Tooth Discoloration Induced by Different Calcium Silicate-Based Cements: A Two-Year Spectrophotometric and Photographic Evaluation in Vitro.

OBJECTIVE: Calcium silicate-based cements (CSCs) may lead to coronal staining in young permanent teeth over the time. The purpose of this study was to evaluate and compare the long-term tooth discoloration induced by different CSCs. STUDY DESIGN: Ninety freshly-extracted human molars were assigned randomly into 6 groups (n=15/group) according to the CSC used as a pulpotomy material: ProRoot MTA, MTA Angelus, NeoMTA, EndoSequence Putty, Biodentine and Negative control (No cement). The color was assessed at baseline, and thereafter at 3, 6, 12 and 24 months by using both a spectrophotometer and digital images taken with and without a cross-polarizing filter. The time-dependent changes in color (ΔE) were compared within and among groups using Analysis of Variance. RESULTS: Angelus MTA and ProRooT MTA showed severe coronal discoloration (p>0.05) starting at 3 months. ΔE values of NeoMTA, EndoSequence Bioceramic Putty and Biodentine were below the perceptibility threshold, with Biodentine showing greater ΔE values than NeoMTA and EndoSequence Putty in the absence of statistical significance (p>0.05). CONCLUSIONS: Discoloration elicited by CSCs may develop soon after placement, and continue to increase for up to two years. Angelus MTA and ProRooT MTA cannot be recommended for vital pulp therapies in the esthetic zone of young individuals.

A micro-computed tomographic assessment of root canal preparation with conventional and different rotary files in primary teeth and young permanent teeth.

BACKGROUND: Root canals of primary teeth are commonly prepared with endodontic files that are originally manufactured for permanent teeth. AIM: This micro-computed tomography (micro-CT) study evaluated and compared the changes in root canal morphology after preparation with different conventional and rotary files in primary teeth and young permanent teeth. DESIGN: Seventy-two extracted primary and permanent molars were selected and randomly assigned to three subgroups according to the file systems used (n = 12/each). After pre-scanning of teeth with micro-CT, root canals were prepared with One Shape and Revo-S rotary systems and conventional endodontic files. After rescanning procedure, changes in canal volume, surface area, uninstrumented surface area, and apical transportation were evaluated. Mann-Whitney U test, Kruskal-Wallis test, and Conover's multiple comparison test were used for statistical analysis (P = .05). RESULTS: Instrumentation with rotary files resulted in significantly greater volume and surface area of root canals and less uninstrumented areas (P < .001) than with manual files (P < .001). Primary molars showed significantly less apical transportation than permanent teeth (P < .001). CONCLUSIONS: Preparation of canals with rotary files could be a viable alternative to conventional files in primary teeth. Regardless of the file system used, uninstrumented areas still exist in both primary teeth and permanent teeth.

Dentinal Tubule Penetration and Retreatability of a Calcium Silicate-based Sealer Tested in Bulk or with Different Main Core Material.

INTRODUCTION: The aim of this study was 2-fold: to evaluate the penetration of a tricalcium silicate-based endodontic sealer (EndoSequence BC Sealer; Brasseler USA, Savannah, GA) into dentinal tubules without a core material (sealer) or with .02 or .04 tapered bioceramic gutta-percha points and to compare the time required to remove the root fillings . METHODS: Roots of extracted human mandibular incisors (N = 60) were prepared with 0.04 taper nickel-titanium rotary files to #35 and randomly assigned into 3 groups (n = 10/group) according to the obturation method used: 1. obturating with sealer only, 2. sealer + .02 point, and 3. sealer + .04 point. The sealer was labeled with rhodamine B for analyzing dentinal tubule penetration under a confocal laser scanning microscope. The remaining specimens (n = 30) were used to measure the time for removal of the root canal fillings with retreatment files. The data were analyzed using 1-way analysis of variance and post hoc Games-Howell tests for dentinal tubule penetration and the Kruskal-Wallis test for retreatment time. RESULTS: Significantly greater sealer penetration and sealer-penetrated area was achieved when the sealer was used with a .04 gutta point (P < .05), whereas there was no difference between the sealer and .02 gutta point groups (P > .05). All test groups showed a similar depth of sealer penetration (P > .05). Groups with the gutta-percha points required a similar time to remove root filling (P > .05), whereas the working length could not be achieved in the sealer group. CONCLUSIONS: The use of a matched-taper bioceramic gutta-percha point enhanced the dentinal tubule penetration of the tested tricalcium silicate-based sealer. The use of a core material in conjunction with sealer facilitates removal of the root filling to the working length.

Effect of ultrasonic activation on dentinal tubule penetration of calcium silicate-based cements.

This study investigated the dentinal tubule penetration of mineral trioxide aggregate (MTA), NeoMTA Plus and Biodentine placed by either manual condensation or ultrasonic activation in simulated open apex model. Standardized divergent open apex models were created using palatal roots of 60 human maxillary molars and divided into six groups according to the used cements and activation methods (n = 10): MTA-manual condensation, MTA-ultrasonic activation, NeoMTA Plus-manual condensation, NeoMTA Plus-ultrasonic activation, Biodentine-manual condensation, Biodentine-ultrasonic activation. For the measurement of penetration, the cements were mixed with 0.1% Rhodamin B and 6-mm apical portions of each root canal were obturated in an orthograde direction. The roots were embedded into acrylic blocks, and 1-mm-thick sections were obtained at 3 mm from the apex. Specimens were mounted onto glass slides and scanned under a confocal laser scanning microscope (CLSM) and stereomicroscope. Dentinal tubule penetration areas, depth and percentage were measured using LSM and ImageJ software. The data were analyzed using two-way analysis of variance (anova) with Bonferroni correction (α = 0.05). No correlation was found between stereomicroscope and CLSM analyses (p > .05). CLSM analysis showed no significant differences between MTA, NeoMTA Plus, and Biodentine groups when manual condensation was used (p > .05). Ultrasonic activation did not increase the tubular penetration of MTA, NeoMTA Plus or Biodentine as compared to manual condensation of each material (p > .05). MTA, NeoMTA Plus and Biodentine showed similar tubular penetration when manual condensation was used. Ultrasonic activation of these cements had no effect on tubular penetration of each material as compared to the manual condensation counterparts.

Effect of phytic acid on the setting times and tensile strengths of calcium silicate-based cements.

This study aimed to evaluate and compare the effect of 1% phytic acid as a mixing medium on the setting times and diametral tensile strengths of different calcium silicate-based cements. Specimens for four experimental groups (n = 20/each) were fabricated by mixing ProRoot MTA® (Dentsply) and Biodentine® (Septodont) powders with their original liquids or with 1% phytic acid. Half of the samples in each group were immediately subjected to setting time tests, whereas the remaining half was subjected to the diametral tensile strength test after 3 weeks. When mixed with their original liquids, the setting time of MTA was significantly longer than that of Biodentine® (P < 0.05). When mixed with phytic acid, the initial and final setting times of both test materials significantly decreased (P < 0.05). The diametral tensile strength of Biodentine® was significantly greater than that of MTA (P < 0.05). However, phytic acid had no effect on this outcome (P > 0.05).

Reinforcing Effect of Glass Fiber-incorporated ProRoot MTA and Biodentine as Intraorifice Barriers.

INTRODUCTION: The purpose of this study was to investigate the fracture resistance of roots by using intraorifice barriers with glass fiber-incorporated ProRoot MTA and Biodentine. METHODS: The diametral tensile strength and compressive strength of ProRoot MTA and Biodentine were determined after incorporation of 5 wt% and 10 wt% alkali resistant (AR) glass fiber powder into both cements. On the basis of higher diametral tensile strength and compressive strength values, ProRoot MTA and Biodentine with 5 wt% AR glass fiber were selected for further testing as intraorifice barriers. The 14-mm-long root specimens obtained from extracted mandibular premolars (n = 60) were prepared with nickel-titanium rotary files and obturated with gutta-percha + AH Plus sealer. After removal of coronal 3 mm of root fillings, the roots were grouped with respect to the intraorifice barrier material (n = 12/group): (1) ProRoot MTA, (2) ProRoot MTA with 5 wt% AR glass fibers, (3) Biodentine, (4) Biodentine with 5 wt% AR glass fibers, and (5) control (no intraorifice barrier). The specimens were loaded vertically at 1 mm/min crosshead speed until vertical root fracture occurred. The data were evaluated statistically by using 2-way analysis of variance and Tukey tests. RESULTS: Both incorporation of glass fiber and the type of material significantly affected fracture resistance (both P = .002). Roots with glass fiber-reinforced Biodentine barriers showed the highest fracture strength (P = .000). CONCLUSIONS: Incorporation of 5 wt% AR glass fiber can significantly improve the reinforcement effect of ProRoot MTA and Biodentine when used as intraorifice barriers.

Effect of timing of post space preparation on the apical seal when using different sealers and obturation techniques.

BACKGROUND/PURPOSE: To prepare the post apace, some of the root-canal filling material has to be removed, which can affect the apical seal. The aim of this study was to compare the effect of immediate post space preparation to that of delayed post space preparation on apical sealing using three different endodontic sealers and obturation techniques. MATERIALS AND METHODS: In total, 90 decrowned single-rooted human teeth were studied. After root canals were prepared with 0.06 tapered nickel-titanium rotary files to size 30, the roots were categorized randomly into three experimental groups according to the obturation material: (1) AH plus/gutta-percha; (2) Sealite Ultra/gutta-percha; and (3) Epiphany/Resilon. Furthermore in all groups, specimens were categorized randomly into three subgroups according to the obturation technique (n = 10): (1) single cone; (2) cold lateral compaction; and (3) System B + Obtura. After root-canal filling, post space preparation was immediately performed in Group 1, after 24 hours in Group 2, and after 7 days in Group 3. Apical leakage was measured using the fluid-filtration method. Statistical analysis was performed using the Kruskal-Wallis test and Wilcoxon signed ranks test at P < 0.001. RESULTS: Regardless of the obturation technique and sealers used, significantly better (P < 0.001) sealing was achieved at the apical ends using delayed post space preparation than with immediate post preparation. The obturation techniques tested did not significantly affect leakage values. The following statistical ranking of fluid filtration values was obtained for the obturation materials: Epiphany/Resilon > Sealite Ultra/gutta-percha > AH plus/gutta-percha (P < 0.001). CONCLUSION: To reduce apical leakage, clinicians should use AH plus together with any of the obturation techniques after 7 days of obturation.

Effect of endodontic chelating solutions on the bond strength of endodontic sealers.

The purpose of this in vitro study was to evaluate the effect of various chelating solutions on the radicular push-out bond strength of calcium silicate-based and resin-based root canal sealers. Root canals of freshly-extracted single-rooted teeth (n = 80) were instrumented by using rotary instruments. The specimens were randomly divided into 4 groups according to the chelating solutions being tested: (1) 17% ethylenediaminetetraacetic acid (EDTA); (2) 9% etidronic acid; (3) 1% peracetic acid (PAA); and (4) distilled water (control). In each group, the roots were further assigned into 2 subgroups according to the sealer used: (1) an epoxy resin-based sealer (AH Plus) and (2) a calcium silicate-based sealer (iRoot SP). Four 1 mm-thick sections were obtained from the coronal aspect of each root (n = 40 slices/group). Push-out bond strength test was performed at a crosshead speed of 1 mm/min., and the bond strength data were analyzed statistically with two-way analysis of variance (ANOVA) with Bonferroni's post hoc test (p < 0.05). Failure modes were assessed quantitatively under a stereomicroscope. Irrespective of the irrigation regimens, iRoot SP exhibited significantly higher push-out bond strength values than AH Plus (p < 0.05). For both the sealers, the use of chelating solutions increased the bond strength, but to levels that were not significantly greater than their respective controls (p > 0.05). iRoot SP showed higher resistance to dislocation than AH Plus. Final irrigation with 17% EDTA, 9% Etidronic acid, and 1% PAA did not improve the bond strength of AH Plus and iRoot SP to radicular dentin.

Effect of endodontic chelating solutions on the bond strength of endodontic sealers

The purpose of this in vitro study was to evaluate the effect of various chelating solutions on the radicular push-out bond strength of calcium silicate-based and resin-based root canal sealers. Root canals of freshly-extracted single-rooted teeth (n = 80) were instrumented by using rotary instruments. The specimens were randomly divided into 4 groups according to the chelating solutions being tested: (1) 17% ethylenediaminetetraacetic acid (EDTA); (2) 9% etidronic acid; (3) 1% peracetic acid (PAA); and (4) distilled water (control). In each group, the roots were further assigned into 2 subgroups according to the sealer used: (1) an epoxy resin-based sealer (AH Plus) and (2) a calcium silicate-based sealer (iRoot SP). Four 1 mm-thick sections were obtained from the coronal aspect of each root (n = 40 slices/group). Push-out bond strength test was performed at a crosshead speed of 1 mm/min., and the bond strength data were analyzed statistically with two-way analysis of variance (ANOVA) with Bonferroni’s post hoc test (p < 0.05). Failure modes were assessed quantitatively under a stereomicroscope. Irrespective of the irrigation regimens, iRoot SP exhibited significantly higher push-out bond strength values than AH Plus (p < 0.05). For both the sealers, the use of chelating solutions increased the bond strength, but to levels that were not significantly greater than their respective controls (p > 0.05). iRoot SP showed higher resistance to dislocation than AH Plus. Final irrigation with 17% EDTA, 9% Etidronic acid, and 1% PAA did not improve the bond strength of AH Plus and iRoot SP to radicular dentin.

Debris and irrigant extrusion potential of 2 rotary systems and irrigation needles.

The purpose of this study was to compare the amount of apically extruded irrigant using 2 Ni-Ti rotary systems. Forty mandibular premolars with single canals were randomly assigned into 4 groups. Flower arrangement foam cubes were weighed with a precision balance before being attached to the apical portions of all teeth. In group 1, preparation was completed with ProTaper files. In group 2 canals were prepared with RaCe files. In groups 1 and 2, the irrigant was delivered with a 30-gauge conventional dental needle. In groups 3 and 4, teeth were prepared as in groups 1 and 2 with the exception that the irrigant was delivered with a side-vented irrigation needle. The weight of the extruded material (irrigant and debris) for each group was calculated by comparing the pre- and postinstrumentation weights of the foams used for periapical modeling. Obtained data were analyzed by Kruskal-Wallis and Mann-Whitney U tests, with P equals .05 as the level for statistical significance. ProTaper files used with regular needle irrigation had the highest fluid extrusion. The lowest irrigant extrusion was observed with the RaCe system combined with a side-vented irrigation needle. Within the limitations of this study, it can be concluded that irrigation needle and rotary instruments have an effect on the amount of extruded root canal irrigant.

Effect of different intraorifice barriers on the fracture resistance of roots obturated with Resilon or gutta-percha.

INTRODUCTION: This study investigated and compared the root reinforcement potential of 3 different intraorifice barriers (mineral trioxide aggregate [MTA], resin-modified glass ionomer cement [Vitremer], and fiber-reinforced composite [FRC]) placed over root canals obturated with gutta-percha or Resilon. METHODS: Crowns of 80 extracted human mandibular premolars were sectioned off to obtain 14-mm-long root specimens. After preparation of root canals with nickel-titanium rotary files, the roots were obturated with either the Resilon/Epiphany system or gutta-percha + AH Plus sealer. In both obturation groups, specimens were further subgrouped with respect to the intraorifice barrier material placed after removal of 3-mm coronal portion of the root fillings: (1) MTA, (2) Vitremer, and (3) FRC. The specimens were loaded vertically at 1 mm/min crosshead speed until vertical root fracture occurred. Results were evaluated statistically with two-way analysis of variance and Tukey tests. RESULTS: Fracture resistance of roots was significantly affected by the type of intraorifice barrier (P < .05), but not by the type of obturation system used (P > .05). CONCLUSIONS: The use of Vitremer and FRC significantly improved the fracture resistance, whereas MTA did not exhibit any reinforcing effect as an intraorifice barrier.