OBJECTIVETo investigate the effects of post space preparation and post restoration on apical sealing ability.

METHODS60 extracted mandibular premolars each with single canal were selected. All canals were prepared by manual ProTaper instrument using crown-down technique. The samples were the divided into 5 groups randomly. Group A: 20 samples, the immediate post space preparation group; group B: 20 samples, the delayed post space preparation group; group C: 10 samples, the intact group; group D: 5 samples, a positive control; group E: 5 samples, a negative control. There were two subsets in groups A and B which were restored by temporary materials (A1 and B1) or fiber post and cores (A2 and B2). Indian ink dye method was used to measure the apical leakage in stereomicoscope.

RESULTSThe mean length of dye penetration for group A1, A2, B1, B2 and C were (0.52 +/- 0.47), (0.49 +/- 0.44), (1.17 +/- 0.77), (1.12 +/- 0.54), and (0.23 +/- 0.40) mm, respectively. Positive group demonstrated maximum dye penetration, and negative group showed no dye penetration. There was no statistically significant difference between group A1, A2 and group C (P>0.05). However, there were statistically significant differences between group B and group A, C (P<0.05). The length of dye penetration for group B was longer than that for group A and C.

CONCLUSIONThe sealing ability was decreased after delayed post space preparation when using the AH-Plus sealer.

Dental Leakage ; Humans ; Root Canal Filling Materials ; Root Canal Obturation

Resin composite, which is commonly used as a dental filling material, has some problems, such as poor wear resistance, polymerization shrinkage, and poor dentin marginal adaptability. Preheating of resin composite improves its pro-perties. This paper reviewed the effects of resin composite preheating on its monomer conversion, marginal microleakage, mechanical properties, and irritation on dental pulp.
Composite Resins ; Dental Leakage ; Dental Materials ; Dental Restoration, Permanent ; Materials Testing ; Surface Properties

OBJECTIVETo evaluate the coronal microleakage of teeth restored with fiber posts and composite cores with four different resin bonding systems.

METHODSSixty extracted human maxillary single-rooted teeth were endodontically treated and randomly divided into four groups. Post spaces were prepared in the root canals. Four different resin bonding systems (RelyX Unicem, Dulink, DC core Automix, Luxacore) were used respectively to bond fiber posts and reconstruct cores. The specimens were immersed in India ink for one week. Subsequently all teeth were demineralized, dehydrated and rendered transparent. Then microleakage was observed with stereomicroscope.

RESULTSThe microleakage degrees among four resin bonding systems were significantly different (P = 0.007), and group C showed the least microleakage compared with the other three.

CONCLUSIONSelf-etching resin bonding systems have a super margin sealing ability.

Composite Resins ; Dental Bonding ; Dental Leakage ; Dentin-Bonding Agents ; Humans ; Post and Core Technique ; Resin Cements

OBJECTIVEThe purpose of this study is to study the sealing ability and the furcal appearance of repairing subpulpal wall perforation with resinous inlay.

METHODSFifty newly extracted human molars were randomly divided into three experiment groups (group A, group B, group C, 15 teeth each) and one control group (5 teeth). In experiment groups, perforations were made perpendicularly to the center of the pulp chamber floor. Perforations of group A and B were repaired with resinous inlay and sealed by AH Plus sealer and luting glass-ionomer, respectively. Perforations of group C were directly repaired using light-cure composite resin. Perforations were not made in five teeth of control group. The furcal appearances were evaluated under stereomicroscope after repairing. Microleakage was measured by glucose oxidase detection.

RESULTSThe fineness rate of furcal appearances with resinous inlay repairing were 83.3%, while the fineness rate of furcal appearances with light-cure composite resin directly repairing were 46.7%. There were statistics difference between resinous inlay repairing and light-cure composite resin directly repairing (P<0.05). There were statistics difference among the daily microleakage of three experiment groups, group A

CONCLUSIONUsing resinous inlay to repair the subpulpal wall perforation can improve the sealing effect and avoid material overextension. AH Plus can be used as perforation sealant because of its better sealing ability.

Bicuspid ; Composite Resins ; Dental Leakage ; Dental Pulp Cavity ; Glass Ionomer Cements ; Humans ; Inlays ; Molar

OBJECTIVETo evaluate the marginal adaptation between the new nano-hydroxyapatite composite resin and tooth.

METHODSThirty extracted healthy premolars were randomly assigned to three groups according to the material employed: New nano-hydroxyapatite composite resin (Group A), Karisma composite resin (Group B), and glass ionomer cement (Group C). After the thermal cycling, the teeth were immersed in 2% methylene blue dye, and the depth of microleakage between the composite and tooth structure were observed.

RESULTSThe microleakage depth of group A, B and C were (1.20+/-0.81), (1.94+/-0.70), and (1.73+/-0.54) mm, respectively. No statistically significant differences were found among the three groups (P>0.05). There was no significant difference in the degree of microleakage (P>0.05).

CONCLUSIONAs a new dental restorative material, new nano-hydroxyapatite composite resin has good bonding performance to the tooth structure.

Composite Resins ; Dental Leakage ; Dental Restoration, Permanent ; Durapatite ; Glass Ionomer Cements ; Humans ; Resin Cements

OBJECTIVETo evaluate the effect of internal matrix on sealing ability and furcal appearance of perforations repair with amalgam and resin.

METHODSPerforations created in the pulpal floor of human extracted molars were repaired as follows: Amalgam, amalgam plus calcium sulfate, light-cured resin, and resin plus calcium sulfate (15 teeth/group). The furcal appearance of samples was evaluated under an operating microscope after repair. With the leakage test device, coronal 1 mol/L glucose solution was forced toward the pulpal floor. Leakage was measured by the concentration of leaked glucose in bottom reservoir at 1, 2, 4, 7, 10, 15 and 20 days with enzymatic glucose oxidase method.

RESULTSNo significant difference was found between group 1 and group 2 (P > 0.05). Leakage in group 4 was obviously lower than group 3 (P < 0.05) after the 7th day.

CONCLUSIONCalcium sulfate significantly improved the sealing effect of resin and provided successful barriers against its overextension.

Calcium Sulfate ; Dental Leakage ; Dental Pulp ; Humans ; Molar ; Root Canal Filling Materials ; Tooth Root

OBJECTIVEThe purpose of this study was to compare the quality of apical seal of the canals that obturated with differently tapered gutta-percha cone using continuous wave technique.

METHODS62 extracted human mandible incisors were prepared with Gates-Glidden drill and Hero642 to a final file of No. 30 and 0.06 taper. The teeth were randomly separated into 0.02 taper group (30 teeth), 0.06 taper group (30 teeth) and positive control group (2 teeth). The teeth of 0.02 taper group and 0.06 taper group were respectively obturated with a 0.02, or 0.06 tapered gutta-percha cone and Cortisomol sealer using warm vertical condensation technique separately. The teeth of positive control group were not obturated. In 0.02 taper group and 0.06 taper group, 10 teeth were placed in India ink for 24 hours, 10 teeth were placed in India ink for 10 days, 10 teeth were placed in India ink for 90 hours after 67 days storage in Hank's balanced salt solution. The teeth of positive control group were placed in India ink for 24 hours. The apical leakage was evaluated by the linear measurement under the stereomicroscope.

RESULTSThe dye penetration of positive control group was along the whole canals. The apical leakage of 0.02 taper group increased along with time, while no difference was found among 0.06 taper group. There was a significant difference in the degree of leakage between 0.02 taper group and 0.06 taper group in 67 days (P = 0.041), but not in 24 hours and 10 days groups (P = 0.601, P = 0.471).

CONCLUSIONBetter apical seal was obtained when using the same tapered gutta-percha cone with root canal.

Dental Leakage ; Gutta-Percha ; Humans ; Incisor ; Molar ; Root Canal Obturation ; Zinc Oxide-Eugenol Cement

OBJECTIVETo evaluate the effect of different root canal irrigants and cements on coronal microleakage and the interaction effects after cementing metal post-cores.

METHODSNinety newly extracted single-rooted mandibular human premolars were endodontically treated. Post spaces were prepared in the root canals, and Co-Cr post-cores were cast routinely. The specimens were randomly divided into six groups (n = 15) via a two-way factorial design method. The irrigant factors (A) included A1: no irrigant (75% alcohol wiping), A2: 3% H2O2 + 0.9% NaCl, and A3: 15% ethylenediamine tetraacetic acid (EDTA) + 5.25% NaClO. The cement factors (B) included B1: zinc polycarboxylate cement, and B2: glass ionomer cement. The specimens received treatments based on the grouping of A1B1, A1B2, A2B1, A2B2, A3B1, and A3B2. All samples were sectioned longitudinally after being immersed in India ink for three weeks. The microleakages were observed using a stereomicroscope. The SPSS 13.0 software package was used for factorial analysis.

RESULTSThe mean microleakage scores and standard deviations were as follows: Group A1BI: (1,192.59 +/- 417.84) microm, Group A1B2: (1,317.38 +/- 527.35) microm, Group A2B1: (1,429.33 +/- 482.68) microm, Group A2B2: (1,026.79 +/- 459.49) microm, Group A3B1: (1,448.29 +/- 561.02) microm, and Group A3B2: (1,922.47 +/- 678.86) microm. The A2B2 group showed minimum microleakage, whereas the A3B2 group showed maximum microleakage. The microleakage degrees among different irrigants presented significant statistical difference (P < 0.05), but the two cements showed no significant difference (P > 0.05). An interactive effect on the microleakage existed between the irrigants and the cements after cementing the metal post-cores (P < 0.05).

CONCLUSIONWhen cementing metal post-cores, the coronal microleakage following 3% H2O2 + 0.9% NaCl irrigation combined with glass ionomer cement can be reduced. The combined application of 15% EDTA + 5.25% NaClO and glass ionomer cement significantly aggravates microleakage.

Cementation ; Dental Cements ; Dental Leakage ; Glass Ionomer Cements ; Humans ; Hydrogen Peroxide ; Metals ; Post and Core Technique ; Resin Cements ; Root Canal Irrigants

OBJECTIVETo investigate the influence of sealer placement on apical sealability in root canal treatment.

METHODS100 extracted single root canal teeth were selected. All canals were prepared by manual Protaper instrument in a step-back way. The samples were divided into 5 groups randomly. A group: 30 samples, sealer placement by chief gutta percha; B group: 30 samples, sealer placement by K file; C group: 30 samples, sealer placement by spreader; D group: 5 samples, a positive control; E group: 5 samples, a negative control. There were 2 subsets in each experimental group which were obturated by lateral gutta percha with or without sealer. Glucose oxidase method was used to measure the apical leakage at the 1st 2nd, 4th, 7th, 10th, 15th, 20th, 25th, 30th day of the experiment.

RESULTSApical sealability varied with different sealer placement methods (F=4.832, P=0.001). Sealer placement by chief gutta percha (A group) had the best instant apical sealability. However, lateral gutta percha with or without sealer didn't affect the apical sealibility.

CONCLUSIONPlacing the same kind sealer in different ways can affect the apical sealability. There were no significant differences of the apical leakage no matter the lateral gutta percha with or without sealer. In order to get better instant apical sealability and simplify the clinic operation, placing the sealer with a chief gutta percha while the lateral gutta percha without sealer is recommended.

Dental Leakage ; Dental Pulp Cavity ; Gutta-Percha ; Humans ; Root Canal Obturation ; Root Canal Preparation ; Zinc Oxide-Eugenol Cement

OBJECTIVETo evaluate the effects of a bleaching gel and a whitening strip on the microleakage of three different glass-ionomer cements.

METHODSForty-five freshly extracted human premolars were used and class V cavity was prepared on the buccal and lingual surfaces. The teeth were randomly assigned to A, B and C groups and restored as follows: Conventional strengthen glass-ionomer cement (Ketac Molar Easymix), compomer (F2000) and compomer (Dyract AP). Teeth were kept in distilled water at 37 degrees C for 7 days. Then the specimens were thermocycled for 500 times. Each group was randomly divided into 3 subgroups which were treated for 21 days with one of the following: Whitening strip (14% hydrogen peroxide), bleaching gel (10% carbamide peroxide), or distilled water (control). After bleaching, the teeth were placed in a solution of basic fuchsin dye for 24 hours, then the teeth were sectioned longitudinally to evaluate the dye penetration. The depth of staining along the tooth restoration interface was recorded with a stereomicroscope.

RESULTSThere were no signicant differences between the two bleaching agents in microleakage of restorations (P>0.05). The two bleaching agents did not significantly affect the microleakage of compomer (P>0.05), whereas the microleakage of glass-ionomer cement in the experimental groups was higher than that in the control group (P<0.05).

CONCLUSIONThere are no significant differences in microleakage of restorations between bleaching gel (10% carbamide peroxide) and whitening strip (14% hydrogen peroxide). The two bleaching agents do not significantly affect the microleakage of compomer but adversely affect the microleakage of strengthen glass-ionomer cement.

Bicuspid ; Bleaching Agents ; Compomers ; Composite Resins ; Dental Leakage ; Dental Restoration, Permanent ; Glass Ionomer Cements ; Humans ; Peroxides ; Urea ; analogs & derivatives