Antibacterial activity of ß -Tricalcium phosphate containing nanosilver particles on periodontal Gram-negative pathogen.

INTRODUCCTION: This research aimed to investigate the effect of antibacterial suspension containing TCP-ß and nanosilver on these pathogens. MATERIAL AND METHODS: Suspension containing concentrations of 4%, 2%, 1% and 0.1% was prepared with tricalcium phosphate and nanosilver. Two control suspensions for pure nanosilver and pure ß-TCP were also prepared. The antibacterial activity of this suspension was investigated on two groups of bacteria, namely, P. intermedia and Aa in thioglycolate broth environment. Subsequently, the MIC was measured for each bacterium. RESULTS: The suspension containing ß-TCP and nanosilver produced an antibacterial effect on P. intermedia and Aa. The effect of this solution on P. intermedia was greater than that on A. actinomycetemcomitans. Moreover, the MICs (mg/mL) for P. intermedia and A. actinomycetemcomitans were 1% and 0.1%, respectively. CONCLUSION: Based on the results of this study adding nanosilver particles to ß-TCP resulted in the antibacterial property of this substance. Specifically, reduced the growth rate of Aa and P. intermedia. Nanosilver can be used to reduce the risk of infection during or after regenerative surgery.

Evaluation of the antimicrobial effect of conventional and nanosilver-containing varnishes on oral streptococci.

STATEMENT OF THE PROBLEM: Nanosilver particles have the potential to serve as a bactericidal agent because of the inherent antimicrobial influences of silver ion. The literature confirmed that specific micro-organisms, especially streptococci, have an important role as an etiological factor for caries. PURPOSE: The aim of this study was to evaluate the antimicrobial effect of conventional and nanosilver-containing varnishes on oral streptococci. MATERIALS AND METHOD: Pure cultivations of Streptococcus mutans and Streptococcus salivarius were prepared on blood agar media. Thereafter, 0.5 McFarland standard of recently grown bacteria in normal saline was prepared and the bacteria were cultivated monotonously on the culture medium surface by applying a swab. Different concentrations of nanosilver varnishes were prepared in the Mueller- Hinton broth medium in the test tubes and equal amounts of 0.5 McFarland suspension of all the tested bacteria were added separately to all test tubes. A tube without varnish was included as the control sample. The tubes were kept at 37°C for 24 hours, then cultured to determine the numbers of bacteria in each tube by counting colonies. The numbers of bacteria in tubes with varnish were compared to the numbers of bacteria in the tube without varnish. In the instance of observing any reduction in the growth, the minimum inhibitory concentration for growth in the tube with varnish was determined. RESULTS: Nanosilver varnish had an antimicrobial effect on S. mutans and S. salivarius.  S. salivarius was more susceptible than S. mutans to the nanosilver varnish. CONCLUSION: Based on the results of this study, nanosilver varnishes can be used under amalgam restorations to reduce microbial population and subsequently preventing the recurrent caries.

An In vitro Comparison of Furcal Perforation Repaired with Pro-root MTA and New Endodontic Cement in Primary Molar Teeth- A Microleakage Study.

STATEMENT OF PROBLEM: One of the most challenging procedural accidents during pulpotomy of primary molars is furcal perforation. To prevent bacterial invasion, the perforation site should be sealed as soon as possible. PURPOSE: The aim of the current study is to investigate the ability of the pro-root MTA and new endodontic cement (NEC) in repairing the furcation perforations of primary molar teeth. MATERIALS AND METHOD: In this in vitro study, 42 extracted primary molars were selected. Their roots were sectioned horizontally and standard access cavity was prepared. The orifices and the root apices were sealed with two layers of resin composite.The samples were randomly assigned into 2 groups. 6 teeth were considered as the positive and the negative controls. In the experimental groups; perforation was made. In group 1 and 2, perforation site received pro-root MTA and NEC respectively. The teeth were covered by two layers of nail polish except for the external surface of the perforation site. The negative control group received no repairing material. All teeth were mounted and sterilized for 24 hours. Lower chambers were filled with sterilized Muller Hinton broth. Bacterial suspension of Enterococcus faecalis in 0.5 McFarland was prepared. The repaired site was then exposed to the bacterial suspension of Enterococcus faecalis every 3 days. All samples were inserted in an incubator at 37(o)C and 100% humidity. The turbidity of the samples was detected for a period of 30 days. Data were analyzed by Chi- square test. RESULTS: 44% of samples in Pro- root group, 50% of the samples in the NEC group showed contaminations during 30 days. There was no significant difference between these two groups (p= 0.799). CONCLUSION: With limitations of this study, Pro- root MTA and NEC showed similar capability in sealing the furcal perforations of the primary molars.

Evaluation of the Relationship between Passive Smoking and Oral Pigmentation in Children.

INTRODUCTION: Melanin pigmentation in the oral mucosa occurs as a result of several reasons one of which is smoking. Cigarette smoke induces numerous side effects in the people who do not smoke, but are in the same environment. The aim of this study was to evaluate the role of parental smoking on pigmentation of their children's oral mucosa. MATERIALS AND METHODS: This study was carried out as a historical cohort. Participants were 400 healthy children, 10 to 11 years old who did not use any drugs. The passive smoker group included 200 children who at least one member in their family was a smoker. The control group included 200 children who did not have a smoker in their family. Furthermore, two groups were matched in the point of view of skin color. The children in the two groups were examined and oral pigmentation was recorded. Finally, the results were analyzed by the chi- square test. RESULTS: Pigmentation was seen in 150 children (75%) in the experimental group and 122 children (61%) in the control group (P<0.005). The relative risk of oral pigmentation for children who were exposed to passive smoking was 1.23. CONCLUSION: Based on the results of this study, passive smoking can induce gingival pigmentation in children.