Genotoxicity evaluation of dentine bonding agents by comet assay.

AIM: To evaluate the genotoxicity of four different adhesives, Clearfil SE Bond, SL Bond, i Bond and Clearfil Protect Bond and the primers of Clearfil SE Bond and Clearfil Protect Bond. METHODOLOGY: Genotoxicity assessment of the adhesives and primers was carried out in vitro in human lymphocytes at different elution concentrations, using the alkaline single-cell gel electrophoresis technique (comet assay). After the incubation of lymphocytes with varying volumes of the test agent, cells were embedded in a low-melting-point agarose suspension and then lysed in alkaline (pH>13) conditions. Electrophoresis was performed on the suspended lysed cells followed by visual analysis with staining of DNA. Fluorescence was than calculated to determine the extent of DNA damage using imaging software. Statistical comparison of the results was carried out by one-way analysis of variance (anova). RESULTS: A significant increase (P<0.001) compared to untreated controls in DNA damage was observed with 'Clearfil Protect Bond' and 'Clearfil SE Bond' primer in human lymphocytes at concentrations of 2.5 and 5.0 mg mL(-1). Clearfil Protect Bond and Clearfil SE Bond adhesives induced significant (P < 0.001) DNA damage only at the higher concentration of 5.0 mg mL(-1) . No significant increase in DNA damage was observed with SL Bond and i Bond. No significant DNA damage was observed with any dentine bonding agents at the lower concentration of 1.25 mg mL(-1) . CONCLUSIONS: 'Clearfil Protect Bond' and 'Clearfil SE Bond' primers/adhesives increased DNA damage in human peripheral lymphocytes in high doses.

Microleakage of light-cured resin and resin-modified glass-ionomer dentin bonding agents applied with co-cure vs pre-cure technique.

This in vitro study evaluated the effect of dentin bonding agents in reducing microleakage after three months in Class V restorations restored with Z100 resin composite. Materials tested were three types of resin-based dentin bonding agents: a multi-step (Scotchbond Multi-Purpose); a one-step (Scotchbond One-Step); a self-etching, self-priming (Clearfil Liner Bond) and a resin-modified glass ionomer (GC Fuji Bond LC). Class V cavity preparations with occlusal margins in enamel and gingival margins in cementum were prepared both on labial and lingual surfaces of extracted premolar teeth. Restorations (two per tooth) were distributed randomly into nine test groups (n = 10) consisting of the various DBAs applied with co-cure and pre-cure techniques, and no dentin bonding as a negative control group. Samples were stored in saline for three months, thermocycled, stained with silver nitrate, then sectioned through the middle of the preparation to facilitate the removal of the composite resin restoration. For groups treated with the pre-cure technique, the differences between the enamel leakage values of SBMP-control, CFLB-control and SB1S-control subgroups were significant (p < 0.05). For enamel leakage values of groups treated with the co-cure technique, the differences between the SBMP-control, SB1S-control, CFLB-control and Fuji LC-control subgroups were significant (p < 0.05). For cementum leakage values of groups treated with pre-cure technique, the difference between the CFLB-control and the Fuji, SBMP and SB1S groups was significant (p < 0.05). No significant differences could be detected between the cementum leakage values of groups treated with the co-cure technique (p > 0.05). The differences between the values obtained with application of CFLB with the pre-cure and co-cure techniques at the cementum margins were found to be statistically significant (p = 0.02). No statistically significant differences could be detected between the pre-cure and co-cure values of the other test materials. Generally for every group, cementum microleakage values were greater than enamel microleakage values (p < 0.05). The use of Scotchbond Multi-Purpose, Scotchbond One-Step and Fuji Bond LC with the co-cure technique to decrease the application time did not cause any significant increase in microleakage. Only pre-curing using Clearfil Liner Bond provided better microleakage properties than the other pre-cured adhesives.

Lactate dehydrogenase activity in periodontal ligament cells stored in different transport media.

BACKGROUND: Maintaining viability of periodontal ligament cells is important after an avulsion injury occurs. OBJECTIVE: This study examined cell death and compared different transport media at varying times. Lactate dehydrogenase (LD) measurements were made on root surfaces of extracted teeth for evaluating the results of breakdown and necrosis of periodontal ligament cells. STUDY DESIGN: Teeth were divided into three groups. Each was immersed in one of the following storage media: Hanks balanced salt solution, Custodiol solution (an organ storage medium), or sterile saline solution. I.D. measurements (an indicator of cell death) were made at 2, 6, 24, 72, and 168 hours after extraction. RESULTS: When the LD levels were compared according to the time periods, a progressive increase of cell death was found to be statistically significant (p < 0.001). However, when the effects of both time periods and the kind of storage medium on the LD levels were examined, the LD levels of the saline solution storage medium were found to be significantly higher (p < 0.001) than that of the other two groups. CONCLUSIONS: Both Hanks balanced salt solution and Custodiol appeared to be suitable transport media for maintaining cell viability, whereas saline solution was not.

Comparison of the sealing efficacies of two obturation techniques in curved root canals instrumented with and without ultrasonic irrigation.

Volumetric dye penetration into the canals of 131 teeth was studied spectrophotometrically. The teeth were first divided into three groups according to the degree of curvature. Each group was then subdivided into four groups, in which the Thermafil and lateral condensation techniques were used with or without ultrasonic irrigation. Significant microleakage differences were observed between group I (0-10 degrees) and group III (21-30 degrees) for lateral condensation filling with ultrasound irrigation and Thermafil filling without ultrasound irrigation (p < 0.05).

Cytotoxicity versus antibacterial activity of some antiseptics in vitro.

Through the development of new techniques for bacterial growth and isolation, obligate anaerobes have been shown to be more prevalent than previously thought in the pathogenesis of periapical and pulpal diseases. A follow-up study was conducted to examine the germicidal effect of 0.05% NaOCl, 10 mg/ml metronidazole and supernatant of Ca (OH)2 (0.025 ml) on four anaerobic microorganisms commonly found in root canals, and to compare the toxicity of these substances on cell cultures. In vitro testing revealed that 0.05% NaOCl and Ca (OH)2 were both equally effective on these anaerobes. Also, metronidazole was found to be germicidally effective against Bacteroides melaninogenicus, Bacteroides oralis and Peptostreptococcus anaerobius, but ineffective against Veillonella alcalescens. Furthermore, it was found that NaOCl and Ca (OH)2 had a very destructive effect on cell cultures compared with their antimicrobial effect, whereas metronidazole was less toxic among the agents tested.

Evaluation of diagnostic radiopaque contrast materials used with calcium hydroxide.

An evaluation of three different radiopaque materials used in combination with calcium hydroxide powder for diagnostic contrast was made. Diatrizoate meglumine (65%) and iothalamate meglumine (60%) compared favorably with barium sulfate (35%). Since barium sulfate has demonstrated problems by altering the manipulative properties of calcium hydroxide as well as demonstrating a residual radiopacity, there may be advantages to the use of resorbable diatrizoate or iothalamate compounds as alternatives. These soluble iodine compounds also make possible an excellent aqueous medium in which to mix calcium hydroxide.

[The dental picture and maxillo facial skeletal morphology in idiopathic hypoparathyroidism (a case report)]. / Idiyopatik hipoparatiroidide dis bulgulari ve çene-yüz iskelet morfolojisi (Bir vaka raporu).

In this paper a case showing idiopathic hypoparathyroidism with its rare dental findings were presented. Abnormalities belonging to maxillo-facial skeletal morphology was also evaluated by means of cephalometric analysis.

[An evaluation of the antibacterial effectiveness of bisdequalinium acetate and sodium hypochlorite]. / Bis-deqalinium asetat ve sodyum hipoklorid solusyonlarinin antibakteriyel etkinliklerinin degerlendirilmesi.

The antimicrobial effectiveness of sodium hypochlorite and bis-dequalinium acetate was evaluated in vitro using three different microorganisms. The solutions were prepared in various concentrations and microorganisms were exposed to these solutions for 5, 10, 15 min. then placed into a culture medium, incubated and determined the presence or absence of growth. These results were compared with those obtained with phenol. The following conclusions were drawn from this study: 1. Of the solutions tested Bis-dequalinium acetate was the most effective antimicrobial agent. And 1.25/1000 Bis-dequalinium acetate is appropriate for the clinical use. 2. Sodium Hypochlorite is the least effective compared with Bis-dequalinium acetate and phenol. 2/100 NaOCl is agreeable for the clinical use. 3. Normal saline exhibits no antimicrobial properties.