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.

Radiographic study of the distribution of maxillary intraosseous vascular canal in Koreans.

BACKGROUND: This study aimed to investigate the distribution and prevalence of intraosseous loop (anastomosis between posterior superior alveolar artery and infraorbital artery) in Koreans detected on computed tomography (CT) images taken prior to sinus augmentation surgery. METHODS: From the 177 patients who underwent sinus augmentation with lateral approach at Ewha Womans University Department of Implant Dentistry, 284 CT scans were evaluated. The canal height (CH), ridge height (RH), and canal height from the sinus floor (CHS) were measured on para-axial views at the first premolar, first molar, and second molar. The horizontal positions of the bony canals in the lateral wall were also classified. One-way analysis of variance (ANOVA) and t test were used to estimate the statistical differences (p < 0.05). RESULTS: The intraosseous loops were detected in 92 CT scans (32 %). The mean vertical height of the bony canals from the alveolar crest (CH) was 23.45 ± 2.81, 15.92 ± 2.65, and 16.61 ± 2.92 mm at the second premolar, first molar, and second molar, respectively. In the horizontal positions of the bony canals, intraosseous type was the most predominant. The canal heights more than 15 mm and less than 17 mm were most prevalent (33.7 %) and those under 13 mm were 12.0 %. CONCLUSIONS: The radiographic findings in this study could be used to decide the lateral osteotomy line avoiding potential vascular complication. However, only one third of the canals could be detected in CT scans; a precaution should be taken for the possibility of severe bleeding during lateral osteotomy.

Evaluation of the Synergistic Effect Between Ethyl Formate and Phospine for Control of Aphis gossypii (Homoptera: Aphididae).

Cotton aphid, Aphis gossypii Glover, is known as a quarantine pest that is hard to control with short periods of fumigation with phosphine (PH(3)) or low concentrations of ethyl formate. Moreover, low-temperature fumigation with ethyl formate can lead to phototoxic damage of some perishable commodities. Therefore, a laboratory study was conducted to evaluate the synergistic effect of mixing ethyl formate and PH(3) for the treatment of adults and nymphs of A. gossypii. Combined toxicity was observed and compared with a single dose of eitherrethyl formate or PH(3). When insects were exposed to 0.5 g/m(3) of PH(3) combined with different levels of ethyl formate from 1.6 to 16.3 g/m(3) at 5 and 20C for 2 h, L(Ct)(50) and L(Ct)(99) values were greatly reduced in comparison with a single dose of either ethyl formate or PH(3). The synergistic ratio (SR) is described as L(Ct) of ethyl formate alone/L(Ct) of ethyl formate + PH(3). The SR values of L(Ct)(50) and L(Ct)(99) for adult A. gossypii at 5C were 4.55 and 2.33, respectively. However, at 20C the SR levels of L(Ct)(50) and L(Ct)(99) were 2.22 and 1.45, respectively, but still showed significant synergism (significant difference, P<0.5). This new technology could meet quarantine and preshipment requirements for shorter exposure times and less damage of perishable commodities, and could also be extended for controlling other quarantine pests and thereby be a useful alternative to methyl bromide for fruit and vegetable applications.

Fitness of gutta-percha cones in curved root canals prepared with reciprocating files correlated with tug-back sensation.

INTRODUCTION: The purpose of this study was to evaluate the gutta-percha-occupied area (GPOA) and the relationship between GPOA and tug-back sensations in canals instrumented with reciprocating files. METHODS: Twenty curved canals were instrumented using Reciproc R25 (VDW, Munich, Germany) (group R) and WaveOne Primary (Dentsply Maillefer, Ballaigues, Switzerland) (group W), respectively (n = 10 each). The presence or absence of a tug-back sensation was decided for both of #25/.08 and #30/.06 cones in every canal. The percentage of GPOA at 1-, 2-, and 3-mm levels from the working length was calculated using micro-computed tomographic imaging. The correlation between the sum of the GPOA and the presence of a tug-back sensation was also investigated. The data were analyzed statistically at P = .05. RESULTS: A tug-back sensation was present in 45% and 100% canals for #25/.08 and #30/.06 cones, respectively, with a significant difference (P < .05). At the 2- and 3-mm levels, #30/.06 cones produced significantly higher GPOA in groups R and W (P < .05). The sum of the GPOA score was significantly higher in the samples with a strong tug-back sensation (P < .05); however, there was no significant difference between the 2 cone types for this correlation (P > .05). CONCLUSIONS: Under the conditions of this study, the tug-back sensation can be a definitive determinant for indicating higher cone fitness in the curved canal regardless of the cone type.

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.

Cutting efficiency of apical preparation using ultrasonic tips with microprojections: confocal laser scanning microscopy study.

OBJECTIVES: The purpose of this study was to compare the cutting efficiency of a newly developed microprojection tip and a diamond-coated tip under two different engine powers. MATERIALS AND METHODS: The apical 3-mm of each root was resected, and root-end preparation was performed with upward and downward pressure using one of the ultrasonic tips, KIS-1D (Obtura Spartan) or JT-5B (B&L Biotech Ltd.). The ultrasonic engine was set to power-1 or -4. Forty teeth were randomly divided into four groups: K1 (KIS-1D / Power-1), J1 (JT-5B / Power-1), K4 (KIS-1D / Power-4), and J4 (JT-5B / Power-4). The total time required for root-end preparation was recorded. All teeth were resected and the apical parts were evaluated for the number and length of cracks using a confocal scanning micrscope. The size of the root-end cavity and the width of the remaining dentin were recorded. The data were statistically analyzed using two-way analysis of variance and a Mann-Whitney test. RESULTS: There was no significant difference in the time required between the instrument groups, but the power-4 groups showed reduced preparation time for both instrument groups (p < 0.05). The K4 and J4 groups with a power-4 showed a significantly higher crack formation and a longer crack irrespective of the instruments. There was no significant difference in the remaining dentin thickness or any of the parameters after preparation. CONCLUSIONS: Ultrasonic tips with microprojections would be an option to substitute for the conventional ultrasonic tips with a diamond coating with the same clinical efficiency.

Clinical efficiency and reusability of the reciprocating nickel-titanium instruments according to the root canal anatomy.

The application of the single-file technique using the reciprocating motion is gaining concern in root canal preparation. The purpose of this research is to compare the efficiency of the reciprocating motion-employing files (RECIPROC and WaveOne) by measuring the working time for complete canal shaping, and to evaluate their reusability under scanning examinations. One hundred curved root canals of the extracted molars were used. The working length was determined and the glide path was confirmed using a #15 K-file. Canals shaping was completed to the length either with RECIPROC R25 file (n = 50), or with WaveOne Primary file (n = 50). The time taken for the file to reach the working length was also measured. Each file was repeatedly used in a maximum of 10 canals for comparing the change of the efficiency (shaping time) according to the working length, canal curvature, and number of file re-use. The deformations or surface defects of the files after the in vitro use were observed using a scanning electron microscope (SEM). There was no difference under the SEM between the 2 file groups with no initiation of micro-cracks until they were re-used up to 5 canals. WaveOne Primary file showed significantly shorter working time than RECIPROC R25 (p < 0.05). There was a statistically significant correlation between the working time and three variables. As the working length and the curvature of the canal increased, the shaping time was increased in both file systems. Reusability of these reciprocating instruments might be maximum 5 canals with minimal surface deformations.

Increased Th17 differentiation in aged mice is significantly associated with high IL-1ß level and low IL-2 expression.

OBJECTIVE: Aging has been reported to be associated with changes in immune function. Although frequent infection and the development of malignancy suggest the decline of immune function with aging, changes toward proinflammatory conditions also develop at the same time. Th17 cells are well known CD4(+) T cell subpopulation closely linked to chronic inflammation and autoimmunity. In this study, changes in the Th17 population were investigated to elucidate a possible mechanism for this response with aging. METHODS: Splenocytes were isolated from 2-month-old (young) and 20-month-old (aged) mice. CD4(+)CD44(+) memory T cells and CD4(+)CD62L(+) naïve T cells were isolated and sorted using magnetic beads and flow cytometry. The frequency of IL-17-producing cells was measured using flow cytometry. The expression of IL-17 and Th17-related factors at the mRNA level was measured with RT-PCR. IL-17 and Il-1ß expression in spleen tissues was additionally assessed using confocal microscopy. RESULTS: The proportion of IL-17-producing CD4(+) T cells was higher in the splenocytes among the old mice than those of the young mice. When splenocytes were cultured in Th17 polarizing conditions, the proportion of IL-17 producing CD4(+) T cells was higher in aged mice as well. This was consistently observed when naïve and memory cells were isolated and differentiated into Th17 respectively. In addition, the expression of retinoic acid receptor-related orphan nuclear receptor gamma t (RORγt) and other Th17-related factors (AhR, CCR6, and CCL20) increased in the splenocytes of aged mice compared to the young mice. The expression of IL-1ß, showing to promote Th17 differentiation, was higher in the aged mice. Likewise, CD4(+) T cell expression of IL-1R was higher in the aged mice, suggesting that the CD4(+) T cells of the aged mice are readily prepared to differentiate into Th17 cells in response to IL-1ß. Confocal microscopy showed that cells positive for IL-1R or IL-1ß were more frequent in the spleens of the aged mice. When an anti-IL-2 antibody was applied, the proportion of IL-17-producing cells increased more prominently in the young mice. We observed that IL-2 production and IL-2R expression were reduced in the aged mice, respectively, explaining the blunted response to the anti-IL-2 antibody treatment and the consequent minimal change in the Th17 population. CONCLUSION: We demonstrated that the proportion of Th17 cells increased in the aged mice both in naïve and memory cell populations. Elevation of IL-1R and IL-1ß expression and the reduction in IL-2 and IL-2R expression in aged mice seemed to promote Th17 differentiation. Our results suggest that enhanced Th17 differentiation in aging may have a pathogenic role in the development of Th17-mediated autoimmune diseases.

Inhibition of kupffer cell activity improves transplantation of human adipose-derived stem cells and liver functions.

Numerous approaches to cell transplantation of the hepatic or the extrahepatic origin into liver tissue have been developed; however, the efficiency of cell transplantation remains low and liver functions are not well corrected. The liver is a highly immunoreactive organ that contains many resident macrophages known as Kupffer cells. Here, we show that the inhibition of Kupffer cell activity improves stem cell transplantation into liver tissue and corrects some of the liver functions under conditions of liver injury. We found that, when Kupffer cells were inhibited by glycine, numerous adipose-derived stem cells (ASCs) were successfully transplanted into livers, and these transplanted cells showed hepatoprotective effects, including decrease of liver injury factors, increase of liver regeneration, and albumin production. On the contrary, injected ASCs without glycine recruited numerous Kupffer cells, not lymphocytes, and showed low transplantation efficiency. Intriguingly, successfully transplanted ASCs in liver tissue modulated Kupffer cell activity to inhibit tumor necrosis factor-α secretion. Thus, our data show that Kupffer cell inactivation is an important step in order to improve ASC transplantation efficiency and therapeutic potential in liver injuries. In addition, the hepatoprotective function of glycine has synergic effects on liver protection and the engraftment of ASCs.

Effect of laser-activated irrigation of 1320-nanometer Nd:YAG laser on sealer penetration in curved root canals.

INTRODUCTION: The purpose of this study was to investigate the efficacy of laser-activated irrigation (LAI) of 1320-nm neodymium-doped:yttrium-aluminum-garnet (Nd:YAG) laser on sealer penetration into dentinal tubules in the presence of 5.25% sodium hypochlorite (NaOCl) or 17% ethylenediaminetetraacetic acid (EDTA). METHODS: The curved root canals (>20°) from 63 extracted human molars (negative control, n = 3) were prepared to size #30.06 with NaOCl irrigation. Teeth were divided into 4 groups (n = 15) as follows: group N, NaOCl irrigation without LAI; group E, EDTA irrigation without LAI; group NL, LAI with NaOCl; group EL, LAI with EDTA. In all groups, the laser fiber was inserted and withdrawn 4 times for 5 seconds each. Teeth were obturated with gutta-percha and fluorescent-labeled sealer. Transverse sections at 2 and 5 mm from root apex were examined with confocal laser scanning microscopy, and the percentage of sealer penetration into dentinal tubules was measured. RESULTS: Groups E, NL, and EL showed higher percentage of sealer penetration than group N (P < .05). With NaOCl as irrigant, LAI (group NL) resulted in significantly higher amount of sealer penetration than nonactivated group (group N) in both levels (P < .05). However, with EDTA, no significant differences in sealer penetration were observed between the laser-activated group (group EL) and its nonactivated counterpart (group E) in both levels (P > .05). CONCLUSIONS: The 1320-nm Nd:YAG laser activation with either NaOCl or EDTA was much better than NaOCl irrigation alone and as effective as EDTA final flush for sealer penetration into dentinal tubules. Additional use of laser with EDTA did not improve the quality of obturation in the curved canals.

Homing of adipose-derived stem cells to radiofrequency catheter ablated canine atrium and differentiation into cardiomyocyte-like cells.

BACKGROUND AND OBJECTIVES: The purpose was to determine whether human adipose-derived stem cells (h-ASCs) can home to the radiofrequency ablated myocardial lesions when injected intravenously and differentiate into cardiomyocyte. METHODS: Human adipose tissues were obtained from patients and h-ASCs were isolated and cultured. The phenotype of isolated h-ASCs was identified by flow cytometry. Radiofrequency catheter ablation (RFCA) was performed with ten ablation pulses (40 W, 60 s each) to induce heat-mediated lesions at the free walls of the right atria of 14 dogs. Twenty-four hours after ablation, h-ASCs (1 × 10(7) cells) labeled with superparamagnetic iron oxide particles (SPIOs) were infused intravenously in 10 dogs as cell-therapy group and only saline without cells was infused in 4 dogs as control. The hearts were explanted 4 weeks later. RESULTS: h-ASCs were identified by flow cytometry as mesenchymal stem cell as positive for CD 13, CD29, CD44, CD90, CD166 and HLA-ABC and immunophenotyping revealed no immunologic responses. SPIO-labeled cells were identified in areas surrounding the RFCA-induced lesions by Prussian blue staining. Immunohistochemistry staining showed positive for anti-α-actinin, anti-cardiac troponin-I, anti-connexin 43 and anti-VEGFR-2. No lymphocyte infiltration, immunorejection or neoplasm-like cells were found in the h-ASC-positive areas. However, multiple iron-labeled h-ASCs were detected in lungs and spleens of cell-therapy group. CONCLUSION: h-ASCs can home into injured atrial tissue and express a cardiomyocyte-like phenotype, suggesting that intravenous delivery of stem cells might be feasible. Functional studies and quantification of delivered stem cells are needed for better evaluation and understanding of differentiation into cardiomyocytes.

Systemic transplantation of human adipose-derived stem cells stimulates bone repair by promoting osteoblast and osteoclast function.

Systemic transplantation of adipose-derived stem cells (ASCs) is emerging as a novel therapeutic option for functional recovery of diverse damaged tissues. This study investigated the effects of systemic transplantation of human ASCs (hASCs) on bone repair. We found that hASCs secrete various bone cell-activating factors, including hepatocyte growth factor and extracellular matrix proteins. Systemic transplantation of hASCs into ovariectomized mice induced an increased number of both osteoblasts and osteoclasts in bone tissue and thereby prevented bone loss. We also observed that conditioned medium from hASCs is capable of stimulating proliferation and differentiation of osteoblasts via Smad/extracellular signal-regulated kinase (ERK)/JNK (c-jun NH(2) -terminal kinase) activation as well as survival and differentiation of osteoclasts via ERK/JNK/p38 activation in vitro. Overall, our findings suggest that paracrine factors secreted from hASCs improve bone repair and that hASCs can be a valuable tool for use in osteoporosis therapy.

Effect of final irrigation regimen on sealer penetration in curved root canals.

INTRODUCTION: The purpose of this study was to evaluate the effect of different final irrigation regimens on the sealer penetration into dentinal tubules of curved root canals. METHODS: The mesiobuccal canals from 45 extracted maxillary and mandibular molars were instrumented with sodium hypochlorite (NaOCl) irrigation. The samples were divided into 3 groups according to the final irrigation used: group N (control), 3.5% NaOCl; group E, 17% ethylenediaminetetraacetic acid (EDTA); and group EN, 17% EDTA followed by 3.5% NaOCl. All teeth were obturated with gutta-percha and AH Plus sealer labeled with fluorescent dye. Transverse sections at 2 mm (apical) and 5 mm (coronal) from root apex were examined by using confocal laser scanning microscopy. Then, total percentage and maximum depth of sealer penetration were measured. RESULTS: The apical sections in each group showed significantly lower percentage and maximum depth of sealer penetration than the coronal sections (P < .05). In apical levels, group E and EN resulted in a higher percentage of sealer penetration than the control group (P < .05), but there was no significant difference of maximum depth between group E and the control group (P > .05). CONCLUSIONS: In curved canal, final rinse with NaOCl after the use of EDTA had no additional effect on sealer penetration. Complete debridement with a 1-minute application of EDTA remains a challenge in the apical area of curved canals.

Interleukin-18 induces the production of vascular endothelial growth factor (VEGF) in rheumatoid arthritis synovial fibroblasts via AP-1-dependent pathways.

Interleukin-18 (IL-18) is a novel pro-inflammatory cytokine which has been implicated to play a pathogenic role in rheumatoid arthritis (RA). Vascular endothelial growth factor (VEGF) plays an important role in angiogenesis in rheumatoid synoviocytes. In present study, we examined the effect of IL-18 on VEGF production in fibroblast-like synoviocytes (FLS) isolated from the patients with RA. FLS were prepared from the synovial tissues of patients with RA and osteoarthritis (OA) and cultured in the presence of IL-18. The production of VEGF from FLS was measured in culture supernatants by enzyme-linked immunosorbent assay (ELISA). The VEGF messenger RNA (mRNA) expression and AP-1 binding activity of VEGF transcript were determined by reverse transcription-polymerase chain reaction (RT-PCR) and electrophoretic mobility shift assay (EMSA). IL-18 and VEGF levels of sera and synovial fluids (SF) of RA patients (n=30) were significantly higher than those of OA patients (n=20). IL-18 dose-dependently increased the production of VEGF. The effect of IL-18 on VEGF production appeared to be as potent as IL-1beta, whereas tumor necrosis factor (TNF)-alpha and interferon (IFN)-gamma showed little effects on VEGF production. AP-1-specific inhibitor Curcumin dose-dependently abrogated the effect of IL-18 on VEGF production. The VEGF enhancement of IL-18 was associated with increased AP-1 binding activity to the VEGF promoter site. These findings suggest IL-18 as an angiogenic factor in RA and down-regulation of IL-18 activity or AP-1 signal pathway can be potential therapeutic targets for RA.