Application of a new system for classifying root and canal anatomy in studies involving micro-computed tomography and cone beam computed tomography: Explanation and elaboration

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

INTRODUCTION

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

METHODS

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

RESULTS

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

CONCLUSIONS

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

Exploring Technological Progress in Three-Dimensional Imaging for Root Canal Treatments: A Systematic Review

INTRODUCTION AND AIMS

Root canal therapy is a crucial aspect of endodontic treatment aimed at preserving natural dentition. Over the years, advancements in three-dimensional (3D) technology have revolutionized diagnosis and treatment planning. Different 3D technologies are used in dental care, such as cone-beam computed tomography (CBCT), which ensures 3D slice visualization, root canal microanatomy, and dynamic navigation throughout the pulp cavity. By exploring the latest technological progress in this field, we seek to understand how these innovations are enhancing precision, efficiency, and patient outcomes, shedding light on the benefits and potential impact of 3D imaging in improving root canal procedures.

METHODS

Literature was searched from different databases, including PubMed, ScienceDirect, The Cochrane Library, Scopus, and Google Scholar. Inclusion criteria involved studies on 3D technology in root canal therapy with comparison groups, including RCTs and non-RCTs. Excluded studies lacked 3D imaging advancements, a control group, or were review articles or case studies. Quality assessment utilized QUIN for in vitro studies and ROBINS-I for non-RCTs to evaluate the studies' validity.

RESULTS

According to the PRISMA guidelines, among 5015 initial articles, 16 were included. CBCT was the most used 3D imaging technique for root imaging followed by micro-computed tomography (MCT) and limited CBCT (LCBCT) imaging methods. 2D radiographs and 2D histological methods and clearing techniques were the most common comparative modalities. Overall, 3D imaging streamlined dental treatment as clinicians could visualize much clearer and higher-quality images. Different resolutions and voxel sizes were applied to improve imaging quality.

CONCLUSION

Three-dimensional imaging, especially CBCT, improves root canal treatments by providing superior image quality. CBCT outperforms other techniques like MCT and LCBCT, enhancing clarity. Varying resolutions and voxel sizes optimize the effectiveness of 3D imaging in root canal therapy.

CLINICAL RELEVANCE

The advancements in 3D imaging technology, particularly CBCT, have significantly enhanced the diagnosis and treatment planning for root canal therapy. CBCT provides detailed insights into intricate root canal anatomy, improving diagnostic accuracy.

Nomogram to predict radicular grooves in maxillary lateral incisors in preoperative orthodontic population

OBJECTIVES

This study aimed to develop and validate a predictive nomogram for diagnosing radicular grooves (RG) in maxillary lateral incisors (MLIs), integrating demographic information, anatomical measurements, and Cone Beam Computed Tomography (CBCT) data to diagnose the RG in MLIs based on the clinical observation before resorting to the CBCT scan.

MATERIALS AND METHODS

A retrospective cohort of orthodontic patients from the School and Hospital of Stomatology, Wuhan University, was analyzed, including demographic characteristics, photographic anatomical assessments, and CBCT diagnoses. The cohort was divided into development and validation groups. Univariate and multivariate logistic regression analyses identified significant predictors of RG, which informed the development of a nomogram. This nomogram's performance was validated using receiver operating characteristic analysis.

RESULTS

The study included 381 patients (64.3% female) and evaluated 760 MLIs, with RG present in 26.25% of MLIs. The nomogram incorporated four significant anatomical predictors of RG presence, demonstrating substantial predictive efficacy with an area under the curve of 0.75 in the development cohort and 0.71 in the validation cohort.

CONCLUSIONS

A nomogram for the diagnosis of RG in MLIs was successfully developed. This tool offers a practical checklist of anatomical predictors to improve the diagnostic process in clinical practice.

CLINICAL RELEVANCE

The developed nomogram provides a novel, evidence-based tool to enhance the detection and treatment planning of MLIs with RG in diagnostic and therapeutic strategies.

Classifying the internal anatomy of anterior teeth in the Yemeni population using two systems: a retrospective CBCT study

A precursor for effective root canal treatment (RCT) is a complete understanding of the internal anatomy of teeth. In this study, the authors aimed to classify the root canal morphology of anterior teeth in the Yemeni population and identify gender-based variations among them. In addition, the symmetry among adjacent quadrants was also evaluated. Cone beam computed tomography (CBCT) scans of 2935 anterior teeth, 1502 maxillary, and 1433 mandibular were analyzed for root canal morphology and symmetry. Comparison between groups and among different genders was done using the Chi-square test. All the maxillary teeth were single-rooted and had a predominantly 1TN1 (Vertucci Type I) canal morphology. In addition to 1TN1, the presence of 1TN1-2-1 (Vertucci type III) and 1TN1-2-1-2-1 (not classified NC according to Vertucci) morphologies were noticed in the maxillary canines. Among the mandibular anteriors, the canal morphologies identified include 1TN1 in majority of the scans followed by 1TN2-1 (Vertucci II), 1TN1-2-1, 1TN1-2 (Vertucci V), 1TN1-2-1-2 (Vertucci VII) was seen only in incisors and newer canal types like 1TN2-1-2-1 (NC Vertucci) and 1TN1-2-1-2-1 (NC Vertucci) was seen in canines and lateral incisors. Two roots were only seen in the mandibular canines and classified as 2TN1-2 (NC Vertucci). Variations in root and root canal morphologies were seen among both genders. However, the results were not significant. All the maxillary teeth except 0.8% were bilaterally symmetrical. In mandible, symmetry ranged between 84.5 and 86.5%. In conclusion, single-rooted teeth with 1TN1 classification are most commonly seen in all the anterior teeth. Gender-based differences were non-significant, and bilateral symmetry was high. Ahmed et al. classification could precisely represent the root canal morphology in two rooted teeth.

Performance of obturation techniques in anatomical irregularities located at different thirds of the root canal system

This study aimed to compare the quality of root canal obturation (ratio of area occupied by gutta-percha (G), sealer (S), and presence of voids (V)) in different anatomical irregularities (intercanal communications, lateral irregularities, and accessory canals) located at different thirds of the root canal system of mandibular molar replicas. Sixty-seven 3D printed replicas of an accessed mandibular molar were prepared using ProGlider and ProTaper Gold rotatory systems. Three specimens were randomly selected to be used as controls and did not receive further treatment. The rest were randomly distributed in 4 experimental groups to be obturated using either cold lateral compaction (LC), continuous wave of condensation (CW), and core-carrier obturation (ThermafilPlus (TH) or GuttaCore (GC)) (n=16 per group). AHPlus® sealer was used in all groups. The three controls and a specimen from each experimental group were scanned using micro-computed tomography. The rest of the replicas were sectioned at the sites of anatomical irregularities and examined at 30× magnification. The G, S, and V ratios were calculated dividing the area occupied with each element by the total root canal area and then compared among groups using the Kruskal-Wallis test. Voids were present in all obturation techniques with ratios from 0.01 to 0.15. CW obtained a significantly higher G ratio in the irregularity located in the coronal third (0.882) than LC (0.681), TH (0.773), and GC (0.801) (p<0.05). TH and GC achieved significantly higher G ratios in those located in the apical third (p<0.05). The worst quality of obturation was observed in the loop accessory canal with all obturation techniques. Whitin the limitations of this study, it can be concluded that CW and core-carrier obturation are respectively the most effective techniques for obturating anatomical irregularities located in the coronal and the apical third.

Cone-Beam Computed Tomography for the Evaluation of Dental Pulp Chamber Volume: Implications for Clinics and Teaching

The dental pulp chamber volume is a fundamental measurement in the field of endodontics, but also in forensic sciences, teaching and training, or tissue engineering. This study evaluates the precision of cone-beam computed tomography (CBCT) in comparison with computed micro-tomography (micro-CT) in evaluating the pulp chamber volume of the upper central incisors ex vivo. The intra-operator and inter-operator errors were evaluated, and the results for the two techniques were compared with those of a T-test for paired samples. The intra-operator and inter-operator errors were >0.05, indicating adequate reproducibility in each operator and no significant differences between their measurements. On the other hand, no significant differences between the two measurement techniques were found. The present results demonstrate that CBCT is a precise, feasible, and reproducible technique for the evaluation of the dental pulp chamber volume ex vivo. The results provided with this method are useful for different medical domains but also for the teaching and training of undergraduate and postgraduate students. Furthermore, the findings of this study carry significant clinical implications, as the accurate assessment of the pulp chamber volume is critical in the diagnosis and treatment of various endodontic conditions. The ability of CBCT to provide reliable 3D dental anatomy measurements can enhance the planning of endodontic treatments by allowing for a better understanding of the internal tooth morphology. Additionally, the precision and reproducibility of CBCT in assessing the pulp chamber volume can contribute to improved clinical outcomes and reduced complications during endodontic procedures. These findings further support the increasingly vital role of CBCT in modern clinical practice and underscore its value as an indispensable tool in the field of dentistry.

Characterization of the root and canal anatomy of maxillary premolar teeth in an Iraqi subpopulation: a cone beam computed tomography study

This study aims to evaluate the number of roots and root canal morphology types of maxillary premolars in relation to a patient's gender and age in an Iraqi population using two classification systems. Cone beam computed tomography (CBCT) scans of 1116 maxillary premolars from 385 patients were evaluated for the number of roots and root canal morphology types according to Vertucci's classification and Ahmed et al. classification systems. Differences in the number of roots and root canal morphology types with regard to tooth type, patients' gender and age groups were evaluated and the degree of bilateral symmetry was determined. Chi-squared test was used for statistical analysis. About 51.1% of the 1st premolars were double rooted. The majority (87.9%) of the 2nd premolars were single rooted. The three-rooted form presented in only 1.2% and 0.7% of the 1st and 2nd premolars, respectively. Vertucci Type IV (Ahmed et al. code 2MaxP B1P1) and Vertucci Type I (Ahmed et al. code 1MaxP1) were the most common canal morphology types in the 1st and 2nd premolars, respectively. Females showed a lower number of roots and a higher prevalence of Vertucci Type I configuration (P < 0.05). Younger age groups showed a higher prevalence of Vertucci Type I configuration (P < 0.05). Bilateral symmetry was seen in more than half of the maxillary premolars. There is a considerable variation in the number of roots and root canal configurations of maxillary premolars in the studied Iraqi population, with a significant difference by gender and age groups. Ahmed et al. classification provided more accurate presentation of the root and canal anatomy in maxillary premolars compared to Vertucci's classification.

Expert consensus on difficulty assessment of endodontic therapy

Endodontic diseases are a kind of chronic infectious oral disease. Common endodontic treatment concepts are based on the removal of inflamed or necrotic pulp tissue and the replacement by gutta-percha. However, it is very essential for endodontic treatment to debride the root canal system and prevent the root canal system from bacterial reinfection after root canal therapy (RCT). Recent research, encompassing bacterial etiology and advanced imaging techniques, contributes to our understanding of the root canal system's anatomy intricacies and the technique sensitivity of RCT. Success in RCT hinges on factors like patients, infection severity, root canal anatomy, and treatment techniques. Therefore, improving disease management is a key issue to combat endodontic diseases and cure periapical lesions. The clinical difficulty assessment system of RCT is established based on patient conditions, tooth conditions, root canal configuration, and root canal needing retreatment, and emphasizes pre-treatment risk assessment for optimal outcomes. The findings suggest that the presence of risk factors may correlate with the challenge of achieving the high standard required for RCT. These insights contribute not only to improve education but also aid practitioners in treatment planning and referral decision-making within the field of endodontics.

Three-dimension model of root canal morphology of primary maxillary incisors by micro-computed tomography study

The success of root canal treatment for deciduous teeth depends upon the shape of the root canal, among other factors. Despite this, there are limited reports on the use of high-resolution micro-CT to describe the root canal morphology of primary maxillary incisors. In this study, we aimed to create a three-dimensional (3D) digital model of the root canal morphology of primary maxillary incisors using microcomputed tomography (micro-CT). To provide a reference for the development of restorative posts for the primary maxillary incisors. Primary maxillary central and lateral incisors (n = 10 each) were analysed. Micro-computed tomography was used to conduct 3D analyses of the root canal system of the primary maxillary incisors. The canal volume and surface area of the primary maxillary central incisors were larger than those of the primary maxillary lateral incisors. The structural model index value was significantly lower in central incisors. At the cervical level and the interface between the cervical and middle one-third cross-sectional levels, the root canals of the primary maxillary lateral incisors were significantly rounder. The labio-palatal dimension and the diameters of the central incisors at the four different levels were significantly smaller than the diameter of the mesio-distal dimension. The taper of the central and lateral incisors gradually increased from the apical one-third to the cervical one-third in the labio-palatal dimension. The data obtained from the 3D analysis of maxillary incisors in this study will contribute to the design of root canal posts.

A New Methodology to Determine the Orifice for Root Canal Configurations in First Permanent Molar Root and Canal Morphologies Using Micro-Computed Tomography

BACKGROUND

The distinction between where the pulp chamber ends and the root canal system begins is poorly defined within the existing literature.

METHODS

This paper aimed to describe a range of accurate methods to define the transition from pulp chamber to root canal in different first molar root morphologies using micro-focus computed tomography (micro-CT).

METHODS

The sample consisted of 86 mandibular and 101 maxillary first molars from the skeletal collections housed in the Department of Anatomy and Histology of the Sefako Makgatho Health Sciences University and the Pretoria Bone Collection. A stepwise approach using the cemento-enamel junction (CEJ) and dedicated landmarks was followed to create an automated cross-sectional slice.

RESULTS

Transition from pulp chamber to root canal could be accurately determined on maxillary and mandibular teeth. The occurrence of two separate roots in mandibular molars was 97.7%, with the remaining 2.3% having an additional disto-lingual root, with no mandibular molars displaying fused roots. In the maxillary molars, 92.1% had three separate roots and 7.9% displayed root fusion. Within this group, one tooth displayed a C-shaped root canal configuration and one a mesotaurodont-type morphology.

CONCLUSION

The suggested methodology to determine orifice location was found to be appropriate in all morphological types.

Critical analysis of a new system to classify root and canal morphology - A systematic review

A novel system to classify root and canal morphology was recently introduced (Ahmed et al. 2017). This systematic review aimed to answer the following research question: Does the Ahmed et al. system provide a more accurate and practical classification of root and canal anatomy compared to other classifications? A literature search was conducted in Google Scholar, Scopus and Wiley Online Library to identify the citation counts for the article entitled 'A new system for classifying root and root canal morphology; doi.org/10.1111/iej.12685'. After removal of duplicates and unrelated articles, 15 studies were included and analysed. All studies compared the Ahmed et al. system with the Vertucci classification. Results revealed that both systems were able to classify simple canal configurations in single-rooted anterior and premolar teeth, disto-buccal and palatal roots of maxillary molars. However, the Ahmed et al. system provided more accurate and comprehensive categorisations of single-rooted teeth with complex canal anatomy, multi-rooted maxillary and mandibular premolars and the mesio-buccal root of maxillary molars. Further evidence on the utility of the Ahmed et al. system is required using other diagnostic devices especially in molars.

Investigation of mandibular second molar root and canal morphology in a Black South African population using cone-beam computed tomography and two classification systems

PURPOSE

To investigate the root and canal morphology of mandibular second molars, including anatomical variations, in a Black South African population using two classification systems.

METHODS

Cone-beam computed tomography images of 386 teeth were evaluated. The number of roots and canal configurations were categorized using the classifications of Vertucci (with modifications by Sert and Bayirli) and Ahmed et al. (including the modified Melton classification). Relationships between variables were assessed using Fisher's exact test (P < 0.05).

RESULTS

Mandibular second molars were predominantly two-rooted (91.7%). The majority of teeth had three canals including Type IV mesial (41.2%) and Type I (75.1%) distal (Ahmed et al. configuration: 2MDM M2 D1). Three or more canals were present in almost one-fifth of mesial (n = 72/386, 18.6%) and a small number of distal (n = 21/386, 5.4%) roots. Males displayed additional canals more frequently in the distal root (P = 0.02). C-shaped anatomy was found in 5.7%. Among the C-shapes, the most common was Melton's Type III in the coronal (50%), middle (81%) and apical (72%) thirds.

CONCLUSION

In this population, mandibular second molar teeth exhibited diverse morphology, which would have clinical significance for endodontic practitioners. The Ahmed et al. classification provided a better description than the Vertucci classification.

Cone beam computed tomography analysis of the root and canal morphology of the maxillary second molars in a Hail province of the Saudi population

Background

The goal of the present research was to employ CBCT imaging to assess the root and canal anatomy of maxillary second molars in a population from the Hail province of Saudi. The effects of gender and side were taken into account.

Methods

The investigation included a sample size of 499 completely developed right and left untreated maxillary second molars obtained from 250 Saudi people. The root morphology of each tooth was evaluated. The examination also included an analysis of the canal morphology for each tooth, utilizing Vertucci's categorization. The effect of genders as well as sides was recorded. Results were analyzed using the Chi-square test.

Results

464 teeth had three roots (93.0%), whereas 20 teeth (4.0%) had two roots. One root was recorded in 7 (1.4%) of the study sample, whilst 8 (1.6%) had four roots. Although there were no significant differences between the left and right sides (p = .075), gender had a significant influence on the number of roots (p = .030). 240 M (48.1%) had three canal orifices, and 247 (49.5%) had four root canal orifices. Eight molars (1.6%) had two canal orifices, while one and five canal orifices were found in 3 (0.6%) and one (0.2%), respectively. Gender had a significant impact on the number of root canal orifices (p = .039). The observed differences in the orifices of the root canals between the left and right sides were not statistically significant (p = .059). The prevalence of MB2 in maxillary second molars was found to be 49.7%. In the mesiobuccal root, the Vertucci type I configuration had the highest canal frequency (50.3%), followed by the Vertucci types II (14.4%), IV (13.8%), V (12.0%), and III (7.6%), and VI (1.8%). The prevalence of Vertucci type I canal configurations was found to be higher in the distobuccal root (99.4%) and palatal root (98.2%) of maxillary second molars.

Conclusions

Significant variations in root canal anatomy were observed within the Saudi population. The majority of the subjects from Saudi Arabia in this study exhibited the presence of maxillary second molars with three roots. Approximately half of the sample under investigation exhibited the presence of the four canals.

Root and canal morphology of maxillary second molars in a Black South African subpopulation using cone-beam computed tomography and two classifications

This study investigated the root and canal morphology of maxillary second molars in a Black South African population using high-resolution cone-beam computed tomography. In total, 386 maxillary second molar teeth were evaluated and described according to the classifications of Vertucci (with the additions of Sert and Bayirli), as well as Ahmed et al. Root number, fusions and canal morphology were recorded. Relationships between morphology, sex and age were assessed using Fisher's exact test (p < 0.05). Maxillary second molars were predominantly three-rooted (96.1%), with root fusion observed in 14%. No relationships between sex, age and canal morphology were found. Additional canals were observed in 67.4% of mesiobuccal roots. The Ahmed et al. classification provided a better overall description of the morphology. In this population, maxillary second molar teeth exhibited a diversity of root and canal morphology. Complex variations may render endodontic management more difficult and increase the possibility of missed anatomy.

Challenges Assessment in Endodontics Among Undergraduate Students

Objective To explore perceptions of undergraduate dental students regarding difficulties faced during endodontic procedures. Methods An e-questionnaire was sent to 57 fourth-year and 45 fifth-year dental students. It comprised questions regarding demographic data and difficulties faced during different steps of the endodontic treatment. The responses were recorded on a 5-point Likert scale. During dichotomization, responses where one and two were chosen were considered yes whereas responses where three, four, and five were chosen were considered no. The sample size (SS) calculated using the Qualtrics SS calculator was 89. Data were analyzed using SPSS version 20. Frequencies and percentages were calculated. A p-value of less than 0.05 was considered significant. The chi-square test was applied for comparison based on the students' academic year and genders. Results Ninety students responded with an 88.2% response rate. Most students reported not facing any difficulty in differentiating healthy pulp and periapex from conditions of pulp pathosis (78.9%) and periapical pathosis (75.6%). Most males found access opening and de-roofing of the pulp chamber (35.6%) and working length determination (31.1%) difficult. Females reported having difficulty mostly in mesial and distal shift radiograph techniques (55.6%) and access openings (51.1%). No statistical difference was found based on an academic year or gender except in the use of mesial and distal shift techniques for radiograph acquisition Conclusion Assessing difficulties encountered by students during endodontic therapy can aid in the development of teaching strategies for preclinical and clinical instruction. Mesial and distal shift techniques, access cavity preparation, and working length determination are areas requiring more focus in the training process.

Evaluation of root and canal morphology of mandibular premolar amongst Saudi subpopulation using the new system of classification: a CBCT study

BACKGROUND

The clinician should have complete knowledge of the normal anatomy of the root as well as complexities in the root canal configuration for a better outcome, as missed or improper handling of the canal system can lead to the failure of an entire endodontic procedure. The present study aims to assess the morphology of roots and canals in permanent mandibular premolars in the Saudi subpopulation with a new classification system.

METHODS

The present study includes 1230 mandibular premolars (645 first premolars and 585-second premolars) from 500 CBCT images of the patients, including retrospective data. iCAT scanner system (Imaging Sciences International, Hatfield, PA, USA) was used to obtain the images; scanning of 8 × 8 cm images was performed at 120 KVp and 5-7 mA with a voxel size of 0.2 mm. The new method of classification presented by Ahmed et al. 2017 was used to record and classify the root canal morphology, followed by recording the differences regarding the age and gender of the patients. Comparison of canal morphology in lower permanent premolars and its association with gender and age of the patients was done by Chi-square test/ Fisher exact test; the significance level was set at 5% (p ≤ 0.05).

RESULTS

The left mandibular 1st and 2nd premolars with one root were 47.31%, with two roots were 2.19%. However, three roots (0.24%) and C-shaped canals (0.24%) were reported only in the left mandibular 2nd premolar. The right mandibular 1st and 2nd premolars with one root were 47.56%, with two roots were 2.03%. The overall percentage of the number of roots and canals in the first and second premolars ¹ PM ¹ (88.38%), ² PM ¹ B ¹ L ¹ (3.5%), ² PM B ¹ L ¹ (0.65%), ¹ PM ^1-2-1 (3.08%), ¹ PM ^1-2 (3.17%), ¹ PM ^1-2-1-2 (0.24%), ³ PMMB ¹ DB ¹ L¹ (0.48%). However, the C-shaped canals (0.40%) were reported in right and left mandibular second premolars. No statistically significant difference was reported between mandibular premolars and gender. A statistically significant difference was reported between mandibular premolars and the age of the study subjects.

CONCLUSION

Type I (¹ TN ¹) was the major root canal configuration in permanent mandibular premolars, which was higher among males. The CBCT imaging provides thorough details about the root canal morphology of lower premolars. These findings could support diagnosis, decision-making, and root canal treatment, for dental professionals.

Root and canal morphology of third molar teeth

Restorative and prosthetic considerations usually necessitates endodontic treatment of third molars in order to retain them as a functional component of the dental arch. However, the anatomy of third molars has been described as unpredictable. To date, there has been little published work on root and canal morphology of third molars, with an adequate sample size. The aim of this study was to investigate root and canal morphology of third molars. Maxillary and mandibular third molars were gathered from dental surgeries within north Jordan. Following access cavity preparation, pulp tissue was removed and root canals stained. Teeth were subject to examination after rendering them clear by immersion in methyl salicylate, and the following features evaluated: (1) number of roots; (2) number and type of root canals; (3) number and position of lateral canals; and (4) presence of inter-canal communications. Out of the examined 592 maxillary third molars, 69.9% had three roots, 10.81% had one, 9.79% had two, 9.12% had four, and 0.34% had five roots. Most had three (52.36%) and four canals (28.2%) with less frequency of two (11.48%), one (5.91%) and five canals (2.03%). Of the 639 mandibular third molars, 89.76% had two roots, 7.35% had three, 2.5% had one, and 0.47% had four roots. Most had three (55.71%) and two canals (29.42%) with less frequency of four (13.61%), one (1.09%) and five canals (0.15%). The majority of maxillary third molars had 3 roots, while the majority of mandibular third molars had two. Overall, nearly half of the maxillary and mandibular third molars had three canals. New canal configurations, not previously described in the literature nor included in Vertucci's classifications, were identified in both maxillary and mandibular third molars.

A study of mandibular premolar root and canal morphology in a Black South African population using cone-beam computed tomography and two classification systems

PURPOSE

An investigation of the configurations of mandibular premolar roots and canals in a population of Black South Africans.

METHODS

Cone-beam computed tomography analysis of 772 mandibular premolars was performed, and the premolars were classified according to the systems proposed by Vertucci and Ahmed et al. Root number, canal morphology, age, and sex were recorded. Fisher's exact test was used to determine relationships based on age and sex (P < 0.05).

RESULTS

Single roots were seen in the majority of mandibular premolars (97.1%). Single canal configurations (i.e., Vertucci Type 1/Ahmed et al. ¹MP¹) were observed in 48.5% of first and 81.3% of second mandibular premolars. Mandibular first premolars demonstrated multiple canals in more than half of the sample (51.5%), and C-shaped morphology in more than one-tenth (11.1%). A relationship between sex and the presence of radicular grooves was demonstrated (P = 0.049), males being more likely to demonstrate this feature (P = 0.051). Multiple canals in mandibular first premolars also showed a relationship with sex (P = 0.005), a male predilection being evident (P = 0.007). The Ahmed et al. system proved superior to the Vertucci classification for reporting complex configurations and anatomical variations, although a greater number of unique categories were created.

CONCLUSION

Diverse mandibular premolar root and canal morphology was observed in the studied population. Clinicians must be aware of common morphological features as well as possible anatomical variations in mandibular premolars, as failure to treat complete root canal systems may negatively impact endodontic treatment outcomes.

Impact of lattice versus solid structure of 3D-printed multiroot dental implants using Ti-6Al-4V: a preclinical pilot study

Purpose

Various studies have investigated 3-dimensional (3D)-printed implants using Ti-6Al-4V powder; however, multi-root 3D-printed implants have not been fully investigated. The purpose of this study was to explore the stability of multirooted 3D-printed implants with lattice and solid structures. The secondary outcomes were comparisons between the 2 types of 3D-printed implants in micro-computed tomographic and histological analyses.

Methods

Lattice- and solid-type 3D-printed implants for the left and right mandibular third premolars in beagle dogs were fabricated. Four implants in each group were placed immediately following tooth extraction. Implant stability measurement and periapical X-rays were performed every 2 weeks for 12 weeks. Peri-implant bone volume/tissue volume (BV/TV) and bone mineral density (BMD) were measured by micro-computed tomography. Bone-to-implant contact (BIC) and bone area fraction occupancy (BAFO) were measured in histomorphometric analyses.

Results

All 4 lattice-type 3D-printed implants survived. Three solid-type 3D-printed implants were removed before the planned sacrifice date due to implant mobility. A slight, gradual increase in implant stability values from implant surgery to 4 weeks after surgery was observed in the lattice-type 3D-printed implants. The marginal bone change of the surviving solid-type 3D-printed implant was approximately 5 mm, whereas the value was approximately 2 mm in the lattice-type 3D-printed implants. BV/TV and BMD in the lattice type 3D-printed implants were similar to those in the surviving solid-type implant. However, BIC and BAFO were lower in the surviving solid-type 3D-printed implant than in the lattice-type 3D-printed implants.

Conclusions

Within the limits of this preclinical study, 3D-printed implants of double-rooted teeth showed high primary stability. However, 3D-printed implants with interlocking structures such as lattices might provide high secondary stability and successful osseointegration.

Effectiveness of antimicrobial photodynamic therapy as an adjunct to mechanical instrumentation in reducing counts of Enterococcus faecalis and Candida albicans from C-shaped root canals

BACKGROUND/PURPOSE

The aim was to assess the effectiveness of antimicrobial photodynamic therapy (aPDT) as an adjunct to mechanical instrumentation (MI) in reducing Enterococcus faecalis (E faecalis) and Candida albicans (C albicans) counts from C-shaped root-canals.

METHODS

Teeth with C-shaped canals as identified on cone beam computed tomographic images were included. Following incubation with E faecalis and C albicans, samples were divided into 4 groups a four follows: Group-1: MI with adjunct aPDT; Group-2: aPDT alone; Group-3: MI alone; and Group-4: no treatment. The pulp chambers of these teeth were exposed and coronal pulp was mechanically derided using sterile endodontic excavators. Using flexible files, all canals were debrided up to size #30 K-files with intermittent irrigation with 2.5% sodium hypochlorite irrigation. In Groups 1 and 3, methylene-blue was injected in all canals and aPDT was performed using a 600 nm diode laser. Sample-size estimation was done on data from a pilot investigation and group-comparisons were done using one way analysis of variance and Bonferroni post-hoc adjustment tests. P < .05 was considered statistically significant.

RESULTS

Sixty periodontally hopeless mandibular second molars with C-shaped canals were included. There was a statistically significant reduction CFU/mL of E faecalis (P < .001) and C albicans (P < .001). At post-operative microbial assessments in Group-1. There was no difference CFU/mL of E faecalis and C albicans at post-operative microbial assessments in Groups 2-4.

CONCLUSION

MI with adjunct aPDT is more effective in reducing count of E faecalis and C albicans from C-shaped root canals.

Micro-computed tomography analysis of root canal morphology and thickness of crown and root of mandibular incisors in Chinese population

OBJECTIVES

The aim of this study was to investigate the root canal morphology and the thickness of crown and root of mandibular incisors in a Chinese subpopulation by micro-computed tomography (micro-CT).

METHODS

In total, 208 mandibular incisors were scanned using micro-CT. The anatomical features of the canals (canal configuration, apical constriction, foramen-to-apex distance, accessory canal vertical distribution, and canal geometrical parameters) and the thickness of the crown and root 2/3 were evaluated.

RESULTS

Three canal categories, labeled as Single (77.88%), Merged (15.87%), and Separated (6.25%), were summarized. The most frequent constriction type in main foramina was single constriction (42.53%). Wide and narrow diameters in a single main foramen were 0.37 ± 0.14 mm and 0.26 ± 0.07 mm, respectively. The distance from the anatomical foramen to the physiological foramen and the anatomical apex was 0.49 ± 0.20 mm and 0.36 ± 0.28 mm, respectively. During the virtual root-end resection, 97.12% of roots underwent successful resection at the 2-mm level, with the foramina visible on the resection surface. During 2-D cross-sectional analyses, the shape parameters of the root and canal showed significant positive correlation (P < 0.05). The thickest and thinnest walls were the incisal and proximal walls (P < 0.05) of the crown, respectively. The buccal walls were significantly thicker than the lingual walls on the crown (P < 0.05), whereas the lingual walls were thicker on the root 2/3 (P < 0.05).

CONCLUSIONS

This study provides detailed information about the root canal morphology and thickness of the crown and root of mandibular incisors in a Chinese population. An understanding of morphology can benefit endodontic treatment.

CLINICAL RELEVANCE

Adequate knowledge of the crown, root, and canal morphology, as well as the thickness distribution of the crown and root, is essential for successful root canal therapy and prevention of complications.

Synergistic Effect of Plant Extracts on Endodontic Pathogens Isolated from Teeth with Root Canal Treatment Failure: An In Vitro Study

BACKGROUND AND OBJECTIVES

This study aimed to evaluate the synergistic antimicrobial activity of extracts obtained from Salvadora persica (Miswak), Commiphora molmol (myrrh) and Azadirachta indica (neem) in combination with commercially available antimicrobial agents: penicillin, tetracycline, ofloxacin and fluconazole on endodontic pathogens such as Enterococcus faecalis, Streptococcus mitis,Actinomyces naeslundii and Candida albicans.

MATERIALS AND METHODS

Microbiological samples from the root canals of the teeth undergoing retreatment were taken using sterile paper points kept at full length in the canal for 30 s. The disc diffusion method was used to check the susceptibility of microbes to the plant extracts and antimicrobials by measuring the diameter of the inhibition zones. Against the microbes, minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC)/minimum fungicidal concentration (MFC) of the plant extracts were assessed. The fractional inhibitory concentration index (FICI) was used to estimate the synergistic effect of plant extracts combined with antimicrobials against the resistant endodontic microbes.

RESULTS

The findings clearly indicate the effectiveness of all the three plant extracts, Commiphora molmol, Azadirachta indica, Salvadora persica, against all the experimental pathogenic microorganisms except for the ineffectiveness of Azadirachta indica, Salvadora persica against Candidaalbicans. Maximum antimicrobial activity was displayed by Azadirachta indica against Enterococcusfaecalis (MIC = 0.09 ± 1.2 mg/mL, MBC = 0.78 ± 1.25 mg/mL) and the minimum antimicrobial activity was displayed by Commiphora molmol against Actinomyces naeslundii (MIC = 12.5 ± 3.25 mg/mL, MBC = 100 ± 3.75 mg/mL). The best synergy was displayed by Commiphora molmol with fluconazole against Candidaalbicans (FICI = 0.45).

CONCLUSIONS

The current study delineates the variable antimicrobial activity of plant extracts against the experimental endodontic pathogenic microorganisms. Plant extracts in conjunction with various antimicrobials can be valuable aids in combating relatively resistant endodontic microorganisms that have been the cause of worry in recent years, leading to failure even in treatment procedures following all required protocols.