Assessment of the biocompatibility of Epiphany root canal sealer in rat subcutaneous tissues

Objective. The aim of this study was to evaluate the biocompatibility of the root canal sealer Epiphany in rat subcutaneous tissues. Study design. Polyethylene tubes were filled with the sealer (I: Epiphany; II: photoactivated Epiphany; III: Epiphany associated with self-etch primer; IV: photoactivated Epiphany associated with primer; and V: control group) and later implanted into 4 different regions of the dorsum of 15 adult male rats (Rattus novergicus, Albinus Wistar). After 7, 21, and 42 days, 5 animals were killed, obtaining 4 samples per group, in addition to the control group, at each analyzed time. Results. In all periods, Epiphany induced a mild inflammatory reaction. However, in group II, in which the primer was not used, extensive necrosis and a moderate to intense inflammatory reaction were observed, mainly after 7 and 21 days. Conclusion. Epiphany sealer appears biocompatible when tested on rat subcutaneous tissues.

Influence of endodontic sealers on the bond strength of carbon fiber posts

Objective: The aim of this study was to verify the influence of endodontic sealers on the bond strength of an adhesive system and a resin cement used for carbon posts cementation. Methods: Thirty extracted human premolars were instrumented and randomly divided into three groups according to the tested sealer: EndoFill, Sealapex, or EndoREZ. Specimens were stored at 37 degrees C. After 48 h, half of specimens were prepared to receive the post and the others after 7 days. The posts were cemented with Adper Single Bond/Rely X ARC and stored in distilled water at 37 degrees C for 7 days. After this period, the specimens were sectioned in three slices (coronal, middle, and apical). The push-out test was performed in a universal machine and the debonded area was examined in a stereomicroscope. Results: Data were submitted ANOVA and Tukey test (alpha = 0.05). The EndoFill showed lower bond strength than other sealers (p < 0.01). The EndoREZ sealer was statistically greater than other groups for coronal and middle portions and similar for apical portion (P > 0.05). Coronal and middle portions showed the best results for all groups, mainly when the canal preparation was performed after 48 h (p < 0.01). Mixed failure occurs with more frequency (55.6%) followed by failure in adhesive-dentin interface (34.4%) and adhesive-post interface (10.0%). Conclusion: The use of EndoREZ sealer promoted higher bond strength in root coronal and middle portions when carbon post was fixed with a resin cement. (C) 2007 Wiley Periodicals, Inc.

Clinical management and subsequent healing of teeth with horizontal root fractures

Horizontal root fractures are uncommon, mainly occurring on the cervical and middle third of the root of permanent upper incisors. The diagnosis is essentially radiographic and requires different healing patterns, depending on some pre- and postinjury factors. The aim of this article was to report the clinical management and different healing types in three cases of horizontal root fractures on permanent dentition. In case 1, the pulp tissue was vital and no treatment was necessary. In case 2, a root canal treatment of the cervical fragment was necessary and in case 3, pulpal necrosis was verified and an apical surgery was performed.

Influence of different endodontic filling materials on root fracture susceptibility

Objective: To evaluate the influence of different endodontic materials on root fracture susceptibility. Methods: Seventy-two mandibular incisors were sectioned 1 mm below the cementoenamel junction to obtain roots of 12 mm length. Roots were submitted to chemomechanical preparation with the rotary instruments of Profile system. The obturation of root canals were performed with the following filling materials (n = 12): GI, unfilled teeth (control); GII, Endofill + gutta-percha; GIII, Sealer 26 + gutta-percha; GIV, AH Plus + gutta-percha; GV, Epiphany + gutta-percha; GVI, Epiphany + Resilon. After the sealers setting time, each root was embedded in acrylic resin. The specimens were then submitted to fracture resistance test using an Instron testing machine at 1 mm/min. Results: The ANOVA test showed no significant statistical difference (p > .05) among GI (162.16 +/- 41.4N), GII (168.46 +/- 37.5N), GIII (164.83 +/- 35.7N), GIV (168.29 +/- 38.7N), GV (172.36 +/- 20.6N) and GVI (193.11 +/- 42.8N). Conclusion: The core materials (gutta-percha or Resilon) combined with the tested endodontic sealers are not able to increase the root fracture resistance in canals submitted to chemomechanical preparation. (c) 2007 Elsevier Ltd. All rights reserved.

Shear Bond Strength and Ultrastructural Interface Analysis of Different Adhesive Systems to Bleached Dentin

Background: It remains unclear as to whether or not dental bleaching affects the bond strength of dentin/resin restoration. Purpose: To evaluated the bond strength of adhesive systems to dentin submitted to bleaching with 38% hydrogen peroxide (HP) activated by LED-laser and to assess the adhesive/dentin interfaces by means of SEM. Study design: Sixty fragments of dentin (25 mm(2)) were included and divided into two groups: bleached and unbleached. HP was applied for 20 s and photoactivated for 45 s. Groups were subdivided according to the adhesive systems (n = 10): (1) two-steps conventional system (Adper Single Bond), (2) two-steps self-etching system (Clearfil standard error (SE) Bond), and (3) one-step self-etching system (Prompt L-Pop). The specimens received the Z250 resin and, after 24 h, were submitted to the bond strength test. Additional 30 dentin fragments (n = 5) received the same surface treatments and were prepared for SEM. Data were analyzed by ANOVA and Tukey`s test (alpha = 0.05). Results: There was significant strength reduction in bleached group when compared to unbleached group (P < 0.05). Higher bond strength was observed for Prompt. Single Bond and Clearfil presented the smallest values when used in bleached dentin. SEM analysis of the unbleached specimens revealed long tags and uniform hybrid layer for all adhesives. In bleached dentin, Single Bond provided open tubules and with few tags, Clearfil determined the absence of tags and hybrid layer, and Prompt promoted a regular hybrid layer with some tags. Conclusions: Prompt promoted higher shear bond strength, regardless of the bleaching treatment and allowed the formation of a regular and fine hybrid layer with less deep tags, when compared to Single Bond and Clearfil. Microsc. Res. Tech. 74:244-250, 2011. (C) 2010 Wiley-Liss, Inc.

Effect of Chelating Solutions on the Microhardness of Root Canal Lumen Dentin

Introduction: The greatest reduction in microhardness of the most superficial layer of dentin of the root canal lumen is desired. The use of chelating agents during biomechanical preparation of root canals removes smear layer, increasing the access of the irrigant into the dentin tubules to allow adequate disinfection, and also reduces dentin microhardness, facilitating the action of endodontic instruments. This study evaluated the effect of different chelating solutions on the microhardness of the most superficial dentin layer from the root canal lumen. Methods: Thirty-five recently extracted single-rooted maxillary central incisors were instrumented, and the roots were longitudinally sectioned in a mesiodistal direction to expose the entire canal extension. The specimens were distributed in seven groups according to the final irrigation: 15% EDTA, 10% citric acid, 5% malic acid, 5% acetic acid, apple vinegar, 10% sodium citrate, and control (no irrigation). A standardized volume of 50 mu L of each chelating solution was used for 5 minutes. Dentin microhardness was measured with a Knoop indenter under a 10-g load and a 15-second dwell time. Data were analyzed statistically by one-way analysis of variance and Tukey-Kramer multiple-comparison test at 5% significance level. Results: EDTA and citric acid had the greatest overall effect, causing a sharp decrease in dentin microhardness without a significant difference (p > .05) from each other. However, both chelators differed significantly from the other solutions (p < .001). Sodium citrate and deionized water were similar to each other (p > .05) and did not affect dentin microhardness. Apple vinegar, acetic acid, and malic acid were similar to each other (p > .05) and presented intermediate results. Conclusion: Except for sodium citrate, all tested chelating solutions reduced microhardness of the most superficial root canal dentin layer. EDTA and citric acid were the most efficient. (J Endod 2011;37:358-362)

Microtensile Bond Strength of Glass Fiber Posts Cemented with Self-adhesive and Self-etching Resin Cements

Purpose: To evaluate the bond strength of glass fiber posts to intraradicular dentin when cemented with self-etching and self-adhesive resin cements. Materials and Methods: Forty-eight single-rooted human teeth were decoronated, endodontically treated, post-space prepared and divided into 8 groups (n = 6). The glass fiber posts used were: Exacto (EA) (Angelus) and everStick (ES) (StichTeck), which were cemented with two self-adhesive resin cements: BisCem (BIS) (Bisco) and Rely-X Unicem (UNI) (3M/ESPE), and two self-etching resin cements: Esthetic Cementing System NAC100 (NAC) (Kuraray) and Panavia-F (PAN) (Kuraray). Specimens were thermocycled between 5 degrees C and 55 degrees C for 1000 cycles and stored in water at 37 degrees C for 1 month. Four 1-mm-thick (in cross section) rods were obtained from the cervical region of the roots. Specimens were then subjected to microtensile testing in a special machine (BISCO; Schaumburg, IL, USA) at a crosshead speed of 0.5 mm/min. Microtensile bond strength (mu TBS) data were analyzed with two-way ANOVA and Tukey`s tests. Results: Means (and SD) of mu TBS (MPa) were: EA/PAN: 10.3 (4.1), EA/NAC: 14 (5.1) EA/BIS: 16.4 (4.8), EA/UNI: 19.8 (5.1), ES/PAN: 25.9 (6.1), ES/NAC: 29.1 (7), ES/BIS: 28.9 (6), ES/UNI: 30.5 (6.6). ANOVA indicated significant differences among the groups (p < 0.001). Mean mu TBS values obtained with ES post were significantly higher than those obtained with EA (p < 0.001). For EA, Tukey`s test indicated that higher mu TBS means were obtained with the self-adhesive resin cements (BIS and UNI), which were statistically significantly different (p < 0.05) from values obtained with the self-etching resin cements (PAN and NAC). Different cements had no significant effects on the bond strength values of ES post (p > 0.05). mu TBS values obtained with ES post were significantly higher than those obtained with EA post irrespective of the resin cement used. Conclusion: everStick posts resulted in the highest mean mu TBS values with all cements. Self-adhesive cements performed well in terms of bond strength.