Ayce Unverdi Eldeniz

Effect of Various Endodontic Irrigants on the Push-out Bond Strength of Biodentine and Conventional Root Perforation Repair Materials

INTRODUCTION The aim of this study was to evaluate the effect of various endodontic irrigants on the push-out bond strength of Biodentine (Septodont, Saint Maur des Fossés, France) in comparison with contemporary root perforation repair materials. METHODS Midroot dentin of canine teeth was horizontally sectioned into 1-mm-thick slices. The canal space of each dentin slice was enlarged with a diamond bur to 1.4 mm in diameter. The samples were divided into 5 groups (n = 40), and the following materials were placed, respectively: Biodentine, ProRoot MTA (Dentsply Tulsa Dental, Tulsa, OK), amalgam, Dyract AP (Dentsply DeTrey, Konstanz, Germany), and intermediate restorative material (IRM, Dentsply DeTrey). The samples were wrapped in wet gauze for 10 minutes and divided into 3 subgroups (n = 10) to be immersed into 3.5% sodium hypochlorite, 2% chlorhexidine gluconate (CHX), or saline for 30 minutes. No irrigation was performed in the controls (n = 10), and a wet cotton pellet was placed over each test material. After incubation for 48 hours, the dislodgement resistance of the samples was measured using a universal testing machine. The samples were examined under a stereomicroscope to determine the nature of the bond failures. RESULTS Biodentine showed significantly higher push-out bond strength than MTA (P < .05). The statistical ranking of push-out bond strength values was as follows: Dyract AP > amalgam ≥ IRM ≥ Biodentine > MTA. The push-out bond strength of Dyract AP, amalgam, IRM, and Biodentine was not significantly different when immersed in NaOCl, CHX, and saline solutions, whereas MTA lost strength when exposed to CHX. CONCLUSIONS Biodentine showed considerable performance as a perforation repair material even after being exposed to various endodontic irrigants, whereas MTA had the lowest push-out bond strength to root dentin.

A laboratory assessment of coronal bacterial leakage in root canals filled with new and conventional sealers

AIM To evaluate the resistance to ex vivo bacterial leakage over a 40-day period of root canal fillings with five new root canal sealers: RC Sealer, Epiphany, EndoREZ, GuttaFlow and Acroseal, compared with Apexit, AH Plus and RoekoSeal. METHODOLOGY One hundred and forty-four single rooted human teeth were divided randomly into eight test (n = 15) and two control groups (n = 12). The root canals were filled using a single cone technique with gutta-percha except in the Epiphany and EndoREZ groups. These were filled with Resilon and resin-coated gutta-percha, respectively. The gutta-percha surface of the GuttaFlow group was coated with an experimental primer prior to filling. Positive controls were filled with gutta-percha without sealer and tested with bacteria, whereas negative controls were sealed with wax to test the seal between the chambers. Filled roots were incorporated in a split chamber model system using Streptococcus mutans as a microbial marker. Leakage was assessed for turbidity of the broth in the lower chamber every day for 40 days. Survival analysis was performed using the Kaplan-Meier product limit method and event times were compared using the Log-rank test (alpha = 0.05). RESULTS Epiphany, GuttaFlow with test primer and Apexit prevented leakage significantly better than AH Plus, RC Sealer, RoekoSeal, EndoREZ and Acroseal (P < 0.05). None of the specimens in the AH Plus, RC Sealer, RoekoSeal and EndoREZ groups resisted bacterial penetration for 40 days. CONCLUSION The new sealers, Epiphany and GuttaFlow with primer, along with Apexit, showed better resistance to bacterial penetration than the other new or traditional sealers tested.

Effects of different curing units and luting agents on push-out bond strength of translucent posts.

INTRODUCTION The aim of this study was to evaluate the effects of different curing units and 2 luting cements on the push-out bond strength of a translucent fiber post. METHODS Thirty maxillary incisor roots were endodontically treated. Post spaces were prepared, and the smear layers were removed. Posts (FRC Postec Plus) were luted with either a self-etch cement (Panavia F 2.0) or a self-adhesive cement (Maxcem). Luting agents were then light-activated with a quartz-tungsten-halogen, a blue light-emitting diode, or a plasma-arc curing unit. Roots/cemented posts were transversally sectioned from coronal to apical. Push-out tests were performed, and data were analyzed by using three-way analysis of variance and Tukey tests. RESULTS Push-out bond strengths were significantly affected by the type of luting agent (P < .05) and root region (P < .05). The type of light source used in curing did not affect push-out bond strengths (P > .05). CONCLUSIONS Self-adhesive resin cement provided higher bond strength than the self-etch cement when smear layer was removed before the post cementation. The push-out bond strength in the apical portion of the root was significantly lower than in the coronal region. The use of different curing units in the photoirradiation of dual-cured resin cement did not affect the retention of the fiber post as a result of the limited light transmission capability of this post.

Effect of Solvents on Bonding to Root Canal Dentin

The long-term success of resin cementation of post/cores is likely increased with improvement in resin-root canal dentin bonding. The adverse effect of some irrigation constituents (NaOCl, H2O2) or medications (eugenol) on the bond strengths of resins to dentin have been reported. The purpose of this in vitro study was to evaluate the effect of two gutta-percha solvents (chloroform versus halothane) on microtensile bond strength to root canal dentin. Thirty, extracted, human, single-rooted teeth were instrumented to a #70 file and randomly divided into 3 groups of 10 each. The root canals were treated with water, chloroform, or halothane for 60 s. All root canals were obturated using C&B Metabond. After 24 h of storage in distilled water, serial 1-mm-thick cross-sections were cut and trimmed. Microtensile bond strength to apical, middle, and coronal root canal dentin were measured using an Instron machine. Using pooled data, the results indicated that water-treated roots had significantly higher resin-dentin bond strengths compared with chloroform or halothane treatment groups (control: 23.9 MPa; chloroform: 18.3 MPa; halothane: 17 MPa; p < 0.05). Gutta-percha solvents have an adverse effect on bond strengths of adhesive cements to root canal dentin.

Accuracy of two electronic apex locators in primary teeth with and without apical resorption: a laboratory study

AIM To evaluate the accuracy of the Root ZX (J Morita Corp., Kyoto, Japan) and Tri Auto ZX (J Morita Corp.) devices for measuring root canal length in primary teeth with and without apical resorption. METHODOLOGY Thirty-four extracted human primary molar teeth with resorption and 19 primary teeth without resorption were collected. After endodontic access preparation, the actual lengths of the teeth were determined. The teeth were then embedded in an alginate model to determine the electronic working length measurement. Statistical evaluation was completed using Students t-tests. RESULTS For the Root ZX, there was no significant difference between those teeth with root resorption and those without. However, for the Tri Auto ZX, there was a significant difference in the electronic measurements between those teeth with root resorption and those without (P < 0.05). Significant differences were found amongst the measurements of the two apex locators (P < 0.05). For root canals with resorption, the respective accuracy rates (within +/-0.5 mm) of Root ZX and Tri Auto ZX were 83.33% and 89.47%; within +/-1 mm, the Root ZX and Tri Auto ZX demonstrated 98.95% and 100% accuracy, respectively. For root canals with no resorption, the percentage of measurements within +/-0.5 mm of the apical construction was 89.28% for the Root ZX and 80.35% for the Tri Auto ZX. The accuracy within +/-1 mm of the Root ZX and the Tri Auto ZX was 98.22% and 100%, respectively. CONCLUSION Within the limitations of this laboratory study, the presence of resorption affected the performance of the Tri Auto ZX more than the Root ZX.

A comparative evaluation of sealing ability of a new, self-etching, dual-curable sealer: Hybrid Root SEAL (MetaSEAL)

OBJECTIVE To assess the long-term sealing ability of a new dual-curable, self-etching, 4-META containing resin-based sealer: Hybrid Root SEAL (MetaSEAL in the United States) and compare with RealSeal and AH Plus sealers. METHODOLOGY Root canals of 44 extracted and decoronated single-rooted human teeth were instrumented using a crown-down technique with ProFile 0.04 tapered NiTi rotary instruments to ISO size 30 and then to size 45 with K-hand files. Four roots were selected and used as positive and negative controls (n = 2), the rest were randomly divided into 4 groups (n = 10) and filled using 0.04 tapered size 45 cones as follows: Group 1: AH Plus with gutta-percha; Group 2: Hybrid Root SEAL (MetaSEAL) with gutta-percha; Group 3: Hybrid Root SEAL (MetaSEAL) with Resilon point; and Group 4: RealSeal with Resilon point. The quality of seal of each specimen was measured after 1, 4, 12, and 24 weeks using a fluid transport model. Measurements were made at 2-minute intervals for 8 minutes. The data were calculated as Lp and statistically analyzed using 2-way repeated measures of ANOVA and Bonferroni pairwise comparison tests (alpha = 0.05). RESULTS There were no significant differences among test materials in terms of fluid microleakage values (P = .126). There were statistically significant differences among the time periods (P = .009) and observed between 1- and 24-week test periods. There was significant interaction between root canal filling materials and time of testing (P = .048). CONCLUSION Within the limitations of this in vitro study, it was concluded that recently introduced Hybrid Root SEAL (MetaSEAL) showed similar sealing performance with RealSeal and AH Plus sealers when used either with gutta-percha or Resilon at 24 weeks.

Thermal Changes in the Pulp Chamber during Different Adhesive Clean-up Procedures

The aim of this in vitro study was to measure the temperature changes in the pulpal chamber when different adhesive clean-up procedures were used. Ninety intact extracted human maxillary central incisors were used in the study. The teeth were divided into six groups of 15 teeth each. The removal of the remaining composite on the tooth surface was performed with a tungsten carbide bur. The residual adhesive was removed using a high-speed handpiece with and without water cooling and a contra-angle handpiece with and without water cooling at high and low speeds. A J-type thermocouple wire was positioned in the center of the pulp chamber. The results were analyzed with analysis of variance (ANOVA) and the Tukey-honestly significant difference test. Two-factor ANOVA revealed significant interaction between the handpiece type and water cooling. In this study, the high-speed contra-angle handpiece without water cooling group had the highest deltaT values (7.58 degrees C+/-1.84 degrees C) among all the clean-up procedures. The decrease in pulpal temperature with water cooling was -5.34 degrees C for the handpiece, -5.36 degrees C for the low-speed contra-angle handpiece and -4.98 degrees C for the high-speed contra-angle handpiece. Clinicians should be aware of the potential thermal damage to the pulp, which may result from long clean-up procedures without water cooling. Adhesive removal procedures should be performed with adequate water cooling to prevent temperature increases that might be harmful to pulpal tissues.

Effect of Gutta-percha Solvents on Mineral Contents of Human Root Dentin Using ICP-AES Technique

The purpose of this in vitro study was to evaluate the mineral contents of root-canal dentin before and after treatment with two commonly used gutta-percha solvents: chloroform and halothane. Twenty extracted human premolars, whose crowns and apical thirds had been removed, were used. Pulp tissues were removed and the teeth were randomly divided into two groups including 10 teeth each. Root canals were enlarged with Gates Glidden burs (#1, 2, and 3). Dentin chips were obtained and saved in plates to serve as a control. Root-canal-dentin walls were then treated with chloroform or halothane for 15 min. Dentin chips were again obtained using Gates Glidden burs (#4, 5, and 6). The levels of five elements, calcium, phosphorus, magnesium, potassium, and sulfur, in each specimen were analyzed using ICP-AES (inductively coupled plasma atomic emission spectrometry) technique. Changes in the levels of the chemical elements were recorded. Differences between the groups were statistically analyzed using Mann-Whitney U test. There was a significant decrease in Ca level and significant increase in Mg level after treatment with halothane (p < 0.05). There was a significant increase in Mg level after treatment with chloroform. The changes in other elements levels after treatment with gutta-percha solvents were minimal and statistically not significant (p > 0.05). As a result it was concluded that gutta-percha solvents have effect on mineral contents of root dentin.

Shear Bond Strength of Four Resin Cements Used to Lute Ceramic Core Material to Human Dentin

PURPOSE This study evaluated the effect of four resin cements on the shear bond strength of a ceramic core material to dentin. MATERIALS AND METHODS One hundred twenty molar teeth were embedded in a self-curing acrylic resin. The occlusal third of the crowns were sectioned under water cooling. All specimens were randomly divided into four groups of 30 teeth each according to the resin cement used. One hundred twenty cylindrical-shaped, 2.7-mm wide, 3-mm high ceramic core materials were heat-pressed. The core cylinders were then luted with one of the four resin systems to dentin (Super-Bond C&B, Chemiace II, Variolink II, and Panavia F). Half of the specimens (n = 15) were tested after 24 hours; the other half (n = 15) were stored in distilled water at 37 degrees C for 1 day and then thermocycled 1000 times between 5 degrees C and 55 degrees C prior to testing. Shear bond strength of each specimen was measured using a universal testing machine at a crosshead speed of 1 mm/min. The bond strength values were calculated in MPa, and the results were statistically analyzed using a two-way analysis of variance (ANOVA) and Tukey HSD tests. RESULTS The shear bond strength varied significantly depending on the resin cement used (p < 0.05). The differences in the bond strengths after thermocycling were not remarkable as compared with the corresponding prethermal cycling groups (p > 0.05). Significant interactions were present between resin cement and thermocycling (p < 0.05). After 24 hours, the specimens luted with Variolink II (5.3 +/- 2.2 MPa) showed the highest shear bond strength, whereas the specimens luted with Chemiace II (1.6 +/- 0.4 MPa) showed the lowest. After thermocycling, the bond strength values of specimens luted with Chemiace II (1.1 +/- 0.1 MPa) and Super-Bond C&B (1.7 +/- 0.4 MPa) decreased; however, this was not statistically significant (p > 0.05). The increase in the shear bond strength values in the Panavia F (4.5 +/- 0.7 MPa) and Variolink II (5.5 +/- 2.1 MPa) groups after thermocycling was also not statistically significant (p > 0.05). CONCLUSION Variolink II and Panavia F systems showed higher shear bond strength values than Chemiace II and Super-Bond C&B. They can be recommended for luting ceramic cores to dentin surfaces.

Bacterial killing by several root filling materials and methods in an ex vivo infected root canal model.

AIM To evaluate the ability of two root canal sealers (Epoxy resin-based AH Plus or polydimethylsiloxane-based GuttaFlow) and five root filling techniques (continuous wave of condensation, Thermafil, lateral condensation, matched taper single gutta-percha point, laterally condensed-matched taper gutta-percha point) to kill bacteria in experimentally infected dentinal tubules. METHODOLOGY An infected dentine block model was used. One hundred and twenty extracted, single-rooted human teeth were randomly divided into 10 test (n = 10) and 2 control (n = 10) groups. The roots, except negative controls, were infected with Enterococcus faecalis for 21 days. The root canals were then filled using the test materials and methods. Positive controls were not filled. Sterile roots were used as negative controls. Dentine powder was obtained from all root canals using gates glidden drills using a standard method. The dentine powder was diluted and inoculated into bacterial growth media. Total colony-forming units (CFU) were calculated for each sample. Statistical analysis was performed using the Kruskal-Wallis and Mann-Whitney U test. RESULTS The epoxy resin-based sealer was effective in killing E. faecalis except when using Thermafil (P < 0.05), but the polydimethylsiloxane-based sealer was not effective in killing this microorganism except in the continuous wave group (P < 0.05). CONCLUSIONS In the test model, AH Plus killed bacteria in infected dentine more effectively than GuttaFlow. The filling method was less important than the sealer material.