Incidence and Risk Factors of Deep Venous Thrombosis in Asymptomatic Iliac Vein Compression: A Prospective Cohort Study.

BACKGROUND: Deep vein thrombosis (DVT) may be associated with iliac vein compression. Up to now, the majority of data has come from a retrospective study about the correlation between DVT and iliac vein compression. This prospective study was to determine the incidence of DVT in individuals with iliac vein compression and identify risk factors predictive of DVT. METHODS: A total of 500 volunteers without symptoms of venous diseases of lower extremities and overt risk factors of deep venous thrombosis between October 2011 and September 2012 in Shijitan Hospital were enrolled in this cohort study. All the participants underwent contrast-enhanced abdominal computed tomography (CT) to evaluate iliac vein compression. Baseline demographic information and degree of iliac vein compression were collected. They were categorized into ≥50% or <50% iliac vein compression group. Ultrasound examination was performed to screen DVT at the time of CT examination and 3, 6, 9, and 12 months after the examination. Primary event was DVT of ipsilateral lower extremity. Correlation between DVT and iliac vein compression was estimated by multivariate Logistic regression after adjusting for age, gender, malignancy, surgery/immobilization, chemotherapy/hormonal therapy, and pregnancy. RESULTS: In 500 volunteers, 8.8% (44) had ≥50% iliac vein compression and 91.2% (456) had <50% iliac vein compression. Ipsilateral DVT occurred in six volunteers including two in iliofemoral vein, two in popliteal vein, and two in calf vein within 1 year. Univariate analysis showed that the incidence of DVT was 6.8% in ≥50% compression group, significantly higher than that in <50% compression group (0.7%) (χ2 = 12.84, P = 0.01). Patients with malignancy had significantly higher incidence of DVT than those without malignancy (χ2 = 69.60,P< 0.01). Multivariate Logistic regression indicated that iliac vein compression and malignancy were independent risk factors of DVT. After adjustment for malignancy, patients with ≥50% iliac vein compression had 10-fold increased risk of developing DVT (adjusted relative risk [RR] = 10.162, 95% confidence interval [CI]: 1.149-89.865, P = 0.037). In subgroup analysis, patients with malignancy and ≥50% iliac vein compression had 12-fold increased the risk of DVT than those without malignance and ≥50% compression (RR = 12.389, 95% CI: 2.327-65.957, P = 0.003). CONCLUSIONS: Iliac vein compression is common, but the incidence of DVT is low. Only individuals with ≥50% iliac vein compression or compression combined with other risk factors might have significantly increased the risk of DVT. Further study is recommended to improve prevention strategies for DVT in significant iliac vein compression.

Management of Apical Periodontitis: Healing of Post-treatment Periapical Lesions Present 1 Year after Endodontic Treatment.

INTRODUCTION: Post-treatment periapical lesions present 1 year after treatment may heal during the second year or later. The aim of this study was to assess second-year volumetric changes in post-treatment periapical radiolucencies detected 1 year after treatment. METHODS: Post-treatment periapical radiolucencies were detected on cone-beam computed tomographic (CBCT) scans obtained from 93 single-rooted teeth 1 year after endodontic treatment. The outcome of these teeth was evaluated 2 years after treatment. Two examiners independently measured the volume of the radiolucencies on CBCT images twice. A Wilcoxon signed rank test was used to assess the 1- and 2-year post-treatment volumes. RESULTS: The intraclass correlation coefficients for the CBCT volumetric measurements were 0.971 and 0.998 for the 2 examiners, and the interexaminer correlation coefficient was 0.998. Of the 93 teeth with post-treatment radiolucencies at 1 year, 61were examined at the second-year evaluation. The overall size of the radiolucencies significantly decreased during the second year (P = .01); the volume decreased in 38 teeth (63%), remained unchanged in 20 (33%), and increased in 2 (3%). CONCLUSIONS: The volume of post-treatment periapical radiolucencies detected 1 year after treatment was significantly reduced after the second year in 63% of teeth.

Effect of a two-step placement procedure on the dislocation resistance of a methacrylate resin-based root canal sealer: a proof of concept.

PURPOSE: To investigate whether the placement of a methacrylate root canal sealer or a conventional epoxy root canal sealer in two steps increases their dislocation resistance when compared to a one-step placement procedure. MATERIALS AND METHODS: Eighty single-rooted teeth were randomly allocated to 4 groups (n=20). All canals were instrumented to size 40, 0.06 taper and irrigated according to a standardized protocol. Root canal filling was conducted as follows: group 1: methacrylate sealer placed in two steps; group 2: methacrylate sealer placed in one step; group 3: epoxy sealer placed in two steps; group 4: epoxy sealer placed in one step. After setting, thin slices at different root levels were obtained and submitted to push-out testing. RESULTS were analyzed with non-parametric tests to compare the two-step procedures to their one-step counterparts. Failure modes were determined by stereomicroscopy. Random untested methacrylate sealer specimens were also examined with scanning electron microscopy. RESULTS: At each root level, dislocation resistance was significantly higher for the two-step procedure than for the one-step procedure using the methacrylate sealer (p=0.003, p=0.005, p<0.001) but not the epoxy sealer (p=0.83, p=0.1, p=0.06). Among root levels, there were no significant differences in dislocation resistance in the methacrylate sealer two-step group, while all other groups showed differences. CONCLUSION: A two-step placement procedure resulted in significantly higher dislocation resistance for the methacrylate sealer but not for the epoxy sealer.

The validity of cone-beam computed tomography in measuring root canal length using a gold standard.

INTRODUCTION: The distance between a coronal reference point and the major apical foramen is important for working length determination. The aim of this in vitro study was to determine the accuracy of root canal length measurements performed with cone-beam computed tomographic (CBCT) scans using a gold standard. METHODS: A total of 162 teeth (198 root canals) in 16 dry human dentulous mandibles were scanned using a 3DX-Accuitomo CBCT scanner (Morita 3DX; J Morita Mfg Corp, Kyoto, Japan). The root canal length was measured with CBCT data. All teeth were extracted atraumatically and endodontically accessed; the root canal length was measured blindly using a #10 K-file (Dentsply Maillefer, Ballaigues, Switzerland) and served as the gold standard. RESULTS: The mean absolute difference of the CBCT-based root canal length from the gold standard was 0.46 mm (95% confidence interval, 0.41-0.50 mm). Only in 9 of 198 (4.5%) roots did the difference between the CBCT-based root canal length and the gold standard exceed 1 mm. CONCLUSIONS: CBCT-based root canal length measurements are accurate and reliable when compared with a gold standard.

Radiographic healing after a root canal treatment performed in single-rooted teeth with and without ultrasonic activation of the irrigant: a randomized controlled trial.

INTRODUCTION: The aim of this study was to compare the outcome of a root canal treatment with and without additional ultrasonic activation of the irrigant. METHODS: Single-rooted teeth with radiographic evidence of periapical bone loss were randomly assigned to 2 treatment groups. In both groups syringe irrigation was performed, and in one group the irrigant was also activated by ultrasound. Ten to 19 months after treatment, the teeth were examined by using periapical radiography (PA) and cone-beam computed tomography (CBCT). Area and volume of the periapical lesions were measured, and the outcome was presented in 4 categories: absence, reduction or enlargement of the radiolucency, or uncertain. Lesions were classified as reduced or enlarged when the change in size of the radiolucency was 20% or more. RESULTS: The recall rate was 82%, and 84 teeth were analyzed. CBCT detected significantly more post-treatment lesions than PA (P = .038), but the percentages of absence and reduction of the radiolucency together revealed by CBCT and PA were similar (P = .383). The CBCT results showed that absence of the radiolucency was observed in 16 of 84 teeth (19%) and reduction of the radiolucency in 61 of 84 teeth (72.6%), but there was no significant difference between the results of the 2 groups (P = .470). Absence and reduction of the radiolucency together were observed in the ultrasonic group in 39 of 41 teeth (95.1%) and in the syringe group in 38 of 43 teeth (88.4%). CONCLUSIONS: Root canal treatments with and without additional ultrasonic activation of the irrigant contributed equally to periapical healing.

Area and 3-dimensional volumetric changes of periapical lesions after root canal treatments.

INTRODUCTION: This study compared the changes in size of periapical lesions after root canal treatment as revealed by periapical radiography (PA) and cone-beam computed tomography (CBCT) imaging using area and 3-dimensional volumetric measurements and assessed the outcome of the treatments based on these parameters. METHODS: Both PA and CBCT scans were taken preoperatively and at recall. In total, 50 teeth (71 roots) with evidence of periapical bone loss on both PA and CBCT images were endodontically treated and followed for 10-37 months. The area and volume of periapical lesions were measured, and changes were presented in the following 4 categories: lesion undetected, lesion reduced in size, lesion unchanged, or lesion enlarged. The McNemar and chi-square tests were used to compare the lesion changes determined by CBCT imaging and PA. RESULTS: The 4-category diagnosis made using both methods were in agreement in 39 of 71 (54.9%) roots, whereas disagreement was observed in 32 of 71 (45.1%) roots (P < .001). At recall, lesion was absent in 11 of 71 (15.5%) roots on CBCT scans and 32 of 71 (45.1%) roots on PA (P < .001). When success was defined as the absence of a lesion or a reduction in size of a lesion, 55 (77.5%) roots on CBCT imaging showed success and 63 (88.7%) roots on PA (P = .073). CONCLUSIONS: Changes in lesion size after root canal treatment determined with 3-dimensional volumetric CBCT data and 2-dimensional PA data are different. The outcome of root canal treatments determined with PA could be untrue.

The incidence of root microcracks caused by 3 different single-file systems versus the ProTaper system.

INTRODUCTION: The aim of this study was to compare the incidence of root cracks observed at the apical root surface and/or in the canal wall after canal instrumentation with 3 single-file systems and the ProTaper system (Dentsply Maillefer, Ballaigues, Switzerland). METHODS: One hundred mandibular incisors were selected. Twenty control teeth were coronally flared with Gates-Glidden drills (Dentsply Maillefer). No further preparation was made. The other 80 teeth were mounted in resin blocks with simulated periodontal ligaments, and the apex was exposed. They were divided into 4 experimental groups (n = 20); the root canals were first coronally flared with Gates-Glidden drills and then instrumented to the full working length with the ProTaper, OneShape (Micro-Mega, Besancon, France), Reciproc (VDW, Munich, Germany), or the Self-Adjusting File (ReDent-Nova, Ra'anana, Israel). The apical root surface and horizontal sections 2, 4, and 6 mm from the apex were observed under a microscope. The presence of cracks was noted. The chi-square test was performed to compare the appearance of cracked roots between the experimental groups. RESULTS: No cracks were found in the control teeth and teeth instrumented with the Self-Adjusting File. Cracks were found in 10 of 20 (50%), 7 of 20 (35%), and 1 of 20 (5%) teeth after canal instrumentation with the ProTaper, OneShape, and Reciproc files, respectively. The difference between the experimental groups was statistically significant (P < .001). CONCLUSIONS: Nickel-titanium instruments may cause cracks on the apical root surface or in the canal wall; the Self-Adjusting File and Reciproc files caused less cracks than the ProTaper and OneShape files.

Effects of self-adjusting file, Mtwo, and ProTaper on the root canal wall.

INTRODUCTION: The purpose of this ex vivo study was to observe the incidence of cracks in root dentin after root canal preparation with hand files, self-adjusting file (SAF), ProTaper, and Mtwo. METHODS: One hundred extracted mandibular premolars with single canals were randomly selected. Two angulated radiographs were taken for each tooth, and the width of the canal was measured at 9 mm from the apex. Five groups of 20 teeth each were comparable in canal width. The control group was left unprepared. Four experimental groups were instrumented with hand files, ProTaper, Mtwo, and SAF. Roots were then sectioned horizontally and observed under a microscope. The presence of dentinal cracks and their location were noted. The difference between the experimental groups was analyzed with a χ(2) test. RESULTS: No cracks were observed in the control group. In the experimental groups, ProTaper, Mtwo, and SAF caused cracks in 35%, 25%, and 10% of teeth, respectively. The hand-file group did not show any dentinal cracks (P < .0001). ProTaper and Mtwo caused more cracks than hand files (P < .05), but SAF did not (P > .05). CONCLUSIONS: Instrumentation of root canals with SAF, Mtwo, and ProTaper could cause damage to root canal dentin. SAF has a tendency to cause less dentinal cracks as compared with ProTaper or Mtwo.

Incidence of apical root cracks and apical dentinal detachments after canal preparation with hand and rotary files at different instrumentation lengths.

INTRODUCTION: The aim of this study was to compare the incidence of apical root cracks and dentinal detachments after canal preparation with hand and rotary files at different instrumentation lengths. METHODS: Two hundred forty mandibular incisors were mounted in resin blocks with simulated periodontal ligaments, and the apex was exposed. The root canals were instrumented with rotary and hand files, namely K3, ProTaper, and nickel-titanium Flex K files to the major apical foramen (AF), short AF, or beyond AF. Digital images of the apical surface of every tooth were taken during the apical enlargement at each file change. Development of dentinal defects was determined by comparing these images with the baseline image. Multinomial logistic regression test was performed to identify influencing factors. RESULTS: Apical crack developed in 1 of 80 teeth (1.3%) with hand files and 31 of 160 teeth (19.4%) with rotary files. Apical dentinal detachment developed in 2 of 80 teeth (2.5%) with hand files and 35 of 160 teeth (21.9%) with rotary files. Instrumentation with rotary files terminated 2 mm short of AF and did not cause any cracks. Significantly less cracks and detachments occurred when instrumentation with rotary files was terminated short of AF, as compared with that terminated at or beyond AF (P < .05). The AF deviated from the anatomic apex in 128 of 240 teeth (53%). Significantly more apical dentinal detachments appeared in teeth with a deviated AF (P = .033). CONCLUSIONS: Rotary instruments caused more dentinal defects than hand instruments; instrumentation short of AF reduced the risk of dentinal defects.

Removal of gutta-percha from root canals using the self-adjusting file.

INTRODUCTION: The aim of this study was to compare the percentage of the residual gutta-percha-occupied area (PRGPA) in root canals after retreatment using ProTaper retreatment files (Dentsply Maillefer, Ballaigues, Switzerland) with or without the additional use of Self-Adjusting Files (SAFs; ReDent-Nova, Ra'anana, Israel). METHODS: Root canals in 33 curved mesiobuccal roots of the first maxillary molars were cleaned and filled with gutta-percha and AH26 sealer (Dentsply De Trey, Johnson City, TN). Retreatment instrumentation was performed in 28 roots with ProTaper retreatment files and Hedström files. The Additional use of SAF was performed in 14 of the 28 roots. Five roots were not retreated. All roots were sectioned horizontally at 2, 4, and 6 mm from the apex. PRGPA was measured at each section. Scores 1 through 5 were used to represent the increasing extent of PRGPA; score 1 was 0%, and score 5 was >30%. The data were analyzed with nonparametric tests. RESULTS: Score 5 was recorded in all sections from roots that were not retreated. In retreated roots, the scores for the group using SAF were significantly lower than that without using SAF (P = .045); however, scores were higher at 2 mm than at other levels of the root regardless of whether the SAF had been used (P = .03). CONCLUSIONS: The complete removal of gutta-percha from the apical portion of curved canals remains a challenge. The additional use of SAF removed more gutta-percha than ProTaper alone.