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Aim: To evaluate the indication of the endodontic treatment for vital intact teeth with the root apex involved in large radicular cystic lesions of endodontic origin. Methodology: This prospective cohort study enrolled healthy participants with radicular cysts of endodontic origin and with the root apex of vital intact teeth involved in the bone defect, as determined by cone beam computed tomography (CBCT). Thirty‐two sound vital teeth were analysed by thermal (TPT) and electric pulp tests (EPT) before surgery (T0) and 1 week (T1), 2 weeks (T2), 3 months (T3) and 6 months (T4) post‐surgery. Student's t‐test (p <.05) was used to compare the EPT values at baseline and T4. anova (p <.05) was used to analyse the EPT variations for all maxillary and mandibular teeth. McNemar test (p <.05) was used to compare the results according to variation in EPT values gathering by variation, no variation and no response. Results: At T1, 75 and 65.7% of teeth responded positively whilst 25 and 34.3% did not respond to EPT and TPT, respectively. The variation of the EPT values between T0 and T1 was observed for 50.0% of teeth, whilst no variation was noticed in 25.0% of teeth. At T4, 90.6 and 87.5% of teeth responded positively whilst 9.4 and 12.5% did not respond to EPT and TPT, respectively. At T4, variation of the EPT values between T0 and T4 was observed for 28.1%, whilst no variation was noticed in 62.5% of teeth. There were no statistical differences in EPT results between T0 and T4 (p >.05), but significant differences were observed for EPT values between T1 and T4 (p <.05), and between mandibular and maxillary teeth. The pulp sensibility of maxillary teeth worsened after surgery, before reverting progressively to T0 values, whilst no statistically significant differences were observed for mandibular teeth at the different time points. Conclusions: These data support the inconsistence of the prophylactic endodontic treatment in healthy vital teeth with apex involvement in large cystic lesions of endodontic origin. Post‐surgery follow‐up with TPT and EPT is recommended to assess pulp status. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]

Aim: Several factors influence the condition of the periapical tissues associated with root filled teeth. The primary objective of this study was to retrospectively evaluate the extent and speed of bone healing of large periapical lesions associated with nonsurgical root canal treatment or retreatment. The secondary objective was to analyse the relationship between the time to complete healing when analysed using cone beam computed tomography (CBCT) and other possible predictors that affect healing. Methodology: Seventy‐nine patients were treated during the years 2013–2020 with large periapical lesions of endodontic origin (10–15 mm) as observed on intraoral periapical radiographs (IOPAR) were included. IOPAR and CBCT were available before treatment and during the follow‐up (IOPAR every 6 months and CBCT every 12 months). The volume of periapical lesions was calculated by OsiriX Lite software. Variables such as initial volume of the lesion, age, gender, type of treatment or type of root canal filling were compared to identify the differences between healed and unhealed lesions. Pearson's Chi‐square test was used for categorical variables, the t‐test for age and the Wilcoxon test for initial volume of the lesion. The association between time to healing and the variables was assessed using univariate analysis and multivariate analysis. The Wilcoxon test was used to observe the association of healing time with categorical variables and the correlation index was measured with the quantitative variables. Results: Of the 79 cases analysed, 60 lesions (76%) were completely healed as verified by CBCT in a mean healing time of 19 months, of which 60% healed fully between 12 and 18 months. Increase in age of patient and larger initial volume of the lesion were associated with a significantly longer healing time (p <.001). Gender, filling material and type of treatment did not have a significant effect on the healing process (p >.05). Conclusions: Clinicians should be aware that periapical lesions in older patients and larger areas of bone loss take longer to heal. CBCT monitoring of large periapical lesions is critical and it can help clinicians in the decision‐making process. [ABSTRACT FROM AUTHOR]

Aim: To investigate current endodontic practices, adoption of technologies and continuing education attendance within specialist endodontic practice globally and to identify geographic trends. Methodology: A web‐based survey of endodontic association members in Australia, Britain, Canada, Italy, New Zealand and the USA on routine treatment preferences, armamentarium and education attendance was conducted. Chi‐squared, independent sample t‐tests, Cochran's Q test and McNemar's test were performed. Results: The survey was completed by 543 endodontists or endodontic post‐graduate students. Almost all respondents used the dental operating microscope (DOM, 91.3%), engine‐driven nickel–titanium instruments (NiTi, 97.6%), electronic apex locators (EAL, 93.0%), cone‐beam computed tomography (CBCT, 91.2%) and calcium silicate‐based materials (CSBMs, 93.7%). Dental dam was always used by 99.1%. Over half used irrigation adjuncts (81.8%), warm vertical compaction (74.6%) and heat‐treated NiTi (60.2%). Geographic comparison between AP (Asia–Pacific, n = 78), AM (Americas, n = 402) and EM (Europe and Middle East, n = 63) was performed. AM and EM preferred single‐visit treatment more (p <.001) and used higher sodium hypochlorite concentrations than AP. AM had more access to CBCT in the workplace (86.6%) than AP (65.4%, p <.001) and used CBCT for routine preoperative assessment (39.6%) more than EM (7.3%, p <.001). Almost all of EM used irrigation adjuncts (95.2%), more than AM (78.1%, p =.001). AP used steroid/antibiotic medicaments most (p <.001) and had the highest attendance at continuing education programmes. Conclusion: Several endodontic‐specific armamentaria have reached almost complete adoption within global specialist endodontic practice, whilst the continued uptake of newer technologies should be followed over time. Some practising philosophies varied significantly across different geographic regions. [ABSTRACT FROM AUTHOR]

Aim: To evaluate two‐ and three‐dimensionally the effect of resorbable collagen‐based bone‐filling material on periapical healing of endodontic lesions with four‐wall defects following endodontic microsurgery (EMS). Methodology: This parallel, randomized controlled superiority clinical trial involved 86 lesions with the strictly endodontic origin and four‐wall defect morphology. EMS procedures were performed by calibrated postgraduate residents. Before flap closure, osteotomies were randomized to the control or treatment group. In the control group, the flap was repositioned with no material added. In the treatment group, a collagen‐based bone‐filling augmentation material was placed into the osteotomy. Clinical and radiographic examinations were completed after 12 months. Periapical healing was evaluated by blinded evaluators using periapical (PA) radiographs according to Molven's criteria and cone beam computed tomography (CBCT) scans according to PENN's 3D criteria. Cortical plate healing was scored according to the RAC/B index. The data were analysed using Fisher's exact test, Logistic regression models and Chi‐squared test. The significance level was predetermined at p <.05. Results: Sixty‐six cases were evaluated at the 12‐month follow‐up, with 30 and 36 cases in the control and treatment groups, respectively. Only the asymptomatic cases (control = 26, treatment = 32) were included in the radiographic evaluation. Twenty‐three cases (88.5%) in the control and 28 (87.5%) cases in the treatment group demonstrated complete healing on PA radiographs (p = 1.000). On CBCT, 10 (38.4%) and 21 (65.6%) cases had completely healed in the control and treatment groups, respectively (p =.095). The re‐establishment of the buccal cortical plate was detected in 12 (46.2%) and 22 (68.8%) cases in the control and treatment groups, respectively (p =.243). Conclusion: Within the limitations of the present study, the use of collagen‐based bone‐filling material had no statistically significant effect on the periapical healing of endodontic lesions with four‐wall defect following EMS at the 12‐month follow‐up when evaluated by PA radiographs or CBCT scans. However, the observed higher percentage of a re‐established cortical plate in the treatment group could suggest a clinical benefit that is of interest after surgical endodontic treatment. [ABSTRACT FROM AUTHOR]

Aim: To determine the prevalence of symptoms, clinical signs and radiographic presentation of external cervical resorption (ECR). Methodology: This study involved 215 ECR lesions in 194 patients referred to the Endodontic postgraduate Unit at King's College London or Specialist Endodontic practice (London, UK). The clinical and radiographic findings (periapical [PA] and cone beam computed tomography [CBCT]) were readily accessible for evaluation. A checklist was used for data collection. Inferential analysis was carried out to determine if there was any potential association between type and location of tooth in the jaw as well as sex, age of the patient and ECR presentation and radiographic feature. Results: Eighty‐eight patients (94 teeth) were female and 106 patients were male (121 teeth), the mean age (±SD) was 41.5 (±17.7) years. Fifteen patients (7.7%) had more than one ECR lesion. The most affected teeth were maxillary central incisors (21.4% [46 teeth]) and mandibular first molars (10.2% [22 teeth]). ECR was most commonly detected as an incidental radiographic finding in 58.1% [125 teeth] of the cases. ECR presented with symptoms of pulpal/periapical disease in 23.3% [n = 50] and clinical signs (e.g. pink spot, cavitation) in 16.7% [36 teeth] of the cases. Clinical signs such as cavitation (14%), pink spot (5.1%) and discolouration (2.8%) were uncommon, but their incidence increased up to 24.7% when combined with other clinical findings. ECR was detected in the resorptive and reparative phases in 70.2% and 29.8% of the cases respectively. Conclusion: ECR appears to be quiescent in nature, the majority being asymptomatic and diagnosed incidentally from PA or CBCT. When assessed with the Patel classification, most lesions were minimal to moderate in relation to their height (1 or 2) and circumferential spread (A or B). However, the majority of ECRs were in (close) proximity to the pulp. Symptoms and clinical signs were associated with (probable) pulp involvement rather than the height and circumferential spread of the lesion. Clinical signs were more frequently associated when ECR affected multiple surfaces. [ABSTRACT FROM AUTHOR]

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). [ABSTRACT FROM AUTHOR]

Aim: To determine the efficacy of a combination of injectable‐platelet‐rich fibrin and type‐1 collagen particles on the healing of through‐and‐through periapical bone defect and subsequent closure of bony window. Methodology: The clinical trial was registered in ClinicalTrials.gov (NCT04391725). Thirty‐eight individuals with radiographic evidence of periapical radiolucency in maxillary anterior teeth and confirmed loss of palatal cortical plates in cone beam computed tomographic imaging were randomly assigned to either the experimental group (n = 19) or the control group (n = 19). A mixture of i‐PRF and collagen as a graft was applied to the defect in adjunct to periapical surgery in the experimental group. No guided bone regeneration procedures were used in the control group. The healing was evaluated using Molven's (2D) and modified PENN 3D (3D) criteria. Percentage reduction of the buccal and palatal bony window area, and complete closure of through‐and‐through periapical bony window (tunnel defect) were assessed using Radiant Diacom viewer software (Version 4.0.2). The reduction in the periapical lesion area and volume was measured using Corel DRAW and ITK Snap software. Results: Thirty‐four participants (18 and 16 in the experimental and control groups respectively) reported for follow‐up at 12 months. There was 96.9% and 97.96% reduction of buccal bony window area in the experimental and control groups respectively. Similarly, palatal window showed 99.03% and 100% reduction in the experimental and control groups respectively. No significant difference in both buccal and palatal window reduction was noticed between the groups. A total of 14 cases (seven in the experimental group and seven in the control group) showed complete closure of through‐and‐through bony window. No significant difference in clinical, 2D and 3D radiographic healing, percentage reduction in area and volume was observed between the experimental and control groups (p >.05). Neither the area nor the volume of lesion, and the size of buccal or palatal window had significant effect on healing of through‐and‐through defects. Conclusion: Endodontic microsurgery results in high success rate in large periapical lesions with through‐and‐through communication with more than 80% reduction in volume of lesion and size of both buccal and palatal window after 1 year. A mixture of type‐1 collagen particles and i‐PRF, adjunct to periapical micro‐surgery did not improve the healing in through‐and‐through periapical defects. [ABSTRACT FROM AUTHOR]

These may be related to a "structure" (such as anatomy), a "disease" (such as pulp and periapical diseases), a "material" (such as bioceramic materials) or a "procedure" (such as diagnostic and root canal treatment procedures). Consensus, controversial terms, endodontics, root canal treatment, glossary 5 Ahmed, H.M.A., Versiani, M.A., De-Deus, G. & Dummer, P.M.H. (2017) A new system for classifying root and root canal morphology. Keywords: consensus; controversial terms; endodontics; glossary; root canal treatment EN consensus controversial terms endodontics glossary root canal treatment 788 791 4 06/13/23 20230701 NES 230701 INTRODUCTION Scientific terminology is an essential tool of communication as it plays a critical role in the understanding of scientific and technical terms and their associated definitions (Sageder, [34]). [Extracted from the article]

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. [ABSTRACT FROM AUTHOR]

Aim: The aim of this cone‐beam computed tomography (CBCT)‐based study was to evaluate the outcome of nonsurgical root canal treatment (RCT) performed for the management of large cyst‐like periapical lesions (LCPL) and to identify the predictive factors affecting healing. Methodology: Fifty‐four subjects (77 permanent maxillary anterior teeth) with LCPL (>10 mm) of endodontic origin were included. A single operator performed standardized multi‐visit RCT. Patients were clinically and radiographically examined at 6, 12 months, and a CBCT scan was taken at 24 months. Two independent blinded evaluators measured the pre‐ and postoperative volume of periapical lesions on CBCT scans using ITK snap software (version 3.8.0‐beta‐20181028‐win64). The outcome was assessed as a percentage change in lesion volume and dichotomized as success (resolved/reduced) or failure (unchanged/enlarged). Ten preoperative (gender; age; intraoral draining sinus, soft tissue swelling, tooth discoloration, pulp canal obliteration, open apex, root resorption, cortical bone defect and lesion volume) and four intraoperative (apical extent and density of root filling; number of treatment visits and type of root filling) predictive factors were observed. Bivariate and stepwise multivariable linear regression analysis was performed to identify independent predictors affecting treatment outcomes. The significance level was set at 5%. Results: A recall rate of 88% was achieved. The success rate of RCT was 82.2% (8.9% resolved, 73.3% reduced). Median lesion volume reduction was 75% (IQR 61%–93%). No pre‐ or intra‐operative factors were related to treatment failure. However, presence of preoperative cortical bone defect (palatal versus no cortical defect, β = −51.5; 95% CI: −86.9 to −16, p =.006) and apical extent of obturation (long versus flush, β = −27.2; 95% CI: −53.8 to −0.6, p =.04) were negatively associated with reduction in lesion volume (%). Conclusion: Large cyst‐like periapical lesions may be successfully managed with RCT. Preoperative cortical bone defect and apical extent of obturation may negatively influence osseous healing. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]

Aim: To describe a novel surgical method (crown rotation surgery) to manage inversely impacted central incisors with immature roots. Methodology: Two young patients each presented with an inversely impacted maxillary central incisor. To protect the apical tissues, the two impacted incisors were rotated downwards to a relatively normal position without extraction from their bony sockets. Results: After crown rotation surgery, spontaneous eruption, continuous root development, and periodontal healing of the rotated incisors were observed. The pulp retained vitality and blood flow was normal. Moreover, there were no obvious signs of pulp canal obliteration (PCO), as indicated by Cone Beam Computed Tomography (CBCT) imaging. Conclusions: By optimising protection of the vital pulp and apical tissues, crown rotation surgery represents a minimally invasive, conservative, and practical surgical technique for treating inversely impacted incisors with developing roots. In contrast to existing surgical methods, crown rotation surgery may avoid certain complications, including PCO and abnormal or arrested root development. Key learning points: By optimizing protection of the vital pulp and apical tissues, crown rotation surgery represents a minimally invasive, conservative and practical surgical technique for treating inversely impacted incisors with developing roots.In contrast to existing surgical methods, crown rotation surgery may avoid certain complications, including PCO and abnormal or arrested root development. [ABSTRACT FROM AUTHOR]

The technical execution of root canal treatment procedures demands a thorough understanding and knowledge of root and canal anatomy. Over the decades, and with the aid of various research methods such as staining and clearing, 2D radiographic imaging, sectioning procedures, cone beam computed tomography and micro‐computed tomography, many laboratory and clinical studies have been undertaken to understand the root and canal anatomy of the human dentition. This has resulted in a tremendous increase in the body of knowledge with a wide range of qualitative and quantitative presentations of the root and canal anatomy. This review aims to provide a critical analysis for the laboratory and clinical research methods in root and canal anatomy studies. In addition, it aims to identify existing gaps and present insights for directions of future research and ways for translation to clinical endodontics. [ABSTRACT FROM AUTHOR]

The technical execution of root canal treatment procedures demands a thorough understanding and knowledge of root and canal anatomy. Over the decades, and with the aid of various research methods such as staining and clearing, 2D radiographic imaging, sectioning procedures, cone beam computed tomography and micro‐computed tomography, many laboratory and clinical studies have been undertaken to understand the root and canal anatomy of the human dentition. This has resulted in a tremendous increase in the body of knowledge with a wide range of qualitative and quantitative presentations of the root and canal anatomy. This review aims to provide a critical analysis for the laboratory and clinical research methods in root and canal anatomy studies. In addition, it aims to identify existing gaps and present insights for directions of future research and ways for translation to clinical endodontics. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]

Aim: To evaluate the effect of an enhanced infection control protocol on root canal treatment outcomes and on microbial load within root canals after chemomechanical preparation. Methodology: A total of 144 molar teeth from 139 healthy patients receiving primary root canal treatment were block randomized to a standard protocol (StP) or an enhanced infection control protocol (EnP). Both treatment arms adhered to current best practice recommendations, while the EnP comprised additional steps that included replacing rubber dams, gloves, files, all instruments and surface barriers at the time of canal filling to reduce the chances of iatrogenic contamination. Patients and radiographic examiners were blinded to the protocol used. Intracanal microbial samples were taken at baseline (S1) and after completion of chemomechanical preparation (S2). Microbial 16S rDNA copy numbers were enumerated by quantitative polymerase chain reaction (qPCR). Cone beam computed tomography (CBCT) scans were taken before treatment and at one‐year follow‐up. The outcome was assessed clinically and radiographically using CBCT by logistic regression modelling. Results: At one‐year follow‐up, 115 teeth were analysed (54 in StP and 61 in EnP). The percentage of favourable outcomes assessed by CBCT was 85.2% in the EnP and 66.7% in the StP. The odds of 12‐month success was three times higher in the EnP group compared with the StP group (OR=2.89; p=0.022, CI: 1.17 – 7.15). The median bacterial reads were reduced from 8.1×103 in S1 samples to 3.5×103 in the StP group and from 8.6×103 to 1.3×103 in the EnP group. The enhanced protocol significantly reduced bacterial counts in pre‐canal filling samples when compared to the standard protocol (p=0.009). Conclusions: The implementation of a facile, enhanced infection control protocol in primary root canal treatment resulted in less detectable bacterial DNA before canal filling and significantly more successful outcomes at one year. [ABSTRACT FROM AUTHOR]

Background: The effectiveness of the metal artefact reduction (MAR) tool for the detection of vertical root fracture (VRF) by cone beam computed tomography (CBCT) images is controversial. Objective: To evaluate the effectiveness of the MAR tool on VRF detection involving teeth with intracanal materials in CBCT images. Methodology: In September 2019, an electronic search was performed in six databases (PubMed, Scopus, Web of Science, Cochrane, Lilacs and Embase). The electronic search was updated in May 2020 through searches in Google Scholar and references of included studies (embracing the electronic and gray literature searches). No language or year restrictions were applied. Independently, two reviewers examined titles, abstracts and full texts according to the eligibility criteria that were as follows: diagnostic studies that evaluated the effectiveness of the MAR tool on the diagnosis of VRF in human teeth (laboratory or in vivo studies) on CBCT images. The risk of bias was evaluated using the Quality Assessment Tool for Diagnostic of Accuracy Studies‐2 (QUADAS‐2). For conducting the meta‐analysis, the values of sensitivity, specificity, diagnostic odds ratio (DOR) and area under the ROC curve (AUC) were obtained, considering the subgroups with and without MAR active. The Grading of Recommendation, Assessment, Development and Evaluation instrument was applied to assess the level of evidence across the studies using GRADEpro software. Results: A total of 8 laboratory studies were included in both systematic review and meta‐analysis. The values of sensitivity, specificity, DOR and AUC to VRF diagnosis with and without MAR active were, respectively, 0.586 and 0.603; 0.699 and 0.713, 3.037 and 3.767; 0.67 and 0.71. The quality of the evidence suggested low confidence in estimating the outcomes. Discussion: The MAR tool decreased slightly the diagnostic values of VRF involving teeth with intracanal materials in laboratory studies. However, it is important to highlight that most studies had an uncertain risk of bias. Conclusions: Although a low level of evidence and high heterogeneity were observed in the included studies, the meta‐analysis revealed better diagnosis values for VRF detection when the MAR was deactivated when analysing extracted teeth in a laboratory setting. Registration: PROSPERO—CRD42020145222. Funding: This study was financed in party by the Coordenação de Aperfeiçoamento de Pessoal de Nível Superior—Brasil (CAPES). [ABSTRACT FROM AUTHOR]

Aim: To evaluate 3D accuracy and outcome of a dynamic navigation method for guided root canal treatment of severe pulp canal obliteration (PCO) in 3D printed jaws. Methodology: Three operators with different levels of experience in Endodontics performed navigated access cavities, using the Navident system (ClaroNav), in two sets (maxillary and mandibular) of 3D‐printed jaw models with teeth presenting severe PCO. Models were mounted on a phantom to mimic a real clinical situation. After treatment, a postoperative high resolution Cone‐Beam Computer Tomography (CBCT) scan (NewTom) was taken for each model and registered to the preoperative model. All access cavities were then segmented using 3‐Matic Medical software 15.0 (Materialise). Length and volume of each access cavity were measured, and a comparison was done by measuring the distance deviation in mm at the coronal entry point, apical point, vertical deviation, total deviation and angular deviation of the access cavity in comparison with the virtual planning. Additionally, all access cavities were scouted with a size 10 K‐file and inspected on the CBCT to confirm that the canal was located. Descriptive statistics for each parameter were performed. Normality of the data was assessed; data were transformed if needed to make it normally distributed. One‐way analysis of variance (anova) was applied to assess differences between parameters for tooth type, jaw, and operators and corrected for simultaneous hypothesis testing according to Tukey. Significance level was set at.05. Results: After training with the system (28 cavities per operator), a total of 132 teeth and 168 access cavities (56 per operator) were prepared. All operators located a total of 156 canals, obtaining an overall success of 93% without a difference between operator experience (p >.05). The mean deviation at the apical point was 0.63 mm (SD 0.35) and was significantly lower in anterior teeth in comparison with molars (p <.05). The mean angular deviation from the planning was 2.81° (SD 1.53). Conclusion: Dynamic navigation was an accurate approach for root canal treatment in teeth with severely calcified canals. However, the technique has a learning curve and requires extensive training prior to its use clinically. [ABSTRACT FROM AUTHOR]

Aim: To compare the diagnostic accuracy of periapical radiography (PR) and cone‐beam computed tomography (CBCT) for detecting pathoses of endodontic origin using the gold standard of direct surgical visualization. Methodology: Seventy‐four patients (112 teeth) underwent radiographic examination by periapical radiography and CBCT. The presence of periapical lesions, root perforations and their locations, root fractures, different types of external root resorptive defects, apicomarginal bone defects, through and through bone defects, buccal bone status and proximity of root apices and lesions to vital anatomical structures were assessed. These same parameters were assessed intraoperatively by direct surgical visualization which served as the gold standard reference for the radiographic assessments. Sensitivity, specificity, positive predictive values, negative predictive values were determined for comparison of diagnostic accuracy between two modalities. Results: There were no significant differences between the two imaging modalities for root resorptive defects and root fractures. However, CBCT accurately detected periapical lesions, root perforations, apicomarginal bone defects and through and through bone defects. The overall accuracy of CBCT varied from 91% to 96% in detecting dehiscence and fenestration of buccal cortical plates. Conclusion: Overall, CBCT had a higher diagnostic accuracy in complex endodontic pathoses compared to PR. Nevertheless, CBCT failed to diagnose apicomarginal bone defects in 33% teeth. In evaluating the status of buccal cortical plate from CBCT images, observers could detect absence of bone better than its presence. Thus, limited FOV CBCT should be considered for selective cases where periapical radiography has diagnostic ambiguity. [ABSTRACT FROM AUTHOR]

Aim: To determine the anatomical reasons for sodium hypochlorite (NaOCl) accidents by testing whether this mishap is likely to occur in cases where the anatomical apex of the teeth fenestrates the overlying buccal cortical alveolar bone, allowing NaOCl to gain direct access to buccal soft tissues. Methodology: Following a cross‐sectional, nonrandomized design, 13 patients who suffered unintentional NaOCl accidents whilst undergoing root canal treatment were included. After remission of symptoms, the root canals were fully irrigated with an innocuous radiopaque solution (saline diluted Claritrast 300) and subsequently CBCT scanned to create a 3D‐map of the periapex and tracking of the irrigant pathway throughout the periapical tissues. An extra group of five control patients, who underwent root canal treatment with no NaOCl accident, was also CBCT‐scanned after irrigation with the tracking radiopaque solution. The anatomical relationship of the cortical bone and the root apex, as well as the distribution of irrigation solution in the periapical tissue, was associated with patients undergoing a NaOCl accident or not, using a Fisher's exact test. Results: The frequency of teeth with apical cortical fenestration was significantly higher in the NaOCl accident‐positive group, compared to the negative (P < 0.001). All 13 accident‐positive patients had an anatomical apex in direct contact with the buccal soft tissue via fenestration of the overlying cortical bone and direct contact of the foramen with the soft tissues. The radiopaque solution was distributed in the soft tissue in these cases. In contrast, accident‐negative patients had no fenestration of the buccal cortical bone and the anatomical root apex was within the cancellous bone or within a bone‐confined periapical lesion. The radiopaque solution was also found in the cancellous bone or the periapical lesion, but patients had no manifestations of a NaOCl accident. Conclusion: This quasi‐experimental cross‐sectional clinical study suggests that, in addition to the presence of the extruded NaOCl solution, a patent foramen that fenestrates the cortical bone merging into the mucosal tissue might constitute a risk for the clinical manifestation of a NaOCl accident. Preoperative 3D scans aid in anticipating when an accident is likely to occur. [ABSTRACT FROM AUTHOR]

Adequate knowledge and accurate characterization of root and canal anatomy is an essential prerequisite for successful root canal treatment and endodontic surgery. Over the years, an ever‐increasing body of knowledge related to root and canal anatomy of the human dentition has accumulated. To correct deficiencies in existing systems, a new coding system for classifying root and canal morphology, accessory canals and anomalies has been introduced. In recent years, micro‐computed tomography (micro‐CT) and cone beam computed tomography (CBCT) have been used extensively to study the details of root and canal anatomy in extracted teeth and within clinical settings. This review aims to discuss the application of the new coding system in studies using micro‐CT and CBCT, provide a detailed guide for appropriate characterization of root and canal anatomy and to discuss several controversial issues that may appear as potential limitations for proper characterization of roots and canals. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]

Aim: To determine and compare the accuracy and efficiency of a dynamic navigation system (DNS) with a freehand (FH) technique when conducting root‐end resection in a human cadaver model. Methodology: Forty roots in cadaver heads were included and divided into two groups: DNS (n = 20) and FH (n = 20). Cone beam computed tomography (CBCT) scans of all teeth were taken. The drilling path and depth were planned virtually to using the X‐guide software (X‐Nav Technologies, Lansdale, PA, USA). Osteotomy and root‐end resection were done under navigation in the DNS group, and freehand under the dental operating microscope in the FH group. Post‐operative CBCTs were taken. Linear deviations, angular deflection, time of operation and number of mishaps were compared with determine the accuracy and efficiency. Shapiro–Wilk, one‐way ANOVA and Fisher exact tests were used (P < 0.05). Results: Linear deviations, angular deflection and operation time were significantly less in the DNS group (P < 0.05). The number of mishaps was not different between the two groups (P > 0.05). Subgroup analyses revealed that the distance of >5 mm from buccal cortical plate was significantly associated with lower accuracy, increased operation time and greater incidence of mishaps in the FH group (P < 0.05), but not in the DNS group. Conclusions: The dynamic navigation system was more accurate and more efficient in root‐end resection in a cadaver model than the freehand technique. The distance of the roots from the buccal cortical plate had a significant negative impact on the accuracy and efficacy of the root‐end resection procedure when using the freehand technique. The dynamic navigation system has the potential to be a safe and reliable technological addition to endodontic microsurgery. [ABSTRACT FROM AUTHOR]

This European Society of Endodontology (ESE) position statement on surgical extrusion, intentional replantation and tooth autotransplantation represents the consensus of an expert committee, convened by the ESE. A narrative review in the International Endodontic Journal (Plotino et al. 2020, international Endodontic Journal, 53, 1636–52) formed the basis for the position statement. The review provided detailed information on the background, clinical procedures and the outcome of surgical extrusion, intentional replantation and tooth autotransplantation techniques. The aim of the current statement is to summarize the best available evidence on these clinical techniques to provide appropriate clinical guidance to undergraduate and postgraduate students, dental practitioners, clinical teachers and researchers. The current position statement will be updated by the ESE periodically to reflect new evidence as it becomes available to provide the most current treatment guidance for clinical practice. [ABSTRACT FROM AUTHOR]

The aim of a radiographic report is to provide an accurate interpretation of images to facilitate the diagnostic process, and when indicated prompt the appropriate management for the patient. It is part of the patient's clinical records. This paper describes the imaging chain involved in the cone beam computed tomography (CBCT) workflow from referring to reporting on a CBCT scan. It provides guidelines on the essential information required before and immediately after a CBCT scan is taken, and optimizing the viewing conditions. Finally, it describes a framework for a systematic, comprehensive and tailored CBCT radiographic report. It is aimed at endodontists, clinicians and radiologists reporting on CBCT scans of the dentoalveolar region. [ABSTRACT FROM AUTHOR]

Aim: To report a case involving transantral palatal root piezoelectric surgery followed by a sinus floor augmentation procedure with the purpose of minimizing and managing complications associated with sinus lining perforations and optimizing bone regeneration at the site of the surgical defect. Summary: An asymptomatic 28‐year‐old male patient with the diagnosis of chronic apical periodontitis on a previously root filled right maxillary first molar (FDI tooth 16) and second premolar (No. 15) was managed by transantral apical surgery. Cone‐beam computerized tomography (CBCT) revealed the position of the palatal root of the first molar within the maxillary sinus. The case highlights the management of the palatal root and the handling of a perforation of the Schneiderian membrane through a combination of piezosurgery and a sinus lift grafting procedure involving a second‐generation of platelet concentrates. No postoperative complications were observed. Sinus bone augmentation after a 26‐month recall period was confirmed by CBCT in the clinically asymptomatic teeth. Key learning points: The selective bone tissue cutting and enhanced visibility obtained by piezoelectric surgery in comparison with current rotary techniques make this technology the preferred tool for apical surgery when the mucosal lining of the maxillary sinus could be compromised. The wound healing and physical properties of the platelet‐rich fibrin membranes in combination with an allograft material can be considered as sinus bone graft options when a transantral approach is performed on a palatal root of a maxillary molar. A preoperative tomographic examination is essential for apical surgery using a transantral approach with sinus bone augmentation, because of the information obtained from the axial and coronal views on the CBCT scan. [ABSTRACT FROM AUTHOR]

Aim: To compare conventional radiographic and cone beam computed tomography (CBCT) findings with reference to the American Association of Endodontics and American Academy of Oral and Maxillofacial Radiology (AAE/AAOMR) joint position statement and to determine the effect of the CBCT on the initial diagnoses and treatment plans in a single‐centre Postgraduate Endodontic Programme. Methodology: The clinical CBCT scans of patients, treated at the Endodontic Department of the University of British Columbia, were reviewed for CBCT referrals by comparing them with corresponding radiographs. The features considered were periapical lesions, missed/extra canals, root fractures, complex anatomy, calcified canals and root resorption of tooth/teeth in question. Reasons for the CBCT prescriptions were assigned to 3 groups: to formulate the primary diagnosis, to confirm the diagnosis achieved by clinical examination and conventional radiographs, and to assist in treatment planning. Variables were compared statistically using chi‐square and McNemar tests. Results: A total of 128 CBCT examinations were performed on 110 patients. No CBCT examination was performed more than once on the same tooth. Overall, 76% of CBCT examinations were performed on previously root filled teeth. CBCT images revealed a significantly higher incidence of periapical lesions (P = 0.002), missed canals (P < 0.001), vertical root fractures (P = 0.004) and complex anatomy (P = 0.008) than periapical radiographs. CBCT was prescribed most frequently to assist surgical treatment planning (62%) rather than for generating a diagnosis (9%) or confirming diagnoses (29%). Both the diagnosis (P = 0.001) and the treatment plan (P = 0.005) initially made by examining periapical radiographs were altered significantly by the subsequent CBCT examination by revealing information such as new periapical lesions, missed canals or involvement of buccal or lingual cortical bone. Conclusion: CBCT examinations were prescribed mainly to assist treatment planning rather than for diagnosis. The majority of CBCT examinations were performed on previously root filled teeth. The additional information obtained from CBCT scans resulted in the alteration of the initial diagnoses as well as subsequent treatment plans in 59 out of 128 cases. [ABSTRACT FROM AUTHOR]

The chapters on surgical endodontics and auto-transplantation detail some very useful information which could provide a good resource for clinicians to refamiliarize themselves with techniques which they may not carry out frequently in practice. The first edition of the textbook of "Endodontic Advances and Evidence-Based Clinical Guidelines" by Professors Hany Ahmed and Paul Dummer provides an extremely interesting and comprehensive description of modern endodontics which will unquestionably be a valuable resource to endodontists and any practitioner with an interest in endodontics. This rounds off a thoroughly comprehensive and wide-ranging look at modern endodontics and will be of particular interest to many readers since trauma and the overuse of antibiotics can be an area of particular concern for patient management in practice. [Extracted from the article]

Aim: To evaluate the effect of various parameters of periapical lesion(s) on the amount and type of mucosal thickening using cone beam CT images. Methodology: CBCT scans of 1000 patients were evaluated retrospectively for the presence of apical lesions in maxillary posterior teeth associated with sinus mucosal thickening. The number of cases with pathological mucosal thickening was recorded and classified according to the amount and type of mucosal thickening. The parameters evaluated as the cause of mucosal thickening were the type and number of posterior teeth, number of root(s), diameter of the periapical lesion and distance between maxillary sinus and lesion. Descriptive statistics and multiple logistic regression was used for data analyses. Spearman's correlation coefficient was used for pair‐wise comparisons. Intrarater reliability was tested by Cohen's kappa. Results: Mucosal thickening associated with periapical lesions was determined in 48% of 202 cases. The most frequently detected extent of mucosal thickening was type 3 (42%), whereas flat type thickening (59%) was the most frequent type. The tooth most frequently associated with mucosal thickening was the maxillary first molar (44%). Parameters significantly affecting the extent of mucosal thickening were gender, number of roots, number of teeth with periapical lesions and diameter of periapical lesions (P < 0.05). The single parameter with an association with the type of mucosal thickening was the number of roots with an apical lesion (P < 0.05). Conclusion: Mucosal thickening associated with periapical lesions was observed in almost 50% of all mucosal thickening cases. Therefore, collaboration amongst endodontists and otolaryngologists is mandatory to provide successful treatment and prevent recurrence of maxillary sinusitis. [ABSTRACT FROM AUTHOR]

Aim: To determine if small and medium field of view (FOV) cone beam computed tomography (CBCT) adjusted grey density values can be used to distinguish between periapical cystic and solid lesions. Methodology: Fifty‐seven patients with periapical lesions having retrievable small or medium FOV CBCT images and biopsy samples were included. Two oral and maxillofacial pathologists examined the biopsy samples to provide the gold standard diagnosis of cystic or solid lesion. From the CBCT images, two independent examiners recorded the minimum adjusted grey density value of each lesion twice. Intra‐examiner and inter‐examiner reliability of the measurements were analysed, and sensitivity, specificity and accuracy of the minimum grey values in distinguishing a solid from cystic lesion were calculated. A receiver operating curve for diagnostic ability of adjusted grey density values to differentiate between periapical cystic and solid lesions was obtained, and the area under the curve (AUC) was calculated. Results: The intra‐ and inter‐examiner reliability of the grey density values of the lesions and dentine were excellent. The AUC was 0.44 (P‐value = 0.45). The adjusted grey density value with the greatest accuracy for differentiating between cystic and solid lesions had an accuracy, sensitivity and specificity of 0.54, 1.00 and 0.075, respectively. Conclusions: Small FOV CBCT adjusted grey density values obtained by the device used in the study could not distinguish between periapical cystic and solid lesions. Further developments in CBCT devices are needed to improve the accuracy of grey density measurements. [ABSTRACT FROM AUTHOR]

Aim: To evaluate the influence of various endodontic access cavity designs and the use of an operating microscope (OM) with or without ultrasonic troughing to detect middle mesial canals (MMCs) in extracted mandibular first molars. Methodology: Sixty extracted mandibular first molars were evaluated by cone beam computed tomography (CBCT) in order to detect the presence of MMCs and then divided into two groups (n = 30) with an equal proportion of 1 molar with MMC for each 3 molars. A specific access cavity design was performed for each group, either a conservative access cavity (CAC) or a traditional access cavity (TAC). Root canals were detected in three assessment stages: (i) no magnification, (ii) using an OM and (iii) using an OM together with ultrasonic troughing. Evaluations were performed on a mannequin head in an ergonomic working position. The confidence obtained in the assessment stages was portrayed by sensitivity, specificity and accuracy, calculated by the area under the ROC curve. The difference in the proportion of correct diagnoses in identifying the MMC using either CAC or TAC preparation, at each of the three stages, was checked using Cochran's Q tests. Binomial tests were performed at each stage to investigate whether there was a difference between the types of endodontic access designs to detect MMCs. Significance was set at P < 0.05. Results: Accuracy increased at each assessment stage. At the third stage, both groups provided perfect accuracy (1.00). Cochran's Q tests indicated that the confidence of MMC detection for both TAC and CAC groups (P < 0.05) increased significantly at each stage. Binomial tests demonstrated that there was no significant difference between the TAC and CAC groups, when evaluation was performed without magnification (P > 0.05), with OM (P > 0.05), or with OM associated with ultrasonic troughing (P > 0.05). Conclusion: The access cavity design did not significantly affect detection of middle mesial canals in extracted mandibular first molars placed in a mannequin. However, the use of OM increased the accuracy of the MMC identification, especially when associated with ultrasonic troughing. [ABSTRACT FROM AUTHOR]

Aim: To assess the impact of motion artefacts and motion‐artefact correction on diagnostic accuracy of apical periodontitis (AP) in CBCT images. Methodology: Based on clinical and radiographic inspection of 40 formalin‐fixated human jaw specimens, 77 roots in 45 teeth (molars and premolars), with various disease and treatment state, were selected. The specimens were mounted on a robot simulating 3‐mm movement types (nodding, lateral rotation and tremor). CBCT images with and without (controls) movements were acquired in four CBCT units: without motion‐artefact correction in Cranex 3Dx, Orthophos SL 3D, and Promax 3D Mid, and with motion‐artefact correction in Promax 3D Mid and X1. Three observers blindly assessed (i) whether the images were interpretable and (ii) if AP was present (5‐step probability index). Histopathology provided the reference standard for presence of AP. Weighted Kappa statistics described inter‐observer agreement. Estimates of diagnostic accuracy were assessed by means of receiver operator characteristic (ROC) curve analysis. Area under the curve (AUC) provided a measure of accuracy, and paired‐sample AUC difference tests compared differences amongst the CBCT units and movement types. Results: Observer agreement was substantial for control images, moderate for motion‐artefact corrected images and fair for images without motion‐artefact correction. When movement was present, motion‐artefact correction reduced the percentage of images scored as noninterpretable or with uncertain disease state (score 3 in the 5‐step probability index). Control images were not perfectly accurate (both false‐positive and false‐negative results were present; AUC 0.750–0.799). Images acquired with movement and without motion‐artefact correction (AUC 0.541–0.709) were associated with significantly lower accuracy than control images (P < 0.05). With motion‐artefact correction, accuracy was comparable to that observed in control images (AUC 0.732–0.790). Conclusions: Diagnostic accuracy of apical periodontitis in CBCT images was dependent on the presence of motion artefacts (i.e. lower accuracy associated with the presence of movement). Motion‐artefact correction systems positively influenced image interpretability and diagnostic accuracy. [ABSTRACT FROM AUTHOR]

Aim: To assess the influence of artefacts generated by metal posts on the detection of simulated internal root resorption (IRR) in adjacent teeth using cone‐beam computed tomography (CBCT) and to verify the impact of metal artefact reduction (MAR) on these cases. Methodology: CBCT images of 14 premolar teeth were acquired before and after IRR simulation using chemical and mechanical procedures, in an OP300 Maxio unit, with and without MAR. Each tooth was placed in the socket of a human mandible and scanned under three different conditions: (i) without adjacent teeth – control group; (ii) distal adjacent tooth restored with metal post; and (iii) with both adjacent teeth restored with metal post. Five oral radiologists scored the IRR detection using a 5‐point scale. Diagnostic values were obtained for the tested groups and compared using two‐way analysis of variance (α = 0.05). Results: The presence of a single adjacent tooth restored with metal post did not significantly influence the diagnostic values for IRR detection (P > 0.05). The presence of both adjacent teeth with metal posts, without MAR application, was associated with a significantly lower area under the ROC curve (Az) compared to the control (P = 0.0182). In this case, the application of MAR increased Az, leading to nonsignificant differences from the control group and the group with one adjacent restored tooth (P > 0.05). Sensitivity decreased significantly when two adjacent restored teeth were present, regardless of MAR application (P = 0.0379). Specificity was not affected by the conditions tested (P > 0.05). Conclusion: CBCT detection of IRR was impaired by artefacts only when both adjacent teeth restored with metal posts were present. In such cases, activation of MAR improved the performance on this diagnostic task. [ABSTRACT FROM AUTHOR]

Aim: First, to examine the impact of the residual volume of coronal tooth structure in posterior teeth measured with an intra‐oral scanner on the 4‐year clinical survival of root canal retreated teeth. Secondly, to assess retrospectively the effectiveness of the Dental Practicality Index (DPI) in predicting the survival of root canal retreated teeth. Methodology: A total of 156 posterior root canal treated teeth (140 patients) had baseline periapical radiographs (PA) and cone‐beam computed tomography (CBCT) scans taken prior to root canal retreatment. These teeth were followed up with a clinical examination at 1, 2, 3 and 4 years (T12, T24, T36 and T48) with periapical radiographs and CBCT images taken at T12, and PA taken at T24, T36 and T48 where appropriate. Root canal retreated teeth were dichotomized into 'survived' versus 'extracted'. Fisher's exact test was used to determine the association between the volume of remaining coronal tooth structure and the 4‐year tooth survival. The Dental Practicality Index for each tooth was established using the preoperative clinical and radiographical data. Fisher's exact test was used to establish a relationship between categorical variables, the total score of DPI vs tooth outcome. Results: The percentage of extractions associated with teeth with <29.5% remaining coronal tooth structure was 3 times higher (12.5%) compared to that of teeth with a residual tooth structure > 29.5% (3.5%), but with no significant difference (P = 0.073). There was a significant correlation between the outcome of root canal retreatments at 1 year, assessed by both PA and CBCT, and the 4‐year survival (Fisher's exact test, P = 0.007 and P = 0.001, respectively). Teeth with DPI scores ≥ 6 were more likely to be extracted than teeth with DPI score < 6 (18.8% vs. 3.9%) (Fisher's exact test, P = 0.045). Conclusion: Teeth with <30% of remaining tooth structure were associated with a survival rate above 80% and teeth with more than 30% of residual tooth structure survived in more than 94% of the cases. The radiographic outcome of root canal treatment can also help to predict tooth survival with teeth having an unfavourable outcome at 1 year more likely to be extracted within 4 years of completion of treatment. The DPI score can potentially be used to identify teeth with failed root canal treatment, which are likely to be extracted following retreatment and cuspal coverage. [ABSTRACT FROM AUTHOR]

Aim: To assess the outcomes of platelet‐rich plasma as a scaffold in regenerative/revitalization endodontics (RET) using cone beam computed tomography (CBCT) and 2‐dimensional radiographs. Methodology: Twenty‐six healthy patients with mean age of 12.66 ± 4.47, and immature permanent anterior teeth with necrotic pulps, were randomly allocated to two groups, whereby RET was performed using platelet‐rich plasma (PRP, test group) and blood clot (BLC, control group). Changes in root length (RL), root dentinal thickness (RDT), apical foramen width (AFW) and radiographic root area (RRA), were assessed using both radiographic methods, whilst changes in periapical area diameter (PAD) were assessed using CBCT, over a period of 12 months. T‐test and chi‐square/Fisher's exact tests were used to compare continuous and categorical data between BLC and PRP groups, respectively. Changes in RL, RDT, AFW, RRA and PAD were examined by comparing the two groups (PRP versus BLC) using multilevel modelling, considering the clustering effect of repeated measures of several teeth originating from the same participant. Results: Changes in RL, RDT, AFW, RRA and PAD, over time, were found to be significant for both groups. There was, however, no difference between the RET techniques (PRP versus BLC), using both radiographic and CBCT methods. The results of both assessment techniques (CBCT and 2‐dimensional radiographic methods) were highly consistent (overall ICC ranged between 0.80 and 0.94). In addition, a significant effect of baseline PAD was found on RL, RRA and AD at 12 months (RL effect = −0.68, P < 0.001; RRA effect = −1.91, P = 0.025; AD effect = 0.08, P = 0.024). Conclusion: The current study highlights successful and comparable clinical and radiographic outcomes of RET techniques using PRP and BLC. Standardized and calibrated 2‐dimensional radiographic assessment was as effective as CBCT in assessing RET outcomes; therefore, the routine use of CBCT in RET is not recommended. Although an effect of baseline periapical lesion diameter on root development outcomes, at 12 months, were observed, more studies are recommended in order to assess such an effect. [ABSTRACT FROM AUTHOR]

Aim: To explore in a laboratory setting the feasibility of using Meglumine Diatrizoate (MD) to improve the accuracy of diagnosis of cracked teeth on cone‐beam CT (CBCT) images. Methodology: Twenty‐four teeth were cracked artificially by soaking them cyclically in liquid nitrogen and hot water. The number and position of crack lines were evaluated with a dental operating microscope and used as the gold standard. The artificially cracked teeth were then examined using routine scanning (RS) and enhanced scanning (ES) modes, respectively. For the ES mode, MD was painted on the surface of the crack lines, and then, CBCT scanning with the same parameters was performed after 10 min. A radiological graduate student and an experienced radiologist evaluated the presence or absence of crack lines, respectively. The differences between the RS and ES modes were determined and assessed using McNemar's test. Inter‐examiner agreement and intra‐examiner agreement were assessed using kappa analysis. Results: Fifty‐seven crack lines were found in the 24 cracked teeth. In the RS mode, the accuracy of detection of crack lines was 23% (radiological graduate student) and 32% (experienced radiologist), whereas in the ES mode, the accuracy was 61% (radiological graduate student) and 65% (experienced radiologist). The inter‐examiner agreement was 0.693 in RS mode and 0.849 in ES mode. The intra‐examiner agreement was 0.872 and 0.949 for the radiological graduate student in RS and ES mode respectively; and one for the experienced radiologist both in RS and ES mode. Conclusions: Compared with routine scanning mode, more crack lines could be detected in enhanced scanning mode using Meglumine Diatrizoate as a contrast medium. MD could be a potential contrast medium to improve the accuracy of detection of crack lines on CBCT images. [ABSTRACT FROM AUTHOR]

Aim: To verify the diagnostic performance of an artificial intelligence system based on the deep convolutional neural network method to detect periapical pathosis on cone‐beam computed tomography (CBCT) images. Methodology: images of 153 periapical lesions obtained from 109 patients were included. The specific area of the jaw and teeth associated with the periapical lesions were then determined by a human observer. Lesion volumes were calculated using the manual segmentation methods using Fujifilm‐Synapse 3D software (Fujifilm Medical Systems, Tokyo, Japan). The neural network was then used to determine (i) whether the lesion could be detected; (ii) if the lesion was detected, where it was localized (maxilla, mandible or specific tooth); and (iii) lesion volume. Manual segmentation and artificial intelligence (AI) (Diagnocat Inc., San Francisco, CA, USA) methods were compared using Wilcoxon signed rank test and Bland–Altman analysis. Results: The deep convolutional neural network system was successful in detecting teeth and numbering specific teeth. Only one tooth was incorrectly identified. The AI system was able to detect 142 of a total of 153 periapical lesions. The reliability of correctly detecting a periapical lesion was 92.8%. The deep convolutional neural network volumetric measurements of the lesions were similar to those with manual segmentation. There was no significant difference between the two measurement methods (P > 0.05). Conclusions: Volume measurements performed by humans and by AI systems were comparable to each other. AI systems based on deep learning methods can be useful for detecting periapical pathosis on CBCT images for clinical application. [ABSTRACT FROM AUTHOR]

Aim: To compare surgical time, bevel angle and site volumetric profiles of osteotomy and resection accomplished by targeted endodontic microsurgery (TEMS) and traditional endodontic microsurgery (EMS) in a surgical simulation model. Methodology: An 80x80‐mm cone beam computed tomography (CBCT) file was imported into Mimics software where artificial periapical lesions were created encompassing twelve root apices. Maxillary and mandibular models were 3D‐printed. TEMS surgical guides were designed and 3D‐printed for each surgical site. Three board‐certified endodontists used the original CBCT to plan and perform EMS on models of six maxillary and six mandibular teeth. Next, the same endodontists performed TEMS on duplicate 3D‐printed models for the same teeth. All surgeries were timed. Postoperative CBCT images of experimental models were made and imported into Amira software for measurement of bevel angle and site volumetric profiles. Paired t‐tests compared the mean differences between EMS and TEMS groups. A Bonferroni correction determined data to be significant at P < 0.004. Results: TEMS significantly reduced surgical time (P < 0.00001), had bevel angles more closely approaching zero degrees (P < 0.01) and had significantly less volume of over‐resection (P < 0.001) and length of root resection (P < 0.01). Conclusions: In this surgical simulation scenario, TEMS provided more efficient completion of osteotomy and resection, with a more appropriate root‐end resection volume and bevel angle. [ABSTRACT FROM AUTHOR]

Aim: To analyse the prevalence of periapical lesions and their association with previous root canal treatment, root canal filling length and type of coronal restoration using in vivo cone‐beam computed tomographic (CBCT) assessment. Methodology: A global sample of 20 836 teeth, with a combined total of 27 046 roots, from 1160 patients, was analysed via CBCT assessment in eight health centres. Each tooth was evaluated by one out of five examiners after having performed a defined calibration procedure on the basis of 319 teeth. Intra‐ and inter‐rater reliability tests were performed. Each tooth was classified according the tooth number, presence/absence of periapical lesions, presence/absence of previous root canal treatment, length of root canal filling (short, good or overfilling) and type of coronal restoration. The z‐test for proportions was used to analyse differences between tooth subgroups, and an odds ratio was determined in order to analyse the association between treatment status and periapical lesions. A P < 0.05 was considered significant. Results: At a tooth level, the overall prevalence of periapical lesions in the sample was 10.4%. Maxillary teeth were associated with a significantly larger percentage of lesions (13.1%), whilst maxillary first molars had the greater proportion of lesions (21.2%). The prevalence of periapical lesions was significantly larger in root filled teeth (55.5%), short root canal fillings (72.7%) and in teeth restored with crowns (46.1%). At a root level, the mesiobuccal roots of both maxillary first molars had a tendency for a larger percentage of periapical lesions. Conclusion: History of root canal treatment, root canal filling length and type of coronal restoration influenced the presence of periapical lesions. Molars were more commonly associated with periapical lesions on root filled teeth, particularly those with short root fillings and those with crowns. [ABSTRACT FROM AUTHOR]

Aim: To evaluate the influence of the metal artefact reduction (MAR) tool in the diagnosis of fractured instruments in root canals of extracted mandibular molars, with or without root canal fillings. Methodology: The root canals of 31 mandibular molars were divided into four groups: (i) the control group, without root fillings; (ii) the fracture group, without fillings and with fractured files; (iii) the fill group, with root filling; and (iv) the fill/fracture group, root filled and with fractured files. The following instruments were used as fractured endodontic instruments: stainless steel hand files, NiTi reciprocating files and NiTi rotary files. Each tooth was inserted in a dry mandible to obtain cone‐beam computed tomography (CBCT) images using a CBCT OP300 3D Maxio (Instrumentarium Dental, Tuusula, Finland) and Picasso Trio (Vatech, Hwaseong, Republic of Korea), with and without application of the MAR tool. All images were evaluated by three radiologists for the presence or absence of fractured files on a 5‐point scale. The diagnostic accuracy (area under ROC curve) was calculated. Image noise was measured in regions of trabecular and cortical bone and soft tissue. The comparison between the ROC curve values with the MAR tool enabled or disabled was performed using a t‐test. A t‐test was also employed for comparing image noise when the MAR tool was enabled and disabled. The significance level was set at 5%. Results: The use of the MAR tool did not influence the diagnostic accuracy for identifying fractured endodontic instruments in root canals with and without fillings in both CBCT systems (P > 0.05), nor did it influence the image noise (P > 0.05). Conclusions: The MAR tool on these two devices did not increase the detection of fractured endodontic instruments and did not reduce image noise using extracted mandibular molars. Therefore, the MAR tool is not recommended for evaluation of fractured endodontic instruments in teeth with and without root fillings in mandibular molars. [ABSTRACT FROM AUTHOR]

The article focuses on the use of periapical radiography in judging the outcomes of endodontic therapy. It states that endodontic procedures are considered safe and effective in preventing and healing periodontitis and managing associated risks with periodontitis. It comments on periapical radiolucencies that cone-bean computed tomographic imaging can detect and suggests that tooth survival and other minimalist patient-based outcomes may be insufficient in dealing with apical periodontitis.

Aim: To measure the coronal root canal morphology of permanent mandibular first molars using 3D coordinates for more precise conservative endodontic cavity preparation. Methodology: In total, 57 cone beam computed tomography (CBCT) images of sound mandibular molars with fully formed apices without previous endodontic treatment were taken from 33 patients aged 16 to 75 years. The CBCT machine (MCT‐1[EX‐2F], J. Morita Manufacturing Corp, Kyoto, Japan) provided 14‐bit greyscale images with the voxel size of 0.125 mm. All images were taken at 80 kV and 5.0 mA, with a 17‐s exposure time, which were then reconstructed in 3D models and viewed by an endodontist. The gender of the patients and the tooth position, and number of root canals, were recorded. The landmarks of coronal root canals were determined, then the distribution of landmarks, maximum curvature in the axial direction and curvature directions in the horizontal direction of coronal root canals were measured. Distributions of landmarks were analysed using a spatial statistics method. Data about curvature were compared using a t test. Results: Overall, the distribution of root canal orifices and the centre of the canal primary curve were more centralized than other landmarks. The landmarks were located more mesiobuccally to the centre of the occlusal plane of mandibular first molars. Specifically, the measurements of the maximum curvature of coronal root canals in the axial direction were as follows: in 3‐canal teeth, the average angles of curvatures were 22°,23°,15° for mesiobuccal (MB), mesiolingual (ML) and distobuccal (DB) canals, respectively; in 4‐canal teeth, the average angles of curvatures were 24°,26°,15°,22°for MB, ML, DB and distolingual (DL) canals, respectively. The degrees of coronal root canal curvatures in the horizontal direction were as follows: in 3‐canal teeth, the average angles of curvatures were −8°,47°,−2° for MB, ML and DB canals, respectively; in 4‐canals teeth, the average angles were −11°,50°,−28°,45° for MB, ML, DB and DL canals, respectively. Statistically, there was no reliable side or sex difference in any of the measurements (P > 0.05). Conclusions: In permanent two‐rooted mandibular first molars, the coronal canals clustered in the direction of the mesiobuccal side of the occlusal surface of the teeth. [ABSTRACT FROM AUTHOR]

Background: The novel concept of guided endodontics has been reported as an effective method to obtain safe and reliable results in root canal treatment. Aim: To evaluate by means of a systematic review the clinical applications, accuracy and limitations of guided endodontic treatment. Data sources: A search of the literature was performed on PubMed, Embase, Web of Science and Cochrane Library databases, until 25 April 2019. No language or year restrictions were applied. Study eligibility criteria: Articles that answered the research question, including case reports, in vitro and ex vivo studies were included. Data extraction was performed independently by two reviewers. Study appraisal: Quality assessment was done using STROBE, CARE and Modified CONSORT guidelines for observational, case reports and pre‐clinical studies, respectively. Results: A total of 22 articles, including fifteen case reports, six pre‐clinical studies (in vitro and ex vivo studies) and one observational study, were included. Limitations and Conclusions: Even though the level of evidence is low, and the methodology described among studies heterogeneous, all articles describe guided access cavity preparation and guided surgery as being highly accurate and successful techniques when comparing the drilled path to the planned treatment. More studies with a larger number of patients are necessary to obtain significant conclusions. [ABSTRACT FROM AUTHOR]

Aim: To report the most common terminology used in titles of scientific papers published in the International Endodontic Journal (IEJ) and Journal of Endodontics (JOE) between 1980 and 2019 and to identify the most‐cited papers in these journals. Methodology: The Web of Science database was searched to retrieve all the manuscripts published in the IEJ and JOE between 1980 and 2019. The articles were analysed using the VOS viewer software and the terms within the titles extracted. The top‐10 terms were categorized according to the number of occurrences and the decade of publication. Maps were created using the text data for each decade of publication. Classic papers were identified when the number of citations was >400. During the same period of time, highly cited studies were identified including the authors, institutions and countries associated with these papers. Results: Terms such as canal, molar and periapical lesion were the most commonly used in titles between 1980 and 1999. The terms instruments, expression, case report and cell were the most often terms used between 2000 and 2019. During the last 10 years, an increase in the number of reviews and papers on cone beam computed tomography occurred. The organizations with the largest number of citations in each decade were University of São Paulo, University College London, Loma Linda University and United States Army. The country with the largest number of citations and greatest number of top 10 and top 100 manuscripts was the United States. A paper had to be associated with more than 167 citations to be included in the top‐100 most‐cited list; at least 14 papers met the criteria to be categorized as a citation classic (>400 citations). Conclusion: While many diverse areas of endodontics have been explored in the last 40 years within the IEJ and JOE, only a relatively few topics are highly cited and can be considered as classics. [ABSTRACT FROM AUTHOR]

This Position Statement represents a consensus of an expert committee convened by the European Society of Endodontology (ESE) on the use of Cone Beam Computed Tomography (CBCT) in Endodontics. This paper is an update of the ESE CBCT position statement which was published in 2014 (European Society of Endodontology 2014, https://doi.org/10.1111/iej.12267). Recent review articles provide more detailed background information and the basis for this position statement. It is intended that this position statement will be updated at least every 4‐5 years to keep abreast of relevant research. The aim of this paper is to provide clinicians with evidence‐based guidance on the application of CBCT in Endodontics. Since 2014, there has been an increase in the number of clinical studies confirming the positive impact of CBCT on treatment planning, decision‐making when reviewing cases and reduced practitioner stress levels. [ABSTRACT FROM AUTHOR]

Aim: To assess retrospectively the clinical and radiographic outcomes of retrograde root canal retreatment (RRR) and to identify possible prognostic factors that may affect the outcome. Methodology: Clinical records and radiographs were collected from patients who had undergone RRR between 2009 and 2016 and had a 1‐year follow‐up. All surgical procedures were performed by a single endodontist. The RRR technique involved minimal root‐end resection and maximal length retrograde preparation using pre‐bent ultrasonic files. Outcomes were categorized as complete, incomplete, uncertain or unsatisfactory healing based on clinical and radiographic findings. The complete and incomplete healing cases were pooled and considered as successes, while uncertain and unsatisfactory cases were considered failures. Prognostic factors were analysed using univariate analysis and multivariate logistic regression. Results: In total, 575 patients with 721 teeth were included. The overall success rate was 91.8%. None of the prognostic factors (including age, gender, size of periapical radiolucency and isthmus presence) had a significant influence on the outcome (P > 0.05). Univariate analysis revealed tooth type had a significant influence on outcome (P = 0.008) with mandibular incisors having a significantly lower success rate (71.4%). Multivariate analysis using logistic regression revealed that the only variable with a significant association to the outcome was retrograde preparation length (P = 0.016, odds ratio = 1.299 (1.050, 1.607), C.I. = 95%)), i.e. the longer the retrograde preparation, the better the outcome. Conclusions: Retrograde root canal retreatment was successful in 91.8% of cases. This predictable success rate was achieved while minimizing root‐end resection and maximizing retrograde canal preparation length. [ABSTRACT FROM AUTHOR]

Aim: This observational cohort study aimed: (i) to determine retrospectively after a 1‐ to 12‐year follow‐up period, the strength and independence of the association of various patient‐, tooth‐ and treatment‐related prognostic variables with the outcome of root canal treatment in patients with pre‐therapeutic apical periodontitis; and (ii) to establish the concordance between those predictors evaluated by both cone‐beam computed tomography (CBCT) and digital periapical radiography (DPR). Methodology: The study cohort included 125 teeth in 84 individuals. The postoperative clinical signs/symptoms, plus DPR/CBCT‐PAI estimations, were used to determine the healing outcome. For statistical analysis, results were dichotomized into completely healed periapical structures versus persistent disease cases. The association between candidate predictor variables with persistent disease was analysed individually and adjusted for confounders using a multivariate binary logistic regression model. Results: The success rate was 53.6%. After logistic regression analysis, mandibular tooth location, periapical lesion size >10 mm, poor quality of the coronal restoration, lack of magnification/illumination, lack of disinfection of gutta‐percha, time elapsed to definitive coronal restoration >1 week and poor density of root canal filling remained as robust predictors of failures. Concordance between DPR and CBCT scores varied from moderate to almost perfect agreement. Conclusions: The findings of this study suggest that several tooth‐ and treatment‐related predictor variables, including tooth location, periapical radiolucency size, quality of the coronal restoration, magnification/illumination, disinfection of gutta‐percha, time elapsed to definitive coronal restoration, as well as, the density of root canal filling may act strongly and independently for determining the root canal treatment outcome in teeth with pre‐therapeutic apical periodontitis. [ABSTRACT FROM AUTHOR]

Background and aim: To perform a systematic review of anatomical studies using cone beam computed tomography (CBCT) to assess the influence of demographic factors (age, gender and geographic region) on the prevalence of C‐shaped canal anatomy in maxillary molars, mandibular premolars and molars. Data sources: A search was conducted between May and August 2018 in four electronic databases and five peer‐reviewed journals. The authors of included articles were also contacted for additional studies and the bibliographic references hand‐searched. Study eligibility criteria, participants and interventions: The research protocol was previously registered in the International Prospective Register of Ongoing Systematic Reviews (CRD42018095201) and included defined inclusion/exclusion criteria. Prevalence studies on C‐shaped canal anatomy in maxillary molars, mandibular premolars and molars were searched. Study appraisal and synthesis methods: The selected studies were submitted to full‐text analysis and critical appraisal by two evaluators using the Joanna Briggs Institute Critical Appraisal tool. The final group of papers (n = 25) were pooled and forest plots with proportions and odds ratio with a 95% confidence interval performed. Meta‐regression was undertaken to evaluate possible sources of heterogeneity and funnel plot visual analysis to assess publication bias. Results: The included studies reported data on 25 445 teeth of 13 142 patients. A significant difference in the average prevalence proportion of C‐shaped configuration was observed between mandibular first (0.3%; 0.1–0.6%) and second (12%; 10.3–13.7%) molars (P < 0.05). No significant difference in the prevalence of C‐shaped configurations was observed comparing males (13.5%; 8.8–18.3%) and females (20.5%; 13.7–27.4%) in mandibular second molars (P > 0.05), although males were associated with significantly lower odds (0.573; 0.511–0.641) (P < 0.05). The pooled proportion of C‐shaped anatomy in mandibular second molars in East Asian countries (39.6%; 36.0–43.1%) was significantly higher compared with other regions. Limitations: Because of the limited number of studies, no statistical analysis was performed for maxillary molars and mandibular premolars. Conclusion: Meta‐analysis revealed that gender and geographic region may act as a confounding factor for the prevalence of C‐shaped anatomy in mandibular second molars, whilst age did not influence the prevalence of C‐shaped configurations in this tooth group. Knowing these preoperative factors would help to anticipate complex morphologies in clinics. [ABSTRACT FROM AUTHOR]