The influence of voxel size and artifact reduction on the detection of vertical root fracture in endodontically treated teeth.

OBJECTIVE: The aim of this study was to evaluate the effect of voxel size and artefact reduction (AR) on the identification of vertical root fractures (VRFs) in endodontically treated teeth. METHODS: A total of a hundred sound, extracted human mandibular single-rooted premolars were decoronated, after which root canal preparation was performed, canals were filled with gutta percha by single cone technique. Randomly selected fifty specimens were fractured, repositioned and glued together. The teeth were examined with cone beam computed tomography (CBCT) in five different voxel sizes (0.125, 0.200, 0.250, 0.300, and 0.400 voxels). Two scans were performed for each tooth, one with AR and one without AR. Two radiologists evaluated the CBCT scans. RESULTS: All voxel dimensions were successful in detecting VRFs in CBCT scans. But as the voxel size increased, the percentage of detecting VRFs decreased. High accuracy, sensitivity, specificity and predictive values were found for VRF detection on CBCT scans. Accuracy and sensitivity values decreased (from 100 to 82) while voxel dimensions increased (from 0.125 to 0.400). High-resolution images (0.125, 0.200, and 0.250 voxels) caused an increase in sensitivity for detection of VRFs. AR did not affect the accuracy, sensitivity, specificity and predictive values for VRF detection on CBCT scans. CONCLUSIONS: High-resolution CBCT images resulted in an increase in sensitivity and specificity for detection of VRFs compared with lower-resolution CBCT images. The use of AR did not further improve its diagnostic potential.

Efficacy of Combined Use of Different Nickel-Titanium Files on Removing Root Canal Filling Materials.

INTRODUCTION: The aim of this study was to estimate the remaining amount of residual filling materials in root canals after retreatment using ProTaper Universal Retreatment (PTUR) files (Dentsply Maillefer, Ballaigues, Switzerland) alone or with the additional use of the Self-Adjusting File (SAF; ReDent-Nova, Ra'anana, Israel), Reciproc (VDW, Munich, Germany), or Hedström-files (H-file; VDW, Antaeos, Munich, Germany) with volumetric estimation using the stereologic method via cone-beam computed tomographic images. METHODS: Forty-eight mandibular premolars with single canals were used. The canals were instrumented with ProTaper rotary instruments up to F4 and filled with gutta-percha and AH26 sealer (Dentsply De Trey, Johnson City, TN). All the samples were placed into the silicone models. Samples were scanned with cone-beam computed tomographic imaging and assigned into 4 groups (n = 12) according to retreatment files: the PTUR system group, the PTUR system plus SAF group, the PTUR system plus Reciproc group, and the PTUR system plus H-file group. The specimens were rescanned after retreatment procedures, and the volume estimations of the remaining filling materials were performed using the stereologic method. Data were analyzed using Kruskal-Wallis and Dunn tests. RESULTS: There was no significant difference among the groups regarding mean percentage volumes of the filling materials before retreatment procedures (P > .05). None of the retreatment procedures provided complete removal of the filling materials. The additional use of the SAF did not significantly improve the removal of filling materials when compared with the PTUR system alone (P > .05). However, the additional use of Reciproc or hand H-files significantly improved the removal of filling materials when compared with the PTUR system alone (P < .05). CONCLUSIONS: The additional use of files with different motion kinetics improved the removal of root canal fillings; however, none of the systems completely removed the root canal filling material from the root canals.

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.

A comparison of residual smear layer and erosion following different endodontic irrigation protocols tested under clinical and laboratory conditions.

OBJECTIVE: To compare the smear layer removal efficacy and erosive effects of different irrigation protocols under clinical and laboratory conditions. MATERIALS AND METHODS: Mandibular third molars (n = 32) of 30-45 year-old patients were instrumented with rotary files and were randomly assigned to one of the following groups for final irrigation: (1) 5.25% NaOCl; (2) 17% EDTA; and (3) BioPure MTAD. Thereafter, the teeth were immediately extracted and processed for micromorphological investigation. In vitro specimen pairs were prepared by repeating the clinical experiments on freshly-extracted mandibular third molars. To compare open and closed systems, laboratory experiments were repeated on 32 additional teeth with enlarged apical foramen. The cleanliness of the root canals and the extent of erosion were assessed by environmental scanning electron microscopy. RESULTS: Specimens prepared under clinical and laboratory conditions had similar cleanliness and erosion scores (p > 0.05). Under both conditions, the tested solutions were more effective in removing the smear layer in the coronal and middle regions than in the apical one. Comparison of closed and open systems showed similar levels of cleanliness and erosion in all regions (p > 0.05), with the exception of 17% EDTA showing significantly higher levels of cleanliness and erosion in the apical third of open-end specimens. CONCLUSIONS: Based on clinical correlates of in vitro root canal cleanliness and erosion, laboratory testing of root canal irrigants on extracted teeth with closed apices can serve as a reliable method to simulate the clinical condition. EDTA was the most effective final irrigation solution in removing the smear layer at the expense of yielding the greatest erosive effect.

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.

Microleakage evaluation of roots filled with different obturation techniques and sealers.

OBJECTIVE: The aim of this study was to compare the apical seal of the Single-cone ProTaper gutta-percha technique and the lateral compaction technique in combination with 3 sealers (AH-26, Apexit, and Sealite-Ultra). STUDY DESIGN: Seventy extracted single-root teeth were used. Root canals were prepared with ProTaper rotary instruments. Six groups were formed: (I) Single-cone ProTaper gutta-percha with AH-26; (II) lateral compaction technique with AH-26; (III) Single-cone ProTaper gutta-percha with Apexit; (IV) lateral compaction technique with Apexit; (V) Single-cone ProTaper gutta-percha with Sealite-Ultra; and (VI) lateral compaction technique with Sealite-Ultra. The fluid conductance of each specimen was measured after the 7th and 30th days using a fluid filtration method. RESULTS: When lateral compaction was performed, all sealers showed similar levels of leakage (P > .05). Using the single-cone technique, Sealite-Ultra showed more leakage than the others (P < .05). Comparing filling techniques, there was a significant difference only in the Sealite-Ultra groups (P < .05). CONCLUSION: Single-cone ProTaper gutta-percha and lateral compaction techniques showed similar sealing effect.

Time-dependent decalcifying effects of endodontic irrigants with antibacterial properties.

The aim of this study was to investigate the extent of calcium ion (Ca(2+)) removal on root dentin after treatment with 1.25% NaOCl, 2.5% NaOCl, 5.25% NaOCl, 2% chlorhexidine (CHX), 2% iodine potassium iodide (IKI), and MTAD in 3 immersion time periods. Extracted human mandibular premolars were bisected longitudinally, and the root halves (n = 70) were isolated with nail varnish, leaving the root canal exposed. The specimens were immersed in the test solutions, during which the amount of Ca(2+) release into the solutions was determined at 5, 10, and 15 minutes by flame photometry. The decalcifying effect of 5%, 2.5%, and 1.25% NaOCl and 2% IKI significantly increased within time (P < .05), with 5% NaOCl extracting the greatest amount of Ca(2+) at all treatment times. For 2% CHX and distilled water, a significant increase in the amount of Ca(2+) extraction from root dentin was only evident at 10 minutes (P < .05) and did not change at 15-minute readings. Between the 5- to 10-minute and 10- to 15-minute intervals, the greatest amount of increase in the rate of Ca(2+) extraction from root dentin was observed in the 2.5% NaOCl group. At 15 minutes, 2% CHX and distilled water showed the least amount of change. Among the test solutions, MTAD extracted the least amount of Ca(2+) at 5 minutes.

Multidisciplinary approach for the treatment of an oblique root fracture: a case report.

This clinical case study describes a multidisciplinary modified technique for the treatment of an oblique root fracture. A-38-year old woman with a history of trauma and a broken tooth was referred to our clinic. There was an oblique crown fracture extending the coronal third of the root just underneath the cingulum of the crown. The patient was willing to keep her tooth in function by any means. Two weeks after root canal therapy the flap was raised. The coronal two third of the root canal was enlarged. An impression of the enlarged root canal and tooth surface with surrounding bone was taken. The flap was sutured and the impression was sent to the laboratory for the post-casting preparation. After 7 days, the flap was opened again and casting was cemented. The flap was sutured. Ten days after the second surgery, three anterior teeth were prepared and a final impression was taken for the preparation of porcelain crowns. Restoration was finished 15 days after the second operation. The patient is still under maintenance therapy and the 12 month results are presented in this report. Extraction may not be the only alternative for the root fractures. Even for fractures under the alveolar margin, alternative multidisciplinary approaches can be used to restore and allow the tooth to survive.

Intentional replantation for a periodontally involved hopeless incisor by using autologous platelet-rich plasma.

The aim of the present case is to describe the use of autologous platelet-rich plasma (PRP) in an intentional replantation procedure for a periodontally involved lower right central incisor with 18 months follow-up. Brief information is also given on the preoperative preparation of PRP in the dental office. PRP preparation is a new biotechnology, and the prepared material contains thrombocyte concentrates and high levels of growth factors. This material promotes healing time in a range of various sites. In this case, a tooth with severe periodontal breakdown was treated with PRP with intentional replantation procedure. This tooth was previously treated with root canal treatment and root planing. The tooth was extracted, and was replanted with autologous PRP. Clinical and radiographic follow-up for 18 months demonstrated new bone formation around the apical portion of the root and all clinical parameters indicated a trend of healing. The mobility of this previously grade III mobile incisor returned to normal limits. We speculate that intentional replantation with PRP application may induce wound healing and may induce bone formation.