مسیح کاویان

One of the most common complications in the treatment of fixed orthodontics during treatment is periodontal problems. Different therapies such as mouthwashes, antibiotics and today laser therapy are used to treat periodontal problems in orthodontic patients. The aim of  this study, is that we evaluated the effect of the Diode laser on the number of four periopathogen microorganisms.

In this experimental study, 12 patients with fixed orthodontic appliance without gingivitis and periodontitis were selected. The left and right second premolar teeth were considered as case and control groups. After periodontal examinations, before and after the laser, were taken GCF sample and After 2 weeks and 6 weeks after laser irradiation, samples were re-sampled and transferred to the laboratory. Data were analyzed by Wilcoxon and Mann-Whitney statistical tests

The mean of the four kind of preopatogen immediately after laser radiation decreased significantly. (P<0.001)And this decrease continued after two weeks, but after six weeks only the mean of the number of Prevotella intermedia  (P=0.008) and porphyrpmonas gingivali (P=0.002) decreased significantly.

lasertherapy is effective in the reduction of the number of preopatogenic microorganisms in gingival crevicular fluid of fixed orthodontics patients without inflammation which this effect last for a shorter period in cases of Actinomyces comitans,Actinomyces odontolyticus

Amalgam is a safe and effective restorative material in direct restorations. One of the conservative methods for the repair of a fractured amalgam restoration is the use of adhesive materials like composite resin. Therefore the aim of this study was to evaluate the bond strength of composite resin to amalgam with the use of different bonding agents.
In this in vitro study, 52 acrylic cylinders were made and amalgam containing 43% Ag was condensed into these cylinders. After keeping the amalgam samples at room temperature for 24 hours, the amalgam surfaces were abraded with a diamond bur and all the samples were immersed in an ultrasonic bath. Then the specimens were divided into 4 groups of 13 samples, and each group was treated with different boding agents as follows: group (1), amalgam alloy primer total etch (Single Bond); group (2), amalgam alloy primer self-etch (G Bond); group (3), amalgam G Bond; and group (4), amalgam Single Bond. Composite resin was bonded to prepared amalgam specimens with the use of translucent polyethylene mold and cured by LED Turbo, followed by testing with an Instron machine for shear bond strength. Finally data were analyzed with one-way ANOVA and LSD tests.
In this study, the highest bond strength value was recorded in specimens bonded with G Bond bonding agent (9.06 MPa) and the lowest value was recorded in specimens bonded with Single Bond bonding agent (5.14 MPa). The mean shear bond strength values in 4 groups exhibited statistically significant differences (p value = 0.001).
G Bond bonding agent yielded higher bond strength between amalgam and composite resin than other bonding agents used in this research.

Sandwich technique is one of the most common methods in dentistry in which resin-modified glass ionomers due to advantages such as fluoride release and adhesion to tooth structure are used with composite restorations. The aim of this study is assessment of shear bond strength between resin modified glassionomer and composite using different bonding agents.
Material and In this invitro study, 60 resin modified glass ionomer samples (GC FUJI 2LC) were prepared. .In the first group, without the use of bonding agent and in other two groups with the use of bonding agents( SE bond and S3 bond) composite adhered to glass ionomer.After placing the samples in distilled water in incubator with temperature 37/5° C for one week, shear bond strength of samples was measured by the universal machine test . One way analysis of variance and Tukey test were used for analyzing the data and comparison between groups.
The maximum amount of the bond strength was for specimens bonded with SEbond(13/09 Mpa) and the lowest amount was in control group(5/3 Mpa) . The mean shear bond strength was significantly different between the four groups.(p The maximum shear bond strength between resin-modified glass ionomer and composite resin was related to SE bond therefore using of this bonding agent in sandwich technique is recommended.

Sandwich technique is one of the most common methods in dentistry, in which resin-modified glass ionomers are used with composite restorations due to special features, such as fluoride release and adhesion to tooth structure. This study aimed to assess shear bond strength between resin-modified glass ionomer and composite using bonding agents with different solvents.
In this in vitro study, 80 resin-modified glass ionomer samples (GC FUJI 2LC) were prepared. Composite was adhered to glass ionomer without the use of bonding agent in the first group and with the use of bonding agents in other three groups (single bond, one step plus and TG bond). After preserving the samples in distilled water in incubator at the temperature of 37.5°C for one week, shear bond strength of the subjects was measured using universal testing machine. Data analysis and comparison of the groups were performed using one-way analysis of variance and tukey post hoc.
In this study, the maximum amount of bond strength was observed in TG bond group (12.99 Mpa), whereas the lowest amount was found in the control group (5.3 Mpa). Results revealed a statistically significant difference between the groups in terms of mean shear bond strength (P=0.001).
According to the results of this study, the maximum shear bond strength between resin-modified glass ionomer and composite resin was related to TG bond. This could be due to the presence of water in the composition of bonding agent, which acted as a moisturizing agent of glass ionomer and led to greater adhesion of composite to glass ionomer.

Today, the high silver amalgam has been mentioned because of its appropriate properties so purpose of this study was the evaluation of bond strength of composite to high silver amalgam by using different bonding agents.
Methods and materials: In this experimental study, 52 acrylic cylinders were made and amalgam which contains of 60%Ag were condensed into this cylinders, amalgam surfaces were roughened by diamond bur and all samples were immerged in ultrasonic bath. Then specimens divided into 4 groups of 13 samples: group (1) Amalgam Alloy primer single bond, group (2) Amalgam Alloy primer G.bond, group (3) Amalgam single bond .bond, group (4) Amalgam G.bond. Resin composite was bonded to prepared amalgam specimens by using translucent polyethylene mold and cured by LED Turbo and tested by universal testing machine for shear bond strength and finally data were analyzed with one-way analysis of variance and LSD test.
In this study, the greatest values of bond strength were related to bonded specimens of use of Alloy primer G.bond bonding agent and lowest values were related to bonded specimens use of single bond bonding agent and mean shear bond strength in 4 groups had statistically significant difference (P=0.002).
Combination of alloy primer and G.bond. bonding agent increased the bond strength between composite and high silver amalgam significantly

Digital radiography systems can be used to detect dental caries. These systems have the advantage of reducing patient dose. The purpose of this study was to compare digital photostimulable phosphor plate, charge coupled device and cone-beam computed tomography systems in detection of interproximal demineralization.

In this cross-sectional analytical laboratory study, sixty extracted human teeth with sound mesial and distal surfaces were selected. Using a ¼ round bur (0.5 mm in diameter) cavities were prepared to a depth of 0.25 mm just apical to the interproximal contact point on 15 surfaces of teeth. A ½ round bur (0.6 mm in diameter) was used to prepare cavities to a depth of 0.3 mm on 15 surfaces and a #1 round bur was used to prepare cavities 0.4 mm in depth on 15 surfaces. The teeth were mounted in groups of three in wax blocks. The images were captured by digital CBCT, PSP and CCD systems under a standard condition. One oral radiologist observed the images to detect interproximal defects twice three weeks apart. Then, sensitivity and specificity were calculated and Cochran test was used for statistical analysis with SPSS 20).α=0.05).

The sensitivity rates of CBCT, PSP and CCD systems for the detection of lesions measuring 0.25 mm in depth (incipient caries) were 100%, 93.3% and 86.7%, respectively (p value = 0.22); there was no differences between the systems in the detection of deeper lesions (100%). There was a high agreement rate between the radiographic systems evaluated and the gold standard in the detection of lesions with varying depths (CCD=94.4% and CBCT/PSP=100%). Specificity of all the systems was 100%.

Under the limitations of this study, there were no significant differences between CBCT, PSP and CCD digital radiographic systems in the detection of interproximal demineralization. The specificity of all the three systems was the same.

Statement of problem: 

Self etch acidic primers may be unable to etch the enamel and penetrate the thick dentinal smear layer and as a result produce inadequate bond strength.

The present study aimed to evaluate the effect of the second layer application of two self-etch primers on etching pattern and micro-shear bond strength to the enamel and dentin.

In an experimental study, 104 human premolar teeth were divided into two groups. The buccal surfaces of the teeth were prepared for enamel and dentinal evaluation. Self-etch primer of clearfil SE Bond and clearfil S3 Bond were applied in one or two layers on the prepared enamel and dentin surfaces. One specimen of each prepared group was selected for SEM group evaluation. The composite resin cylinders were bonded to the rest of the specimens for micro-shear bond strength measurement. The data were analyzed using two- way ANOVA and HSD -Turkey's tests. 

Application of the second layer had no significant effect on micro-shear bond strength to the enamel and dentin (p>0.05). The dentinal micro- shear bond strength values of the specimens treated by Clearfil SE Bond, were significantly higher compared to Clearfil S3 Bond (p< 0.05) but no significant effect was found on enamel bond strength (p> 0.05).

Application of one layer of self- etch primer produced sufficient bond strength and there is no need to apply the second layer.