Differential diagnosis of cemento-osseous dysplasia and periapical cyst using texture analysis of CBCT.

BACKGROUND: Radiolucencies found at the root apex in patients with cemento-osseous dysplasia (COD) may be mistaken for periapical cysts (PC) of endodontic origin. The purpose of this study was to examine the utility of quantitative texture analysis using cone-beam computed tomography (CBCT) to differentiate between COD and PC. METHODS: Patients who underwent CBCT at Wonkwang University Daejeon Dental Hospital between January 2019 and December 2022 and were diagnosed with COD and PC by clinical, radiologic, and, if necessary, histopathologic examination were included. Twenty-five patients each were retrospectively enrolled in the COD and PC group. All lesions observed on axial CBCT images were manually segmented using the open-access software MaZda version 4.6 to establish the regions of interest, which were then subjected to texture analysis. Among the 279 texture features obtained, 10 texture features with the highest Fisher coefficients were selected. Statistical analysis was performed using the Mann-Whitney U-test, Welch's t-test, or Student's t-test. Texture features that showed significant differences were subjected to receiver operating characteristics (ROC) curve analysis to evaluate the differential diagnostic ability of COD and PC. RESULTS: The COD group consisted of 22 men and 3 women, while the PC group consisted of 14 men and 11 women, showing a significant difference between the two groups in terms of sex (p=0.003). The 10 selected texture features belonged to the gray level co-occurrence matrix and included the sum of average, sum of entropy, entropy, and difference of entropy. All 10 selected texture features showed statistically significant differences (p<0.05) when comparing patients with COD (n=25) versus those with PC (n=25), osteolytic-stage COD (n=11) versus PC (n=25), and osteolytic-stage COD (n=11) versus cementoblastic-stage COD (n=14). ROC curve analysis to determine the ability to differentiate between COD and PC showed a high area under the curve ranging from 0.96 to 0.98. CONCLUSION: Texture analysis of CBCT images has shown good diagnostic value in the differential diagnosis of COD and PC, which can help prevent unnecessary endodontic treatment, invasive biopsy, or surgical intervention associated with increased risk of infection.

Artificial intelligence in diagnosing dens evaginatus on periapical radiography with limited data availability.

This study aimed to develop an artificial intelligence (AI) model using deep learning techniques to diagnose dens evaginatus (DE) on periapical radiography (PA) and compare its performance with endodontist evaluations. In total, 402 PA images (138 DE and 264 normal cases) were used. A pre-trained ResNet model, which had the highest AUC of 0.878, was selected due to the small number of data. The PA images were handled in both the full (F model) and cropped (C model) models. There were no significant statistical differences between the C and F model in AI, while there were in endodontists (p = 0.753 and 0.04 in AUC, respectively). The AI model exhibited superior AUC in both the F and C models compared to endodontists. Cohen's kappa demonstrated a substantial level of agreement for the AI model (0.774 in the F model and 0.684 in C) and fair agreement for specialists. The AI's judgment was also based on the coronal pulp area on full PA, as shown by the class activation map. Therefore, these findings suggest that the AI model can improve diagnostic accuracy and support clinicians in diagnosing DE on PA, improving the long-term prognosis of the tooth.

Effect of orthodontic treatment on the periapical radiolucency of endodontically treated teeth: a CBCT analysis.

BACKGROUND: This study aimed to evaluate periapical radiolucency of endodontically treated teeth before and after orthodontic treatment using cone-beam computed tomography (CBCT). METHODS: Patients who underwent orthodontic treatment at Wonkwang University Daejeon Dental Hospital between January 2009 and June 2022 were included based on the following criteria: root canal treatment, and availability of CBCT images taken before and after orthodontic treatment with an interval of > 1 year between both scans. Patients with primary teeth or orthodontic tooth extractions were excluded. The size of the periapical radiolucency (SPR) of the endodontically treated tooth was evaluated using CBCT. Pre-orthodontic treatment CBCT images and the latest post-orthodontic treatment CBCT images were analyzed. The selected teeth were further categorized based on the orthodontic duration, CBCT interval, the patient sex and age, the tooth type and position (maxilla or mandible), and quality of root canal obturation. Statistical analyses were performed to evaluate changes in SPR using the paired t-test and multiple regression analysis. RESULTS: In total, 115 teeth (37 anterior teeth, 22 premolars and 56 molars) from 61 patients (age, 14-54 years) were included, with 39 teeth from male patients and 76 teeth from female patients. The age was ranged between 14 and 54 years old, and mean age was 25.87 years old. The mean CBCT interval and orthodontic treatment period were 43.32 months and 36.84 months, respectively. Seventy-five teeth showed good obturation quality, 80 were not used as anchors during orthodontic treatment, and 71 were maxillary. The SPR size increased after orthodontic treatment for 56 teeth and decreased for 59 cases. The average change in SPR was -0.102 mm and the difference was not significant. Significant decrease of SPR were observed between female patients (p = 0.036) and maxillary teeth (p = 0.040). CONCLUSION: Orthodontic treatment had no significant impact on the changes in the SPR in endodontically treated teeth in most categories. However, there was a significant difference among females and the maxillary teeth. In both categories, the size of radiolucency decreased significantly.

Assessment of reliability and information quality of YouTube videos about root canal treatment after 2016.

BACKGROUND: This study aimed to assess and update the content, reliability, and information quality of content related to root canal treatment (RCTx) on YouTube and evaluate the correlation between each evaluation index. METHODS: YouTube was searched using two terms related to RCTx ("root canal and endodontic treatment"). A total of 240 videos (120 for each search term) were screened. Exclusion criteria were as follows: no sound or visuals, non-English, irrelevant to the search term, longer than 15 min, duplicate, or old (uploaded before 2016). After exclusion, 50 videos of "root canal treatment" and 45 videos of "endodontic treatment" were analyzed. Video length, total number of views, likes, dislikes, comments, and days since upload were recorded using descriptive video data. Viewers' interaction, reliability and information quality of the video, and quality of video content were measured using nondescriptive video data. The interaction index and video power index were used for viewer interactions, and the modified DISCERN index, JAMA criteria, and Global Quality Score were used to assess the reliability and information quality of the video. The quality of the video content was measured using the completeness score. RESULTS: The videos of the "root canal treatment" group had a significantly higher completeness score for the etiology and symptoms (p < 0.05), and videos of the "endodontic treatment" group showed a higher interaction index, completeness score for the procedure (p < 0.05). Videos for dentists had significantly higher completeness scores for the procedure, while videos for laypersons had higher completeness scores for etiology, anatomy, symptoms, and prognosis (p < 0.05). Furthermore, the total completeness score and the interaction index of the videos for laypersons were significantly higher (p < 0.05). The videos uploaded by the university had a significantly higher modified DISCERN index (p = 0.044), and the JAMA score was significantly higher in the commercial group (p = 0.001). CONCLUSIONS: Although the accuracy of videos related to RCTx was higher in videos by universities and professionals, the total completeness of YouTube videos was low regardless of the video source. Therefore, professionals should be responsible for providing more accurate and reliable videos.

Mandibular incisors with two canals are associated with the presence of the distolingual root in mandibular first molars: a cone-beam computed tomographic study.

BACKGROUND: This study aimed to evaluate the root canal configurations and the association between mandibular first molars and distolingual root (DLR) and mandibular incisors using cone-beam computed tomography (CBCT). METHODS: Mandibular first molars and incisors were evaluated using CBCT images of 150 patients. Mandibular first molars were classified according to the presence or absence of DLR. The curvature of the DLR was evaluated using Schneider's method in buccolingual and mesiodistal orientations. The angle of the mesiolingual-distolingual-distobuccal canal orifices (ML-DL-DB) was evaluated at the pulpal floor level. The mandibular central and lateral incisors were classified as either single canal or two canals. The association between the root canal system of the mandibular first molar and mandibular incisors was evaluated. Data were analyzed using the Chi-square test, Student's t-test, and odds ratios from binary logistic regression. The significance level was set at 5%. RESULTS: The frequency of mandibular first molars with DLR was 27.0% and that of mandibular incisors with two canals was 25.8%. The curvature of the DLR was 37.1° in the buccolingual orientation and 10.4° in the mesiodistal orientation. The angle of ML-DL-DB was 79.0°. The presence of two canal systems in mandibular incisors was associated with the presence of DLR in the mandibular first molar (left central incisors: p = 0.001, odds ratio = 4.25; left lateral incisors: p < 0.001, odds ratio = 3.8; right central incisors: p = 0.003, odds ratio = 3.86; right lateral incisors: p = 0.001, odds ratio = 3.44) but not with the curvature of the DLR or angle of the ML-DL-DB orifice (p > 0.05). CONCLUSIONS: The mandibular first molar showed a high incidence of separate DLRs. It was confirmed that DLR in the mandibular first molar is highly associated with the presence of two-canal system in the mandibular incisors. This association can aid clinicians in successful endodontic treatments.

Comparison of the canal transportation of ProTaper GOLD, WaveOne GOLD, and TruNatomy in simulated double-curved canals.

BACKGROUND: In root canal preparations, it is important to maintain the original canal shape. However, it is difficult to accomplish this, especially due to the complex canal anatomy. This study aimed to compare the shaping ability of the ProTaper GOLD, WaveOne GOLD, and newly developed TruNatomy in simulated S-shaped canals. METHODS: The root canals of 60 S-shaped resin blocks were dyed using ink and photographed. The blocks were then randomly divided into three groups: group ProTaper GOLD (n = 20), WaveOne GOLD (n = 20), and TruNatomy (n = 20). The simulated canals were instrumented according to the NiTi file system and photographed again after being dyed with red ink. The pre- and post-preparation images were superimposed, and the amount of resin removed from both the mesial and distal sides of the canal measured up to 9 mm from the apical terminus, with a 1 mm increment. The preparation time was also calculated. A paired t-test was used to determine the degree of deviation at different levels within the groups. To compare the degree of transportation at different levels between the groups, one-way ANOVA and Kruskal-Wallis tests were performed according to the normality. RESULTS: TruNatomy showed a significant deviation between the mesial and distal sides of the canal only in the coronal area at 6, 7, 8, and 9 mm levels of the canal (p < 0.05). When comparing the amount of transportation in the 3 groups at 9 different levels, TruNatomy showed significantly less canal transportation than the other groups at the 3-and 5-mm levels of the canal (p < 0.05), while ProTaper GOLD showed the largest amount of transportation in the apical curved area at the 2 and 3 mm levels (p < 0.05). TruNatomy removed less resin than other groups in all sections (p < 0.05), while ProTaper GOLD removed slightly more resin than WaveOne GOLD; however, there was no significant difference (p = 0.043). Shaping time was the least for TruNatomy, followed by the WaveOne GOLD and ProTaper GOLD (p < 0.05). CONCLUSIONS: TruNatomy maintained the original apical canal curvature in S-shaped curved canals better than ProTaper GOLD and WaveOne GOLD.

The effect of different confluence confirmation strategies on the obturation of Vertucci type II canal: micro-CT analysis.

OBJECTIVES: The present study aims to compare the obturation quality of 2 confluence confirmation techniques in artificial maxillary first premolars showing Vertucci type II root canal configuration. MATERIALS AND METHODS: Thirty artificial maxillary premolars having Vertucci type II root canal configuration were made. They were divided into 3 groups according to the confluence confirmation technique as follows. Gutta-percha indentation (GPI) group (confluence confirmation using a gutta-percha cone and a K file); electronic apex locator (EAL) group (confluence confirmation using K files and EAL); and no confluence detection (NCD) group. In the GPI group and the EAL group, shaping and obturation were performed with the modified working length (WL). In the NCD group, shaping was performed without WL adjustment and obturation was carried out with an adjusted master cone. Micro-computed tomography was used before preparation and after obturation to calculate the percentage of gutta-percha occupied volume (%GPv) and the volume increase in the apical 4 mm. Data were analyzed using 1-way analysis of variance and post hoc Tukey's test. RESULTS: Statistically significant difference was not found in terms of the %GPv from the apex to apical 4 mm. However, the NCD group showed a statistically significant volume increase compared with the EAL group (p < 0.05). CONCLUSIONS: In terms of gutta-percha occupied volume, no significant difference was observed among the 3 groups. Confluence confirmation using an EAL in teeth with Vertucci type II configuration showed less volume increase during canal shaping compared with no confluence confirmation.

Deep-learning for predicting C-shaped canals in mandibular second molars on panoramic radiographs.

OBJECTIVE: The aim of this study was to evaluate the use of a convolutional neural network (CNN) system for predicting C-shaped canals in mandibular second molars on panoramic radiographs. METHODS: Panoramic and cone beam CT (CBCT) images obtained from June 2018 to May 2020 were screened and 1020 patients were selected. Our dataset of 2040 sound mandibular second molars comprised 887 C-shaped canals and 1153 non-C-shaped canals. To confirm the presence of a C-shaped canal, CBCT images were analyzed by a radiologist and set as the gold standard. A CNN-based deep-learning model for predicting C-shaped canals was built using Xception. The training and test sets were set to 80 to 20%, respectively. Diagnostic performance was evaluated using accuracy, sensitivity, specificity, and precision. Receiver-operating characteristics (ROC) curves were drawn, and the area under the curve (AUC) values were calculated. Further, gradient-weighted class activation maps (Grad-CAM) were generated to localize the anatomy that contributed to the predictions. RESULTS: The accuracy, sensitivity, specificity, and precision of the CNN model were 95.1, 92.7, 97.0, and 95.9%, respectively. Grad-CAM analysis showed that the CNN model mainly identified root canal shapes converging into the apex to predict the C-shaped canals, while the root furcation was predominantly used for predicting the non-C-shaped canals. CONCLUSIONS: The deep-learning system had significant accuracy in predicting C-shaped canals of mandibular second molars on panoramic radiographs.

Comparative evaluation of volumetric changes of three different retrograde calcium silicate materials placed under different pH condititions.

BACKGROUND: The present study aimed to compare the volumetric changes of three calcium silicate cements after retrofilling and placing under different pH conditions via micro-computed tomography (micro-CT) scan. METHODS: Forty-two extracted human single-rooted teeth were randomly assigned to three groups according to the retrofilling materials used (Biodentine, Endocem MTA, and ProRoot MTA). Each group was divided into two subgroups according to the setting condition. The teeth in one group were immersed in normal saline for 5 days at room temperature, and the teeth in the other group were immersed in butyric acid (pH = 5.4) for 5 days at room temperature. The volume ratios of the retrofilling material were calculated via micro-CT imaging. RESULTS: The volume ratios of the Biodentine and Endocem MTA groups were significantly different between the two setting environment, and these groups had significantly lower filled volume ratio (Vf, %) in the acidic environment than in the saline environment (pH = 5.4). Meanwhile, the volume ratio of the ProRoot MTA group did not significantly differ between the two setting environments. All materials under the acidic setting condition had relative radiolucency in the area in contact with the acidic solution. CONCLUSION: The Vf ratio of the Biodentine and Endocem MTA cements was significantly lower in the acidic environment than in the saline environment. No statistically significant difference was observed in the Vf ratio of ProRoot MTA between the two setting environments.

Root canal volume change and transportation by Vortex Blue, ProTaper Next, and ProTaper Universal in curved root canals.

OBJECTIVES: The aim of this study was to compare root canal volume change and canal transportation by Vortex Blue (VB; Dentsply Tulsa Dental Specialties), ProTaper Next (PTN; Dentsply Maillefer), and ProTaper Universal (PTU; Dentsply Maillefer) nickel-titanium rotary files in curved root canals. MATERIALS AND METHODS: Thirty canals with 20°-45° of curvature from extracted human molars were used. Root canal instrumentation was performed with VB, PTN, and PTU files up to #30.06, X3, and F3, respectively. Changes in root canal volume before and after the instrumentation, and the amount and direction of canal transportation at 1, 3, and 5 mm from the root apex were measured by using micro-computed tomography. Data of canal volume change were statistically analyzed using one-way analysis of variance and Tukey test, while data of amount and direction of transportation were analyzed using Kruskal-Wallis and Mann-Whitney U test. RESULTS: There were no significant differences among 3 groups in terms of canal volume change (p > 0.05). For the amount of transportation, PTN showed significantly less transportation than PTU at 3 mm level (p = 0.005). VB files showed no significant difference in canal transportation at all 3 levels with either PTN or PTU files. Also, VB files showed unique inward transportation tendency in the apical area. CONCLUSIONS: Other than PTN produced less amount of transportation than PTU at 3 mm level, all 3 file systems showed similar level of canal volume change and transportation, and VB file system could prepare the curved canals without significant shaping errors.

Corrigendum: Corrections to the funding. Quantification of the tug-back by measuring the pulling force and micro computed tomographic evaluation.

[This corrects the article on p. 273 in vol. 42, PMID: 29142875.].

Quantification of the tug-back by measuring the pulling force and micro computed tomographic evaluation.

OBJECTIVES: The aims of this study were to quantify tug-back by measuring the pulling force and investigate the correlation of clinical tug-back pulling force with in vitro gutta-percha (GP) cone adaptation score using micro-computed tomography (µCT). MATERIALS AND METHODS: Twenty-eight roots from human single-rooted teeth were divided into 2 groups. In the ProTaper Next (PTN) group, root canals were prepared with PTN, and in the ProFile (PF) group, root canals were prepared using PF (n = 14). The degree of tug-back was scored after selecting taper-matched GP cones. A novel method using a spring balance was designed to quantify the tug-back by measuring the pulling force. The correlation between tug-back scores, pulling force, and percentage of the gutta-percha occupied area (pGPOA) within apical 3 mm was investigated using µCT. The data were analyzed using Pearson's correlation analysis, one-way analysis of variance (ANOVA) and Tukey's test. RESULTS: Specimens with a strong tug-back had a mean pulling force of 1.24 N (range, 0.15-1.70 N). This study showed a positive correlation between tug-back score, pulling force, and pGPOA. However, there was no significant difference in these factors between the PTN and PF groups. Regardless of the groups, pGPOA and pulling force were significantly higher in the specimens with a higher tug-back score (p < 0.05). CONCLUSIONS: The degree of subjective tug-back was a definitive determinant for master cone adaptation in the root canal. The use of the tug-back scoring system and pulling force allows the interpretation of subjective tug-back in a more objective and quantitative manner.

Healing outcomes of root canal treatment for C-shaped mandibular second molars: a retrospective analysis.

OBJECTIVES: This study aimed to evaluate the healing rate of non-surgical endodontic treatment between C-shaped and non-C-shaped mandibular second molars. MATERIALS AND METHODS: Clinical records and radiological images of patients who had undergone endodontic treatment on mandibular second molars between 2007 and 2014 were screened. The periapical index scoring system was applied to compare healing outcomes. Information about preoperative and postoperative factors as well as the demographic data of the patients was acquired and evaluated using chi-square and multinomial logistic regression tests. RESULTS: The total healing rate was 68.4%. Healing rates for the mandibular second molar were 70.9% in C-shaped canals (n = 79) and 66.6% in non-C-shaped ones (n = 117). The difference was not statistically significant. CONCLUSIONS: The presence of a C-shaped canal in the mandibular second molar did not have a significantly negative effect on healing after treatment. Instead, proper pulpal diagnosis and final restoration were indicated as having significantly greater influence on the healing outcomes of C-shaped and non-C-shaped canals, respectively.

Prevalence and features of distolingual roots in mandibular molars analyzed by cone-beam computed tomography.

PURPOSE: This study evaluated the prevalence of distolingual roots in mandibular molars among Koreans, the root canal system associated with distolingual roots, and the concurrent appearance of a distolingual root in the mandibular first molar and a C-shaped canal in the mandibular second molar. MATERIALS AND METHODS: Cone-beam computed tomographic images of 264 patients were screened and examined. Axial sections of 1056 mandibular molars were evaluated to determine the number of roots. The interorifice distances from the distolingual canal to the distobuccal canal were also estimated. Using an image analysis program, the root canal curvature was calculated. Pearson's chi-square test, the paired t-test, one-way analysis of variance, and post-hoc analysis were performed. RESULTS: Distolingual roots were observed in 26.1% of the subjects. In cases where a distolingual root was observed in the mandibular molar, a significant difference was observed in the root canal curvature between the buccolingual and mesiodistal orientations. The maximum root canal curvature was most commonly observed in the mesiodistal orientation in the coronal portion, but in the apical portion, maximum root canal curvature was most often observed in the buccolingual orientation. CONCLUSION: The canal curvature of distolingual roots was found to be very complex, with a different direction in each portion. No correlation was found between the presence of a distolingual root in the mandibular first molar and the presence of a C-shaped canal in the mandibular second molar.

The effect of mineral trioxide aggregate on odontogenic differentiation in dental pulp stem cells.

INTRODUCTION: This study aimed to identify the early genetic changes related to odontogenic differentiation when mineral trioxide aggregate (MTA) is applied to dental pulp stem cells (DPSCs). METHODS: Odontogenic-differentiated cells (induced DPSCs) were obtained by culturing DPSCs in odontoinduction medium for 14 days. Thereafter, MTA in Teflon tubes was applied to the induced DPSCs and uninduced cells. Cells exposed to empty tubes were used as negative controls. The total RNA was extracted from the MTA treated and MTA untreated cells 1 and 3 days after tube application and assessed by microarray analysis. The key results were confirmed selectively by reverse-transcription polymerase chain reaction. We also performed a gene set enrichment analysis. RESULTS: In microarray analysis, although the expression levels of 460 genes were changed more than 2-fold in MTA-treated, uninduced DPSCs after 1 day, only 39 genes were altered in MTA-treated, induced DPSCs. In the odontoinduction medium-induced, MTA-treated DPCs, the value of correlation was 0.993 on 1 day and 0.986 on 3 day compared with 0.970 on 1 day and 0.975 on 3 day in the uninduced, MTA-treated DPSCs. Gene set enrichment analysis revealed that MTA significantly up-regulated gene sets involved in cell migration, the response to transforming growth factor ß1, and the inflammation pathway in the uninduced DPSCs, whereas in the induced DPSCs it only up-regulated genes involved in cell migration after 1 day. CONCLUSIONS: This result shows that MTA stimulates the odontogenic differentiation of DPSCs, and the effects of MTA are drastically increased in uninduced pulp cells compared with odontogenic-differentiated cells.

Analysis of gene expression during odontogenic differentiation of cultured human dental pulp cells.

OBJECTIVES: We analyzed gene-expression profiles after 14 day odontogenic induction of human dental pulp cells (DPCs) using a DNA microarray and sought candidate genes possibly associated with mineralization. MATERIALS AND METHODS: Induced human dental pulp cells were obtained by culturing DPCs in odontogenic induction medium (OM) for 14 day. Cells exposed to normal culture medium were used as controls. Total RNA was extracted from cells and analyzed by microarray analysis and the key results were confirmed selectively by reverse-transcriptase polymerase chain reaction (RT-PCR). We also performed a gene set enrichment analysis (GSEA) of the microarray data. RESULTS: Six hundred and five genes among the 47,320 probes on the BeadChip differed by a factor of more than two-fold in the induced cells. Of these, 217 genes were upregulated, and 388 were down-regulated. GSEA revealed that in the induced cells, genes implicated in Apoptosis and Signaling by wingless MMTV integration (Wnt) were significantly upregulated. CONCLUSIONS: Genes implicated in Apoptosis and Signaling by Wnt are highly connected to the differentiation of dental pulp cells into odontoblast.