Sealing Carious Fissures with Resin Infiltrant in Association with a Flowable Composite Reduces Immediate Microleakage?

Abstract Objective: To compare the immediate microleakage of carious fissures sealed with a caries infiltrant covered by a flowable composite or solely with a flowable composite. Material and Methods: Extracted carious molars (n=20) were selected and paired among the experimental groups according to caries progression scores. Experimental groups (n=10) were divided according to the following sealing techniques: 1) caries infiltrant (Icon) + flowable composite (Z350 flow); 2) flowable composite (Z350 flow). Specimens were immersed in 3% methylene blue and evaluated in a stereomicroscope. Microleakage scores were attributed independently by two calibrated evaluators and the mode value was considered as the mean for the specimen. Binomial tests were used to test differences between two independent sample proportions at 5% significance level. Results: In the flowable composite group, a higher prevalence of dye penetration along the full depth of the fissure was observed, compared with caries infiltrant + flowable composite (p<0.05). For specimens showing dye penetration up to half of the fissure, in caries infiltrant + flowable composite group, all specimens showed dye penetration into the sealant, but not over the infiltrant. Conclusion: Using caries infiltrant as sealing material under a flowable composite cover is effective to improve the immediate sealing ability in carious fissures compared to sealing with flowable composite.

Effect of Qmix and Other Irrigants on Dentin Adhesives in Pulp Chambers of Primary Teeth: SEM Study.

OBJECTIVE: To compare the effect of different endodontic irrigants on microleakage of adhesives used within pulp chamber of primary molars. STUDY DESIGN: 72 Primary molars were divided into 6 groups, according to 3 irrigants and 2 adhesives used. After de-roofing the pulp chamber, pulp was extirpated. In 36 samples, pulp chambers were bonded with Xeno V+ after irrigation with either QMix (Group1); 17%EDTA+5%NaOCl (Group2) or normal saline (Group3) and in other half samples, pulp chambers were bonded with SinglebondUniversal after irrigation with either QMix (Group 4); 17%EDTA+5% NaOCl (Group5) or normal saline (Group 6). All the samples were restored with Filtek Z350. Ten teeth from each group were assessed for dye penetration. Two samples in each group were viewed under scanning electron microscope. Data was statistically analyzed using Mann-Whitney and Kruskal Wallis tests at a significance level of P < 0.05. RESULTS: Mean microleakage scores were: Group 1-1.5±0.70, Group 2-1.6±.51, Group 3-2.4±0.96, Group 4-1.2±0.42, Group 5-1.2±0.42, Group 6-1.1±0.32. CONCLUSIONS: Irrigation with QMix significantly reduced the microleakage of XenoV+ but had no significant effect on microleakage of SinglebondUniversal. Irrigation with EDTA/NaOCl or QMix had no detrimental effect on the sealing ability of either of the adhesive tested.

Oral Function Improves Interfacial Integrity and Sealing Ability Between Conventional Glass Ionomer Cements and Dentin.

The aim of this study was to investigate if load cycling affects interfacial integrity of glass ionomer cements bonded to sound- or caries-affected dentin. A conventional glass ionomer, Ketac Bond, and a resin-modified glass ionomer (Vitrebond Plus), were applied to dentin. Half of the specimens were load cycled. The interfaces were submitted to dye-assisted confocal microscopy evaluation. The unloaded specimens of sound and carious dentin were deficiently hybridized when Ketac Bond was used. Ketac Bond samples showed an absorption layer and an adhesive layer that were scarcely affected by fluorescein penetration (nanoleakage), in sound dentin. Nevertheless, a higher degree of micropermeability was found in carious dentin. In Ketac Bond specimens, load cycling improves the sealing capability and remineralization at the cement-dentin interface as porosity and nanoleakage was reduced. In contrast, samples treated with Vitrebond Plus exhibited a Rhodamine B-labeled absorption layer with scarce nanoleakage in both sound and carious unloaded dentin. The adhesive layer was affected by dye sorption throughout the porous cement-dentin interface. Samples treated with Vitrebond Plus had significant increases in nanoleakage and cement-dye sorption after load cycling. Within the limitations of an in vitro study, it is expected that conventional glass ionomers will provide major clinical efficacy when applied to carious-affected or sound dentin.

A comparative microleakage evaluation of three different base materials in Class I cavity in deciduous molars in sandwich technique using dye penetration and dentin surface interface by scanning electron microscope.

INTRODUCTION: A major objective in restorative dentistry is the control of marginal leakage, which may occur because of dimensional changes or lack of adaptation of restorative material to the cavity preparation. Numerous techniques have been advocated to overcome polymerization shrinkage in composite restorations. AIM AND OBJECTIVES: This study investigated microleakage of three different bases under composite resin in sandwich technique using dye penetration and dentin surface interface using scanning electron microscope (SEM). MATERIALS AND METHODS: Sixty extracted deciduous molars were stored in distilled water and Class I cavities with a width of about one-fourth of intercuspal distance and a depth of 0.5-1 mm below the dentino-enamel junction was prepared without bevels. In Group 1 - glass ionomer cement (GIC); Group 2 - mineral trioxide aggregate (MTA); Group 3 - Biodentine™ was placed as a base under composite. Teeth were longitudinally sectioned in two halves, through the centers of the restoration, immersed in 2% methylene blue and microleakage was evaluated under stereomicroscope and surface interface between base and dentin was evaluated under SEM. RESULTS: Under the condition of in vitro study, less microleakage and less internal gaps were seen in Biodentine™ (0.00 ± 0.00 and 4.00 ± 1.59) group than MTA (0.00 ± 0.00 and 6.08 ± 1.82) and GIC (25.25 ± 6.57 and 14.73 ± 3.72, respectively) and showed very strong positive correlation between microleakage and internal gaps. CONCLUSION: Biodentine™ exhibits superior marginal sealing ability as well as marginal adaptation under composite resin as compared to MTA and GIC.

Evaluation of microleakage in class V composite restorations using dye penetration and micro-CT.

OBJECTIVES: The aim of this study was the evaluation of microleakage in class V cavities using micro-CT imaging and dye penetration. MATERIALS AND METHODS: Sixty class V cavities were prepared, randomly divided into five groups (Adper Single Bond Plus (ASB), ExciTE (EX), iBond TE (ITE), Optibond Solo Plus (OSP), Prime & Bond NT (PB)) and restored with Venus Diamond. After thermocycling and dye penetration test with 50 wt% ammoniacal silver nitrate, eight samples per group were sectioned longitudinally and evaluated under a coaxial incident light microscope (enamel (E) and dentin (D) measurement in mm). The remaining samples were analyzed by counting voids in the coronal and cervical adhesive areas by means of micro-CT. RESULTS: In dentin, no statistically significant difference in dye penetration was found. In enamel, OSP showed significant higher microleakage than all other adhesives (p < 0.001). Groups ITE, ASB, PB, and EX showed a significantly lower penetration depth in E than in D (p < 0.001). The results of the micro-CT examination in dentin are contrary to the findings of the microleakage evaluation. Regarding enamel, only group PB showed significant more voids than EX in enamel (p < 0.02). Within the adhesive groups, PB showed significantly more voids in E than in D (p < 0.04). CONCLUSIONS: This test method must be optimized by developing a new leakage tracer for a better differentiation between hard tissues and dental materials. CLINICAL RELEVANCE: The micro-CT is not yet a vulnerable tool to evaluate the marginal integrity of resin composites.

Non-destructive evaluation of an internal adaptation of resin composite restoration with swept-source optical coherence tomography and micro-CT.

Swept-source optical coherence tomography (SS-OCT) and micro-CT can be useful non-destructive methods for evaluating internal adaptation. There is no comparative study evaluating the two methods in the assessment of internal adaptation in composite restoration. The purpose of this study was to compare internal adaptation measurements of SS-OCT and micro-CT. Two cylindrical cavities were created on the labial surface of twelve bovine incisors. The 24 cavities were randomly assigned to four groups of dentin adhesives: (1) three-step etch-and-rinse adhesive, (2) two-step etch-and-rinse adhesive, (3) two-step self-etch adhesive, and (4) one-step self-etch adhesive. After application, the cavities were filled with resin composite. All restorations underwent a thermocycling challenge, and then, eight SS-OCT images were taken using a Santec OCT-2000™ (Santec Co., Komaki, Japan). The internal adaptation was also evaluated using micro-CT (Skyscan, Aartselaar, Belgium). The image analysis was used to calculate the percentage of defective spot (%DS) and compare the results. The groups were compared using one-way ANOVA with Duncan analysis at the 95% significance level. The SS-OCT and micro-CT measurements were compared with a paired t-test, and the relationship was analyzed using a Pearson correlation test at the 95% significance level. The %DS results showed that Group 3≤Group 4

In-Vitro Comparison Of Micro-Leakage Between Nanocomposite And Microhybrid Composite In Class V Cavities Treated With The Self-Etch Technique.

BACKGROUND: When a light cure composite resin is used to restore a class V lesion, certain stresses are generated at the tooth-restoration interface. If these stresses exceed the bond strength of the restorative material, microscopic gaps are formed which eventually cause micro-leakage at the tooth-restoration interface. The objective of the present study was to compare the micro-leakage values at the tooth-restoration interface using dye penetration method between a Nano filled and a Micro hybrid light cured composite resin in class V cavities using the self-etch technique. METHODS: Sixty class V cavities were made coronal to the cemento-enamel junction in the extracted premolars. These were then randomly divided into two study groups. Group A: Self-etch; filled with P-60 (microhybrid) n=30. Group B: Self-etch; filled with Z-350 (nano-filled) n=30. Specimens were subjected to thermo-cycling at 5-55 °C±2 °C with a 30 seconds dwell time. After which they were stained with 2% methylene blue. Later, sectioned bucco-lingually and examined using a stereo microscope (magnification X4) at the occlusal, axial and gingival surfaces. Micro-leakage around the toothrestoration interface was assessed by using the degree of dye penetration in millimetres. RESULTS: There was 100% micro leakage seen at both the occlusal and gingival surfaces when using the P-60 composite. With the Z-350 composite 84% occlusal and 88% of the gingival surfaces exhibited microleakage.. CONCLUSIONS: With respect to micro-leakage in class V cavities, Z-350 was found to be a superior restorative material compared to P-60 on the occlusal surface. Overall, there is no statistically significant difference in the micro-leakage exhibited by the two restorative materials in class V preparations subjected to self-etch protocol.

The use of micro-CT with image segmentation to quantify leakage in dental restorations.

OBJECTIVE: To develop a method for quantifying leakage in composite resin restorations after curing, using non-destructive X-ray micro-computed tomography (micro-CT) and image segmentation. METHODS: Class-I cavity preparations were made in 20 human third molars, which were divided into 2 groups. Group I was restored with Z100 and Group II with Filtek LS. Micro-CT scans were taken for both groups before and after they were submerged in silver nitrate solution (AgNO3 50%) to reveal any interfacial gap and leakage at the tooth restoration interface. Image segmentation was carried out by first performing image correlation to align the before- and after-treatment images and then by image subtraction to isolate the silver nitrate penetrant for precise volume calculation. Two-tailed Student's t-test was used to analyze the results, with the level of significance set at p<0.05. RESULTS: All samples from Group I showed silver nitrate penetration with a mean volume of 1.3 ± 0.7mm(3). In Group II, only 2 out of the 10 restorations displayed infiltration along the interface, giving a mean volume of 0.3 ± 0.3mm(3). The difference between the two groups was statistically significant (p<0.05). The infiltration showed non-uniform patterns within the interface. SIGNIFICANCE: We have developed a method to quantify the volume of leakage using non-destructive micro-CT, silver nitrate infiltration and image segmentation. Our results confirmed that substantial leakage could occur in composite restorations that have imperfections in the adhesive layer or interfacial debonding through polymerization shrinkage. For the restorative systems investigated in this study, this occurred mostly at the interface between the adhesive system and the tooth structure.

Marginal Leakage of Class V Composite Restorations Assessed Using Microcomputed Tomography and Scanning Electron Microscope.

OBJECTIVE: The aim of the study was to compare in Class V composite restorations marginal leakage measurements obtained with microcomputed tomography (micro-CT) and scanning electron microscopy (SEM) observations. METHODS: Class V cavities were prepared on 10 human molars and restored using Optibond FL (Kerr, Orange, CA, USA) and Premise Flowable (Kerr). Sealing ability was evaluated by assessing silver-nitrate penetration depth along enamel and dentin margins. Leakage was quantified using a scoring system. Micro-CT analysis provided 502 cross-sectional images for each tooth. Microleakage evaluation was performed first on three cross-sections corresponding to the sections examined by SEM, then on all 502 of the obtained micro-CT images. SEM observations were performed first at 20× magnification, then, if showing a zero score, at 80× magnification. Enamel and dentin microleakage scores assigned to corresponding sections through micro-CT and SEM (20×) were compared (Wilcoxon signed-rank test, α=0.05). RESULTS: No statistically significant difference in leakage scores emerged between micro-CT and 20×-magnification SEM. Eight tooth sections that were given a zero score under SEM at 20× magnification showed to be infiltrated at the higher magnification (80×). For five teeth a higher score was assigned following scanning of 502 cross-sections than based on the observation of three sections. CONCLUSIONS: Micro-CT presents as a valid, nondestructive in vitro method to quantitatively evaluate marginal leakage of adhesive restorations.

Application of microcomputed tomography for quantitative analysis of dental root canal obturations.

INTRODUCTION: The aim of the study was to apply microcomputed tomography to quantitative evaluation of voids and to test any specific location of voids in tooth's root canal obturations. MATERIALS AND METHODS: Twenty root canals were prepared and obturated with gutta-percha and Tubli-Seal sealer using the thermoplastic compaction method (System B+Obtura II). Roots were scanned and three-dimensional visualization was obtained. The volume and Feret's diameter of I-voids (at the filling/dentine interface) and S-voids (surrounded by filling material) were measured. RESULTS: The results revealed that none of the scanned root canal fillings were void-free. For I-voids, the volume fraction was significantly larger, but their number was lower (P=0.0007), than for S-voids. Both types of voids occurred in characteristic regions (P<0.001). I-voids occurred mainly in the apical third, while S-voids in the coronal third of the canal filling. CONCLUSIONS: Within the limitations of this study, our results indicate that microtomography, with proposed semi-automatic algorithm, is a useful tools for three-dimensional quantitative evaluation of dental root canal fillings. In canals filled with thermoplastic gutta-percha and Tubli-Seal, voids at the interface between the filling and canal dentine deserve special attention due to of their periapical location, which might promote apical microleakage. Further studies might help to elucidate the clinical relevance of these results.

Detection of marginal leakage of Class V restorations in vitro by micro-computed tomography.

This in vitro study evaluated the efficacy of micro-computed tomography (CT) in marginal leakage detection of Class V restorations. Standardized Class V preparations with cervical margins in dentin and occlusal margins in enamel were made in 20 extracted human molars and restored with dental bonding agents and resin composite. All teeth were then immersed in 50% ammoniacal silver nitrate solution for 12 hours, followed by a developing solution for eight hours. Each restoration was scanned by micro-CT, the depth of marginal silver leakage in the central scanning section was measured, and the three-dimensional images of the silver leakage around each restoration were reconstructed. Afterward, all restorations were cut through the center and examined for leakage depth using a microscope. The silver leakage depth of each restoration obtained by the micro-CT and the microscope were compared for equivalency. The silver leakage depth in cervical walls observed by micro-CT and microscope showed no significant difference; however, in certain cases the judgment of leakage depth in the occlusal wall in micro-CT image was affected by adjacent enamel structure, providing less leakage depth than was observed with the microscope (p<0.01). Micro-CT displayed the three-dimensional image of the leakage around the Class V restorations with clear borders only in the dentin region. It can be concluded that micro-CT can detect nondestructively the leakage around a resin composite restoration in two and three dimensions, with accuracy comparable to that of the conventional microscope method in the dentin region but with inferior accuracy in the enamel region.

[Detection of marginal leakage of Class V restorations in vitro by micro-CT].

OBJECTIVE: To evaluate the reliability and superiority of micro-CT in marginal leakage assessment of Class V restorations. METHODS: Class 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. RESULTS: The 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. CONCLUSIONS: Micro-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.

Marginal leakage of two newer glass-ionomer-based sealant materials assessed using micro-CT.

OBJECTIVES: To test newer glass-ionomer-based materials as sealant materials. One glass-ionomer sealant was light-cured to obtain an early setting reaction. The null-hypothesis tested was: there is no difference in marginal leakage of sealants produced with high-viscosity glass-ionomer, with and without energy supplied, and that of glass-carbomer, in comparison with resin composite sealants in vitro. METHODS: Materials used were Clinpro, Ketac Molar Easymix and Glass-Carbomer. Sealants were placed in the occlusal surface of 89 molar teeth, thermocycled for 5000 cycles and evaluated using micro-CT for silver nitrate penetration depth at the enamel-sealant interface by two trained evaluators. Data were analysed, using ANOVA and Scheffe's test. RESULTS: Glass-carbomer sealants showed one or more 'fracture lines' in the material and at the enamel-material interface, filled with a kind of transparent, but not black coloured, material. High-viscosity glass-ionomer sealants with and without energy supplied had statistically significantly lower mean marginal leakage scores than sealants produced by composite resin (p<0.01). No marginal leakage was found in the high-viscosity glass-ionomer group without energy supplied. CONCLUSIONS: The high-viscosity glass-ionomer (Ketac Molar Easymix) sealants had lower marginal leakage than resin composite sealants, and should be tested in vivo. Glass-carbomer sealants were non-interpretable.

A novel approach in assessment of coronal leakage of intraorifice barriers: a saliva leakage and micro-computed tomographic evaluation.

The efficacy of amalgam, Fuji-Plus, Geristore, and mineral trioxide aggregate (MTA) as intraorifice barriers was compared in a simulated saliva leakage model. Fifty teeth were divided into 4 experimental (n = 10 each) and 2 control groups (n = 5 each). Two millimeters of the materials was placed as intraorifice barriers and brought into contact with human saliva in a coronal reservoir. Bacterial leakage into the apical reservoir was assessed daily for 3 months. Geristore barriers leaked significantly more often (5/10) than Fuji-Plus (0/10, P < .05) at 60 days. The first Fuji-Plus sample leaked after 70 days; after 90 days, 3 (Fuji-Plus), 4 (MTA, amalgam), and 6 (Geristore) samples leaked. There were no significant differences between the experimental groups at that time point. Three-dimensional gap volumes in the barrier-dentin interface and the porosity of the barrier materials were compared by using micro-computed tomography (microCT). A measurable gap was evident in only 1 specimen with an MTA barrier. MTA was significantly less porous than Fuji-Plus and Geristore (P < or = .05), whereas amalgam was too radiopaque to allow microCT measurements. In conclusion, Fuji-Plus might be an effective intraorifice barrier (up to 70 days in vitro), but all 4 materials showed leakage in some specimens at 90 days.

Bacterial leakage in root canals obturated by different techniques. Part 1: microbiologic evaluation.

OBJECTIVE: This study compared the coronal bacterial leakage of root canals obturated by different techniques and with different lengths of obturation. STUDY DESIGN: The canals of palatal roots of 160 maxillary molars were instrumented and divided into different groups according to the obturation technique used (lateral condensation, Microseal system, Touch 'n Heat + Ultrafil system, or Tagger's hybrid technique) and the length of obturation (5 mm or 10 mm). The roots were impermeabilized, sterilized in ethylene oxide, and mounted on a device for evaluation of the bacterial leakage. RESULTS: Tagger's hybrid technique produced a statistically greater number of specimens with coronal leakage than the other techniques. There was no statistically significant difference between the lateral condensation, Touch 'n Heat + Ultrafil, and Microseal groups. Root canals with 10 mm of obturation produced a statistically significantly smaller number of specimens with leakage than root canals with 5 mm of obturation. CONCLUSION: Tagger's hybrid technique produced a greater number of specimens with coronal leakage than the other techniques, and a greater number of root canals with 5 mm of obturation leaked than root canals with 10 mm of obturation.

Micro-CT for measuring marginal leakage of Class II resin composite restorations in primary molars prepared in vivo.

PURPOSE: To evaluate the reliability of marginal leakage assessment of self-etch adhesive Class II resin composite restorations in primary molars prepared in vivo using the micro-CT. METHODS: Fourteen primary molars, divided over seven ART and seven traditional resin composite Class II restorations, were subjected to marginal leakage test using a 50% (w/v) silver nitrate solution for 4 hours by a micro-CT. Two evaluators selected the image with the deepest marginal dye penetration for each restoration from the occlusal and approximal surfaces on consensus. The deepest dye penetration depth and total length of the axial cavity wall from both the occlusal and from the approximl surface were measured manually using morphometric quantification software by three evaluators independently. ANOVA was applied to test for differences in marginal leakage scores between the three evaluators. RESULTS: There was no marginal leakage found in five traditional and one ART restoration. The percentage of silver nitrate penetration depth from the cervical-approximal site ranged from 10.2-92.6%. There was only a statistically significant difference observed in measuring total axial wall length from the cervical-approximal site between the three evaluators (P = 0.02). This explanatory investigation showed that the micro-CT was a very useful device for developing a standardized method for measuring marginal leakage from samples obtained in vivo. In combination with 50% (w/v) silver nitrate and 4-hour immersion, marginal leakage along the restoration-tooth tissue interface was accurately and reliably measured. (Am J Dent 2008;21:393-397).

The sealing ability of GuttaFlow in oval-shaped canals: an ex vivo study using a polymicrobial leakage model.

AIM: To compare systematically the sealing ability provided by four endodontic cements: AH Plus, Pulp Canal Sealer EWT, RoekoSeal and GuttaFlow. METHODOLOGY: A sample of 100 human mandibular incisors with oval-shaped canals was selected from an initial sampling of two hundred teeth. The root canals in 80 teeth were prepared and filled by the same operator using the cold lateral compaction technique with one of the following four cements (n = 20): G1: AH Plus; G2: Pulp Canal Sealer EWT; G3: RoekoSeal and G4: GuttaFlow. Ten teeth with intact crowns served as negative controls and 10 teeth that were not root filled served as positive controls. All teeth were mounted in a two chamber apparatus and then exposed to human saliva. The number of days over a 9-weeks-period was recorded for the appearance of turbidity in the BHI broth. A Log-rank test was used to analyse the leakage data. RESULTS: Overall, 30% of the samples of the AH Plus group (G1) and 35% of the Pulp Canal Sealer EWT group (G2) were fully contaminated after 9 weeks, whereas 15% of RoekoSeal (G3) and GuttaFlow (G4) groups were fully contaminated. There was a significant difference between (G1/G2) and (G3/G4) (P < 0.05). There was no significant difference between G1 and G2 or between G3 and G4 (P > 0.05). CONCLUSION: The silicone-based sealers revealed the best results throughout the experimental period. Leakage patterns of AH plus and Pulp Canal Sealer were statistically similar.

Microleakage study of 3 porcelain repair materials by autoradiography.

OBJECTIVE: The purpose of this investigation was to test the microleakage of 3 porcelain repair systems intended for intraoral resin-to-porcelain and resin-to-metal bonding by autoradiography. METHOD AND MATERIALS: Sixty alloy and 60 porcelain disks (10-mm diameter and 2-mm thickness) were prepared. Manufacturer's directions were followed for surface treatment of specimens. Each repair material was applied on 20 alloy specimens and 20 porcelain specimens. Specimens were thermocycled by dipping them in water for 1 minute at 4 +/- 2 degrees C and 58 +/- 2 degrees C for 500 cycles. Leakage was demonstrated by the presence of radioactive isotope at the interface between the repair material and the alloy (or porcelain) as registered by autoradiography. Before testing, specimens were stored in distilled water at 37 degrees C for 24 hours and then thermocycled. Mann-Whitney U test was used to identify the differences. RESULTS: For the alloy groups, differences between Newbond/Clearfil Lustre and GoldLink 2/Ultrabond were significant (P <.05). For the ceramic groups, differences between Cerinate Prime/Ultrabond, Clearfil Lustre/Newbond, Cerinate Prime/Ultrabond, and Silibond/Charizma were significant (P <.05). CONCLUSIONS: For the porcelain groups, the amount of microleakage in Ultrabond/Cerinate Prime was significantly higher than the other groups. For the alloy groups, all samples showed leakage.

An evaluation of the quality of root fillings in mandibular incisors and maxillary and mandibular canines using different methodologies.

OBJECTIVES: To evaluate the quality of root fillings in mandibular incisors and maxillary and mandibular canines using different methodologies of evaluation, namely radiographs, the fluid transport test and the percentage of gutta-percha (PGP), and to determine if a correlation occurs between the results of the different methodologies used. METHODS: One group of mandibular incisors with oval canals (n=20) and one group of maxillary and mandibular canines (n=20) were instrumented and obturated by cold lateral compaction using AH 26 as the sealer. The filled roots were bucco-lingually and mesio-distally radiographed. Using a scoring system, the quality of each root filling was radiographically evaluated, the higher the score the poorer the quality. Fluid transport along the root filling was then measured using a fluid transportation device. Each root was horizontally sectioned 4 and 6mm from the apex. Images of the cross-sections were taken, using a microscope and a digital camera. Images were scanned into a PC as TIFF images. Using a KS 100 Imaging system the canal area and the gutta-percha filled areas were measured. The percentage of gutta-percha filled areas was calculated. RESULTS: Considering the radiographic scores of the two different projections together the score was significantly higher for the mandibular incisors than for the canines (P=0.039). The radiographic score was significantly higher for the mesio-distal radiograph in comparison with the bucco-lingual radiograph (P=0.0001), for the canines as well as the incisors. Using only the bucco-lingual radiograph there was no significant difference between the mandibular incisors and the canines (P=0.992). The mandibular incisors displayed significantly more fluid transport than the canines (P=0.049). A significantly greater percentage of gutta-percha filled areas was found in the cross-sections of canines as compared to the cross-sections of mandibular incisors (P=0.000001). The correlation between the radiographic score of the mesio-distal radiograph and the PGP 4 and 6mm was significant (P=0.013). There was no significant correlation between the FT and the radiograph or the FT and the PGP. CONCLUSIONS: The quality of the root fillings in oval canal-mandibular incisors may be compromised.

Evaluation of adhesive defects using an ultrasonic pulse-reflection technique.

The purpose of this study was to examine the application of an ultrasonic pulse-reflection technique for the evaluation of adhesive defects. First, the sonic velocities in the enamel and dentin of human molars and bovine incisors were measured with a pulsar receiver attached to an ultrasonic transducer. The identification of the dentino-enamel junction and pulp-dentin interface using the ultrasonic method based on intrinsic sonic velocities showed good agreement with the actual measured thicknesses. Next, a cemented restoration with artificial faults was prepared. Half of the Au-Ag-Pd alloy plate area was cemented to the dentin slab using luting resin cement. The adhesive interface was evaluated with a high-resolution ultrasonic imaging system. Clear internal faults were evident from the ultrasonic tomogram. The findings of this study suggest that the ultrasonic pulse-reflection technique may be useful for inspecting and imaging structural defects of adhesive interfaces.