Longitudinal evaluation of the seal of endodontic retrofillings

Retrograde root filling with EBA cement or amalgam. A comparative clinical study

This article presents a comparative clinical study of reinforced zinc oxide eugenol (EBA) cement and amalgam used as retrograde root filling materials. All patients were followed for a minimum of 3 years after surgery. Clinical and radiographic evaluation was performed. Successful healing with complete bone regeneration was noted in 57% in the reinforced zinc oxide eugenol group compared with 52% in the amalgam group. Uncertain healing with a certain degree of bone regeneration was seen in 24% in the reinforced zinc oxide eugenol group compared with 19% in the amalgam group. Unsuccessful healing with failure of bone regeneration was seen in 20% in the reinforced zinc oxide eugenol group compared with 29% in the amalgam group. Statistical analysis failed to show any significant difference in healing between the two retrograde filling materials. The results of this study indicate that retrograde root filling with reinforced zinc oxide eugenol cement has a similar prognosis as with amalgam over a 3-year period.

Longitudinal evaluation of the seal of IRM root end fillings

IRM has been recommended for root end filling during endodontic surgery. This study evaluated the seal of IRM root end fillings prepared with various powder to liquid ratios (P:L) at extended time intervals using a fluid filtration method. The P:L of IRM evaluated included 2, 3, 4, 5, and 6 g/ml and the P:L which resulted from the manufacturer's recommended scoop and dropper. Ten teeth were evaluated for microleakage for each group at 1, 2, 3, 4, 8, and 12 wk after insertion. There were no significant differences in the microleakage of any of the various P:L groups at weeks 3, 8, and 12. These results suggest that higher P:L of IRM than those previously recommended for temporary restorations and for endodontic access preparations may be acceptable for root end fillings. IRM of higher P:L has other advantages such as ease of placement and decreased setting time, toxicity, and solubility.

Dye leakage of four root end filling materials: effects of blood contamination

The purpose of this study was to compare the amount of dye leakage (in the presence versus absence of blood) in root end cavities filled with amalgam, Super EBA, IRM, and a mineral trioxide aggregate. After removing the anatomical crowns of 90 extracted human teeth, their roots were instrumented and obturated. Except for their apical 2 mm, the root surfaces were sealed with nail polish. After removal of the apical 2 to 3 mm of each root, a standardized root end cavity was prepared. Five root ends were filled with gutta-percha and no sealer, and another five root ends were filled with sticky wax. These served as positive and negative controls, respectively. The remaining 80 roots were divided into four equal groups and filled with the test materials. For each material, half of the root end cavities were dried prior to placing the filling material. The remaining half were filled after they were contaminated with blood. All 90 roots were then immediately placed in 1% methylene blue dye for 72 h. Finally, the roots were split and linear dye penetration was measured and statistically analyzed (analysis of variance). Presence or absence of blood had no significant effect on the amount of dye leakage. However, the results showed that there was a significant leakage difference between the root end filling materials (p < 0.0001). Mineral trioxide aggregate leaked significantly less than other materials tested with or without blood contamination of the root end cavities.

Apical dentin permeability and microleakage associated with root end resection and retrograde filling

This study evaluated the apical leakage associated with various depths of retrograde fillings placed in root apices which had been resected at one of three different angles. Leakage was assessed with a hydraulic conductance apparatus. Teeth were divided into groups corresponding to the angle of apical resection (0, 30, and 45 degrees to the long axis of the root) and apical leakage was determined following incremental increases in the depth of the retrograde filling (Ketac Silver). Increasing the depth of the retrograde filling significantly decreased apical leakage; there was also a significant increase in leakage as the amount of bevel increased. Both the permeability of resected apical dentin and microleakage around the retrograde filling material had a significant influence on apical leakage.

An electrochemical study of the sealing ability of different retrofilling materials

Eighty-eight extracted mandibular and maxillary cuspids were selected for this study. Eighty cuspids were used as experimental groups and eight were used as controls. Anatomical crowns were resected, root canals were prepared, and the apical 2 mm of the roots were removed. The experimental roots received apical cavity preparations and were randomly divided into four equal groups. The apical cavities were retrofilled with amalgam, heat-sealed gutta-percha, zinc polycarboxylate cement, or glass ionomer cement. Leakage was measured using an electrochemical technique. Statistical analysis of the results indicated that glass ionomer sealed significantly better than the other materials, followed by amalgam, heat-sealed gutta-percha, and zinc polycarboxylate cement, respectively.

An evaluation of the effect of methylene blue dye pH on apical leakage

The effect of varying the pH of 2% methylene blue dye on apical leakage was evaluated. Eighty-four roots of extracted human teeth were used in this study. The roots were endodontically cleaned and shaped, obturated, apically resected, and amalgam or Temporary Endodontic Restorative Material retro-fillings were placed. The roots were immersed for 7 days in dye solutions of controlled pH of 1, 2, 3, 5 or 7, or in a 2% unbuffered deionized water solution of methylene blue. The results demonstrated significantly less leakage in the pH 1 and 2 amalgam groups. All other amalgam groups and the Temporary Endodontic Restorative Material groups showed no significant differences attributable to pH. Temporary Endodontic Restorative Material retrofilling groups demonstrated statistically significantly less apical leakage at each pH evaluated than the amalgam-retrofilled groups. Additionally, a significant buffering effect of the root structure on the dye solutions was measured.

A comparative sealability study of different retrofilling materials

The purpose of this study was to compare the sealing ability of high-copper amalgam, glass ionomer cement, and silver glass ionomer cement as retrofilling materials when used with and without varnish. Seventy extracted human single-rooted anterior teeth were instrumented and the root canals obturated with laterally condensed gutta-percha and sealer. The apical 3 mm of each root was resected and a 2 mm-deep apical Class I preparation cut. The roots were then randomly allocated to six groups of 10 teeth and retrofilled with one of the experiment materials. Group I comprised high-copper amalgam; group 2, high-copper amalgam with cavity varnish; group 3, glass ionomer cement without varnish; group 4, glass ionomer cement with varnish; group 5, silver glass ionomer cement without varnish; and group 6, silver glass ionomer cement with varnish. Two groups of five roots each were used as positive and negative controls. The root surfaces were coated with nail polish and specimens immersed in 2% methylene blue solution for 14 days. After vertical sectioning, dye penetration was examined under a stereomicroscope. The results of the study were analysed statistically. The sealing ability of the conventional glass ionomer cement with varnish was significantly better while dye penetration was higher in silver glass ionomer cement without varnish group than the other groups (P < 0.01).

Sealing ability of cermet ionomer cement as a retrograde filling material

An in vitro dye leakage study was performed to compare the sealing ability of high copper amalgam with cavity varnish and cermet ionomer cement with and without varnish when used as retrofilling materials. The root canals of 54 maxillary anterior teeth were instrumented and obturated with gutta-percha and sealer. The apical 3 mm of the roots were resected and apical class I cavity preparations were made. The roots were then randomly divided into three groups and retrofilled with one of the experimental materials. After 72 h of immersion in India ink, the roots were cleared and evaluated for leakage with a stereomicroscope. Statistical analysis indicated that the cermet ionomer cement with varnish group had significantly less leakage than the amalgam group (P < 0.0014) and the cermet ionomer cement without varnish group (P < 0.001). There was no significant difference between the other two groups (P > 0.05).

The adaptation and sealing ability of light-cured glass ionomer retrograde root fillings

The adaptation and sealing ability of a light-cured glass ionomer cement when used as a retrograde root filling was assessed using a confocal optical microscope with and without a fluorescent dye. This material was compared with a conventional glass ionomer cement and amalgam. The root canals of 60 extracted human single-rooted teeth were prepared and filled with gutta-percha and sealer. All the teeth were apicected, retrograde cavities were prepared, and then divided into three groups of 20 teeth each and filled with the test materials. The light-cured glass ionomer cement was well adapted to the retrograde cavity and apicected root surface. Within the retrograde cavity the cement was often well adapted to one wall, but gaps were found on the opposite cavity wall. This was probably caused by the polymerization contraction of the material. In contrast, the amalgam retrograde root fillings were poorly adapted to the cavities, with gaps between the cavity walls and amalgam. This group exhibited the poorest sealing ability as measured by the extent of dye penetration. The conventional glass ionomer cement was often found smeared over the root face, and there were unfilled voids at the base of some retrograde cavities. The results of the dye leakage study were analysed statistically. The sealing ability of the light-cured glass ionomer cement was significantly better than that of amalgam (P less than 0.001). The dye penetration around the light-cured glass ionomer cement and the conventional glass ionomer cement was not significantly different (P greater than 0.05). However, the sealing ability of the conventional glass ionomer cement was significantly better than that of amalgam (P less than 0.05).

A 24-week study of the microleakage of four retrofilling materials using a fluid filtration method

The microleakage after retrofillings of amalgam, amalgam with cavity varnish, silver-containing glass ionomer cement, and intermediate restorative material was compared in vitro. Thirty-six extracted human incisors and canines were instrumented, obturated with gutta-percha without sealer, subjected to apicoectomy, and retrofilled with the materials described above. After removal of the gutta-percha filling, the microleakage from both directions (apically and coronally) was measured quantitatively and longitudinally for 24 wk after filling by a fluid filtration technique. All four retrofilling materials revealed some apical and coronal leakage at all time periods. The amalgam group showed statistically significant (p less than 0.001) apical leakage at 1.5 h. The use of cavity varnish significantly reduced the apical leakage of the amalgam group at 1.5 h. The silver-containing glass ionomer cement and intermediate restorative material groups showed significantly (p less than 0.05) less coronal leakage compared with the amalgam group at 1.5 h. Scanning electron microscopy of selected samples showed marginal defects of approximately 5 microns between the root dentin and the retrofilling material.

Silver glass ionomer cement as a retrograde filling material: a study in vitro

Comparison was made of the apical microleakage of retrograde fillings with amalgam and with silver glass ionomer cements using a modified dye penetration method. Forty instrumented human teeth were divided into four groups. Each group was characterized by a different retrograde filling material or technique: Group 1--silver glass ionomer (SGI); group 2--SGI with previous acid wash of the cavity; group 3--SGI in a previously acid washed cavity, protected with varnish; and group 4--zinc-free amalgam. A paper cone for dye adsorption analysis was placed in contact with retrofill and the main canal was obturated with thermoplasticized gutta-percha. All teeth were coated, immersed in methylene blue dye, and evacuated to assure complete penetration of the dye in any possible void. Later the teeth were cleared and evaluated under stereomicroscope. Statistical analysis showed that group 1 had the least microleakage of all. In addition, the biocompatibility of the SGI and varnish was compared with that of amalgam using the 51Cr release evaluation method. The results showed that SGI and varnish were less cytotoxic than amalgam. It was concluded that SGI cement can be considered an alternative retrograde filling material.