Biomedical subjects

S Calt

Publications and source records attributed to S Calt.

4 recordsLinked to original sources

PubMed2001

Comparison of the cytotoxic effects and smear layer removing capacity of oxidative potential water, NaOCl and EDTA.

UNLABELLED: This study compared the smear layer removing capability and cytotoxicity of NaOCl, EDTA and Oxidative Potential Water (OPW). Fifteen extracted single-rooted human upper incisors were examined in three groups. The root canals were enlarged to the apical foramen with K files to size #60 and irrigated with: (a) NaOCl followed by OPW, (b) OPW during and after instrumentation and (c) NaOCl followed by EDTA and NaOCl. The effect of these irrigants on the smear layer was evaluated using a scanning electron microscope. In vitro cytotoxicity of these irrigants was examined by MTT colorimetric assay. We found that the combination of NaOCl and OPW as well as the application of OPW alone, failed to remove the smear layer from the apical third, whereas the EDTA and NaOCl combination achieved complete removal. OPW, when used during and after instrumentation, removed the smear layer in the middle third more effectively than NaOCl followed by OPW. EDTA exerted more cytotoxic effects at all concentrations tested when compared with OPW and NaOCl. IN CONCLUSION: (a) OPW was less cytotoxic than other irrigants but did not effectively remove the smear layer, (b) treatment with EDTA followed by NaOCl efficiently removed of the smear layer, but their cytotoxicity should be considered during endodontic therapy.

Animals↗

PubMed2000

Smear layer removal by EGTA.

The purpose of this study was to compare the effects of ethylene glycol-bis (beta-aminoethyl ether)-N,N,N', N'-tetraacetic acid (EGTA) and EDTA on removal of the smear layer by using scanning electron microscopy. Fifteen single-rooted teeth were instrumented to size 60. Three teeth served as the control group, and the remaining teeth were assigned into two groups. After instrumentation, root canals of the first group were irrigated with 10 ml of 17% EDTA, and the second group was irrigated with 10 ml of 17% EGTA for 2 min. Both were then irrigated with 10 ml of 5% NaOCl. The teeth in the control group were irrigated with only 10 ml of 5% NaOCl. Then the specimens were sectioned longitudinally and processed for scanning electron microscopy. The results showed that the smear layer was completely removed by EDTA, but it caused erosion of the tubuli. EGTA was somewhat effective in removing the smear layer without inducing erosion. Our results suggest that EGTA is an alternative chelator for removing the smear layer.

Chelating Agents↗

PubMed1999

pH changes and calcium ion diffusion from calcium hydroxide dressing materials through root dentin.

The purpose of this study was to evaluate Ca2+ and OH- diffusion properties through root dentin by using different calcium hydroxide (CH) dressing materials. Twenty-eight single-rooted teeth were instrumented and external defects were created on the root surface. 17% EDTA was used to eliminate the smear layer. All surfaces except the external defects were sealed, and the teeth were placed in normal saline. Ca2+ concentrations and the pH in the saline were determined for 3 days as the control period. After removing the teeth from normal saline, they were filled with: (i) DT Temporary Dressing CH; (ii) CH powder and normal saline; (iii) TempCanal; and (iv) CH points. The teeth were then placed in normal saline, and Ca2+ concentrations and pH values were measured at 1, 3, 7, 14, and 28 days. Nonsetting CH pastes gradually released Ca2+, whereas this increase was absent from CH points. None of the test materials induced a pH increase in the media during the observation period. This study demonstrated that, when nonsetting CH pastes are applied to the root canal, diffusion of Ca2+ without an increase in pH to the surrounding media occurs. This implies that these type of material are more suitable than CH points for treatment of external root resorption.

Calcium Hydroxide↗

PubMed1999

Dentinal tubule penetration of root canal sealers after root canal dressing with calcium hydroxide.

The purpose of this study was to evaluate the dentinal tubule penetration of root canal sealers after root canal dressing with calcium hydroxide (Ca(OH)2). Forty-two single-rooted teeth were instrumented to size 60. Six teeth served as the control group, and the remaining teeth were assigned to two groups. Root canals of the first group were filled with the Ca(OH)2 paste; the second group was filled with TempCanal, and all were incubated for 7 days. The samples were either irrigated with only NaOCl or with EDTA, followed by NaOCl to remove Ca(OH)2. All of the teeth were obturated with CRCS, AH26, and Ketac Endo by a lateral condensation technique. The specimens were then kept at the same conditions for another 7 days, and then all of the roots were prepared for scanning electron microscopic evaluation. Scanning electron microscopic examination revealed that Ca(OH)2 was not completely removed from the root canal surfaces, and root canal sealers did not penetrate into the dentinal tubules when only NaOCl was used. EDTA followed by NaOCl irrigation resulted in complete removal of Ca(OH)2 and root canal sealers penetrated into the dentinal tubules.

Bismuth↗