Journal of Dental Medicine

Statement of Problem: Today, cross infection control is an integral part of dentistry and many dental health care workers no longer question its necessity. All dental equipments and instruments could be potentially considered as a source of infection.

Purpose: The aim of this study was the evaluation of aerobic contaminations of four disposable materials used in routine dental practice.

Materials and Methods: In this cross-sectional study, random sampling was performed and tryptone soy broth transfer culture medium was used. After 24 hours of incubation, samples were transferred to specific culture media. (Mckangy, Chocolate agar and Blood agar). Cultured bacteria were stained and studied using gram staining method. The study was carried out in a 17 weeks period.

Results: All suction tips were infected with Bacillus cereus bacterium. Two cases of cotton roll samples showed contamination with Bacillus cereus, 2 cases with gram positive, coagulase negative cocci, 1 case with Streptococcus viridians and one case with Enterobacter class A. One case of anesthetic cartridges was contaminated with Staphylococcus epidermidis and two cases with Streptococcus viridians. Two cases of gutta-percha samples were contaminated with Bacillus cereus.

Conclusion: Based of the findings of this study, the highest level of contamination was observed in saliva ejector tips. Contamination with Bacillus cereus was seen more frequently.

Background and Aim: Care must be taken during root canal therapy to prevent contamination of filling materials and avoid root canal contamination. Gutta-percha cones are now widely used to fill root canals. However they are not resistant to conventional sterilization processes in moist or dry heat. To keep the aseptic chain, gutta-percha cones require rapid chair side decontamination before use. Considering different methods for rapid decontamination of gutta-percha cones, use of chemical agents is the best. The purpose of this study was to compare the effectiveness of three different disinfectant solutions in rapid decontamination of gutta-percha cones in one minute

Materials and Methods: In this experimental study, 360 gutta-percha cones were placed in bacterial suspensions of Staphylococcus aurous, Escherichia coli and Bacillus subtilis spore for 30 minutes, and then immersed in disinfectant solutions (Micro-10, Deconex 53 Plus, 5.25% sodium hypocholorite) for 1 minute. After that, the cones were aseptically transferred to the test tubes containing sterile saline. This solution was diluted 10-fold and then cultured on in brain-heart-infusion agar and the number of colonies was estimated after 24 h incubation at 37ْC. A series of 5 previously sterilized cones was used as negative control to check the sterility of gutta-percha cones directly from the manufacturer's box. Another series of gutta-percha cones were considered as positive control group.

 Results: No bacterial growth was seen in different test groups and negative control group.

Conclusion: Analysis of disinfectant effects of sodium hypochlorite, Micro10 and Deconex 53 plus showed that all of these solutions have bactericidal and sporocidal effect and are very efficient in surface disinfection of gutta–percha cones in one minute. Because of irritative effects and unpleasant odor of sodium hypochlorite, Deconex 53 plus and Micro10 can be used for rapid decontamination of gutta-percha cones.

Background and Aims: The purpose of this study was to evaluate the sealing ability of different thicknesses of orthograde MTA plugs in comparison with 5 mm gutta-percha.

Materials and Methods: Fifty extracted single rooted human teeth were collected. After root canal preparation, the samples were randomly divided into 4 experimental (n=10) and two control groups (n=5). In group 1, the apical 5 mm of the canals were obturated using laterally condensed gutta-percha and sealer AH26. Groups 2, 3 and 4 received 2, 3 and 4-mm thick orthograde MTA plug, respectively. Thereafter, the coronal portion of specimens was exposed to the microbial solution containing streptococcus sanguis and the root tips were placed in phenol red lactose broth. The color changes were observed within 60 days. The data were analyzed with Fisher exact test.

Results: The leakage was found in all samples (100%) in group 1 and 72.7%, 30.8% and 50% of the samples in groups 2, 3 and 4, respectively. Significant difference was found between 3 mm thickness of MTA plug and gutta percha and sealer (P=0.02).

Conclusion: According to the findings, it seems that 3 mm thickness of orthograde MTA plug had better sealing ability than the other thicknesses of MTA plug as well as the 5 mm of gutta-percha.