مجله تحقیق در علوم دندانپزشکی
سال سیزدهم شماره 2 (پیاپی 48، تابستان 1395)

One of the major concern for dentists and oral surgeons is the impossibility of bleeding time (BT) evaluation during surgical procedures at dental office. The aim of this study was to compare BT of buccal mucosa with standard IVY method.
The descriptive research was conducted on 20 samples. All patient who had surgical indications, participated in this study. Patients were tested using both the Lancet insertion into the buccal mucosa and the IVY method. The Lancet was inserted into the buccal mucosa at the standard depth. The bleeding stop-time measured and documented. For IVY method, Sphygmomanometer was strapped around the upper arm of the patient, increased the pressure to 40mg Mercury and maintained this pressure throughout the test period. Then, inserted the Lancet and started the timer, blotting paper was used to wipe away the blood every 30 seconds until bleeding stops and recorded BT. The insertion depth of the Lancet and the IVY depth were consistent. Data was registered separately and statistically analyzed using T-test.
BT were 156± 52.05 and 80±27.57 sec for IVY and mucosal methods, respectively. Which was 76 sec more or approximately twice for mucosal method in respect to IVY method. (p It seems, mucosal BT is a suitable method for evaluation of hemostasis and BT but more research is need

Corrosion may be a consequence of disinfecting and cleansing of partial denture chromium – cobalt frameworks using chemical disinfectants and cleansers. There is short information in literature about the effect of these solutions, in comparison with each other, on the corrosion rate of chromium – cobalt alloy. The present study was designed to compare corrosion rate of the chromium – cobalt alloy in disinfecting solutions.
Material & In this experimental in-vitro study, corrosion rates of 35 chromium-cobalt immersed in7disinfecting solutions were determined. As a complementary test , samples were immersed in two groups of solutions which showed the least and the most corrosion rates as measured by electrochemical tests for a period of one week and their surface and also surface of one untreated control sample was photographed under a scanning electron microscope . Corrosion rates obtained, were statistically analyzed using variance analysing test and multiple comparisons were made using Tukey HSD and Dunnett tests.
The corrosion rates of chromium cobalt sample in the studied solutions from the highest to lowest , were : Sodium Hypochlorite 1%, Fittydent 1 tab/250ml , Micro 10 5% , Korsolex Plus 3% , Deconex 53 Plus 2% . Corrosion rates were statistically different in the studied solutions (P The present study indicated that Sodium Hypochlorite at the concentration of 1% or more for the purpose of disinfection and cleansing of chromium-cobalt not be used.

Increase of enamel roughness after bleaching is a problem of these kinds of treatments which decrease enamel resistance to dental caries and absorption of stains. The aim of this research was to compare the ability of two remineralizing agents (MI PASTE PLUS, REMIN PRO) and natural saliva on roughness of the bleached enamel in Dental branch of Tehran Islamic Azad University in 2014.
In this experimental in vitro study, 45 enamel specimens of extracted premolars were treated by XTRO (BOOST). The samples were randomly divided into three groups of 15 samples and inserted in MI PASTE PLUS, REMIN PRO and natural saliva. Enamel roughness of samples was measured at the beginning of the study, after bleaching and after the pastes application by profilometer. Data analysis done with Repeated Measured statistical method.
This research which was conducted on 45 samples revealed that, the difference of saliva group MI paste and Remini Pro were -0.08, -0.157 and -0.14, respectively.(P MI paste and Remin pro could decrease the enamel roughness also did the saliva .Remin pro could decrease the enamel roughness more effectively than MI paste , Also the natural saliva decreased the enamel roughness more than MI paste

To ensure root canal treatment success, endodontic microbiota should be efficiently reduced. Several irrigation devices have been recently introduced with the main objective of improving root canal disinfection .The purpose of this study was to evaluate the rinsing effect of RinsEndo system in reduction of enterococcus faecalis in comparison with conventional hand syringe in infected root canals.
Method and Materials: In this experimental study,60 extracted single root and single canal anterior teeth were infected with enterococcus faecalis and divided into 3 groups: RinsEndo system, conventional hand syringe and control group. The enterococcus faecalis colonies were counted in each group before and after rinsing. Data was analyzed with parametric tests such as ANOVA and nonparametric test like KrusKal Wallis.
The mean of enterococcus faecalis growth after rinsing was 3.50×103 in group with conventional syring rinsing, 2.04×103 in group with RinsEndo washing and 6.11×103 in control group. Reduction of enterococcus faecalis after rinsing was statistically significant in each group (P Rinsing with RinsEndo system is significantly more efficient in reduction of enterococcus faecalis from root canal in comparison with hand syringe washing.

Composite Resins with different chemical structure are affected by lots of stimulus within mouth's environment that make them degenerated by the time, change their characteristics. The purpose of this research is to evaluate the effect of five different Food-Stimulating liquids on water sorption and the solubility of Methacrylate and Silorane based Composite resins.
Methods and materials: In this in vitro study, twenty five discs with 1mm thickness and 6mm diameter were prepared by filling aluminum molds with two kinds of composites, Filtek Z350 and P90. Samples were light- activated from top surface, then stored in coded dishes with silica gel, and transferred to the oven with 37c̊ to desiccate them for 24h. Samples were weighed by digital balance (M1) after 24h, and then stored in five Food-Stimulating liquids (Acid citric %2 N, distilled water, Ethanol %75, Heptan, and artificial saliva). After one week, samples were weighed again and the result (M2) was recorded. Samples were placed in silica gel containers until the mass variation became less than ±0.1mg (M3). After last desiccation to get the V (body mass) of samples, the diameter and the thickness of discs were calculated. Results were analyzed with Tukey test.
Results In this research, the solubility of composite Z350 in heptan was the highest (0.040 µg/ mm³) and in distilled water had the lowest solubility (0.009 µg/ mm³).Differences between distilled water, alcohol and heptan were statistically significant (p0.05). The amount of solubility of P90 in different solutions had no statistically significant difference (p>0.05). But, water sorption in artificial saliva was higher than other solutions (P The results showed that solubility of P90 was lower than Z350 but there is no statistical difference between water sorption of two materials.

Dental injection is one of the major reasons of fear in children. Electronic dental anesthesia (EDA) is a method for performing dental local anesthesia. The purpose of this study was to evaluate the effectiveness of electronic dental anesthesia (EDA) in comparison with conventional injectable local anesthesia in 5 to 7 years old children at Pediatric department of Tehran Dental branch, Islamic Azad University.
Twenty 5 to 7 years old children were selected for participation in this clinical trial study. Each selected child had two antimere maxillary first or second primary molars requiring class II cavity preparations. One tooth was treated by conventional local anesthesia. The antimere tooth was treated by electronic dental anesthesia at the next week. At the end of the each session, rating of pain were recorded using Wong-Baker FACES® Pain Rating Scale. Mann–Whitney U test was used to determine any statistically significant difference between two techniques at a level of P Pain rating for first primary molar in EDA method was less compared to local infiltration although the difference was not statistically significant (P = 0.63). For Second primary molar, pain rating in local infiltration was significantly higher compared to EDA technique (P = 0.023).
EDA technique is an effective method for performing restorative procedures for maxillary primary molars in 5 to 7 years old patients, especially in needle-phobic children.

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

Root resorption is one of the most difficult diagnostic problems in endodontic treatment. Since successful treatment depends on early diagnosis of this pathology, using several diagnostic methods such as radiographic images based on films, digital images and advanced diagnostic techniques such as Cone Beam CT are important. Therefore, in this study, we compared digital radiography images with PSP detector with CBCT images in diagnosis of these lesions.
Material and In this in-vitro study, 45 single rooted intact teeth were sectioned in mesiodistal direction and internal resorption in the apical, middle and cervical region of tooth was made. Both group teeth were imaged with digital periapical radiographies (Digora ® Optime PSP System / Sordex) and CBCT (Newtom VGi -Italy). Analysis of periapical and CBCT images of the teeth at each site were evaluated by an experienced observer. Positive and negative predictive values ​​for each imaging technique were calculated using T-Test; and chi-square test was used to compare two different imaging techniques and the location of the resorption by using SPSS 19 software.
In overall, CBCT images showed significantly higher agreement (p According to this study, it seems, CBCT images compared with digital periapical radiography, have less errors in the detection of internal root resorption lesions, especially in apical region,