树脂类根管封闭剂粘接耐久性的研究进展

树脂类封闭剂是新型的根管充填封闭剂,具有良好的牙本质粘接能力、稳定的理化性和较好的生物相容性等优点,但因其聚合收缩、吸水降解等缺点使其在长期的口内功能状态下对根管的密闭性能受到影响,进而导致根管治疗失败.通过检测不同树脂类封闭剂与根管牙本质粘接耐久性,筛选粘接耐久性较好的封闭剂可提高根管治疗成功率.     

Cytotoxicity of three resin-based root canal sealers: an in vitro evaluation

Abstract— The cytotoxicity of three resin-based root canal sealers (AH26, AH-Plus, Topseal) was evaluated in vitro. The experiments included two cell lines, L929 mouse skin fibroblasts and RPC-C2A rat pulp cells. The cytotoxicity was assessed by sulforodamine B (SRB) colorimetric assay and hemocytometer viable cell counting after 24- and 48-h exposure. AH26 had a severe cytotoxic effect whilst Topseal and AH-Plus showed a markedly lower toxic influence on the cells during the experimental period.     

Retreatability of three calcium silicate-containing sealers and one epoxy resin-based root canal sealer with four different root canal instruments

Clinical Oral Investigations - The objective of the study was to compare the retreatability of three calcium silicate-containing sealers (BioRoot RCS, MTA Fillapex, Endo C.P.M.) and an epoxy...     

Polymerization stress, flow and dentine bond strength of two resin-based root canal sealers

Aim  To compare two resin-based root canal sealers (AH Plus and dual cure Epiphany) in terms of flow, polymerization stress and bond strength to dentine.
Methodology  Flow was evaluated by measuring the diameter of uncured discs of sealer (0.5 mL) after 7 min compression (20N) between two glass plates ( n  = 5). Polymerization stress was monitored for 60 min in 1-mm thick discs bonded to two glass rods (Ø = 5 mm) attached to a universal testing machine ( n  = 3). Bond strength was analyzed through micropush-out test ( n  = 10) and failure mode was examined with scanning electron microscope (100× and 2500×). Data were statistically analyzed using the Student's t -test (α = 0.05).
Results  Polymerization stress was 0.32 ± 0.07 MPa for Epiphany self-cure, 0.65 ± 0.08 MPa for Epiphany light-cure and zero for AH Plus ( P  < 0.05). Flow data and bond strength values were 30.9 ± 1.1, 28.6 ± 0.7 mm and 6.3 ± 5.3, 17.8 ± 7.5 MPa for Epiphany and AH Plus, respectively ( P  < 0.001). Failure mode was predominantly cohesive in the sealer for both materials.
Conclusions  Epiphany had higher flow and polymerization stress and lower bond strength values to dentine than AH Plus. In view of these findings it can be implied that AH Plus would provide a better seal.     

In vitro cytotoxicity evaluation of a self-adhesive, methacrylate resin-based root canal sealer

This study compared the cytotoxicity of MetaSEAL (Parkell Inc, Farmington, NY), a methacrylate resin-based sealer with an epoxy resin-based (AH Plus Jet; Dentsply Caulk, Milford, DE) and a zinc oxide-eugenol-based sealer (Pulp Canal Sealer; SybronEndo, Orange, CA). Five-millimeter diameter disks prepared from the respective sealer and disks prepared from Teflon (negative control) and polymethyl methacrylate (positive control) were placed in direct contact with a rat osteosarcoma (ROS) 17/2.8 rat osteoblast-like cell line at six intervals after setting completely at 72 hours and for 5 succeeding weeks after the disks were immersed in simulated body fluid. Succinate dehydrogenase activity was evaluated by using 3-(4,5-dimethylthiazole-2-yl)-2,5-diphenyl tetrazolium bromide assay. All sealers exhibited severe toxicity at 72 hours, after which toxicity decreased gradually over the experimental period except for Pulp Canal Sealer, which remained severely toxic. MetaSEAL was more toxic than AH Plus Jet during the first week. Both were similar to the toxicity profile of the positive control after the first week, which was probably diffusion controlled.     

Effect of gutta-percha solvents on the bond strength of two resin-based sealers to root canal dentin

Objective. To evaluate the effect of two gutta percha solvents on the bond strength of two resin-based sealers to root canal dentin. Materials and methods. Root canals of extracted single rooted human mandibular premolars (n = 60) were decoronated and instrumented with a rotary NiTi system to an apical size of 40 and randomly divided into three groups (n = 20) based on the chemical treatment: Group I, saline (control); group II, Xylene and group III, Endosolv E. All groups were divided into two sub-groups (n = 10) based on the root filling material: sub-group A, epoxy resin sealer (AH Plus); sub-group B, methacrylate resin sealer (Epiphany). Roots were then sectioned and push-out tests were performed. The data was analysed using two-way analysis of variance (ANOVA) and a multiple comparison test (p = 0.05). Results. There was a significant difference in bond strength of both sealers between the control and test groups (p < 0.05). The bond strength of the epoxy resin sealer (sub-group A) in group II was significantly lower than in group III (p < 0.05). However, there was no significant difference between groups II and III for the methacrylate resin sealer (sub-group b) (p > 0.05). Conclusions. Gutta Percha solvents had an adverse effect on bond strengths of resin sealers to root canal dentin. This was dependent on the chemistry of the solvent and the sealer.     

Allergenic potential of root canal sealers

Abstract The sensitizing potential of 4 root canal sealers, Endo-methasone, ProcoSol, AH26, and Kloroperka N-Ø, was evaluated in a modified guinea pig maximization test. All 4 materials induced sensitivity. When single components of the sealers were used in subsequent skin challenges of the same animals, positive responses were elicited by eugenol and thymol iodide in Endométhasone, eugenol in ProcoSol, epoxy resin in AH26, and chloroform in Kloroperka N-Ø. As reports on hypersensitivity reactions after endodontic treatment are rare, the demonstrated capability of the sealers to induce a delayed hypersensitivity reaction may seem to be of minor clinical significance. However, a possible allergic reaction should be considered in endodontic patients with complicated postoperative symptoms. Furthermore, the potential for the sealers to cause dermatological problems to the professionals handling them should not be overlooked.     

Solubility and apical sealing characteristics of a new calcium silicate-based root canal sealer in comparison to calcium hydroxide-, methacrylate resin- and epoxy resin-based sealers

Abstract

Aim. To assess and compare the water sorption, solubility and apical sealing ability of iRoot SP and three other widely used root canal sealers. Materials and methods. Solubility was assessed by immersing standardized samples of calcium silicate- (iRoot SP), calcium hydroxide- (Sealapex), methacrylate resin- (EndoREZ) and epoxy resin- (AH Plus) based sealers in distilled water and measuring weight gain and weight loss at 6 h, 24 h and daily for 14 days. Roots of extracted mandibular premolars (n = 80) were prepared with 0.04-taper nickel-titanium rotary files to a final size 40. Roots were then randomly divided into four experimental groups (n = 18) and two control groups (n = 4), root canal sealers were applied and apical leakage was assessed using the fluid filtration method. Data was analyzed using Kruskal Wallis analysis of variance and Mann-Whitney U-tests, with the level of significance set at p ≤ 0.05. Results. EndoREZ exhibited the highest water sorption, followed by iRoot SP, Sealapex and AH Plus. Sealapex exhibited significantly higher solubility than the other sealers, whereas no significant differences in solubility levels were observed between the other three sealers tested. AH Plus exhibited significantly lower microleakage than Sealapex and EndoREZ, whereas no difference in microleakage was found between AH Plus and iRoot SP. Conclusions. In view of the study findings, all tested sealers except Sealapex met the ANSI/ADA's requirements for solubility and no difference was found between AH Plus and iRoot SP in terms of apical sealing ability.     

Leakage of five root canal sealers

AIM: The aim of this study was to examine the apical sealing ability of five root canal sealers using a fluid transport model. METHODOLOGY: A comparison of root canal scalers AH26, AH Plus, Diaket, Apexit, and Ketac-Endo were tested on 60 single-rooted teeth. The coronal part of each tooth was removed at the amelo-cemento junction, and also 3 mm of the root tip. Root canals were instrumented using the 'step-back' technique with Gates Glidden drills and irrigated with 2.5% NaOCl. The specimens were divided into five groups of 10 samples each and filled with test materials and gutta-percha points by the cold lateral condensation technique. Ten teeth were used as a control group, out of which five served as negative and five as positive controls. The leakage was measured by the movement of an air bubble in a capillary glass tube connected to the experimental root section. RESULTS: The differences in leakage amongst Ketac-Endo (0.318 microL: SD 0.084), AH26 (0.319 microL; SD 0.075), AH Plus (0.330L; SD 0.085) Apexit (0.360 microL; SD 0.127) and Diaket (0.387 microL; SD 0.140) were not statistically significant (P > 0.05). CONCLUSIONS: Under the conditions of this study, all five sealers produced a satisfactory seal.     

Water sorption and solubility of resin-based materials following inadequate polymerization by a visible-light curing system

The water sorption and solubility of three hybrid and one microfine composite are reported. The values obtained are dependent on composite type and resin system. Incomplete polymerization of the two materials resulted in increased solubility and sorption due to incomplete conversion of the monomer. The marked increased in both parameters will have clinical significance on the durability of the material.