Incidence of missed canals during endodontic treatment of maxillary first and second molars.

Untreated canals are a primary cause of persistent apical periodontitis, and the inability to identify and adequately treat canals has been considered a major cause of failure of root canal therapy in maxillary molars. The purpose of this retrospective study was to use cone beam computed tomography (CBCT) to quantify the number of missed canals in maxillary first and second molars needing endodontic retreatment after treatment by general dentists. A total of 401 CBCT scans of maxillary first and second molars were examined. A total of 214 scan sets (53.37% [95% CI, 48.48%-58.25%]) showed evidence of an untreated canal, with the highest rate (49.38%; n = 198) observed in the second mesiobuccal canal. Imaging revealed that multiple canals were missed in some patients, for a total of 225 missed canals. The examinations showed untreated first mesiobuccal canals in 2.99% of CBCT scan sets (n = 12), untreated distobuccal canals in 2.99% of CBCT scan sets (n = 12), and untreated palatal canals in 0.75% of CBCT scan sets (n = 3). Preoperative CBCT imaging should be considered prior to initial root canal treatment of maxillary molars. When the risks and limitations of CBCT are taken into consideration, the additional information it provides can improve diagnostic accuracy, increase confidence in decision-making, and positively impact treatment planning.

Analysis of morphology and symmetry of the root canal system of incisors, premolars and mandibular molars using CBCT.

Knowledge of root canal internal anatomy and its variations is important forproper endodontic treatment. It is therefore necessary to investigate morphological aspects among different dental groups in the same patient to define the best protocol for the case. AIM: To evaluate the morphology and symmetry of homologous incisors, premolars and mandibular molars using cone beam computed tomography (CBCT). MATERIALS AND METHOD: Descriptive statistical analysis was performed for the frequency of categorical variables, and a chi-square test or Fisher 's exact test was used to test whether gender and side were associated with number of roots, number of canals, and Vertucci's classification. Forty-five CBCT scans were evaluated, and 444 mandibular teeth were analyzed. The number of roots, number of canals, classification of the canals in each root according to Vertucci and presence of a symmetrical relationship between pairs of posterior teeth were analyzed. RESULTS: The resuls showed that 74% of mandibular central incisors had type I root canal, 26% of mandibular lateral incisors had type I and, with a significant difference in the number of canals between males and females (p < 0.05). In mandibular first premolars, 70.5% had type I; and in mandibular second premolars, 98.5% had type I. Mandibular first molars had two roots in 98% of the cases. Second mandibular molars had two roots in 92.5% of the cases, one root in 6%, and three roots in 1.5%. Symmetry between central incisors was higher in females than in males. CONCLUSIÓN: Teeth of the same group can have different morphologies in the same patient.

0 conhecimento da anatomia interna e suas variagoes anatómicas é fator importante para o adequado tratamento endodóntico. Portanto, é necessário investigar esses aspectos morfológicos entre diferentes grupos dentários de um mesmo paciente para definir o melhor protocolo para o caso. OBJETIVO: Avaliar a morfologia e simetria de incisivos, pré-molares e molares inferiores homólogos por meio de tomografia computadorizada de feixe cónico (TCFC). MATERIAIS E MÉTODO: Foi realizada análise estatística descri-tiva para a frequéncia das variáveis categóricas e foi utilizado o teste do qui-quadrado ou teste exato de Fisher para testar a relagao entre sexo e lado em comparagao com número de raízes, número de canais e classificagao de Vertucci. Quarenta e cinco TCFC foram avaliadas e 444 dentes inferiores foram analisados. Foram considerados: o número de raízes, o número de canais, o tipo dos canais acordo com a classificagao de Vertucci e a presenga de relagao simétrica entre pares de dentes posteriores. RESULTADOS: Os resultados mostraram que 74% dos incisivos centrais inferiores tinham um canal radicular tipo 1 e 26% tinham dois canais; 73% dos incisivos laterais inferiores, 26%oeram do tipo I, tinham um canal e 27% tinham dois canais, com diferenga significativa no número de canais entre os grupos masculino e feminino (p < 0,05). Nos primeiros pré-molares inferiores, tipo I, um canal foi detectado em 70,5% e dois canais em 29,5%; nos segundos pré-molares inferiores, tipo I, um único canal foi detectado em 98,5%. O primeiro molar inferior foi observado com duas raízes em 98% e tres raízes em 2%o. O segundo molar inferior tinha duas raízes em 92,5% dos casos, uma raiz em 6% e tres raízes em 1,5%. A simetria foi maior nas mulheres em comparagao aos homens nos incisivos centrais. CONCLUSÃO: Pode-se concluir que dentes de um mesmo grupo podem apresentar morfologias diferentes no mesmo paciente.

Apical periodontitis in endodontically-treated teeth: association between missed canals and quality of endodontic treatment in a Colombian sub-population. A cross-sectional study.

A high prevalence of post-treatment apical periodontitis associated to variables such as endodontic treatment quality and missed canals has been reported. AIM: The aim of this study was to evalúate the quality of endodontic treatment and the frequency of missed canals associated with teeth with apicalperiodontitis (AP) through CBCTin a Colombian sub-population. MATERIAL AND METHOD: This was a cross-sectional study assessing 318 cone beam computed tomography (CBCT) scans of endodontically treated teeth from Colombian individuals. The scans were taken using J Morita X550 (J Morita Corporation, Osaka, Japan), with voxel size 0.125 to 0.20 mm. All endodontically treated teeth were assessed for quality of treatment, presence of missed canals and AP. Allsamples were analyzed bytwo endodontics specialists and an radiology specialist. Chi-square or Fisher 's test and odds ratio were calculated to identify the association and risk relationship between the presence of AP and the study variables. RESULTS: Missed canals were found in 18.61% (86/462), and 95.3% were associated with AP. The frequency of AP was 62.34% (288/462) for all the evaluated teeth. AP was found in 27.43 % (79/288) of the teeth with adequate endodontic treatment, in contrast to 72.57% (209/288) of the teeth with inadequate treatment (P<0.01). The frequency of missed canals was highest in maxillary molars, with 55.23% (58/105), with 96.55% presenting AP. The second mesiobuccal canal wasthe most frequently missed canal, 88.52%o(54/61), with AP in 90.74% (49/54) of the cases. CONCLUSIÓN: There was a high frequency of teeth with missed canals and PA. More than half of the teeth with missed canals were maxillary molars, with MB2 being the most common canal, commonly presenting apical periodontitis.

Uma alta prevalência de periodontite apical pós-tratamento associada a variáveis como qualidade do tratamento endodôntico e fracasso do tratamento é relatada na literatura. O objetivo deste estudo foi avaliar a qualidade do tratamento endodôntico e a frequência e fracasso do tratamento associados a dentes com periodontite apical (PA) por meio de tomografia computadorizada de feixe cônico (TCFC) em uma subpopulação colombiana. MATERIAL E MÉTODO: Este foi um estudo transversal que avaliou 318 tomografias computadorizadas de dentes tratados endodonticamente de indivíduos colombianos. Os exames foram realizados utilizando o tomógrafo J Morita X550, com tamanho de voxel de 0,125 a 0,20 mm. Todos os dentes tratados endodonticamente foram avaliados quanto à qualidade do tratamento, presença de canais não localizados e AP. Todas as amostras foram avaliadas por dois especialistas em endodontia e um especialista em radiologia. Foram calculados o teste qui-quadrado ou de Fisher e a razão de chances para identificar associação e relação de risco entre a presença de PA e as variáveis do estudo. RESULTADOS: Foram encontrados canais não localizados em 18,61% (86/462) e 95,3% estavam associados à PA. A frequência de AP foi de 62,34% (288/462) para todos os dentes avaliados. AP foi encontrada em 27,43% (79/288) dos dentes com tratamento endodôntico adequado, em contraste com 72,57% (209/288) dos dentes com tratamento inadequado (P<0,01). A frequência de canais não localizados foi maior nos molares superiores, com 55,23% (58/105), sendo que 96,55% apresentavam PA. O canal mésio-palatino (MB2) apresentou maior frequência de canal não localizado (88,52% - 54/61), com PA em 90,74% (49/54) dos casos. CONCLUSÃO: Houve alta frequência de dentes com canais não localizados e com PA. Mais da metade dos dentes com canais não localizados eram molares superiores, sendo o MB2 é o canal com a maior frequência, comumente apresentando periodontite apical.

Systematic review and meta-analysis of root morphology and canal configuration of permanent premolars using cone-beam computed tomography.

INTRODUCTION: The efficacy of root canal treatment is greatly impacted by a thorough understanding of root canal anatomy. This systematic review and meta-analysis aim to thoroughly investigate the root morphology and canal configuration (RMCC) of permanent premolars (PMs). METHODOLOGY: A comprehensive analysis was conducted following the PRISMA guidelines. Literature exploration was carried out across four electronic databases (PubMed, Embase, Cochrane, and Web of Science). The risk of bias assessment was conducted for the included studies utilizing the Anatomical Quality Assessment (AQUA) tool. Data analysis was performed utilizing SPSS and RevMAN5.3.3. The meta-analysis was applied with a 95% confidence interval to calculate odds ratios (OR). RESULTS: Among the 82 selected studies, 59 studies exhibited potential bias in domain one (objective(s) and subject characteristics), followed by domain three (methodology characterization). The majority of maxillary PM1s had either single root (46.7%) or double roots (51.9%), while three-rooted variants were uncommon (1.4%). Conversely, most other PMs exhibited a single root. In terms of canal configuration, maxillary PM1s predominantly featured double distinct canals (87.2%), with the majority of maxillary PM2s displaying either a single canal (51.4%) or double canals (48.3%). Mandibular PMs were primarily characterized by single canals, accounting for 78.3% of mandibular PM1s and 90.3% of mandibular PM2s. Subgroup analyses revealed higher incidences of single-rooted and single-canalled PMs among Asians compared to Caucasians. Additionally, women exhibited a higher incidence of single-rooted PMs, while men showed a greater frequency of double-rooted PMs. CONCLUSIONS: The comprehensive analysis indicated that maxillary PM1s predominantly possess double roots and double canals, whereas maxillary PM2s and mandibular PMs were primarily characterized by single-rooted with a single canal. Notably, single root and single canal were more prevalent among women and Asian samples.

The effect of cone beam computerized tomography voxel size and the presence of root filling on the assessment of middle mesial canals in mandibular molar teeth.

INTRODUCTION: The study aims to compare the detection of the middle mesial canal (MMC) in mandibular molar teeth using cone beam computed tomography (CBCT) with different voxel sizes when the mesiobuccal (MB) and mesiolingual (ML) canals have three distinct phases (unpreparation, preparation and obturation and the removal of the obturation and repreparation). METHODS: Two hundred forty-two extracted human mandibular molars were collected and kept in a physiological saline solution prior to use. 0.2-, 0.28- and 0.35-mm voxel sizes CBCT (n = 242) were performed in three phases (Ph): Ph1, no MB and ML canal preparation or obturation; Ph2, after MB and ML canals preparation and obturation; and Ph3, after the removal of the obturation of MB and ML canals and canals repreparation. Images were analyzed using OnDemand3D® software. After the CBCT acquisition in Ph3, all the samples were clarified to visualize the presence of the MMC directly. A blinded, previously calibrated examiner analyzed all the images. RESULTS: The MMC was detected in 15 of the 242 teeth after the clearing technique. The lowest MMC detection rate was observed at 0.35-mm voxel size regardless of the ML and MB canal condition, while the highest was observed at 0.2-mm voxel size (P < 0.05). There is no statistically significant difference between 0.2-mm and 0.28-mm voxel sizes (P > 0.05). In all voxel sizes, the highest rate of detectability of the MMC was seen in Phase 1, while the lowest was in Phase 2. CONCLUSIONS: It may be appropriate to take a 0.20-mm voxel size CBCT image, especially after the removal of root canal filling. CLINICAL RELEVANCE: An appropriate CBCT voxel size and the absence of root canal filling in the root canal system help to detect the missing MMC.

Volumetric Analysis of Hand and Rotary Instrumentation, Root Canal Filling Techniques, and Obturation Materials in Primary Teeth Using Spiral CT.

AIM AND BACKGROUND: To compare the root canal volume in primary teeth using hand and rotary instruments and to evaluate root canal filling techniques and flow of root canal obturation materials in the postinstrumented root canal volume using spiral computed tomography (SCT). MATERIALS AND METHODS: Freshly extracted 16 primary molars were randomly divided into two groups and subjected to SCT analysis before and after instrumentation. For the manual technique (group I) with eight teeth were prepared using K files, and rotary (group II) eight teeth preparation was performed with ProTaper files. The filled volume in each canal was measured using SCT, and the percentage of obturated volume was calculated. The data were statistically analyzed using the Mann-Whitney U test. RESULTS: There was a statistically significant difference in both groups' volume of root canals enlarged. Even though both K files and the ProTaper system brought about enlarged canals after instrumentation, there was a statistically significant increase in volume after using K files in two canals. In three canals, there was a statistically significant increase in volume after using ProTaper. Irrespective of the obturation technique and materials used, there is no statistically significant difference in the volume after obturation. CONCLUSION: From the results of this study, the ProTaper file system shows suitable volumetric enlargement up to an optimum level, which is needed in primary root canal walls, and is better in canal shaping, as evidenced by good postobturation volume. CLINICAL SIGNIFICANCE: The traditional method of cleaning and shaping the root canals in permanent teeth using manual stainless-steel files can lead to undesirable curvatures in root canal morphology, making correctly filling the root canals difficult. It is also time-consuming and sometimes leads to iatrogenic errors. Rotary nickel-titanium (Ni-Ti) instrumentation techniques have been developed to overcome these problems. How to cite this article: Yadav DBUC, Varma RB, Kumar JS, et al. Volumetric Analysis of Hand and Rotary Instrumentation, Root Canal Filling Techniques, and Obturation Materials in Primary Teeth Using Spiral CT. J Contemp Dent Pract 2024;25(3):250-259.

Evaluation of various obturation techniques with bioceramic sealers in 3D-printed C-shaped canals.

This in vitro study compared various obturation techniques with bioceramic sealers for filling C-shaped 3D-printed replicas. A mandibular molar with a C-shaped root canal with a C1 configuration was obtained. After instrumenting with M3 Pro Gold files (United Dental, Shanghai, China) up to size #30/0.04, a CBCT scan of the tooth was taken. Sixty 3D-printed replicas of the tooth were created. The samples were obturated with EndoSeal TCS sealer (E. TCS; Maruchi, Wonju, Korea) or EndoSeal MTA (E. MTA; Maruchi, Wonju, Korea) (n = 30). The samples in each group were obturated with the following techniques (n = 10): (1) single-cone technique (SC), (2) SC with ultrasonic activation (UA), and (3) cold hydraulic compaction (CHC). Following incubation, the replicas' apical, middle, and coronal thirds were inspected under a digital microscope, and the proportion of filling material and void were calculated. Also, the obturation time and sealer extrusion were recorded. Data were analyzed using ANOVA, LSD post-hoc, and the chi-square tests (α = 0.05). The results indicated that in the apical third, E. TCS-SC, E. TCS-UA, and E. MTA-UA had the lowest void percentage among groups (p < 0.05). In the middle thirds, samples obturated with E. TCS-UA showed a significantly lower void percentage among all groups (p < 0.05). However, in the coronal third, E. TCS-CHC showed the least void percentage (p < 0.05), followed by E. TCS-UA and E. MTA-CHC. The E. TCS-SC and E. TCS-UA were the least time-consuming methods (p < 0.05). Sealer extrusion significantly differed among the groups, with E. MTA-UA and E. TCS-UA showing higher incidence (p = 0.019). It was concluded that E. TCS-UA was the most convenient obturation technique. However, care must be taken when obturating the canals with high flow and ultrasonic activation near the vital anatomical landmarks.

Exploring age and gender variations in root canal morphology of maxillary premolars in Saudi sub population: a cross-sectional CBCT study.

BACKGROUND: In complex teeth like maxillary premolars, endodontic treatment success depends on a complete comprehension of root canal anatomy. The research on mandibular premolars' root canal anatomy has been extensive and well-documented in existing literature. However, there appears to be a notable gap in available data concerning the root canal anatomy of maxillary premolars. This study aimed to explore the root canal morphology of maxillary premolars using cone-beam computed tomography (CBCT) imaging, considering age and gender variations. METHODS: From 500 patient CBCT scans, 787 maxillary premolar teeth were evaluated. The sample was divided by gender and age (10-20, 21-30, 31-40, 41-50, 51-60, and 61 years and older). Ahmed et al. classification system was used to record root canal morphology. RESULTS: The most frequent classifications for right maxillary 1st premolars were 2MPM1 B1 L1 (39.03%) and 1MPM1 (2.81%), while the most frequent classifications for right maxillary 2nd premolars were 2MPM1 B1 L1 (39.08%) and 1MPM1 (17.85%). Most of the premolars typically had two roots (left maxillary first premolars: 81.5%, left maxillary second premolars: 82.7%, right maxillary first premolars: 74.4%, right maxillary second premolars: 75.7%). Left and right maxillary 1st premolars for classes 1MPM1 and 1MPM1-2-1 showed significant gender differences. For classifications 1MPM1 and 1MPM1-2-1, age-related changes were seen in the left and right maxillary first premolars. CONCLUSION: This study provides novel insights into the root canal anatomy of maxillary premolars within the Saudi population, addressing a notable gap in the literature specific to this demographic. Through CBCT imaging and analysis of large sample sizes, the complex and diverse nature of root canal morphology in these teeth among Saudi individuals is elucidated. The findings underscore the importance of CBCT imaging in precise treatment planning and decision-making tailored to the Saudi population. Consideration of age and gender-related variations further enhances understanding and aids in personalized endodontic interventions within this demographic.

Micro-computed tomographic analysis of the morphology of maxillary lateral incisors.

OBJECTIVE: This study aimed to investigate the morphology of maxillary lateral incisors (MxLI) using micro-computed tomography (micro-CT). MATERIALS AND METHODS: The root canal configurations (RCC) of maxillary lateral incisors (MxLI) of a mixed Swiss-German population were examined using micro-CT, 3D imaging, and a 4-digit system code indicating the main root canal from coronal to apical thirds and the main foramina number. RESULTS: The most frequently observed RCC of MxLI were 1-1-1/1 (Vertucci I/Ve I, 80.0%), 1-1-2/2 (Ve V, 7.3%), 1-2-1/1 (Ve III, 6.4%), 2-1-1/1 (Ve II, 1.8%), and 1-1-1/2 (1.8%)(n = 110). Three additional RCC were observed less frequently (0.9%). The MxLI showed one physiological foramen in 89.1%, two in 9.1%, and seldom three (1.8%). Most accessory canals were identified in the apical third of a root (20.0%), and no accessory canals in 72.7% of the samples. CONCLUSIONS: Detailed information on the internal morphology of MxLI of a Swiss-German population is given. The most frequently observed RCC of MxLI is 1-1-1/1 (Ve I). However, accessory canals may occur in all apical thirds, and 20% of all teeth investigated showed a challenging RCC for clinical treatment. CLINICAL RELEVANCE: This study offers clinicians comprehensive data on MxLI morphology, emphasizing the significance of understanding varied RCC and accessory canal presence for improving root canal treatment outcomes. Over 25% of teeth exhibited complex RCC or accessory canals, influencing decisions during root canal treatment.

Cone-beam computed tomography evaluation of shaping ability of kedo-S square and fanta AF™ baby rotary files compared to manual K-files in root canal preparation of primary anterior teeth.

BACKGROUND: Pediatric rotary file systems were developed to solve manual file limitations. With many systems available, it may be tricky to select the most appropriate one. AIM: to assess & compare Kedo-S Square, Fanta-AF™-Baby rotary files with manual K-file concerning removed dentin amount, canal transportation, centric ability & root canal taper using CBCT in primary anterior teeth. DESIGN: Extracted Seventy-five upper primary anterior teeth with intact 2/3 root length were collected and divided into three groups based on root canal instrumentation, group-I: prepared using K-file, group-II: prepared using Kedo-S Square, and group-III: prepared using Fanta AF™ Baby file. The teeth were imaged with CBCT before & following canal instrumentation. Then, the removed dentin amount was calculated at each root-canal level. The Kruskal-Wallis test was utilized to statistically analyze study data. RESULT: The difference among the three groups was highly statistically significant at cervical & apical thirds concerning dentin thickness changes on both mesial & distal sides following canal preparation with the least removed dentin in the Kedo-S Square group(P < 0.0001). Regarding transportation & centering ability, a non-significant difference between the three groups was found. 80% of the Fanta AF™ Baby group had good-tapered preparation compared to the Kedo-S Square (72%) and K-file (40%) groups(P < 0.05). CONCLUSION: Kedo-S Square was preferable to Fanta-AFTM-Baby & manual K-files in primary root canal preparation.

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.

A systematic review and meta-analysis of the prevalence and global distribution of middle mesial canals in mandibular molars identified by CBCT.

OBJECTIVES: This systematic review and meta-analysis aimed to evaluate the prevalence of middle mesial canal (MMC) in permanent mandibular molars of different populations and regions based on cone-beam computed tomography (CBCT) studies. MATERIALS AND METHODS: PubMed, Scopus, Embase, Web of Science, and Open-Grey were searched up to October 2023 according to specific keywords. A hand search was conducted on the references of the included studies and articles from three peer-reviewed journals in endodontics. The main variable of interest was the prevalence of MMC. Additional data such as the total number of included cases, age and country of the population, CBCT device information, voxel size, and field of view details were also extracted. Extracted data were analyzed qualitatively with the JBI quality assessment checklist and quantitatively with STATA software. RESULTS: Of 32,793 studied teeth, the cumulative prevalence of MMC in both mandibular 1st and 2nd molars was 3.11% (95% CI: 2.00-4.44%). The subgroup analysis reveals a prevalence of 4.15% (95% CI: 2.69-5.89%) for mandibular 1st molars and 1.2% (95% CI: 0.2-2.83%) for mandibular 2nd molars. The highest prevalence of MMC in 1st molar was attributed to South Asia (11.24%) and Africa (6.61%). CONCLUSIONS: The prevalence of MMC varies among regions. Clinicians should be aware of the potential prevalence of MMC, particularly in mandibular first molars, as a missed MMC could result in endodontic failure. CLINICAL RELEVANCE: The presence of MMCs varies in different geographic regions (0% to 29.7%). Clinicians should always look for MMC when doing an endodontic treatment on mandibular molars, as the presence of this canal is not uncommon. We suggest searching for this canal as if searching for the second mesiobuccal canal of maxillary 1st molars.

Influence of root shape on canal complexity at the mandibular molar apical surgical resection level: A micro-CT study.

OBJECTIVES: This study aimed to investigate the relationship between the aspect ratios of mandibular molar roots at the apical 3-mm level and their root canal complexity. DESIGN: This study used micro-CT imaging to analyze 163 two-rooted mandibular molars. The aspect ratios of the roots at the apical 3-mm level were categorized as "< 2.75" or "≥ 2.75" (mesial) and "< 1.75" or "≥ 1.75" (distal). A two-dimensional (2D) analysis focused on four apical axial cross-section levels to determine the presence of main and accessory canals and isthmus. Additionally, a three-dimensional (3D) assessment of the apical 4-mm of both roots examined main and accessory canals, apical foramina, apical deltas, and middle mesial canals. RESULTS: Mesial roots with aspect ratios ≥ 2.75 showed a higher number of main canals at all levels compared to those with aspect ratios < 2.75 at the 3-mm level. Additionally, the ≥ 2.75 group exhibited more accessory canals and a higher average number of accessory canals. The 3D assessment confirmed significantly more accessory canals and apical foramina in the ≥ 2.75 group. The prevalence of roots with apical deltas was nearly double in the ≥ 2.75 group, and middle mesial canals were exclusively found in this group. In the distal root, the ≥ 1.75 group showed a significantly higher number of main canals at all axial levels. No significant differences were observed between groups in terms of accessory canals, apical foramina, or deltas. CONCLUSIONS: A higher root aspect ratio is related to higher anatomical complexity.

Efficacy of electronic apex locators in comparison with intraoral radiographs in working length determination- a systematic review and meta-analysis.

BACKGROUND: Successful endodontic treatment needs accurate determination of working length (WL). Electronic apex locators (EALs) were presented as an alternative to radiographic methods; and since then, they have evolved and gained popularity in the determination of WL. However, there is insufficient evidence on the post-operative pain, adequacy, and accuracy of EALs in determining WL. OBJECTIVE: The systematic review and meta-analysis aims to gather evidence regarding the effectiveness of EALs for WL determination when compared to different imaging techniques along with postoperative pain associated with WL determination, the number of radiographs taken during the procedure, the time taken, and the adverse effects. METHODS: For the review, clinical studies with cross-over and parallel-arm randomized controlled trials (RCTs) were searched in seven electronic databases, followed by cross-referencing of the selected studies and related research synthesis. Risk of bias (RoB) assessment was carried out with Cochrane's RoB tool and a random-effects model was used. The meta-analysis was performed with the RevMan software 5.4.1. RESULTS: Eleven eligible RCTs were incorporated into the review and eight RCTs into the meta-analysis, of which five had high RoB and the remaining six had unclear RoB. Following meta-analysis, no significant difference in postoperative pain was found among the EAL and radiograph groups (SMD 0.00, CI .29 to .28, 354 participants; P value = 0.98). Radiograph group showed better WL accuracy (SMD 0.55, CI .11 to .99, 254 participants; P value = 0.02), while the EAL group had 10% better WL adequacy (RR 1.10, CI 1.03-1.18, 573 participants; P value = 0.006). CONCLUSION: We found very low-certainty evidence to support the efficacy of different types of EAL compared to radiography for the outcomes tested. We were unable to reach any conclusions about the superiority of any type of EAL. Well-planned RCTs need to be conducted by standardizing the outcomes and outcome measurement methods.

Morphology and classification of the second mesiobuccal canal in maxillary first molars: a cone-beam computed tomography analysis in a Chinese population.

BACKGROUND: Understanding the tooth anatomy is crucial for ensuring effective endodontic treatment. This study investigated the root canal morphology of the second mesiobuccal (MB2) canal in maxillary first molars (MFMs) in a Chinese population using cone-beam computed tomography (CBCT). METHODS: This study evaluated 486 MFMs with MB2 canals from 285 participants undergoing CBCT examination and determined the Vertucci's classification and position of the MB2 canal orifice. The prevalence of the MB2 canal was correlated with the sex, age, and tooth side. The correlations between the prevalence of the MB2 canal and sex and tooth side were assessed using the Fisher's exact test. The chi-square test was used for evaluating the correlation between the prevalence of the MB2 canal and age. RESULTS: The number of type II, III, IV, V, VI, VII, and other root canals in the MFMs was 30.9%, 0.6%, 65.0%, 1.2%, 1.2%, 0.4%, and 0.6%, respectively. Among the 201 cases with bilateral inclusion, 87.6% showed consistent canal configuration. Results of the first clear apparent position (FCAP) of the MB2 canals showed that 434, 44, and 3 teeth had FCAP at the upper, middle, and bottom one-third of the root, respectively. The FCAPs of the MB2 canal in the MFMs with types II, IV, and VI, as well as types III and V canals showed significant differences (p<0.05). The horizontal distance between the MB1 and MB2 canal orifices in the type II canals of MFMs was significantly lesser than those in the type IV canals of MFMs (p < 0.01). The longitudinal distance between the pulp chamber floor plane and MB2 canal orifice significantly correlated with age (p < 0.05). CONCLUSIONS: The morphology of the mesiobuccal root canal in the MFMs is complex. Complete understanding of the anatomical morphology of the root canal combined with the CBCT and dental operating microscope is necessary for the accurate detection of the MB2 canal and consequently improved success rate of root canal treatment. Our study findings can help endodontists improve endodontic treatment outcomes.

Micro-computed tomography (micro-CT) evaluation of root canal morphology in immature maxillary third molars.

The endodontic treatment of immature permanent teeth with necrotic pulp is a significant clinical challenge. The success of regenerative endodontic procedure is highly dependent on disinfection of the root canal and an accurate anatomical knowledge of the root canal. The aim of this study was to use micro-computed tomography (micro-CT) analysis to investigate the configuration of root canals in the upper permanent third maxillary molars with incomplete root development in their coronal, apical and middle third portions. Thirty immature third permanent maxillary molars were scanned using a micro-CT system. Then, we measured the diameters and areas of the root canal in the coronal, middle and apical third of the roots. The ratio between the long and short diameter of each root canal was then calculated and the canals were divided into several groups: round, oval, long oval, flat and irregular. The round configuration was not observed in the distobuccal and mesiobuccal roots in any of their anatomical regions. Oval and long oval canals predominated in the distobuccal root. The greatest variations were observed in the mesiobuccal root, with the ribbon-shaped canal predominating in the middle region and an irregular shape in the apical region. In the coronal region of the palatal canal, the round configuration predominated; in the middle third, we observed an almost equivalent distribution between round and oval configurations; apically, the oval shape predominated. In conclusion, we observed significant complexity and variation in the morphology and configuration of root canals in immature permanent molars, thus generating additional obstacles for the success of regenerative endodontics.

Micro-computed tomographic evaluation on the quality of single-cone obturation using a modified passive-deflation sealer injection needle: an in vitro study.

OBJECTIVES: This study aimed to design a modified passive-deflation sealer injection needle and investigate its ability to improve obturation quality of single-cone technique through assessing the distribution of voids in root canals using micro-computed tomography (micro-CT). MATERIALS AND METHODS: Forty-eight mandibular incisors were divided into eight groups (n = 6), according to the taper of root canal preparation (0.06 or 0.04), the needle used for sealer injection (modified or commercial iRoot SP injection needle), and the obturation method (iRoot SP sealer-only or single-cone obturation). After obturation, each specimen was scanned by micro-CT. The volumetric percentage and distribution of all voids were first analyzed and compared among groups, then the open and closed voids were separately analyzed and compared among single-cone obturation groups. RESULTS: Compared to commercial needle groups, modified needle groups showed much less voids, especially in the apical root canal part (P < 0.05). Besides, the modified needle groups produced much less open voids than commercial needle groups despite the root canal taper (P < 0.05). CONCLUSIONS: The modified passive deflation sealer injection needle could effectively improve the quality of single-cone obturation through reducing intra-canal voids, especially open voids throughout the root canal, thus might possibly be developed as an effective intra-canal sealer delivering instrument.

Three-Dimensional Measurement of Obturation Quality of Bioceramic Materials in Filling Artificial Internal Root Resorption Cavities Using Different Obturation Techniques: An In Vitro Comparative Study.

INTRODUCTION: Pathologic conditions such as internal root resorption (IRR) may complicate root canal filling. This study aimed to evaluate and compare the obturation quality by measuring the percentage of obturation volume (POV) in root canals with artificial IRR obturated with different materials and techniques using cone beam computed tomography (CBCT). METHODS: Forty single canal extracted mandibular premolars were decoronated to standardize their length to 14 mm. Following instrumentation, the roots were cut horizontally, and artificial IRR cavities were made at the level of 7 mm from the apex. The root halves were joined using cyanoacrylate adhesive. The samples were randomly assigned to 4 groups (n = 10), and the canals were filled as follows: single-cone technique (SC), bulk-fill Bio-C Sealer (BF), and Bio-C Repair for the coronal and middle third (BCR) + cold lateral condensation technique (CLC) for the apical third and continuous wave compaction technique (CWC). The pre- and postobturation volumes and the POV were measured in the total canal and for the apical, middle, and coronal thirds separately using CBCT and Mimics Medical software. The results were analyzed statistically using one-way ANOVA and Tukey HSD test, and statistical significance was set at P < .05. RESULTS: BF group resulted in significantly lower total, coronal, middle and apical POV values compared to SC, BCR + CLC, and CWC groups (P < .05), respectively. Also, at the apical third, the BCR + CLC group showed significantly lower POV than the SC and CWC groups (P < .05), respectively. The intra-group comparison showed that BF and BCR + CLC groups had a significantly lower POV in the apical third compared to the middle third (P < .05). Conversely, the CWC group had a significantly higher apical POV than the middle third (P < .05). CONCLUSIONS: The maximum POV was obtained using the CWC technique, Bio-C Repair, and SC technique with Bio-C Sealer, making their application in IRR more preferable than the BF Bio-C Sealer.

Selecting drill size for post space preparation based on final endodontic radiographs: An in vitro study.

BACKGROUND: For placement of intraradicular posts the intracanal filling material has to be removed. If drills are employed for this purpose, extra widening of the canal, incomplete cracks or root perforation are probable when inappropriate size of drill is used. OBJECTIVE: This in vitro study assessed the efficacy of radiographs taken after completion of root canal therapy in selecting the appropriate-sized Peeso reamer for post space preparation. METHODS: Canals of 53 extracted maxillary and mandibular teeth of different types were cleaned and shaped. Then with acrylic resin 3-dimensional model of the intracanal space of each tooth was fabricated. Next, all canals were filled with gutta-percha and teeth were radiographed buccolingually. Based on these radiographs two observers selected a Peeso reamer that best matched each canal's diameter. The diameter of the selected Peeso reamer was compared to the diameter of the corresponding resin model of each canal by two independent observers and the difference was measured. The data were analyzed by paired sample t-test using SPSS version 22. RESULTS: The diameter of the selected Peeso reamers ranged from 0.21 mm smaller to 0.12 mm larger than the diameter of intracanal spaces. The difference between reamer and resin model was less than 0.1 mm in 75% of the cases. CONCLUSION: The result of this study suggests that post-operation endodontic radiographs are reliable means for selecting a size of Peeso reamer that does not encroach on dentinal wall during removal of intracanal filling material and post space preparation.

Microcomputed tomography analysis of curved root canal preparation when coronal flaring and glide path files used with heat-treated nickel titanium rotary files.

The objective was to evaluate the effect of glide path and coronal flaring on the dentin volume removal and percentage of touched walls in curved canals using two heat-treated rotary files. The mesiobuccal canal of forty-eight, randomly selected, extracted mandibular molars was divided into two groups of 24 each, according to the type of instrument used (RACE EVO and EdgeSequel rotary files). Each group was further divided into three subgroups; Group (A): Control using one file shaped to 04/30, Group (B) with a glide path (EdgeGlidePath (EGP)), and Group (C): with a glide path and coronal flaring (EGP and EdgeTaper Platinum (ETP) SX file respectively). The root canals were then instrumented using the assigned instruments. The assessment was carried out using micro-CT. The comparison of the mean values of the tested groups about dentin volume removal and percentage of untouched walls did not reach statistical significance (p<0.05). Glide path and coronal flaring had an insignificant effect on the dentin volume removal and percentage of untouched walls in curved canals.