Bond strength of orthodontic brackets with two adhesive systems

The aim of this study was to evaluate 1he bonds~ of or1hodontic brackets wi1h two adhesive systems TransbondTM XT Primer and Adhesive (CEP) and Transbond Plus Self Etching Primer (SEP) using two debonding technique between occlusal-gingival load (rod) and gingival-occlusal load (loop). Brackets were bonded to 92 extracted human premolar teeth that randomly divided into 2 groups. CEP and SEP of 46 specimens each. Before debonding, all teeth were stured in distilled water at room temperature for 24 hours. The specimens were debond using an INSTRON Universal Testing machine by two different me1hods ei1her rod or loop and the surfaces of substrate examined using Material Workstation Image Analyser (Leica DMLM) under 38x magnification. There was significantly di1rerence in mean bond strength when using two different me1hod of debonding ei1her loop or rod in the same grnup of adhesive system (p=0.04 and p=O.OS). There was alsn significant influence in ARI scores for both systems (p ~ 0.003). Application of 1he self-etching primer system in orthodontic treatment is beneficial for 1he clinician and patient in aspect of reducing time consuming for bonding procedure and removal of the remnant adhesive on the too1h surface after debonding or1hodontic brackets

Cytotoxicity evaluation of tricalcium phosphate on human osteoblast cell line

The aim of the study was to determine the biocompatibility of II-Tricalcium Phosphate (JI-TCP) prepared by hydrothermal and precipitation method with normal human osteoblast (NHOst) cells. For this purpose, cytotoxicity of the material was assessed using an Alamat Blue method to determine the viability ofNHOst cells grown with extracts of II-TCP in various concentrations. In addition NHOst grown on II-TCP ceramics were examined under an inverted microscope after 4, 24, 48 and 72 hours to verifY cell attachment. Staining was done using Calcein AM and Ethidium homodimers to assess viability using a Confocal Laser Scanning Microscope (CLSM). The results showed that neither hydrothermal II-TCP nor precipitation 11-TCP were cytotoxic with either of the method applied

Mechanism of bacteria adhesion on nanofilled tooth coloured restorative materials.

Accumulation of microorganisms on the tooth surfaces has always lead to dental caries. The accumulation does not limit to tooth surfaces only but also to other surfaces that exist in the oral environment, commonly dental restorative materials. The adhesions of the microbial cells to the surface texture play a major significant in the accumulation of bacteria on intraoral solid surfaces. However, information on the mechanism and the force of adhesion on different substrate specifically in nanofilled tooth coloured dental materials are scarcely available. Furthermore, there are studies reported on the role of fluoride and their uneffectiveness in combating bacteria at early periods of adhesion (Carlen et al, 2001, Montanaro et al. 2004, Mohamad et al, 2007, Auschill et al, 2002). In previous work (Moharnad et al, 2007). it was found that the biofllm thickness was higher in the glass-ionomer cement (GIG) compared to the resin composite after 8 and 24 hrs. Studies of biofilm usually evaluated by confocal laser scanning microscopy (CLSM) but limited to thickness and topography of the bacteria only, but no quantity measurement betl.veen the bacterial eel! and the substrate. Recently, Oh et al 2009 has reported effects of substrates on biofilm formation observed by atomic force microscopy (AFM) and successfully obtained the force of adhesion. Therefore, within !his study, AFM will be utilized to evaluate the force of adhesion of bacterial. In generaL the objective of this study is to investigate on the effect of polished nanofilled GIG and resin Project Leader Member composite on the bacterial accumulation. In particular, the substrate morphological variation. force of adhesion and biofilm thickness will be evaluated. Analysis of gene expressions will also be evaluated by Real-time PCR This study is importance in understanding the mechanism which potentia!fy can be used for prevention of bacterial accumulation and thus reducing the secondary caries

Synthesis of Silica Hybrid Nanoparticles and the Effect of Their Addition on the Hardness of the Dental Nanocomposites

The objective of this study is to investigate the effect of silica hybrid nanoparticles on the hardness of the dental nanocomposites. The silica hybrid nanoparticles were synthesized by sol-gel method. The powders were modified with 3-methacryloxy-propyltrimethoxy silane (γ-MPS) either by co-condensation method or one-pot method. The silanized silica were then mixed with  a mixture of bisglycidyl methacrylate (BisGMA), triethylene glycol methacrylate (TEGDMA), camphorquinone (CQ) and dimethylaminoethyl methacrylate (DMAEMA) to form dental nanocomposites.  The hardness of the nanocomposites were determined using vickers hardness. The results shown that hardness of the dental composites using silica hybrid nanoparticles synthesized via one-pot method was higher compared to the synthesized via co-condensation method. Transmission Electron Microscope (TEM), and Fourier Transform Infrared Spectroscopy (FTIR) were used for characterization

A Simple Method of Obtaining Spherical Nanosilica from Rice Husk

This paper describes the synthesis of nanosilica from rice husk. Synthesis was done by precipitation using different acids, namely, orthophosphoric acid and nitric acid which yielded nanosilica. The effect of different acids and different solvents (polar and non-polar) on the size and degree of agglomeration of the silica particles were studied. When precipitation was done without the use of solvents, the silica particles  obtained were non-spherical in shape, whereas, when precipitation was done using polar solvents (ethanol or 2-propanol), the silica particles were spherical. The use of non-polar solvents (toluene and diethyl ether) resulted in silica particles that were irregular in shape and in the case of orthophosphoric acid, a high degree of agglomeration was also noted. The degree of agglomeration was less when orthophosphoric acid was used with polar solvents as compared to nitric acid in conjunction with polar solvents. As regards the size, it ranged from approximately 70nm to 400nm when either acid was used in conjunction with polar solvents. When non-polar solvents were used, the silica particles were irregular in shape and the particle size was not estimated

Surface Roughness Evaluation Of Experimental Dental Nanocomposite After Bleaching

Bleaching or tooth whitening is getting more popular in this world that concerns esthetic [1]

Evaluation of Surface Roughness and Compressive Strength of Modified Glass Ionomer Cement with Coumarin Derivatives / Nor Ain Fatihah Azlisham...[et al.]

The objective of the present study was to evaluate the effect of incorporation of synthesized coumarin derivatives, hydrazinyl thiosemicarbazide (HZTC), an antibacterial agent on the surface roughness and compressive strength of glass ionomer cements (GICs). Two commercial GICs, Fuji II LC and Fuji VII were used in this study and act as control groups. HZTC was incorporated into GIC during its manipulation at the weight percentage of 1% and 2%. The surface roughness and compressive strength of the samples were prepared and analysed using Profilometer and universal testing machine Shimadzu AGX-Plus respectively. The data were analysed statistically to determine the significant differences among groups using Kruskal Wallis and Man Whitney test for the surface roughness, and one-way ANOVA with post-hoc Bonferonni test for the compressive strength. Statistically, the surface roughness value of Fuji II LC was significantly increased (p<0.05) at both weight percentages while the decrease value of Fuji VII was insignificant at 1% (w/w) compared to the control GICs. The compressive strength of both Fuji II LC and Fuji VII showed significantly decreased in strength values (p<0.05) at both weight percentages compared to the control GICs. Based on the results of this study, it can be concluded that the incorporation of HZTC gave measurable effects on the surface roughness and compressive strength values

Dental Implant Monitoring Using Resonance Frequency Analysis (RFA) and Cone Beam Computed Tomography (CBCT) Measurement

Dental implants commonly practiced replacing edentulous teeth. However, it is still challenging to evaluate the progress of osseointegration during the healing process after implant placement. This study aims to measure the implant stability of pre- and post-crown placement to monitor osseointegration during the healing process and correlate it with the bone quality and quantity and other parameters. Resonance Frequency Analysis (RFA) method as a standard method has been used to monitor implant stability. Ten patients from Hospital Universiti Sains Malaysia have been involved with and treated by immediate implant placement procedures on their mandibular jaw system. Monitoring was also conducted by measuring the density of bone estimated based on Cone Beam Computed Tomography data. On the basis of the study, RFA and density monitoring show that there are at least three classes of patients: Class 1 are the patients who have a significant increment of implant stability; Class 2 are the patients with constant implant stability; and Class 3 are the patients who have negative implant stability progress, or their implant stability was decreasing. On the basis of the result, monitoring of implant stability by measuring the density is still challenging, the correlation between secondary implant stability and density is not significant statistically. It is recommended in future research to evaluate the implant stability by involving more patients from different races and also correlating the implant stability with the dynamic properties such as stress distribution

Hardness of Flowable Resin Composite from Rice Husk / Nazrul M. Yusoff ...[et al.]

The aim of this study was to evaluate the hardness of two experimental dental flowable resin composites (FRCs) from rice husk in comparison to other commercial flowable resin composites. The nanohybrid silica used as the filler for the experimental FRCs was extracted from rice husk. Two commercial FRCs namely Filtek Z350 flow and Tetric N flow and the experimental FRCs with different loading of Bis-GMA at 50 % (EC50B) and 40 % (EC40B) were used. Ten cylindrical specimens (5 x 2mm) for each material were prepared in acrylic mould, light cured and polished. Prior to hardness test, all the composites were immersed in distilled water at 37 ℃ for 24 h. The Vickers’ hardness number (VHN) was measured using Vickers’ hardness tester and their surface morphology was investigated using scanning electron microscopy (SEM). The data was analyzed by one way ANOVA followed by Dunnett T3 post hoc test. Results showed that Filtek Z350 flow was statistically significantly higher in regards to VHN compared to the other FRCs tested. There was no statistically significant difference in VHN between the Tetric N flow and the two experimental FRCs. SEM showed a well distributed embedded spherical filler particle in all FRCs. In conclusion, the two experimental FRCs were comparable to Tetric N flow however Filtek Z350 flow exhibited the highest hardness. This was possibly attributed to different filler loading. Between the experimental composites, EC40B had a higher hardness which can be explained by dilution effect on monomer system. In general, mechanical properties improved with increased filler loading and dilution of base monomer