Influence of acrylamide monomer addition to the acrylic denture-base resins on mechanical and physical properties

The aim of the study was to evaluate the effect of adding acrylamide monomer （AAm） on the characterization, flexural strength, flexural modulus and thermal degradation temperature of poly（methyl methacrylate） （PMMA） denture-base resins. Specimens （n= 10） were fabricated from a conventional heat-activated QC-20 （Qc-） and a microwave heat-activated Acron MC （Ac-） PMMA resins. Powder/ liquid ratio followed the manufacturer＇s instructions for the control groups （Qc-c and Ac-c） and for the copolymer groups, the resins were prepared with 5% （-5）, 10% （- 10）, 15% （- 15） and 20% （-20） acrylamide contents, according to the molecular weight ratio, respectively. The flexural strength and flexural modulus were measured by a three-point bending test. The data obtained were statistically analyzed by Kruskal-Wallis test （a=O.05） to determine significant differences between the groups, The chemical structures of the resins were characterized by the nuclear magnetic resonance spectroscopy. Thermal stabilities were determined by thermogravimetric analysis （TGA） with a heating rate of 10 ~C.min-1 from 35 ~C to 600 ~C. Control groups from both acrylic resins showed the lowest flexural strength values. Qc-15 showed significant increase in the flexural strength when compared to Qc-c （P〈O.01）. Ac-10 and Ac-15 showed significance when compared to Ac-c （P〈O.01）. Acrylamide incorporation increased the elastic modulus in Qc-10, Qc-15 and Qc-20 when compared to Qc-c （P〈0.01）. Also significant increase was observed in Ac-10, Ac-15 and Ac-20 copolymer groups when compared to Ac-c （P〈0.01）. According to the 1H-nuclear magnetic resonance （NMR） results, acrylamide copolymerization was confirmed in the experimental groups. TGA results showed that the thermal stability of PMMA is increased by the insertion of AAm.     

Experimental Measurement of Utricle System Dynamic Response to Inertial Stimulus

The membranous utricle sac of the red-eared turtle was mounted in a piezoelectric actuated platform mounted on the stage of a light microscope. The piezoelectric actuator oscillated the base of the neuroepithelium along a linear axis. Displacements were in the plane of the utricle and consisted of a linear sinusoidal-sweep signal starting at 0 and increasing to 500 Hz over 5 s. This inertial stimulus caused measurable shear displacement of the otoconial layer’s dorsal surface, resulting in shear deformation of the gelatinous and column filament layers. Displacements of the otoconial layer and a reference point on the neuroepithelium were filmed at 2,000 frames/s with a high-speed video camera during oscillations. Image registration was performed on the video to track displacements with a resolution better than 15 nm. The displacement waveforms were then matched to a linear second-order model of the dynamic system. The model match identified two system mechanical parameters—the natural circular frequency ω_n and the damping ratio ζ—that characterized the utricle dynamic response. The median values found for the medial-lateral axis on 20 utricles with 95 % confidence intervals in parenthesis were as follows: ω_n = 374 (353, 396) Hz and ζ = 0.50 (0.47, 0.53). The anterior-posterior axis values were not significantly different: ω_n = 409 (390, 430) Hz and ζ = 0.53 (0.48, 0.57). The results have two relevant and significant dynamic system findings: (1) a higher than expected natural frequency and (2) significant under damping. Previous to this study, utricular systems were treated as overdamped and with natural frequencies much lower that measured here. Both of these system performance findings result in excellent utricle time response to acceleration stimuli and a broad frequency bandwidth up to 100 Hz. This study is the first to establish the upper end of this mechanical system frequency response of the utricle in any animal.     

In vitro analysis of riboflavin-modified,experimental, two-step etch-and-rinse dentin adhesive:Fourier transform infrared spectroscopy and micro-Raman studies

To modify two-step experimental etch-and-rinse dentin adhesive with different concentrations of riboflavin and to study its effect on the bond strength,degree of conversion,along with resin infiltration within the demineralized dentin substrate,an experimental adhesive-system was modified with different concentrations of riboflavin(mlm,0,1%,3%,5%and 10%).Dentin surfaces were etched with 37%phosphoric acid,bonded with respective adhesives,restored with restorative composite-resin,and sectioned into resin-dentin slabs and beams to be stored for 24 h or 9 months in artificial saliva.Micro-tensile bond testing was performed with scanning electron microscopy to analyse the failure of debonded beams.The degree of conversion was evaluated with Fourier transform infrared spectroscopy(FTIR) at different time points along with micro-Raman spectroscopy analysis.Data was analyzed with one-way and two-way analysis of variance followed by Tukey’s for pair-wise comparison.Modification with 1%and 3%riboflavin increased the micro-tensile bond strength compared to the control at 24 h and 9-month storage with no significant differences in degree of conversion(P<0.05).The most predominant failure mode was the mixed fracture among all specimens except 10%riboflavin-modified adhesive specimens where cohesive failure was predominant.Raman analysis revealed that 1%and 3%riboflavin adhesives specimens showed relatively higher resin infiltration.The incorporation of riboflavin in the experimental two-step etch-and-rinse adhesive at 3%(mlm) improved the immediate bond strengths and bond durability after 9-month storage in artificial saliva without adversely affecting the degree of conversion of the adhesive monomers and resin infiltration.     

Porous titanium granules in critical size defects of rabbit tibia with or without membranes

Recently, porous titanium granules （PTGs） have been indicated for the preservation of the dimensions of post-extraction sockets, as a filler in sinus lift procedures and for the treatment of peri-implant and periodontal defects, based on the osteoconductivity and dimensional stability of the titanium granules. However, there is a lack of information regarding the use of this material in larger defects and in conjunction with membranes. The objective of this study is to test the behavior of PTGs used to fill critical size defects in rabbit tibiae, with and without membranes. Critical defects were created in both tibiae of rabbits, divided randomly into three groups： Group A （defect filled with PTG）, Group B （defect filled with PTG＋collagen membrane） and a control group （empty defect）. After six weeks, histomorphometric analysis was performed. The results showed more defect closures at the cortical area （87.37%±2.2%） and more bone formation at the marrow area （57.6%± 1.3%） in Group B, in comparison with the other groups （P〈0.05）; the use of membranes improved the material stability expressed as more percentages of the original material when membranes were used （P〈0.05）. Finally, inflammatory reactions were observed when the granules were not protected by membranes. In spite of the limitations of this animal study, it may be concluded that PTG particles are osteoconductive and allow bone growth. The PTG particles must be covered by a membrane, especially when grafting larger defects, in order to control particle migration, promote clot stabilization and separate the PTG graft from undesired soft tissue cells.     

Effect of colouring green stage zirconia on the adhesion of veneering ceramics with different thermal expansion coefficients

This study evaluated the adhesion of zirconia core ceramics with their corresponding veneering ceramics, having different thermal expansion coefficients （TECs）, when zirconia ceramics were coloured at green stage. Zirconia blocks （N=240; 6 mm x 7 mm x 7 mm） were manufactured from two materials namely, ICE Zirconia （Group 1） and Prettau Zirconia （Group 2）. In their green stage, they were randomly divided into two groups. Half of the specimens were coloured with colouring liquid （shade A2）, Three different veneering ceramics with different TEC （ICE Ceramic, GC Initial Zr and IPS e.max Ceram） were fired on both coloured and non-coloured zirconia cores. Specimens of high noble alloys （Esteticor Plus） veneered with ceramic （VM 13） （n= 16） acted as the control group. Core-veneer interface of the specimens were subjected to shear force in the Universal Testing Machine （0.5 mm-min-1）. Neither the zirconia core material （P=0.318） nor colouring （P=0.188） significantly affected the results （three-way analysis of variance, Tukey＇s test）. But the results were significantly affected by the veneering ceramic （P=0.000）. Control group exhibited significantly higher mean bond strength values （45.7__.8） MPa than all other tested groups （（27.1__.4.1）-（39.7__.4.7） and （27.4__.5.6）-（35.9___4.7） MPa with and without colouring, respectively） （P~0.001）. While in zirconia-veneer test groups, predominantly mixed type of failures were observed with the veneering ceramic covering ~ 1/3 of the substrate surface, in the metal-ceramic group, veneering ceramic was left adhered 1/3 of the metal surface. Colouring zirconia did not impair adhesion of veneering ceramic, but veneering ceramic had a significant influence on the core-veneer adhesion. Metal-ceramic adhesion was more reliable than all zirconia-veneer ceramics tested.     

Antimicrobial activity of alexidine alone and associated with N-acetylcysteine against Enterococcus faecalis biofilm

The purpose of this study was to assess the efficacy of alexidine（ALX）,alone and combined with N-acetylcysteine（NAC）,in eradicating two Enterococcus faecalis strain biofilms.The biofilms of E.faecalis ATCC 29212 and the clinical isolate E.faecalis D1 were grown in the MBEC-high-throughput device for 24 h and were exposed to five twofold dilutions of ALX（2%–0.007 8%）alone and combined with100 mg？mL21NAC,for 1 and 5 min.Eradication was defined as 100%kill of biofilm bacteria.The Student’s t-test was used to compare the efficacy of the associations of the two irrigants.After 1-min contact time,ALX eradicated the biofilms at all concentrations except for 0.007 8%and 0.015 6%–0.007 8%with E.faecalis ATCC 29212 and E.faecalis D1,respectively.Similar results for eradication and concentration were obtained when it was combined with 100 mg？mL21NAC.After 5 min of contact time,ALX alone and combined with NAC eradicated all enterococci biofilms.ALX showed antimicrobial properties against the two E.faecalis strain biofilms tested at very low concentrations,and its combined use with NAC was not seen to enhance its activity.     

A matched cohort comparison of mTHPC-mediated photodynamic therapy and trans-oral surgery of early stage oral cavity squamous cell cancer

Photodynamic therapy (PDT) of early stage oral cavity tumors have been thoroughly reported. However, statistical comparison of PDT to the surgical treatment is not available in published literature. We have identified and matched cohorts of patients with early stage oral cavity cancers undergoing surgery (n = 43) and PDT (n = 55) from a single institute experience. The groups are matched demographically and had the same pre-treatment screening and follow-up schedule. Both groups consisted only of tumors thinner than 5 mm to ensure comparability. The endpoints were local disease free survival, disease free survival, overall survival and response to initial treatment. Local disease free survival at 5 years were 67 and 74 % for PDT and surgery groups, respectively [univariate HR = 1.9 (p = 0.26), multivariable HR = 2.7 (p = 0.13)]. Disease free survival at 5 years are 47 and 53 % for PDT and surgery groups, respectively [univariate HR = 0.8 (p = 0.52), multivariable HR = 0.75 (p = 0.45)]. Overall survival was 83 and 75 % for PDT and surgery groups, respectively [(univariate HR = 0.5 (p = 0.19), multivariable HR = 0.5 (p = 0.17)]. In the PDT group, six patients (11 %) and in the surgery group 11 patients (26 %) had to receive additional treatments after the initial. All of the tested parameters did not have statistical significant difference. Although there is probably a selection bias due to the non-randomized design, this study shows that PDT of early stage oral cavity cancer is comparable in terms of disease control and survival to trans-oral resection and can be offered as an alternative to surgical treatment.     

A novel protein-repellent dental composite containing 2-methacryloyloxyethyl phosphorylcholine

Secondary caries due to biofilm acids is a primary cause of dental composite restoration failure.To date,there have been no reports of dental composites that can repel protein adsorption and inhibit bacteria attachment.The objectives of this study were to develop a protein-repellent dental composite by incorporating 2-methacryloyloxyethyl phosphorylcholine(MPC) and to investigate for the first time the effects of MPC mass fraction on protein adsorption,bacteria attachment,biofilm growth,and mechanical properties.Composites were synthesized with 0(control),0.75%,1.5%,2.25%,3%,4.5%and 6%of MPC by mass.A commercial composite was also tested as a control.Mechanical properties were measured in three-point flexure.Protein adsorption onto the composite was determined by the microbicinchoninic acid method.A human saliva microcosm biofilm model was used.Early attachment at 4 h,biofilm at 2 days,live/dead staining and colony-forming units(CFUs) of biofilms grown on the composites were investigated.Composites with MPC of up to 3%had mechanical properties similar to those without MPC and those of the commercial control,whereas 4.5%and 6%MPC decreased the mechanical properties(P<0.05).Increasing MPC from 0 to 3%reduced the protein adsorption on composites(P<0.05).The composite with 3%MPC had protein adsorption that was 1/12 that of the control(P<0.05).Oral bacteria early attachment and biofilm growth were also greatly reduced on the composite with 3%MPC,compared to the control(P<0.05).In conclusion,incorporation of MPC into composites at 3%greatly reduced protein adsorption,bacteria attachment and biofilm CFUs,without compromising mechanical properties.Protein-repellent composites could help to repel bacteria attachment and plaque build-up to reduce secondary caries.The protein-repellent method might be applicable to other dental materials.     

Tolerability and effects on quality of life of liposomal nasal spray treatment compared to nasal ointment containing dexpanthenol or isotonic NaCl spray in patients with rhinitis sicca

This study aimed to investigate symptom reduction via the liposomal nasal spray LipoNasal (LN) in patients with rhinitis sicca. Tolerability and the impact on quality of life were also examined. The same parameters were established in parallel for treatment approaches with Bepanthen (BP) nasal ointment containing dexpanthenol and the Rhinomer (RH) nasal spray containing NaCl. This prospective, controlled, open-label observation study was a multicenter trial. 92 patients with rhinitis sicca were allocated to three arms according to their symptoms: LN: n = 33; BP: n = 32 and RH: n = 27. The study comprised three visits at an interval of 14 days. Efficacy was examined by the Rhinitis Sicca Symptom Score (RSSS) documented daily and at the visits based on an endoscopic evaluation. The nasal spray sensory scale was used to investigate the tolerability. Quality of life (QoL) was measured by means of the Rhinoconjunctivitis Quality of Life Questionnaire (RQLQ) and the “Short Form 12” of the “Impact on Health-Related Quality of Life (HRQL)” questionnaire on general quality of life. Nasal symptoms improved significantly (p = 0.001) under all three treatment approaches, reflected by the reduction in the RSSS and the Endoscopy Sum Score. A comparison of the three groups showed that no therapy was significantly superior to any of the others (p = 0.410). The tolerability of all treatments was good. Concerning the nasal moisturization, LipoNasal was evaluated better than Bepanthen and Rhinomer. Quality of life improved in all groups, but not significantly. The results show good efficacy and tolerability of the liposomal nasal spray compared to generally recognized treatments of rhinitis sicca with dexpanthenol nasal ointment and NaCl nasal spray. LipoNasal therefore constitutes a good treatment for patients suffering from dry nose.     

Successful Treatment of Postpeak Stage Patients with Class Ⅱ Division 1 Malocclusion Using Non-extraction and Multiloop Edgewise Archwire Therapy： A Report on 16 Cases

Aim To determine cephalometrically the mechanism of the treatment effects of non-extraction and multiloop edgewise archwire （MEAW） technique on postpeak Class Ⅱ Division 1 patients.
Methodology In this retrospective study, 16 postpeak Class Ⅱ Division 1 patients successfully corrected using a non-extraction and MEAW technique were cephalometrically evaluated and compared with 16 matched control subjects treated using an extraction technique. Using CorelDRAW software, standardized digital cephalograms preand post-active treatments were traced and a reference grid was set up. The superimpositions were based on the cranial base, the mandibular and the maxilla regions,and skeletal and dental changes were measured. Changes following treatment were evaluated using the paired-sample t-test. Student＇s t-test for unpaired samples was used to assess the differences in changes between the MEAW and the extraction control groups.
Results The correction of the molar relationships comprised 54% skeletal change （mainly the advancement of the mandible） and 46% dental change. Correction of the anterior teeth relationships comprised 30% skeletal change and 70% dental change.
Conclusion The MEAW technique can produce the desired vertical and sagittal movement of the tooth segment and then effectively stimulate mandibular advancement by utilizing the residual growth potential of the condyle.     

Diagnostic yield of a one-stop neck lump clinic

Diagnostic clinics for patients with neck lumps were established across the UK in response to NICE guidance on cancer services. The guidance stated that a surgeon and a cytopathologist among its other key recommendations should staff each clinic. The aim of this study was to establish the diagnostic yield of this clinic at Wolverhampton. A prospective cohort study was conducted of patients attending a one-stop neck lump clinic over a period of 30 months. Patients’ characteristics, diagnostic tests and outcomes were recorded and the data analysed. Of 333 patients, n = 65 (20 %) had no lump, n = 214 (64 %) had a benign lump and n = 54 (16 %) had a malignant lump. Older age of patients and a history of smoking were found to be significantly higher when a malignant lump was diagnosed when compared with a benign lump. In the benign lump group, freehand FNAC had an accuracy of 87 % (n = 48/55), while USS-guided FNAC had an accuracy of 74 % (n = 32/43). Diagnosis was confirmed on the same day for the majority of patients (n = 178, 84 %). In the malignant lump group, freehand FNAC had an accuracy of 82 % (n = 28/34), while USS-guided FNAC had an accuracy of 81 % (n = 17/21). Diagnosis on the same day was confirmed for 74 % of the patients (n = 40). The clinic in our unit achieved an overall diagnostic yield of 84 %. Outcomes regarding age, sex, smoking, size and site of neck lumps and accuracy of FNAC were in line with published data. The study showed that this one-stop neck lump clinic was better at excluding malignancy than diagnosing it.     

Bisphosphonatassoziierte Osteonekrose des Kiefers

ZusammenfassungHintergrund Im Jahr 2003 wurde erstmals über den Zusammenhang zwischen Bisphosphonaten (BP) und Osteonekrosen der Kiefer (ONJ) berichtet. Seitdem gab es zahlreiche Meldungen, die dieses neue Krankheitsbild als therapeutisch schwer beeinflussbare Erkrankung beschreiben. Wegen ihrer hemmenden Wirkung auf die osteoklastäre Knochenresorption werden BP in zunehmender Zahl bei Patienten mit skeletalen Komplikationen maligner Erkrankungen und Osteoporose eingesetzt. Wir präsentieren einen Literaturüberblick, die Ergebnisse einer Befragung unter Kliniken für Mund-, Kiefer- und Gesichtschirurgie und unsere eigenen Patienten.Material und Methoden Es wurden 349 Fälle aus der Literatur, 54 Falldokumentationen von Kliniken für Mund-, Kiefer- und Gesichtschirurgie und 19 eigene Fälle nach BP- und Komedikation, Grund- und Begleiterkrankung, Lokalisation, Histologie sowie Therapie analysiert (n=73).Ergebnisse Von den 73 untersuchten Patienten erhielten 68 (93%) Pamidronat und/oder Zoledronat. 69 Patienten (94%) wurden BP wegen einer malignen Grunderkrankung, 3 (5%) wegen Osteoporose und 1 Patient (1%) wegen eines Mb Paget verabreicht. Die ONJ traten bei 54 Patienten (74%) im Unterkiefer, bei 12 (16%) im Oberkiefer und 4 (5%) in beiden Kiefern auf. Bei 38 Patienten (52%) waren Zahnextraktionen vorausgegangen, bei 35 (48%) entwickelte sich die ONJ spontan. Histologisch fanden sich chronisch-fibrosierende und floride, eitrige Osteomyelitiden, auffällig häufig auch Actinomyceskolonien im Knochen. 9 Patienten (12%) wurden rein konservativ behandelt, 52 (71%) unterzogen sich teils mehrfach begrenzten chirurgischen Maßnahmen (z. B. Dekortikation) und bei 19 Patienten (26%) erfolgten Kieferteilresektionen. Insgesamt konnte nur bei 55% der Patienten eine Heilung der ONJ erzielt werden. Die höchste Erfolgsrate (88%) wurde bei den Patienten mit Resektionen beobachtet.Diskussion Im Verhältnis zur millionenfachen Anwendung der BP treten ONJ nur selten auf, bei Tumorpatienten kommt es unter Pamidronat und Zoledronat bei 4–10% zur ONJ. Wegen der Ähnlichkeit mit der Phosphornekrose (phossy jaw) nennen einige Autoren die Erkrankung bis-phossy jaw. Anhand der vorliegenden Daten kann aber eine Kausalität zwischen BP und ONJ nur vermutet werden; wir empfehlen die Bezeichnung bisphosphonatassoziierte Osteonekrose. Die Therapie der Wahl ist die chirurgische Nekroseentfernung und sichere plastische Deckung. Eine kontinuierliche und systematische Prophylaxe ist notwendig. Die Zusammenarbeit von Onkologen, Zahnärzten und Mund-, Kiefer- und Gesichtschirurgen muss ein zentraler Aspekt sein.     

Role of MR imaging in laryngoscleroma

To evaluate the role of MR imaging in patients with laryngoscleroma. We retrospectively reviewed the MR imaging of 14 patients (11 female, 3 male with mean age of 31 years) with pathologically proven laryngoscleroma. They presented with dysphonia (n = 12), stridor (n = 8) and airway obstruction (n = 4). They underwent T1- and T2-weighted MR images and post contrast study after injection of 0.1 mmol Gd/DTPA. Laryngoscleroma was seen in the subglottic (n = 13) and supraglottic (n = 1) regions. Laryngoscleroma at granulomatous stage (n = 6) appeared as diffuse circumferential soft tissue mass with high (n = 4) or mixed (n = 2) signal intensity on T2-weighted images with homogenous (n = 4) and inhomogeneous (n = 2) pattern of contrast enhancement. At fibrotic stage (n = 8), laryngoscleroma was seen as diffuse asymmetrical circumferential thickening of the subglottic region with low signal intensity on T2-weighted images and mild contrast enhancement. Subglottic lesions encircled the subglottic region with marked (n = 5) and mild (n = 9) narrowing of the airway with variable degree of extension into the trachea in three patients. There was diffuse thickening of the epiglottis, aryepiglottic folds in one patient with supraglottic scleroma. MR imaging is a non-invasive imaging modality for accurate localization, extension and staging of laryngoscleroma. These data is important for treatment planning.     

Control of vertigo in Ménière's disease by intratympanic dexamethasone

ObjectiveThe main objective was to assess the efficacy of intratympanic dexamethasone injection in controlling vertigo in unilateral Ménière's disease refractory to medical treatment.Materials and methodsA retrospective study included 25 patients with disabling unilateral Ménière's disease, defined according to the American Academy of Otorhinolaryngology-Head and Neck Surgery (AAO-HNS) criteria. Patients received intratympanic dexamethasone during the monitoring period. Control of vertigo was classified according to AAO-HNS vertigo control index, at 6 months, 1 year, and 2 years after treatment initiation. Complications and progression of hearing were also assessed.ResultsSatisfactory control (class A or B) was obtained in 92% of patients (n = 23/25) at 6 months, 68% (n = 17/25) at 1 year, and 70% (n = 16/23) at 2 years. There was no worsening of hearing in those patients who were well-controlled by this therapeutic strategy. No local or systemic complications were observed during follow-up.ConclusionDexamethasone is part of the management strategy for patients with Ménière's disease refractory to conventional treatment, implemented before destructive treatment. It achieves control of vertigo in 70% of patients at 2 years.     

Bacterial entombment by intratubular mineralization following orthograde mineral trioxide aggregate obturation:a scanning electron microscopy study

The time domain entombment of bacteria by intratubular mineralization following orthograde canal obturation with mineral trioxide aggregate（MTA） was studied by scanning electron microscopy（SEM）. Single-rooted human premolars（n560） were instrumented to an apical size #50/0.06 using ProF ile and treated as follows： Group 1（n510） was filled with phosphate buffered saline（PBS）; Group 2（n510） was incubated with Enterococcus faecalis for 3 weeks, and then filled with PBS; Group 3（n520） was obturated orthograde with a paste of OrthoM TA（BioM TA, Seoul, Korea） and PBS; and Group 4（n520） was incubated with E. faecalis for 3 weeks and then obturated with OrthoM TA–PBS paste. Following their treatments, the coronal openings were sealed with PBS-soaked cotton and intermediate restorative material（IRM）, and the roots were then stored in PBS for 1, 2, 4, 8 or 16 weeks. After each incubation period, the roots were split and their dentin/MTA interfaces examined in both longitudinal and horizontal directions by SEM. There appeared to be an increase in intratubular mineralization over time in the OrthoM TA-filled roots（Groups 3 and 4）. Furthermore, there was a gradual entombment of bacteria within the dentinal tubules in the E. faecalis inoculated MTA-filled roots（Group 4）. Therefore, the orthograde obturation of root canals with OrthoM TA mixed with PBS may create a favorable environment for bacterial entombment by intratubular mineralization.     

Isolation and characterisation of human gingival margin-derived STRO-1/MACS~+ and MACS~-cell populations

Recently,gingival margin-derived stem/progenitor cells isolated via STRO-1/magnetic activated cell sorting(MACS) showed remarkable periodontal regenerative potential in vivo.As a second-stage investigation,the present study’s aim was to perform in vitro characterisation and comparison of the stem/progenitor cell characteristics of sorted STRO-1-positive(MACS~+) and STRO-1-negative(MACS~-) cell populations from the human free gingival margin.Cells were isolated from the free gingiva using a minimally invasive technique and were magnetically sorted using anti-STRO-1 antibodies.Subsequently,the MACS~+ and MACS~- cell fractions were characterized by flow cytometry for expression of CD14,CD34,CD45,CD73,CD90,CD105,CD146/MUC18 and STRO-1.Colony-forming unit(CFU) and multilineage differentiation potential were assayed for both cell fractions.Mineralisation marker expression was examined using real-time polymerase chain reaction(PCR).MACS~+ and MACS- cell fractions showed plastic adherence.MACS~+ cells,in contrast to MACS- cells,showed all of the predefined mesenchymal stem/progenitor cell characteristics and a significantly higher number of CFUs(P<0.01).More than 95%of MACS~+ cells expressed CD105,CD90 and CD73;lacked the haematopoietic markers CD45,CD34 and CD14,and expressed STRO-1 and CD146/MUC18.MACS- cells showed a different surface marker expression profile,with almost no expression of CD14 or STRO-1,and more than 95%of these cells expressed CD73,CD90 and CD146/MUC18,as well as the haematopoietic markers CD34 and CD45 and CD105.MACS~+ cells could be differentiated along osteoblastic,adipocytic and chondroblastic lineages.In contrast,MACS- cells demonstrated slight osteogenic potential.Unstimulated MACS~+ cells showed significantly higher expression of collagen I(P<0.05) and collagen III(P<0.01),whereas MACS~- cells demonstrated higher expression of osteonectin(P<0.05;MannWhitney).The present study is the first to compare gingival MACS~+ and MACS- cell populations demonstrating that MACS~+ cells,in contrast to MACS- cells,harbour stem/progenitor cell characteristics.This study also validates the effectiveness of the STRO-l/MACS~+technique for the isolation of gingival stem/progenitor cells.Human free gingival margin-derived STRO-1/MACS~+ cells are a unique renewable source of multipotent stem/progenitor cells.     

Frequency of Alloicoccus otitidis, Streptococcus pneumoniae, Moraxella catarrhalis and Haemophilus influenzae in children with otitis media with effusion (OME) in Iranian patients

Objective

To determine the presence of common bacterial agents of otitis media with effusion (OME), together with investigation these agent in the adenoid tissue and antimicrobial susceptibility pattern of isolated bacteria in Iranian children with OME.

Methods

Polymerase chain reaction (PCR) and bacterial culture methods were used for detection and isolation of Alloicoccus otitidis, Streptococcus pneumoniae, Moraxella catarrhalis and Haemophilus influenzae in 63 middle ear fluid samples and 48 adenoid tissues from 48 OME patients. Fifteen patients were bilaterally affected. Antimicrobial susceptibility of all bacterial isolates were determined by disk agar diffusion (DAD) method.

Results

Bacteria were isolated from 47% (n = 30) of the middle ear fluid samples and 79% (n = 38) of the adenoid tissue specimens in OME patients. A. otitidis was the most common bacterial isolated from the middle ear fluid 23.8% by culture and 36.5% by PCR method. S. pneumoniae was the most prevalent pathogen (35.5% and 31.2% by culture and PCR) in the adenoid tissues. In 10 patients the same organisms were isolated from the middle ear fluid and adenoid tissue. Antimicrobial susceptibility pattern showed taht most isolates of bacteria were sensitive to ampicillin, Amoxicillin/Clavulanate and fluoroquinolones.

Conclusion

The present study, being the first report on the isolation of A. otitidis by culture method in Iran and Asian countries, shows that A. otitidis is the most frequently isolated bacterium in Iranian children having otitis media with effusion. In this study A. otitidis, S. pneumoniae, H. influenzae and M. catarrhalis are the major bacterial pathogens in patients with OME and we found that ampicillin and Amoxicillin/Clavulanate have the excellent activity against bacterial agents in Iranian children with OME.     

Enhanced Vestibulo-ocular Reflex to Electrical Vestibular Stimulation in Meniere’s Disease

Meniere’s disease is characterized by sporadic episodes of vertigo, nystagmus, fluctuating sensorineural hearing loss, tinnitus and aural pressure. Since Meniere’s disease can affect different regions of the vestibular labyrinth, we investigated if electrical vestibular stimulation (EVS) which excites the entire vestibular labyrinth may be useful to reveal patchy endorgan pathology. We recorded three-dimensional electrically evoked vestibulo-ocular reflex (eVOR) to transient EVS using bilateral, bipolar 100-ms current steps at intensities of 0.9, 2.5, 5.0, 7.5 and 10.0 mA with dual-search coils in 12 unilateral Meniere’s patients. Their results were compared to 17 normal subjects. Normal eVOR had tonic and phasic spatiotemporal properties best described by the torsional component, which was four times larger than horizontal and vertical components. At EVS onset and offset of 8.9 ms latency, there were phasic eVOR initiation (M = 1,267 °/s²) and cessation (M = −1,675 °/s²) acceleration pulses, whereas during the constant portion of the EVS, there was a maintained tonic eVOR (M = 9.1 °/s) at 10 mA. However in Meniere’s disease, whilst latency of EVS onset and offset was normal at 9.0 ms, phasic eVOR initiation (M = 1,720 °/s²) and cessation (M = −2,523 °/s²) were enlarged at 10 mA. The initiation profile was a bimodal response, whilst the cessation profile frequently did not return to baseline. The tonic eVOR (M = 20.5 °/s) exhibited a ramped enhancement of about twice normal at 10 mA. Tonic eVOR enhancement was present for EVS >0.9 mA and disproportionately enhanced the torsional, vertical and horizontal components. These eVOR abnormalities may be a diagnostic indicator of Meniere’s disease and may explain the vertigo attacks in the presence of declining mechanically evoked vestibular responses.     

Incidence of C-shaped root canal systems in mandibular second molars in the native Chinese population by analysis of clinical methods

The aims of the study were to investigate the incidence of C-shaped root canal systems in mandibular second molars in a native Chinese population using radiography and clinical examination under microscope and to compare the relative efficacies of these methods.For the recognition of C-shaped root canal system,1 146 mandibular second molars were selected and examined.Teeth with C-shaped canal systems were categorized by using the radiographic classification criteria and the modified Melton’s method.C-shaped canals were identified in 397(34.64%) mandibular second molars by radiography(type I,31.23%;type II,38.29%;type III,30.48%).Clinical examination showed that 449(39.18%) cases exhibited C-shaped canal systems(C1,22.94%;C2,48.11%;C3a,15.59%;C3b,13.36%).As for the result of the radiographic and clinical combined examination,C-shaped root canals were found in 473(41.27%) mandibular second molars(C1,21.78%;C2,45.67%;C3a,16.70%;C3b,15.86%).The incidence of C-shaped root canal diagnosed by radiographic method was statistically different from that by clinical examination and the combined examination(P,0.05).The study indicated a high incidence of C-shaped canal system in a Chinese population.The combination of microscopic and radiographic examination is an effective method in identifying the C-shaped root canal system.