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Benzophenone-3 (BP-3) is one of the organic ultraviolet (UV) filters widely used in personal care products, resulting in its ubiquitous occurrence in aquatic systems. This study discovered the potential risks of benzophenone-3 and its metabolites (BP-1 and BP-8) in aquatic environments. This study investigated the toxicity of three single BPs and their mixtures' effects on the survival of Daphnia magna. All three BP types were found to have toxic effects on D. magna, with median effective concentration (EC50) values of 22.55 mg/L for BP-1, 1.89 mg/L for BP-3, and 2.36 mg/L for BP-8, after 48 h of exposure. When the three BPs were binary and ternary mixtures, the EC50 values fell within 2.74-32.26 mg/L. Binary and tertiary mixtures of the three BPs indicated no strong synergistic or antagonistic effects. The mixture toxicity predictions using the classical mixture concept of concentration addition and measured toxicity data showed good predictability. The ecological risks of BPs were assessed using the maximum measured environmental concentrations of BPs collected from a river in Taiwan, divided by their respective predicted no-effect concentration (PNEC) values derived from the assessment factor (AF) method. The result showed a low ecological risk for the sum of three BPs. However, BP-3 had the highest potential risk, while BP-1 was the lowest among the three BPs. Therefore, BP-3 should pay attention to long-term environmental monitoring and management. This study provides valuable information for establishing scientifically-based water quality criteria for BPs and evaluating and managing the potential risk of BPs in the aquatic environment., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier Ltd. All rights reserved.)

Background: Colorectal cancer (CRC) is a primary cause of cancer-related mortality, and, after treatment, cancer survivors often worry that disease recurrence may worsen their health. Nevertheless, limited research on fear of cancer recurrence (FCR) and treatment-related symptoms has been conducted on survivors of CRC., Purpose: This study was designed to explore (1) symptom distress severity and post-treatment FCR in CRC survivors and (2) the predictors of FCR., Methods: A cross-sectional correlational research design and convenience sampling approach were used to recruit patients at the colorectal surgery outpatient department of a medical center in central Taiwan. Basic demographic data, the Symptom Distress Scale - Chinese Modified Form, and Fear of Progression Questionnaire - Short Form were used as monitoring tools. Pearson's product-moment correlation analysis, independent t-tests, one-way ANOVA, and stepwise linear regression analysis were used for statistical analysis., Results: One hundred fourteen survivors of CRC with an average age of 63.44 were enrolled as participants. The top five symptoms of distress were numbness, bowel patterns, fatigue, insomnia, and dry mouth, and the average FCR score was 18.09. Gender, educational level, monthly disposable income, and symptom distress were identified as significant predictors of FCR, with an overall explanatory power of 41.4%., Conclusions: Level of post-treatment FCR in survivors of CRC is influenced by symptom distress severity. Early intervention by healthcare providers to control or alleviate physical symptoms can help prevent the emergence of negative emotions and improve quality of life in this patient group.

Coumarin-3-carboxylic acid (3-CCA), previously screened from natural coumarins, was found to possess strong antibacterial activity against Acidovorax citrulli ( Ac ). In order to further evaluate the activity of this compound against plant bacterial pathogens and explore its potential value as a bactericidal lead compound, the activity of 3-CCA against 14 plant pathogenic bacteria in vitro and in vivo was tested. Results showed that 3-CCA exhibited strong in vitro activities against Ac, Ralstonia solanacearum, Xanthomonas axonopodis pv. manihotis, X. oryzae pv. oryzae , and Dickeya zeae with EC 50 values ranging from 26.64 μg/mL to 40.73 μg/mL. Pot experiment results showed that 3-CCA had powerful protective and curative effects against Ac . In addition, the protective efficiency of 3-CCA was almost equivalent to that of thiodiazole copper at the same concentration. The results of SEM and TEM observation and conductivity tests showed that 3-CCA disrupted the integrity of the cell membrane and inhibited polar flagella growth. Furthermore, 3-CCA resulted in reductions in motility and extracellular exopolysaccharide (EPS) production of Ac while inhibiting the biofilm formation of Ac . These findings indicate that 3-CCA could be a promising natural lead compound against plant bacterial pathogens to explore novel antibacterial agents., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2023 Zhu, Fu, Ye, Ding, Gu, Zhang, Guo and Feng.)

Objectives: The present review discussed the biomechanical properties of cracks and fractures in crown and root dentine and attempted to explain why cracked teeth and vertical root fractures are so frequent despite the existence of multiple crack toughening mechanisms in dentine. The implications of this knowledge were used to justify how these defects are managed clinically., Data, Sources and Study Selection: Literature search was conducted on PubMed, Web of Science, and Scopus for a narrative review on fracture mechanics of crown and root dentine as well as the clinical management of cracked teeth and teeth with vertical root fracture., Conclusions: Although dentine is tougher and less brittle than enamel, it's facture toughness is considerably lower than most ductile metals. Because the initiation toughness of dentine is very low, cracks initiate from incipient damage under low stress While crack toughening mechanisms exist that enable dentine to resist crack extension, these mechanisms are often inadequate for protecting dentine from crack propagation that ultimately leads to catastrophic failure. Additional factors such as ageing also reduces the resistance of dentine to crack growth. Because dentine cracks are eventually filled with bacteria biofilms upon exposure to oral fluids, they enable rapid bacteria ingress into the dental pulp via open dentinal tubules. To date, treatment options for cracked teeth are limited. While most teeth with vertical root fracture are recommended for extraction, new strategies have been reported that appeared to achieve short-term success in preserving these teeth., Clinical Significance: Current strategies for the management for dentine cracks and fractures are limited and their long-term effectiveness remain uncertain. Understanding the characteristics, toughening mechanism and weakening factors of tooth cracks is helpful in designing better treatment., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Published by Elsevier Ltd.)

Background/purpose: There is no consensus to date on how many repetitive pecking motions at working length (WL) should be regarded as optimal during instrumentation. Therefore, this study aimed to evaluate the effect of pecking frequency at WL on the volume of apically extruded debris using three single-file systems in curved, oval-shaped canals., Materials and Methods: Forty-five single-rooted mandibular premolars with curved, oval-shaped canals were prescanned by micro-computed tomography, anatomically paired-matched, and randomly divided among three groups (n = 15 each): Reciproc Blue (RB), WaveOne Gold (WOG) and XP-endo Shaper (XPS). Samples were embedded in agarose gel to collect extruded debris. After preparation to the WL, each sample was rescanned after one, two, four, 10, and 20 pecking motions at WL, respectively. The debris volume was innovatively calculated by a modification of an existing method using micro-computed tomography. The apical preparation size was also measured. Data were compared using a two-way repeated-measures analysis of variance., Results: All single-file systems extruded debris apically, irrespective of the pecking frequency at WL. The extruded debris volume correlated positively with the minor foramen size ( P  < 0.05); both increased with pecking frequency for each single-file system ( P  < 0.05). The minor foramen size corresponded to the instrument tip size when reaching the WL once., Conclusion: To produce less debris extrusion and obtain a predictable foramen size corresponding to the instrument tip size, a single pecking motion may be preferred when using single-file systems. Caution should be exercised when applying the current results to clinical situations., Competing Interests: The authors have no conflicts of interest relevant to this article., (© 2021 Association for Dental Sciences of the Republic of China. Publishing services by Elsevier B.V.)

Numerous transcription factors (TFs) in ascomycete fungi play crucial roles in cellular processes; however, how most of them function is poorly understood. Here, we identified and characterized a novel TF, CxrC (POX01387), acting downstream of the key TF CxrA, which is essential for plant-biomass-degrading-enzyme (PBDE) production in Penicillium oxalicum. Deletion of cxrC in P. oxalicum significantly affected the production of PBDEs, as well as mycelial growth and conidiospore production. CxrA directly repressed the expression of cxrC after about 12 hr following switch to Avicel culture. CxrC bound the promoters of major PBDE genes and genes involved in conidiospore development. CxrC was found to bind the TSSGTYR core sequence (S: C and G; Y: T and C; R: G and A) of the important cellulase genes cbh1 and eg1. Both N- and C-terminal peptides of CxrC and the CxrC phosphorylation were found to mediate its homodimerization. The conserved motif LPSVRSLLTP (65-74) in CxrC was found to be required for regulating cellulase production. This study reveals novel mechanisms of TF-mediated regulation of the expression of PBDE genes and genes involved in cellular processes in an ascomycete fungus., (© 2021 John Wiley & Sons Ltd.)

Phospholipases play vital roles in immune and inflammatory responses in mammals and plants; however, knowledge of phospholipase functions in fungi is limited. In this study, we investigated the effects of deleting predicted phospholipase genes on cellulase and xylanase production, and morphological phenotype, in Penicillium oxalicum. Individual deletion of nine of the ten predicted phospholipase genes resulted in alteration of cellulase and xylanase production, and the morphological phenotypes, to various degrees. The mutant ∆POX07277 lost 22.5 to 82.8% of cellulase (i.e., filter paper cellulase, carboxymethylcellulase, and p-nitrophenyl-β-cellobiosidase) and xylanase production, whereas p-nitrophenyl-β-glucopyranosidase production increased by 5.8-127.8 fold. POX07277 (P. oxalicum gene No. 07277) was predicted to encode phospholipase A2 and was found to negatively affect the sporulation of P. oxalicum. Comparative transcriptomic and quantitative reverse transcription-PCR analysis indicated that POX07277 dynamically affected the expression of cellulase and xylanase genes and the regulatory genes for fungal sporulation, under micro-crystalline cellulose induction. POX07277 was required for the expression of the known regulatory gene PoxCxrB (cellulolytic and xylanolytic regulator B in P. oxalicum), which is involved in cellulase and xylanase gene expression in P. oxalicum. Conversely, POX07277 expression was regulated by PoxCxrB. These findings will aid the understanding of phospholipase functions and provide novel insights into the mechanism of fungal cellulase and xylanase gene expression. KEY POINTS : • The roles of phospholipases were investigated in Penicillium oxalicum. • POX07277 (PLA 2 ) is required for the expression of cellulase and xylanase genes. • PoxCxrB dynamically regulated POX07277 expression.

Background: Application of raw starch-degrading enzymes (RSDEs) in starch processing for biofuel production can effectively reduce energy consumption and processing costs. RSDEs are generally produced by filamentous fungi, such as Penicillium oxalicum, but with very low yields, which seriously hampers industrialization of raw starch processing. Breeding assisted by random mutagenesis is an efficient way to improve fungal enzyme production., Results: A total of 3532 P. oxalicum colonies were generated after multiple rounds of mutagenesis, by atmospheric and room-temperature plasma (ARTP) and/or ethyl methanesulfonate (EMS). Of these, one mutant A2-13 had the highest RSDE activity of 162.7 U/mL, using raw cassava flour as substrate, a yield increase of 61.1%, compared with that of the starting strain, OXPoxGA15A. RSDE activity of A2-13 further increased to 191.0 U/mL, through optimization of culture conditions. Increased expression of major amylase genes, including the raw starch-degrading glucoamylase gene, PoxGA15A, and its regulatory gene, PoxAmyR, as well as several single-nucleotide polymorphisms in the A2-13 genome, were detected by real-time reverse transcription quantitative PCR and genomic re-sequencing, respectively. In addition, crude RSDEs produced by A2-13, combined with commercial α-amylase, could efficiently digest raw corn flour and cassava flour at 40 °C., Conclusions: Overall, ARTP/EMS-combined mutagenesis effectively improved fungal RSDE yield. An RSDE-hyperproducing mutant, A2-13, was obtained, and its RSDEs could efficiently hydrolyze raw starch, in combination with commercial α-amylase at low temperature, which provides a useful RSDE resource for future starch processing.

Dental fluorosis is the most common and prominent symptom in the early stage of chronic fluorosis, which is caused by excessive fluorine intake during tooth development. In severe cases, it may be accompanied by skeletal fluorosis. There are also systemic damages to the nervous system, cardiovascular system, endocrine system and so on. The pathogenesis of dental fluorosis is not totally clear, which may be a complex pathological process involving both genetic and environmental factors. The prevalence of dental fluorosis has an upward trend arround the world, thus certain public prevention and treatment strategies need to be taken. This article focuses on the prevalence, etiology, diagnosis and scoring system, as well as the public prevention and treatment strategies, of dental fluorosis, so that to provide reference for the research and prevention of the disease.

Background: Locally advanced breast cancer (LABC) is one of the subgroups of invasive breast cancer. The treatment of LABC is neoadjuvant chemotherapy (NAC) before surgery, which is different from the others. The study aimed to analyze and compare the characteristics of conventional ultrasound, contrast-enhanced ultrasonography (CEUS) and strain elastography (SE) in LABC patients who have different treatment outcomes, and to provide help for LABC in the imaging diagnosis and clinic treatment., Methods: From May 2018 to April 2019, 36 patients (40 lesions) of LABC were enrolled, which diagnosed by puncture biopsy. According to the clinical evaluation, these patients were recommended to undergo pre-operative NAC followed by surgery. All patients underwent conventional ultrasound, CEUS and SE before puncture. According to postoperative pathological grading and follow-up, the patients were divided into effective and ineffective groups. We summarized and compared the features of conventional ultrasound, CEUS and SE of patients in two groups. The correlation between the imaging characteristics and the postoperative pathological grading was also analyzed., Results: Conventional ultrasonic features of LABC: the most lesions of LABC were mass type (32/40, 80.0%), and all lesions were irregular. Most of lesions showed unclear boundaries (39/40, 97.5%), heterogeneous echoes (38/40, 95.0%), and internal calcifications (24/40, 60.0%). Most of lesions had hyperechoic halos (31/40, 77.5%), aspect ratio less than or equal to 1 (34/40, 85.0%), and blood flow grading was III (36/40, 90.0%). CEUS features of LABC: compared with the surrounding normal tissues, all the lesions (40/40,100.0%) were highly enhanced. Most of lesions (35/40, 87.5%) were uneven enhanced. The main enhancement mode was "fast in and slow out" (39/40, 97.5%). There were totally 25 lesions which had "solar sign" (25/40, 62.5%). SE features of LABC: the average visual elastography score of the lesions was 4.28±0.67, the maximum strain rate (E1) of the lesions averaged 4.88±0.54, and the overall strain rate of the lesion averaged 4.14±0.72. There was no significant difference between effective and ineffective groups in the characteristics of conventional ultrasound, CEUS and SE. There was a correlation between the appearance of "solar sign" in CEUS and postoperative pathological grading, and the contingency coefficient was 0.564 (P<0.05). The pathological grading of patients without solar sign was higher. The other characteristics of conventional ultrasound, CEUS and SE in LABC patients had no correlation with postoperative pathological grading., Conclusions: In LABC, the conventional ultrasound usually shows irregular shape and unclear boundaries. The aspect ratio is less than or equal to 1. CEUS showed uneven enhancement of "fast in and slow out", and "solar sign" was often seen. Elastography showed that the texture of the lesion was significantly stiffer than the surrounding normal tissue. Ultrasound imaging before NAC had no relationship with pathological complete response or not. However, "solar sign" in CEUS was an important feature and had correlation with postoperative pathological grading., Competing Interests: Conflicts of Interest: The authors have no conflicts of interest to declare., (2019 Journal of Thoracic Disease. All rights reserved.)

Transcriptional regulation of cellulolytic and xylolytic genes in ascomycete fungi is controlled by specific carbon sources in different external environments. Here, comparative transcriptomic analyses of Penicillium oxalicum grown on wheat bran (WB), WB plus rice straw (WR), or WB plus Avicel (WA) as the sole carbon source under solid-state fermentation (SSF) revealed that most of the differentially expressed genes (DEGs) were involved in metabolism, specifically, carbohydrate metabolism. Of the DEGs, the basic core carbohydrate-active enzyme-encoding genes which responded to the plant biomass resources were identified in P. oxalicum , and their transcriptional levels changed to various extents depending on the different carbon sources. Moreover, this study found that three deletion mutants of genes encoding putative transcription factors showed significant alterations in filter paper cellulase production compared with that of a parental P. oxalicum strain with a deletion of Ku70 (Δ PoxKu70 strain) when grown on WR under SSF. Importantly, the Δ PoxAtf1 mutant (with a deletion of P. oxalicum Atf1 , also called POX03016 ) displayed 46.1 to 183.2% more cellulase and xylanase production than a Δ PoxKu70 mutant after 2 days of growth on WR. RNA sequencing and quantitative reverse transcription-PCR revealed that PoxAtf1 dynamically regulated the expression of major cellulase and xylanase genes under SSF. PoxAtf1 bound to the promoter regions of the key cellulase and xylanase genes in vitro This study provides novel insights into the regulatory mechanism of fungal cellulase and xylanase gene expression under SSF. IMPORTANCE The transition to a more environmentally friendly economy encourages studies involving the high-value-added utilization of lignocellulosic biomass. Solid-state fermentation (SSF), that simulates the natural habitat of soil microorganisms, is used for a variety of applications such as biomass biorefinery. Prior to the current study, our understanding of genome-wide gene expression and of the regulation of gene expression of lignocellulose-degrading enzymes in ascomycete fungi during SSF was limited. Here, we employed RNA sequencing and genetic analyses to investigate transcriptomes of Penicillium oxalicum strain EU2101 cultured on medium containing different carbon sources and to identify and characterize transcription factors for regulating the expression of cellulase and xylanase genes during SSF. The results generated will provide novel insights into genetic engineering of filamentous fungi to further increase enzyme production., (Copyright © 2019 American Society for Microbiology.)

Cisplatin is a highly effective antitumor drug, which can kill cancer cells by crossing-linking DNA and inhibiting transcription, but this process is limited by the combination of cisplatin and many endogenous nucleophiles, such as glutathione (GSH). Thus, when cisplatin enter cells, it is potentially vulnerable to cytoplasmic inactivation by GSH. To settle this bottleneck, we designed and synthesized a probe compound (Probe 1) and fabricated pH-responsed cisplatin, Probe 1-loaded lipid-polymer hybrid NanoParticles (CPNPs) using a single-step sonication method. Probe 1 can specifically bind to GSH, thus avoiding the combination of GSH and cisplatin, and enhancing the pharmacological activity of cisplatin. In vitro studies have suggested CPNPs, compared with cisplatin, loaded lipid-polymer hybrid NanoParticles CNPs (Not contain Probe 1), could efficiently kill MCF-7 human breast cancer cells and A549 human nonsmall lung cancer cell. Hence, the CPNPs provided a new idea for treating cancer., (Copyright © 2018 Elsevier B.V. All rights reserved.)

Instability of resin-dentin bonds is the Achilles' heel of adhesive dentistry. To address this problem, a chelate-and-rinse extrafibrillar dentin demineralization strategy has been developed that keeps intrafibrillar minerals within collagen fibrils intact to prevent activation of endogenous proteases that are responsible for collagen degradation within hybrid layers. The objective of the present study was to evaluate the potential of using chitosan >40 kDa as an antimicrobial extrafibrillar dentin-chelating agent to enhance bond durability. Transmission electron microscopy provided evidence for retention of intrafibrillar minerals and smear plugs in dentin conditioned with 1 wt% chitosan. Analyzed by Kruskal-Wallis analysis of variance, Dunn's statistic, and separate Mann-Whitney tests, tensile bond strengths to wet- and dry-bonded dentin indicated that chelating dentin with chitosan for 60 s prior to bonding did not result in a significant decline in resin-dentin bond strength when compared with that of phosphoric acid etching ( P > 0.05). Gelatinolytic activity within the hybrid layers was examined via in situ zymography after 24-h storage or after thermomechanical cycling and analyzed with 3-factor analysis of variance. After 24 h, enzymatic activity was detected only within completely demineralized phosphoric acid-etched dentin, with values derived from dry bonding significantly higher than those derived from wet bonding ( P < 0.05). Negligible fluorescence was detected within hybrid layers when dentin was conditioned with chitosan, even after thermomechanical cycling, as compared with the controls. Reduction in water permeability in chitosan-conditioned dentin, attributed to smear plug retention, also fostered long-term bond stability. Antibacterial testing performed with live/dead staining indicated that the acetic acid-solubilized chitosan possessed antibacterial activities against 3 single-species biofilms: Streptococcus mutans, Actinomyces naeslundii, and Enterococcus faecalis. Taken together, the new chitosan-based extrafibrillar demineralization strategy retains intrafibrillar minerals, reduces endogenous protease-initiated collagen degradation, prevents water permeation within hybrid layers, and kills bacteria on dentin surfaces, which are crucial factors for enhancing resin-dentin bond durability.

Objectives: The water-associated attributes of resin-dentin interfaces created by contemporary adhesives are important determinants of bond integrity and stability. In the present work, these attributes were estimated from the perspectives of causality, to examine the behavior of the first and most-recently launched versions of universal adhesives when applied in either the etch-and-rinse mode or the self-etch mode., Methods: The immediate cause of interfacial permeability and the time-dependent cause of water sorption were investigated in conjunction with the intermediate effect of interface degradation and the more long-term effect of loss of mechanical strength, before and after thermomechanical cycling. The results were compared with control etch-and-rinse and self-etch adhesives., Results: Although the introduction of this new class of universal adhesives has brought forth significant changes to the dental adhesion arena, including more application options, reduced bonding armamentarium and increased user friendliness, the water-associated attributes that are critical for making resin-dentin bonds more durable to environmental challenges and less susceptible to degradation have remained unchanged at large, when compared with benchmarks established by former classes of adhesives., Conclusion: It appears that the current trend of adhesive development has brought forth significant changes but lacks the vigor that demarcates progress and technological sublimity., Clinical Significance: The advent of the user friendly universal adhesives has brought forth significant changes to the dental adhesion arena. However, the elements that are critical for making resin-dentin bonds more durable to environmental challenges and less susceptible to degradation have remained unchanged at large., (Copyright © 2018 Elsevier Ltd. All rights reserved.)

Objectives: The objective of the present study was to elucidate the mechanism of bioactive molecule extraction from mineralized dentin by calcium hydroxide (Ca(OH) 2 ) and tricalcium silicate cements (TSC)., Methods and Results: Transmission electron microscopy was used to provide evidence for collagen degradation in dentin surfaces covered with Ca(OH) 2 or a set, hydrated TSC for 1-3 months. A one micron thick collagen degradation zone was observed on the dentin surface. Fourier transform-infrared spectroscopy was used to identify increases in apatite/collagen ratio in dentin exposed to Ca(OH) 2 . Using three-point bending, dentin exposed to Ca(OH) 2 exhibited significant reduction in flexural strength. Using size exclusion chromatography, it was found that the small size of the hydroxyl ions derived from Ca(OH) 2 enabled those ions to infiltrate the intrafibrillar compartment of mineralized collagen and degrade the collagen fibrils without affecting the apatite minerals. Using ELISA, TGF-β1 was found to be extracted from dentin covered with Ca(OH) 2 for 3 months. Unlike acids that dissolve the mineral component of dentin to release bioactive molecules, alkaline materials such as Ca(OH) 2 or TSC released growth factors such as TGF-β1 via collagen degradation., Significance: The bioactive molecule extraction capacities of Ca(OH) 2 and TSC render these dental materials excellent for pulp capping and endodontic regeneration. These highly desirable properties, however, appear to be intertwined with the untoward effect of degradation of the collagen matrix within mineralized dentin, resulting in reduced flexural strength., (Copyright © 2017 The Academy of Dental Materials. Published by Elsevier Ltd. All rights reserved.)

Objectives: To evaluate the effect of intrinsic water permeation on the microtensile bond strengths of different adhesive systems to dentine and the quality of resin-dentine interfaces., Methods: Ninety-six non-carious human third molars were divided into 4 groups: Clearfil S 3 Bond Plus (CSBP; Kuraray); Clearfil S 3 Bond (C3S; Kuraray); iBond Self-Etch (IB; Heraeus-Kulzer) and Prime&Bond NT (PB, control etch-and-rinse adhesive, Dentply-Sirona). For each adhesive, specimens from one subgroup (N=10) were bonded using zero pulpal pressure, while specimens from the other subgroup (N=10) were bonded using 15cm water pressure (PP). Each bonded tooth was sectioned into 1×1mm sticks and stressed to failure. Data were analysed using two-way ANOVA and Holm-Sidak pairwise comparisons to examine the effects of "adhesive", "pulpal pressure" and their interaction on bond strength (α=0.05). Representative fractured sticks were examined by SEM. The remaining tooth slabs in each subgroup were used for TEM and CLSM., Results: Microtensile bond strengths (mean±SD; in MPa) were: 33.4±6.9 (CSBP), 33.2±4.7 (CSBP-PP), 35.0±8.6 (C3S), 25.5±7.3 (C3S-PP), 18.4±4.0 (IB), 16.5±6.9 (IB-PP), 28.2±5.5 (PB), 20.5±7.2 (PB-PP). "Adhesive-type" (P<0.001), "pulpal-pressure" (P<0.001) and their interactions (P<0.001) significantly affected bond strength results. No difference between no-PP and PP subgroups was found for CSBP and IB (P>0.05). Water droplets were identified along the resin-dentine interface for IB, IB-PP and C3S-PP., Conclusion: IB exhibits water sensitivity when bonding is performed with/without pulpal pressure. C3S exhibits water sensitivity when bonding is performed with pulpal pressure. CSBP does not exhibit water sensitivity when bonding is performed with/without pulpal pressure., Clinical Significance: Intrinsic water permeation during bonding procedures significantly affects bond strength results and the resin-dentine interface of contemporary single-bottle self-etch dentine adhesive systems., (Copyright © 2017. Published by Elsevier Ltd.)

Background: Although primary thyroid lymphoma (PTL) and anaplastic thyroid carcinoma (ATC) both account for a rare portion of the morbidity of all thyroid malignancies, the therapeutic methods and prognosis for these two diseases are different. The purpose of this study was to investigate the sonographic characteristics of PTL and ATC and to compare the sonographic findings of PTL and ATC., Methods: The study included 42 patients with histopathologically proven PTL (n=27) and ATC (n=15). The Clinical characteristics and sonographic findings were retrospectively reviewed and compared between the two groups., Results: The mean age of patients with ATC was not significantly different from that in patients with PTL (P=0.601). The female-to-male ratio of patients with ATC was significantly lower than that of patients with PTL (P=0.029). Both PTL and ATC commonly present as a relatively large, solid mass on sonography with compressive symptoms, in which hoarseness was seen more frequently in ATC group (66.7%) than in PTL group (14.8%) (P=0.001). There is no significant difference in thyroid size, nodular size, margin, shape, echo texture, echogenicity, cystic change, vascularity and local invasion on sonography between ATC and PTL groups. Echogenic strands, markedly hypoechoic and enhanced posterior echo were seen more frequently in PTL group (92.6%, 92.6%, and 85.2%, respectively) than those in ATC group (6.7%, 60.0%, and 33.3%, respectively) (P<0.05), and calcification was seen more frequently in ATC group (80.0%) than in PTL group (0%) (P<0.001). Three ultrasound patterns were observed for PTL including diffuse type (25.9%), nodular type (48.2%) and mixed type (25.9%), while all ATC cases presented with nodular type (100.0%). Associated Hashimoto's thyroiditis occurred more frequently in PTL group (59.3%) than in ATC group (20.0%) (P=0.023)., Conclusions: Certain sonographic features as a markedly hypoechogenicity, the presence of an enhanced posterior echo and linear echogenic strands, lack of calcification and associated Hashimoto's thyroiditis were valuable for distinguishing PTL from ATC. In contrast, heterogeneous echogenicity, uncircumscribed margin, irregular shape, and vascular pattern were not specific features for differential diagnosis., Competing Interests: Conflicts of Interest: The authors have no conflicts of interest to declare.

Background: Contrast enhanced ultrasound (CEUS) is an effective way to evaluate the distribution of micro vessels in organs with little invasiveness. The qualitative evaluation and differential diagnosis of lymph node is essential for a number of clinical situations, including appropriate examination selection, oncologic staging, therapy and prognosis beyond diagnosis itself. The purpose of this study is to investigate the contribution of characterization of cervical lymphadenopathies on CEUS as an indication for lymph node puncture biopsy., Methods: Records of 157 lymph nodes from 103 patients who had undergone CEUS examination were studied retrospectively, and enhancement patterns and characteristics were evaluated. The diagnoses obtained by means of core-needle biopsy examination or surgical removal, or patients were closely followed-up for at least 6 months. Of the lymph nodes examined, 94 were benign (48 lymphadenitis and 46 tuberculosis) and 63 were malignant (55 metastases and 8 lymphomas). The vascular characterization of lymph nodes was compared with results obtained by pathologic examination., Results: The study using CEUS showed 55 (54.5%) cases of "peripheral" enhancement in group A and 47 (83.9%) cases of "hilar normal or activated" in group B. Inhomogeneous "spotted or cycle-like" enhancement in the equilibrium phase was seen in 80 (79.2%) cases of group A and only 11 (19.6%) cases of group B. The specificity, sensitivity and accuracy of CEUS examination result as an indication for puncture biopsy were 80.4%, 81.2% and 80.9%, respectively., Conclusions: Centripetal perfusion in the early arterial phase or inhomogeneous spotted or cycle-like enhancement in the equilibrium phase of the cervical lymph nodes during CEUS can be used as an indication for core-needle biopsy with a high degree of accuracy. Conversely, for lymph nodes with more variable appearances, surgical removal or closely followed-up of nodes may be more appropriate., Competing Interests: Conflicts of Interest: The authors have no conflicts of interest to declare.

The medical literature is replete with the maxim 'primum non nocere', cautioning health care providers to avoid doing any harm to human subjects in their delivery of medical care. Sodium hypochlorite (NaOCl) is a well-established irrigant for root canal treatment because of its antimicrobial and organic tissue remnant dissolution capability. However, little is known about the deleterious effect of this strong oxidizing agent on the integrity of human mineralized dentin. Iatrogenically-induced loss of dentin integrity may precipitate post-treatment root fracture and has potential medico-legal complications. In the present work, transmission electron microscopy provided evidence for collagen destruction in the surface/subsurface of dentin treated with high NaOCl concentrations and long contact times. Size exclusion chromatography showed that the hypochlorite anion, because of its small size, penetrated the water compartments of apatite-encapsulated collagen fibrils, degraded the collagen molecules and produced a 25-35µm thick, non-uniform "ghost mineral layer" with enlarged, coalesced dentinal tubules and their lateral branches. Fourier transform-infrared spectroscopy identified increases in apatite/collagen ratio in NaOCl-treated dentin. The apatite-rich, collagen-sparse dentin matrix that remained after NaOCl treatment is more brittle, as shown by the reductions in flexural strength. Understanding the deleterious effects of NaOCl on mineralized dentin enables one to balance the risks and benefits in using high NaOCl concentrations for lengthy periods in root canal debridement. Delineating the mechanism responsible for such a phenomenon enables high molecular weight, polymeric antimicrobial and tissue dissolution irrigants to be designed that abides by the maxim of 'primum non nocere' in contemporary medical practices., Statement of Significance: The antimicrobial and tissue-dissolution capacities of NaOCl render it a well-accepted agent for root canal debridement. These highly desirable properties, however, appear to be intertwined with the untoward effect of collagen matrix degradation within mineralized dentin. Because of its small size, the hypochlorite anion is capable of infiltrating mineralized collagen and destroying the collagen fibrils, producing a mineral-rich, collagen sparse ghost mineral matrix with reduced flexural strength. Findings from the present work challenge the biosafety of NaOCl when it is used in high concentrations and for lengthy time periods during root canal treatment, and laid the background work for future biomaterials design in debridement of the canal space., (Published by Elsevier Ltd.)

Limitations associated with wet-bonding led to the recent development of a selective demineralization strategy in which dentin was etched with a reduced concentration of phosphoric acid to create exclusive extrafibrillar demineralization of the collagen matrix. However, the use of acidic conditioners removes calcium via diffusion of very small hydronium ions into the intrafibrillar collagen water compartments. This defeats the purpose of limiting the conditioner to the extrafibrillar space to create a collagen matrix containing only intrafibrillar minerals to prevent collapse of the collagen matrix. The present work examined the use of polymeric chelators (the sodium salt of polyacrylic acid) of different molecular weights to selectively demineralize extrafibrillar dentin. These polymeric chelators exhibit different affinities for calcium ions (isothermal titration calorimetry), penetrated intrafibrillar dentin collagen to different extents based on their molecular sizes (modified size-exclusion chromatography), and preserve the dynamic mechanical properties of mineralized dentin more favorably compared with completely demineralized phosphoric acid-etched dentin (nanoscopical dynamic mechanical analysis). Scanning and transmission electron microscopy provided evidence for retention of intrafibrillar minerals in dentin surfaces conditioned with polymeric chelators. Microtensile bond strengths to wet-bonded and dry-bonded dentin conditioned with these polymeric chelators showed that the use of sodium salts of polyacrylic acid for chelating dentin prior to bonding did not result in significant decline in resin-dentin bond strength. Taken together, the findings led to the conclusion that a chelate-and-rinse conditioning technique based on extrafibrillar collagen demineralization bridges the gap between wet and dry dentin bonding., Statement of Significance: The chelate-and-rinse dental adhesive bonding concept differentiates from previous research in that it is based on the size-exclusion characteristics of fibrillar collagen; molecules larger than 40kDa are prevented from accessing the intrafibrillar water compartments of the collagen fibrils. Using this chelate-and-rinse extrafibrillar calcium chelation concept, collagen fibrils with retained intrafibrillar minerals will not collapse upon air-drying. This enables adhesive infiltration into the mineral-depleted extrafibrillar spaces without relying on wet-bonding. By bridging the gap between wet and dry dentine bonding, the chelate-and-rinse concept introduces additional insight to the field by preventing exposure of endogenous proteases via preservation of the intrafibrillar minerals within a collagen matrix. If successfully validated, this should help prevent degradation of resin-dentine bonds by collagenolytic enzymes., (Published by Elsevier Ltd.)

Four new complexes, [Co(dmbpy)2(dca)2]·CH3OH (1), [Ni(dmbpy)2(dca)2]·CH3OH (2), [Zn(dmbpy)2(dca)2]·(3) and [Cu(dmbpy)2(OH)2]·5H2O (4) (dca=dicyanamide), derived from 4,4'-dimethyl-2,2'-bipyridine (dmbpy) have been synthesized and characterized by elemental analysis, TGA and single-crystal X-ray diffraction. Crystal structures and Hirshfeld surfaces analysis revealed that the complexes 1-3 were mainly supported by OH⋯N, CH⋯N and π⋯π intermolecular interactions, and for complex 4, the uncoordinated water molecules play a key role in the construction of the 3D stacking motif. UV spectrum measurements demonstrate that all of the complexes show typical metal to ligand charge transfer (MLCT) absorption bands between 301 and 306nm. Moreover, after complexation, the absorption maximum bands about intraligand π→π* transitions similarly show slightly red shift compared to dmbpy ligand, consisting with the DFT calculations., (Copyright © 2016 Elsevier B.V. All rights reserved.)

Introduction: Thorough cleaning and shaping of root canals are essential for periapical healing. Restoration of endodontically treated teeth is also required for them to function and prevent coronal leakage. This study compared the impact of the quality of root canal treatment versus the quality of coronal restoration in treatment outcomes., Methods: Literature search was conducted using the search terms "coronal restoration," "root canal," "periapical status," and "quality." Articles that evaluated the effect of the quality of root filling and coronal restoration or both on the success of root canal treatment were selected. Nine articles were identified and were reviewed by 3 investigators. Data were collected based on predetermined criteria. Percentages of teeth without apical periodontitis were recorded for each category: adequate root canal treatment (AE), inadequate root canal treatment (IE), adequate restoration (AR), and inadequate restoration (IR). Data were analyzed using meta-analysis for odds ratios (ORs)., Results: After adjusting for significant covariates to reduce heterogeneity, the results were combined to obtain pooled estimates of the common OR for the comparison of AR/AE versus AR/IE (OR = 2.734; 95% confidence interval [CI], 2.61-2.88; P < .001) and AR/AE versus IR/AE (OR = 2.808; 95% CI, 2.64-2.97; P < .001)., Conclusions: On the basis of the current best available evidence, the odds for healing of apical periodontitis increase with both adequate root canal treatment and adequate restorative treatment. Although poorer clinical outcomes may be expected with adequate root filling-inadequate coronal restoration and inadequate root filling-adequate coronal restoration, there is no significant difference in the odds of healing between these 2 combinations., (Copyright © 2011 American Association of Endodontists. Published by Elsevier Inc. All rights reserved.)

Immobilization of phosphoproteins on a collagen matrix is important for the induction of intrafibrillar apatite mineralization. Unlike phosphate esters, polyphosphonic acid has no reactive sites for covalent binding to collagen amine groups. Binding of poly(vinyl phosphonic acid) (PVPA), a biomimetic templating analog of matrix phosphoproteins, to collagen was found to be electrostatic in nature. Thus, an alternative retention mechanism was designed for immobilization of PVPA on collagen by cross-linking the latter with carbodiimide (EDC). This mechanism is based on the principle of size exclusion entrapment of PVPA molecules within the internal water compartments of collagen. By cross-linking collagen with EDC, a zero length cross-linking agent, the sieving property of collagen is increased, enabling the PVPA to be immobilized within the collagen. The absence of covalent cross-linking between PVPA and collagen was confirmed by Fourier transform infrared spectroscopy. Based on these results, a concentration range for immobilized PVPA to template intrafibrillar apatite deposition was established and validated using a single layer reconstituted type I collagen mineralization model. In the presence of a polyacrylic acid-containing mineralization medium optimal intrafibrillar mineralization of the EDC-cross-linked collagen was achieved using 500 and 1000 μg ml⁻¹ PVPA. The mineralized fibrils exhibited a hierarchical order of intrafibrillar mineral infiltration, as manifested by the appearance of electron-dense periodicity within unstained fibrils. Understanding the basic processes in intrafibrillar mineralization of reconstituted collagen creates opportunities for the design of tissue engineering materials for hard tissue repair and regeneration., (Copyright © 2010 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.)

Objective: This study evaluated the ability of benzalkonium chloride (BAC) to bind to dentine and to inhibit soluble recombinant MMPs and bound dentine matrix metalloproteinases (MMPs)., Methods: Dentine powder was prepared from extracted human molars. Half was left mineralized; the other half was completely demineralized. The binding of BAC to dentine powder was followed by measuring changes in the supernatant concentration using UV spectrometry. The inhibitory effects of BAC on rhMMP-2, -8 and -9 were followed using a commercially available in vitro proteolytic assay. Matrix-bound endogenous MMP-activity was evaluated in completely demineralized beams. Each beam was either dipped into BAC and then dropped into 1 mL of a complete medium (CM) or they were placed in 1 mL of CM containing BAC for 30 days. After 30 days, changes in the dry mass of the beams or in the hydroxyproline (HYP) content of hydrolysates of the media were quantitated as indirect measures of matrix collagen hydrolysis by MMPs., Results: Demineralized dentine powder took up 10-times more BAC than did mineralized powder. Water rinsing removed about 50% of the bound BAC, whilst rinsing with 0.5M NaCl removed more than 90% of the bound BAC. BAC concentrations 0.5wt% produced 100% inhibition of soluble recombinant MMP-2, -8 or -9, and inhibited matrix-bound MMPs between 55 and 66% when measured as mass loss or 76-81% when measured as solubilization of collagen peptide fragments., Conclusions: BAC is effective at inhibiting both soluble recombinant MMPs and matrix-bound dentine MMPs in the absence of resins., (Copyright © 2010 Elsevier Ltd. All rights reserved.)

Objectives: Type I collagen alone cannot initiate tissue mineralization. Sodium trimetaphosphate (STMP) is frequently employed as a chemical phosphorylating reagent in the food industry. This study examined the feasibility of using STMP as a functional analog of matrix phosphoproteins for biomimetic remineralization of resin-bonded dentin., Methods: Equilibrium adsorption and desorption studies of STMP were performed using demineralized dentin powder (DDP). Interaction between STMP and DDP was examined using Fourier transform-infrared spectroscopy. Based on those results, a bio-inspired mineralization scheme was developed for chemical phosphorylation of acid-etched dentin with STMP, followed by infiltration of the STMP-treated collagen matrix with two etch-and-rinse adhesives. Resin-dentin interfaces were remineralized in a Portland cement-simulated body fluid system, with or without the use of polyacrylic acid (PAA) as a dual biomimetic analog. Remineralized resin-dentin interfaces were examined unstained using transmission electron microscopy., Results: Analysis of saturation binding curves revealed the presence of irreversible phosphate group binding sites on the surface of the DDP. FT-IR provided additional evidence of chemical interaction between STMP and DDP, with increased in the peak intensities of the PO and P-O-C stretching modes. Those peaks returned to their original intensities after alkaline phosphatase treatment. Evidence of intrafibrillar apatite formation could be seen in incompletely resin-infiltrated, STMP-phosphorylated collagen matrices only when PAA was present in the SBF., Significance: These results reinforce the importance of PAA for sequestration of amorphous calcium phosphate nanoprecursors in the biomimetic remineralization scheme. They also highlight the role of STMP as a templating analog of dentin matrix phosphoproteins for inducing intrafibrillar remineralization of apatite nanocrystals within the collagen matrix of incompletely resin-infiltrated dentin., (Copyright © 2010 Academy of Dental Materials. Published by Elsevier Ltd. All rights reserved.)

The complex morphologies of mineralised collagen fibrils are regulated through interactions between the collagen matrix and non-collagenous extracellular proteins. In the present study, polyvinylphosphonic acid, a biomimetic analogue of matrix phosphoproteins, was synthesised and confirmed with FTIR and NMR. Biomimetic mineralisation of reconstituted collagen fibrils devoid of natural non-collagenous proteins was demonstrated with TEM using a Portland cement-containing resin composite and a phosphate-containing fluid in the presence of polyacrylic acid as sequestration, and polyvinylphosphonic acid as templating matrix protein analogues. In the presence of these dual biomimetic analogues in the mineralisation medium, intrafibrillar and extrafibrillar mineralisation via bottom-up nanoparticle assembly based on the non-classical crystallisation pathway could be identified. Conversely, only large mineral spheres with no preferred association with collagen fibrils were observed in the absence of biomimetic analogues in the medium. Mineral phases were evident within the collagen fibrils as early as 4 h after the initially-formed amorphous calcium phosphate nanoprecursors were transformed into apatite nanocrystals. Selected area electron diffraction patterns of highly mineralised collagen fibrils were nearly identical to those of natural bone, with apatite crystallites preferentially aligned along the collagen fibril axes., (Published by Elsevier Ltd.)

This study examined changes in elastic modulus, mineral density and ultrastructure of resin-infiltrated dentin after biomimetic remineralization. Sixty demineralized dentin beams were infiltrated with Clearfil Tri-S Bond, One-Step or Prime&Bond NT. They were immersed in simulated body fluid (SBF) for 1 week to maximize water sorption before determining the baseline elastic moduli. For each adhesive (N = 20) half of the beams remained immersed in SBF (control). The rest were immersed in a biomimetic remineralization medium. The elastic moduli were measured weekly for 15 additional weeks. Representative remineralized specimens were evaluated by X-ray microtomography and transmission electron microscopy (TEM). The elastic moduli of control resin-infiltrated dentin remained consistently low, while those immersed in the biomimetic remineralization medium increased by 55-118% after 4 months. X-ray microtomography of the remineralized specimens revealed decreases in mineral density from the beam surface to the beam core that were indicative of external mineral aggregation and internal mineral deposition. Interfibrillar and intrafibrillar remineralization of resin-sparse intertubular dentin were seen under TEM, together with remineralized peritubular dentin. Biomimetic remineralization occurs by diffusion of nanoprecursors and biomimetic analogs in completely demineralized resin-infiltrated dentin and proceeds without the contribution of materials released from a mineralized dentin base., (Copyright 2009 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.)

Introduction: This study examined the effect of vapor lock on canal debridement efficacy by testing the null hypothesis that there is no difference between a "closed" and an "open" system design in smear layer and debris removal by using a side-vented needle for irrigant delivery., Methods: Roots in the closed system were sealed with hot glue and embedded in polyvinylsiloxane to restrict fluid flow through the apical foramen during cleaning and shaping. For the open system, the apical foramen was enlarged and connected to the external environment via a channel within the polyvinylsiloxane to permit unrestricted fluid flow. Smear and debris scores were evaluated by using scanning electron microscopy and analyzed by using Cochran-Mantel-Haenszel statistic., Results: No difference in smear scores was detected between the 2 systems at all canal levels. Significant differences in debris scores between the 2 systems were found at each canal level: coronal (P < .001), middle (P < .001), and apical (P < .001)., Conclusions: The null hypothesis was rejected; presence of an apical vapor lock effect adversely affects debridement efficacy. Thus, studies with unspecified or questionable mechanisms to restrict fluid flow through the apical foramen have to be interpreted with caution., (Copyright (c) 2010 American Association of Endodontists. Published by Elsevier Inc. All rights reserved.)

Introduction: Four generations of methacrylate resin-based sealers have been available commercially. Three of these were introduced during the last 5 years when the concept of simultaneous bonding of root canal sealers to root filling materials and dentin was popularized., Methods: This article presents an overview of methacrylate resin-based sealers, with the objectives of clarifying the behavior of these materials and delineating their limitations in clinical application., Results: The first generation sealer was introduced in the mid-1970s. The initial enthusiasm associated with its use eventually diminished as a result of its suboptimal physical, biologic, and clinical properties. With advances in self-etching adhesive technology acquired from adhesive dentistry, methacrylate resin-based sealers were reintroduced in the beginning of the 21st century to support the introduction of bondable root canal filling materials. Three different generations of these sealers have since been available commercially. Although some in vitro studies on the sealing ability, self-etching potential, biocompatibility, and removability of the sealers showed better potential over conventional nonbonding sealers, accomplishing the ideal goal of a monoblock in the root canal space with these materials is still regarded as a major challenge., Conclusions: On the basis of the in vitro and in vivo data available to date, there appears to be no clear benefit with the use of methacrylate resin-based sealers in conjunction with adhesive root filling materials at this point in their development., (Copyright (c) 2010 American Association of Endodontists. Published by Elsevier Inc. All rights reserved.)

Objective: This study tested the hypothesis that the use of ethylenediamine tetraacetic acid (EDTA) as a final irrigant causes canal wall erosion only after prolonged use of 5.25% sodium hypochlorite (NaOCl) as the initial irrigant., Methods: Two irrigation protocols were employed: (1) 5.25% NaOCl as the initial irrigant for 10 min and 17% EDTA as the final irrigant for 2 min; and (2) 5.25% NaOCl for 60 min and 17% EDTA for 2 min. Flexural strengths of dentine beams prepared from human mid-coronal dentine were evaluated using a miniature three-point bending device after they were irrigated with either protocol. Transmission electron microscopy was used to examine the conditions of instrumented canal walls irrigated with either protocol after they were bonded with methacrylate resin-based sealers., Results: Immersion of dentine beams in NaOCl for 60 min instead of 10 min prior to the use of EDTA resulted in a significant (p<0.001) decline in flexural strength. For both NaOCl initial rinsing times, a 2-min final irrigation with EDTA created similar 0.5 microm thick demineralisation fronts. However, extensive surface and subsurface erosion of radicular dentine was seen only when the dentine was immersed in NaOCl for 60 min., Conclusion: The apparent aggressiveness of EDTA in causing canal wall erosion is attributed to the prolonged use of NaOCl. The associated decline in dentine flexural strength has potential clinical relevance when thin pulp chamber dentine is immersed in NaOCl for lengthy periods during canal instrumentation. This may render root-treated teeth more prone to vertical fracture., (Copyright 2009 Elsevier Ltd. All rights reserved.)

Introduction: Effective irrigant delivery and agitation are prerequisites for successful endodontic treatment., Methods: This article presents an overview of the irrigant agitation methods currently available and their debridement efficacy., Results: Technological advances during the last decade have brought to fruition new agitation devices that rely on various mechanisms of irrigant transfer, soft tissue debridement, and, depending on treatment philosophy, removal of smear layers. These devices might be divided into the manual and machine-assisted agitation systems. Overall, they appear to have resulted in improved canal cleanliness when compared with conventional syringe needle irrigation. Despite the plethora of in vitro studies, no well-controlled study is available. This raises imperative concerns on the need for studies that could more effectively evaluate specific irrigation methods by using standardized debris or biofilm models. In addition, no evidence-based study is available to date that attempts to correlate the clinical efficacy of these devices with improved treatment outcomes. Thus, the question of whether these devices are really necessary remains unresolved. There also appears to be the need to refocus from a practice management perspective on how these devices are perceived by clinicians in terms of their practicality and ease of use., Conclusions: Understanding these fundamental issues is crucial for clinical scientists to improve the design and user-friendliness of future generations of irrigant agitation systems and for manufacturers' contentions that these systems play a pivotal role in contemporary endodontics.

Introduction: Smearing of unset root canal sealers over the pulp chamber dentin may adversely affect bonding of self-etching adhesives and jeopardize their coronal sealing potential. This study examined the influence of different sealer removal protocols on the microtensile bond strengths of two self-etching adhesives to AH Plus-contaminated dentin., Methods: Coronal dentin surfaces were prepared from extracted human third molars. In the positive control groups, these surfaces were not contaminated with sealer and were bonded with Clearfil SE Bond or Clearfil Tri-S Bond. For the experimental groups, dentin surfaces were contaminated with AH Plus and wiped with either dry cotton pellets, cotton pellets saturated with ethanol, or cotton pellets saturated with Endosolv R followed by rinsing the dissolved sealer with water prior to bonding with the two adhesives. Bonded specimens were sectioned into resin-dentin beams for microtensile bond strength evaluation. Additional specimens were prepared for transmission electron microscopy to examine the ultrastructure and nanoleakage within the hybrid layers., Results: For both adhesives, microtensile bond strengths significantly declined when the sealer was removed with dry cotton pellets or cotton pellets saturated with ethanol. Only the Endosolv R/water sealer removal protocol restored tensile bond strengths to those of the uncontaminated positive controls without adversely affecting hybrid layer formation in intact dentin or increasing nanoleakage within the resin-dentin interfaces., Conclusion: The Endosolv R sealer removal protocol appears to be effective in preventing the deterioration of bond strengths of the two self-etching adhesives to AH Plus-contaminated dentin and warrants further clinical investigation.

Objective: To investigate the prevalence and configuration of the isthmuses in the apical 6 mm of the mesial and distal roots of Chinese mandibular first molar by means of micro-computed tomography., Methods: Thirty-six extracted human mandibular first molars were selected. Specimens were subject to micro-CT and a slice thickness of 30 microm was obtained in the apical 6 mm of the roots examined. The number of sections showing isthmuses at each apical level was recorded. Three-dimensional images of isthmuses of mandibular first molars were reconstructed and observed., Results: The mesial roots of human mandibular first molars had a high incidence of isthmus. The isthmus incidence was greatest 4-6 mm from the apex in human mandibular first molar, with prevalence figures of 49.5%-66.1% and 17.3%-17.8% in mesial and distal roots, respectively. The chi-square test indicated a significant difference in the distribution of isthmuses between the two roots (P < 0.01)., Conclusions: The mesial roots of human mandibular first molars have a high incidence of isthmus, which may have clinical implications especially when surgical endodontics is performed on the mesial roots of mandibular molars.

Aim: To evaluate the efficacy of the ProTaper Universal rotary retreatment system for gutta-percha (GP) removal from root canals., Methodology: Root canals of 60 extracted human maxillary anterior teeth were prepared and filled with laterally condensed GP and AH Plus sealer. Teeth were divided into three groups: group A--GP removal completed with the ProTaper Universal rotary retreatment system and with further canal repreparation accomplished with ProTaper Universal rotary instruments; group B--GP removal was completed using Gates Glidden drills and Hedström files with chloroform as a solvent, followed with further canal repreparation with ProTaper Universal rotary instruments; group C--the same as group B for GP removal with further canal preparation with stainless steel K-flex files (Kerr). The operating time was recorded. Teeth were rendered transparent for the evaluation of the area of remaining GP/sealer in bucco-lingual and mesial-distal directions. Statistical analysis was performed by using repeated measures analysis of variance and anova. Results The ProTaper Universal technique (group A) resulted in a smaller percentage of canal area covered by residual GP/sealer than in groups B and C, with a significant difference between groups A and C (P < 0.05). Mean operating time for group A was 6.73 min, which was significantly shorter (P < 0.05) than group B (10.86 min) and group C (13.52 min)., Conclusions: In this laboratory study all test techniques left GP/sealer remnants within the root canal. The ProTaper Universal rotary retreatment system proved to be an efficient method of removing GP and sealer from maxillary anterior teeth.