Comparative Evaluation of Physicochemical Properties and Apical Sealing Ability of a Resin Sealer Modified with Pachymic Acid.

Objective: The addition of pachymic acid (PA) to AH Plus (an epoxy resin sealer) offsets the cytotoxicity of the latter. Prior to the clinical implementation of this formulation, a thorough knowledge of its physicochemical properties and sealing ability becomes mandatory. Hence, this in vitro study aimed to characterize and evaluate the physicochemical properties and apical sealing ability of AH Plus (AHP) with and without the addition of PA. Methods: Flow, setting time, film thickness, solubility and radiopacity of AHP (group 1) and AHP modified with PA (AHP/PA, group 2) were evaluated in accordance with the guidelines put forth by ISO 6876:2012. The percentage was determined under each parameter. Apical sealing ability was assessed using fluid filtration device. An independent samples t-test was used for inter- and intra-group comparisons of mean fluid flow (MFF). Results: Incorporating PA to AHP decreased its flow, setting time and film thickness by 24.34%, 2.14% and 31.71% respectively. The solubility of group 2 increased on day 1 by 85.71% and decreased on days 3, 7 and 14 by 46.67%, 34.79% and 13.8% respectively. The radiopacity of AHP was not altered by the addition of PA. MFF rates of group 2 was significantly higher than group 1 on day 1, but not significantly different on day 7. Conclusion: AHP/PA exhibited physicochemical properties that were within the requirements of ISO and with time, and showed fluid flow similar to AHP.

Effect of proanthocyanidin and bamboo salt on the push-out bond strength of an epoxy resin sealer to sodium hypochlorite-treated root dentin: An in vitro study.

BACKGROUND: In endodontic therapy, final irrigation is often done with sodium hypochlorite (NaOCl). This jeopardizes the bond strength between the epoxy resin sealer, used subsequently in obturation and radicular dentin. This study aimed to analyze the effect of natural antioxidants, 6.5% proanthocyanidin (PA) and 25% bamboo salt (BS) on the reversal of NaOCl-induced reduced bond strength of an epoxy resin sealer to dentin. MATERIALS AND METHODS: Thirty-three single-rooted extracted human teeth were randomly divided into three groups based on the final irrigation protocol: group 1 (saline), Group 2 (6.5% PA), and Group 3 (25% BS). The canals were cleaned, shaped, and obturated with gutta-percha and AH Plus sealer. 1.5 mm-thick root slices made from coronal, middle, and apical thirds of the canal were subjected to push-out bond strength (PBS) testing. The data were statistically analyzed using Kruskal-Wallis and Dunn's post hoc test (P < 0.05). RESULTS: 5.25% NaOCl significantly decreased the bond strength of AH Plus to dentin (P < 0.05). Both 6.5% PA and 25% BS were capable of reversing the compromised PBS of AH Plus to NaOCl-treated dentin. CONCLUSION: Final irrigation with antioxidants such as PA and BS eliminates the risk of reduced bond strength of AH Plus to root canal walls, which ensues following the use of NaOCl as an irrigant.

Effect of Indigenously Developed Nano-Hydroxyapatite Crystals from Chicken Egg Shell on the Surface Hardness of Bleached Human Enamel: An In Vitro Study.

OBJECTIVE: The objective was to evaluate the effect of nano-hydroxyapatite (nHA) derived from chicken eggshell on bleached human enamel in comparison with commercial casein phophopeptide-amorphous calcium phosphate (CPP-ACP) paste using Vickers microhardness test. MATERIALS AND METHODS: nHA powder was prepared from chicken eggshell using combustion method. nHA slurry was prepared by mixing 1.8 g of nHA powder with 0.3 ml of distilled water. Forty intact maxillary anterior teeth were collected and decoronated, and the crowns were embedded in acrylic mold with the labial enamel surfaces exposed. Baseline microhardness evaluation was done (T0). The specimens were randomly divided into the following four groups (n = 10) based on the surface treatment of enamel: Group 1: no bleaching treatment; Group 2: bleaching with 30% hydrogen peroxide (HP) solution; Group 3: bleaching followed by the application of CPP-ACP; and Group 4: bleaching followed by the application of nHA. The specimens were stored in artificial saliva at 37°C for 2 weeks, after which they were subjected to Vickers microhardness test (T14). One-way ANOVA and Tukey's post hoc multiple comparison tests were used for statistical analysis (P < 0.05). RESULTS: Bleaching with HP significantly decreased the enamel microhardness. CPP-ACP and nHA derived from chicken eggshell increased the enamel microhardness significantly. There was no significant difference in microhardness values among the CPP-ACP and nHA groups. CONCLUSION: Nano-hydroxyapatite sourced from chicken eggshell was as effective as CPP-ACP in remineralizing and restoring the lost microhardness of bleached enamel.

A Comparative Evaluation of the Effect of the Addition of Pachymic Acid on the Cytotoxicity of 4 Different Root Canal Sealers-An In Vitro Study.

INTRODUCTION: Root canal sealers exhibit varying degrees of cytotoxicity to periapical tissues. This in turn results in inflammation, delayed wound healing, and even bone resorption. This study aimed to explore the effect of the addition of an antioxidant like pachymic acid on the cytotoxicity of 4 root canal sealers, namely, Tubliseal (Kerr, Romulus, MI), a zinc oxide eugenol-based sealer; AH Plus (Dentsply De Trey GmbH, Konstanz, Germany), an epoxy resin-based sealer; Sealapex (Kerr), a calcium hydroxide-based sealer; and EndoREZ (Ultradent Products, South Jordan, UT), a methacrylate resin-based sealer. METHODS: Sealers mixed according to the manufacturers' instructions formed the experimental groups. Subgroups were determined based on the absence (subgroup A) or addition (subgroup B) of pachymic acid. The experimental sealers were added to L929 mouse fibroblast cells immediately after mixing. Cell viability was evaluated by methylthiazoletetrazolium assay after 24 hours. Data were analyzed using 1-way analysis of variance. Intergroup comparisons were performed using the Kruskal-Wallis test, and intragroup comparisons were done using independent t and post hoc tests. RESULTS: All 4 sealers were cytotoxic but to varying degrees. In both the subgroups, Sealapex exhibited the lowest cytotoxicity followed by AH Plus, Tubliseal, and EndoREZ (P < .05). The addition of pachymic acid reduced the cytotoxicity of all the sealers except that of EndoREZ (P > .05). CONCLUSIONS: Calcium hydroxide-based Sealapex showed the least cytotoxicity compared with the other sealers. Pachymic acid could be a viable therapeutic agent to overcome the potential adverse effects associated with root canal sealers.

Evaluation of microshear bond strength and nanoleakage of etch-and-rinse and self-etch adhesives to dentin pretreated with silver diamine fluoride/potassium iodide: An in vitro study.

AIMS: The aim of this in vitro study was to comparatively evaluate the microshear bond strength (MSBS) of etch-and-rinse and self-etch (ER and SE) bonding systems to dentin pretreated with silver diamine fluoride/potassium iodide (SDF/KI) and nanoleakage at the resin-dentin interface using transmission electron microscope (TEM). SUBJECTS AND METHODS: Seventy-two dentin slabs of 3 mm thickness were prepared from extracted human permanent third molars and divided into four groups (n = 18) based on the dentin surface treatment as follows: (1) ER adhesive bonding without dentin pretreatment; (2) SDF/KI pretreatment of dentin followed by ER adhesive bonding; (3) SE adhesive bonding without dentin pretreatment; and (4) SDF/KI pretreatment of dentin followed by SE adhesive bonding. Resin composite was built on the dentin slabs to a height of 4 mm incrementally, and dentin-composite beams of approximately 1 mm 2 cross-sectional area were prepared. The beams were subjected to MSBS analysis, and the fractured surface was observed under scanning electron microscope to determine the mode of failure. The resin-dentin interface was examined under TEM for evaluation of nanoleakage. STATISTICAL ANALYSIS USED: One-way ANOVA followed by Tukey's post hoc multiple comparison tests. RESULTS: Pretreatment of dentin with SDF/KI increased the MSBS of ER and SE adhesives, though not statistically significant, except between Groups 2 and 3. In all the groups, the predominant mode of failure was adhesive followed by cohesive in resin, mixed and cohesive in dentin. TEM examination of resin-dentin interface showed that pretreatment with 38% SDF/KI reduced nanoleakage regardless of the type of bonding system used. CONCLUSIONS: Pretreatment of dentin with SDF/KI minimized nanoleakage at the resin-dentin interface without adversely affecting the bond strength of resin composite to dentin.

Evaluation of dentinal tubule occlusion and depth of penetration of nano-hydroxyapatite derived from chicken eggshell powder with and without addition of sodium fluoride: An in vitro study.

AIM: This in vitro study evaluated the degree of dentinal tubule occlusion and depth of penetration of nano-hydroxyapatite (nHAp) derived from chicken eggshell powder with and without the addition of 2% sodium fluoride (NaF) using scanning electron microscope (SEM) and confocal laser scanning microscope (CLSM). MATERIALS AND METHODS: nHAp was synthesized and characterized using X-ray diffraction and SEM-energy dispersive spectroscopy. Dentin discs were obtained from extracted teeth, pretreated with 17% ethylenediaminetetraacetic acid for 5 min and were divided into four groups based on the experimental agents as follows: Group 1: Untreated (control), Group 2: 2% NaF, Group 3: nHAp, Group 4: Combination of nHAp and 2% NaF. The treatment protocol was carried out for 7 days, after which the specimens were viewed under SEM and CLSM. STATISTICAL ANALYSIS USED: One-way ANOVA and Tukey's post hoc multiple comparison tests (P < 0.05). RESULTS: All the experimental agents occluded the dentinal tubules, but to varying degrees and depths. Specimens treated with the combination of nHAp and 2% NaF showed complete dentinal tubular occlusion and significantly greater depth of penetration than those treated with nHAp and 2% NaF alone. CONCLUSION: The combination of nHAp and 2% NaF was the most effective in occluding dentinal tubules.

Degree of conversion of two dentin bonding agents with and without a desensitizing agent using fourier transform infrared spectroscopy: An in vitro study.

OBJECTIVE: This in vitro study investigated the effect of a desensitizer on the degree of conversion of two bonding resins using Fourier transform infrared (FTIR) spectroscopy. MATERIALS AND METHODS: An etch-and-rise bonding resin and a self-etching adhesive resin were selected for the study. Vivasens (Ivoclar Vivadent) was used as a desensitizing agent. Grouping was done as follows: Group I: Adper Single Bond (n=10), Group II: Adper Single Bond + Vivasens (n=10), Group III: AdheSE One (n=10), Group IV: AdheSE One + Vivasens (n=10). The bonding resin alone was light cured for 20 seconds in groups I and III. For groups II and IV, 1 ml each of the bonding resin and the desensitizer was mixed in a vial and light cured for 20 seconds. The specimens were analysed using FTIR spectroscopy. RESULTS: Group II (Adper Single Bond + Vivasens) showed a significantly higher degree of conversion compared to Group I (Adper Single Bond). Comparing Groups III and IV, Group IV (AdheSE One + Vivasens) showed a significantly higher degree of conversion compared to Group III (AdheSE One). CONCLUSIONS: The degree of conversion is increased when a dentin bonding agent is used along with a desensitizer. Hence, this combination can be recommended to effectively control postoperative sensitivity.