Tezer Ulusu

Short-term antimicrobial properties of mineral trioxide aggregate with incorporated silver-zeolite

The purpose of this in vitro study was to determine whether adding silver-zeolite (SZ) to mineral trioxide aggregate (MTA) would enhance the antimicrobial activity of MTA against Staphylococcus aureus (ATCC #25923), Enterococcus faecalis (ATCC #29212), Escherichia coli (ATCC#25922), Pseudomonas aeruginosa (ATCC #27853), Candida albicans (ATCC #90028), Porphyromonas gingivalis (ATCC #33277), Actinomyces israelii (ATCC #12102), and Prevotella intermedia (ATCC# 15032). SZ was added at 0.2% and 2% mass fraction concentration to MTA powder. The control group was MTA powder with no SZ. The antimicrobial effect test was accomplished by placing freshly mixed MTA specimens on agar plates inoculated with microorganisms and comparing the zones of inhibition at 24, 48, and 72 h. The amounts of silver ion release from MTA specimens were measured with atomic absorption spectrophotometry at 10-min, 24-, 48-, and 72-h periods. The pH of MTA specimens was measured with a pH meter at 10-min, 24-, 48-, and 72-h periods. MTA with 2% and 0.2% SZ specimens showed inhibitory effects on some microorganisms at all time periods, whereas no antimicrobial activity showed for P. intermedia and A. israelii. MTA without SZ inhibited C. albicans, E. Coli, and P. intermedia. The highest silver release was detected in 2% SZ MTA at 24 h. The incorporation of SZ may enhance the antimicrobial activity of MTA.

Effect of antibacterial agents on the surface hardness of a conventional glass-ionomer cement

In atraumatic restorative treatment (ART), caries removal with hand excavation instruments is not as efficient as that with rotary burs in eliminating bacteria under the glass ionomer cements (GICs). Thus, different antibacterial agents have been used in recent studies to enhance the antibacterial properties of the GICs, without jeopardizing their basic physical properties. Objective The objective of this study was to evaluate the effect of antibacterial agents on the surface hardness of a conventional GIC (Fuji IX) using Vickers microhardness [Vickers hardness number (VHN)] test. Material and Methods Cetrimide (CT), cetylpyridinium chloride (CPC) and chlorhexidine (CHX) were added to the powder and benzalkonium chloride (BC) was added to the liquid of Fuji IX in concentrations of 1% and 2%, and served as the experimental groups. A control group containing no additive was also prepared. After the completion of setting reaction, VHN measurements were recorded at 1, 7, 15, 30, 60, and 90 days after storage in 37ºC distilled water. A one-way ANOVA was performed followed by a Dunnett t test and Tamhane T2 tests and also repeated measurements ANOVA was used for multiple comparisons in 95% confidence interval. Results VHN results showed significant differences between the control and the experimental groups at all time periods (p<0.05 for all). Significant differences were observed between all study periods for individual groups (p<0.05). After 7 days, VHNs were decreased in all experimental groups while they continued to increase in the control group. BC and CHX groups demonstrated the least whereas CT and CPC groups exhibited most adverse effect on the hardness of set cements. Conclusions Despite the decreased microhardness values in all experimental groups compared to the controls after 7 up to 90 days, incorporating certain antibacterial agents into Fuji IX GIC showed tolerable microhardness alterations within the limitations of this in vitro study.

In vitro comparison of digital and conventional bitewing radiographs for the detection of approximal caries in primary teeth exposed and viewed by a new wireless handheld unit

OBJECTIVES The aim of this study was to compare the diagnostic quality of a new wireless handheld unit (ADX4000; Dexcowin Co. Ltd, Korea) on conventional bitewings and its LCD screen for the detection of approximal caries in primary teeth. METHODS In total, 108 approximal surfaces of primary teeth were examined in vitro by 3 observers. Conventional films were viewed under subdued lighting conditions on a conventional view box. Digital 3.5 inch images were displayed on the built-in monitor of the ADX4000 and digital 17 inch images were viewed on a 17 inch monitor. The true caries diagnosis was based on histological assessment of the approximal surfaces after sectioning the primary teeth. Receiver operating characteristic (ROC) curve (A(z)) analysis was used to assess the diagnostic quality of imaging modalities. RESULTS The areas under the ROC curves ranged from 0.786 (digital 17 inch) to 0.813 (digital 3.5 inch). No statistically significant differences were found between the three modalities for detecting approximal caries. CONCLUSIONS It was concluded that the diagnostic quality of conventional film and digital images, which were exposed and viewed by a new wireless handheld unit, was comparable.

Antibacterial effect of silver-zeolite containing root-canal filling material.

The aim of this study was to determine the in vitro antibacterial effect of two experimental glass ionomer cements (GICs) on Streptococcus milleri, Staphylococcus aureus, and Enterococcus faecalis after 24 and 48 h incubation by using the agar diffusion inhibitory test. Silver zeolite (SZ) was added at 0.2 and 2% mass fraction concentration to GIC (Endion). The control group was Endion with no SZ. Each of them were prepared to uniform size using a custom-made Teflon mold, and the GIC materials were prepared to form disks (n = 5 per group). The effect of these materials on the growth of three bacteria associated with endodontic infections was determined using the agar diffusion inhibitory test. The amounts of silver ion release from these materials were measured with atomic absorption spectrophotometry at 10 min, 24- and 48-h periods. The pH of samples was measured with a pH-meter at 10 min, 24- and 48-h periods. After the incubation period, the agar plates were evaluated and the degrees of bacterial inhibition were measured in millimeters. A comparison of the mean of the test materials was statistically different in each group of specimens (p < 0.05). Between the two tested materials 2% SZ containing GIC showed the largest zone of inhibition on the agar plates of all the tested strains (p < 0.05). The most inhibition in bacterial growth occurred in E. faecalis. Adding 2% SZ to GIC resulted in a significant increase in the silver release into deionized water. This study demonstrated that GIC had an inhibitory affect on Streptococcus milleri, Staphylococcus aureus, and Enterococcus faecalis and that adding SZ increases that affect proportional to its concentration.

The success rates of a glass ionomer cement and a resin-based fissure sealant placed by fifth-year undergraduate dental students.

AIM: To evaluate retention and caries prevention of a glass-ionomer cement (GIC) and a resin-based fissure sealant placed by fifth-year undergraduate dental students. METHODS: The study was conducted according to a split-mouth, randomised clinical trial. Children with at least one pair of caries-free permanent first molars with deep pits and fissures were included in the study. The children were selected from a population that had a high risk for dental caries. Sealant materials were applied by fifth-year undergraduate dental students on 346 fissures of the first permanent molars in 173 children. The ages of the children ranged from 7–15 years (mean 9.4). Two researchers at the clinics supervised all of the procedures. Intra-examiner reproducibility and inter-examiner reproducibility were 0.90 and 0.86, respectively, for the clinical assessment of sealant retention and caries evaluation. RESULTS: GIC sealants were completely lost in 31.9% and resin-based sealants in 16.6% (p<0.05). The total retention rates of GIC sealants and resin-based sealants were 13.8% and 20.8%, respectively. After 24 months, the caries increment was 3.4% for GIC sealants and 4.8% for resin-based sealants (p>0.05). CONCLUSIONS: The retention of GIC sealants was markedly inferior to the retention of resin-based sealants; however, GIC when used as a pit and fissure sealant was slightly more effective in preventing occlusal caries.

Salivary and Urinary Fluoride Levels after 1-Month Use of Fluoride-Releasing Removable Appliances

Forty children aged 8-10 years participated in this study. Half (n =20) of them used orthodontic appliances which contained fluoride-releasing devices embedded in the lingual surface of the appliance and the other half used orthodontic appliances prepared from a fluoride-releasing acrylic polymer. Prior to the adjustment of appliances and after 1, 7, 14, 21 and 30 days salivary and urinary samples were collected and the fluoride concentrations were determined. The mean fluoride release was highest during the first week. However, the values decreased considerably after that and the curves for the two groups became parallel. The results indicate that fluoride-releasing removable appliances could be useful for a prolonged release of low concentrations of fluoride without any systemic effect.