Identification and characterization of ACR gene family in maize for salt stress tolerance.

Background: Members of the ACR gene family are commonly involved in various physiological processes, including amino acid metabolism and stress responses. In recent decades, significant progress has been made in the study of ACR genes in plants. However, little is known about their characteristics and function in maize. Methods: In this study, ACR genes were identified from the maize genome, and their molecular characteristics, gene structure, gene evolution, gene collinearity analysis, cis-acting elements were analyzed. qRT-PCR technology was used to verify the expression patterns of the ZmACR gene family in different tissues under salt stress. In addition, Ectopic expression technique of ZmACR5 in Arabidopsis thaliana was utilized to identify its role in response to salt stress. Results: A total of 28 ZmACR genes were identified, and their molecular characteristics were extensively described. Two gene pairs arising from segmented replication events were detected in maize, and 18 collinear gene pairs were detected between maize and 3 other species. Through phylogenetic analysis, three subgroups were revealed, demonstrating distinct divergence between monocotyledonous and dicotyledonous plants. Analysis of ZmACR cis-acting elements revealed the optional involvement of ZmACR genes in light response, hormone response and stress resistance. Expression analysis of 8 ZmACR genes under salt treatment clearly revealed their role in the response to salt stress. Ectopic overexpression of ZmACR5 in Arabidopsis notably reduced salt tolerance compared to that of the wild type under salt treatment, suggesting that ZmACR5 has a negative role in the response to salt stress. Conclusion: Taken together, these findings confirmed the involvement of ZmACR genes in regulating salt stress and contributed significantly to our understanding of the molecular function of ACR genes in maize, facilitating further research in this field.

Genome-wide identification and analysis of the cotton ALDH gene family.

BACKGROUND: Aldehyde dehydrogenases (ALDHs) are a family of enzymes that catalyze the oxidation of aldehyde molecules into the corresponding carboxylic acid, regulate the balance of aldehydes and protect plants from the poisoning caused by excessive accumulation of aldehydes; however, this gene family has rarely been studied in cotton. RESULTS: In the present study, genome-wide identification was performed, and a total of 114 ALDH family members were found in three cotton species, Gossypium hirsutum, Gossypium arboreum and Gossypium raimondii. The ALDH genes were divided into six subgroups by evolutionary analysis. ALDH genes in the same subgroup showed similar gene structures and conserved motifs, but some genes showed significant differences, which may result in functional differences. Chromosomal location analysis and selective pressure analysis revealed that the ALDH gene family had experienced many fragment duplication events. Cis-acting element analysis revealed that this gene family may be involved in the response to various biotic and abiotic stresses. The RT‒qPCR results showed that the expression levels of some members of this gene family were significantly increased under salt stress conditions. Gohir.A11G040800 and Gohir.D06G046200 were subjected to virus-induced gene silencing (VIGS) experiments, and the sensitivity of the silenced plants to salt stress was significantly greater than that of the negative control plants, suggesting that Gohir.A11G040800 and Gohir.D06G046200 may be involved in the response of cotton to salt stress. CONCLUSIONS: In total, 114 ALDH genes were identified in three Gossypium species by a series of bioinformatics analysis. Gene silencing of the ALDH genes of G. hirsutum revealed that ALDH plays an important role in the response of cotton to salt stress.

An analysis of lncRNAs related to fiber quality and the discovery of their target genes in a Gossypium hirsutum line with Gossypium mustelinum introgression.

KEY MESSAGE: Analysis of fiber quality lncRNAs and their target genes from a pair of Gossypium mustelinum near-isogenic lines provide new prospects for improving the fiber quality of Upland cotton. Long noncoding RNAs (lncRNAs) are an important part of genome transcription and play roles in a wide range of biological processes in plants. In this research, a pair of near-isogenic cotton lines, namely, a Gossypium mustelinum introgression line (IL9) with outstanding fiber quality and its recurrent Upland cotton parent (PD94042), were used as the experimental materials. Cotton fibers were selected for lncRNA sequencing at 17 and 21 days post-anthesis. A total of 2693 differentially expressed genes were identified. In total, 5841 lncRNAs were ultimately screened, from which 163 differentially expressed lncRNAs were identified. Target genes of the lncRNAs were predicted by two different methods: cis and trans. Some of the target genes were related to cell components, membrane components, plant hormone signal transduction and catalytic metabolism, and the results indicated that there might also be important effects on the development of fiber. Four differentially expressed target genes related to fiber quality (Gomus.D05G015100, Gomus.A05G281300, Gomus.A12G023400 and Gomus.A10G226800) were screened through gene function annotation, and the functions of these four genes were verified through virus-induced gene silencing (VIGS). Compared to the negative controls, plants in which any of these four genes were silenced showed significant reductions in fiber strength. In addition, the plants in which the Gomus.A12G023400 gene was silenced showed a significant reduction in fiber uniformity, whereas the plants in which Gomus.A05G281300 was silenced showed a significant increase in fiber fineness as measured via micronaire. Our results showed that these genes play different roles during fiber development, impacting fiber quality.

Distinct Microbial Community of Accumulated Biofilm in Dental Unit Waterlines of Different Specialties.

The contamination of dental unit waterlines (DUWLs) is a serious problem and directly affects the dental care. This study aims to explore the microbial community of biofilm in DUWL from different specialties and investigate the associated factors. A total of 36 biofilm samples from 18 DUWL of six specialties (i.e., prosthodontics, orthodontics, pediatrics, endodontics, oral surgery, and periodontics) at two time points (i.e., before and after daily dental practice) were collected with a novel method. Genomic DNA of samples was extracted, and then 16S ribosomal DNA (rDNA) (V3-V4 regions) and ITS2 gene were amplified and sequenced. Kruskal-Wallis and Wilcoxon rank test were adopted for statistical analysis. Microbial community with high diversity of bacteria (631 genera), fungi (193 genera), and viridiplantae was detected in the biofilm samples. Proteobacteria was the dominant bacteria (representing over 65.74-95.98% of the total sequences), and the dominant fungi was Ascomycota (93.9-99.3%). Microorganisms belonging to multiple genera involved in human diseases were detected including 25 genera of bacteria and eight genera of fungi, with relative abundance of six genera over 1% (i.e., Acinetobacter, Pseudomonas, Enterobacter, Aspergillus, Candida, and Penicillium). The biofilm microbiome may be influenced by the characteristics of dental specialty and routine work to some extent. The age of dental chair unit and overall number of patients had the strongest impact on the overall bacteria composition, and the effect of daily dental practices (associated with number of patients and dental specialty) on the fungi composition was the greatest. For the first time, biofilm in DUWL related to dental specialty was comprehensively evaluated, with more abundance of bacterial and fungal communities than in water samples. Biofilm accumulation with daily work and multiple kinds of opportunistic pathogen emphasized the infectious risk with dental care and the importance of biofilm control.

Synthesis of a grape-like conductive carbon black/Ag hybrid as the conductive filler for soft silicone rubber.

Conductive silicone rubber (CSR) is an outstanding stretchable conductive composite due to its excellent mechanical properties and stable conductivity. In this paper, silver nanoparticles were deposited on carbon black (CB) through a reduction reaction. The uniform dispersion of silver particles on the surface of CB as well as the grape-like branch structure of hybrid particles was formed by the condensation reaction of the hydroxyl groups of CB with (3-mercaptopropyl) trimethoxysilane (KH-590), along with the interattraction between sulfhydryl groups of KH-590 and silver ions. This sulfhydryl modified conductive carbon black/Ag hybrid filler (SMCB@Ag) avoided the high processing viscosity of CSR caused by the hydroxyl groups of CB. The percolation threshold of CSR made from SMCB@Ag was 5.5 wt% according to the percolation equation. With the addition amount of SMCB@Ag increasing to 10 wt%, the conductivity of CSR increased from 10-5 to about 101. Moreover, the conductivity of this CSR showed excellent stability with extension of storage time and increase of stretching-recovery cycles.

Alterations in Oral-Nasal-Pharyngeal Microbiota and Salivary Proteins in Mouth-Breathing Children.

Mouth breathing induces a series of diseases, while the influence on microbiota of oral cavity and salivary proteins remains unknown. In this study, for the first time, profiles of oral-nasal-pharyngeal microbiota among mouth-breathing children (MB group, n = 10) were compared with paired nose-breathing children (NB group, n = 10) using 16S ribosomal DNA (rDNA) (V3-V4 region) high-throughput sequencing. The differentially expressed salivary proteins were revealed using label-free quantification (LFQ) method, and their associations with bacterial abundance were measured by canonical correspondence analysis (CCA). The overall bacterial profiles differed between the two groups, and the differences were related to the duration of mouth breathing. The diversity of oral-pharyngeal microbiota was significantly higher, and the nasal-pharyngeal species tended to be consistent (unweighted UniFrac, p = 0.38) in the MB group. Opportunistic pathogens were higher in relative abundance as follows: Acinetobacter in the anterior supragingival plaque, Neisseria in unstimulated saliva, Streptococcus pneumoniae in the pharynx, and Stenotrophomonas in the nostrils. The expression level of oxidative-stress-related salivary proteins (lactoylglutathione lyase and peroxiredoxin-5) were upregulated, while immune-related proteins (integrin alpha-M and proteasome subunit alpha type-1) were downregulated in MB group. The differentially expressed proteins were associated with specific bacteria, indicating their potentials as candidate biomarkers for the diagnosis, putatively early intervention, and therapeutic target of mouth breathing. This study showed that mouth breathing influences the oral-nasal-pharyngeal microbiota and enriches certain pathogens, accompanied with the alterations in the salivary environment. Further research on the pathological mechanisms and dynamic changes in longitudinal studies are warranted.

Casein phosphopeptide combined with fluoride enhances the inhibitory effect on initial adhesion of Streptococcus mutans to the saliva-coated hydroxyapatite disc.

BACKGROUND: Recent preventive strategies for dental caries focus on targeting the mechanisms underlying biofilm formation, including the inhibition of bacterial adhesion. A promising approach to prevent bacterial adhesion is to modify the composition of acquired salivary pellicle. This in vitro study investigated the effect and possible underlying mechanism of pellicle modification by casein phosphopeptide (CPP) on Streptococcus mutans (S. mutans) initial adhesion, and the impact of fluoride on the efficacy of CPP. METHODS: The salivary pellicle-coated hydroxyapatite (s-HA) discs were treated with phosphate buffered saline (negative control), heat-inactivated 2.5% CPP (heat-inactivated CPP), 2.5% CPP (CPP) or 2.5% CPP supplemented with 900 ppm fluoride (CPP + F). After cultivation of S. mutans for 30 min and 2 h, the adherent bacteria were visualized by scanning electron microscopy (SEM) and quantitatively evaluated using the plate count method. Confocal laser scanning microscopy (CLSM) was used to evaluate the proportions of total and dead S. mutans. The concentrations of total, free, and bound calcium and fluoride in the CPP and fluoride-doped CPP solutions were determined. The water contact angle and zeta potential of s-HA with and without modification were measured. The data were statistically analyzed using one-way ANOVA followed by a Turkey post hoc multiple comparison test. RESULTS: Compared to the negative control group, the amount of adherent S. mutans significantly reduced in the CPP and CPP + F groups, and was lowest in the CPP + F group. CLSM analysis showed that there was no statistically significant difference in the proportion of dead S. mutans between the four groups. Water contact angle and zeta potential of s-HA surface significantly decreased in the CPP and CPP + F groups as compared to the negative control group, and both were lowest in the CPP + F group. CONCLUSIONS: Pellicle modification by CPP inhibited S. mutans initial adhesion to s-HA, possibly by reducing hydrophobicity and negative charge of the s-HA surface, and incorporating fluoride into CPP further enhanced the anti-adhesion effect.

Proteomic analysis of the effects of CSF-1 and IL-1α on dental follicle cells.

Tooth eruption is a complex physiological process involving both osteogenesis and bone resorption. Signals from the dental follicle (DF) regulate bone remodeling during tooth eruption. Interleukin-1α (IL-1α) may be the initial promoter of tooth eruption, whereas colony­stimulating factor­1 (CSF­1) may attract monocytes into the DF and stimulate osteoclast differentiation. In the present study, differential proteomics was employed to explore protein changes in rat DF cells (DFCs) under the effects of CSF­1 and IL­1α. A total of 47 protein spots were differentially expressed in rat DFCs, and 40 protein spots were identified by MALDI­TOF­MS. The identified proteins were grouped into functional categories including cytoskeletal proteins, metal­binding proteins, proteins involved in secretion and degradation, cell cycle proteins and stress proteins. In IL­1α­induced rat DFCs, 31 proteins were upregulated compared with the control and included heat shock protein ß­1 (HSP25, also known as HSP27/HSPß1), vimentin, TMEM43, the GTP­binding protein Rab­3D, 6­pyruvoyl tetrahydrobiopterin synthase and actin. In total, 7 proteins were downregulated, including serum albumin, GIPC1, DNA primase large subunit, cullin­5 and cyclin­G1. In CSF­1­induced rat DFCs, 3 proteins were upregulated and 7 proteins were downregulated when compared with the controls. The upregulated proteins included the GTP­binding protein Rab­3D and α­actin. The downregulated proteins included cullin­5, serum albumin, PDZ domain­containing protein and cyclin­G1. The differential expression of vimentin, actin, HSP25 and Rab­3D was verified by western blotting and reverse transcription­quantitative polymerase chain reaction analyses. The present findings provide an insight into the mechanisms involved in tooth eruption.

Mineralising and antibacterial effects of modified calcium phosphate treatment on human root cementum.

BACKGROUND: Aging population will lead to the increase of incidence of root caries globally. The clinical management of root caries is challenging due to the difficulty in moisture isolation. The root caries is caused by the release of organic acids from cariogenic bacteria which results in the dissolution of cementum and dentin of the root. The purpose of this study is to study the efficacy of modified saturated calcium phosphate solution (CaP) supplement with zinc (Zn(2+)) and/or fluoride (F(-)) in providing root cementum surfaces less susceptible to acid dissolution and bacterial colonization. METHODS: Human root cementum sections from extracted premolars were treated with three modified calcium phosphate solutions (M/A-CaPs) respectively: (A) CaP-F/Zn, supplemented with F(-) and Zn(2+); (B) CaP-F, supplemented with F(-) only; (C) CaP-Zn, supplemented with Zn(2+) only. The surface characteristics of treated cementum sections were investigated using scanning electron microscopy (SEM) and fourier transform infrared spectroscopy (FT-IR). Following the acid attack and Streptococcus mutans challenge, M/A-CaPs treated cementum surfaces were analysed using inductive coupled plasma (ICP) and SEM respectively. RESULTS: Compared with the control group, M/A-CaPs treated cementum presented significant improvements in resistance to acid dissolution and bacterial colonization. Among M/A-CaPs, the CaP-F/Zn treated cementum surfaces released the lowest amount of Ca(2+) ions (2.11 ± 0.51 ppm) upon acid challenge (n = 3, p < 0.01) and also presented the most significant inhibiting effect against the colonization of S. mutans (n = 180, p < 0.05). CONCLUSIONS: Saturated calcium phosphate solution CaP supplemented with both F(-) and Zn(2+) could be applied as an effective coating material providing acid resistance and antibacterial property on cementum surfaces. The modified calcium phosphate-based solution could be a new treatment strategy to prevent the development of root caries and arrest the further progression of root caries.

Experimental antibacterial and mineralizing calcium phosphate-based treatment for dentin surfaces.

OBJECTIVES: This study aimed to determine the efficacy of experimental calcium phosphate-based solutions (sCaP) containing fluoride (F), with and without zinc (Zn) ions on reducing susceptibility to acid dissolution and Streptococcus mutans (S. mutans) colonization of dentin surfaces. METHODS: Dentin sections were treated with double distilled water (control) and with sCaP solutions differing in pH and in F(-) and/or Zn(2+) ion concentrations. Solutions A (pH 7); B, C, and D (pH 5.5); solution C, twice Zn(2+) and F(-) ion concentration compared to B; solution D is similar to C but without Zn(2+). The dentin surfaces were characterized using scanning electron microscopy (SEM), x-ray diffraction, and Fourier Transform Infrared spectroscopy. Dissolution was determined in acidic buffer. Bacterial (S. mutans) attachment and growth were evaluated using SEM and Bioquant. Statistical analyses applied analysis of variance (ANOVA) and Duncan's multiple Range test. RESULTS: Compared to control, dentin surfaces treated with sCaP solutions showed: (a) occluded dentin tubules; (b)reduced susceptibility to acid dissolution; and (c) Zn(2+) ions were more effective than F(-) ions in inhibiting bacterial colonization. SIGNIFICANCE: Acidic sCaP containing both F and Zn ions have mineralizing, acid resistance, and antibacterial effects and may be potentially useful as a strategy against dentin caries formation and progression.

Preparation and characterization of fluorinated porcine hydroxyapatite.

Simple chemical and thermal treatments were applied to prepare fluorinated porcine hydroxyapatite (FPHA). Morphology of FPHA was observed using SEM. Physiochemical characteristics, namely crystalline phase, chemical composition, functional groups, and binding energy of fluorine were investigated using XRD, EDX, FTIR, and XPS respectively. Concentration of free fluoride ion released from FPHA in HCl solution (pH 3.0-4.0) was detected using a fluoride ion concentration meter. SEM, XPS, XRD, and FTIR results confirmed the fluorination of porcine hydroxyapatite (PHA). Significant crystal morphological difference was observed between PHA and FPHA. Concentration of free fluoride ion released from FPHA increased with rising concentration of immersion solution and length of immersion period. Fluoride was successfully incorporated into PHA by chemical and thermal processes in this study. Fluoride incorporation rate into PHA was a strong function of the fluorine concentration in the immersion solution.

Wnt/ß-catenin signaling participates in cementoblast/osteoblast differentiation of dental follicle cells.

Dental follicle cells (DFCs) are reported to contain stem cells. The canonical Wnt signaling pathway plays an important role in stem cell self-renewal and tooth development through ß-catenin expression. The objective of this study was to investigate whether Wnt/ß-catenin signaling pathway participates in the cementoblast/osteoblast differentiation of rat DFCs. Immunohistochemistry was used to compare the expression of ß-catenin in rat mandibular first molars from postnatal days 1-13. The effects of Wnt/ß-catenin signaling on DFCs in vitro were examined by lithium chloride (LiCl) treatment by immunofluorescence, cell counting, dual-luciferase reporter assays, western blotting, and alkaline phosphatase activity analysis. ß-Catenin expression was absent in the dental follicles on days 1 and 3 in vivo. It then progressively increased from days 5 to 13. In vitro studies of the DFCs showed that LiCl stimulation caused ß-catenin, which was mainly located in the cell membrane and cytoplasm of DFCs, to be immediately transferred to the nucleus and led to the inhibition of proliferation at 12 and 24 hr. LiCl treatment also downregulated the levels of phosphorylated-ß-catenin, while upregulating the levels of total ß-catenin, nuclear ß-catenin, osteocalcin, runt-related transcription factor 2, and collagen type I. In addition, LiCl enhanced the ß-catenin/T-cell factor luciferase activity and alkaline phosphatase activity. These results suggest that Wnt/ß-catenin signaling pathway positively regulates the cementoblast/osteoblast differentiation of the DFCs.

Effect of ZnCl2 on plaque growth and biofilm vitality.

OBJECTIVE: The aim of this study was to evaluate the effects of ZnCl(2) on plaque-growth and vitality pattern of dental biofilm and to determine the optimum zinc concentration for the inhibition of plaque formation. DESIGN: Data were collected from nine volunteers for whom a special-designed acrylic appliance was prescribed after a careful dental check up. The volunteers rinsed twice daily for 2min with ZnCl(2) of 2.5, 5, 10, 20mM as treatment and double distilled water (DDW) as control in respective assigned test weeks. The plaque index (PI) was assessed after 48h of appliance wearing. The glass discs with the adhered biofilm were removed from the splints and stained with two fluorescent dyes. The biofilm thickness (BT) and bacterial vitality of the whole biofilm as well as the mean bacterial vitality (BV) of the inner, middle and outer layers of biofilm were evaluated under confocal laser scanning microscope (CLSM). RESULTS: PI, BT and BV of biofilms treated by various concentrations of ZnCl(2) were reduced significantly when compared with the DDW group (p<0.05). PI, BT and BV of the 2.5mM ZnCl(2) group was significantly higher than groups of 5, 10, 20mM ZnCl(2) (p<0.05). The mean BV of the 3 layers (inner, middle and outer layers) showed that 2.5mM ZnCl(2) was the lowest concentration to inhibit BV in the outer layer, 5mM was the lowest concentration to extend this inhibition of BV to the middle layer, and none of the concentrations investigated in this study has shown any effect on bacteria inhibition in the inner layer. CONCLUSION: Zinc ions exhibited possible inhibitory effects on plaque formation, and have a promising potential to be used as an antibacterial agent in future dentifrices and mouthrinses.

Calcium phosphate-based solutions promote dentin tubule occlusions less susceptible to acid dissolution.

PURPOSE: To determine the efficacy supersaturated calcium phosphate (CaP) solutions containing fluoride (F) and zinc (Zn) ions in occluding dentin tubules with precipitates less susceptible to acid dissolution and to compare the performance of these solutions with the oxalate solutions containing calcium (Ca) or phosphate (P) ions. METHODS: Dentin sections from human molars divided into groups: Group A - control (treated with double distilled H2O), Groups A1, A2 and A3 were treated with experimental solutions supersaturated with respect to F and Zn-substituted calcium phosphates. Solutions A1 and A2 were similar in composition but differed in pH values (A1, pH 7; A2, pH 5.5). Solutions A2 and A3 were similar in pH (pH 5.5) but the A3 solution had twice the concentrations of F and Zn2+ ions compared to A2. Another group of dentin sections were treated with A3 solution, oxalate solution containing Ca (OX/Ca) and OX solution containing P (OX/P). The control and treated dentin sections were characterized using scanning electron microscopy. RESULTS: All treated dentin sections showed occluded dentin tubules; with the group A3 showing the highest percent of occluded dentin tubules. The precipitates in the dentin tubules treated with A3 remained while those treated with OX/Ca or OX/P dissolved after exposure to an acidic buffer.

[Expression and biological roles of heat shock protein 25 in rat dental follicle cells].

OBJECTIVE: To examine the expression of heat shock protein 25 (HSP-25) in dental rat follicles in vivo and in vitro in order to investigate the possible effect of HSP-25 on cell proliferation and alkaline phosphatase (ALP) activity. METHODS: The expression of HSP-25 in mandibles of postnatal rats from day 1, 3, 5, 7, 9, 11 was examined by immunohistochemistry in vitro, the expression of HSP-25 in the dental follicle cells was detected by the indirect immunofluorescence method. Methyl thiazolyl tetrazolium (MTT) assay, flowcytometry and ALP assay were used to detect the effect of HSP-25 on rat dental follicles. RESULTS: HSP-25 expression was absent or weak in rat dental follicle cells at early postnatal stage and present from day 5 till day 11. HSP-25 was detected in the cytoplasm of cultured dental follicle cells. MTT results showed no effect could be detected on dental follicle cell proliferation after stimulation of different concentrations of HSP-25 on day 1, 2, 3. Flowcytometry results also exhibited no difference in cell cycles after stimulation of HSP-25 at 0 microg/L and 100 microg/L. HSP-25 at a concentration of 50 microg/L and 100 microg/L could up-regulate the ALP activity on day 9. CONCLUSIONS: Expression of HSP-25 increases chronologically in the rat dental follicle cells. HSP-25 locates in the cytoplasm of cultured rat dental follicle cells. HSP-25 has no effect on the proliferation of dental follicle cells, however it can up-regulate the ALP activity.

[Clinical evaluation of periapical endodontic surgery for endodontic failure].

OBJECTIVE: To evaluate the clinical outcome of periapical endodontic surgery for teeth that can't be treated by nonsurgical endodontic methods. METHODS: Sixty-two affected teeth were chosen for surgical endodontic treatment, of which 31 teeth underwent periapical curettage and the others were treated by root-end resection, retrograde preparation and filling. A radiography was taken immediately after surgery and was compared with those taken at 12 and 24 months. The results of two groups were analyzed using the chi2 test. RESULTS: The success rate for retrograde filling was higher (85% after 12 months, 88% after 24 months) compared with that of periapical curettage (52% after 12 months, 45% after 24 months). The difference in success rate between the two groups was statistically significant. CONCLUSIONS: Ultrasonic root-end preparation and retrograde filling is a good choice of treatment when the teeth can't be treated appropriately by nonsurgical treatment.

HSP25 affects the proliferation and differentiation of rat dental follicle cells.

AIM: To detect the expression of HSP25 in rat dental follicles both in vivo and vitro, and explore the underlying mechanism of HSP25 on the proliferation and differentiation of rat dental follicle cells (DFCs). METHODOLOGY: Immunohistochemistry was performed to detect the expression of HSP25 in mandibles of postnatal rats on days 1, 3, 5, 7, 9 and 11 in vivo. In vitro, the expression of HSP25 in DFCs was detected by an indirect immunofluorescence assay. Thiazolyl blue tetrazolium bromide (MTT) assay, flow cytometry and alkaline phosphatase (ALP) assay were used to identify the time-course effect mediated by different concentrations of recombinant murine HSP25 of 0, 1, 10, 50 and 100 ng/mL on rat DFCs. RESULTS: Expression of HSP25 was not detected in dental follicles of the rats until day 5 after birth, but became up-regulated in a time-dependent manner till day 11. HSP25 was detected in the cytoplasm of cultured rat DFCs. No significant difference could be observed in the proliferation of DFCs after stimulation with different concentrations of HSP25 on days 1, 2 and 3 (P > 0.05). HSP25 at concentrations of 50 ng/mL and 100 ng/mL up-regulated the ALP activity of DFCs on day 9 (P < 0.05). CONCLUSION: HSP25-immunoreactivity increased chronologically during the development of dental follicles. The protein had no significant effect on cell proliferation but may play a role in cementoblast/osteoblast differentiation of DFCs.

[Evaluation of sealing ability of three kinds endodontic materials as root canal sealers].

OBJECTIVE: To compare the apical microleakage of Vitapex (calcium hydroxide based paste) with that of AH-plus and zinc oxide eugenol sealer when used with laterally condensed gutta percha obturation technique. METHODS: One hundred single rooted human anterior teeth were instrumented and randomly divided into three experimental groups (A, B, C) of 30 teeth each and two control groups (D, E) of 5 teeth each. Group A was filled with laterally condensed gutta-percha using Vitapex as sealer. Group B was filled with laterally condensed gutta-percha using AH-plus as sealer. Group C was filled with laterally condensed gutta-percha using zinc oxide eugenol as sealer. Group D was the positive control. Group E was the negative control, which were coated with nail polish to entire root surface. Teeth were then suspended in 2% methylene blue. After this, teeth were demineralized dehydrated and cleared. Linear dye penetration was determined under stereomicroscope with calibrated eye piece. RESULTS: The mean dye penetration for group A, B, C were respectively (0.57 +/- 0.56) mm, (0.79 +/- 0.96) mm and (1.07 +/- 1.12) mm. Group D demonstrated maximum dye penetration. Group E showed no dye penetration. There was no statistically significant difference between group B and group C (P > 0.05). However, there was statistically significant difference between group A and group B, C (P < 0.01). CONCLUSION: This study showed that Vitapex used as endodontic sealer material are better than AH-plus sealer and zinc oxide eugenol sealer.

[Treatment of chronic apical periodontitis teeth complicated by open apices with Vitapex in the adults].

PURPOSE: The aim of this study was to evaluate Vitapex (a premixed calcium hydroxide and iodoform paste) for treatment of chronic apical periodontitis complicated by incompletely developed apices in the adults. METHODS: 36 teeth with incompletely formed apices were selected. After the root canals were prepared and sterilized , Vitapex was used in the apexification. All the patients were followed-up clinically and radiographically 3 months and 10-18 months postoperatively. The root canal were then filled with Obtura II gutta-percha when the apical barrier could be detected. RESULTS: A radiographic evaluation showed that 7(19.4%) teeth completed root development and apical closure. 27 (75%) teeth could be detected apical barrier. 2 (5.6%) teeth were failed. The overall success rate was 94.4%. The average period of the whole endodontic treatment was 13.0 weeks. CONCLUSION: Vitapex is a good material in the treatment of chronic apical periodontitis complicated by incompletely formed apices in the adults.

[Clinical management of open apices teeth with mineral trioxide aggregate (MTA) as apical barrier in adults].

OBJECTIVE: To evaluate the clinical effect of treatment of open apices teeth with mineral trioxide aggregate (MTA) compared with apexification using Vitapex in the adult. METHODS: The root canals of 41 anterior teeth and premolars with single canal and open apices in adults were cleaned and shaped, and then disinfected with calcium hydroxide. The apical root canals of 21 teeth in experimental group were filled with MTA to create a 3-5 mm apical barrier. The remainder of the canals was filled with AH plus and Obtura II gutta-percha. The canals of 20 teeth in control were treated with Vitapex. The root canals were then filled with Obtura II gutta-percha when the apical barrier could be detected. The visit times, period and result of the treatment were recorded for all cases. RESULTS: Good result was achieved in the most cases in the experimental group. The postoperative X-ray films showed that the canals of 15 teeth were obturated well. 6 teeth showed over-filling by 0.5-2 mm. The recalled patients declared their teeth to be asymptomatic except one. The recall radiographs indicated that the apical radiolucent areas of the teeth with pre-existing apical lesion decreased apparently or disappeared completely, except one tooth with large apical radiolucency. No new radiolucency was found around the roots. In the control group, the apexification of 11 teeth succeeded, and 9 failed. The average visit times was 3.5 in experimental group and 6.0 in control. The average period of the whole endodontic treatment was 11.8 days in experimental group and 306.8 in control. CONCLUSION: MTA is more effective and quicker than apexification in treatment of teeth with open apices in adults.