Tahsin Yildirim

Comparative study of removal of current endodontic fillings.

The aim of the present study was to assess the removability of canal fillings performed by using current methods during re-treatment with rotary instruments. Seventy-two freshly extracted human anterior teeth with single straight root canals were instrumented with Mtwo rotary files. The teeth were randomly divided into 4 obturation groups of 18 specimens each as follows: group 1, Resilon and Epiphany; group 2, GuttaFlow obturation system; group 3, EndoTwinn obturation system; group 4, gutta-percha with AH Plus sealer. The filled canals were re-treated by using Mtwo-Retreatment instruments and Mtwo instruments. The time required to remove the obturation material was recorded. After splitting the roots, the amount of residual filling material on the canal walls was imaged and measured with image analyzer software. Statistical analysis was accomplished by Kruskal-Wallis and Mann Whitney U tests for the analysis of root canal cleanliness. There was no statistically significant difference among the 4 filling techniques regarding the amount of residual material in the apical, middle, and coronal thirds and inside the whole canal area (P > .05). Regarding the mean time of re-treatment, the fillings performed by using GuttaFlow and EndoTwinn methods were removed much more quickly compared with the other 2 methods (P < .001). It was observed that the fillings performed with the above canal filling methods were removed in a similar fashion with rotary instruments during re-treatment.

Efficacy of several techniques for the removal of calcium hydroxide medicament from root canals

AIM To compare the efficacy of several techniques for the removal of calcium hydroxide (Ca(OH)(2)) from root canals. METHODOLOGY The root canals of 24 freshly extracted human mandibular premolars were prepared with ProTaper rotary instruments. The teeth were sectioned longitudinally along the length of the instrumented canals. The roots were subsequently reassembled with wires. After Ca(OH)(2) was placed into the canals, four techniques were used for its removal. In Group I, the teeth were irrigated with 5 mL of 2.5% NaOCl. Group II was treated in the same manner as Group I, but 5 mL of 17% EDTA was used in addition to NaOCl. In Group III, the teeth were irrigated with 5 mL of 2.5% NaOCl and agitated by an ultrasonic unit. In Group IV, the teeth were irrigated with 5 mL of 2.5% NaOCl and a CanalBrush was used to remove the Ca(OH)(2) . The roots were disassembled and digital photographs were taken. Measurements of residual Ca(OH)(2) were performed as percentages of the overall canal surface area. The data was analysed with one-way ANOVA with post hoc Tukey test. RESULTS Significantly less residual material was obtained with a CanalBrush and passive ultrasonic agitation of NaOCl than the other groups (P < 0.05). There was no significant difference between syringe delivery of NaOCl and NaOCl+EDTA (P > 0.05). CONCLUSIONS None of the techniques removed the Ca(OH)(2) dressing completely. CanalBrush and ultrasonic agitation of NaOCl were significantly more effective than irrigant-only techniques.

Long-term Evaluation of the Influence of Smear Layer on the Apical Sealing Ability of MTA

The aim of this in vitro study was to investigate the effect of the smear layer on apical microleakage in teeth obturated with mineral trioxide aggregate (MTA). Fifty single-rooted central maxillary teeth were used in this study. All teeth were instrumented to size 60 by using the step-back technique. The selected teeth were randomly divided into 2 groups (n = 20). In the first group (smear [+]), the teeth were irrigated with only NaOCl (5.25%). In the second group (smear [-]), the teeth were irrigated with ethylenediaminetetraacetic acid (EDTA) (17%) and NaOCl (5.25%) to remove the smear layer. The teeth were then filled with MTA. The computerized fluid filtration method was used for evaluation of apical microleakage. The quantitative apical leakage of each tooth was measured after 2, 30, and 180 days. Statistical analysis was done with the Mann-Whitney U and Wilcoxon signed ranks tests. At the end of this study there was no difference in 2 days between the groups, but removal of the smear layer caused significantly more apical microleakage than when the smear layer was left intact for 30 and 180 days (P < .005). Within the constraints of this study it can be concluded that the apical microleakage of MTA is less when the smear layer is present than when it is absent.

Evaluation of the Radiopacity of New Root Canal Paste/Sealers by Digital Radiography

The aim of the present study was to assess the radiopacity of new polydimethylsiloxane-based root canal filling paste (GuttaFlow; Coltène/Whaledent, Langenau, Germany) and resin-based root canal sealer (Adseal; Meta Biomed Co, Cheongju, Korea) and compare their radiopacity with three currently used root canal sealers (AH Plus [Dentsply DeTrey GmbH, Konstanz, Germany], Epiphany [Pentron, Wallingford, CT], and Diaket [3M ESPE AG, Seefeld, Germany]) by means of direct digital radiography. Six specimens, 5 mm in diameter and 1 mm high, were performed for each material tested. After the material set, radiographs were made by using a digital sensor and a graduated aluminum stepwedge varying in thickness from 1 to 14 mm. These samples were tested according to the international standards to compare their radiodensity to that of the aluminum stepwedge. Data were analyzed using analysis of variance and Tukey tests. The millimeters of aluminum values reported in this study were 10.41, 8.20, 6.50, 4.90, and 3.09 for AH Plus, Epiphany, Diaket, GuttaFlow, and Adseal, respectively. Although the materials evaluated had different radiopacities, all of them showed radiopacity above the minimum recommended by the International Organization for Standardization and the American National Standards/American Dental Association.

Use of mineral trioxide aggregate in the treatment of horizontal root fractures with a 5-year follow-up: report of a case.

Root fractures are those that involve dentin, cementum, and the pulp. They occur more frequently in children than adults. This case report describes the treatment and 5-year follow-up of two maxillary central incisors with horizontal root fractures using mineral trioxide aggregate and the application of intracoronal bleaching of the discolored tooth.

Effectiveness of different gutta-percha techniques when filling experimental internal resorptive cavities.

AIM To determine the quality of root fillings in teeth with artificial internal resorptive cavities filled with Thermafil, JS Quick-Fill, Soft Core, System B and Microseal, and by cold lateral compaction (LC) technique. METHODOLOGY Sixty maxillary incisor teeth were selected. After access cavity preparation and root canal instrumentation, the roots were sectioned horizontally and artificial internal resorption cavities were prepared on the canal walls. The tooth sections were cemented together and the root canals were filled using one of six different techniques: Thermafil, JS Quick-Fill, Soft Core, System B and Microseal, and by LC. The roots were then divided at the level of the previous section and each root surface was photographed. Image analysis program was used to calculate the percentage of sealer, gutta-percha and void in the internal resorptive cavities. All measurements were analysed statistically using One-way ANOVA and Newman-Keuls tests. RESULTS The Microseal technique filled 99% of the artificial resorptive area followed by LC (92%), SystemB (89%), Quick-Fill (88%), Thermafil (74%) and Soft-Core (73%). Warm gutta-percha compaction techniques filled the resorption areas with more gutta-percha than sealer (Microseal 68%, System B 62%) compared to the other techniques (LC 48%, Quick Fill 41%, Soft Core 34%, Thermafil 35%). In addition, core techniques left a considerable volume of voids in the resorptive areas (Quick-Fill 12%, Thermafil 26%, Soft Core 27%). CONCLUSIONS Warm gutta techniques filled artificial resorption cavities significantly better than the other gutta-percha techniques.

Effect of smear layer and root-end cavity thickness on apical sealing ability of MTA as a root-end filling material: a bacterial leakage study.

OBJECTIVE The aim of this study was to investigate the effect of the cavity thickness and smear layer on apical sealing ability of mineral trioxide aggregate (MTA) as a root-end filling material. STUDY DESIGN Seventy single-rooted maxillary central teeth were used in this study. All teeth were instrumented to size 50 using a step-back technique. The selected teeth were randomly divided into 4 groups, each containing 15 experimental samples and 5 positive and 5 negative control samples. In the first and second groups (smear+), the teeth were irrigated with only 5.25% NaOCl. In the third and fourth groups (smear-), the teeth were irrigated with 17% EDTA and 5.25% NaOCl to remove the smear layer. Also, in the first and third groups, cavities were prepared as 3 mm. In the second and fourth groups, cavities were prepared as 5 mm. All the root-end cavities were then filled with MTA. Nail varnish was applied to all external root surfaces to the level of the resected root-ends to prevent lateral microleakage. Samples were sterilized in an ethylene oxide sterilizer for 12 hours. The apical 3-4 mm of the roots were immersed in brain heart infusion culture medium with phenol red indicator within culture chambers. The coronal access of each specimen was inoculated every 48 hours with a suspension of Enterococcus faecalis. Bacterial leakage was monitored every 24 hours for 4 weeks. The data obtained were analyzed using a chi-squared test, with alpha = .05 as the level for statistical significance. RESULTS There were no statistically significant differences in rate of bacterial leakage among the experimental groups at 1-4 weeks (P > .05). Also, there was no difference between the groups when the 2 thickness groups were combined (P > .05). However, there was statistically significant differences when the 2 smear groups were combined for 4-week observation periods (P < .05). Removal of the smear layer caused significantly more apical microleakage than when the smear layer was left intact for 4 weeks. CONCLUSION The thickness of root-end cavity (3 or 5 mm) had no influence in the bacterial leakage of the root end filled with MTA. Removing the smear layer may not be necessary in root-end cavities filled with MTA.

Treatment of horizontal root fractures using MTA as apical plug: report of 3 cases

Root fractures are rare occurrences through all dental injuries. They comprise only 0.5% to 7.0% of traumas affecting the permanent teeth. Generally the cervical and middle thirds of the roots are affected. The healing of these lesions depends on the health of the pulp, dentine, cementum, and alveolar bone. These case reports describe the management and 2-year follow-up of 3 maxillary central incisors with horizontal root fractures treated with mineral trioxide aggregate (MTA) as apical plug.

Comparison of the sealing ability of three filling techniques in canals shaped with two different rotary systems: A bacterial leakage study

OBJECTIVE This study compared the sealing ability of 3 current filling techniques in root canals shaped with 2 different rotary systems. STUDY DESIGN Eighty human extracted mandibular premolars were divided randomly into 2 similar groups of 40 each and instrumented with either ProTaper (Dentsply Maillefer, Tulsa, OK; group A) or Mtwo (VDW; Antaeos, Munich, Germany; group B) rotary systems. Each group was divided into 3 subgroups (n = 10) and 2 control groups (n = 5). Canals were filled either with the tapered single-cone technique (SC; subgroups A1 and B1), with lateral condensation (LC; subgroups A2 and B2), or warm vertical compaction (WVC; subgroups A3 and B3). AH Plus was used as a root canal sealer in all groups. Samples were sterilized in an ethylene oxide sterilizer for 12 hours. The apical 3-4 mm of the roots were immersed in brain-heart infusion culture medium with phenol red indicator within culture chambers. The coronal access of each specimen was inoculated every 48 hours with a suspension of Enterococcus faecalis. Bacterial leakage was monitored every 24 hours for 8 weeks. The data obtained were analyzed using a chi-squared test, and P was set at .05. RESULTS In group A, 70% of the specimens filled with SC (subgroup A1), 50% of the specimens filled with LC (subgroup A2), and 20% of the specimens filled with WVC (subgroup A3) leaked. There was no statistically significant difference between the subgroups (P > .05). In group B, bacterial leakage was observed in 50% of SC samples (subgroup B1), 40% of LC samples (subgroup B2), and 50% of WVC samples (subgroup B3). There was no statistically significant difference between subgroups B1, B2, and B3 (P > .05). There was also no statistically significant difference between group A and group B (P > .05). CONCLUSION Filling with SC, LC, and WVC techniques in canals treated with ProTaper or Mtwo rotary instruments showed similar levels of sealing efficacy.

Shear Bond Strength of Conventional Glass Ionomer Cements Bound to Mineral Trioxide Aggregate

INTRODUCTION This study measured the shear bond strength of conventional glass ionomer cements (GICs; Ketac Molar Easymix and Fuji IX) bonded to white mineral trioxide aggregate (WMTA) that had been allowed to set for 2 different time intervals. METHODS Forty-eight WMTA specimens were prepared; half were stored for 45 minutes, and the remaining 24 specimens were stored for 72 hours at 37 degrees C and 100% humidity. Then each group was divided into 2 subgroups of 12 specimens, and each GIC was layered on each of the 2 WMTA preparations. The GIC-WMTA shear bond strengths were measured and were compared by using one-way analysis of variance. RESULTS The shear bond strengths with the 45-minute and 72-hour WMTAs were 8.85 and 9.16 MPa, respectively, for Ketac Molar Easymix and 9.34 and 9.96 MPa, respectively, for Fuji IX. The GIC-WMTA bond strength was not different between GIC applications to WMTA that had set for 45 minutes versus 72 hours (P >.05). CONCLUSIONS GICs might be used over MTA after the MTA has set for 45 minutes to allow single-visit procedures.