ABSTRACT Aim: To evaluate the effect of different post space irrigation protocols on the push-out bond strength of fiber posts cemented using self-adhesive and adhesive dual-cure resin cements. Methods: Thirty-six extracted single-rooted human maxillary central incisors were endodontically treated and decoronated. Post spaces were prepared, and specimens were randomly assigned to irrigating solutions: sodium hypochlorite (NaOCl), HEBP (etidronic acid), and saline. Fiber posts were cemented using either a self-adhesive or an adhesive dual-cure resin cement. Specimens were sectioned and subjected to push-out bond strength testing using a universal testing machine. Data were analyzed using two-way analysis of variance followed by Tukey’s post hoc test, with the level of significance set at P < 0.05. Results: Both the irrigating solution and resin cement type significantly influenced bond strength ( P < 0.05), with no significant interaction ( P > 0.05). The HEBP group demonstrated higher bond strength (9.69 ± 0.38 MPa for self-adhesive cement and 7.95 ± 0.45 MPa for adhesive cement) compared with NaOCl (9.24 ± 0.33 MPa and 7.80 ± 0.71 MPa, respectively) and saline (6.31 ± 0.33 MPa and 6.01 ± 0.36 MPa). Self-adhesive cement demonstrated significantly higher bond strength than adhesive cement ( P < 0.001). Conclusion: Within the limitations of this in vitro study, post space irrigation protocols influenced the bond strength of fiber posts. HEBP irrigation demonstrated improved bonding performance compared with NaOCl and saline. However, these findings should be interpreted with caution due to the limited sample size and absence of long-term clinical simulation.
ABSTRACT Aim: The objective of the study was to assess and compare the effect of ultrasonic activation (UA) on intratubular penetration and pushout bond strength (POBS) to root canal dentin of five distinct endodontic sealers. Methods: One hundred extracted human single-rooted teeth were decoronated and standardized to 16 mm root length. After instrumentation with WaveOne Gold #45.06, the samples were divided into five groups (n = 20 each) according to sealer type: AH26, Pulp Canal Sealer (PCS), BioRoot RCS (BRS), MTA Fillapex (MTAF), and Nanoseal-S, and further subdivided into ultrasonic and nonultrasonic activation groups. Sealers were mixed with Rhodamine B dye for visualization. UA was performed using a noncutting tip, followed by obturation with WaveOne Gold gutta-percha and lateral condensation. The samples were transversely sectioned at two specific levels: 8 mm and 12 mm from the apex. Middle-third slices were analyzed under confocal laser scanning microscopy for sealer penetration, whereas coronal-third slices were subjected to POBS testing. Results: UA significantly improved both sealer penetration and bond strength (P < 0.05). BRS (73.10 µm) showed the greatest penetration, followed by AH26 (68.80 µm), with the least in PCS (48.10 µm). MTAF (55.80 µm) and Nanoseal-S (54.40 µm) demonstrated comparable penetration. For bond strength, AH26 (41.5 MPa) and BRS (39.4 MPa) performed similarly and were superior to MTAF (20.6 MPa) and Nanoseal-S (21.4 MPa), whereas PCS showed the lowest value (10.8 MPa). Conclusion: UA improved the intratubular penetration and POBS of all tested sealers. BRS showed the highest penetration, whereas AH26 and BRS exhibited superior bond strength. PCS demonstrated the weakest performance in both parameters.
ABSTRACT Aim: This study aimed to evaluate the influence of different surface treatments on the push-out bond strength (PBS) and surface morphology of glass fiber posts (GFPs) and to assess failure modes. Methods: Sixty GFPs were assigned to five groups: Silane; 1.23% acidulated phosphate fluoride (APF) + Silane; 30% hydrogen peroxide (H 2 O 2 ) + Silane; 9.6% hydrofluoric acid (HF) + Silane; and Silane + universal bonding agents. Fifty single-rooted premolars were prepared, obturated, and restored with posts luted using dual-cure resin cement. Three 1-mm sections (coronal, middle, and apical) were obtained for PBS testing. Surface topography and failure modes were evaluated using scanning electron microscopy. Data were analyzed using Analysis of Variance (ANOVA) and Tukey HSD tests. Results: The highest PBS was observed in the 30% H 2 O 2 + silane group, particularly in the cervical region (22.39 ± 0.60 MPa, n = 10), followed by HF + silane (19.63 ± 0.32 MPa) and APF + silane (18.91 ± 0.40 MPa). The silane-only group showed the lowest bond strength (16.61 ± 0.24 MPa). Bond strength decreased significantly from cervical to apical regions across all groups. One-way ANOVA revealed statistically significant differences among all groups ( P < 0.001). Adhesive failure was the predominant mode (68.7%), with no significant difference in failure distribution among groups ( P = 0.673). Conclusion: Thirty percent H 2 O 2 + Silane improved the PBS of GFPs while preserving its surface integrity.
ABSTRACT Aim: This study aims to evaluate the canal centering ability (CCA) of novel rotary files used in conventional sequence and as a single file system, in curved canals of extracted molars using cone-beam computed tomography (CBCT) Methods: Mesial canals of mandibular molars, with closed apices and within the curvature limits of 15°–45° were selected. After access opening and working length determination, pre-instrumentation measurements from the outer root surface to the root canal periphery were done using CBCT. Teeth were randomly grouped as: Group 1 – NT Rainbow S (NTRBS) conventional sequence, Group 2 – NTRBS single file, Group 3 – Jizai conventional sequence, and Group 4 – Jizai, single file. Pre- and postinstrumentation CBCT measurements were used to calculate CCA. Results: The mixed-design repeated-measures analysis of variance demonstrated no statistically significant main effect of group for the buccolingual direction of the mesiobuccal canal ( P = 0.057) and mesiodistal direction of the mesiolingual canal ( P = 0.955) across indicating canal transportation across all levels. Group 2 NTRBS single file showed the least canal transportation compared to the other groups, and the most canal transportation was observed with Group 3 – Jizai conventional sequence, though differences were statistically non-significant Conclusion: Both the rotary systems exhibited canal transportation when used in conventional sequence and as a single-file system across all levels. NTRBS as a single-file system exhibited the least canal transportation. However, the potential benefits of rotary files, when used as a single file system, should be evaluated.
Aim: This study aimed to evaluate and compare the effect of three different intra-orifice barrier (IOB) materials – dual cure resin (DCR) cement, Giomer, and Biodentine – at two depths (3 mm and 5 mm) on the fracture resistance of endodontically treated teeth (ETT). Methods: Thirty-five extracted single-rooted human teeth were biomechanically prepared and obturated with gutta-percha. Following obturation, specimens were randomly allocated into seven groups based on the IOB material and placement depth. Groups 1 and 2 received DCR cement at 3 mm and 5 mm, respectively; Groups 3 and 4 received Giomer at 3 mm and 5 mm; Groups 5 and 6 received Biodentine at 3 mm and 5 mm; Group 7 served as the control without any barrier. All samples were stored in 100% humidity at 37°C for 1 week. Subsequently, the specimens were mounted in acrylic and subjected to vertical compressive load using a universal testing machine to determine fracture resistance. Results: All IOB groups demonstrated significantly higher fracture resistance than the control group. Among the tested materials, Biodentine yielded the highest fracture resistance, followed by Giomer and DCR cement. In addition, barriers placed at 5 mm depth showed significantly superior resistance compared to those at 3 mm. Statistical significance was confirmed using one-way analysis of variance and Post hoc Tukey tests (SPSS v23). Conclusion: IOBs enhance the fracture resistance of ETT, with greater reinforcement observed at 5 mm placement depth. Biodentine, especially at 5 mm, was the most effective material, emphasizing the benefit of deeper placement of bioactive barriers in reinforcing ETT.
