Diagnostic accuracy of cone beam computed tomography used for assessment of apical periodontitis: an ex vivo histopathological study on human cadavers

A 22-year follow-up cross-sectional study on periapical health in relation to the quality of root canal treatment in a Belgian population

AIM

To investigate the prevalence of apical periodontitis (AP) and the technical standard of root canal treatment in a Belgian population, assess the association of different variables with periapical status, and compare the results to a similar study conducted 22 years previously.

METHODOLOGY

In this cross-sectional study, 614 panoramic radiographs of first-time adult attendees at the Dental School of the University Hospital of Ghent were examined. Recorded patient-level parameters included gender, age, number of teeth, number of root filled teeth, presence of any AP lesion, and number of implants. The following tooth-level data were collected: tooth presence, coronal status, quality of coronal restoration, post presence, type of root-filling material, length and density of root filling, root-end filling material, presence of AP, and adjacent implant. Multivariable multilevel binary logistic regression was used to explore the association between patient and tooth characteristics and AP prevalence. Risk differences and confidence intervals were calculated to compare the present with the previous study.

RESULTS

The prevalence of AP at patient and tooth level was 46.9% and 5.6%, respectively. Fifty-one per cent of the 614 patients had at least one root filled tooth, and 5.9% of the 14 655 teeth studied were root filled. AP was found in 45% of root filled teeth. Fifty-four per cent of the root-filled teeth were rated as inadequate. Multivariable multilevel logistic regression revealed that more teeth, more implants, fewer root-filled teeth, adequate density, adequate coronal restoration, and no caries reduced the likelihood of AP. There were no statistically significant differences between the two studies regarding the prevalence of root-filled teeth or AP and the technical quality of root canal treatment.

CONCLUSIONS

The prevalence of AP and the technical quality of root canal treatment in Belgium have not substantially changed over the last 22 years, despite the technological advancements and continuing education in the field.

Endodontic Microsurgery Outcomes over 10 Years and Associated Prognostic Factors: A Retrospective Cohort Study

INTRODUCTION

This retrospective cohort study aimed to evaluate long-term healing outcomes (10-17.5 years) after contemporary endodontic microsurgery (EMS) and identify the associated prognostic factors.

METHODS

Clinical and radiographic data of an EMS cohort (2006-2013) from the electronic database of the dental hospital were reviewed retrospectively by 2 independent examiners to determine their survival and healing outcomes, and potential prognostic factors were analyzed by Cox proportional hazards regression and logistic regression (α = 0.05).

RESULTS

Through strict inclusion and exclusion criteria and 721 EMS-treated teeth in the cohort, 309 (42.9%) were included (male = 35.0%; female = 65.0%; age = 45.83 ± 15.53 years) with a mean final follow-up of 152.26 ± 26.37 months (range, 120-211 months; median = 148 months). Clinical and radiographic assessments found an 80.5% 10-year survival rate with 63.4% of success. Collectively, tooth type, tooth mobility, preoperative lesion size, clinical crown-to-root ratio, and crown restorations at follow-up were significantly associated with long-term success and survival over 10 years.

CONCLUSIONS

The preoperative status and condition of the tooth including its alveolar bone support and adequate full-crown restorations may be relevant prognostic determinants of success and survival after EMS over time.

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.

Jawbone measurements of edentulous sites related to implant planning using magnetic resonance imaging compared to cone beam computed tomography: An ex vivo study

AIM

To compare measurements on images obtained by magnetic resonance imaging (MRI) and cone beam CT (CBCT) for height, width, and area in alveolar bone sites in human jaw specimens.

MATERIAL AND METHODS

Forty edentulous alveolar posterior sites in human cadaver specimens were imaged using CBCT scanners, and with zero-echo-time MRI (ZTE-MRI). Semi-automatic volume registration was performed to generate representative coronal sections of the sites related to implant planning. ZTE-MRI sections were also presented after grayscale inversion (INV MRI). Three observers measured bone height, bone width 5 mm from the alveolar crest, and bone area stretching from the width measurement to the top of the alveolar crest in the images. Interobserver agreement was assessed by intra-class correlation coefficients (ICC). The measurements were analyzed using two-way repeated measures ANOVA factoring observer and image type.

RESULTS

ICC was >0.95 for bone height, width, and bone area. No significant differences among observers (p = 0.14) or image type (p = 0.60) were found for bone height. For bone width, observer (p = 0.14) was not a significant factor, while ZTE-MRI produced width estimates that were significantly different and systematically smaller than CBCT-based estimates (p ≤ 0.001). Observer (p = 0.06) was not a significant factor regarding the bone area measurements, contrary to the imaging type where ZTE-MRI led to significantly smaller area estimates than CBCT (p ≤ 0.001).

CONCLUSION

Bone height measurements were essentially equivalent using CBCT and MRI. This was found regardless of grayscale choice for the MRI. However, ZTE-MRI resulted in smaller estimates of bone width and area.

Global cone-beam computed tomography adoption, usage and scan interpretation preferences of dentists and endodontists

AIM

This study investigated the adoption of cone-beam computed tomography (CBCT) by dentists and endodontists around the world, including their preferences in endodontic CBCT usage.

METHODOLOGY

An online questionnaire surveyed dental association members in Australia and New Zealand, and endodontic association members in Australia, Britain, Canada, Italy, New Zealand and the USA, about their CBCT training history, considerations in acquisition/interpretation, access to and usage of CBCT, preferred scan interpreter, and preferred endodontic scan settings. Data were analysed with Chi-squared, independent sample t-tests, Cochran's Q and McNemar's tests.

RESULTS

Responses from 578 endodontic specialists or postgraduates (Group E) and 185 non-endodontic dentists (Group NE) were included. Continuing professional education (CPE) was the most common source of CBCT training (69.2%). Factors considered in CBCT acquisition/interpretation included beam hardening (75.4%), radiation exposure (61.1%) and patient movement (58.3%). Group E reported higher CBCT usage (90.8%) than Group NE (45.4%, p < .001) and greater workplace access to CBCT (81.1% vs. 25.9%, p < .001). Scans were interpreted by the respondent in most workplace scans (83.3%) and externally taken scans (60.5%); Group E were significantly more likely to interpret themselves than Group NE. Small field of view (83.6%) and high resolution (86.6%) were most preferred as settings for endodontic CBCTs; Group NE were less likely to choose these settings. There were some geographic variations within Group E.

CONCLUSIONS

CBCT training was most commonly acquired via CPE. Endodontic respondents reported very high CBCT usage and access in the workplace. There are educational implications regarding CBCT limitations, appropriate applications and interpretation.

Alveolar bone morphology in patients with palatally-displaced maxillary lateral incisors before and after orthodontic treatment: A cone-beam computed tomography study

INTRODUCTION

Palatal displacement of maxillary anterior teeth is common in clinical practice. Previous studies have reported that the labial bone around palatally-displaced incisors is thinner than that around normally-placed teeth. Therefore, it is necessary to elucidate alveolar bone changes after alignment to guide orthodontic treatment. In this study, we investigated the alveolar bone changes around palatally-displaced maxillary lateral incisors before and after treatment, and the effects of extraction and age using cone-beam computed tomography.

METHODS

In this retrospective study, 55 patients with unilateral palatally-displaced maxillary lateral incisors were included. Three-dimensional alveolar bone changes were measured at three levels (25%, 50% and 75% of the root length) using cone-beam computed tomography. Group comparisons were made between displaced and control teeth, extraction and non-extraction groups, and adult and minor groups.

RESULTS

After orthodontic treatment, labiopalatal and palatal alveolar bone widths decreased at all measured levels. Labial alveolar bone width increased significantly at P25, but decreased at P75. Concavity decreased, while tooth-axis angle, tooth length, B-CEJ and P-CEJ increased. Changes in LB and LP at P75, B-CEJ and P-CEJ were statistically significant. After treatment, the tooth-axis angle on the PD side increased by 9.46°. The change in tooth-axis angle on the PD side was significantly smaller, and LB and LP decreased more at P75, in the extraction group.

CONCLUSIONS

Compared to the control teeth, alveolar bone thickness and height for the displaced teeth decreased more significantly after treatment. Tooth extraction and age also influenced alveolar bone changes.

Primary apical periodontitis correlates to elevated levels of interleukin-8 in a Swedish population: A report from the PAROKRANK study

AIM

To explore associations between root filled teeth, primary and secondary apical periodontitis, and levels of inflammatory markers in blood from patients with a first myocardial infarction and matched controls.

METHODOLOGY

Between May 2010 and February 2014, 805 patients with a first myocardial infarction and 805 controls, matched for sex, age, and postal code area, were recruited to the multicentre case-control study PAROKRANK (periodontitis and its relation to coronary artery disease). All participants underwent a physical and oral examination, as well as blood sampling. Using panoramic radiography, root filled teeth, primary apical periodontitis, and secondary apical periodontitis were assessed by three independent observers. Blood samples were analysed with enzyme-linked immunosorbent assay method for the following inflammatory markers: interleukin-1β (IL-1β), IL-2, IL-6, IL-8, IL-12p70, tumour necrosis factor-α, and high-sensitivity C-reactive protein (hsCRP). Additionally, white blood cell count and plasma-fibrinogen were analysed. Associations between endodontic variables and the levels of inflammatory markers were statistically analysed with Mann-Whitney U-test and Spearman correlation, adjusted for confounding effects of baseline factors (sex, age, myocardial infarction, current smoking, diabetes, family history of cardiovascular disease, education, marital status, and periodontal disease).

RESULTS

Mean age of the cohort was 62 years, and 81% were males. Root fillings were present in 8.4% of the 39 978 examined teeth and were associated with higher levels of hsCRP, fibrinogen, and leukocyte count, but lower levels of IL-2 and IL-12p70. After adjusting for confounders, root filled teeth remained associated with higher levels of fibrinogen, but lower levels of IL-1β, IL-2, IL-6, and IL-12p70. Primary apical periodontitis was found in 1.2% of non-root filled teeth and associated with higher levels of IL-8 (correlation 0.06, p = .025). Secondary apical periodontitis was found in 29.6% of root filled teeth but did not relate to the levels of any of the inflammatory markers.

CONCLUSIONS

This study supports the notion that inflammation at the periapex is more than a local process and that systemic influences cannot be disregarded. Whether the observed alterations in plasma levels of inflammatory markers have any dismal effects on systemic health is presently unknown but, considering the present results, in demand of further investigation.

Clinically Oriented CBCT Periapical Lesion Evaluation via 3D CNN Algorithm

Apical periodontitis (AP) is one of the most prevalent disorders in dentistry. However, it can be underdiagnosed in asymptomatic patients. In addition, the perioperative evaluation of 3-dimensional (3D) lesion volume is of great clinical relevance, but the required slice-by-slice manual delineation method is time- and labor-intensive. Here, for quickly and accurately detecting and segmenting periapical lesions (PALs) associated with AP on cone beam computed tomography (CBCT) images, we proposed and geographically validated a novel 3D deep convolutional neural network algorithm, named PAL-Net. On the internal 5-fold cross-validation set, our PAL-Net achieved an area under the receiver operating characteristic curve (AUC) of 0.98. The algorithm also improved the diagnostic performance of dentists with varying levels of experience, as evidenced by their enhanced average AUC values (junior dentists: 0.89-0.94; senior dentists: 0.91-0.93), and significantly reduced the diagnostic time (junior dentists: 69.3 min faster; senior dentists: 32.4 min faster). Moreover, our PAL-Net achieved an average Dice similarity coefficient over 0.87 (0.85-0.88), which is superior or comparable to that of other existing state-of-the-art PAL segmentation algorithms. Furthermore, we validated the generalizability of the PAL-Net system using multiple external data sets from Central, East, and North China, showing that our PAL-Net has strong robustness. Our PAL-Net can help improve the diagnostic performance and speed of dentists working from CBCT images, provide clinically relevant volume information to dentists, and can potentially be applied in dental clinics, especially without expert-level dentists or radiologists.

Applying artificial intelligence to detect and analyse oral and maxillofacial bone loss-A scoping review

Radiographic evaluation of bone changes is one of the main tools in the diagnosis of many oral and maxillofacial diseases. However, this approach to assessment has limitations in accuracy, inconsistency and comparatively low diagnostic efficiency. Recently, artificial intelligence (AI)-based algorithms like deep learning networks have been introduced as a solution to overcome these challenges. Based on recent studies, AI can improve the detection accuracy of an expert clinician for periapical pathology, periodontal diseases and their prognostication, as well as peri-implant bone loss. Also, AI has been successfully used to detect and diagnose oral and maxillofacial lesions with a high predictive value. This study aims to review the current evidence on artificial intelligence applications in the detection and analysis of bone loss in the oral and maxillofacial regions.

Treatment of pulpal and apical disease: The European Society of Endodontology (ESE) S3-level clinical practice guideline

BACKGROUND

The ESE previously published quality guidelines for endodontic treatment in 2006; however, there have been significant changes since not only in clinical endodontics but also in consensus and guideline development processes. In the development of the inaugural S3-level clinical practice guidelines (CPG), a comprehensive systematic and methodologically robust guideline consultation process was followed in order to produce evidence-based recommendations for the management of patients presenting with pulpal and apical disease.

AIM

To develop an S3-level CPG for the treatment of pulpal and apical disease, focusing on diagnosis and the implementation of the treatment approaches required to manage patients presenting with pulpitis and apical periodontitis (AP) with the ultimate goal of preventing tooth loss.

METHODS

This S3-level CPG was developed by the ESE, with the assistance of independent methodological guidance provided by the Association of Scientific Medical Societies in Germany and utilizing the GRADE process. A robust, rigorous and transparent process included the analysis of relevant comparative research in 14 specifically commissioned systematic reviews, prior to evaluation of the quality and strength of evidence, the formulation of specific evidence and expert-based recommendations in a structured consensus process with leading endodontic experts and a broad base of external stakeholders.

RESULTS

The S3-level CPG for the treatment of pulpal and apical disease describes in a series of clinical recommendations the effectiveness of diagnosing pulpitis and AP, prior to investigating the effectiveness of endodontic treatments in managing those diseases. Therapeutic strategies include the effectiveness of deep caries management in cases with, and without, spontaneous pain and pulp exposure, vital versus nonvital teeth, the effectiveness of root canal instrumentation, irrigation, dressing, root canal filling materials and adjunct intracanal procedures in the management of AP. Prior to treatment planning, the critical importance of history and case evaluation, aseptic techniques, appropriate training and re-evaluations during and after treatment is stressed.

CONCLUSION

The first S3-level CPG in endodontics informs clinical practice, health systems, policymakers, other stakeholders and patients on the available and most effective treatments to manage patients with pulpitis and AP in order to preserve teeth over a patient's lifetime, according to the best comparative evidence currently available.

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).

CBCT in contemporary endodontics

Cone-beam computed tomography (CBCT) is a three-dimensional imaging modality which can aid endodontic diagnosis and treatment planning. While there are guidelines available describing the indications, there are divergent philosophies on when this technology should be applied in clinical practice. This paper reviews the applications of CBCT including the clinical relevance of parameters which can be assessed, highlights the limitations of this technology, and provides guidance on how to maximise its clinical utility.

Alveolar bone measurements in magnetic resonance imaging compared with cone beam computed tomography: a pilot, ex-vivo study

OBJECTIVES

To compare alveolar bone height and width measurements from zero-echo-time MRI (ZTE-MRI) and cone beam CT (CBCT), in human specimens.

MATERIAL AND METHODS

Twenty posterior edentulous sites in human cadaver specimens were imaged with CBCT and ZTE-MRI. Bone height and width at 1, 3, 5, 7 and 9 mm from the top of the alveolar ridge was measured by two trained observers in cross-sections of a site where an implant was to be planned. Twenty percent of the sample was measured in duplicate to assess method error and intra-observer reproducibility (ICC). The differences between CBCT and ZTE-MRI measurements were compared (t-test).

RESULTS

Inter- and intra-observer reproducibility was >0.90. The method error (average between observers) for bone height was 0.45 mm and 0.39 mm, and for bone width (average) was 0.52 mm and 0.80 mm (CBCT and ZTE-MRI, respectively). The majority of the bone measurement differences were statistically insignificant, except bone width measurements at 5 mm (p ≤ .05 for both observers). Mean measurement differences were not larger than the method error.

CONCLUSION

ZTE-MRI is not significantly different from CBCT when comparing measurements of alveolar bone height and width.

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.

Factors that influence the outcomes of surgical endodontic treatment

Surgical endodontic treatment encompasses a broad spectrum of procedures, amongst which root-end cavity preparation and filling, retrograde root canal treatment and through-and-through endodontic surgery, may be classified under the umbrella term 'Root-end surgery'. This narrative review considers the available data on periapical healing, soft tissue healing, tooth survival and oral health-related quality of life (OHRQoL), following root-end surgery and the factors that affect its outcomes. The pooled periapical healed rate for the studies published up to 2021 was 69% (95% CI: 65%, 73%) but increased to 76% (95% CI: 66%, 86%) when only data from the 2020's studies were analysed. The prognostic factors consistently reported for periapical healing have included: pre-operative periapical lesion with complete loss of buccal plate, quality of root-end preparation, remaining thickness of apical root dentine and restorative status. Soft tissue healing of the reflected flap was found to have a positive association with periapical healing. The survival rates following root-end surgery range from 48% to 93%, with failure of periapical healing associated with root and crown fracture, being the predominant reasons for tooth extraction. The factors influencing impact of root-end surgery on patients' quality of life could not be adequately evaluated due to design flaws in the available studies. In conclusion, if root canal treatment failure due to leakage through cracks, fractures or restoration margin are excluded, the remaining cases may represent localized residual infection and inflammation at the periapex that should be amenable to predictable management with the aid of modern root-end surgery.

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).

Clinical decision making of post-treatment disease

Root-filled teeth presenting with signs of post-treatment disease is a common finding in virtually every dental practice. There is both empirical and experimental evidence that, as long as the condition is asymptomatic, it is often left untreated. Professional judgements and decision making in endodontics as in any medical discipline are based on qualified estimations of the probability and the value of relevant outcomes. In this paper we describe various aspects of clinical decision making in general, from a descriptive as well as a normative point of view, but with a particular focus on the condition of the root-filled tooth with post-treatment disease. We review how attention to various types of uncertainties are relevant for the decision-making process. Additionally, we discuss the nature of value judgements and different concepts of health and disease which are important for understanding the complexity of the clinical decision-making process. We also refer to a set of principal rules that can guide the clinician's decision making in every-day practice in front of a case with endodontic post-treatment disease. Finally, we provide some aspects on the sometime cumbersome decision whether to go for a non-surgical or surgical method, whenever a decision on retreatment has been made.

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.

Periapical Radiography versus Cone Beam Computed Tomography in Endodontic Disease Detection: A Free-response, Factorial Study

AIM

To assess and compare reader performance in interpreting digital periapical (PA) radiography and cone beam computed tomography (CBCT) in endodontic disease detection, using a free-response, factorial model.

MATERIALS AND METHODS

A reader performance study of 2 image test sets was undertaken using a factorial, free-response design, accounting for the independent variables: case type, case severity, reader type, and imaging modality. Twenty-two readers interpreted 60 PA and 60 CBCT images divided into 5 categories: diseased-subtle, diseased-moderate, diseased-obvious, nondiseased-subtle, and nondiseased-obvious. Lesion localization fraction, specificity, false positive (FP) marks, and the weighted alternative free-response receiver operating characteristic figure of merit were calculated.

RESULTS

CBCT had greater specificity than PA in the obvious nondiseased cases (P = .01) and no significant difference in the subtle nondiseased category. Weighted alternative free-response receiver operating characteristic values were higher for PA than CBCT in the subtle diseased (P = .02) and moderate diseased (P = .01) groups with no significant difference between in the obvious diseased groups. CBCT had higher mean FPs than PA (P < .05) in subtle diseased cases. Mean lesion localization fraction in the moderate diseased group was higher in PA than CBCT (P = .003). No relationships were found between clinical experience and all diagnostic performance measures, except for in the obvious diseased CBCT group, where increasing experience was associated mean FP marks (P = .04).

CONCLUSIONS

Reader performance in the detection of endodontic disease is better with PA radiography than CBCT. Clinical experience does not impact upon the accuracy of interpretation of both PA radiography and CBCT.

Apical periodontitis and associated factors in a rural population of southern Brazil: a multilevel analysis

OBJECTIVES

This study aims to evaluate the association between apical periodontitis (AP) and sociodemographic/clinical factors in a probability sample of individuals living in a rural area of southern Brazilian.

MATERIALS AND METHODS

A cross-sectional study was conducted involving 584 non-edentulous adult individuals who had undergone a full-mouth radiographic survey. Periapical status was analysed using the periapical index (PAI). Endodontic status was evaluated considering the occurrence of voids in the filling material and the root filling length. Crown status was classified based on the presence of caries, restorations, and prosthetic crowns. Sociodemographic variables, frequency of dental care, and periodontal disease were also registered. The data were analysed using hierarchical multilevel Poisson regression analysis. The multilevel structure was composed of three models: sociodemographic variables, clinical variables, and clinical variables adjusted by sociodemographic variables (α = 5%).

RESULTS

The prevalence of AP in the sample was 60.45%. AP was significantly associated with age, skin colour, schooling, periodontal disease, and frequency of dental care (P < 0.005). Among the 10,396 teeth evaluated, 868 (8.35%) had AP, which was significantly associated with tooth group, dental arch, crown status, and endodontic treatment (P < 0.005).

CONCLUSIONS

The prevalence of AP was high in the population studied. An older age, black/brown skin colour, low level of schooling, infrequent dental care, severe periodontal disease, mandibular teeth, posterior teeth, inadequate crown status, and having undergone endodontic treatment were significantly associated with the outcome. Clinical relevance This study about a rural probability sample reinforces that AP is still a recurrent oral health problem.

The Changes in Size of Periapical Lesions after Root Canal Treatments Assessed by Digital Periapical Radiography and Cone-Beam Computed Tomography: A 2-Years Prospective Clinical Study

Background and Objectives: There is limited information regarding comparison of long-term dynamics of periapical bone destruction estimated by digital periapical radiography (DPR) and by cone-beam computed tomography (CBCT). This study aimed to compare the radiographically assessed periapical changes of endodontically treated teeth over 2 years of follow-up and to analyse disagreements in periapical lesion size estimates around the same roots using DPR and CBCT. Materials and Methods: A total of 176 endodontically treated teeth, of 128 patients with apical periodontitis, were assessed by DPR and CBCT, at baseline and after 2 years. All periapical radiolucencies were categorised by severity (S0, S1, S2, S3) concerning their size. Descriptive statistics were used to report distribution of the radiolucencies at baseline and at follow-up, and their size transitions over 2 years. Site-specific comparison of the radiolucencies identified by two methods was performed using Z test and Pearson’s chi-square test. Results: majority of the detected radiolucencies were scored as S0: 65% and 68% at baseline; 89% and 83% at follow-up, by DPR and CBCT, respectively. Site-specific score comparison showed that disagreements comprised 18% and 20% of the total number of radiolucencies detected by DPR and CBCT, respectively. There were more disagreements between DPR and CBCT within categories S1 and S2 + S3 compared to S0: at baseline, they comprised 17–33% and after two years 62–95% of all detected radiolucencies within the category. 65% of non-matching score transitions over two years occurred between S0 and S1. The CBCT-based evaluation resulted in negative treatment outcomes for 10 more root canals than the DPR-based result. Conclusions: Most remarkable disagreement between DPR and CBCT recordings was observed within the radiolucency categories S2 and S3. However, the diagnostic accuracy of both radiographic methods was questionable as it resulted in a high proportion of non-matching S0-S1 lesion transitions over 2 years.

Factors related to apical periodontitis in a southern Brazilian population: a multilevel analysis

The aim of this cross-sectional study was to evaluate the effects of individual-level and tooth-level factors on apical periodontitis (AP) in an urban population in southern Brazil. A random sample of digital panoramic radiographs (n = 545) from a dental school database was evaluated. The diagnosis of AP was determined by using a dichotomous scale (yes/no). AP was assessed according to gender, age, presence and quality of endodontic treatment (ET), presence of an intracanal post, coronal condition, and dental group. Data were analyzed descriptively and through multilevel Poisson regression analysis, considering teeth characteristics (level 1) nested in individuals (level 2). In this sample of 545 participants, the prevalence of AP was 49.5% (n =2 70) and ET was 43.5% (n = 237). Considering 13,595 teeth, AP was identified in 596 (4.4%) and ET in 617 (4.5%). Of the teeth with ET, 153 (24.8%) presented AP. Among individual-level factors, the disease was not significantly associated with gender or age. For tooth-level factors, AP was significantly associated with ET quality: teeth with short fillings (< 3 mm) and teeth with over-fillings had 2.77 (CI: 1.95-3.94, p < 0.001) and 1.08 (CI: 0.39-2.98, p < 0.001) higher prevalence of AP, respectively. There was no association between AP and age, gender, dental group, coronal condition, or the presence of an intracanal post. AP was highly prevalent in this population, and multilevel analysis indicated a significant association with ET quality.

Retrograde peri-implantitis: incidence and possible co-existing factors. A retrospective analysis

OBJECTIVES

To evaluate the incidence of Retrograde peri-implantitis (RPI) generally and the incidence of RPI with an endodontic-treated adjacent tooth and/or a periapical radiolucency.

METHODS

The retrospective case-control study included the follow-up periapical images of single dental implants. Two calibrated graduate endodontic residents evaluated simultaneously the presence of RPI and the adjacent teeth status (a previous root canal treatment (RCT) and the periapical status).

RESULTS

Six hundred eleven dental implants were included in this study. Twenty-three implants with RPI were detected (the incidence of RPI was 3.7%). Thirty-one adjacent teeth to the implants with RPI were recognized. Out of them, seven teeth had a previous RCT and periapical radiolucency or no RCT and periapical radiolucency. The odds ratios for RPI in an implant with periapical radiolucency or with RCT at the adjacent tooth are 6.67 (95% CI 2.7-16.5), p<0.05; and 0.11 (95% CI 0.007 - 1.9), p>0.05 respectively.

CONCLUSIONS

Based on periapical radiographs, the RPI incidence was 3.7% in the present study. The incidence of RPI increased in cases with adjacent teeth that had periapical radiolucency. Previous RCT in teeth adjacent to implants without apical radiolucency is not correlated with RPI. © 2022 Australian Dental Association.

The outcome of endodontic treatment using an enhanced infection protocol in specialist practice

Objectives This study aims to determine the outcome of primary root canal treatment with specific enhanced infection control protocol. The secondary aim was to compare percentages of successful outcomes in this study with a previous study undertaken by the same operator using both periapical radiograph (PR) and cone beam computed tomography (CBCT).Materials and methods Root canal treatment of 110 teeth in 95 patients carried out by a single operator using an enhanced infection control procedure (disinfection of gutta percha before obturation, changing of gloves after each intraoperative radiograph and also before the start of the root canal obturation). PR and CBCT scans of 94 teeth in 87 patients were assessed 12 months after completion of primary root canal treatment and compared with their respective pre-treatment (diagnostic) PR and CBCT scans. Healing was assessed by a consensus panel consisting of two calibrated examiners. Comparison of the PR and CBCT images for 'healed' and/or 'healing' outcomes was performed using McNemar's test.Results The 'healed' rate (absence of periapical radiolucency) was 89.4% using PR and 78.7% for CBCT (p <0.046). This rate increased to 95.7% for PR and 92.6% for CBCT when the 'healing' group (reduced size of periapical radiolucency) was included (p <0.046).Conclusion The frequent changing of gloves during the course of endodontic treatment and disinfection of gutta percha points before obturation, together with the use of contemporary rotary files, resulted in a high success rate of primary root canal treatment compared to similar clinical studies conducted previously.

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).

Analysis of advances in research trends in robotic and digital dentistry: An original research

Introduction:

The world has been transformed after invention of robotics, digitalization, and artificial intelligence. Their application in the medical field is well recorded; however, their application in dentistry is still being recognized. Hence, in our study, we aimed to analyze the advances in research trends in the digital and the robotics specifically to the dental fields.

Material and Methods:

We conducted a search for articles that recorded the use of robots, digitalization, and artificial intelligence in dentistry, specifically in endodontics. We piloted a questionnaire study to evaluate the awareness and application of these technologies by the clinicians. The results are presented as various applications of these technologies and the number of the articles for various terminologies. The application of these technologies was compared between the clinicians using ANOVA, with P < 0.05 being significant.

Results:

We observed a significant difference between the clinicians regarding the application of these technologies and lower awareness was noted. None of the participants used these technologies in practice. Of the total 20 articles that we had finalized, we observed that these technologies helped in studying the various pathologies and structures that were unviewed previously, as well as treatments, prognosis, and outcomes.

Conclusions:

There is a low awareness of these advanced technologies and application in routine practice. These technologies show greater precision and accuracy. However, the application of these in daily clinical practice and the economy are to be evaluated.

How do we and how should we deal with uncertainty in Endodontics?

In many clinical cases a dentist may feel certain when for example diagnosing, deciding on treatment, or assessing the prognosis—in other cases many dentists may feel a degree of doubt or uncertainty. This paper aims to explore the philosophical concept of uncertainty and its different dimensions, using the condition “persistent apical periodontitis associated with a previously root filled tooth” as an example. Acknowledging that uncertainty exists in any clinical situation can be perceived as uncomfortable, as some might regard it as a weakness. Whilst some types of uncertainty met in dental practice can be addressed and reduced, there are other types which are inevitable and must be accepted. To make sound decisions, it is pertinent that the dentist reflects on and values the consequences of uncertainty. In this paper, a conceptual model is presented by which the dentist can identify the type of uncertainty in a clinical case, making it possible to decide on a strategy on how to manage the uncertainty and its possible consequences, with the aim to support the dentist's care for their patients. The understanding that uncertainty exists and the ability to acknowledge and be comfortable with it when making decisions should be addressed throughout our professional career, and thus ought to be developed during undergraduate education. Some suggestions on how teachers could target this are given in the paper.

Is Coronal Restoration a Predictor of Posttreatment Apical Periodontitis?

Objectives  To investigate the posttreatment apical periodontitis (AP) in endodontically treated teeth through a multivariate approach and to analyze the relative importance of quality and type of coronal restoration as predictors of periapical disease.

Materials and Methods  The present study sample was drawn within 2-year period from the 1,072 consecutive patients older than 18 years, first time attending the Dental Clinic of the Clinical Hospital Center Rijeka, Croatia. A total of 1,350 endodontically treated teeth were included in the study. For each tooth, the periapical status, root filling quality, intracanal post, separated file presence, marginal bone loss, and quality and type of coronal restoration were recorded.

Statistical Analysis  Chi-square tests were used to analyze the variations in the periapical status, quality of root canal filling, and quality of coronal restoration in different tooth types. The effect of explanatory variables on periapical status was explored using univariate and multivariate logistic regression models. The outcome variable was set as the presence versus absence of AP in the tooth.

Results  Multivariate logistic regression analysis revealed statistically significant associations and increased risk for AP presence in molars (odds ratio [OR] = 2.15; p  < 0.001), teeth positioned in mandible (OR = 1.49; p  = 0.007), teeth with short length of root filling (OR = 4.08; p  < 0.001), overfilled teeth (OR = 2.99; p  = 0.001), and teeth with inadequate density of root filling (OR = 4.14; p  < 0.001). Considering variables related to coronal restoration, neither coronal restoration type nor quality was found to be predictive for posttreatment AP. Merely, the presence of intracanal post significantly increased the odds of AP presence (OR = 1.57; p  = 0.009).

Conclusion  The results of the present study did not indicate that type or quality of coronal restoration may be predictors of posttreatment AP. Periapical disease was significantly associated with molars, mandibular teeth, substandard quality of root fillings, and intracanal post presence.

Trends of endodontic and periapical status in adult Danish populations from 1997 to 2009: A repeated cross-sectional study

AIM

To compare the endodontic and periapical status of two similar adult Danish populations examined in 1997-1998 and 2007-2009, respectively.

METHODOLOGY

Two populations from Aarhus County, Denmark (age range: 20-64 years) were randomly selected using the Danish Civil Registration System. Full-mouth intraoral radiographs (14 periapical, 2 bitewing) of 616 individuals in 1997-1998 (C1: 16 018 teeth) and 398 individuals in 2007-2009 (C2: 10 668 teeth) were taken to ascertain the number of teeth, presence of root fillings (RFs) and apical periodontitis (AP) using the periapical index (PAI). T-tests with unequal variances were used to assess differences between C1 and C2 with respect to age and the number of teeth. Multivariable and multinomial logistic regression analyses were used to assess the effect of cohort, age and tooth type on the prevalence and relative frequency of RFs and AP.

RESULTS

Mean age and mean number of teeth were higher in C2 than C1 (age; C1: 42.3 years, C2: 44.6 years; p = .003), (teeth; C1: 26.0, C2: 26.8; p < .001). The prevalence of root filled teeth was lower in C2 than C1 (C1: 51.8%, C2: 45.0%; p = .03); however, the prevalence of AP was similar (C1: 42.0%, C2: 45.0%). The relative frequency of root filled teeth was lower in C2 than C1 (C1: 4.8%, C2: 3.6%; p = .004), although the individuals were older in C2. The relative frequency of AP was similar in the two cohorts (C1: 3.3%, C2: 3.6%; p = .42). The relative frequency of AP in non-root filled teeth doubled from 0.9% in C1 to 1.8% in C2. C2 had higher PAI scores than C1 for root filled and non-root filled teeth, despite age correction (p ≤ .0007).

CONCLUSIONS

Two similar general Danish populations examined, respectively, in 1997-1998 and 2007-2009, were associated with a decreasing trend in the prevalence and relative frequency of RFs over the decade. There was no difference in relative frequency of AP in root filled teeth, but an increase in relative frequency of AP in non-root filled teeth. Further population-based studies including analysis of non-root filled teeth using the full-scale PAI and quality assessment of restorations are recommended.

Prevalence of periapical lesions, root canal treatments and restorations in teeth adjacent to implant- or tooth-supported crowns: A multi-centre cross-sectional study

AIM

To describe the prevalence of periapical lesions, root canal treatments and coronal restorations on teeth adjacent to either implant- or natural tooth-supported crowns using cone-beam computed tomography (CBCT) assessment compared to nonadjacent teeth.

METHODOLOGY

A total of 1249 CBCT volumes were screened by five pre-calibrated observers in 11 health centres. A step-by-step screening protocol was implemented and reviewed every 3 months, and mandatory setting characteristics were established for all CBCT scans using dedicated visualization software. Intra- and inter-rater reliability tests were conducted. The prevalence of periapical lesions, root canal treatments and coronal restorations was recorded on both teeth adjacent and nonadjacent to implant- (predictor 1) or natural tooth-supported crowns (predictor 2). A binary logistic model (Generalizing Estimating Equations test) was used to verify whether the prevalence of periapical lesion, root canal filling and the tooth restorative status are altered when the assessed tooth is adjacent or not to an implant-supported crown (predictor 1); or to a natural tooth-supported crown (predictor 2). Odds ratio and confidence intervals for the dependent variables at both predictors were obtained. The significance level was set at .05.

RESULTS

A global sample of 22 899 teeth was included. Compared to nonadjacent teeth, the prevalence of periapical lesion, root canals treatments and restorative procedures when adjacent to implant-supported crowns was 10.7%, 19.6% and 22.9% higher, respectively, and when adjacent to tooth-supported crowns was 19.3%, 35.6% and 37.4% higher respectively. These results were significant only for variables root canal filling and coronal restoration (p < .0001). Odds ratio to present root canal treatment is 2.57 times higher (CI 1.95-3.39, p = .0001) when the tooth is adjacent to implant-supported crown and 4.39 times (CI 3.49-5.53, p = .0001) when adjacent to tooth-supported crown, whilst for restorative procedure, the odds are, respectively, 1.63 (CI 1.29-2.06, p = .0001) and 2.30 (CI 1.92-2.76, p = .0001).

CONCLUSIONS

Teeth adjacent to both implant- and natural tooth-supported crowns were associated with a higher frequency of root canal filling and coronal restorations.

Calibration improves observer reliability in detecting periapical pathology on panoramic radiographs

OBJECTIVE

To determine whether calibration improves observer reliability when assessing DMFT-score, root-filled teeth and periapical lesions on panoramic radiographs.

MATERIAL AND METHODS

A sample of 100 panoramic radiographs was selected from a cohort of myocardial infarction patients (n = 797) and matched controls (n = 796). The following variables were assessed: DMFT-score, remaining teeth, root-filled teeth and periapical lesions. Two specialists, an endodontist and a radiologist, served as reference examiners and undertook two separate assessments. Disagreement cases were jointly assessed and the final results were used as the reference standard. Three observers undertook three separate assessments, the first without prior training, the second after calibration against the reference standard and the third with the sample concealed in the complete material. Statistical analysis was made with Wilcoxon Signed rank test and Sign test. Agreement was calculated as Intraclass Correlation Coefficient (ICC) (95% CI) and Weighted Kappa (κ) (95% CI).

RESULTS

Periapical lesions disclosed high inter-observer variability for the reference examiners and diverged significantly between the observers and the reference standard. For the reference examiners, inter-observer agreement was κ = 0.53. The observers, in their first assessments had κ values ranging from 0.22 to 0.60 in relation to the reference standard. Following calibration, the κ values increased, ranging from 0.59 to 0.80. For the third assessment, the κ values ranged from 0.54 to 0.75. DMFT-score, remaining teeth and root-filled teeth disclosed high reliability throughout all assessments (ICC = 0.88-0.98 and κ = 0.98-0.99).

CONCLUSIONS

DMFT-score, remaining teeth and root-filled teeth can be reliably assessed on panoramic radiographs. Calibration against a reference standard improves observer reliability in the detection of periapical lesions.

Artificial Intelligence in Endodontics: Current Applications and Future Directions

INTRODUCTION

Artificial intelligence (AI) has the potential to replicate human intelligence to perform prediction and complex decision making in health care and has significantly increased its presence and relevance in various tasks and applications in dentistry, especially endodontics. The aim of this review was to discuss the current endodontic applications of AI and potential future directions.

METHODS

Articles that have addressed the applications of AI in endodontics were evaluated for information pertinent to include in this narrative review.

RESULTS

AI models (eg, convolutional neural networks and/or artificial neural networks) have demonstrated various applications in endodontics such as studying root canal system anatomy, detecting periapical lesions and root fractures, determining working length measurements, predicting the viability of dental pulp stem cells, and predicting the success of retreatment procedures. The future of this technology was discussed in light of helping with scheduling, treating patients, drug-drug interactions, diagnosis with prognostic values, and robotic-assisted endodontic surgery.

CONCLUSIONS

AI demonstrated accuracy and precision in terms of detection, determination, and disease prediction in endodontics. AI can contribute to the improvement of diagnosis and treatment that can lead to an increase in the success of endodontic treatment outcomes. However, it is still necessary to further verify the reliability, applicability, and cost-effectiveness of AI models before transferring these models into day-to-day clinical practice.

CBCT influences endodontic therapeutic decision-making in immature traumatized teeth with suspected pulp necrosis: a before-after study

OBJECTIVE

To evaluate the impact of cone-beam computed tomography (CBCT) in endodontic therapeutic decision-making of immature traumatized teeth with suspected pulp necrosis.

METHODS

Over two years, consecutive patients with a dental trauma in their front teeth (apex >0.5 mm) and with suspected pulp necrosis based on clinical and radiographic findings were referred to a specialist clinic in Sweden. Fifteen patients aged 6-13 (18 teeth) were included and clinically examined by an endodontist. Intraoral radiographs and CBCT examinations were obtained. Five practitioners, three endodontists and two residents in endodontics, used these examinations to determine the most appropriate treatment for the 18 cases (all central incisors) on two occasions scheduled 19 weeks apart. On the first occasion, the practitioners had access to clinical information and the intraoral radiographs ('before' CBCT); on the second occasion, the practitioners had also access to a radiologist report and the CBCT images ('after' CBCT). Their treatment plans - no treatment, watchful waiting, endodontic orthograde treatment, or extraction - were made anonymously and independently. Results were analysed using descriptive statistics and Wilcoxon signed-rank test.

RESULTS

'After' CBCT, practitioners changed treatment plans in 30% of the 90 assessments, 74% of which were more aggressive (p = 0.028). In 49% of the assessments, practitioners who chose the watchful and waiting treatment plan 'before' CBCT changed to a more aggressive therapy such as endodontic orthograde treatment and extraction 'after' CBCT (p = 0.005).

CONCLUSION

This study provides evidence that CBCT influences endodontic therapeutic decision-making regarding immature traumatised teeth with suspected pulp necrosis, chiefly when expectant management (i.e., watchful and waiting) was selected before access to CBCT.

Conservative Approach in the Management of Large Periapical Cyst-Like Lesions. A Report of Two Cases

Background and Objectives: Periapical cystic lesions are a pathology frequently addressed to endodontic specialists. Although their therapy is still not standardized, the treatment should be as conservative as possible and by endodontic means, as they are lesions of endodontic origin. The present case report describes two cases of upper central incisors with large cyst-like periapical lesions, and their one-year follow up. Materials and Methods: Endodontic orthograde treatment was performed under copious irrigation with sodium hypochlorite, in association with calcium hydroxide as an intra-canal medication for both teeth. Root canal filling was achieved in a separate appointment using the continuous wave of condensation technique. A decompression procedure was used in association with endodontic therapy in the second case to reduce the pressure inside the cystic lesion and to allow its drainage, and only because the root canal could not be dried three weeks after medication. Initial cone beam computed tomography (CBCT) investigations, as well as at the one-year follow up, were used to compare the evolution of the lesion. Results: Both cases had a favorable outcome. New bone formation in the periapical region and complete resolution of the lesion was observed at the one-year control in the first case. In the second case, although the lesion was still not completely healed at 12 months, a significant reduction in its size could be observed, showing active signs of healing. Conclusions: Endodontic treatment is the first choice option in the management of teeth with pulpal necrosis and large periapical cystic-like lesions. Decompression is the only surgical procedure recommended when the canals cannot be dried and obturated. Large surgical interventions are unnecessary in cases where endodontic treatment can be performed.

Effect of a formalin-based fixation method on bone mineral content in human ex-vivo specimens

OBJECTIVE

Histopathology of formalin-fixated human ex-vivo specimens may be used as reference standard for evaluation of diagnostic index tests like CBCT or MRI. The aim was to estimate changes in bone mineral content (BMC) over time in human ex-vivo bone specimens fixated in a formalin-based solution for 24 h followed by storage in an alcohol-based medium for six months, assessed by dual-energy X-ray absorptiometry (DXA).

METHODOLOGY

Bone specimens (n = 19) from human ex-vivo mandibles donated for science were included. BMC was measured by DXA before fixation (D₀), after 24 h of immersion fixation in a formalin-based solution (D₁), and hereafter every 30 days (M₁-M₆) during storage in a 30% ethanol-based storage medium for 6 months. Changes in BMC from D₀ to D₁ and from D₀ to M₆ were calculated and mean change in BMC estimated.

RESULTS

Mean change in BMC from D₀ to D₁ was -0.73% (95% CI -1.75%; 0.29%), and from D₀ to M₆ -1.19% (95% CI -2.14%; -0.23%).

CONCLUSIONS

No changes in BMC of ex-vivo human bone specimens were found after 24 h formalin-based immersion fixation. After six months storage in an ethanol-based medium, BMC mean loss of 1% was detected. In this range, changes in BMC are not clinically relevant.

Outcome measures to assess the effectiveness of endodontic treatment for pulpitis and apical periodontitis for use in the development of European Society of Endodontology (ESE) S3 level clinical practice guidelines: a protocol

The European Society of Endodontology (ESE) is in the process of developing S3Level Clinical Practice Guidelines for the treatment of pulpal and apical disease for the benefit of clinicians and patients. In order to ensure a homogenous review process in the development of the clinical practice guidelines, it is essential that the core outcomes for all endodontic treatments are standardized and recommendations are made regarding minimum follow-up time specific to each outcome measure. In the absence of a recognized core outcome set in Endodontics, the current project aimed to follow an established consensus process to define the most appropriate clinician and patient-reported outcomes. As part of the project, recommendations will also be agreed regarding an acceptable minimum follow-up period for studies by literature review and group discussion. The selected outcome measures and follow-up periods will be used in subsequent systematic analyses of the literature to investigate the effectiveness of endodontic treatment to alleviate pulpitis and apical periodontitis. In this paper, previous reviews, ESE Guidelines and Position Statements were searched in order to compile a list of potentially important outcome measures for the treatment of pulpitis (working group 1), the nonsurgical treatment of apical periodontitis (working group 2), the surgical treatment of apical periodontitis (working group 3) and the regenerative treatment of apical periodontitis (working group 4). Initially, the two S3 guideline leads selected two independent senior clinical academics with experience of evidence-based dentistry to lead each of the four working groups forming a 10-member steering group. The working group leads in turn selected 32 academics with experience of evidence-based dentistry to lead the individual systematic reviews contained within the respective working groups. These 42 individuals make up the Guideline Development Group (GDG). Prior to the selected systematic reviewers commencing writing and submitting the review protocol, the complete list of outcome variables identified in this document will be ranked by the 42 members of the GDG in their importance to the individual patient using a 9-point Likert scale. A summary of the survey scores will thereafter be shared with the members of the group and the final list of clinician and patient-reported outcome measures rated as critical for decision making (7-9 on Likert scale by majority of survey participants) to guide systematic reviews will be consented and confirmed during an online meeting of the steering group. In this online meeting, another aspect with regard to meaningfulness of clinical trial results to be addressed in systematic reviews will be consented: length of follow-up. In order to develop high quality guidelines, it is suggested that the follow-up period after treatment should be related to the specific outcome measure being addressed; however, a minimum of one year for assessing the effectiveness of treatments for pulpitis and apical periodontitis should be considered. It is accepted, that selected research questions that focus on pain, swelling, medication taken or investigating diagnostic accuracy are likely to have shorter follow-up periods. As a result of the GDG consensus process, the outcome measures and length of follow-up will, alongside the use of standard instruments to assess the methodological quality of clinical trials and other comparative studies, be applied to all the commissioned systematic reviews that will inform the subsequent process when developing the ESE S3 Level Clinical Practice Guidelines.

Endodontic disease detection: digital periapical radiography versus cone-beam computed tomography-a systematic review

Purpose: To assess the comparative diagnostic performance of digital periapical (PA) radiography and cone-beam computed tomography (CBCT) imaging on endodontic disease detection and to provide study methodology and design recommendations for future studies comparing the diagnostic performance of imaging modalities on endodontic disease detection. Approach: A search of the Medline, Embase, Scopus, Web of Science, and the Cochrane Central Register of Controlled Trials databases was conducted. Studies that compared the performance of CBCT to digital PA radiography for detecting endodontic disease had an independent reference standard determining the presence of endodontic disease and conducted data analysis including either sensitivity, specificity, receiver operating characteristic (ROC) analysis or free response operating characteristic analysis were included. Of the 20,530 identified studies, only 3 fulfilled the inclusion criteria. Results: Most studies assessed for eligibility were excluded due to limitations and biases in study design-15 of 18 studies had no reference standard. Only one retrospective clinical study reported on the diagnostic performance of CBCT and showed a sensitivity of 86% and specificity of 26%. Two cadaver studies reported sensitivity ranging from 60% to 100%, specificity ranging from 79% to 100%, and an area under the ROC curve of 0.943 for CBCT. The reported sensitivity for digital PA radiography ranged from 27% to 60%, specificity was 99%, and the area under the ROC curve was 0.629. Conclusions: There is a lack of quality evidence and insufficient data to compare diagnostic performance of digital PA and CBCT imaging. This emphasizes the need for well-designed studies to inform clinicians about the relative diagnostic performance of these imaging modalities.

Comparative analysis of different periapical index systems used in cone-beam computed tomography

This study aimed to compare the three index systems designed for cone-beam computed tomography (CBCT) in terms of intra- and inter-observer agreement. 117 root-filled teeth with or without periapical radiolucency from 77 of already existing CBCT images were chosen randomly. Two observers evaluated the periapical status of the selected teeth and graded the scores twice using CBCT periapical index (CBCTPAI), endodontic radiolucency index (ERI) and complex periapical index (COPI) part of the periapical and endodontic status scale (PESS), respectively. The researchers' self-agreement kappa values ranged from substantial to almost perfect. A moderate inter-observer agreement was present for the COPI and ERI, whereas a fair agreement was present for CBCTPAI. The researchers' ICC for the inter-observer reliability of CBCTPAI, ERI and COPI was 0.75, 0.77 and 0.80, respectively. COPI had the highest self-agreement and inter-observer reliability. ERI showed the highest intra-observer variation, whereas CBCTPAI showed the highest inter-observer variation.

The global prevalence of apical periodontitis: a systematic review and meta-analysis

BACKGROUND

Apical periodontitis (AP) frequently presents as a chronic asymptomatic disease. To arrive at a true diagnosis, in addition to the clinical examination, it is mandatory to undertake radiographic examinations such as periapical or panoramic radiographs, or cone-beam computed tomography (CBCT). Thus, the worldwide burden of AP is probably underestimated or unknown. Previous systematic reviews attempted to estimate the prevalence of AP, but none have investigated which factors may influence its prevalence worldwide.

OBJECTIVES

To assess: (i) the prevalence of AP in the population worldwide, as well as the frequency of AP in all teeth, nontreated teeth and root filled teeth; (ii) which factors can modify the prevalence of AP.

METHODS

A search was conducted in the PubMed-MEDLINE, EMBASE, Cochrane-CENTRAL, LILACS, Google scholar and OpenGrey databases, followed by hand searches, until September 2019. Cross-sectional, case-control and cohort studies reporting the prevalence of AP in humans, using panoramic or periapical radiograph or CBCT as image methods were included. No language restriction was applied. An adaptation of the Newcastle-Ottawa Scale was used to evaluate the quality of the studies. A meta-analysis was performed to determine the pooled prevalence of AP at the individual level. Secondary outcomes were the frequency of AP in all teeth, nontreated teeth and rootfilled teeth. Subgroup analyses using random-effect models were carried out to analyse the influence of explanatory covariables on the outcome.

RESULTS

The search strategy identified 6670 articles, and 114 studies were included in the meta-analysis, providing data from 34 668 individuals and 639 357 teeth. The prevalence of AP was 52% at the individual level (95% CI 42%-56%, I²  = 97.8%) and 5% at the tooth level (95% CI 4%-6%; I²  = 99.5%). The frequency of AP in root-filled teeth and nontreated teeth was 39% (95% CI 36%-43%; I²  = 98.5%) and 3% (95% CI 2%-3%; I²  = 99.3%), respectively. The prevalence of AP was greater in samples from dental care services (DCS; 57%; 95% CI 52%-62%; I²  = 97.8%) and hospitals (51%; 95% CI 40%-63%; I²  = 95.9%) than in those from the general population (GP; 40%; 95% CI 33%-46%; I²  = 96.5%); it was also greater in people with a systemic condition (63%; 95% CI 56%-69%, I²  = 89.7%) compared to healthy individuals (48%; 95% CI 43%-53%; I²  = 98.3%).

DISCUSSION

The subgroup analyses identified explanatory factors related to the variability in the prevalence of AP. However, the high clinical heterogeneity and high risk of bias across the primary studies indicate that the findings must be interpreted with caution.

CONCLUSIONS

Half of the adult population worldwide have at least one tooth with apical periodontitis. The prevalence of AP is greater in samples from the dental care services, but it is also high amongst community representative samples from the general population. The present findings should bring the attention of health policymakers, medical and dental communities to the hidden burden of endodontic disease in the population worldwide.

Accuracy of Microcomputed Tomography in Detecting Dentinal Cracks: A Correlative Study with Scanning Electron and Operative Microscopy

The aim of the study was to evaluate the accuracy of microcomputed tomography (mCT) to detect dentinal cracks when compared with scanning electron microscopy (SEM) and operating microscopy (OM). Different conditions of pixel size (10 or 17 μm), sample moisture (dry/moist), and transillumination (with/without) were evaluated. Additionally, the influence of the dentinal defect width on its detection was analyzed. The root canals of human mandibular incisors were prepared with the Reciproc R40 instrument (VDW, Munich, Germany). The roots were sectioned 5 and 10 mm from the apex, and mCT scans of middle and apical segments were performed at two pixel sizes: 10 μm and 17 μm, under dry and moist conditions (groups: 10dry, 10moist, 17dry, and 17moist). The operating microscope was used with and without transillumination (groups: OMTrans and OM). Findings showed that accuracy was moderate for the 10dry, 10moist, and OMTrans groups, poor for OM and very poor for 17dry and 17moist. The thickness of the dentin crack significantly influenced its detection by mCT using the resolution of 10 μm in both dry and wet conditions (P = .002), 17 μm in the dry condition (P = .002), and by the operating microscope using transillumination (P = .009). Some cracks visualized in SEM were not detected by mCT and an operating microscope. Not only the mCT resolution but also the sample moisture condition and the dentinal crack width can significantly influence its detection.

Do different cone beam computed tomography exposure protocols influence subjective image quality prior to and after root canal treatment?

Objectives

The current study aimed to evaluate different CBCT exposure protocols and influencing factors affecting the subjective image quality of scans taken for endodontic indications.

Materials and methods

Twelve extracted teeth, comprising of two sets of maxillary molars, premolars, canines and incisors, mandibular premolars, and molars, were endodontically treated, and either received a fiber or metal post. The teeth were scanned by CBCT imaging before and after root canal treatment, and after post insertion. Each scan was performed thrice, using an ultra low dose (ULD), standard (SM), and high-resolution mode (HR), respectively. Twelve observers—4 endodontists, 4 periodontists, and 4 radiologists—assessed the subjective image quality using visual analogue scales (VAS). Potential influencing factors were evaluated including acquisition mode, observer specialty, stage of treatment, type of post, and type of tooth, using one-way ANOVA and T test.

Results

Teeth scanned with the ULD had the highest average VAS score (72.5), followed by HR (70.2), and SM (69.0) for values pooled from all teeth and observers. CBCT acquisition mode was not a significant influencing factor on the VAS scores. Observer specialty, stage of treatment, type of post, and type of tooth were significant influencing factors.

Conclusions

Based on the present in vitro data, a low-dose CBCT mode seems not to negatively affect the perception of image quality.

Clinical relevance

The findings from this in vitro study demonstrate that a low-dose CBCT mode might have potential for diagnostics prior to or following endodontic treatment.

High resolution MRI for quantitative assessment of inferior alveolar nerve impairment in course of mandible fractures: an imaging feasibility study

The purpose of this study was to evaluate a magnetic resonance imaging (MRI) protocol for direct visualization of the inferior alveolar nerve in the setting of mandibular fractures. Fifteen patients suffering from unilateral mandible fractures involving the inferior alveolar nerve (15 affected IAN and 15 unaffected IAN from contralateral side) were examined on a 3 T scanner (Elition, Philips Healthcare, Best, the Netherlands) and compared with 15 healthy volunteers (30 IAN in total). The sequence protocol consisted of a 3D STIR, 3D DESS and 3D T1 FFE sequence. Apparent nerve-muscle contrast-to-noise ratio (aNMCNR), apparent signal-to-noise ratio (aSNR), nerve diameter and fracture dislocation were evaluated by two radiologists and correlated with nerve impairment. Furthermore, dislocation as depicted by MRI was compared to computed tomography (CT) images. Patients with clinically evident nerve impairment showed a significant increase of aNMCNR, aSNR and nerve diameter compared to healthy controls and to the contralateral side (p < 0.05). Furthermore, the T1 FFE sequence allowed dislocation depiction comparable to CT. This prospective study provides a rapid imaging protocol using the 3D STIR and 3D T1 FFE sequence that can directly assess both mandible fractures and IAN damage. In patients with hypoesthesia following mandibular fractures, increased aNMCNR, aSNR and nerve diameter on MRI imaging may help identify patients with a risk of prolonged or permanent hypoesthesia at an early time.

Artificial Intelligence for the Computer-aided Detection of Periapical Lesions in Cone-beam Computed Tomographic Images

INTRODUCTION

The aim of this study was to use a Deep Learning (DL) algorithm for the automated segmentation of cone-beam computed tomographic (CBCT) images and the detection of periapical lesions.

METHODS

Limited field of view CBCT volumes (n = 20) containing 61 roots with and without lesions were segmented clinician dependent versus using the DL approach based on a U-Net architecture. Segmentation labeled each voxel as 1 of 5 categories: "lesion" (periapical lesion), "tooth structure," "bone," "restorative materials," and "background." Repeated splits of all images into a training set and a validation set based on 5-fold cross validation were performed using Deep Learning segmentation (DLS), and the results were averaged. DLS versus clinical-dependent segmentation was assessed by dichotomized lesion detection accuracy evaluating sensitivity, specificity, positive predictive value, negative predictive value, and voxel-matching accuracy using the DICE index for each of the 5 labels.

RESULTS

DLS lesion detection accuracy was 0.93 with specificity of 0.88, positive predictive value of 0.87, and negative predictive value of 0.93. The overall cumulative DICE indexes for the individual labels were lesion = 0.52, tooth structure = 0.74, bone = 0.78, restorative materials = 0.58, and background = 0.95. The cumulative DICE index for all actual true lesions was 0.67.

CONCLUSIONS

This DL algorithm trained in a limited CBCT environment showed excellent results in lesion detection accuracy. Overall voxel-matching accuracy may be benefited by enhanced versions of artificial intelligence.

Association between Endodontically Treated Maxillary and Mandibular Molars with Fused Roots and Periapical Lesions: A Cone-beam Computed Tomography Cross-sectional Study

INTRODUCTION

Fused root variations of the root canal system increase the complexity of the inner root canal system anatomy. The aim of the present study was to determine, in in vivo conditions, the proportion of periapical lesions in association with endodontically treated maxillary and mandibular molars with fused roots presenting previous root canal treatment by assessing preexisting data via cone-beam computed tomographic volumes.

METHODS

A total of 1160 CBCT scans with an overall sample of 20,836 teeth were screened. A global count of 3701 maxillary molars and mandibular second molars were included in the study. The Cohen kappa test and interclass correlation coefficient tested the intra- and interrater reliability, respectively. The percentage of periapical lesions associated with molars with or without root fusion was determined. Proportions were expressed with 95% confidence intervals (CIs). The z test for proportions was used to analyze differences between subgroups, and an odds ratio was calculated in order to understand the association between periapical lesions and root configuration.

RESULTS

Fused molars presented a prevalence of periapical lesions in endodontically treated teeth of 74.0% (95% CI, 65.2%-82.8%), whereas nonfused molars had a proportion of periapical lesions in root canal-treated teeth of 69.5% (95% CI, 65.2%-73.8%; P > .05). Endodontically treated molars with fused roots presented with 1.3 higher odds of being associated with periapical lesions than endodontically treated molars with nonfused roots.

CONCLUSIONS

A tendency of a higher proportion of periapical lesions was found in the fused rooted molars with a history of root canal treatment when compared with nonfused teeth; however, no statistically significant difference was noted.