[Efficacy of four disinfectants against hepatitis B virus]

Hepatitis B is an important infection in dentistry necessitating the use of disinfectants to prevent its transmission. This study compared the efficacy of 2/100 sodium hypochlorite disinfectants manufactured by four different manufacturers namely Ashimashi, Paknaz, Vitex and Active against hepatitis B virus [HBV]. In this experimental laboratory trial, serum of 10 hepatitis B patients was poured into microtubes and Ashimashi, Paknaz, Vitex and Active disinfectants were added to them. Polymerase chain reaction [PCR] was performed with viral diagnostic kits to diagnose the virus genome. Real time PCR was performed before and after incubation with the disinfectants. The reductions occurred in the viral load of HBV were statistically analyzed by Kruskal-Wallis and Mann-Whitney U tests.No significant antiviral efficacy was noted following the application of Ashimashi 2/100 sodium hypochlorite disinfectant. Paknaz showed the highest efficacy against HBV. Vitex and Active ranked next with significant differences [P<0.0001].Under the study limitations, Paknaz 2/100 sodium hypochlorite solution was the most effective while Ashimashi 2/100 sodium hypochlorite disinfectant did not show adequate efficacy against HBV

[Microleakage evaluation of silorane-based composites versus low shirinkage methacrylate-based composites]

Determining the best restorative material to decrease microleakage in class V restorations is of great importance in operative dentistry. The aim of this in-vitro study was to evaluate the microleakage of silorane-based composites compared to low shrinkage methacrylate-based composites in class V restorations. In this in vitro study, class V cavities were prepared on the buccal and lingual surfaces of 24 human premolars and molars [48 cavities]. The specimens were divided into four groups of 6[12 cavities] as follows: group 1 [LS System Adhesive, Primer and Bond + Filtek P90], group 2 [Kalore-GC+ Clearfil SE bond], group 3 [Clearfil SE bond + Grandio] and group4 [Clearfil SE bond + Aelite LS Posterior]. All the specimens were thermocycled for 2000 cycles [5-50°C]. The teeth were then immersed in 0.5% basic fuchsin dye for 24 hours at 37°C, sectioned and observed under stereomicroscope. Data were analyzed using Kruskal-Wallis and Wilcoxon tests at a P<0.05 level of significance. There were no significant differences in microleakage among the four groups at the occlusal margin [P>0.05]. But, there were statistically significant differences in microleakage between Silorane and Aelite at the gingival margin [P<0.05]. Statistically significant differences were also found in microleakage between occlusal and gingival margins [except for Kalore and Silorane] [P>0.05] Silorane was not superior to the conventional low shrinkage methacrylate-based composites except for Aelite in terms of microleakage

[Comparison of temperature rise in silorane-based and methacrylate-based composites cured by LED and Argon laser]

Temperature rise occurs during photoactivation of dental composites due to the exothermic polymerization reaction and different curing units. The aim of this study was evaluation of temperature rise in two kinds of composites with different curing units. In this experimental study, five samples of each composite resin [Filtek Z250, Filtek P90] were placed in two-millimeter deep Teflon molds which were 4mm in diameter. Curing was done from top surface with LED, high power LED and argon laser and temperature was recorded by a thermometer placed under the samples. After reaching room temperature, samples were cured and the temperature was recorded again. The time of maximum temperature was also recorded. The data were analyzed by two-way ANOVA and Tukey HSD. Composites and curing units had statistically significant influence on the temperature rise [p<0.001] Silorane-based composites showed significantly higher temperature rise than methacrylate-based ones. A significantly lower rise in temperature occurred when illumination was performed by argon laser. There was no significant difference in temperature rise between the two types of LEDs. The type of composite had no effect on the time of maximum temperature and in all samples the maximum temperature was recorded at the beginning of irradiation. Silorane-based composites showed higher temperature rise than methacrylatebased ones. Argon laser revealed less heat than LEDs. The maximum temperature rise was recorded at the beginning of irradiation

[In vitro evaluation of Fuji IX glass ionomer to microleakage after exposure to hydrogen peroxide 35% in class V restoration]

Fuji IX packable glass ionomer has anti-carious properties by adhesion to tooth structure. It seems to provide adequate seal between tooth structure and restoration due to the development of ionic crosslinks. Furthermore, bleaching may affect the marginal seal of restorations, subsequently increasing the leakage of oral fluids and bacteria into the restored structure. The aim was to evaluate the effect of packable glass ionomer [Fuji IX] on the microleakage of Class V restoration exposed with and without H2O2 35%. Forty sound human molars and premolars were selected and class V standard cavities were prepared on each tooth. The specimens were assigned in two case and control groups while cases were exposed to H2O2 35% for the subsequent 5 days [30 minutes each day thrice] and the controls were stored in serum physiology. The specimens were thermocycled, stained with fushin and sectioned longitudinally. The microleakage scores were determined and subjected to Mann-Whitney U and Friedman tests in both groups. The mean and median of leakage scores in four regions of control specimens were 1.588 and 1.625 while the ratios were 1.913 and 2.25 for the teeth exposed to H2O2. The teeth exposed to H2O2 35% leaked higher than control specimens in the mesial region [p<0.04], while no significant differences were observed between two groups in the other areas. The use of Fuji IX glass ionomer cements in the restoration of class V cavities is an acceptable treatment modality for the restoration of bleached teeth

[In vitro evaluation of antibacterial activity of extract of Salvia officinalis and Carum copticum against cariogenic microorganisms]

Based on the attraction of the world society to traditional treatment and the importance of drug extraction of natural material and plants, in this in vitro study the effect of hydroalcoholic extract of Salvia officinalis and Carum copticum which are very useful in the traditional treatment of mouth and teeth disease have been determined against cariogenic bacteria. In this experimental study, hydroalcoholic extracts have been prepared after sterilization of the extracts by special filter from Salvia officinalis and Carum copticum using the maceration method [serial dilution of the sample by the method]. Their antibacterial activity against Streptococcus mutans, Lactobacillus rhamnosus and Actinomyces viscosus have been evaluated by the broth macrodilution method. Results have been analyzed with Mann-Whitney test. MIC [Minimum Inhibitory Concentration] of Salvia officinalis and Carum copticum for Streptococcus mutans were 6.25 and 12.5 micro gram per milliliter, respectively, These figures were 1.56 and 6.25 micro gram per milliliter for Lactobacillus rhamnosus and 12.5 and 25 micro gram per milliliter for Actinomyces viscosus. Both extracts had inhibitory effects on growth in all three bacterial species. Salvia officinalis had a greater effect on inhibition of growth in all three bacterial species. Salvia officinalis also had a bactericidal effect in the range of concentration

Bond strength of resin cements to noble and base metal alloys after two surface treatments

The reported bond strengths of resin cements to metal alloys depend on the metal used, the conditioning methods and the adhesive resins. The aim of this study was to evaluate the bond strength of resin cements to two alloys [Degubond 4 and Verabond] after sandblasting or using Silano-Pen. Eighty disk shaped specimens [6mm diameter and 2mm thickness] of Verabond or Degubond 4 were cast according to the manufacturer's instructions. After mounting in auto polymerizing acryl, all samples were polished with a 600 grit silicon carbide paper under water. Half of each alloy's samples were randomly sandblasted with 50micro A1[2]O[3] and the other half were flamed with Silano-Pen device after sandblasting with 110 micro A1[2]O[3]. Cylinders of composite resin [Z250] were cured and then cemented to the prepared substrates by either Panavia F2 or RelyX Unicem. All specimens were stored in distilled water at 37°C for 24 hours and were subjected to 2000 thermal cycles [5-55°C], then submitted to shear bond strength [SBS] test using Universal Testing Machine at 0.5mm/min speed, until failure. SBS was analyzed by three way ANOVA [alpha=0.05]. Failure patterns were determined using stereomicroscope with 40X magnification. Both cements provided stronger bond to Verabond compared to Degubond 4 [p<0.001]. Comparing the surface treatments, Silano-Pen provided higher SBS of RelyX Unicem to both alloys. Panavia cement resulted in higher bond strengths to sandblasted Verabond alloy [p=0.003], but after treatment with Silano-Pen device RelyX Unicem showed higher bond [p=0.011]. When cementing Verabond or Degubond 4 by RelyX Unicem, Silano-Pen provided a stronger bond, but in case of using Panavia F2, treatment with Silano-Pen or sandblast resulted no difference in bond strength

[ vitro evaluation of antibacterial activity of hydroalcoholic extract of Salvia officinalis and Menta longifolia against three cariogenic bacteria]

The microbial cause of dental caries has been proved among its multifactorial etiologies. The prevention and control of dental caries is very critical because of high prevalence and cost especially in high risk patient such as xerostomia. Based on the world attraction to traditional treatment and importance of drug extraction of natural material and plants, in this in vitro study effect of hydroalcoholic extract of Salvia officinalis and Menta longifolia which were very useful in traditional treatment of mouth and teeth disease has been determined against cariogenic bacteria. In this experimental study, hydroalcoholic extracts have been prepared from Salvia officinalis and Menta longifolia with maceration method. Their antibacterial activity against Streptococcus mutans, Lactobacillus rhamnosus and Actinomyces viscosus have been evaluated with broth macrodilution method. Results have been analyzed with Mann-Whitney test. Minimum inhibitory concentration for Salvia officinalis and Menta longifolia for streptococcus mutans were respectively 6.25 and 12.5 micro g/ml, for Lactobacillus rhamnosus 1.56 and 3.12 micro g/ml and for Actinomyces viscosus 12.5 and 100 micro g/ml. Both extracts had growth inhibitory effect on all three bacteria. Saliva officinalis had greater effect on inhibition of growth of all three bacteria [p<0.05]. Both extracts had bactericidal effect in the range of studied concentrations

Effect of the thermal and mechanical load cycling on microleakage of packable composite resin

Some studies have reported packable composite has good mechanical properties including less stress, polymerization shrinkage and lower coefficient in thermal expansion, but it's adaptation to cavity walls is not so good. This study evaluated the thermal cycling and Mechanical loading on microleakage of packable composite using in-vitro method. Forty eight bovine incisors were selected; Cl II cavity preparations were performed. The teeth were etched with 37% phosphoric acid. After etching, the teeth were rinsed with distilled water and dried with cotton pellet. Single bond [3M] adhesive system was applied next according to the manufacturer's instructions. The surface was light-cured [Intensity 520 MW/cm[2] and the cavities were filled with P 60 composite [3M]. The teeth were randomly divided into two groups and two subgroups [n=12]. Each group was treated with different thermal and mechanical load cycling. The entire surface of each tooth was coated with three layers of Nail polish, except for the 1- mm width around the cervical margin. The teeth were immersed in 2% fushin solution for two hours and then embedded in acrylic resin. Then they were hemi-sectioned longitudinally in a mesio-distal direction through the center of the restoration. The half tooth specimens were evaluated according to the amount of dye microleakage by means of a 40xmagnification. Statistical analysis was conducted using SPSS software, and Kruskal-Wallis test. No significant difference was detected between the four groups [P>0.05]. According to the results of this study, thermo cycling and mechanical loading showed no effect on microleakage

[Antibacterial activity of hydroalcoholic extract of Salvia officinalis and Achillea millefolium against cariogenic microorganisms: an in vitro investigation]

There is an increasing global tendency to use traditional medicines and drug-extracts from natural plant materials. This in-vitro study was conducted in order to evaluate the cariostatic effect of hydroalcoholic extract of Salvia officinalis and Achillea millefolium. In this experimental study, hydroalcoholic extracts were prepared from Salvia officinalis and Achillea millefolium using maceration method. The antibacterial activity of these two extracts against Streptococcus mutans, Lactobacillus rhamnosus, and Actinomyces viscosus were evaluated through broth macrodilution method. Data was analyzed with Mann-Whitney test. The Minimum Inhibitory Concentration [MIC] of Salvia officinalis and Achillea millefolium for streptococcus mutans were 6.25 and 50 micro gram per milli liter, respectively. The corresponding figures for Lactobacillus rhamnosus were 1.56 and 12.5 micro gram per milli liter; and for Actinomyces viscosus the value were 12.5 and 50 micro gram per milli liter, respectively. The differences between the two extracts were statistically significant. Both extracts had growth inhibitory effect on all three bacteria. Salvia officinalis showed greater inhibitory effect on growth of all three bacteria. Both extracts had bactericidal effect in the considered concentration range

[EDTA dentin conditioning and Micro-shear bond strength using SE and SEM]

The main objective of using adhesive material is the improvement of restorative materials bonding to dentin surface in clean environment. The aim of this study was to investigate the effect of EDTA on bond strength of composite resin to dentin surface when used at different times and concentrations prior to application of adhesive systems by employing Scanning Electronic Microscope [SEM]. A total of 100 dentin samples were prepared from 50 human premolars. These samples were divided into two groups according to bonding type [Clearfil SE Bond =group I, Futurbond NR=group II] and each one was classified 5 subgroups according to time and concentration of EDTA as follows: 1 - Control. 2- EDTA 15%, 30 seconds. 3 - EDTA 15%, 60 seconds. 4 - EDTA 24%, 30 seconds. 5 - EDTA 24%, 60 seconds. These samples were conditioned and composite cylinders were adhered to them. After 500 cycles of thermocycling, the testing for micro-shear bond strength was conducted on these samples. Another 10 samples were demineralized for 30 seconds with 6NHCL and deproteinized with 2.5% Naocl for 10 minutes, air dried with desiccators and viewed under SEM. Data were analyzed using one-way as well as three-way ANOVA and Tukey tests. The mean Micro-shear bond strength in group I [Clearfil SE bond] were: 31.88 [ +/- 13] for subgroup 1, 28.4 [ +/- 13] in subgroup 2, 29.8 [ +/- 9] in subgroup 3, 29.2 [ +/- 11] in subgroup 4, and 32.7 [ +/- 12] in subgroup 5. The mean Micro-shear bond strength in group 2 [Futurbond NR]: were: 22.6 [ +/- 10] for subgroup 1, 28.5 [ +/- 9] in subgroup 2, 27.3 [ +/- 10] subgroup 3, 32.4 [ +/- 15] in subgroup 4, and 31.1 [ +/- 14] in subgroup 5. There were no significant differences between the samples conditioned and the ones not conditioned with EDTA, time and the concentration of EDTA applied and also the two bonding types. EDTA conditioning prior to use of the two bonding agents under investigation in this study did not improve the bonding strength of the self etch systems, neither did the time and the concentration of EDTA applied

[Antiviral effects of different sterilization and disinfection methods on internal tubes of dental handpiece]

Dental handpieces are the most commonly used instruments in dentistry and their cross contamination is very high due to their direct contact with blood and saliva. The purpose of this study was to evaluate the antiviral effects of formalin tablets and autoclave on internal lumens of dental handpieces. This experimental study was designed in order to evaluate the effect of different materials and methods of sterilization and disinfection on virus elimination from internal spaces and interior chambers of dental turbines. Four study groups were composed of: 1] Vacuum autoclave, 2] Non vacuum autoclave, 3] Ten Para Formaldehyde tablets, and 4] Twenty Para Formaldehyde tablets. Nine turbines were tested in each group after preliminary washing, drying and autoclaving. The internal tubes and spaces were then contaminated with Polio and Herpes Simplex virus type I. Antiviral agents and devices were used according to the manufacturers' instructions. Two cell culture samples were obtained from each handpiece, after washing them with sterile distilled water and MEM [Minimum Essential Medium]. In each group one handpiece was designated as control. The culture results were recorded after one week. Autoclaving was perfectly effective on both Polio and Herpes Simplex virus type I in all groups [vacuumed, non-vacuumed, with or without lubricant]. Formalin tablets were 100% effective only on polio virus, and in the 20 tablet group turbines without lubricant. These tablets killed the Herpes Simplex virus in all groups. According to the results of this study, autoclaving is the best method of virus elimination in dental handpiece

[Evaluation of disinifecting of 5% sodium hypochlorite solution diluted to 2:100 along with the use of disposable covers on HBV contaminated dental office surfaces and equipments]

The efficiency of disinfecting materials and procedures in removal of contamination from dental surfaces and equipments is essential. In authors' previous study, daily use of 2:100 dilution of 5% sodium hypochlorite in water and disposable covers were recommended since HBV contamination was found on semi-critical parts of the operative dentistry department. The aim of this study was to evaluate the HBV contamination following application of the recommended procedures. The study was conducted in two parts. In the first cross-sectional part, samples were collected from 17 sites of dental surfaces. In the second interventional part samples were collected from 10 sites of 9 dental and 3 sites of 2 light cure units, before and after disinfection with 5% sodium hypochlorite solution diluted to 2:100. Sterile cotton swabs moistened with sterile BSAS [Bovcine Serum Albumin in Sodium Chloride] solution were used for sampling. Samples were tested by PCR technique in Pasteur Institute, Iran. None of the samples collected in the first part of the study showed contamination. In the second part of the study, from 96 samples taken from various parts of dental and light cure units, before and after disinfecting, there was only on HBV contaminated site before disinfection which showed not contamination after disinfection. Based on the results of this study, disinfecting procedure with 5% sodium hypochlorite solution diluted to 2:100 along with using disposable covers is effective in preventing HB contamination

Postoperative thermal sensitivity reduction after amalgam fillings; A clinical evaluation and presentation of a new method

Prepared cavities are usually treated with liners prior to amalgam placement. Light cured glass ionomer [RMGI] have been widely used for this purpose. The aim of this study was to compare the effect of RMGI on decreasing postoperative sensitivity with a new method of applying self etch bonding and glass ionomer simultaneously. In a blind randomized clinical trial study, A total of 36 patients with 2 deep caries in their posterior teeth [cavities with less than 2 mm distance from pulp in radiography] were included. Diagnostic tests [cold-heat, percussion, electric pulp test] were performed for each tooth prior to final restoration. After cavity preparation, one tooth was treated by light cured glass ionomer, the next one with SE bond and glass ionomer randomly, followed by amalgam restoration. Diagnostic tests were performed three days, thirty days and three months after amalgam restoration. The statistical analysis was performed using SPSS software version 11.5 as well as Friedman and Wilcoxon signed-rank tests. In second follow up, the sensitivity to cold was significantly less than the conventional method [P < 0.05] in our suggested compound method. However, there was no significant difference between the two groups when using the other vitality tests. Using SE bond and light cured glass ionomer simultaneously was an effective new method of decreasing the postoperative sensitivity in short term, [1 month] although, there was no difference between the two groups in the long term