OBJECTIVES: This study aims to evaluate the differences in shear bond strength, marginal adaptation, and nano-microleakage after aging among snowplow, layered filling, and lining techniques applied to the resin-bonded restoration of defective primary teeth. METHODS: In this study, 51 freshly extracted, crown-intact primary anterior teeth and 30 primary molars were collected. The experimental groups were as follows: layered filling group, lining group, and snowplow group. Experiments were performed to compare the differences in shear bond strength, marginal integrity, and silver ion nano-microleakage after aging among these groups. RESULTS: The median shear bond strength of the layered filling group, lining group, and snowplow group were 2.45, 5.72, and 9.43 MPa, respectively. The values for lining group and snowplow group were significantly higher than that for layered filling group (P<0.05). No statistically significant difference was found between lining group and snowplow group (P>0.05). The median overall margin integrity of the layered filling group, lining group, and snowplow group were 55.38%, 48.25%, and 65.63%, respectively. The difference among the three groups was not statistically significant (P>0.05). The median percentages of silver ion nano-microleakage in the layered filling group, lining group, and snowplow group were 11.71%, 9.47%, and 11.55%, respectively. The difference among the three groups was not statistically significant (P>0.05). CONCLUSIONS Applying the snowplow technique to restore defective primary teeth can improve the bond strength and margin integrity and reduce nano-microleakage.
Tooth, Deciduous ; Humans ; Dental Restoration, Permanent/methods* ; Dental Leakage ; Shear Strength ; Dental Bonding/methods* ; Molar ; Composite Resins ; Silver

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

OBJECTIVE: To investigate the effect of smear layer on apical sealing ability in teeth obturated with mineral trioxide aggregate (MTA) Plus as retrofilling materials. METHODS: Fifty freshly extracted maxillary anterior teeth or premolars with single root canal were used in this study. All teeth were instrumented to master apical point 60# by using the stepback technique, obturated with lateral condensation technique, and then apical resected. A rootend cavity was then instrumented with an ultrasonic diamond-coated tip. Then the selected teeth were randomly and equally divided into two groups (n=25). In the experimental group (smear-), the teeth were irrigated with 0.17 g/L ethylenediaminetetraacetic acid (EDTA) to remove smear layer on the root-end cavity wall; in the control group (smear+), the teeth were irrigated with physiological saline. Five teeth were extracted to evaluate the cleanliness of root end cavity walls under a videomicroscope, respectively. The scanning electron microscope (SEM) evaluation was also performed for the presence of smear layer and open tubule. For the additional 40 teeth, the root-end cavities were filled with MTA Plus. The quantitative apical leakage of each teeth was evaluated by measuring the concentration of leaked sucrose in apical reservoir on 1, 7, 14, 21, 28, 35, 42, 49 and 56 days, respectively. The samples were stored at 37 °C and 100% humidity for 56 days. Statistical analysis was done with ANOVA for repeated measurement design data. RESULTS: Removal of the smear layer did not cause significantly less apical leaked sucrose than that when the smear layer was left intact for 56 days (P>0.05). There were statistically significant differences at the concentration of leaked sucrose among different observation time points (P<0.05). CONCLUSION It may be concluded that removing the smear layer may not be necessary in root-end cavities filled with MTA Plus.
Aluminum Compounds ; Calcium Compounds ; Dental Leakage ; Drug Combinations ; Edetic Acid ; Oxides ; Root Canal Filling Materials ; Root Canal Irrigants ; Root Canal Preparation ; Root Canal Therapy ; Silicates ; Smear Layer ; Sucrose/pharmacokinetics*

OBJECTIVE: To evaluate the effect of acid etching of retropreps on seal of different retrofill materials. METHODS: In the study, 80 freshly extracted lower molar teeth were used. They were examined under 3.5× magnifying glass to rull out fractures. They were cleaned and stored in distilled water before use. The distal roots were sectioned off and underwent root canal treatment. Rotary nickel-titanium instruments were used during instrumentation and the roots were obturated using lateral condensation technique. The apical portion (3 mm in length) was removed with a fine grit diamond bur, the root tip was retroprepared with a ultrasonic tip (3 mm in depth). The retroprepared roots were randomly assigned to 4 groups and retrofilled with amalgam, intermediate restorative material (IRM), iRoot BP Plus and mineral trioxide aggregate (MTA). The groups were further divided into subgroups according to treatment of the root end cavity (etch and non-etch). The root tips were covered with alginate impression material and were left to set in PBS solution for a week and stained with methylene blue for a week. The roots were removed from the dye solution, thoroughly rinsed and dried, split in halves along the long axis with a diamond disk and observed under a stereoscope. The linear dye leakage was measured and analyzed. One way ANOVA and Tamhane's T2 method were used to analyze the data. The significance level was set at 0.05. RESULTS: The dye leakage results (mean±standard deviation) according to the treatment groups were: amalgam etch (2.80±0.72) mm, amalgam non-etch (2.07±0.86) mm, IRM etch (1.54±0.19) mm, IRM non-etch (1.12±0.28) mm , iRoot BP Plus etch (0.20±0.20) mm, iRoot BP Plus non-etch (0.11±0.08) mm, MTA etch (0.19±0.19) mm, and MTA non-etch (0.17±0.14) mm. One way ANOVA showed significant differences between the groups. Comparison between the groups using Tamhane's T2 method showed roots retrofilled with iRoot BP Plus and MTA had significant less leakage than those retrofilled with amalgam and IRM (P<0.05); There was no significant difference in terms of leakage between iRoot BP Plus and MTA; Acid etching increased leakage of IRM but did not affect MTA, iRoot BP Plus or amalgam retrofillings. CONCLUSION Acid etching is not shown to benefit apical sealing of retrofill materials.
Aluminum Compounds ; Calcium Compounds ; Dental Leakage ; Drug Combinations ; Oxides ; Random Allocation ; Root Canal Filling Materials ; Root Canal Therapy ; Silicates ; Tooth Root

OBJECTIVETo evaluate the influence of different polishing methods on marginal microleakage of zirconium dioxide full crown.

METHODSThirty extracted premolars were selected and randomly divided into three groups, A, B and C, with 10 in each group. Group A was prepared with MANI TF-13 bur completely without the treatment of shoulder. The shoulder of group B was polished with MANI TR13-EF bur after the preparation using MANI TF-13. The shoulder of group C was polished with the dental pneumatic ultrasonic hand-piece of KaVo SONICflex after the preparation using MANI TF-13 bur. Five specimens after preparation were selected in each group. Fifteen CAD/CAM zirconium dioxide full crowns have been made. The crowns were bonded using PULPDENT resin cement, and the root canals were sealed using nail polish, and apical foramen were closed using flow resin. The test-pieces have been immersed in a 3% solution of methylene blue for 24 h. The condition of shoulder marginal microleakage was observed using light stereomicroscopy and evaluated in classification index. The remaining specimens in each group were used for roughness test and scanning electron microscope(SEM) experiment. The marginal microleakage situations of specimens in three groups was analyzed by SPSS 17.0. The enamel surface of different polishing methods was observed using SEM.

RESULTSThe specimens in group C demonstrated the least marginal microleakage, and those in group B showed an intermediate level of marginal microleakage, and those in group A characterized the most serious marginal microleakage (total, χ2=44.610, P<0.01; among the different groups, P<0.05). The roughness experiment showed that specimens in group C achieve the smoothest results ([0.27±0.03] μm). Preparation shoulder polished using the dental pneumatic ultrasonic hand-piece demonstrated the best result under the SEM among the three groups.

CONCLUSIONSThe anti-microleakage effectiveness of dental pneumatic ultrasonic hand-piece in shoulder refinement is better than ordinary shoulder treatment.

Bicuspid ; Computer-Aided Design ; Crowns ; Dental Enamel ; Dental Instruments ; Dental Leakage ; diagnosis ; prevention & control ; Dental Polishing ; methods ; Dental Prosthesis Design ; methods ; Humans ; Pit and Fissure Sealants ; Random Allocation ; Resin Cements ; Ultrasonics ; Zirconium

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 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 furcal perforation treated with iRoot BP.

METHODSForty newly extracted human maxillary and mandibular molars were collected. Holes in diameter of 2 mm were prepared at the roof of the central pulp cavity of 36 samples with high speed round ball diamond in order to make perforated model, and then equally and randomly divided them into two groups. The other intact four samples were used as the negative controls. In the experimental groups, group A were repaired by iRoot BP, group B were repaired by mineral trioxide aggregate(MTA). Three samples in each group were observed under scanning electron microscope(SEM), and microleakage of others was tested by measuring the concentration of leaked glucose with the enzymatic glucose oxidase-peroxidase (GOD-POD) method.

RESULTSMicroleakage of group B was higher than group A and had statistical difference (P<0.05). The dentin and iRoot BP contacted more closely in group A, some gaps existed between the dentin and MTA in group B.

CONCLUSIONFor repairing furcal perforation, the effect of iRoot BP is better than that of MTA.

Aluminum Compounds ; Calcium Compounds ; Dental Leakage ; Dental Pulp Cavity ; Dentin ; Drug Combinations ; Humans ; Molar ; Oxides ; Root Canal Filling Materials ; Silicates ; Tooth Root

OBJECTIVETo evaluate the reliability and superiority of micro-CT in marginal leakage assessment of Class V restorations.

METHODSClass V preparations with gingival margins in dentin and occlusal in enamel were made in sixteen extracted non-carious human molars and restored with dental bonding agents and composite resin. All teeth were then immersed in 50% ammonia-silver nitrate solution for 12 hours, followed by developing solution for 8 hours. Each restoration was scanned by a micro-CT and silver leakage was measured and three-dimensional image of the silver leakage alone cavity wall were reconstructed. Afterward, all restorations were sectioned and examined for leakage depth using a microscope. The silver leakage depth of each restoration obtained by micro-CT and microscope were compared for equivalency.

RESULTSThe silver leakage depths in gingival wall obtained with micro-CT (0.78 mm) and microscope (0.74 mm) showed no significant difference (P > 0.05), while the judgment of leakage depths in occlusal wall in micro-CT image (0.40 mm) was affected by adjacent enamel structure, giving less leakage depths compared to microscope (0.72 mm)(P < 0.01). The three-dimensional shapes of the microleakages displayed clearly by micro-CT alone wall of Class V restorations were multiform and some leakages showed channels on their way to spreading.

CONCLUSIONSMicro-CT can detect precisely the silver leakage in the dentin wall of a restoration and display its three-dimensional shape fully. Enamel structure affects the detection of the silver leakage next to it.

Dental Cavity Preparation ; Dental Enamel ; diagnostic imaging ; pathology ; Dental Leakage ; diagnostic imaging ; pathology ; Dental Restoration, Permanent ; methods ; Humans ; Imaging, Three-Dimensional ; Microscopy ; Molar, Third ; diagnostic imaging ; pathology ; X-Ray Microtomography ; methods

OBJECTIVETo evaluate the microleakage of fiber post and core systems after high-speed handpiece preparation at different time points.

METHODSThe crowns of forty-five extracted human premolar were removed and the roots were endodontically treated. The samples were devided into five groups. Root canal preparation was performed on each premolar followed by fiber post cementation and core build up. Tooth preparation was applied at 5 min in group 1, at 15 min in group 2 and at 30 min in group 3 after post cementation. Five teeth with only 5 mm apical sealing were served as a positive control group, and ten with fiber post and core build-up but no coronal preparation were taken as a negative control group. Microleakage was evaluated using a fluid filtration system. The bonding interface was observed by scanning electronic microscope (SEM).

RESULTSThe microleakage was significantly increased after coronal preparation with high-speed handpiece. The negative control group has less leakage [(1.50 × 10(-6) ± 0.37 × 10(-6)) µl×min(-1)×Pa(-1)] than the groups with coronal preparation (P < 0.05); Group 1 leaked significantly more [(6.02 × 10(-5) ± 1.02 × 10(-5)) µl×min(-1)×Pa(-1)] than group 2 [(1.50 × 10(-5) ± 0.26 × 10(-5)) µl·min(-1)×Pa(-1)] and group 3 [(1.50 × 10(-5) ± 0.39 × 10(-5)) µl×min(-1)×Pa(-1)] did (P < 0.05). Corresponding to microleakage, the micro gaps between the resin cement and dentine in group 1 were wider than those in the other groups. The coronal section was wider than the apical part.

CONCLUSIONSHigh-speed handpiece had negative effects on microleakage of fiber post and core systems. Coronal preparation should be performed 15 min or more after post cementation.

Cementation ; Dental Bonding ; Dental Leakage ; Dentin-Bonding Agents ; Humans ; Microscopy, Electron, Scanning ; Post and Core Technique ; instrumentation ; Resin Cements ; Root Canal Preparation ; Time Factors