Prevalence of technical errors and periapical lesions in a sample of endodontically treated teeth: a CBCT analysis

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

AIM

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

METHODOLOGY

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

RESULTS

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

CONCLUSIONS

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

A system for automatic classification of endodontic treatment quality in CBCT

OBJECTIVES

An evaluation of the effectiveness of a new computational system proposed for automatic classification, developed based on a Siamese network combined with Convolutional Neural Networks (CNNs), is presented. It aims to identify endodontic technical errors using Cone Beam Computed Tomography (CBCT). The study also aims to compare the performance of the automatic classification system with that of dentists.

METHODS

One thousand endodontically treated maxillary molars sagittal and coronal reconstructions were evaluated for the quality of the endodontic treatment and the presence of periapical hypodensities by three board-certified dentists and by an oral and maxillofacial radiologist. The proposed classification system was based on a Siamese network combined with EfficientNet B1 or EfficientNet B7 networks. Accuracy, sensivity, precision, specificity, and F1-score values were calculated for automated artificial systems and dentists. Chi-square tests were performed.

RESULTS

The performances were obtained for EfficienteNet B1, EfficientNet B7 and dentists. Regarding accuracy, sensivity and specificity, the best results were obtained with EfficientNet B1. Concerning precision and F1-score, the best results were obtained with EfficientNet B7. The presence of periapical hypodensity lesions was associated with endodontic technical errors. In contrast, the absence of endodontic technical errors was associated with the absence of hypodensity.

CONCLUSIONS

Quality evaluation of the endodontic treatment performed by dentists and by Siamese Network combined with EfficientNet B7 or EfficientNet B1 networks was comparable with a slight superiority for the Siamese Network.

CLINICAL RELEVANCE

CNNs have the potential to be used as a support and standardization tool in assessing endodontic treatment quality in clinical practice.

Morphometric relationships in mesio-buccal roots of maxillary first molars in Saudi subpopulation: A CBCT study

This CBCT-based study analysed morphometric relationships in Mesio-Buccal (MB) roots of maxillary first molars (MFM). 133 MFM with two MB canals were assessed and classified using Vertucci's classification. MB roots' length and MB1-MB2 canals inter-orifice distances (IOD) were noted. The data were analysed using SPSS software. The most frequently present canal was type IV (59.4%) followed by type II (40.6%). Mean MB roots' length for canals exhibiting type IV was 9.26 ± 0.21 mm and of those exhibiting type II was 12.8 ± 0.42 mm. Statistically significant relationship was found between MB root length and canal type. Mean IOD for type II and type IV canals was 2.4 ± 0.47 and 3.8 ± 0.21 mm, respectively. Statistically significant relationship was found between IOD and canal type. Length of MB root and IOD had a significant association with canal type present in MFM. This knowledge can enhance clinicians' understanding of canal morphology which can increase predictability and success rate of endodontic treatment.

Can maxillary molar dimensions predict the presence of the second mesiobuccal canal?

OBJECTIVE

To evaluate the potential of maxillary molar dimensions as predictors of the presence of the second mesiobuccal (MB2) canal.

METHODS

Micro-computed tomography scans were obtained from 47 maxillary molars, out of which 26 had the MB2 canal. The distance between root canals, extension of the canals, and thickness of surrounding dentin were obtained from axial images at the furcation level, 3 mm from the apex, and 5 mm from the apex. The association between the measurements and the presence of the MB2 canal was assessed using multiple logistic regression and odds ratio.

RESULTS

At the furcation level, the bucco-palatal extension of the MB1 canal significantly decreased the chance of the presence of the MB2 canal. Regarding the thickness of surrounding dentin measurements, the mesial and distal aspects of the MB1 canal at 3 mm from the apex were statistically significant to decrease and increase the chance of presence of the MB2 canal, respectively. Regarding the extension of the canals, only buccal-palatal extension seems to decrease the chance of the presence of the MB2 canal.

CONCLUSION

The presence of the MB2 canal in the mesiobuccal root of maxillary molars is associated with the bucco-palatal extension and surrounding dentin thickness of the first mesiobuccal canal, and seems to be unrelated to the dimensions of the distobuccal and palatal roots.

A retrospective study of initial root canal treatment failure in maxillary premolars via using cone-beam computed tomography

BACKGROUND

This case-series study examined canal morphology and common factors for endodontic failure in maxillary first and second premolars that were referred for retreatment owing to clinical symptoms or radiographic signs.

METHODS

Records were retrospectively searched using Current Dental Terminology codes to identify maxillary first and second premolars with endodontic failure. Periapical and cone-beam computed tomographic images were examined to determine Vertucci classifications and suspected factors related to treatment failure.

RESULTS

A total of 235 teeth from 213 patients were included for evaluation. The following Vertucci classification of canal configurations were observed for maxillary first and second premolars: type I (1-1) (4.6% and 32.0%, respectively), type II (2-1) (15.9% and 27.9%, respectively), type III (2-2) (76.1% and 36.1%, respectively), type IV (1-2) (0% and 2%, respectively), and type V (3) (3.4% and 2%, respectively). More treatment failures were noticed in maxillary second premolars than first premolars and in females than in males. The 4 most common factors related to failure were inadequate filling, restorative failure, vertical root fracture, and missed canals. Missed canals were more frequently identified in maxillary second premolars (21.8%) than first premolars (11.4%) (P = .044).

CONCLUSIONS

Multiple factors are associated with primary root canal treatment failures in maxillary premolars. Variations in canal morphology appear to be underappreciated in maxillary second premolars.

PRACTICAL IMPLICATIONS

Maxillary second premolars have more complicated canal configurations than first premolars. Besides adequate filling, clinicians should give extra attention to anatomic variability in second premolars owing to higher failure incidence.

Can the detection of second mesiobuccal canals be enhanced based on the volume of adjacent canals?

OBJECTIVES

The purpose of this study was to evaluate whether the presence of the second mesiobuccal (MB2) canal is related to volumetric differences on the adjacent canals of maxillary molars.

DESIGN

Forty-seven maxillary first and second molars with and without the MB2 canal were individually scanned using microcomputed tomography (micro-CT). The volume of each canal was measured by an evaluator with experience in micro-CT analysis. The intraclass correlation coefficient (ICC) was obtained. Multiple logistic regression and odds ratio was calculated. To compare the volume of canals in molars with and without MB2, the Mann-Whitney test was applied (α = 0.05).

RESULTS

The intra-examiner reproducibility was almost perfect (ICC=0.97). Multiple logistic regression demonstrated that the volume of the mesiobuccal (MB1) canal can possibly act as a predictor of the presence of the MB2 canal. It was also found that the MB1 canal volume is larger in molars without the MB2 canal (p = 0.01). No statistically significant difference was observed in the adjacent canals (p > 0.05).

CONCLUSIONS

Despite the challenging detection of the presence of MB2 canals, clinicians should be aware that MB1 canals of reduced volume are highly suggestive of their presence.

Root Canal Configuration and Its Relationship with Endodontic Technical Errors and Periapical Status in Premolar Teeth of a Saudi Sub-Population: A Cross-Sectional Observational CBCT Study

Endodontic technical errors are the foremost cause of treatment failure. A thorough understanding of root canal configuration (RCC) is essential to prevent these iatrogenic errors. This study used CBCT images to determine the association between root canal configuration, endodontic technical errors, and periapical status. CBCT images of 101 patients, including total of 212 obturated premolars (256 canals) were assessed. RCCs were classified according to the Vertucci system. The presence of endodontic errors and periapical lesions associated with each RCC was noted. Presence or absence of coronal restoration and its association with periapical radiolucency was recorded. The most frequent RCC was Type I (199 cases; 77.73%), followed by Type II (26 cases; 10.15%), Type IV (22 cases; 8.59%), Type V (4 cases; 1.56%), Type III (4 cases; 1.56%), and Type VI (1 case; 0.39%). Under-filling and non-homogeneous filling were the most common technical errors. Prevalence of periapical radiolucency was 81% in the presence of technical errors. The absence of coronal restoration caused apical lesions in 93% of cases. The frequency of endodontic technical errors increased as the root canal configurations became more complex. Periapical lesions occurred more often in teeth with endodontic errors and/or absent coronal restoration.

Cone-beam computed tomographic evaluation of the root canal anatomy of the lower premolars and molars in a Brazilian sub-population

Purpose

This study evaluated anatomical variations in the root canals of the lower premolars and molars in a Brazilian sub-population using cone-beam computed tomography (CBCT).

Materials and Methods

In total, 121 CBCT images of patients were selected from a database. All images contained lower first and second premolars and molars on both sides of the arch, fully developed roots, and no treatment, resorption, or calcifications. In each image, the root canals of the lower premolars and molars were evaluated according to the Vertucci classification in On-Demand 3D software in the multiplanar reconstruction with dynamic navigation. Twenty-five percent of the images were re-assessed to analyze intraobserver confidence with the kappa test. Data were statistically evaluated with linear regression to evaluate the correlations of anatomic variations with age and sex, and the Wilcoxon test to analyze the laterality of variations, with a significance level of 5%.

Results

The intraobserver agreement (0.94) was excellent. In general, the root canals of lower premolars and molars showed a higher prevalence of type I than other Vertucci classification types, followed by type V in premolars and type II in molars. When the molar roots were evaluated separately, type II was more frequent in mesial roots and type I in distal roots. Although age showed no correlations with the results, sex and laterality showed correlations with tooth 45 and the lower second premolars, respectively.

Conclusion

The lower premolars and molars of a Brazilian sub-population showed a wide range of root canal anatomic variations.

Middle mesial root canals in mandibular molars: prevalence and correlation to anatomical aspects based on CBCT imaging

OBJECTIVES

To determine the prevalence of middle mesial root canal (MMC) in a Brazilian subpopulation, verify whether its presence is related to anatomical characteristics of the tooth, and propose a classification using cone-beam computed tomography (CBCT).

METHODS

CBCT scans of 284 patients were evaluated by 2 radiologists to determine the presence of the MMC in mandibular first and second molars. Subsequently, the mesiodistal and buccolingual measurements of the mesial roots were obtained; the measurements between the root canals, and from MMC to the mesiobuccal canal and to the mesiolingual canal were also obtained. The MMC was classified according to its relationship with mesiobuccal and mesiolingual canals. The data were analyzed using χ2 and Fisher's exact test, multiple logistic regression analysis, Student's t-test, κ and intraclass correlation coefficient (p < 0.05).

RESULTS

The intraexaminer agreements for the presence of the MMC and the measurements were considered almost perfect (0.953 and 0.999, respectively). Of 216 mandibular first molars, 11.1% had the MMC, and of 228 mandibular second molars, only 1.75% had the MMC. The presence was significant higher in the mandibular first molar (p < 0.0001). The buccolingual measurement and the measurement between mesiobuccal and mesiolingual canals were higher in teeth with MMC (p = 0.024 and p = 0.005, respectively). It was possible to classify the configuration of MCC into four types: independent (60.7%), confluent (14.3%), mesiolingual confluent (14.3%), and mesiobuccal confluent (10.7%).

CONCLUSIONS

The prevalence of MMC is more pronounced in mandibular first molars and anatomical measurements, such as greater measurement between mesiobuccal and mesiolingual canals, may alert clinicians to its presence. It was found four types of configurations of MMC.

Automatic Classification System for Periapical Lesions in Cone-Beam Computed Tomography

Imaging examinations are of remarkable importance for diagnostic support in Dentistry. Imaging techniques allow analysis of dental and maxillofacial tissues (e.g., bone, dentine, and enamel) that are inaccessible through clinical examination, which aids in the diagnosis of diseases as well as treatment planning. The analysis of imaging exams is not trivial; so, it is usually performed by oral and maxillofacial radiologists. The increasing demand for imaging examinations motivates the development of an automatic classification system for diagnostic support, as proposed in this paper, in which we aim to classify teeth as healthy or with endodontic lesion. The classification system was developed based on a Siamese Network combined with the use of convolutional neural networks with transfer learning for VGG-16 and DenseNet-121 networks. For this purpose, a database with 1000 sagittal and coronal sections of cone-beam CT scans was used. The results in terms of accuracy, recall, precision, specificity, and F1-score show that the proposed system has a satisfactory classification performance. The innovative automatic classification system led to an accuracy of about 70%. The work is pioneer since, to the authors knowledge, no other previous work has used a Siamese Network for the purpose of classifying teeth as healthy or with endodontic lesion, based on cone-beam computed tomography images.

Evaluation of Root Anatomy and Canal Configuration of Human Permanent Maxillary First Molar Using Cone-Beam Computed Tomography: A Systematic Review

The aim of this paper is to review the literature on root canal configuration (RCC) and the frequency of occurrence of a second mesiobuccal canal (MB) in human permanent maxillary first molars where cone-beam computed tomography (CBCT) is used. Online electronic databases such as PubMed-Medline, Embase, Scopus and Cochrane Library were searched using appropriate keywords from the earliest available date until 12th June 2022, without restriction on language. In the mesiobuccal root, type I was the most frequent (33.29%), followed by types II and IV (27.18% and 26.36%, respectively). Moreover, 68.2% of maxillary first molars had a second MB canal. For both the distobuccal and palatal roots, type I was the most prevalent, with 99.08% and 97.83% occurrence, respectively. All other types were infrequent. Type I RCC is most frequent in all the roots of the maxillary first molars. Hence, care must be taken during biomechanical preparation of the MB roots.

Dislodgement pushout resistance of five bioceramic root-end filling materials

This study evaluated the dislodgement push-out resistance of five bioceramic materials. One hundred single-rooted teeth with one canal had the apical 3 mm and crown resected to create a 14 mm standardized length. The canals were instrumented to an apical size 80 with a 3 mm root-end preparation made with ultrasonic diamonds. The prepared roots were randomly divided into 5 root-end restorative groups (n=20). ProRoot MTA, Biodentine, EndoSequence Root Repair Material, EndoSequence Fast Set Putty, and EndoSequence BC Sealer with each material placed following manufacturer's instructions and stored at 100% humidity for 2 weeks. An apical-to-coronal static testing load with the identified dislodgement force converted into MPa with mean results analyzed with Kruskal-Wallis and Dunn's post hoc tests (α=0.05). ProRoot MTA and Biodentine displayed similar push-out stress resistance and exhibited significantly greater stress resistance than the similar Endosequence materials. However, all materials failed cohesively and were not dislodged from the root canal surface.

Association between second mesiobuccal canal and apical periodontitis in retrospective cone‐beam computed tomographic images

This retrospective cone-beam computed tomography study aimed to investigate the possible associations of apical periodontitis (AP) with missed/unmissed second mesiobuccal (MB2) canals. MB2 canals and AP were investigated in 257 endodontically treated and 673 untreated maxillary molars, and the former were analyzed regarding missed/unmissed MB2 canals. The chi-squared test and odds ratio (OR) were used for statistics. The prevalence of MB2 canals in maxillary first molars was higher than that in second molars (p = 0.001). MB2 canals were 1.751 times more common in males than in females (OR: 1.751; 95% CI: 1.334-2.297), with a significant difference in the 18-39 age groups (p = 0.005). The risk for AP was 5.5 times greater in endodontically treated maxillary molars with missed MB2 canals than in those with unmissed MB2 canals (p = 0.012) (OR: 5.5, 95% CI: 1.549-19.527). The findings of this study reveal that the likelihood of the MB2 canal is higher in the maxillary first molars of young adult males.

Is the quality of root canal filling obtained by cone-beam computed tomography associated with periapical lesions? A systematic review and meta-analysis

AIM

To evaluate the influence of root canal filling quality on periapical lesion status using cone-beam computed tomography (CBCT).

MATERIALS AND METHODS

The bibliographic search was conducted in electronic databases of PubMed, Embase, Scopus, and Web of Science without restrictions related to the year of publication and language. Inclusion criteria were prospective or retrospective cohort studies that followed periapical pathosis for, at least, 1 year. Three reviewers independently evaluated the eligibility for inclusion, extracted data, and assessed the risk of bias. The quality of the studies was based on the Newcastle-Ottawa Scale. This meta-analysis was performed to evaluate the quality of treatment by the homogeneity and apical extension of the filling.

RESULTS

Of the 1179 studies initially recovered, six cohort studies were included, out of which four were considered with a low risk of bias. The results showed that the absence of gaps in the filling reduced the chance of unhealed periapical lesions by 2.39 times (RR = 2.39; 95% CI: 1.62-3.53; p < 0.00001; I² = 55%). An apical filling extension of 0-2 mm below the apex also contributed significantly to the absence of unhealed periapical lesions (RR = 1.49; 95% CI: 1.15-1.94; p = 0.003; I² = 2%).

CONCLUSION

The homogeneity and apical extension of the filling influenced the presence of unhealed periapical lesions in endodontically treated teeth evaluated using CBCT.

CLINICAL RELEVANCE

Apical extension of the filling ranging between 0 and 2 mm short of the apical foramen and the homogeneity of the filling without gaps are directly related to the success rate of root canal treatment.

Morphological characteristics of the mesiobuccal root in the presence of a second mesiobuccal canal: a micro-CT study

Objectives

This study investigated the internal morphology of mesiobuccal (MB) roots of maxillary molars with a second mesiobuccal (MB2) canal.

Materials and Methods

Forty-seven maxillary first or second molars from Brazilians were scanned using micro-computed tomography. The following measurements were obtained from the MB roots: root thickness, root width, and dentin thickness of the buccal aspect of the first mesiobuccal (MB1) canal, between the MB1 and MB2 canals, and the palatal aspect of the MB2 and MB1 canals at 3 mm from the root apex and in the furcation region. For statistical analysis, the Student’s t-test and analysis of variance with the post-hoc Tukey test were used (α = 0.05).

Results

In maxillary molars with an MB2 canal, MB roots were significantly thicker (p = 0.0014) and narrower (p = 0.0016) than in maxillary molars without an MB2 canal. The dentin thickness of the palatal aspect of the MB1 canal was also significantly greater than that of MB roots without an MB2 canal at 3 mm from the root apex (p = 0.0007) and in the furcation region (p < 0.0001). In the furcation region of maxillary molars with an MB2 canal, the dentin thickness between the MB1 and MB2 canals was significantly smaller than that in the buccal and palatal aspects (p < 0.0001).

Conclusions

The internal morphology of MB roots of maxillary molars with an MB2 canal revealed differences in dentin thickness, root diameter, and distance between the canals when compared with maxillary molars without an MB2 canal.

The quality of root canal treatment and periapical status of permanent teeth in Turkish children and teens: a retrospective CBCT study

OBJECTIVE

This study aimed to assess the quality of root canal fillings and the prevalence of periapical radiolucencies in the permanent teeth of 6-18 year-old Turkish children.

METHODS

CBCT images of 150 patients' 235 teeth with a mean age of 16.0 ± 2.06 years were included. Root development stage, quality of root canal filling, the presence and severity of periapical radiolucencies, and their relationship with anatomical structures were recorded. Correlations between the quality of root canal filling, periapical lesion, and lesion size were assessed using regression analyses.

RESULTS

A total of 235 teeth (528 root canals) were evaluated. 65.5% of root canals had periapical lesions. Immature roots and mandibular teeth had the highest prevalence and the largest size of periapical radiolucencies (p < 0.05). Overfilling (n = 52), underfilling (n = 93), unfilled (n = 46), inhomogeneously filled (n = 113) root canals and poor coronal restoration (n = 85 teeth) were observed in terms of technical failures of endodontic treatment. The quality of endodontic treatment was associated with the presence of periapical lesion and lesion size (p < 0.05). Teeth with under-filled, overfilled or inhomogeneously filled root canals and poor coronal restoration had a periapical lesion larger than 5 mm (p < 0.05). Immature teeth were most associated with the presence of lesion (OR = 4.07) and the lesion size > 5 mm (OR = 3.71).

CONCLUSION

The prevalence of periapical radiolucencies in young permanent teeth showed an increase when the tooth was an incisor, had incomplete root development, or the root filling had technical errors.

CBCT evaluation of root canal morphology and anatomical relationship of root of maxillary second premolar to maxillary sinus in a western Chinese population

BACKGROUND

To evaluate the root anatomy, root canal morphology and the anatomical relationship between the roots and maxillary sinus of maxillary second premolars by CBCT in a western Chinese population.

METHODS

A total of 1118 CBCT scans of the maxillary second premolars were collected from West China Hospital of Stomatology, Sichuan University. Information below were measured on axial, coronal and sagittal sections, recorded and evaluated properly: the number of roots and canals, the morphology of canal system classified by Vertucci standard, the inter-orifice distance of canal orifices, the curvature of each canal and the distance from root tip to maxillary sinus floor.

RESULTS

Among the 1118 teeth, 94.2% (1053) are single-rooted and 55.1% (616) have one canal. Type I (55.1%) is the commonest root canal morphology followed by Type II (31.9%). The mean inter-orifice distance (IOD) for multi-canal teeth ranging from 2.72 ± 0.32 to 3.41 ± 0.11 mm. Of 1622 canals, 38.8% (630) curvature are mesiodistal and 30.9% (501) are straight canals. The distance from root tip to maxillary sinus floor increased with age and the mean distance of single-rooted ones is 2.47 ± 3.45 mm.

CONCLUSIONS

All kinds of canal morphology category can be detected in maxillary second premolars. The IOD might be a predictable factor for root canal morphology. Roots of maxillary second premolars are related to maxillary sinus which should be treated carefully.

Assessment of Mesiobuccal Canal Configuration, Prevalence and Inter-Orifice Distance at Different Root Thirds of Maxillary First Molars: A CBCT Study

Aim

The aims of this study were to assess the prevalence and configuration of the second mesiobuccal (MB2) canal in the mesiobuccal MB root of permanent maxillary first molars at different root levels in a Saudi sub-population using cone‑beam computed tomography (CBCT) and to measure the inter-orifice distance between MB & MB2 at the pulpal floor level.

Materials and Methods

This retrospective study was carried out on CBCT images of Saudi patients seen at King Abdul Aziz University. A total of 106 maxillary first molars were evaluated using a specialized software program (iCAT CBCT software). The prevalence of MB2, canal configuration and location of joining (apical-middle-coronal), if present was calculated. Also, the inter-orifice distance between both canals was measured at the level of the pulpal floor. Chi‑square and one-way analysis of variance (ANOVA) were used.

Results

The MB2 canal was found in 92 (86.8%) maxillary first molar teeth. The MB and MB2 canals were joined in 61 (58%) cases, where the location of joining was 14 (23%), 17 (27%), and 31 (50%) in the coronal, middle, and apical third, respectively. The mean inter-orifice distance between both canals at the level of the pulpal floor was 2.52±0.76 mm.

Conclusion

The prevalence of MB2 canal in this Saudi sub-population was high. The prevalence decreased as the root canal approached the apical third. There was no correlation between the average distance and occurrence of canal joining. CBCT is useful in detecting and mapping the mesiobuccal root canal system, with a likelihood of enhancing the quality of root canal treatment.

Prevalence and risk factors of Apical periodontitis in endodontically treated teeth: cross-sectional study in an Adult Moroccan subpopulation

Background

The present study aimed at investigating the prevalence of Apical periodontitis in a Moroccan Adult subpopulation with a non-surgical root canal treatment and to assess associated risk factors including endodontic treatment quality, periodontal health status, coronal restoration cavity design and quality.

Methods

A total of 358 endodontically treated teeth were evaluated after more than 1-year period in a Moroccan subpopulation according to predetermined criteria. Studied parameters were assessed clinically and radiographically. The association between coronal restoration quality, cavity design, periodontal status, root canal filling quality, coronal restoration related features, presence or absence of the opposing dentition and the periapical status was determined. Data were analyzed using chi-square test, odds ratio and logistic regression.

Results

The present study revealed that gingival health, coronal restoration with CL II cavity design, and root canal filling quality influenced periapical status of endodontically treated teeth. Multivariate analysis showed that this association was statistically significant for gingival inflammation (95% CI 1.08–3.91, OR 2.05, p = 0.02), inadequate coronal restoration (95% CI 1.16–4.04, OR 2.16, p = 0.01), inadequate root canal filling length and homogeneity (95% CI 1.24–3.01, OR 1.93, P = 0.004), (95% CI 1.41–4.44, OR 2.50, p = 0.002) respectively.

Conclusions

The present study revealed that inadequate coronal restorations especially with large proximal margins (CL II cavity design) and gingival inflammation increased the risk of apical periodontitis in endodontically treated teeth. Prevalence of Apical periodontitis in the present study was 72.1%.

Missed canals in endodontically treated maxillary molars of a Brazilian subpopulation: prevalence and association with periapical lesion using cone-beam computed tomography

OBJECTIVES

To evaluate the prevalence of missed canals in endodontically treated maxillary molars through cone-beam computed tomography (CBCT) images and to verify their association with the presence of periapical lesions.

MATERIAL AND METHODS

Three oral radiologists evaluated 633 maxillary molars in CBCT exams regarding number of roots, number of root canals, number of missed canals, anatomic identification of missed canals, presence of periapical lesions, and root location of the periapical lesions. Data were statistically analyzed at a 5% significance level.

RESULTS

Descriptive statistical analysis showed that among 395 first molars, 218 had at least one missed canal, and 186 (46.5%) had a missed canal and periapical lesion simultaneously. Of these, 72.4% (134) of the missed canals were only mesiobuccal 2 (MB2). Among 238 s molars evaluated, 121 presented at least one missed canal, and 104 (43.6%) had a missed canal and periapical lesion simultaneously. Of these, 81.7% (85) of the missed canals were only MB2. The chi-squared test showed an association between the presence of missed canals and periapical lesions for 1st and 2nd maxillary molars. Teeth that presented a missed canal showed an odds ratio (OR) of 2.57 (p < 0.0001) of being associated with a periapical lesion. Missed canal occurrence was positively related to the number of root canals (z = 13.06, p < 0.0001), meaning when the number of root canals is higher, there is a higher probability of missed canal occurrence. According to the model calculated prediction, for a one-unit increase in the number of canals, the probability of missed canals increases by 4.22%.

CONCLUSIONS

It was concluded that MB2 was the most frequently missed canal, associated with the presence of periapical lesions in endodontically treated maxillary molars.

CLINICAL RELEVANCE

Professionals' negligence of anatomical root variations has been contributed to the high prevalence of missed canals, leading to failures in endodontic treatment. Their association with periapical lesion occurrence emphasizes the importance of correct detection and instrumentation of these canals.

Assessment of fractures in endodontically treated teeth restored with and without root canal posts using high-resolution cone beam computed tomography

Background

Root fractures are a diagnostic challenge for dentists in endodontic treatment. This study aimed to determine the relationship between the characteristics of tooth fractures and the presence of root canal posts in endodontically treated teeth using high-resolution cone beam computed tomography (CBCT).

Material and Methods

Fifty high-resolution CBCT scans of endodontically treated teeth with a diagnosis of fracture were obtained, of which 30 were from women and 20 were from men. These scans were acquired with three Veraviewepocs 3D units and one 3D Accuitomo 170 unit, with a 40 × 40-mm field of view and 125 μm voxel size. The variables assessed included the type of fracture, extent of fracture, type of retention, post length, cause of endodontic failure, location of the lesion, and time required to detect the fracture (difficulty score). For data analysis, the chi-squared test, Student’s t-test, and multiple linear regression (α <0.05) were used.

Results

No association was found between the type of fracture and type of retention or between the type of fracture and its extent (P>0.05). On the other hand, the type of fracture significantly influenced the time required for its detection. Additionally, the most difficult plane for detecting the fracture and the difficulty score were associated, with statistically significant results.

Conclusions

The type of fracture in endodontically treated teeth was not associated with the type of post used for restoration. All of the CBCT systems used to detect tooth fracture showed the same efficiency.

Key words:Cone-Beam CT, Tooth Fracture, Root Canal Post.

Perception of a modular 3D print model in undergraduate endodontic education

AIM

To evaluate a modular 3D print training dental model with embedded human teeth and electronic working length determination for undergraduate endodontic education.

METHODOLOGY

Cone-beam volume tomography data of a human skull were transferred into stereolithographic (STL) data, and a customizable modular 3D print model with individually removable sextants and teeth was generated for the use in commercially available phantom heads. Each of sixty-eight students performed a complete root canal treatment on an extracted human tooth. Working lengths were determined with electronic apex locators (EAL) and verified radiographically. Subsequently, an evaluation was carried out with regard to the difficulty of the working steps access cavity preparation, working length determination, root canal preparation/irrigation and canal filling, and these steps were compared to commonly used benchtop models. Additionally, the agreement of electronic and radiographic working length determination was assessed and analysed statistically with the chi-square test.

RESULTS

A total of 68 teeth (20 incisors, 26 premolars and 22 molars) with 127 root canals were treated. In total, 87% of the students considered the modular 3D print model considerably more demanding than the conventional benchtop model. Overall, 96% felt better prepared for the clinical situation, 92% felt markedly reduced stress levels during endodontic practice in the subsequent clinical courses, and 93% of the students suggested the model should be used in future preclinical endodontic training. The preradiographic use of EAL resulted in 85% of the cases having radiographically acceptable working length determination within 0-2 mm from the radiographic apex. Readings more than 2 mm from the apex or beyond were significantly more common in molars than in premolars and incisors (P < 0.05).

CONCLUSIONS

The vast majority of students rated the modular 3D print training model positively despite it being more demanding. They also recommended its use in preclinical teaching and training. The model allowed a more realistic simulation of the clinical situation with a simultaneous use of EALs and led to reduced stress levels in endodontic treatment in the subsequent clinical courses.

Accidental perforations during root canal treatment: an 8-year nationwide perspective on healthcare malpractice claims

OBJECTIVES

To assess occurrence and its variation over time of serious accidental perforations during endodontic treatment and the fate of perforated teeth by tooth type and characteristics of patients and dentists.

MATERIALS AND METHODS

Data, based on patient documents on healthcare malpractice claims, comprised all endodontic injuries (n = 970) verified by the Patient Insurance Centre in Finland in 2002-2006 and 2011-2013. Two specialists in endodontics scrutinized the documents. Accidental perforations were recorded by location (tooth type, chamber/canals) and dichotomized as avoidable (could have been avoided by following good clinical practice) or unavoidable (normal treatment-related risks). Fate of perforation cases was recorded as treatment discontinued, root canal(s) filled, or tooth extracted. Background information included patients' and dentists' sex and age and the service sector. Statistical evaluation used Chi-square tests.

RESULTS

Serious accidental perforations comprised 29% of all verified injuries. Most perforations were judged as avoidable: 93% in patients aged below 35 years, 87% when located in the pulp chamber or in molars (84%); 70% of all perforations and 75% of those in molars resulted in tooth extraction. The overall rate of serious accidental perforations was 17.6 cases per 100,000 endodontic patients per year.

CONCLUSIONS

The rate of serious accidental perforations increased over time. The majority was in molars and resulted in tooth extraction.

CLINICAL RELEVANCE

Accidental perforations comprise almost a third of serious injuries during root canal treatment. However, four of five perforations could be avoided by following good clinical practice. Therefore, training is needed before adopting new working equipment and methods.

The incidence of nickel-titanium endodontic hand file fractures: A 7-year retrospective study in a tertiary care hospital

Aim:

The present retrospective cross-sectional study aims to evaluate the incidence and factors associated with nickel-titanium hand file fractures in root canal-treated teeth in a tertiary care hospital of western India.

Methodology:

The diagnostic records of intraoral periapical (IOPA) radiographs were analyzed to check for file fractures in the root canal-treated teeth. As a part of standardized departmental protocol, Hand ProTaper Universal file system (Dentsply, India) was used for chemomechanical preparation for root canal treatment. The file fractures were analyzed with reference to age group, type of teeth, curvature of the canal, site of file fracture in the canal, length of file fracture, level of file fracture, distance of the file fracture from the apex, and obturation status of the file-fractured tooth. Chi-square test was applied to assess the significance difference between the tested groups.

Results:

A total of 19,810 IOPA X-rays were screened and 2728 root canal-treated teeth were found and of these 2728 cases, 109 file-fractured teeth were observed.

Conclusion:

The total incidence of file fractures was 3.9/100 root canal-treated cases, and mandibular molars with severely curved canals (>25°) had shown the maximum incidence of file fractures.

Fracture behavior of root-amputated teeth at different amount of periodontal support - a preliminary in vitro study

Background

The purpose of this study was to evaluate the effect of the amount of periodontal support on the fracture resistance of root-amputated maxillary molar teeth restored with either direct class. I. restorations or class II. mesio-occluso-distal (MOD) indirect overlay restorations with cuspal coverage.

Methods

Sixty sound maxillary first molars were collected and randomly divided into four groups. In Groups 1 and 2, MOD cavities were prepared and all cusps were reduced by 2 mm, whereas in Group 3 and 4, only a conservative Class I. cavity was prepared. Subsequently, root canal treatment was performed and the mesio-buccal roots were amputated. Groups 1 and 2 were restored with indirect composite overlay, while Groups 3 and 4 received direct composite fillings. After restoration, teeth were embedded as follows: Groups 1 and 3: normal bone level, Groups 2 and 4: furcation involvement. The specimens were submitted to static fracture resistance testing. Fracture thresholds and fracture patterns were measured and evaluated.

Results

Group 1 had the highest fracture resistance (2311,6 N) among the restored groups and showed statistically significant difference compared to Group 2 (p = 0.038) and Group 4 (p = 0.011). There was no statistically significant difference in terms of fracture resistance between the rest of the groups. In terms of the fracture patterns, Group 3 was characterized by the highest percentage (60%) of mostly favorable fractures, while the rest of the groups showed predominantly unfavorable ones.

Conclusions

The amount of periodontal support seems to influence the fracture resistance of root-amputated and restored maxillary molars.

Root canal configuration and its relation with endodontic technical errors in premolar teeth: a CBCT analysis

AIM

To evaluate the association between endodontic technical errors and the root canal configuration (RCC) of human premolars, as well as their relationship with periapical lesions through cone-beam computed tomography (CBCT) images.

METHODOLOGY

The sample consisted of CBCT scans belonging to 136 patients, totalling 152 root filled premolars (185 roots). CBCT images were evaluated by two oral radiologists. RCC was recorded according to Vertucci's classification, and the endodontic treatment quality was judged on the presence and type of technical endodontic errors (underfilling, overfilling, nonhomogeneous filling, nonfilled canal, fractured instruments, root deviation and absence of coronal restoration). In addition, the presence of periapical lesions associated with each RCC was recorded. Data were expressed by frequencies and percentages, and intraobserver agreement was calculated using the Kappa test.

RESULTS

The most common RCC was type I (71%), followed by type IV (15%), type II (8%), type V (3%), type VI (1%) and type III (1%). Types VII and VIII were not observed in the sample. Underfilling was the most frequent endodontic technical error for most RCCs, except for types IV, V and 'other', whose most frequent error was a nonfilled canal. The presence of technical errors was greater with an increase in the proportion of the periapical lesions. The intraobserver agreement was excellent.

CONCLUSIONS

There was an increase in the prevalence of endodontic technical errors and in the presence of periapical lesions as the anatomical complexity of the root canals increased. Underfilled and nonfilled canal were the most frequent endodontic technical errors.