Tamer Taşdemir

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.

Comparative Study of 6 Rotary Nickel-Titanium Systems and Hand Instrumentation for Root Canal Preparation in Severely Curved Root Canals of Extracted Teeth

INTRODUCTION Some improvements have been developed with new generations of nickel-titanium (NiTi) rotary instruments that led to their successful and extensive application in clinical practice. The purpose of this in vitro study was to compare the root canal preparations performed by using GT Series X and Twisted File systems produced by innovative manufacturing process with Revo-S, RaCe, Mtwo, and ProTaper Universal systems manufactured directly from conventional nitinol and with stainless steel K-Flexofile instruments. METHODS The mesiobuccal root canals of 140 maxillary first permanent molars that had between 30°-40° curvature angle and 4- to 9-mm curvature radius of the root canal were used. After root canal preparations made by using GT Series X, Twisted File, Revo-S, RaCe, Mtwo, and ProTaper Universal NiTi rotary systems and stainless steel K-Flexofile instruments, transportation occurred in the root canal, and alteration of working length (WL) was assessed by using a modified double-digital radiographic technique. The data were compared by the post hoc Tukey honestly significant difference test. RESULTS NiTi rotary systems caused less canal transportation and alteration of WL than K-Flexofile instruments (P < .05). There was no significant difference between NiTi rotary system groups at any levels (P > .05) except 2.5 mm from the WL. At this level ProTaper Universal system caused significant canal transportation (P < .05). CONCLUSIONS GT Series X and Twisted File rotary systems produced with innovative process were concluded to shape the curved canals to result in minimal canal transportation, similar to Revo-S, RaCe, Mtwo, and ProTaper Universal rotary systems manufactured by traditional methods.

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.

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.

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.

Effect of Unintentionally Extruded Mineral Trioxide Aggregate in Treatment of Tooth with Periradicular Lesion: A Case Report

INTRODUCTION This case report describes the effect of unintentionally extruded mineral trioxide aggregate (MTA) into periradicular lesions and tissues on the prognosis of periradicular healing in maxillary left central incisor with periradicular lesion. METHODS A 17-year-old girl with a large periradicular lesion from the apices of her maxillary left central to lateral incisors was referred. Tooth #9 had an open apex, but tooth #10 was normal. Conservative root canal treatment was performed to tooth #10. The apical third of the canal of tooth #9 was filled with MTA as an apical plug because of open apex. During this procedure, a radiograph was taken, and it showed an excessive extrusion of MTA into the periradicular lesion. The remaining canal space was filled with gutta-percha and AH Plus sealer by using a lateral condensation technique. RESULTS At follow-up examinations, the tooth was asymptomatic and radiographically showed repair of the lesion. Healing was achieved without any need for further endodontic surgical intervention. CONCLUSIONS The results of this case showed that complete periapical healing is possible despite the extrusion of the MTA. This might be due to biologic properties of the MTA. Even so, extrusion of the filling material is not advocated.

Cytotoxicity Analysis of Strontium Ranelate on Cultured Human Periodontal Ligament Fibroblasts: A Preliminary Report

BACKGROUND/PURPOSE The aim of this study was to analyze the cytotoxicity of strontium ranelate (SR) on human periodontal ligament fibroblasts (PDL cells) in vitro. METHODS PDL cells were obtained from healthy human third molars and cultured in Dulbeccos Modified Eagles Medium. The experimental groups were: G1, cultures treated with fresh medium (control); and G2, G3, G4 and G5: treated with SR at 20, 10, 5 and 2.5 mg/mL, respectively. The experimental times were 1, 6, 12 and 24 hours (short-term) for viability, and 2, 4, 6 and 8 days (long-term) for cell survival. The cells were counted using a hemocytometer. Data were then analyzed by one-way ANOVA and Tukeys tests (p < 0.05). RESULTS Cultures treated with the highest SR concentrations (G2 and G3) had significantly lower cell viability and cell numbers (p < 0.05) than those in G1, G4 and G5. SR at 2.5 mg/mL was non-cytotoxic to PDL cells. CONCLUSION SR was non-toxic at appropriate concentrations. Preclinical tests are needed to further assess its safety and effectiveness for tooth resorption prior to clinical use.

Treatment of horizontal root fractures using a triple antibiotic paste and mineral trioxide aggregate: A case report

This case report describes the treatment of a horizontal root fracture in a maxillary central incisor (tooth #8) using a triple antibiotic paste and mineral trioxide aggregate. A nonsurgical endodontic treatment was performed to a coronal root canal fragment of tooth #8. During the treatment procedure, 1% sodium hypochlorite solution was used for irrigation and a triple antibiotic paste was used as an intracanal medicament. The coronal part of the canal was obturated with mineral trioxide aggregate totally. At follow-up examination after 12 months, the tooth was asymptomatic and radiographically showed repair of the fracture region. Healing was achieved without any need for further interventions.