priority and conduct routine evaluations of dPROs using measures that are appropriate, accurate and reflect what is important to the patient. After a TDI, dPROs can assist clinicians and patients to choose the best management option(s) for each individual patient and potentially improve the methodology, design and relevance of clinical studies.

Outcomes reporting in systematic reviews on non-surgical root canal treatment: A scoping review for the development of a core outcome set

BACKGROUND

Studies related to non-surgical root canal treatment are amongst the most frequently performed clinical studies in endodontics. However, heterogeneity in reporting outcomes and lack of standardization is a significant challenge to evidence synthesis and guideline development.

OBJECTIVES

The aims of the present scoping review were to (a) identify outcomes reported in systematic reviews evaluating non-surgical root canal treatment; (b) identify how and when the reported outcomes were measured; (c) assess possible selective reporting bias in the included studies. The information obtained in this study should inform the development of a core outcome set (COS) for non-surgical root canal treatment.

METHODOLOGY

Structured literature searches were performed to identify systematic reviews on non-surgical root canal treatments published in English between January 1990 and December 2020. Two reviewers undertook study selection and data extraction. Outcomes were categorized according to a healthcare taxonomy into five core areas (survival, clinical/physiological changes, life impact, resource use, and adverse events). The outcome measurement tools and length of follow-up were recorded.

RESULTS

Seventy-five systematic reviews were included, of which 40 included meta-analyses. Most reviews reported on physiological and clinical outcomes, primarily pain and/or radiographic assessment of periapical status, and a variety of measurement tools and scales were used. Few reviews focused on tooth survival, life impact, resources, and adverse events. The heterogeneity amongst the reviews was large on all parameters. Less than 40% of the reviews assessed the risk of selective reporting.

DISCUSSION

Overall aims of the included reviews were highly heterogenic; thus, outcomes and how they were measured also varied considerably. Patient-centred outcomes and the use of resources were rarely reported on.

CONCLUSIONS

Most studies reported on physiological and clinical outcomes, in particular pain and/or radiographic healing. Measurement tools, scales, thresholds, and follow-up periods varied greatly within each outcome, making comparison across studies complicated. Less than 40% of the reviews assessed risk of selective reporting; thus, selective bias could not be ruled out. The presented information on reported outcomes, measurement tools and scales, and length of follow-up may guide the planning of future research and inform the development of a COS for non-surgical root canal treatment.

Outcomes reporting in systematic reviews on vital pulp treatment: A scoping review for the development of a core outcome set

BACKGROUND

A large number of research reports on vital pulp treatment (VPT) has been published over the last two decades. However, heterogeneity in reporting outcomes of VPT is a significant challenge for evidence synthesis and clinical decision-making.

OBJECTIVES

To identify outcomes assessed in VPT studies and to evaluate how and when outcomes are measured. A subsidiary aim was to assess evidence for selective reporting bias in the included studies. The results of this review will be used to inform the development of a core outcome set (COS) for endodontic treatments.

METHODS

Multiple healthcare bibliographic databases, including PubMed/MEDLINE, Ovid EMBASE, Scopus, Cochrane Database of Systematic Reviews and Web of Science were searched for systematic reviews published between 1990 and 2020, reporting on VPT. Screening, data extraction and risk of bias assessment were completed independently by two reviewers. Outcomes' information was extracted and aligned with a healthcare taxonomy into five core areas: survival, clinical/physiological changes, life impact, resource use and adverse events.

RESULTS

Thirty-six systematic reviews were included, 10 reporting on indirect pulp capping or selective caries removal, nine on direct pulp capping, eight on pulpotomy and nine on combined VPTs. There was considerable variation in the outcomes reported in these reviews and their included studies. Clinician-reported outcomes were used considerably more often than patient-reported outcomes. A range of instruments and time points were used for measuring outcomes. Several of the reviews were assessed as having low risk of selective reporting bias, but many did not specifically report this domain, whilst others did not provide risk of bias assessment at all.

DISCUSSION

Considerable variation in selection of outcomes and how and when they are measured and reported was evident, and this heterogeneity has implications for evidence synthesis and clinical decision-making.

CONCLUSIONS

Whilst there is a lack of consistency, several potentially important outcomes for VPT, including pulp survival, incidence of post-operative pain and need for further intervention, have been identified which could inform the development of a COS for endodontic treatment.

REGISTRATION

Core Outcome Measures in Effectiveness Trials (COMET) (No. 1879).

Comparison Study of Diagnosis and Treatment Planning for Dental Infections between Dental Students and Practitioners

This study aimed to access the knowledge in diagnosing dental infections and the practice in treatment planning for the affected teeth among dental practitioners (DPs) and senior (final-year) students. A survey questionnaire containing two cases (Case A; periodontal abscess and Case B; periapical abscess) with four questions per case was delivered to potential participants. Fifty-nine DPs voluntarily participated in the survey. For senior students, the case study was a part of their course requirements; one of the two cases (either Case A or B) was randomly assigned to the 126 seniors. The distribution of responses was significantly different between the DP and senior groups except for the diagnosis of Case B (Fisher’s exact test; p = 0.05). Only 31% of the participants diagnosed Case A as periodontal abscess; most of them selected periodontal surgery as the first treatment option. Despite a high agreement in diagnosing Case B, the choice of treatment was significantly different; the most frequent treatment option was extraction (51%) from the DP group and root canal retreatment (57%) from the senior group. The study revealed that the diagnosis of periodontal abscess was more challenging than that of periapical abscess among dental professionals.

A critical analysis of research methods and experimental models to study irrigants and irrigation systems

Irrigation plays an essential role in root canal treatment. The purpose of this narrative review was to critically appraise the experimental methods and models used to study irrigants and irrigation systems and to provide directions for future research. Studies on the antimicrobial effect of irrigants should use mature multispecies biofilms grown on dentine or inside root canals and should combine at least two complementary evaluation methods. Dissolution of pulp tissue remnants should be examined in the presence of dentine and, preferably, inside human root canals. Micro-computed tomography is currently the method of choice for the assessment of accumulated dentine debris and their removal. A combination of experiments in transparent root canals and numerical modeling is needed to address irrigant penetration. Finally, models to evaluate irrigant extrusion through the apical foramen should simulate the periapical tissues and provide quantitative data on the amount of extruded irrigant. Mimicking the in vivo conditions as close as possible and standardization of the specimens and experimental protocols are universal requirements irrespective of the surrogate endpoint studied. Obsolete and unrealistic models must be abandoned in favour of more appropriate and valid ones that have more direct application and translation to clinical Endodontics.

Present status and future directions - irrigants and irrigation methods

Irrigation is considered the primary means of cleaning and disinfection of the root canal system. The purpose of this review was to set the framework for the obstacles that irrigation needs to overcome, to critically appraise currently used irrigants and irrigation methods, to highlight knowledge gaps and methodological limitations in the available studies and to provide directions for future developments. Organization of bacteria in biofilms located in anatomic intricacies of the root canal system and the difficulty to eliminate them is the main challenge for irrigants. Sodium hypochlorite remains the primary irrigant of choice, but it needs to be supplemented by a chelator. Delivery of the irrigants using a syringe and needle and activation by an ultrasonic file are the most popular irrigation methods. There is no evidence that any adjunct irrigation method, including ultrasonic activation, can improve the long‐term outcome of root canal treatment beyond what can be achieved by instrumentation and syringe irrigation. It is necessary to redefine the research priorities in this field and investigate in greater depth the penetration of the irrigants, their effect on the biofilm and the long‐term treatment outcome. New studies must also focus on clinically relevant comparisons, avoid methodological flaws and have sufficiently large sample sizes to reach reliable conclusions. Future multidisciplinary efforts combining the knowledge from basic sciences such as Chemistry, Microbiology and Fluid Dynamics may lead to more effective antimicrobials and improved activation methods to bring them closer to the residual biofilm in the root canal system.