ABSTRACT
Considering the increasing use of antibiotics in root canal therapy and the possible effects of intracanal medicaments on the bond strength of composite restorations, the aim of this study was to evaluate the effect of triple antibiotic paste on shear bond strength of three types of composite resins to dentin.In this in-vitro, experimental study, the enamel of 60 extracted premolars was ground parallel to the longitudinal axis of the teeth in order to produce flat dentin surfaces [5 mm[2] minimum surface area]. The samples were divided into six groups. In the control group, dentin surfaces were stored in saline solution and in the experimental groups, dentin surfaces were exposed to triple antibiotic paste for 10 days. After washing and drying, Single Bond was applied for dentin bond to Z100 and Z350 composites. Adhesive resin was used for bond to to P90 composite. Composites were applied on the dentin surfaces in six groups and cured in four directions. The shear bond strength was measured by Instron machine. The data were analyzed by t-test, one-way ANOVA and Tukey's test. The highest mean shear bond strength was found in Z350 composite group following the use of triple antibiotic paste [38.75 MPa] and the lowest mean strength was found in Z100 composite group following the use of triple antibiotic paste [14.64 MPa]. The mean shear bond strength of P90 and Z100 composites [in contrast to Z350 composite] was higher in the saline compared to the triple antibiotic paste groups [P=0.1]. The differences between saline and antibiotic groups were not significant [P=0.959] but the difference in this regard among the three types of composites was significant.The results of this study showed that use of triple antibiotic paste has no effect on the shear bond strength of composite to dentin but the type of composite significantly affects the shear bond strength
ABSTRACT
Dental unit water Systems [DUWS] have been demonstrated to be contaminated with biofilms. This biofilm could be a site for growth and colorization of pathologic microorganisms. The aim of this research was to measure the Total Cultivable Flora [TCF] in DUWS of Khorasgan dental school and the effect of stabilized chlorine dioxide on its reduction. In this research, 60 samples of water from high speed turbines, air-water syringes, cabitrons and wash basins were collected. The samples were cultured in agar nutrition media and incubated for 5 days. After the incubation period, colonial counting was done by HPC method. In the next stage, stabilized chlorine dioxide was added in a container for each unit and ethic samples were taken from air-water syringes, cabitrons and turbine outlets. As for the first stage, after 5 days of culture and incubation, the samples were observed under microscope for counting the bacterial colonies. Kruskal-Walis and Mann-Whitney tests were used for statistical analysis. A high level of bacterial contamination [more than 200 CFU] was observed in high speed turbines, air-water syringes, cavitrons and wash basins. The highest colonial count was observed from cavitron and the lowest from washbasin outlets but the difference was not statistically significant. After using chlorine dioxide, the amount of bacterial colonies was significantly reduced [p < 0.05]. The amount of bacterial contamination in DUWS of Khorasgan dental school was higher than the accepted level. These bacteria were mainly opportunistic. The addition of an anti-bacterial agent in the DUWS will significantly reduce the bacterial count to an acceptable level
Subject(s)
Equipment Contamination , Chlorine Compounds , Bacteria , Water MicrobiologyABSTRACT
Problems like perforation of furca may happen in root canal therapy. The material used for sealing of perforation is important in control of inflammation and periodontal repair. Previous studies show that ProRoot is the best material for treating these cases but is too expensive. Recently one Iranian material which is called cold -ceramic is produced in Yazd University. The aim of this study is to compare the histologic effects of cold ceramic and pro-root in healing of periodontal tissues after sealing of furcation perforation in dog teeth. Thirty five premolars of one year old dogs were used. After anesthesia by injection of lidocaine, access cavity was prepared and root canal was filled by gutta percha and AH [26] sealers with step-back technique. Then the furca was perforated 3X3 mm with long burs and washed by physiologic serum. The perforated zones were sealed randomly by pro-root and cold ceramic and the cavity was filled with amalgam. Six teeth were considered as positive and negative controls. Two dogs after one month and two after two months were sacrificed by vital perfusion. Jaws and teeth were separated and put in formalin 10%. After laboratory procedures, the samples were investigated by microscope. The data was analyzed by Mann - whitney and Kruskal - wallis tests. The results showed that ProRoot caused more repair in the same condition but there was no significant difference between the two materials after one and two months. Considering the lower price and availability of cold ceramic, if other tests are confirmed, cold ceramic may be a suitable substitution for ProRoot