Physicochemical Changes in Root-Canal Sealers under Thermal Challenge: A Comparative Analysis of Calcium Silicate- and Epoxy-Resin-Based Sealers.

INTRODUCTION: We compared the effects of heat on the physicochemical properties of recently developed calcium silicate-based sealers (CSBSs), including BioRoot Flow, BioRoot RCS, and AH Plus Bioceramic sealer, with those of the epoxy-resin-based sealer (ERBS) AH Plus. METHODS: The flow, film thickness, setting time, and solubility of sealers were evaluated at 37 °C and 100 °C using ISO 6876/2012. Furthermore, pH and calcium ion release were evaluated at these temperatures. In addition, the mass change in sealers at a high temperature was assessed via thermogravimetric analysis. Then, the chemical composition and components of the sealers were analyzed using a scanning electron microscope and Fourier-transform infrared spectroscopy (FTIR). RESULTS: BioRoot Flow, AH Plus Bioceramic, and AH Plus complied with ISO standards in terms of flow and film thickness, both before and after heat application. However, BioRoot RCS exhibited significantly increased film thickness at 100 °C. The setting times of all sealers were significantly reduced at 100 °C. The solubility of CSBS was >3%, exceeding the ISO 6876/2012 standard, both before and after heat exposure. Conversely, the solubility of AH Plus complied with the standard, regardless of the thermal condition. For 4 weeks, CSBS showed a significantly higher pH than AH Plus at both 37 °C and 100 °C. After heat treatment, calcium release decreased in Bioroot RCS and BioRoot Flow, while AH Plus showed no significant differences before and after treatment. However, CSBS consistently exhibited significantly higher calcium release than AH Plus at both temperatures. An FTIR analysis revealed that the chemical composition of the sealers did not change at the high temperature, whereas a thermogravimetric analysis demonstrated a >5% weight reduction in CSBS and a 0.005% weight reduction in AH Plus at 100 °C. CONCLUSIONS: BioRoot Flow, AH Plus Bioceramic, and AH Plus possess favorable physicochemical properties, which make them suitable for application under thermal conditions. At a high temperature, BioRoot RCS did not exhibit changes in its chemical composition. However, its film thickness was increased, and pH and solubility were reduced. Therefore, caution is needed when it is applied at high temperatures, such as during the warm obturation technique.

Predicting early endodontic treatment failure following primary root canal treatment.

BACKGROUND: Understanding when and why endodontic treatments fail could help clinicians make prognoses and thus improve treatment outcomes. This study was aimed to assess potential predictors of early endodontic treatment failure. We explored factors contributing to the failure of initial root canal treatment were explored, with a specific emphasis on evaluating the influence of the time elapsed since the initial treatment. METHODS: This retrospective cohort study enrolled 1262 patients who sought endodontic treatment at our department and 175 patients were included for analysis. Potential causes of endodontic treatment failure were investigated, such as inadequate obturation quality, inadequate coronal status, the presence of additional untreated canals, anatomical complexity, instrument separation, iatrogenic perforation, cracks, and endodontic-periodontal lesions. The patients were divided into "short-term" and "long-term" groups depending on the time that had passed since the initial treatment (i.e., < 5 and > 10 years, respectively). The causes of failure in the short-term and long-term group were analyzed and compared using logistic regression analyses. Subgroup analysis was performed according to the number of years since the initial treatment in the short-term group to further investigate the association between the time and cause of failure (i.e., < 1, 2, 3, and 4 years, respectively). RESULTS: Untreated additional canals were present in 21.7% of all cases, and in 36.9 and 6.4% of cases in the short-term and long-term groups, respectively. Multivariable analysis showed that the presence of untreated additional canals was significantly associated with short-term compared to long-term failure. Untreated additional canals were also associated with endodontic failure within 1, 2, 3, and 4 years. CONCLUSIONS: The presence of untreated additional canals was a predictor of endodontic failure within 5 years following initial root canal treatment. To optimize long-term prognosis, it is important to detect and treat all root canals during the initial treatment.

Biocompatible Properties and Mineralization Potential of Premixed Calcium Silicate-Based Cements and Fast-Set Calcium Silicate-Based Cements on Human Bone Marrow-Derived Mesenchymal Stem Cells.

Premixed calcium silicate-based cements (CSCs) and fast-set CSCs were developed for the convenience of retrograde filling during endodontic microsurgery. The aim of this study was to analyze the biocompatible properties and mineralization potential of premixed CSCs, such as Endocem MTA Premixed (EM Premixed) and EndoSequence BC RRM putty (EndoSequence), and fast-set RetroMTA on human bone marrow-derived mesenchymal stem cells (BMSCs) compared to ProRoot MTA. Using CCK-8, a significantly higher proliferation of BMSCs occurred only in the EM Premixed group on days 2 and 4 (p < 0.05). On day 6, the ProRoot MTA group had significantly higher cell proliferation than the control group (p < 0.05). Regardless of the experimental materials, all groups had complete cell migration by day 4. Alizarin Red-S staining and alkaline phosphatase assay demonstrated higher mineralization potential of all CSCs similar to ProRoot MTA (p < 0.05). The EndoSequence group showed more upregulation of SMAD1 and OSX gene expression than the other experimental groups (p < 0.05), and all experimental cements upregulated osteogenic gene expression more than the control group (p < 0.05). Therefore, using premixed CSCs and fast-set CSCs as retrograde filling cements may facilitate satisfactory biological responses and comparable osteogenic potential to ProRoot MTA.

Biological Characteristics and Odontogenic Differentiation Effects of Calcium Silicate-Based Pulp Capping Materials.

We compared calcium silicate-based pulp capping materials to conventional calcium hydroxide in terms of their biological properties and potential effects on odontogenic differentiation in human dental pulp stem cells (hDPSCs). We cultured hDPSCs on disks (7-mm diameter, 4-mm high) of ProRoot MTA (Dentsply Tulsa Dental Specialties), Biodentine (Septodont), TheraCal LC (Bisco), or Dycal (Dentsply Tulsa Dental Specialties). Cell viability was assessed with cell counting (CCK) and scanning electron microscopy (SEM). Odontogenic activity was assessed by measuring alkaline phosphatase (ALP) activity and gene expression (quantitative real-time PCR). CCK assays showed that Dycal reduced cell viability compared to the other materials (p < 0.05). SEM showed low and absent cell attachment on TheraCal LC and Dycal disks, respectively. hDPSCs exposed to TheraCal LC and Dycal showed higher ALP activity on day 6 than the control group (p < 0.05). The day-9 Runx2 expression was higher in the ProRoot MTA and TheraCal LC groups than in the control group (p < 0.05). On day 14, the ProRoot MTA group showed the highest dentin sialophosphoprotein levels (not significant; p > 0.05). In conclusion, various pulp capping materials, except Dycal, exhibited biological properties favorable to hDPSC viability. ProRoot MTA and TheraCal LC promoted higher Runx2 expression than Biodentine. Future studies should explore the odontogenic potential of pulp capping materials.

Comparison of the Effects of a Bioceramic and Conventional Resin-Based Sealers on Postoperative Pain after Nonsurgical Root Canal Treatment: A Randomized Controlled Clinical Study.

BACKGROUND: This clinical trial aimed to compare the effects of bioceramic sealer and resin-based sealer on the incidence and intensity of postoperative pain. METHODS: Patients with anterior teeth or premolars requiring root canal treatment were assigned to group 1 (n = 51). Those with molars requiring treatment were assigned to group 2 (n = 57). In groups 1En and 2En, root canals were obturated with Endoseal MTA using the single-cone technique. In groups 1AH and 2AH, the sealer used was AH Plus with the continuous wave technique. On the day of canal filling, each patient was instructed to indicate their pain intensity over the 7 day postoperative period, at rest and, while biting, using a visual analog scale. RESULTS: There was no significant difference in the incidence or intensity of postoperative pain between the Endoseal MTA and AH Plus groups during the 7 day postoperative period (p > 0.05). Less time was needed to seal the root canals with Endoseal MTA, especially in group 2 (p < 0.05). CONCLUSIONS: Endoseal MTA and AH Plus had similar effects on the incidence and intensity of postoperative pain. The obturation time was shorter when using Endoseal MTA compared to AH Plus.

Effects of Ultrasonic Activation on Root Canal Filling Quality of Single-Cone Obturation with Calcium Silicate-Based Sealer.

BACKGROUND: We evaluated the effects of ultrasonic activation on root canal filling quality of the single-cone (SC) obturation technique with calcium silicate sealers and gutta percha cones. METHODS: Thirty-six human single-rooted premolars were obturated with gutta percha and sealer. For the continuous wave (CW) group (n = 12), AH Plus with a continuous wave technique was used. The SC group (n = 12) received EndoSequence BC sealer with a single-cone technique. The SCU (SC with the addition of ultrasonic activation) group (n = 12) received the same treatment. Micro-computed tomography was used to scan the teeth, and the void volume within the root canal was evaluated at the apical, middle, and coronal levels. Then cross-sections were observed under a light microscope and scanning electron microscope (SEM). RESULTS: Void volume was significantly lower in the SCU group than in the CW and SC groups. There were no statistically significant differences between the CW and SC groups. The SCU group had fewer voids than the CW and SC groups in the coronal and middle third areas. Specimens showed no apparent gaps or voids in any group. SEM images revealed both gap-free and gap-containing regions at different levels in all groups. CONCLUSIONS: Single-cone obturation with calcium silicate-based sealers might obtain enhanced filling quality when used with ultrasonic activation.

Influence of Preoperative Mechanical Allodynia on Predicting Postoperative Pain after Root Canal Treatment: A Prospective Clinical Study.

INTRODUCTION: Odontogenic pain can manifest as pulpal pain, periapical pain (mechanical allodynia), or both. This study aimed to assess the changes in the intensity of mechanical allodynia (MA) and to identify predictors of postoperative pain after root canal treatment (RCT). METHODS: In total, 579 consecutive patients who required RCT were enrolled; we included patients with asymptomatic pulpal diagnoses to avoid any effects of preoperative spontaneous pain on postoperative pain and to evaluate MA independently. Using a visual analog scale (VAS), patients separately indicated the intensity of spontaneous pain, tenderness to percussion, and pain on biting; these measurements were performed before treatment (preoperative pain), at the beginning of each visit (postpreparation pain), and daily for 1 week after RCT (postobturation pain). For analytical purposes, patients were subdivided into 2 groups based on the intensity of preoperative MA (none to mild [VAS <4] or moderate to severe [VAS ≥4]) to evaluate changes in MA and predictive factors of moderate to severe postoperative pain. A generalized estimating equation, repeated-measures analysis of variance, and logistic regression analysis were used. RESULTS: Although the intensity of MA was significantly higher in the moderate to severe group after the initiation of RCT (P < .05), 93% of them experienced alleviation in MA, and 30% of patients in the none to mild group experienced an increase in MA. After adjusting for clinical variables, moderate to severe preoperative MA and the presence of necrotic pulp were significantly correlated with moderate to severe postoperative pain with an odds ratio of 4.107 and 0.286, respectively. CONCLUSIONS: Moderate to severe preoperative MA was a predictive factor of postoperative pain in patients undergoing RCT.

Comparison of Obturation Quality between Calcium Silicate-Based Sealers and Resin-Based Sealers for Endodontic Re-treatment.

BACKGROUND: The objective of this micro-computed tomography (micro-CT)-based study was to compare the filling quality of endodontic treatment and endodontic Re-treatment between two sealers with matched obturation techniques: calcium silicate-based sealer (Endoseal TCS) with a single-cone technique (SCT) and resin-based sealer (AH Plus) with a continuous wave technique (CWT). METHODS: Forty maxillary premolars were selected and assigned into four groups, according to the obturation methods of the first endodontic treatment and Re-treatment (n = 10). The AP/AP group was first treated with AH Plus/CWT, then re-treated with AH Plus/CWT. The AP/ET group was first treated with AH Plus/CWT, then re-treated with Endoseal TCS/SCT. The ET/AP group was first treated with Endoseal TCS/SCT, then re-treated with AH Plus/CWT, and the ET/ET group was first treated with Endoseal TCS/SCT, then re-treated with Endoseal TCS/SCT. The specimens were scanned using micro-CT at three time points: after the first endodontic treatment, after gutta-percha (GP) cone removal, and after Re-treatment. The void volume of root canal obturation and the volume of the remaining filling materials were calculated. Data were analyzed using Student's t-tests and ANOVA. RESULTS: The Endoseal TCS groups (ET/AP and ET/ET) showed a lower percentage of voids than the AH plus groups (AP/AP and AP/ET) on the whole canal and the apical third, after first obturation (p < 0.05). The AH plus group showed significantly fewer remnants than the Endoseal TCS group after GP removal (p < 0.05). Re-treated canals and initially treated canals had similar void volumes (p > 0.05). There was no significant difference in void volume after Re-treatment, regardless of whether the same or different sealers were used for the first treatment and Re-treatment (p < 0.05). CONCLUSIONS: Endoseal TCS sealer and AH Plus sealer had a similar Re-treatment efficacy, regardless of which sealer was used in the previous treatment.

Biocompatibility and Bioactivity of Set Direct Pulp Capping Materials on Human Dental Pulp Stem Cells.

In this study, we assessed the biocompatibility and bioactivity of various pulp capping materials-ProRoot MTA (Dentsply Tulsa Dental Specialties), Biodentine (Septodont), TheraCal LC (Bisco), and Dycal (Dentsply Caulk)-on human dental pulp stem cells (hDPSCs). Experimental disks (diameter, 7 mm; height, 4 mm) were stored in a humified incubator at 37 °C for 48 h. Then, the pulp capping materials were tested for cytotoxic effects by methyl-thiazoldiphenyl-tetrazolium and scratch wound healing assays, and for mineralization potential by Alizarin red S (ARS) staining assay and alkaline phosphatase enzyme (ALP) activity. Cell viability and cell migration did not significantly differ between ProRoot MTA, Biodentine, and control (p > 0.05). TheraCal LC exhibited slower cell migration on days 2-4 compared to control (p < 0.05), and Dycal showed no cell migration. ALP activity was highest with Biodentine on days 10 and 14, and was lowered with TheraCal LC and Dycal (p < 0.05). In the ARS assay, hDPSCs grown in ProRoot MTA and TheraCal LC eluates showed significantly increased mineralized nodule formation on day 21 compared to Biodentine, Dycal, and control (p < 0.05). These findings indicate that ProRoot MTA, Biodentine, and TheraCal LC exhibit better biocompatibility and bioactivity than Dycal.

Pre-application of dentin bonding agent prevents discoloration caused by mineral trioxide aggregate.

BACKGROUND: To evaluate tooth discoloration by newly developed calcium silicate-based materials, and to examine the pre-application of dentin bonding agent (DBA) for preventing discoloration caused by mineral trioxide aggregate (MTA). METHODS: The roots of 50 premolars were randomly divided into five groups (n = 10) and cavities were prepared from resected root surfaces. MTA was placed in the cavities of teeth belonging to the ProRoot MTA (MTA) and RetroMTA (RMTA) groups. For teeth belonging to the ProRoot + DBA (MTA-B) and RetroMTA + DBA (RMTA-B) groups, DBA was first applied to the cavities prior to the addition of MTA. Teeth in the control group were restored with composite resin only (i.e., without MTA). After 12 weeks, MTA was removed from the MTA and RMTA groups and bleaching agents were applied for 3 additional weeks. Color assessments were recorded at baseline, and 1, 4, and 12 weeks, as well as after bleaching. A one-way ANOVA was performed to assess the differences between the two types of MTAs and color changes following DBA pre-application in each MTA group. A p-value of < 0.05 was considered indicative of statistical significance. RESULTS: Following 12 weeks of MTA treatment, there was a significant difference between the discoloration in the MTA and RMTA groups (p < 0.05). However, no significant difference was observed between the RMTA and RMTA-B groups (p > 0.05). Following bleaching, the color changes (ΔE values) of the MTA group were not significantly different from those of the MTA-B group (p > 0.05). The difference of ΔE between the RMTA group after internal bleaching and the RMTA-B group was also not significant (p > 0.05). CONCLUSIONS: RetroMTA caused significantly less discoloration than ProRoot MTA. Pre-application of DBA reduced discoloration caused by ProRoot MTA. MTA discoloration was improved equally well between DBA pre-application and post-bleaching.

Clinical Factors Associated with Apical Periodontitis Visible on Cone-beam Computed Tomography but Missed with Periapical Radiographs: A Retrospective Clinical Study.

INTRODUCTION: Cone-beam computed tomographic (CBCT) imaging is useful in detecting apical periodontitis, which is often missed in periapical (PA) radiographs. This study aimed to identify preoperative predictors correlated with the presence of apical periodontitis visible only in CBCT images and to investigate the important characteristics of such lesions. METHODS: In total, 332 consecutive patients with both PA radiographs and CBCT images were enrolled in this study. The patients' clinical charts were reviewed retrospectively to collect information regarding their symptoms and diagnoses. Periapical lesions were assessed using a modified CBCT PA index by 2 endodontists. Patient-related factors (age, sex, and symptoms) and tooth-related factors (tooth type, location, pulp status, and pulpal diagnosis) were assessed to determine their relationships with the presence of apical periodontitis visible only in CBCT images. RESULTS: Apical periodontitis was detected in 24.6% and 35.5% of untreated teeth by PA radiographs and CBCT images, respectively. In a multivariate logistic regression analysis, pulp necrosis was significantly correlated with the presence of apical periodontitis visible only in CBCT images (odds ratio = 5.401; 95% confidence interval, 1.911-15.265; P = .001); the involvement of molars showed borderline nonsignificant correlation (odds ratio = 2.843; 95% confidence interval, 0.990-8.164; P = .052). Lesion sizes smaller than 2 mm in diameter and the involvement of molars were significant factors of lesions visible only in CBCT images (P < .05). CONCLUSIONS: Pulp necrosis was a preoperative predictor of apical periodontitis visible only in CBCT images. This research could provide a proper indication for CBCT imaging at diagnostic stages.

Frequency of non-single canals in mandibular premolars and correlations with other anatomical variants: an in vivo cone beam computed tomography study.

BACKGROUND: A knowledge regarding anatomical variants is important to achieve success in endodontic treatment. Root canal treatment of mandibular first premolars (PM1 s) is challenging due to the existence of numerous variations in canal configurations, including a C-shaped variant. We aim to determine the frequency and morphologic characteristics of non-single canals of mandibular first (PM1 s) and second (PM2 s) premolars in a Korean population using cone beam computed tomography (CBCT) and to evaluate correlations between non-single canals of PM1 s and other anatomical variants, such as distolingual roots (DLRs) in mandibular first molars (M1 s) and C-shaped canals in mandibular second molars (M2 s). METHODS: A total of 971 PM1 s and 997 PM2 s from 500 patients were examined in vivo by CBCT. Root canal configurations and C-shaped canals were determined in accordance with the Vertucci classification and Fan classification, respectively. The correlation between non-single canals in PM1 s and DLRs in M1 s was evaluated using logistic regression analysis. RESULTS: PM2 s typically had one root (99.89%) with one canal (98.4%). Among PM1 s with non-single canals (21.2%), Vertucci type V (10.9%) and C-shaped (3.7%) canals were prevalent. Among C-shaped PM1 canals, the majority were Vertucci type V (77.8%); a C-shaped configuration (C2) was predominant mostly at the middle and/or apical third of the root. After adjusting for other variables (i.e., sex, age, and side), C-shaped canals in PM1 s was significantly correlated with the presence of DLRs in M1 s (odds ratio = 2.616; 95% confidence interval, 1.257-5.443; p = 0.010). CONCLUSIONS: The presence of C-shaped PM1 canals was positively related to the presence of DLRs in M1 s. Although C-shaped canals in PM1 s are difficult to distinguish, this finding could aid clinicians in predicting C-shaped canal configurations in PM1 s of patients who exhibit DLRs in M1 s.

The Penetration Ability of Calcium Silicate Root Canal Sealers into Dentinal Tubules Compared to Conventional Resin-Based Sealer: A Confocal Laser Scanning Microscopy Study.

The purpose of this study was to compare the penetration ability of calcium silicate root canal sealers and conventional resin-based sealer using confocal laser scanning microscopy (CLSM). A total of 60 recently extracted single-rooted human premolars were used in this study. The root canals were prepared to a size 40/0.06 taper with ProFile rotary instruments and irrigated with NaOCl and EDTA. After drying all canals, the specimens were randomly divided into three experimental groups (n = 20): Group 1, gutta-percha (GP)/AH Plus with continuous wave compaction; group 2, GP/BioRoot RCS with a single-cone technique; and group 3, GP/Endoseal MTA with a single-cone technique. All experimental samples were sectioned perpendicular to their long axis using a low-speed diamond wheel at the apical, middle, and coronal third levels. The penetration abilities of all samples were evaluated using CLSM. A Kruskal⁻Wallis analysis and a series of Mann⁻Whitney U post hoc tests were performed. A higher intensity level was found in the coronal area and a lower intensity level in the apical area in all the experimental groups. The AH Plus group showed higher sum fluorescence intensity in the apical and coronal thirds compared with the BioRoot RCS and Endoseal MTA groups, whereas the BioRoot RCS group showed a higher intensity level in the middle third, similar to the AH Plus group. The maximum sealer penetration depth was low in the apical area and high in the coronal area in the AH Plus and Endoseal MTA groups. In the BioRoot RCS group, maximum sealer penetration was observed in the middle third. In conclusion, there were significant differences in sealer penetration pattern and distance according to the root level and sealer type.

Predicting neo-adjuvant chemotherapy response and progression-free survival of locally advanced breast cancer using textural features of intratumoral heterogeneity on F-18 FDG PET/CT and diffusion-weighted MR imaging.

Predicting response to neo-adjuvant chemotherapy (NAC) and survival in locally advanced breast cancer (LABC) is important. This study investigated the prognostic value of tumor heterogeneity evaluated with textural analysis through F-18 fluorodeoxyglucose (FDG) positron emission tomography (PET) and diffusion-weighted imaging (DWI). We enrolled 83 patients with LABC who had completed NAC and curative surgery. Tumor texture indices from pretreatment FDG PET and DWI were extracted from histogram analysis and 7 different parent matrices: co-occurrence matrix, the voxel-alignment matrix, neighborhood intensity difference matrix, intensity size-zone matrix (ISZM), normalized gray-level co-occurrence matrix (NGLCM), neighboring gray-level dependence matrix (NGLDM), and texture spectrum matrix. The predictive values of textural features were tested regarding both pathologic NAC response and progression-free survival. Among 83 patients, 46 were pathologic responders, while 37 were nonresponders. The PET texture indices from 7 parent matrices, DWI texture indices from histogram, and 1 parent matrix (NGLCM) showed significant differences according to NAC response. On multivariable analysis, number nonuniformity of PET extracted from the NGLDM was an independent predictor of pathologic response (P = .009). During a median follow-up period of 17.3 months, 14 patients experienced recurrence. High-intensity zone emphasis (HIZE) and high-intensity short-zone emphasis (HISZE) from PET extracted from ISZM were significant textural predictors (P = .011 and P = .033). On Cox regression analysis, only HIZE was a significant predictor of recurrence (P = .027), while HISZE showed borderline significance (P = .107). Tumor texture indices are useful for NAC response prediction in LABC. Moreover, PET texture indices can help to predict disease recurrence.

Prognostic value of diffuse splenic FDG uptake on PET/CT in patients with gastric cancer.

BACKGROUND: This study investigated the prognostic value of diffuse splenic uptake on F-18 fluorodeoxyglucose (FDG) positron emission tomography (PET)/computed tomography (CT) in gastric cancer (GC) patients. METHODS: A total of 134 pathology confirmed GC patients who underwent PET/CT for staging work-ups were enrolled. The maximal standardized uptake value (SUVmax) of primary tumor (Tmax), spleen (Smax), and spleen to liver uptake ratio (SLR) were measured. The prognostic value of PET-measured parameters in GC patients for predicting recurrence-free survival (RFS) and overall survival (OS) were assessed. And the relationships of the parameters with hematological and inflammatory parameters were also investigated. RESULTS: During follow-up period, 19 patients (14.1%) had disease recurrence and 12 (8.9%) died from GC. In univariate analysis, hematocrit (p<0.001 and p = 0.002), neutrophil to lymphocyte ratio (NLR; p = 0.021 and p = 0.040), AJCC staging (p<0.001 and p<0.001), adjuvant chemotherapy (p<0.001 and p<0.001), Tmax (p = 0.004 and p = 0.005), and SLR (p = 0.005 and p = 0.016) were significant prognostic factors for RFS and OS, whereas platelet to lymphocyte ratio (PLR; p = 0.034) was a significant prognostic factor for RFS. In multivariate analysis, only SLR was an independent prognostic factor for RFS (p = 0.018, adjusted HR = 3.011, 95% CI = 1.207-7.511). SLR were significantly associated with serum hematocrit level (r = -0.256, p = 0.002), PLR (r = 0.362, p = 0.001), and Tmax (r = 0.280, p = 0.001). CONCLUSION: Diffuse splenic uptake on FDG PET/CT was correlated with the level of hematological and inflammatory parameters and was an independent predictor for RFS in GC.

Analysis of Cause of Endodontic Failure of C-Shaped Root Canals.

The purpose of this study was to analyze various characteristics and classification of C-shaped root canals and evaluate the causes of endodontic failure of C-shaped root canals by examining the resected root surface with an endodontic microscope and a scanning electron microscope (SEM). Forty-two teeth with C-shaped root canals were included in this study and had undergone intentional replantation surgery. Before surgery, periapical radiography and cone-beam computed tomography were taken. The root canal configuration was analyzed and classified according to Melton's classification at coronal and apical level. After injection of 1 : 100,000 epinephrine with 2% lidocaine, the tooth was carefully extracted. After the root-end resection, the resected root surface was examined using an operating microscope and SEM. Mandibular second molars were most frequently involved teeth (90.4%). The most frequently observed root canal configurations were C1 at the coronal level (45.2%) and C3 at the apical 3 mm level (45.2%). The most common cause of failure for a C-shaped root canal treatment was a leaky canal (45.2%), followed by an isthmus (23.8%), missing canal, overfilling, and iatrogenic problems. In conclusion, C-shaped root canals were most frequently found in mandibular second molars. The most common cause of failure was a leaky canal and isthmus.

Morphological Characteristics and Classification of Mandibular First Molars Having 2 Distal Roots or Canals: 3-Dimensional Biometric Analysis Using Cone-beam Computed Tomography in a Korean Population.

INTRODUCTION: The aim of this study was to determine the morphologic characteristics of mandibular first molars having 2 canals in distal roots. Interorifice distance, buccal bone thickness, and root curvature were evaluated using cone-beam computed tomography images in a Korean population. METHODS: In total, 1958 mandibular first molars were evaluated in axial, coronal, sagittal, and paraxial planes. Distal roots having 2 canals were classified according to their root and canal shapes (2 roots, 2 canals [2R2C]; 1 root, 2 canals with 2 apical foramina [1R2C(2-2)]; and 1 root, 2 canals with 1 apical foramen [1R2C(2-1)]). The distances between orifices and the distance from the apex to the buccal bone plate were measured for each root canal shape (2R2C, 1R2C[2-2], and 1R2C[2-1]). The curvature of distolingual (DL) roots was classified according to severity using 3-dimensional reconstructed images, and the direction of curvature was determined. The relationships of these characteristics to sex and side were evaluated. RESULTS: The prevalences of 2R2C, 1R2C(2-2), and 1R2C(2-1) were 25.89%, 10.32%, and 14.15%, respectively. The distances between distobuccal (DB) and DL orifices were 3.77 ± 0.74 mm for 2R2C, 3.02 ± 0.65 mm for 1R2C(2-2), and 2.44 ± 0.64 mm for 1R2C(2-1). The distances from the buccal plate to the DB canal were 3.84 ± 1.35 mm for 2R2C, 5.33 ± 1.41 mm for 1R2C(2-2), and 5.96 ± 1.63 mm for 1R2C(2-1). The distance from the buccal plate to the DL canal was 9.85 ± 1.46 mm for 2R2C, and 8.28 ± 1.50 mm for 1R2C(2-2). All distances differed significantly according to root canal configurations, and all were greater in men than women (P < .05), except for the DB-DL orifice distance in 1R2C(2-2) and the DB to buccal cortical plate distance in all root configurations (P > .05). No significant difference between the left and right sides was found (P > .05). The prevalence of most severely curved DL roots (type III) was 62.92%, and the direction was commonly toward the buccal side (69.03%). CONCLUSIONS: The prevalence of mandibular first molars having 2 canals in distal roots was more than 50% in a Korean population. Interorifice distances between DB and DL canals and distances from the apex to the buccal cortical plate differed according to root and canal numbers and shapes.

Enhanced Application of 18F-FDG PET/CT in Bladder Cancer by Adding Early Dynamic Acquisition to a Standard Delayed PET Protocol.

PURPOSE: We investigated the value of early dynamic (ED) PET for the detection and characterization of bladder cancer. METHODS: Fifty-two bladder cancer patients were prospectively enrolled. The study protocol was composed of ED, whole-body (WB, 60 minutes after injection), and additional delayed (AD, 120 minutes after injection) PET acquisition. Early dynamic PET was acquired for 10 minutes and reconstructed as 5 frames at 2-minute intervals. A focal radiotracer accumulation confined to the bladder wall was considered as PET positive and referred for further quantitative measurement. SUVmax on ED (SUVmax, SUVmax, SUVmax, SUVmax, and SUVmax for 5 frames), WB (SUVmax), and AD PET (SUVmax) were measured. PET results were correlated with bladder cancer pathology variables. RESULTS: The sensitivities of ED, WB, and AD PET for bladder cancer were 84.6%, 57.7%, and 61.2%, respectively. The sensitivity of ED PET was significantly higher than that of WB (P = 0.002) and AD PET (P = 0.008). On ED PET, SUVmax was significantly correlated with muscle invasiveness, histological grade, and pathological tumor size (P = 0.018, P = 0.030, and P = 0.030). On WB and AD PET, only pathological tumor size showed significant positive correlation with SUVmax and SUVmax (P = 0.043 and P = 0.007). CONCLUSIONS: Early dynamic PET can help to detect and characterize bladder cancer.

Glucose metabolism of visceral adipose tissue measured by 18F-FDG PET/CT is related to the presence of colonic adenoma.

This study investigated the relationships between the area and metabolic activity of adipose tissue and the presence of colorectal adenoma (CRA). Our institutional review board approved the study and waived informed consent. A total of 212 subjects who underwent fluorine 18 fluorodeoxyglucose (FDG) positron emission tomography (PET)/computed tomography (CT) and colonoscopy for routine health check-ups were enrolled. The volumetric parameters of areas of visceral (VATav), subcutaneous (SATav), and total adipose tissue (TATav) and calculated visceral-to-subcutaneous adipose tissue ratio (VSR) and visceral-to-total adipose tissue ratio (VAR) were considered. Metabolic parameters of standardized uptake value (SUV) of visceral (vcSUVmax, vcSUVmean), subcutaneous (scSUVmax, scSUVmean), and calculated visceral-to-subcutaneous adipose tissue ratio (VSRmax, VSRmean) were considered. Anthropometric data of height, weight, body mass index (BMI), waist circumference (WC), body fat mass (BFM), skeletal muscle mass (SMM), and diverse laboratory data were also considered as variables. Sixty-six subjects were placed in the CRA group and 146 subjects in the non-CRA group. The presence of CRA was significantly correlated with older age (P  =  .001), male sex (P  =  .041), higher BMI (P  =  .004), higher WC (P  =  .001), higher BFM (P  =  .024), higher VATav (P < .001), higher TATav (P  =  .004), higher VSR (P < .001), higher VAR (P < .001), lower vcSUVmax (P  =  .002), lower vcSUVmean (P < .001), and lower VSRmean (P  =  .002). On multiple regression analysis, vcSUVmax and vcSUVmean were independently associated with the presence of CRA (P  =  .009 and P  =  .045). Lower glucose metabolism of visceral adipose tissue was related to the presence of CRA. Our findings identify the value of visceral metabolic dysfunction as a potential surrogate marker of elevated risk for CRA.

Cracked Teeth: Distribution, Characteristics, and Survival after Root Canal Treatment.

INTRODUCTION: The aims of this study were to analyze the distribution and characteristic features of cracked teeth and to evaluate the outcome of root canal treatments (RCTs) for cracked teeth. The prognostic factors for tooth survival were investigated. METHODS: Over the 5-year study period, 175 teeth were identified as having cracks. Data were collected regarding the patients' age, sex, tooth type, location and direction of cracks, probing depth, pulp vitality, type of restoration, cavity classification, opposing teeth, and previous endodontic treatment history. Cracked teeth were managed via various treatment methods, and the 2-year survival rate after RCT was analyzed using the Kaplan-Meier method in which significance was identified using the log-rank test. Possible prognostic factors were investigated using Cox multivariate proportional hazards modeling. RESULTS: One hundred seventy-five teeth were diagnosed with cracks. Most of the patients were aged 50-60 years (32.0%) or over 60 (32.6%). The lower second molar was the most frequently (25.1%) affected tooth. Intact teeth (34.3%) or teeth with class I cavity restorations (32.0%) exhibited a higher incidence of cracks. The 2-year survival rate of 88 cracked teeth after RCT was 90.0%. A probing depth of more than 6 mm was a significant prognostic factor for the survival of cracked teeth restored via RCT. The survival rate of root-filled cracked teeth with a probing depth of more than 6 mm was 74.1%, which is significantly lower than that of teeth with probing depths of less than 6 mm (96.8%) (P = .003). CONCLUSIONS: Cracks were commonly found in lower second molars and intact teeth. RCT was a reliable treatment for cracked teeth with a 2-year survival rate of 90.0%. Deep probing depths were found to be a significant clinical factor for the survival of cracked teeth treated with RCT.