Abstract: The aim of this study was to evaluate the effects of 3 dentin bonding agents on cell survival and proliferation and on cell cycle progression of cultured cells. The experiments were performed on RPC-C2A and L929 cells. Specimens of the 3 dentin bonding agents (Clearfil Tri-S, AdheSE, and XP BOND) were placed in culture medium, and the extraction media were applied to cells as experimental material. The effect of the bonding materials on cell survival and proliferation was assessed by a modified sulforhodamine B staining assay, and the effect on DNA synthesis was assessed by bromodeoxyuridine uptake. Flow cytometry was used for cell cycle analysis. Cell viability and proliferation decreased in a dose-dependent manner after exposure of cells to the tested materials. XP BOND expressed the highest activity of all tested bonding agents (P < .05). The self-etch bonding agents tested did not produce any significant effects on cell cycle distribution. However, exposure of cells to the total-etch agent XP BOND induced a G(2)-phase arrest in both cell lines, and this effect was more evident in L929 cells than in RPC-C2A cells.

Abstract: OBJECTIVES: The purpose of this study was to evaluate the cytotoxic effect of six dental adhesives (Admira Bond, Clearfil Liner Bond 2V, ED Primer II, Fuji Bond LC, Gluma Comfort Bond, and NanoBond) applied to cell cultures. METHODS: The experiments were performed on two cell lines, rat pulp cells (RPC-C2A) and human lung fibroblasts (MRC5). Samples of the adhesives were light-cured and placed in culture medium for 24 hours. The extraction media was applied on the RPC-C2A and the MRC5 cells. Complete medium was used as a control. Cytotoxicity was evaluated with a modified sulforhodamine B (SRB) assay after 24 hours of exposure. RESULTS: The cell survival of RPC-C2A cells exposed to Fuji Bond LC, NanoBond, Clearfil Liner Bond 2V, ED Primer II, Admira Bond and Gluma Comfort Bond was 73%, 67%, 50%, 20%, 18% and 5% respectively, relative to the cell survival with the control medium. In the MRC5 cell line, the relative survival was 98%, 80%, 72%, 41%, 19% and 7% after exposure to NanoBond, Fuji Bond LC, Clearfil Liner Bond 2V, ED Primer II, Admira Bond and Gluma Comfort Bond, respectively. CONCLUSIONS: Different types of dental adhesives showed different cytotoxic effects on cells in vitro. The self-etch adhesives were superior in terms of cytotoxicity. The different cytotoxic effects of dental adhesives should be considered when selecting an appropriate adhesive for operative restorations.

Abstract: Clearfil Protect Bond is a new dental bonding agent recently introduced into clinical practice. It contains an antibacterial monomer that contributes to its antibacterial profile. The aim of the present study was to evaluate cytotoxic effect of Clearfil Protect Bond against three established fibroblastic cell lines, in comparison with four commonly used adhesive materials (Adper Scotchbond 1, Excite, Tyrian SPE, and One Step plus). The experiments were performed using RPC-C2A, BHK21/C13, and MRC5 cell lines. Test specimens, either cured or uncured, were placed in a culture medium and the extraction media were used as experimental material. The effect of the bonding materials was assessed by a modified sulforhodamine-B assay after 24 and 48 h of exposure. All tested agents exhibited an antiproliferative effect on cells, the effect on RPC-C2A being the most marked. Extraction media from the uncured materials were without exception highly cytotoxic. In the experiments performed using extraction medium from cured material, Clearfil Protect Bond appeared to be the least toxic material, followed by Tyrian SPE and One Step plus. Adper Scotchbond 1 and Excite exhibited the strongest cytotoxic effect. The cell survival percentage ranged between 66 and 97% for Clearfil Protect bond, 15 and 82% for Tyrian SPE, 28 and 58% for One Step plus, 2 and 28% for Excite, and 1 and 6% for Adper Scotchbond 1. Taking into consideration the limitations of an in vitro study, our results indicate that the new antibacterial dental adhesive system is suitable for clinical application.

Abstract: The purpose of the present in vitro study was to compare the cytotoxic effect of two commercially available brands of mineral trioxide cement (ProRoot MTA and MTA Angelus), modified zinc oxide-eugenol cement (SuperEBA) and resin-modified glass ionomer cement (Vitrebond) using rat pulp cells (RPC-C2A) and human lung fibroblasts (MRC-5). The cells were cultured in typical culture conditions and exposed to the tested materials by adaptation of insert wells. The cytotoxic effect was recorded at two observation periods (24 and 72 h) by using a colorimetric assay of tetrazolium reduction (XTT method) in reference to controls. Overall, the degree of cytotoxic effect in ascending order was ProRoot MTA - MTA Angelus < SuperEBA < Vitrebond. Both MTA materials tested exerted mild suppression of cellular mitochondrial activity and may be characterized as biologically inert materials.

Abstract: Resilon is a new material that is a candidate to replace gutta-percha as a root filling material. This study evaluated the antiproliferative effect of Resilon and two commercially available gutta-percha points (Roeko, Dentsply). Two established cell lines (L929 and RPC-C2A) were used for the experiment. Cell survival fraction was estimated by the sulforhodamine-B assay, in reference to controls after 48-h exposure. Non-parametric tests (Kruskal-Wallis followed by Dunn's multiple comparisons) were used to evaluate the statistical significance of the results (alpha=0.05). Cytotoxicity in a descending order was: Resilon > Roeko gutta-percha > Dentsply gutta-percha. At 24-h exposure, no statistically significant differences (p>0.05) were observed between tested materials in both cell lines. At 48-h exposure, statistically significant differences (p<0.05) were found between Resilon and the other materials in the L929 cell line. In the RPC-C2A cell line Resilon was significantly more cytotoxic than Dentsply gutta-percha (p<0.05), but no statistically significant differences (p>0.05) were found between Resilon and Roeko gutta-percha. The cytotoxicity of Resilon increased significantly from 24 h to 48 h in both cell lines. Resilon points were more cytotoxic than gutta-percha points. The cytotoxicity was time dependent and increased after 48 h.

Abstract: An important requirement for dental materials placed in direct contact with living tissues is biocompatibility. The purpose of this study was to evaluate the antiproliferative activity of three dental materials (mineral trioxide aggregate, zinc oxide-eugenol cement, and glass-ionomer cement) against a panel of established fibroblastic cell lines (L929, BHK21/C13, and RPC-C2A). The materials were prepared according to the manufacturer's instructions and were tested in insert wells for 12, 24, and 48 h. Cell number fraction was estimated by the sulforhodamine-B assay, in reference to controls. The degree of antiproliferative effect in ascending order was mineral trioxide aggregate, glass-ionomer cement, and zinc oxide-eugenol cement in all cell lines tested.

Abstract: The cytotoxicity of six dentin bonding agents (Syntac, Solobond, Bond 1, Scotchbond 1, Heliobond and F-2000) was tested against an established cell line, L929. Under aseptic conditions 3, 5 and 10 microL dentin bonding agents were placed in the centre of Petri dishes. Each dish was covered with a 5-mL suspension of fibroblasts at a concentration of 40 000 cells mL(-1). The cultures were incubated at 37 degrees C and cytotoxicity was assessed by a quantitative technique at 24 and 72 h. All the dentin bonding agents were found to be cytotoxic. Scotchbond 1 and F-2000 showed the highest cytotoxicity followed by Solobond and Bond 1. Heliobond and Syntac were the least toxic materials.

Abstract: The cytotoxic effects of neutral and alkaline EDTA solutions were evaluated and compared with those of sodium hypochlorite solution using an established cell line: L929. Cytotoxicity was assessed by a quantitative technique at five observation periods (1, 3, 6, 12, and 24 h). All tested agents showed moderate to severe cytotoxicity in the present experimental model in a concentration-dependent manner.

Abstract: In endodontic practice, calcium hydroxide is widely used for a number of reasons associated with its high pH. The purpose of the present study was to determine in vitro the alkalizing potential of newly introduced calcium hydroxide gutta-percha points that are proposed for temporary filling of root canals. The materials tested were: calcium hydroxide gutta-percha points; chemical pure calcium hydroxide powder mixed with distilled water; and Reogan rapid, a nonsetting calcium hydroxide preparation. The materials were placed into dialysis tubing and transferred into plastic vials containing bidistilled water. Measurements were taken by a digital pH meter after 10, 20, and 30 s; 1, 15, and 30 min; and 1, 2, 3, 24, 48, 72, 96, and 120 h. The calcium hydroxide containing gutta-percha points showed a significantly lower alkalizing potential than Reogan rapid and calcium hydroxide mixed with distilled water (p < 0.05).

Abstract: The cytotoxicity of three resin-based root canal sealers (AH26, AH-Plus, Topseal) was evaluated in vitro. The experiments included two cell lines, L929 mouse skin fibroblasts and RPC-C2A rat pulp cells. The cytotoxicity was assessed by sulforodamine B (SRB) colorimetric assay and hemocytometer viable cell counting after 24- and 48-h exposure. AH26 had a severe cytotoxic effect whilst Topseal and AH-Plus showed a markedly lower toxic influence on the cells during the experimental period.

Abstract: Cell cultures of L929 and BHK21/C13 cells were used to evaluate the toxicity of a newly introduced bleaching agent (Colgate Platinum) compared to hydrogen peroxide, an established bleaching agent. The cell reaction was determined by a quantitative technique at 24 h and 72 h. Both bleaching materials had a dose-dependent effect on cell viability. Concentrations of hydrogen peroxide causing a 50% decrease in cell number (50% inhibition dose-ID50) were calculated as 0.00034% after 24 h and 0.00001% after 72 h in L929 cells. The ID50 of hydrogen peroxide was found to be 0.00016% after 24 h and 0.00007% after 72 h in BHK21/C13 cells. The ID50 of Colgate Platinum was 0.00074% after 24 h and 0.00045% after 72 h in L929 cells and 0.00055% after 24 h and 0.00024% after 72 h in BHK21/C13 cells. The results showed that, in vitro, both bleaching agents were cytotoxic to fibroblasts and the new bleaching agent was less toxic than hydrogen peroxide.

Abstract: The role of intracanal medication in root canal treatment is very important. Calcium hydroxide (Ca(OH)2) is considered to fulfill many of the properties of an ideal root canal dressing mainly due to its alkalizing pH. It is bacteriocidal and neutralizing to the remaining tissue debris in the root canal(s) and through the continuous release of OH- ions it promotes an alkalizing osteogenic environment for the surrounding tissues. The purpose of this study was to examine the pH values of various Ca(OH)2 based on compounds used as intracanal medicaments over a period of 5 days. The following materials were tested: Calasept, Calcicur, Calxyl blue, Calxyl red, Reogan rapid, and Tempcanal. After a fast OH- release period (2 h) each compound reached an asymptotic pH state. The results showed that all materials exhibited alkalizing pH with Reogan rapid, Calxyl Red, and Calcicur being the most potent (p = 0.05). The final pH of each compound correlated positively with the Ca(OH)2 mass fraction contained in it.

Abstract: The cytotoxicity of two glass-ionomer root canal sealers (Ketac-Endo and Endion) was tested by using an established cell line, BHK21/C13. Under aseptic conditions, the sealers were prepared according to the manufacturers' directions, and 0.1 ml of each material was placed in petri dishes. After setting for 6 h, the sealers were covered with 20 x 10(4) cells per dish. The cultures were incubated at 37 degrees C for 24 h, 48 h, and 72 h. Cytotoxicity was assessed by a quantitative technique at three observation periods. Endion was highly cytotoxic, causing a significant decrease in cell density. Ketac-Endo proved to be a very biocompatible material.

Abstract: Intracoronal bleaching of nonvital, teeth with 30% hydrogen peroxide is occasionally associated with external cervical root resorption. The exact mechanism by which bleaching induced root resorption occurs is not yet fully understood. The relationship of cementum to the enamel at the cementoenamel junction may have clinical significance. Seventeen single rooted human mandibular premolars extracted atraumatically for orthodontic reasons were used. The radicular hydrogen peroxide penetration in each tooth was measured in vitro by an indirect colorimetric method. Thereafter, the teeth were examined with a scanning electron microscope to determine the type of the cementoenamel junction. It was found that the radicular penetration of 30% hydrogen peroxide was related to the type of cementoenamel junction.

Abstract: The cytotoxicity of three calcium hydroxide-containing root canal sealers (Sealapex, CRCS and Apexit) was tested by using L929 and BHK 21/C13 cells. After setting for 24 h, the sealers were covered with cell suspension. Cytotoxicity was determined by a quantitative technique at 24 h, 48 h and 72 h. All the sealers were found to be cytotoxic. Sealapex showed the highest cytotoxicity, causing a significant decrease in cell density. CRCS was less toxic than Sealapex and more toxic than Apexit. Apexit proved to be the least toxic material.