The Recommendation of Cone-beam Computed Tomography and Its Effect on Endodontic Diagnosis and Treatment Planning

DentalSegmentator: Robust open source deep learning-based CT and CBCT image segmentation

OBJECTIVES

Segmentation of anatomical structures on dento-maxillo-facial (DMF) computed tomography (CT) or cone beam computed tomography (CBCT) scans is increasingly needed in digital dentistry. The main aim of this research was to propose and evaluate a novel open source tool called DentalSegmentator for fully automatic segmentation of five anatomical structures on DMF CT and CBCT scans: maxilla/upper skull, mandible, upper teeth, lower teeth, and the mandibular canal.

METHODS

A retrospective sample of 470 CT and CBCT scans was used as a training/validation set. The performance and generalizability of the tool was evaluated by comparing segmentations provided by experts and automatic segmentations in two hold-out test datasets: an internal dataset of 133 CT and CBCT scans acquired before orthognathic surgery and an external dataset of 123 CBCT scans randomly sampled from routine examinations in 5 institutions.

RESULTS

The mean overall results in the internal test dataset (n = 133) were a Dice similarity coefficient (DSC) of 92.2 ± 6.3 % and a normalised surface distance (NSD) of 98.2 ± 2.2 %. The mean overall results on the external test dataset (n = 123) were a DSC of 94.2 ± 7.4 % and a NSD of 98.4 ± 3.6 %.

CONCLUSIONS

The results obtained from this highly diverse dataset demonstrate that this tool can provide fully automatic and robust multiclass segmentation for DMF CT and CBCT scans. To encourage the clinical deployment of DentalSegmentator, the pre-trained nnU-Net model has been made publicly available along with an extension for the 3D Slicer software.

CLINICAL SIGNIFICANCE

DentalSegmentator open source 3D Slicer extension provides a free, robust, and easy-to-use approach to obtaining patient-specific three-dimensional models from CT and CBCT scans. These models serve various purposes in a digital dentistry workflow, such as visualization, treatment planning, intervention, and follow-up.

Construction and Evaluation of an AI-based CBCT Resolution Optimization Technique for Extracted Teeth

INTRODUCTION

In dental clinical practice, cone-beam computed tomography (CBCT) is commonly used to assist practitioners to recognize the complex morphology of root canal systems; however, because of its resolution limitations, certain small anatomical structures still cannot be accurately recognized on CBCT. The purpose of this study was to perform image super-resolution (SR) processing on CBCT images of extracted human teeth with the help of a deep learning model, and to compare the differences among CBCT, super-resolution computed tomography (SRCT), and micro-computed tomography (Micro-CT) images through three-dimensional reconstruction.

METHODS

The deep learning model (Basicvsr++) was selected and modified. The dataset consisted of 171 extracted teeth that met inclusion criteria, with 40 maxillary first molars as the training set and 40 maxillary first molars as well as 91 teeth from other tooth positions as the external test set. The corresponding CBCT, SRCT, and Micro-CT images of each tooth in test sets were reconstructed using Mimics Research 17.0, and the root canal recognition rates in the 3 groups were recorded. The following parameters were measured: volume of hard tissue (V1), volume of pulp chamber and root canal system (V2), length of visible root canals under orifice (VL-X, where X represents the specific root canal), and intersection angle between coronal axis of canal and long axis of tooth (∠X, where X represents the specific root canal). Data were statistically analyzed between CBCT and SRCT images using paired sample t-test and Wilcoxon test analysis, with the measurement from Micro-CT images as the gold standard.

RESULTS

Images from all tested teeth were successfully processed with the SR program. In 4-canal maxillary first molar, identification of MB2 was 72% (18/25) in CBCT group, 92% (23/25) in SRCT group, and 100% (25/25) in Micro-CT group. The difference of hard tissue volume between SRCT and Micro-CT was significantly smaller than that between CBCT and Micro-CT in all tested teeth except 4-canal mandibular first molar (P < .05). Similar results were obtained in volume of pulp chamber and root canal system in all tested teeth (P < .05). As for length of visible root canals under orifice, the difference between SRCT and Micro-CT was significantly smaller than that between CBCT and Micro-CT (P < .05) in most root canals.

CONCLUSIONS

The deep learning model developed in this study helps to optimize the root canal morphology of extracted teeth in CBCT. And it may be helpful for the identification of MB2 in the maxillary first molar.

The outcome of combined use of iRoot BP Plus and iRoot SP for root-end filling in endodontic microsurgery: a randomized controlled trial

OBJECTIVES

Root-end filling is important for the clinical outcome of endodontic microsurgery. Our previous study showed that combined application of iRoot BP Plus Root Repair Material (BP-RRM) and iRoot SP Injectable Root Canal Sealer (SP-RCS) in root-end filling exhibited better apical sealing as compared to the application of BP-RRM alone. The aim of this randomized controlled clinical trial was to evaluate the effect of the combined use of BP-RRM and SP-RCS on the prognosis of teeth with refractory periapical diseases after endodontic microsurgery.

MATERIALS AND METHODS

240 teeth with refractory periapical diseases scheduled for endodontic microsurgery were randomly divided into BP-RRM/SP-RCS group (n = 120) and BP-RRM group (n = 120). The patients were followed up at 3 months, 6 months, and 12 months after endodontic microsurgery. Pre- and post-operative clinical and radiographic examinations were performed to evaluate the treatment outcome. The 1-year success rate of endodontic microsurgery in BP-RRM/SP-RCS and BP-RRM groups was compared by Chi-square test. Factors that might impact the prognosis were further analyzed using Chi-square test or Fisher's exact test.

RESULTS

A total of 221 teeth completed the 12-month follow-up. The 1-year success rates of the BP-RRM/SP-RCS and BP-RRM groups were 94.5% (104/110) and 92.8% (103/111), respectively. The combined use of BP-RRM and SP-RCS achieved a clinical outcome comparable to BP-RRM alone (P = 0.784). Tooth type (P = 0.002), through-and-through/apico-marginal lesion (P = 0.049), periodontal status (P < 0.0001), and Kim's lesion classification (P < 0.0001) were critical factors associated with the 1-year success of endodontic microsurgery.

CONCLUSIONS

The combined use of BP-RRM and SP-RCS is a practicable method for root-end filling in endodontic microsurgery with a satisfactory 1-year clinical outcome.

CLINICAL RELEVANCE

The combined application of BP-RRM and SP-RCS in EMS is an effective root-end filling method with a satisfactory 1-year clinical outcome.

TRIAL REGISTRATION

This study was registered in the Chinese Clinical Trial Registry (ChiCTR2100052174).

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.

Cone-beam computed tomography-Predictors and characteristics of usage in Australia and New Zealand, a multifactorial analysis

Cone-beam computed tomography (CBCT) is an increasingly used imaging modality. This study aimed to identify the factors that predict its usage amongst endodontists in Australia and New Zealand and describe usage characteristics. Data were collected via an online questionnaire, with analysis including descriptive statistics, cross-tabulation and multifactorial modelling. Ninety-four endodontists completed the questionnaire who were using CBCT for 7 years (median), over half had a CBCT unit in practice, with most prescribing up to 10 scans/month and 55 using a small field of view. Sixty-eight participated in >5 h of CBCT education/year and a third received a specialist-prepared report. The number of prescriptions/month was significantly associated with on-site CBCT units (Exp B: 8.53; 95% CI: 1.46-49.86, p < 0.05) and the number of years of CBCT usage by participants (Exp B: 1.46; 95% CI: 1.17-1.84, p = 0.001). CBCT imaging in endodontics is a useful diagnostic aid to decision making and treatment planning, with widespread acceptance and usage.

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.

Current status of cone-beam computed tomography teaching in Brazilian undergraduate endodontic programs - A web-based survey

PURPOSES

This study aimed to assess the current status of cone-beam computed tomography (CBCT) education in Brazilian undergraduate Endodontic programs.

METHODS

One hundred program directors were emailed. The questionnaire asked whether the CBCT topic was included in the program, the availability of a CBCT machine, and, the total length of the dental program. For the group that does not teach, seven questions discussed the reasons for not teaching and whether another subject included this topic. For the programs that included CBCT, seven questions discussed the number of hours included, and the impression of the program directors with the quality of the teaching. The chi-square test was used for the correlation between the availability of the CBCT machine and the length of the dental program with the inclusion of the topic.

RESULTS

Thirty-five program directors replied to the questionnaire. Twenty-six (74.3%) reported that the topic of CBCT is not included in their programs. There was no impact of the availability of a CBCT machine on the inclusion of the topic (p > 0.05). The increased length of the dental program decreased the inclusion of the topic (p < 0.05). Fifty percent of the directors replied that lack of time is the reason for not including the topic. Among the programs that include CBCT, the majority (55.6%) deliver 3-5 h of lectures. The practical activities range from 1 to 5 h or more. The majority (77.8%) of the directors are satisfied with the content delivered and 44.4% understand that the students are competent in the interpretation of CBCT images.

CONCLUSIONS

The majority of the Endodontic undergraduate programs in Brazil do not include CBCT in the program. The availability of a CBCT machine does not impact the inclusion of the topic, the increased duration of the dental program decreases the inclusion of the CBCT topic.

Global Prevalence of Maxillary Sinusitis of Odontogenic Origin and Associated Factors: A Systematic Review and Meta-Analysis

INTRODUCTION

The overall prevalence of maxillary sinusitis of odontogenic origin (MSOO) is still unknown. Therefore, this study aimed to determine the pooled prevalence of MSOO and verify associations between different odontogenic conditions and MSOO.

METHODS

Six electronic databases and the gray literature were searched on August 25, 2022. Two independent reviewers selected observational studies reporting the prevalence of MSOO and associated conditions in adults. Studies that did not use computed tomography for diagnosis were excluded. The methodological quality of the studies was assessed using the Joanna Briggs Institute Critical Appraisal Checklist for Cross-Sectional Studies. Data were analyzed by proportion and association meta-analyses. The certainty of evidence was assessed using the Grading of Recommendations Assessment, Development and Evaluation approach.

RESULTS

Thirty-eight studies were included in the qualitative analysis and thirty-one in the meta-analyses. Only 12 studies (31.6%) fulfilled all items of the methodological quality checklist. Overall, the studies reported prevalence measures per maxillary sinus or patient. Thus, the pooled prevalence of MSOO was 51% per sinus (95% confidence interval [CI] [40%-61%]) and 50% per patient (95% CI [41%-59%]). Apical lesion (odds ratio [OR]: 4.03, 95% CI [2.26-7.19]), periodontitis (OR: 5.49, 95% CI [2.27-13.24]), moderate (OR: 2.57, 95% CI [1.85-3.57]) and severe bone loss (OR: 13.80, 95% CI [2.81-67.85] were significantly associated with MSOO. The certainty of the evidence for the associations was very low.

CONCLUSIONS

The pooled prevalence of MSOO on computed tomography assessment was 51% per maxillary sinus and 50% per patient. Therefore, half of the maxillary sinusitis may be of odontogenic origin. Apical lesion, periodontitis, and moderate and severe bone loss were significantly associated with MSOO.

Patient-centric outcome assessment of endodontic microsurgery using periapical radiography versus cone beam computed tomography: A randomized clinical trial

AIM

This study aimed to evaluate whether utilizing additional cone beam computed tomography (CBCT) imaging has any effect on quality of life and healing outcome following periapical surgery compared with periapical radiographs (PR).

METHODOLOGY

The study was registered in ClinicalTrials.gov (NCT04333940). In this parallel group randomized controlled trial, 52 patients (88 teeth) with persistent apical periodontitis and periapical radiographic evidence of periapical lesion were randomly assigned to either PR or CBCT group. The primary predictor was the type of the imaging method (PR only or with additional CBCT). The primary outcome was patient's quality of life during the first week after periapical surgery and the secondary outcomes were duration of surgery and healing outcome at 12-month follow-up. Participants of both groups received periapical surgery based on the pre-surgical plan provided by the radiographic imaging methods. Quality of life (QoL) was assessed using Modified Shugars questionnaire. Radiographic analysis for healing was conducted using Molven's criteria and modified PENN 3D criteria. The categorical data between groups were analysed using the Chi-square test, whilst intragroup comparisons were analysed using the McNemar test. The average scores for each component of QoL (oral functions, general functions, pain, swelling and other symptoms), combined QoL scores (overall average of values of 13 variables) and analgesic usage on each day were calculated and analysed.

RESULTS

At 12 months of follow-up, fifty patients were evaluated. Participants in PR group reported significantly more swelling on first three days compared with CBCT group. The analgesic use was higher in the PR group on 2nd and 3rd day (Mann-Whitney U test with Bonferroni correction; p < .007). A significant difference in the limitation of general functions was observed at the second day (p < .07) with the higher values in the PR group. The combined QoL score between the two groups was found to be non-significant. However, none of the patients experienced intraoperative complications or neurovascular exposure. The mean surgical time was lesser in the CBCT group (p < .05). Radiographic healing revealed a success rate of 96.2% for the PR group and 95.8% for the CBCT group with no significant difference between the groups.

CONCLUSION

Participants in the CBCT group experienced substantially less early postoperative swelling and limitation in general functions, in comparison with the PR group. However, preoperative CBCT had no effect on other QoL parameters and intraoperative complications in medium-risk patients. Furthermore, CBCT did not exhibit any added advantage over periapical radiography in terms of assessing healing outcome following endodontic microsurgery. CBCT offered surgically relevant anatomic information for pre-surgical planning and ensured the treatment rendition with a significantly reduced operative time.

Guided Access Cavity Preparation Using a New Simplified Digital Workflow

INTRODUCTION

This study evaluated the precision of a simplified workflow using only preoperative cone-beam computed tomographic (CBCT) scans to gain guided access to root canals of extracted mandibular molars. A workflow using CBCT scanning associated with 3-dimensional oral scanning was used as a reference for comparison. The influence of the presence of coronal restoration in the simplified workflow was also evaluated.

METHODS

Forty-five mandibular molars were randomized into 3 groups: a control group in which digital planning was performed with CBCT and oral scanning and 2 experimental groups in which digital planning was performed only with CBCT examination. In experimental group 1, teeth had no coronal restorations, whereas in group 2 teeth presented with coronal composite restorations. After digital planning, the teeth were accessed using the guides, and a new CBCT scan was made to overlap the pre- and postoperative examinations. Precision was measured by calculating the deviation between the planned and prepared cavities in millimeters and angle. Data were compared using 1-way analysis of variance (P < .05).

RESULTS

All root canals were accessible after access preparation in all tested groups. Deviations of the planned and prepared access cavities were low, with a mean value of 0.55, 0.58, and 0.47 mm and 1.98°, 2.45°, and 1.43° for the control group, group 1, and group 2, respectively. No significant differences in millimeters or angle were observed among the 3 tested groups (P > .05).

CONCLUSIONS

The simplified digital workflow using only CBCT examination allowed a high level of precision in obtaining access in extracted molars with and without coronal restoration, presenting similar results compared with the digital workflow using CBCT and 3-dimensional oral scanning.

Influence of cone beam computed tomography on endodontic treatment planning: A systematic review

OBJECTIVES

The aim of this systematic review was to evaluate how treatment plans changed when cone beam computed tomography (CBCT) imaging was used in endodontic treatment decision-making.

DATA

Studies examining changes in clinicians' treatment plans with and without the use of CBCT were included. Risk of bias assessment was completed using a modification of the Quality Assessment of Diagnostic Accuracy Studies (QUADAS) tool.

SOURCES

A systematic search was performed in PubMed, Embase, Scopus, Cochrane databases from inception to 14 September 2021.

STUDY SELECTION

The initial search identified 3379 titles and abstracts; 20 articles fulfilled inclusion and exclusion criteria for full text review. An additional three articles were identified through citation searching. Sixteen studies met inclusion and exclusion criteria for data extraction and analysis. Fifteen studies reported changes in treatment plan with CBCT imaging. Five studies reported changes in 45 - 66.7% of the cases but did not mention specific treatment options. Of the 11 remaining studies, 10 studies reported changes in 24.3 - 56% of cases and changes in treatment options, while one study reported no significant change in treatment plan after CBCT imaging was introduced. With CBCT imaging, clinicians were more likely to prescribe further intervention that included endodontic treatment and extractions.

CONCLUSION

Although the current evidence was heterogeneous, it was clear that CBCT offered more information than periapical radiography. This influenced endodontic treatment decision-making and in more complex cases, led to further intervention including non-surgical and surgical endodontic treatment and extractions.

CLINICAL SIGNIFICANCE

Additional information from CBCT imaging influenced endodontic treatment decision-making in the following situations: high difficulty cases, diagnosis of symptomatic teeth after failed root canal treatment, evaluation of periapical healing, pre-surgical treatment planning, and management of traumatised immature teeth and external cervical resorption.

Endodontic treatment of the mandibular first molar with six root canals: A case report and literature review

The mandibular first molars normally have three or four root canals and rarely have five or more root canals. The present study reported a rare anatomical configuration with six root canals in the mandibular right first molar diagnosed during endodontic treatment using a dental operating microscope and confirmed with the help of cone-beam computed tomography (CBCT) images. The present case report revealed that there is an increasing possibility of detecting additional canals through the magnification of the microscope and the improvement of CBCT diagnostic technology. As more abnormal morphologies in root canals are reported, dentists need to understand this diversity in anatomical structure and improve treatment techniques.

Present status and future directions: Root resorption

Root resorption is the loss of dental hard tissue because of odontoclastic action. In permanent teeth, it is undesirable and pathological in nature. Root resorption may occur on the inner aspect of the root canal (internal root resorption) or on the outer aspect of the root (external root resorption). Regardless of its location, root resorption is irreversible, and may result in discomfort for the patient, requires management and/or, in some cases, results in the premature loss of the affected tooth. Root resorption is often challenging to accurately diagnose and manage. The aim of this narrative review is to present the relevant literature on the aetiology, pathogenesis, diagnosis and management, as well as discuss the future directions of diagnosis and management of root resorption.

Endodontic working length measurements of premolars and molars in high-resolution dental MRI: a clinical pilot study for assessment of reliability and accuracy

OBJECTIVES

To prospectively assess the reliability and accuracy of high-resolution, dental MRI (dMRI) for endodontic working length (WL) measurements of premolars and molars under clinical conditions.

MATERIALS AND METHODS

Three-Tesla dMRI was performed in 9 subjects who also had undergone cone-beam computed tomography (CBCT) (mean age: 47 ± 13.5 years). A total of 34 root canals from 12 molars (4/8, upper/lower jaw; 22 root canals) and 11 premolars (2/9 upper/lower jaw; 12 root canals) were included. CBCT and dMRI datasets were reconstructed to visualize the root canal in one single slice. Subsequently, two radiologists measured the root canal lengths in both modalities twice in blinded fashion. Reliability and accuracy for both modalities were assessed using intraclass correlation coefficients (ICCs) and Bland-Altman analysis, respectively.

RESULTS

Reliability (intra-rater I/II; inter-rater) of dental MRI measurements was excellent and comparable to CBCT for premolars (0.993/0.900; 0.958 vs. 0.993/0.956; 0.951) and for molars (0.978/0.995; 0.986 vs. 0.992/0.996; 0.989). Bland-Altman analysis revealed a mean underestimation/bias (95% confidence interval) of dMRI measurements of 0.8 (- 1.44/3.05) mm for premolars and 0.4 (- 1.55/2.39) mm for molars. In up to 59% of the cases, the accuracy of dMRI for WL measurements was within the underestimation margin of 0 to 2 mm short of the apical foramen AF.

CONCLUSIONS

In vivo demonstration and measurement of WL are feasible using dMRI. The reliability of measurements is high and equivalent to CBCT. Nonetheless, due to lower spatial resolution and longer acquisition time, the accuracy of dMRI is inferior to CBCT, impeding its current use for clinical treatment planning.

CLINICAL RELEVANCE

dMRI is a promising radiation-free imaging technique. Its reliability for endodontic working length measurements is high, but its accuracy is not satisfactory enough yet.

3D geometric analysis of second mesiobuccal canal in permanent maxillary first molar tooth

Cone-beam computed tomography scans exhibiting a second mesiobuccal (MB2) canal were examined. The vertical distance of the MB2 orifice from the pulp floor (depth), inter-orifice distance (IOD) of MB2 from mesiobuccal (MB) and palatal (P) orifices, the horizontal distance of the MB2 orifice from the line joining MB-P orifices [mesial deviation (MD)] and root canal configuration (RCC) were evaluated on 330 scans. The Student's t-test, ANOVA, Spearman's correlation and linear regression analysis were applied. The MB2 depth was 1.69 ± 0.86 mm. IOD (MB-MB2, MB2-P) was 2.18 ± 0.58 mm and 4.63 ± 1.06 mm, respectively. MD was 1.02 ± 0.37 mm. The predominant RCC was Vertucci's type II (75.5%). No correlation of depth with IOD of MB-MB2 (rho = 0.0367, p = 0.506) was observed. Significant correlation of depth with IOD of MB2-P (rho = 0.696, p < 0.001) and MD (rho = 0.174, p = 0.001) was established. No association of depth with age and IOD (MB-MB2) was observed on linear regression analysis. However, a significant positive association was established with IOD (MB2-P) (p < 0.001) and MD (p = 0.001).

The Effect of Cone-Beam Computed Tomography (CBCT) Evaluation on Treatment Planning after Endodontic Instrument Fracture

Intracanal instrument fracture is a procedural iatrogenic event during endodontic treatment that may affect treatment planning and eventually treatment outcome. Cone Beam Computed Tomography (CBCT) has offered several advantages, especially in endodontic cases in which information from conventional periapical radiograph may not be adequate to allow a precise treatment planning decision and a subsequent appropriate management of the cases. The present study was firstly conducted to assess the effect of CBCT evaluation on the decision-making process after instrument fracture; secondly, to introduce a new clinical approach in cases with fractured instruments located in the mesial roots of mandibular and maxillary molars. The study design was observational. The sample comprised all cases of mandibular and maxillary molars where an instrument fracture had occurred in the mesial roots. Two qualified (National and Kapodistrian University of Athens, Greece) and experienced (more than fifteen years of daily practicing) endodontists evaluated all the cases. The initial treatment plan made by evaluating periapical radiographs of each case was compared to the final plan set after CBCT evaluation. A marginal homogeneity test for paired data was conducted to test the concordance of treatment planning with periapical radiographs versus CBCT. Multivariable logistic regression was structured to identify predictors of modification in treatment planning following CBCT assessment, and to record estimators for decision to remove, bypass or retain the fragment. The level of statistical significance was pre-specified at p < 0.05. Of a total 52 cases evaluated, change in treatment planning with conventional periapical radiograph as a reference, following evaluation of CBCT, was observed in more than half of the teeth. The difference was statistically significant (p < 0.001). Apical location of the fragment was more likely to induce a perceived change in treatment planning after CBCT evaluation (p < 0.01). Canal merging induced 95% lower odds (p = 0.01) for taking a decision to remove or bypass, revealing that retaining the fragment was by far a more likely decision. A significant impact of CBCT preoperative evaluation on treatment planning for the management of such cases was demonstrated. Apical location of the fragment and canal merging seem to influence the decision-making process.

Vertical root fractures in root treated teeth-current status and future trends

Vertical root fracture (VRF) is a common reason for the extraction of root filled teeth. The accurate diagnosis of VRF may be challenging due to the absence of clinical signs, whilst conventional radiographic assessment is often inconclusive. However, an understanding of the aetiology of VRFs, and more importantly, the key predisposing factors, is crucial in identifying teeth that may be susceptible. Thorough clinical examination with magnification and co-axial lighting is essential in identifying VRFs, and although CBCT is unable to reliably detect VRFs per se, the pattern of bone loss typically associated with VRF can be fully appreciated, and therefore, increases the probability of correct diagnosis and management. The prevalence of VRFs in root filled teeth is significantly greater than in teeth with vital pulps, demonstrating that the combination of loss of structural integrity, presence of pre-existing fractures and biochemical effects of loss of vitality, are highly relevant. Careful assessment of the occlusal scheme, presence of deflective contacts and identification of parafunctional habits is imperative in both preventing and managing VRFs. Furthermore, anatomical factors such as root canal morphology, may predispose certain teeth to VRF. The influence of access cavity design and root canal instrumentation protocols should be considered although the impact of these on the fracture resistance of root filled teeth is not clearly validated. The post-endodontic restoration of root filled teeth should be expedient and considerate to the residual tooth structure. Posts should be placed 'passively' and excessive 'post-space' preparation should be avoided. This narrative review aims to present the aetiology, potential predisposing factors, histopathology, diagnosis and management of VRF and present perspectives for future research. Currently, there are limited options other than extraction for the management of VRF, although root resection may be considered in multi-rooted teeth. Innovative techniques to 'repair' VRFs using both orthograde and surgical approaches require further research and validation. The prevention of VRFs is critical; identifying susceptible teeth, utilizing conservative endodontic procedures, together with expedient and appropriate post-endodontic restorative procedures is paramount to reducing the incidence of terminal VRFs.

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.

Cone-beam computed tomography evaluation of C-shaped root and canal morphology of mandibular premolars

BACKGROUND

Mandibular premolars are complicated teeth to endodontically treat due to the anatomical variations that can present. The purpose of this study was to determine the presence of C-shaped configurations in mandibular premolars by cone-beam computed tomography (CBCT).

METHODS

380 mandibular first premolars and 308 mandibular second premolars cone-beam computed tomographic images were obtained from 292 patients (175 female and 117 male). Tooth position, number of roots, root canals, C-shaped root canal system configuration, level of canal bifurcation and radicular grooves were evaluated by two endodontists trained in CBCT evaluation; previously calibrated between them, and a radiologist with endodontic experience. Data were statistically compared by The Chi-square test (α = 0.05) to examine any significant difference between gender and C-shaped root canal system and any significant difference between C-shaped configuration according to Fan criteria and gender.

RESULTS

Overall 100% (n = 688) teeth examined, 19.2% (n = 132) had a C-shaped root canals system. 9.16% (n = 63) in male patients and 10.03% (n = 69) in female patients. The prevalence of C-shaped root canal system in mandibular first premolar was 83.33 and 16.66% in mandibular second premolars. According to Fan classification, the mandibular first premolars showed 3.63% as C1, 9.09% C2, 59.09% C3, 21.81% C4a, 1.8% C4b. Mandibular second premolars showed 13.63% as C1, 18.18% C2, 13.63% C3, 27.27% C4a, 9.09% C4b. Male patients showed 4.54% as C1, 3.78% C2, 22.72% C3, 11.36% C4a, 0.75% C4b, and 4.54% out of classification. Female patients showed 0.75% as C1, 6.81% C2, 30.03% C3, 9.84 C4a, 2.27% C4b, and 2.27% out of classification. The 53.36% canal bifurcation in mandibular first premolars and 50.09% in mandibular second premolars were in the middle third. No statistical differences were found between C-shaped root canal system and gender or C-shaped configuration according to Fan criteria and gender. P was < 0.05.

CONCLUSIONS

Within the limitation of this study, the presence of C-shaped anatomical system is relatively low in mandibular second premolars than in mandibular first premolars.

An Update of the Possible Applications of Magnetic Resonance Imaging (MRI) in Dentistry: A Literature Review

This narrative review aims to evaluate the current evidence for the application of magnetic resonance imaging (MRI), a radiation-free diagnostic exam, in some fields of dentistry.

BACKGROUND

Radiographic imaging plays a significant role in current first and second level dental diagnostics and treatment planning. However, the main disadvantage is the high exposure to ionizing radiation for patients.

METHODS

A search for articles on dental MRI was performed using the PubMed electronic database, and 37 studies were included. Only some articles about endodontics, conservative dentistry, implantology, and oral and craniofacial surgery that best represented the aim of this study were selected.

RESULTS

All the included articles showed that MRI can obtain well-defined images, which can be applied in operative dentistry.

CONCLUSIONS

This review highlights the potential of MRI for diagnosis in dental clinical practice, without the risk of biological damage from continuous ionizing radiation exposure.

[Imaginology in the diagnosis and planning of root duct systems: an updated review]

Root canal systems present a varied morphological conformation for each group of teeth. Several authors have described the anatomical conformation and its variants in different classifications, including the main, collateral, lateral, secondary, accessory, interduct, recurrent, apical delta and interradicular cavus canals. Currently, radiology still does not allow visualization of all these structures. However, proper use of imaging techniques together with the use of new 3D equipment for adjustments of acquisition parameters with adequate software and algorithms allows greater image precision, facilitating diagnosis and the planning of the most adequate approach for endodontic treatments. The objective of this article was to conduct a review of the literature to identify new concepts and useful imaging tools for better diagnoses.

Endodontic management of mandibular second molar fused to odontome with 12-month follow-up using cone beam computed tomography: A case report

Fusion is a developmental anomaly characterised by the union of two adjacent teeth or tooth-like substance. Odontomes are malformation of the dental tissue which arise during normal tooth development. They are usually asymptomatic but often associated with tooth eruption disturbance. In this paper, we report a rare case of fusion involving permanent mandibular second molar with an odontome, which led to a partial eruption of the molar as well as its devitalisation. Successful endodontic management was carried out in this case with a supplementary disinfection procedure using XP Endo finisher (FKG Dentaire, La Chaux-de-Fonds, Switzerland). The use of high-end diagnostic imaging modalities such as cone beam computed tomography (CBCT) helped in making a confirmatory diagnosis; determining the treatment plan before undertaking the actual treatment; for better understanding of the fused tooth's complicated root morphology; and for its effective management and to follow up this unusual case for 12 months.

Clinical endodontic management during the COVID-19 pandemic: a literature review and clinical recommendations

The spread of the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has resulted in millions of confirmed cases and hundreds of thousands of deaths. Despite all efforts to contain the spread of the disease, the number of infections and deaths continue to rise, particularly in some regions. Given its presence in the salivary secretions of affected patients, and the presence of many reported asymptomatic cases that have tested positive for COVID-19, dental professionals, including Endodontists, are at high risk of becoming infected if they do not take appropriate precautions. As of today, there are no predictable treatments or approved vaccines that can protect the public and healthcare professionals from the virus; however, there is speculation that a vaccine might be available sometime in 2021. Until then, general dentists and Endodontist will need to be able to treat emergency patients in order to relieve pressure on emergency clinics in hospitals or local community hubs. In addition, as the pandemic continues, strategies to manage patients will need to evolve from a palliative to a more permanent/definitive treatment approach. In this article, an update on the treatment considerations for dental care in general is provided, as well as a discussion on the available endodontic guidelines reported in the literature. Recommendations on clinical management of endodontic emergencies are proposed.

Guided Endodontic Treatment of Calcified Lower Incisors: A Case Report

A 52-year-old female patient was diagnosed with chronic periapical periodontitis associated with severely calcified lower central incisors. Radiographic examination revealed no visible root canal in the coronal-third of the root. After choosing the guided endodontic treatment, an intraoral scan (Trios, 3shape, Copenhagen, Denmark), in conjunction with a cone beam computed tomography (CBCT) scan, was taken in order to design and fabricate a printed guide. Virtual implant software was used to visualize the surgical access into the sclerosed root canals. After locating the canals, the guide was removed, and the teeth were treated under a rubber dam. The guided approach allows predictable, efficient endodontic treatment of teeth presenting calcified canals, with minimal removal of sound dentine and less risk of root perforations.