OBJECTIVES: We aimed to compare the apical sealing properties of three endodontic sealers, namely, C-Root SP (C-R), iRoot SP, and GuttaFlow Bioseal (GFB) in vitro. METHODS: Eighty-two single-rooted premolars and anterior teeth were prepared by using M3 machine with nickel-titanium file and randomly divided into six experimental groups (n=12) and two control groups (n=5). Group A1: single-cone technique (SC)+C-R; group B1: SC+iRoot SP; group C1: SC+GFB; group A2: single-cone with ultrasonic activation (SU)+C-R; group B2: SU+iRoot SP; group C2: SU +GFB; group D: positive control group, and group E: negative control group. Dye penetration length and lateral root canal filling in each group were measured by dye penetration test. A scanning electron microscope (SEM) was used to observe the interface between gutta pertscha, root canal sealer, and dentin wall. Dye penetration length was measured and analyzed by Kruskal-Wallis test, and data on lateral root canal filling were evaluated using Chi-square. RESULTS: The dye penetration length in group A1 was lower than that in groups C1 and A2 (P<0.05) but was not significantly different from the other groups (P>0.05). Lateral root canal filling was not significantly different among all groups (P>0.05). SEM showed that GFB was slightly better than C-R and iRoot SP in binding to gutta pertcha and dentin wall. CONCLUSIONS GFB, C-R, and iRoot SP demonstrate excellent apical sealing ability. Under the conditions tested in this study, SU did not yield significantly improve the apical sealing ability of the three root canal sealers.
Root Canal Filling Materials/chemistry* ; Humans ; Gutta-Percha ; Microscopy, Electron, Scanning ; Root Canal Obturation/methods* ; Ceramics ; Dimethylpolysiloxanes ; Drug Combinations

Compared with cold lateral condensation and continuous wave of condensation which are classically used in clinical, newly emerging single-cone obturation technique is easy-to-operate as well as time-saving. Especially when combined with bioceramic root canal sealers of improved physicochemical and biological properties, single-cone obturation technique showed satisfactory short-term outcomes in clinical observations. However, difficulties still exist in avoiding the root canal overfilling and in operating the retreatment. Besides, the long-term effects of single-cone obturation with bioceramic sealers still remain unclear. This article makes an overview on the history and development of single-cone obturation ,and provides analysis of its pros and corns. Furthermore, we would also like to summarize its clinical application and look into its future improvements.
Epoxy Resins/chemistry* ; Gutta-Percha/chemistry* ; Retreatment ; Root Canal Filling Materials/therapeutic use* ; Root Canal Obturation/methods* ; Root Canal Therapy

The present investigation assessed the effect of acid etching on marginal adaptation of white- and gray-colored mineral trioxide aggregate (MTA) to apical dentin using microcomputed tomography (micro-CT) and scanning electron microscopy (SEM). Sixty-four extracted single-rooted human maxillary teeth were used. Following root-end resection and apical preparation, the teeth were equally divided into four groups according to the following root end filling materials: (i) white-colored MTA (WMTA), (ii) etched WMTA (EWMTA), (iii) gray-colored MTA (GMTA) and (iv) etched GMTA (EGMTA). After 48 h, the interface between root-end filling materials and the dentinal walls was assessed using micro-CT and SEM. Data were statistically analyzed using the Kruskal-Wallis and Dunn tests. Micro-CT analysis revealed gap volumes between the apical cavity dentin walls and EGMTA, GMTA, EWMTA and WMTA of (0.007 1±0.004) mm(3), (0.053±0.002) mm(3), (0.003 6±0.001) mm(3) and (0.005 9±0.002) mm(3) respectively. SEM analysis revealed gap sizes for EGMTA, WMTA, EWMTA and GMTA to be (492.3±13.8) µm, (594.5±17.12) µm, (543.1±15.33) µm and (910.7±26.2) µm respectively. A significant difference in gap size between root end preparations filled with GMTA and EGMTA was found (P<0.05). No significance difference in gap size between WMTA and EWMTA were found in either SEM or micro-CT analysis. In conclusion, pre-etching of apical dentin can provide a better seal for GMTA but not for WMTA.
Acid Etching, Dental ; methods ; Aluminum Compounds ; chemistry ; Apicoectomy ; methods ; Calcium Compounds ; chemistry ; Dental Bonding ; Dental Marginal Adaptation ; Dental Pulp Cavity ; ultrastructure ; Dentin ; ultrastructure ; Drug Combinations ; Humans ; Materials Testing ; Microscopy, Electron, Scanning ; Oxides ; chemistry ; Retrograde Obturation ; methods ; Root Canal Filling Materials ; chemistry ; Root Canal Preparation ; instrumentation ; methods ; Silicates ; chemistry ; Surface Properties ; Time Factors ; Tooth Apex ; ultrastructure ; X-Ray Microtomography

OBJECTIVETo observe the influence of different bonding process and three different root canal sealing materials on microstructure of root canal dentin bonding interface after fiber post and resin bonding, so as to improve clinical operation steps and to optimize fiber post resin bonding effect.

METHODSFifteen human single mandibular first premolars were selected. Three were bonded with fiber posts through Relyx Unicem conventional bonding steps after filled with root canal sealing materials of zinc oxide eugenol paste (Group A), and another three were bonded through the same steps after filled with sealing materials of Vitapex (Group B). The other nine were filled with sealing materials of AH Plus, randomly divided into three groups and bonded through different steps as follows: conventional bonding steps only (Group C), etching with 35% phosphoric acid before conventional bonding steps (Group D), and etching and coating with Singlebond 2 adhesive before conventional bonding steps (Group E). After immersed in saline solution for one week, all the roots were cut into three sections of 3 mm in thickness with emery chip and numbered as crown section, middle section and tip section respectively. The samples were observed the resin protrusion in mixed layer of dentin interface and dentinal tubules by scanning electron microscopy.

RESULTSWe observed the resin protrusion in microstructures of the roots bonded through Relyx Unicem after filled with three different root canal sealing materials (Group A, B, C, E): most obvious in the root crown sections, middle in the root middle sections and least in the root tip sections. Differences were observed in roots filled with different sealing materials: little resin protrusion were observed in crown sections only in Group A and B, but large number of resin protrusion were found in crown and middle sections in Group C-E. Compared with Group C, no more resin protrusion were found in Group D. More and elongated resin protrusions were found in Group E.

CONCLUSIONSWe recommend using AH Plus as root canal sealing materials for residual crown and root needed to strengthen by fiber post. It is no need to etch before Relyx Unicem conventional bonding steps. However, coating Singlebond 2 adhesive after acid etching has the potential to increase fiber post cementation.

Acid Etching, Dental ; methods ; Calcium Hydroxide ; Dental Bonding ; methods ; Dental Pulp Cavity ; ultrastructure ; Dentin ; ultrastructure ; Dentin-Bonding Agents ; chemistry ; Epoxy Resins ; Humans ; Mandible ; ultrastructure ; Microscopy, Electron, Scanning ; Molar ; ultrastructure ; Post and Core Technique ; Resin Cements ; Root Canal Filling Materials ; chemistry ; Silicones ; Tooth Root ; ultrastructure ; Zinc Oxide-Eugenol Cement

This study was aimed to assess the stress distribution of different capacity of class I cavity after composite resin filling. A three-dimensional finite element made of the maxillary second molar was constructed by spiral CT scan technology. Based on this model, stress distribution in tooth was analyzed before and after post-core restorations with 5 different capacities of class I cavity. When the circle triangle of class I cavities being under 50N vertical pressures, the cavity capacity increased from 3.3 mm to 3.7 mm, the maximum tensile stress values of the composite resin restorations being 3 times those of normal tooth, which were 14.872 MPa, 16.682 MPa and 17.589 MPa, 17.307 MPa and17.912 MPa. Obviously, the effect of different capacities of class I cavity on the maximum stress value enduring ability of teeth was samll, but in the analysis model, the enduring ability of teeth was reduced when the molars were filled with resin.
Composite Resins ; chemistry ; Computer Simulation ; Dental Stress Analysis ; Finite Element Analysis ; Humans ; Imaging, Three-Dimensional ; Models, Biological ; Molar ; diagnostic imaging ; pathology ; Post and Core Technique ; Root Canal Filling Materials ; chemistry ; Tomography, Spiral Computed

OBJECTIVETo investigate the associated factors that influence the removal of intraradicular resinifying material.

METHODSOne hundred and ninety-seven root canals were treated with resinifying therapy, then the canals were negotiated with sonic, ultrasonic and hand instrument. Those failed to be negotiated were splinted longitudinally and observed with ZOOM-630E stereomicroscope.

RESULTSSonic and ultrasonic instrument negotiated more canals, especially those with jelly-like resinifying material (76.0% approximately 84.0%) and of smaller curvature (90.0% approximately 100.0%) or larger initial apical file (IAF) size (93.8% approximately 100.0%). Those with hard resinifying material and of bigger curvature or smaller IAF size were hard to be negotiated no matter which kind of instrument was used (0 approximately 20%).

CONCLUSIONSVibratory instrument can effectively removal intraradicular resinifying material.

Dental Pulp Cavity ; Dental Pulp Diseases ; therapy ; Humans ; Retreatment ; Root Canal Filling Materials ; chemistry ; Root Canal Therapy ; instrumentation ; methods

Glass ionomer Cement (GIC) is a kind of new dental restorative material. At present, GIC is finding wider use in dental clinical practice such as restoration, adhesion, cavity liner, cure of dental sensitivity and temporary restoration of cavity, because it has several excellent advantages of strong adhesive strength, low stimulation, inhibition of carious teeth. In this paper, the history of glass ionomer cement is introduced and the researching development and perspective of modified glass ionomer cement is elaborated.
Dental Bonding ; Dental Restoration, Permanent ; methods ; Glass Ionomer Cements ; chemistry ; Humans ; Root Canal Filling Materials ; chemistry ; Tensile Strength

OBJECTIVETo evaluate the possibility for removal of resinifying agent, time required for removal and the working length loss by Resosolv or Chloroform.

METHODS40 human teeth (80 root canals) obturated with FR phenolaldehyde agent were divided into four groups, 20 root canals per group. Group A: Resosolv with K file; group B: chloroform with K file; group C: Resosolv with Ultrasonic K file; group D: Chloroform with ultrasonic K file. Calculating the pereentage for removal of resinifying agent, time required for removal and the working length loss.

RESULTSThe effectiveness of Resosolv for removing resinifying agent was better than chloroform. 87.5% of canals could be negotiated by Resosolv; 45% of canals be negotiated by chloroform.

CONCLUSIONResosolv is an effective solvent for canals obturated with resinifying agent.

Chloroform ; chemistry ; Humans ; Retreatment ; Root Canal Filling Materials ; chemistry ; Root Canal Obturation ; methods ; Solvents ; chemistry