Occlusal stress distribution and remaining crack propagation of a cracked tooth treated with different materials and designs: 3D finite element analysis.

OBJECTIVE: Here we used 3D finite element analysis (FEA) to analyze and directly compare stress distribution and crack propagation in identical cracked tooth models after treatment with various materials and designs. METHODS: A 3D model of a cracked tooth was generated. We then applied eight restoration models, comprising combinations of three kinds of restoration designs (inlay, onlay, and crown) and four types of restoration materials (direct composite resin, indirect composite resin, ceramic, and gold). A 1000-N occlusal load was applied on the three reference points of the ball-shaped part in the direction of the longitudinal axis, causing crack line separation in the buccolingual direction. Stress distribution was analyzed on the occlusal surface, bottom level of the restoration, and mesiodistal longitudinal section. The stress on the lower margin of the crack surface was measured at 15 points on each model. RESULTS: Ceramic inlay and onlay showed stress concentration at the restoration bottom, and low stress on the lower margin of the crack surface. Direct and indirect resin restorations exhibited low stress on the restoration bottom, and high stress on the proximal end of the lower margin of the crack surface. With a resin-unfilled gold crown, stress was concentrated on the crown bottom and the lower margin of the crack surface. Direct resin filling inside the gold crown yielded significantly decreased stress on both areas. SIGNIFICANCE: Our results suggest that inlay and onlay ceramic restorations, and gold crown with resin filling inside, are advantageous methods for preventing further crack propagation.

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.

HBV reactivation risk factors in patients with chronic HBV infection with low replicative state and resolved HBV infection undergoing hematopoietic stem cell transplantation in Korea.

PURPOSE: To elucidate the rate and risk factors of HBV reactivation in patients with chronic HBV infection with low replicative state and resolved HBV infection undergoing allogenic/autologous hematopoietic stem-cell transplantation (HSCT) in Korea. METHODS: The medical charts of 506 patients who underwent allogenic/autologous HSCT from January 2008 to December 2013 were analyzed retrospectively. We examined the reactivation rate and variables related to the risk of HBV reactivation, with a median follow-up period of 41.8 (1-245) months. Univariate analysis was used to identify any factors associated with HBV reactivation. Factors that were significant in the univariate analysis were entered into a stepwise multivariate analysis to find the most significant risk factors associated with HBV reactivation. RESULTS: The reactivation rate of HBV in patients who underwent HSCT was 4.2 % (21/506). In subgroup analysis, the HBV reactivation rate (14.3 %) was the highest among HBsAg(+) patients (5/35). The reactivation rate of HBV in patients with resolved HBV infection [HBsAg(-)/HBcAb(+) with or without anti-HBs antibody] was 5.9 % (10/171). In univariate analysis for risk factors of HBV reactivation in patients who underwent HSCT, initial detectable HBV DNA (p = 0.004), age (≥60 years) (p = 0.012), recipient hepatitis B surface antigen-positive (HbsAg)(+) before HSCT (p = 0.004), recipient hepatitis B surface antibody-negative (HBsAb)(-) before HSCT (p = 0.005), recipient hepatitis B core antibody-positive (HbcAb)(+) before HSCT (p = 0.013), and donor HBsAg(+) (p < 0.001) were associated with reactivation of HBV. In multivariate analysis, significant risk factors of HBV reactivation in patients who underwent HSCT were old age (≥60 years) (p = 0.032) and donor HBsAg(+) (p = 0.026). CONCLUSION: Old age (≥60 years) and donor HBsAg(+) were risk factors for HBV reactivation in HSCT patients. Preemptive antiviral treatment should be considered in these patients.

Utility of baseline impedance level measurement in patients with gastroesophageal reflux symptoms.

OBJECTIVE: Twenty-four-hour multichannel intraluminal impedance (MII) and pH monitoring is used for detecting reflux episodes in patients with gastroesophageal reflux (GER) disease. However, the clinical significance of baseline impedance levels (BILs) has not been well studied. We aimed to evaluate whether BILs are related to various reflux events or acid-related parameters and to determine whether BILs during specific intervals could be substituted for 24-h BILs. MATERIAL AND METHODS: One-hundred forty-two patients GER symptoms underwent 24-h pH/impedance monitoring. We measured pH [(5 cm above the low esophageal sphincter (LES)] and BILs from three sites (3, 5, and 15 cm above the LES). RESULTS: Eighty-one subjects (57.0%) were diagnosed with gastroesophageal reflux disease, and 53 (37.3%) had acid reflux and 28 (19.7%) had nonacid reflux. The 24-h BILs at distal sites were lower in the "reflux" group than in the "no reflux" group (p < 0.001) and lower in the "acid reflux" group than in the "nonacid reflux" group (p < 0.001). However, there was no significant difference in 24-h BILs at the proximal site among the "no reflux", "acid reflux", and "nonacid reflux" groups. The interclass correlation coefficient value of 24-h BILs with daytime 6-h BILs was 0.916 (95% CI 0.882-0.940) and that with nighttime 6-h BILs was 0.909 (95% CI 0.871-0.935). CONCLUSION: BILs are related to GER, especially acid reflux. Location and duration of assessment for BILs needs to be standardized. Six-hour BILs could be substitutes for 24-h BILs. During analysis of MII-pH, more attention should be paid to BILs in the lower esophagus.

Risk factors for small bowel bleeding in chronic nonsteroidal anti-inflammatory drug users.

OBJECTIVE: The incidence of nonsteroidal anti-inflammatory drugs (NSAIDs)-induced enteropathy is currently increasing. However, the predictors of small bowel bleeding (SBB) associated with NSAIDs are unknown. This study aimed to assess the risk factors of SBB in chronic NSAIDs users. METHODS: We retrospectively compared the medical records of 147 patients receiving NSAIDs in a tertiary-care setting (31 with SBB and 116 without previous bleeding events) and analyzed the predictors of SBB. RESULTS: In total, 31 patients underwent video capsule endoscopy to detect SBB, 74.2% of whom showed the evidence of SBB. Non-invasive treatment was performed in 90.3% of the patients. Multivariate logistic regression analysis revealed that the presence of coronary artery disease [adjusted odds ratio (aOR) 12.43, 95% confidence interval (CI) 1.19-130.34, P = 0.04], use of thienopyridine (aOR 16.93, 95% CI 3.78-75.72, P < 0.001) and prior use of rebamipide (aOR 0.31, 95% CI 0.12-0.82, P = 0.02) were independently associated with SBB in NSAIDs users. CONCLUSIONS: Coronary artery disease and co-use of thienopyridine were associated with SBB in NSAIDs users. The patients with coronary artery disease co-using thienopyridine need to be monitored for the occurrence of SBB when they were prescribed with NSAIDs.