Three-dimensional modeling and measurements of root canal anatomy in second primary mandibular molars: a case series micro CT study

Root canal conicity determination of primary second molars using nanotomography: An in vitro study

BACKGROUND

The conicity of the root canals of primary teeth is an important measure for endodontic therapies. However, determining this conicity depends on the methods employed, which requires further investigation.

AIM

The aim of this study was to determine the conicity of the root canals of the upper and lower primary second molars using nanotomography (nCT).

DESIGN

An in vitro study was performed using nine primary second molars, both upper and lower, subjected to nCT. Comparisons between the diameters of root canals were performed between the thirds (cervical-D0, middle-D5, and apical-D7). The conicity (%) was determined for each root canal from cervical to apical. Data were statistically analyzed with a significance level of 5%.

RESULTS

The conicity ranged from 2% to 8% for the upper primary second molars. Significant differences in root canal diameter between the thirds (D0, D5, and D7 points) were observed in the mesio- and distobuccal roots (p < .05), but not in the palatal roots (p > .05). For the lower primary second molars, the conicity ranged from 2% to 17%, as well as significant differences in root canal diameter between the thirds (D0, D5, and D7 points) were observed in all roots (distal, mesiobuccal, and mesiolingual; p < .05).

CONCLUSION

The conicity of the upper primary second molars was different from that of the lower ones, which showed a greater variability.

Cone-beam computed tomography assessment of the root canal morphology of primary molars

BACKGROUND

This study aimed to assess the root canal morphology of primary molars using cone-beam computed tomography (CBCT).

METHODS

This cross-sectional study evaluated 60 maxillary and mandibular primary first and second molars on CBCT scans of patients retrieved from the archives of Hamadan School of Dentistry between 2018-2020. The teeth were evaluated regarding the number of roots and canals, canal type according to the Vertucci's classification, and root surface concavities. Data were analyzed descriptively and by independent t-test.

RESULTS

The most frequent number of canals and roots in the maxillary right and left first molars was 3 canals (60%) and 3 roots (80%). These values were 4 canals (80%) and 5 canals (50%) with 3 roots in the maxillary right and left second molars, respectively, 4 canals (100%) and 2 roots (50%), and 3 canals (60%) and 2 roots (50%) in mandibular right and left first molars, respectively, and 4 canals (92.3%) and 3 roots (61.5%) in mandibular right and left second molars. Vertucci's type IV was the most common canal type in mesial and distal canals, type I was the most common in mesiobuccal, mesiolingual, distobuccal, and distolingual, and types I and II were the most common in the palatal canal. The maximum and minimum concavities were noted in the buccal (26.7%) and mesial (8.3%) surfaces, respectively.

CONCLUSIONS

A wide variation exists in the number of roots and canals of maxillary and mandibular primary molars, which calls for further attention in treatment of such teeth.

The Contribution of Various In Vitro Methodologies to Comprehending the Filling Ability of Root Canal Pastes in Primary Teeth

A void-free obturation during root canal treatment on primary teeth is currently very difficult to attain. In this study, the pulpectomy filling abilities of Bio-C Pulpecto (Angelus, Basil, Londrina, Paraná, Brazil) and of zinc oxide eugenol, or "ZOE" (DenPro, Prevest, New York, NY, USA), were compared using several in vitro techniques. Therefore, 30 primary anterior teeth were used in the present in vitro study. Analysis of variance (ANOVA), including a multiple comparison procedure (Holm-Sidak method, Dunn's Method, or Tukey test), was used. On micro-CT, Bio-C Pulpecto exhibited higher void percentages than did ZOE (10.3 ± 3.8%, and 3.5 ± 1.3%), respectively (p < 0.05). With digital microscopy, higher total void percentages were found in the BC (13.2 ± 26.7%) group compared to the ZOE (2.7 ± 2.8%) group (p < 0.05). With the CLSM, mean tubular penetration depths were higher for Bio-C Pulpecto than for ZOE in all canal thirds (p < 0.05). SEM images demonstrated no tags into dentinal tubules in either group throughout the three thirds. Moreover, higher statistically significant flowability was found for Bio-C (2.657 ± 0.06 mm) compared to ZOE (1.8 ± 0.13 mm) (p < 0.05). The findings of this study indicate that neither ZOE nor Bio-C Pulpecto appears to meet the criteria for an ideal root canal filling paste for primary teeth. This study laid the groundwork for future research by determining how micro-CT, digital microscopy, SEM, and CLSM contribute to our understanding of the filling process of primary teeth. More thorough research on the mechanism of root canal obturation on primary teeth is required to achieve a long-term successful root canal therapy in young children.

The Effectiveness of Different Irrigation Techniques on Debris and Smear Layer Removal in Primary Mandibular Second Molars: An In Vitro Study

AIMS

The aim of the present in vitro study was to compare the effectiveness of passive ultrasonic irrigation (PUI), sonic irrigation, and mechanic dynamic activation on the removal of debris and smear layer from primary mandibular second molars during pulpectomy.

MATERIALS AND METHODS

Mesial roots of 48 primary mandibular second molars were prepared with an R-motion 21 mm file (30/0.04) (FKG Dentaire SA, La Chaux-de-Fonds, Switzerland), irrigated with 1% sodium hypochlorite (NaOCl) and 17% ethylenediaminetetraacetic acid (EDTA), and divided into four groups (n = 24 canals) according to the final irrigation activation technique: control group without activation, PUI with Ultra-X (Eighteeth, Changzhou, China), mechanical activation with XP-endo Finisher (FKG), and sonic irrigation with EQ-S (Meta Biomed, Chungcheongbuk-do, Korea). The roots were split longitudinally and analyzed using scanning electron microscopy (SEM). The presence of debris and smear layer was assessed using a 5-grade scoring scale with 200× and 1000× magnification, respectively. The Kruskal-Wallis and Friedman tests were used for data analysis.

RESULTS

The activation of the irrigant significantly improved debris and smear layer removal (p < 0.001). There was no significant difference between Ultra-X, XP-endo Finisher, and EQ-S (p > 0.05). No activation technique was able to completely eliminate debris and smear layer from the root canals of primary mandibular second molars.

CONCLUSIONS

During pediatric pulpectomy, the irrigation protocol must include activation of the irrigation solutions using either ultrasonic, sonic, or mechanical activation techniques to enhance the removal of debris and smear layer for a better prognosis.

CLINICAL SIGNIFICANCE

During root canal treatment on primary teeth, the clinician must incorporate an activation technique in the irrigation protocol to enhance the removal of debris and smear layer and increase the success of the treatment.

Physicochemical and Antibacterial Properties of Conventional and Two Premixed Root Canal Filling Materials in Primary Teeth

In this study, some physicochemical and antibacterial properties of three root canal filling materials for primary teeth, Calplus “CP” (Prevest DenPro, Lewes, DE, USA), Bio-C Pulpecto “Bio-CP” (Angelus, Basil, Londrina, Paraná, Brazil), and Zinc Oxide and Eugenol “ZOE” (Prevest DenPro, Lewes, DE, USA) were compared. For each material, the pH, solubility, contact angle, and crystalline microstructure under SEM were evaluated. Their antibacterial activity against Enterococcus faecalis was determined through direct tests. The Kruskal−Wallis test was used to analyze the results using a one-way analysis of variance on ranks. All the materials had an alkaline pH at 3, 24, and 72 h, with CalPlus having the highest (p < 0.05). Bio-CP was more soluble during the evaluation period (24 h) than ZOE and CalPlus (p < 0.05). Bio-CP and ZOE demonstrated the creation of crystallite structures on their surfaces after immersion in PBS at 37 °C, whereas CalPlus showed none. The lowest contact angle was observed for Bio-CP (53 ± 1.5°); contact angles of (86 ± 4°) and (96 ± 1°), respectively, were observed after 10 s of the deposition of the water drop for CalPlus and ZOE. In conclusion, according to this study, there is still a need to develop new filling materials for primary teeth. ZOE, CalPlus and Bio-CP demonstrated different physicochemical and antibacterial properties, but none of the materials had optimal properties and could be considered the most suitable filling material for primary teeth pulpectomy. Bioceramics in their current state are not an alternative. The physicochemical and antibacterial properties still need improvement to fit the intricate anatomy of primary teeth.

Are electronic apex locators accurate in determining working length in primary teeth pulpectomies? A systematic review and meta-analysis of clinical studies

BACKGROUND

The lack of a well-defined apical constriction in primary teeth raises concerns regarding the accuracy of electronic apex locators (EALs) for measuring working length.

OBJECTIVES

To evaluate the accuracy of EALs in determining working length in primary teeth pulpectomies.

METHODS

Two reviewers searched ten databases up to September 2021. Clinical studies evaluating the accuracy of the electronic measurement of working length in primary teeth pulpectomies were included. Studies without a comparison group, with samples smaller than ten root canals, and that did not use a multiple frequency EAL were excluded. A meta-analysis was conducted to assess the paired differences in mean lengths between measurements obtained by electronic and comparative methods. In addition, a meta-analysis of proportion was applied according to the level of difference between the measures. The risk of bias and applicability of the studies were assessed using the QUADAS-2 tool. The certainty of evidence was assessed with the Grading of Recommendations, Assessment, Development and Evaluation (GRADE) approach.

RESULTS

Twenty-nine studies were included in the qualitative analysis and twenty-three in the quantitative analysis. The methods of comparison for the electronic measurement were the radiographic method, radiovisiographic, scanning electron microscopy, and direct visualization. The meta-analysis showed that the electronic measurement tends to be shorter than radiographic measurement, while the other methods showed no difference. The proportion analysis showed a higher pooled proportion of difference values between electronic and comparative measurements within -0.5 to +0.5 mm (69.31%). The certainty of the evidence suggested very low confidence in estimating the outcome.

DISCUSSION

The results of this review denote a good performance of the EALs in determining working length in primary teeth pulpectomies. However, these results are based on clinical studies with low methodological quality and high heterogeneity, which require careful interpretation for clinical practice.

CONCLUSIONS

Although the results suggest acceptable accuracy of EALs in determining working length in primary teeth pulpectomies, the low quality of the included studies and the very low certainty of the evidence require clinicians to interpret these results with caution. More robust evidence is required to support that these devices are accurate for primary teeth.

Root and Root Canal Anatomy of Primary Mandibular Central Incisor, Lateral Incisor, and Canine in Indian Children: A Cone Beam Computed Tomography Study

Background. A thorough knowledge of root and root canal morphology in primary dentition is essential for success of endodontic therapy. This information also finds importance in anthropological research in reconstructing human population history. Lack of studies of root and root canal morphology in mandibular anterior teeth prompted us to the present study. Methods. A total of 109 extracted primary mandibular incisors and canines were collected, out of which 90 teeth were selected for this study and divided into 3 groups: CI, mandibular central incisor; LI, mandibular lateral incisor; C, mandibular canine. All the sample teeth were scanned using cone beam computed tomography (CBCT). Number of roots, number of root canals, length of root, mesiodistal (MD), and buccolingual (BL) width of canal, shape of canal, and presence of accessory canals were assessed. Collected data were statistically compared using one-way ANOVA and chi-square tests. Results. All teeth studied displayed single root with single root canal conforming to type I Vertucci’s classification. Root length of CI was significantly shorter than both LI and C, with no significant difference between LI and C. Straight root canals were more common in CI and LI, whereas curved canals were more common in C. S-shaped canals were seen in a few CI and C. BL canal width was more than MD width in all teeth, C showing significantly larger dimensions than both CI and LI. Conclusion. This study presents root and root canal characteristics of primary mandibular central incisor, lateral incisor, and canine in children from Indian ethnicity.

Prevalence of Three-Rooted Deciduous Mandibular Molars in the Children of Northwestern Iran

Introduction

Although primary teeth have a determinative role in development of normal occlusion, few studies about anomalies related to deciduous dentition have been conducted so far. Regarding recent improvements in common knowledge and the importance of maintaining primary teeth until eruption of succedaneous teeth, identifying the morphology of primary teeth and probable variations is of great importance to achieve optimal therapeutic outcome. This study aims to determine the prevalence of three-rooted mandibular primary molars in a population of northwestern Iran.

Materials and Methods

In this descriptive cross-sectional study, periapical radiographs of patients attending private oral and maxillofacial radiology offices in the northwestern region of Iran from 2017 to 2019 were retrospectively reviewed. A total of 300 cases in the 3-10-year age range having bilateral periapical radiographs from mandibular primary molars were screened. First and second primary molars were observed meticulously. Gender, side of the mandible (right or left), symmetry, overall prevalence, and prevalence considering the type of molar (D or E) were recorded and analyzed.

Results

Overall prevalence of three-rooted mandibular primary molars was 9.33% ( 28/300), 92.9% of which were unilateral. The prevalence of teeth showing supernumerary roots among all teeth examined was 2.5% (30/1200). Considering symmetry and gender, the occurrence of these three-rooted primary molars did not differ significantly (respectively, p=0.832 and p=0.541). However, there was a significant relationship between the occurrence of supernumerary roots and left side for three-rooted first molars and right side for three-rooted second molars (p=0.021).

Conclusion

Obtained data show that three-rooted mandibular primary molars in children of northwest region of Iran have a prevalence of approximately 10 % which urges some specific considerations in exodontic and endodontic procedures.

Comparison of Various Root Canal Filling Materials and Obturation Techniques for Primary Teeth Using Microcomputed Tomography

Aim:

The aim of this study was to compare the effectiveness of different filling materials and obturation techniques for root canal obturation in primary teeth.

Materials and Methods:

Eighty maxillary primary incisors were included in this in vitro study. After biomechanical preparation, all samples were scanned using microcomputed tomography (micro-CT) and root canal volumes were calculated. Samples were grouped according to filling materials and obturation techniques, with ten samples in each group. The samples were filled with zinc oxide eugenol (ZOE) and Vitapex using four different obturation techniques (local anesthesia syringe, lentulo spiral, pastinject, and lentulo spiral–ultrasonic activation). After filling, samples were scanned a second time using micro-CT and root canal volumes were calculated. The statistical analysis was performed using SPSS version 24.0. Data were analyzed by Kruskal–Wallis and Mann–Whitney U tests.

Results:

When the ZOE and Vitapex were compared, it was observed that there were no significant differences between their postobturated volumes, percentage obturated volume (POV), internal void (IV), and percentage of internal void volume (PIV) ( P > .05). The local anesthesia syringe group had a significantly lower postobturated volume and POV, and a significantly higher IV and PIV for both filling materials than that by the other groups ( P < .05). There was no significant difference between the other obturation techniques ( P > .05). For the local anesthesia syringe group, postobturated volume and POV were significantly higher and IV and PIV were significantly lower with Vitapex than with ZOE ( P < .05). There was no significant difference between the other obturation techniques filled either with ZOE or Vitapex ( P > .05).

Conclusion:

Except for the syringe technique, no difference was observed between the ZOE and Vitapex materials. The syringe technique used in the primary root canal filling was less effective than the other techniques, which had similar efficacy, and in this technique, more effective canal filling was achieved with Vitapex.

Root canal instrumentation efficacy of non-fused and fused primary molar roots: a micro-computed tomography study

PURPOSE

Pulpectomy may be indicated in restorable primary teeth exhibiting irreversible pulpitis or pulpal necrosis. The purpose of this study was to compare the cleaning and shaping efficacy of NiTi systems (Reciproc^® Blue and MTwo^®) with manual stainless-steel instrumentation in primary molars using micro-CT analysis.

METHODS

Fifty-seven maxillary second primary molars were scanned using micro-CT. Teeth with three divergent roots were divided randomly (n = 15) according to instrument type (K file, MTwo®, and Reciproc® Blue). Teeth with root fusion were instrumented manually as a separate group (n = 12). Pre- and post-instrumentation micro-CT images were superimposed, and the instrumentation area (IA) and procedural complications were recorded.

RESULTS

No statistically significant differences in IA between file systems was observed in the non-fused teeth. The mean IA of fused roots was significantly lower than in the non-fused distobuccal (p = 0.003) and palatal (p < 0.001) roots. The root segment had a significant effect on IA (p < 0.001) and the highest mean IA was observed in the apical third. Manual instrumentation had fewer procedural complications compared with rotary systems.

CONCLUSION

No differences were determined in the cleaning and shaping effectiveness of all systems in non-fused teeth. Uninstrumented areas (> 60%) occurred in both non-fused and fused primary teeth with fewer procedural complications observed after manual instrumentation.

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

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.

For pulp treatment in primary teeth, rotary canal instrumentation may be modestly time efficient, but otherwise similar to manual canal instrumentation

ARTICLE TITLE AND BIBLIOGRAPHIC INFORMATION

A systematic review and meta-analysis of randomized clinical trials comparing rotary canal instrumentation techniques with manual instrumentation techniques in primary teeth. Manchanda S, Sardana D, Yiu CKY. Int Endod J. 2020;53(3):333-353.

SOURCE OF FUNDING

Information not available.

TYPE OF STUDY/DESIGN

Systematic review with meta-analysis of data.

Application of Computed Tomography Imaging in Diagnosis of Endocrine Nerve of Gastric Cancer and Nursing Intervention Effect

In this article, some parameters and characteristics of computed tomography (CT) images in patients with gastric cancer are analyzed and the application of CT images in the diagnosis of gastric cancer endocrine nerves and the impact of nursing intervention on the quality and mental state of CT images of patients with gastric cancer are discussed. First, all patients were scanned with CT, and the CT values of the normal stomach wall and all lesions at different single-energy levels were recorded separately. Second, the improved back propagation network model was applied to realize the diagnosis of gastric cancer through the analysis of various features of CT images. The effect of nursing intervention on the image quality and mental state of CT imaging of patients with gastric cancer was studied. The results show that the energy spectrum curve of CT images and the improved back propagation network model are helpful for the initial diagnosis and identification of gastric cancer. Nursing intervention has a good influence on the clinical examination, image diagnosis, and psychological state of patients with gastric cancer, and it is easy for patients to undergo image diagnosis and examination according to correct operating procedures.

A micro-computed tomographic assessment of root canal preparation with conventional and different rotary files in primary teeth and young permanent teeth

BACKGROUND

Root canals of primary teeth are commonly prepared with endodontic files that are originally manufactured for permanent teeth.

AIM

This micro-computed tomography (micro-CT) study evaluated and compared the changes in root canal morphology after preparation with different conventional and rotary files in primary teeth and young permanent teeth.

DESIGN

Seventy-two extracted primary and permanent molars were selected and randomly assigned to three subgroups according to the file systems used (n = 12/each). After pre-scanning of teeth with micro-CT, root canals were prepared with One Shape and Revo-S rotary systems and conventional endodontic files. After rescanning procedure, changes in canal volume, surface area, uninstrumented surface area, and apical transportation were evaluated. Mann-Whitney U test, Kruskal-Wallis test, and Conover's multiple comparison test were used for statistical analysis (P = .05).

RESULTS

Instrumentation with rotary files resulted in significantly greater volume and surface area of root canals and less uninstrumented areas (P < .001) than with manual files (P < .001). Primary molars showed significantly less apical transportation than permanent teeth (P < .001).

CONCLUSIONS

Preparation of canals with rotary files could be a viable alternative to conventional files in primary teeth. Regardless of the file system used, uninstrumented areas still exist in both primary teeth and permanent teeth.