Experimental evaluation of the effect of zinc salt on inhibition of streptococcus mutans

Statement of the Problem: The rate of antibiotic resistance in bacteria and side effects of antibiotics and oral and teeth health care products are increasing. Therefore, researchers aim at finding new alternatives to control bacteria of den-tal caries

Purpose: The objective of this study was to investigate the inhibitory and bacte-ricidal effects of different concentrations of zinc sulfate and zinc acetate solu-tions on the main recognized agent of dental caries, Streptococcus mutans

Materials and Method: In this experimental study, different concentrations of aqueous zinc sulfate and zinc acetate solutions were prepared and the minimum inhibitory concentration [MIC] and minimum bactericidal concentration [MBC] of these salts for Streptococcus mutans were determined in compare with penicil-lin, chlorhexidine by micro-serial dilution method. In addition, the diameters of zone of inhibition for these salt solutions in four concentrations along with chlor-hexidine, as the control, were detected by the disc diffusion method

Results: MIC and MBC of zinc sulfate solution were higher than penicillin and chlorhexidine. There were not statistically significant differences between the MIC and MBC of zinc acetate solution, penicillin, and chlorhexidine. In 25 and 50 Mug/mL concentrations, the diameters of inhibition zone for zinc sulfate were more than zinc ac

Conclusion: Zinc sulfate and zinc acetate salts with 37.19 and 31.25 Mugr/mL concentration had inhibitory effect on Streptococcus mutans growth respectively, although, no priority in antibacterial activity of the studied zinc salts was deter-mined in comparison with penicillin and chlorhexidine

Antibacterial effect of calcium hydroxide on intraluminal and intratubular Enterococcus faecalis

Root canal treatment involves the elimination of intraradicular microorganisms. Calcium hydroxide [Ca[OH]2] is the most widely used canal dressing material. Enterococcus faecalis [E. faecalis] has been reported to be resistant to Ca[OH]2 in-vivo. The purpose of this study was to evaluate the efficacy of Ca[OH]2 on the elimination of intraluminal and intratubular E. faecalis. Thirty six human single-rooted teeth were contaminated with E. faecalis. Thirty specimens in the experimental group were treated with 10% Ca[OH]2; six specimens were treated with normal saline as the positive control [n=6]. Specimens from experimental group were randomly divided into two subgroups of 15 each. In subgroup A, specimens were incubated and sampled after one day and in subgroup B, they were tested at day seven. Paper points and Gates Glidden burs were used to obtain the intraluminal and intratubular E. faecalis respectively. Samples obtained from these root canal preparations were analyzed for bacterial load by counting the number of colony forming units [CFUs]. Mann-Whitney and t-test were used for analysis. Group B had significant decrease in CFUs compared with group A with both sampling methods [P<0.001]. No differences were observed between the antimicrobial properties of Ca[OH]2 against intraluminal and intratubular E. faecalis. After 1 week, there was a significant reduction in CFU load with Ca[OH]2 intra canal medication. Ca[OH]2 showed the same antimicrobial efficacy on intraluminal and intratubular E. faecalis

Assembling of fluid filtration system for quantitative evaluation of microleakage in dental materials

There are several methods for evaluating microleakage in dentistry, for example dye or bacterial leakage, electro-chemical methods, radioisotope labeling and fluid filtration. The purpose of this study was to assemble the fluid filtration system for quantitative evaluation of microleakage in dental materials. The roots were connected to a tube filled with an underwater pressure supply. A bubble was introduced into the water to measure endodontic leakage. A digital camera and professional software were utilized to record and measure the bubble displacement. Our system was constructed successfully and functioned correctly. In this pilot study we found this system efficient for the evaluation of microleakage of dental materials

External root resorption: Arrested or progressing?

External root resorptionmay be an uncontrolled phenomenon, and themost known interventions have no effect. Even progressive external root resorption may not be controlled by long term Ca[OH][2] therapy. Currently, there are no treatment options for vital tooth that suffer from root resorption. This invasive resorption can lead to extraction of the tooth. The use of new technologies such as low power laser may control this type of resorption

Diagnostic efficacy of digital and conventional radiography in periapical bone lesions

The only sign of chronic apical periodontitis is periapical lesions that are seen in radiographs. Lesions are visible when the inflammation reaches cortical plates. Lesions located in cancellous bone, cannot be easily seen in radiography. Developing computerized technology in radiography, which has numerous advantages and its show up devices in the market, encourage the clinicians to take advantage of this technology. It has accessory image processing softwares such as color spectrum. Most currently available systems provide facilities for color conversion of gray scale images. Humans can distinguish much more colors than shades of gray. The aim of this study was to evaluate the diagnostic efficacy of color conversion in diagnosing the periapical lesions located in cancellous bone. 10 premolar teeth were placed in bony sections of the cadaver mandibles. To make sure that there hasn't been any periapical lesions in sections previously, conventional radiographs were taken. In the next step, simulated periapical lesions were prepared artificially in the buccal or lingual cancellous bone. Then, direct and indirect conventional and digital images were taken. Digital black and white images were converted to colored images using the image processing system. Five observers were asked to determine the presene, location and size of the lesions. Statistical analyses revealed that color conversion of digital radiography is more accurate than black and white white digital and conventional radiography in determining the presence, location and size of the lesions. In conclusion transforming the gray values of digital images into a color spectrum can improve the detection of bone loss. This is a usefull tool for diagnosing the lesions located in cancellous bone