An investigation on the antibacterial and antibiofilm efficacy of cationic nanoparticulates for root canal disinfection.

Aim To assess ex vivo the cytotoxic effects of five new root canal sealers (RC Sealer, Epiphany, EndoREZ, GuttaFlow and Acroseal) and three existing products (AH Plus, RoekoSeal and Apexit) using primary human gingival fibroblasts (HGF) and a mouse fibroblast cell line, L929.



Methodology  Eight samples of each sealer were fabricated in sterile cylindrical Teflon blocks, 4.4 mm diameter and 2 mm height and then divided into two groups, fresh and aged specimens. Extraction of fresh specimens was carried out after setting whilst aged specimens were placed in Petri dishes and kept in a humid chamber at 37 °C for 7 days before extraction in cell culture medium using the ratio 1.25 cm2 mL−1. Undiluted eluates were used for the dimethylthiazol diphenyltetrazolium bromide (MTT) assay with HGF and L-929. Morphology of HGF cells was also examined by an inverted microscope using undiluted eluates of the sealers. The results were analysed using a two-tailed t-test (α = 0.05) between groups.



Results  Resin-based (Epiphany and EndoREZ) and calcium hydroxide-based (Apexit and Acroseal) sealers were significantly more cytotoxic than other sealers (P < 0.05). However, L929 cells were more sensitive to Apexit and EndoREZ than HGF cells. RC Sealer showed mild cytotoxicity to HGF at both setting times. AH Plus did not exert any cytotoxic effect to HGF and aged specimens appeared to induce cellular proliferation. RoekoSeal and GuttaFlow also demonstrated mild cytotoxicity. GuttaFlow was slightly more cytotoxic to both cultures, especially when tested fresh.



Conclusions  Toxicity varied but RC Sealer and GuttaFlow were the least toxic new sealers.

Cytotoxicity of new resin-, calcium hydroxide- and silicone-based root canal sealers on fibroblasts derived from human gingiva and L929 cell lines.

AIM: This in vitro study evaluated the microleakage of root fillings involving four root-canal sealers including AH Plus (De-Trey, Switzerland), RoekoSeal (Roeko, Germany). Ketac-Endo (ESPE, (Germany) and Sultan (Sultan Chemists, USA. METHODOLOGY: Forty extracted human maxillary anterior teeth were used. The coronal part of each tooth was removed and the root canals were prepared using the step-back technique and apical enlargement to size 60 file. The specimens were randomly divided into four groups of 10 samples, filled with one of the test materials and gutta-percha cones by the cold lateral condensation technique. A fluid filtration method was used for quantitative evaluation of apical leakage. The leakage was measured by the movement of an air bubble in a capillary glass tube connected to the experimental root section. Measurements of fluid movement were made at 2-min intervals for 8 min. Water transport through existing voids in the obturated canals could be measured reproducibly in this way. The quality of the seal of each specimen was measured after 7,14 and 21 days. RESULTS: Statistical analysis indicated that all the root fillings showed less leakage after 21 days (P < 0.05). Fillings incorporating Sultan showed significantly more leakage than all other sealers. CONCLUSIONS: Root fillings with RoekoSeal in combination with cold lateral condensation technique showed better sealing than those with Ketac-Endo, AH Plus and Sultan sealers after 21 days. The fluid filtration test used in this study gave quantitative results and allowed nondestructive long-term evaluation of specimens.

A quantitative evaluation of apical leakage of four root-canal sealers.

The purpose of this study was to evaluate the apical sealing ability and adaptation to dentine of two resin-based root canal sealers. The root canals of 55 human maxillary anterior teeth were prepared using a step-back technique and the smear layer removed with 17% ethylenediaminetetraacetic acid. The teeth were divided into two groups of 25 teeth and the remaining five teeth served as control. Then the teeth were prepared and obturated with gutta-percha by a lateral condensation and either AH plus and EndoRez used as a sealer. Twenty teeth from each group were used for the apical leakage test and the remaining five teeth from each group were used for examination under the scanning electron microscope (SEM). For apical leakage test, teeth were covered with nail varnish and sticky wax to within 1 mm of the apical foramen and placed in 2% methylene blue for 7 days. After this period, the teeth were sectioned longitudinally and apical leakage measurements made. The mean value of dye penetration for AH plus was 2.87 +/- 0.43 mm, while that of EndoRez was 4.54 +/- 0.36 mm. The difference between mean of dye penetration was statistically significant (P < 0.01). The SEM examination showed both sealers had better adaptation and penetration in coronal and middle thirds than apical third of root canal. In apical third, AH plus was adapted better adpated to dentine than EndoRez. In conclusion, AH plus sealer has better apical sealing ability and adaptation to dentine than EndoRez sealer.

Evaluation of apical sealing ability and adaptation to dentine of two resin-based sealers.

Endodontic sealers for non-surgical root canal treatment (NSRCT) span many compositions and attributes. This comprehensive review discusses current types of endodontic sealers by their setting reaction type, composition, and properties: zinc oxide-eugenol, salicylate, fatty acid, glass ionomer, silicone, epoxy resin, tricalcium silicate, and methacrylate resin sealers. Setting time, solubility, sealing ability, antimicrobial, biocompatibility, and cytotoxicity are all aspects key to the performance of endodontic sealers. Because sealing ability is so important to successful outcomes, the relative degree of microleakage among all the relevant sealers was calculated by way of a meta-analysis of relevant literature. Compared to AH Plus, tricalcium silicate sealers show the lowest relative microleakage among the sealers assessed, followed by silicone sealers and other non-AH Plus epoxy resin sealers. Tricalcium silicate sealers also exhibit the most favorable antimicrobial effect and excellent biocompatibility. Future sealers developed should ideally combine a hermetic seal with therapeutic effects.

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Comprehensive review of current endodontic sealers.

De Almeida WA, Leonardo MR, Tanomaru Filho M, Silva LAB. Evaluation of apical sealing of three endodontic sealers. International Endodontic Journal, 33, 25–27, 2000.



Aim  The apical sealing ability of three different endodontic sealers was evaluated in extracted teeth using dye penetration.



Methodology The root canals of 99 extracted human maxillary central incisors were prepared sequentially 2mm beyond the apical foramen with a size 55 Nitiflex file. The teeth were divided into three experimental groups and obturated by lateral condensation of cold gutta-percha and one of the following sealers: group 1, zinc oxide and eugenol sealer (Fill Canal); group 2, glass ionomer sealer (Ketac-Endo) and group 3, epoxy resin sealer (AH Plus). The teeth were covered with nail varnish to within 1mm of the apical foramen and immersed in 2% methylene blue in a



reduced pressure environment for 24h. After this period, the teeth were washed and cut longitudinally for apical leakage analysis. The values were obtained from the maximum depth of leakage as well as the average between the maximum and minimum values observed for each group.



Results  Statistical evaluation of the results showed no significant difference in the leakage between Fill Canal and Ketac-Endo (P >0.05). Leakage with AH Plus was significantly less (P <0.01) than with the other sealers.



Conclusions  All three sealers allowed some leakage to occur. Leakage with AH Plus was significantly different than with Fill Canal or Ketac-Endo.

Evaluation of apical sealing of three endodontic sealers.

This study evaluated the effects of acute exposure of Aedes aegypti third instar (L3 ) larvae to the saline extract of Opuntia ficus-indica cladodes on the biological cycle and fertility of the emerging adults. For this, larvae were treated for 24 h with the extract at ¼ LC50 (lethal concentration to kill 50% of larvae), ½ LC50 or LC50 ; the development and reproduction of the emerged adults were evaluated after a recovery period of 9 days. The resistance of proteins in the extract to hydrolysis by L3 digestive enzymes and histomorphological alterations in the larval midgut were also investigated. The extract contained lectin, flavonoids, cinnamic derivatives, terpenes, steroids, and reducing sugars. It showed a LC50 of 3.71% for 48 h. The data indicated mean survival times similar in control and extract treatments. It was observed development delay in extract-treated groups, with a lower number of adults than in control. However, the females that emerged laid similar number of eggs in control and treatments. Histological evaluation revealed absence of bacterial and fungal microorganisms in the food content in midguts from larvae treated with cladode extract. Electrophoresis revealed that three polypeptides in the extract resisted to hydrolysis by L3 digestive proteases for 90 min. The lectin activity was not altered even after 24-h incubation with the enzymes. In conclusion, the extract from O. ficus-indica can delay the development of Ae. aegypti larvae, which may be linked to induction of an axenic environment at larval midgut and permanence of lectin activity even after proteolysis.

W. A. De Almeida

Papers

Evaluation of apical sealing of three endodontic sealers.

Extract from Opuntia ficus-indica cladode delays the Aedes aegypti larval development by inducing an axenic midgut environment.