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The aim of this study was to evaluate the microleakage of direct and indirect composite inlays by stereomicroscopy and scanning electron microscopy (SEM). Thirty bovine incisors were ground to obtain an incisal platform, simulating the occlusal surface of a human molar. Each tooth received two 8 degrees proximal cavities with cervical finishing line prepared in dentine or enamel. One of the cavities was filled with Filtek Z250/Single Bond, using the direct technique, and the other was filled with with Solidex/Rely X ARC/Single Bond, using the indirect technique. The samples were stored in water at 37 degrees C for 24 hours and placed in a 50% silver nitrate solution for 6 hours in a dark container. Next, the samples were washed under running water, immersed in a developing solution and exposed to fluorescent light for 12 hours. The teeth were then severed and evaluated for dye penetration by stereomicroscopy and SEM. There were no significant differences between the direct and indirect techniques for the cervical finishing line in enamel, but for the finishing line in dentin, the indirect technique allowed less microleakage than the direct technique. SEM analysis showed leakage similar to that observed by stereomicroscopic analysis. The use of stereomicroscopic and SEM evaluations improves microleakage analysis.

This in vitro study compared the microleakage of Class V resin composite restorations at bevelled enamel/composite and dentin/composite interfaces following Er:YAG laser (pre-treatment modalities: laser-etching and/or acid-etching) or conventional preparation and acid-etch, in association with two resin composite formulations and their three-step adhesive system. Class V cavities with conventional bevel produced on the lingual and buccal surfaces of eighty extracted caries- and restoration-free human teeth, were assigned to eight groups: cavities were or Er:YAG-lased and acid-etched (groups 1 and 5); or Er:YAG-lased, laser-etched and acid-etched (groups 2 and 6); or Er:YAG-lased and only laser-etched (groups 3 and 7); or cut by dental drill at high-speed and acid-etched (groups 4 and 8). The specimens were restored with Optibond FL+Herculite XRV (groups 1, 2, 3 and 4) or with Scotchbond MP+Z 100 (groups 5, 6, 7 and 8), stored in distilled water at 37 degrees C for 24 h, thermocycled 1500 times between 5 and 55 degrees C, placed in a 2% aqueous solution of methylene blue for 24 h at 37 degrees C, embedded in resin and sectioned. Microleakage was assessed according to the depth of dye penetration along the restoration. There were statistically significant differences between occlusal and cervical regions for all groups (P<0.01) except for groups 3 and 7. Pair-wise comparison of groups showed that acid-etch is advocated when using resin composite in Er:YAG-lased Class V cavities; the seal at enamel margins in Er:YAG-lased and laser-etched cavities depended on the resin composite formulation and corresponding adhesive (P<0.05).

The aim of this study was to evaluate the ability of three obturation methods to seal root canals prepared using 0.06 taper rotary instruments. Forty-five extracted human single-rooted teeth were instrumented with 0.06 taper Profile nickel-titanium rotary files and randomly divided into three experimental groups containing 15 teeth each. The first group was obturated using the System B technique with 0.06 taper standardised gutta-percha points, the second group was obturated using the System B technique with non-standardised MF gutta-percha points, the third group was obturated by cold lateral condensation technique using standardised 0.02 taper master gutta-percha points. Apical leakage of the roots was evaluated by dye penetration using a stereomicroscope after sectioning the roots. The group obturated using System B and 0.06 taper gutta-percha points showed the least dye penetration. However, the difference in the linear extent of dye penetration was not statistically significant.

The aim of this study was to compare the in vitro sealing ability of ProRoot MTA, ProRoot MTA (Tooth-Coloured Formula), ordinary Portland cement and white Portland cement when used as root-end filling materials. Twenty-four single-rooted human premolars were prepared and obturated using standard techniques, then retrofilled with the test materials. The prepared teeth were immersed in 1% methylene blue dye for 72 hours and then assessed for dye leakage. The depth of dye penetration was measured and expressed as a percentage of the length of the retrofilling. Data was analysed using ANOVA and Fisher's Least Significant Test (LSD) (p < 0.05). None of the teeth in any of the test groups showed leakage beyond the retrofillings. Given the low cost and apparently similar sealing ability of the cements, it is reasonable to consider Portland cement as a possible substitute for MTA as a root-end filling material. However, further tests, especially in vivo biocompatibility tests, need to be conducted before Portland cement can be recommended for clinical use.

Background and Objective: This study aimed to evaluate the extent of microleakage in cavities prepared with bur and Er:YAG laser, hybridized with different bonding systems., Study Design: Sixty bovine teeth were randomly divided into six groups (n = 10): (G1) Diamond bur + Single Bond; (G2) Diamond bur + AdheSE; (G3) Diamond bur + Clearfil SE Bond; (G4) Er:YAG (250 mJ, 4 Hz, 80.6 J/cm(2)) + Single Bond; (G5)Er:YAG + AdheSE, and (G6) Er:YAG + Clearfil. Cavities were restored with a micro-hybrid composite resin. After thermocycling, the specimens were stained with 2% methylene blue solution and sectioned in the mesiodistal direction. Dye penetration was scored based upon the extent of the dye using a light stereoscope., Results: The Kruskal-Wallis and Mann-Whitney test revealed no statistically significant differences between the method of preparation (diamond bur and laser). However, statistical differences were found between the adhesives tested., Conclusion: Based on the results of this study, Er:YAG laser confirmed to be as effective as the conventional methods for preparing adhesive restorations., ((c) 2005 Wiley-Liss, Inc.)

To determine the effect of Light emitting diode (LED) curing on dental resins, microleakage, shear bond strength and surface hardness of a dental composite cured with different LEDs were determined and compared with conventional halogen curing. For microleakage, Class V cavities were restored with Esthet-X, divided into groups, and exposed to one of the curing protocols (Elipar Freelight in soft start and standard modes; Ultra-Lume 2; Spectrum 800). Standard dye penetration tests were performed and the data summarised in a 2-way contingency table of observed frequencies. The Chi-square test was used (p<0.05) to test for significant differences between the lights. For surface hardness, samples of Esthet-X were exposed to the light-curing units (LCUs). Vickers hardness was determined on the upper and the bottom surfaces. Data was subjected to statistical analysis using ANOVA (p<0.05). Shear bond strength was determined using a push out method. Comparisons (ANOVA, p<0.05) were made between the different curing protocols. No significant difference in microleakage could be demonstrated between the different LCUs at the enamel side (p=0.60). At the dentin side only the Elipar Freelight (soft start), could significantly reduce microleakage (p<0.01). The hardness score for the halogen light was significantly lower than for the LED lights (p<0.01). The Spectrum 800 and the Elipar Freelight (soft start) have significantly higher shear bond strengths than the others (p<0.01). It was concluded that the LED source is more efficient for a comparable overall power output.

The purpose of the present study was to evaluate in vitro the degree of marginal leakage in Class V cavities involving the cementoenamel junction. Cavities were 4 mm wide and 2 mm deep. The specimens received dentin pretreatment (37% phosphoric acid) followed by the Single Bond (3M) adhesive system application. The 40 specimens were then divided into four groups: Group 1 (control); Group 2 (Nd:YAG laser at 120 mJ/pulse, frequency of 10 Hz, power of 1.2 W); Group 3 (Nd:YAG laser at 140 mJ/pulse, frequency of 10 Hz, power of 1.4 W); Group 4 (Nd:YAG laser at 160 mJ/pulse, frequency of 10 Hz, power of 1.6 W). The cavities were restored with Z100 composite resin (3M) and light cured at 300-600 mW/cm2 light intensity. Specimens were thermocycled to 500 cycles from 2-50 degrees C. After that, they were dried and sealed with nail varnish, respecting 1 mm around the restorations, and immersed in 0.5% methylene blue solution for 4 h. After this period, the teeth were rinsed, dried, sectioned, and analyzed in a stereoscopic loupe. The highest leakage scores were considered for each specimen. The results were statistically analyzed by the analysis of variance (ANOVA) - Kruskal-Wallis test to the 5% level. For both the enamel and cementum, there was a decrease in marginal leakage with the application of laser energy; no significant differences were observed for Groups 2, 3, and 4. The results also showed a smaller tendency to marginal leakage on the cementum than on the enamel.

Reasons for Performing Study: Surgical endodontic therapy is a conservative dental technique used in horses with some degree of clinical success. Failure of this procedure can partially be explained by inadequate sealing of the root apices with resultant microleakage in the periapical area., Objectives: To assess and compare in vitro sealing ability of 3 different dental restorative materials used as apical sealants during equine surgical endodontics., Methods: Thirty extracted equine cheek teeth were divided randomly into 3 groups and subjected to apicoectomy and apical sealing using 3 materials: reinforced zinc oxide-eugenol cement; intermediate restorative material (IRM); a resin-modified glass ionomer; and amalgam. After apical sealing, the teeth were submerged in a solution of Procion Brilliant Cresyl Blue stain for a period of 7 days. The teeth were then washed, embedded in resin, sectioned and assessed microscopically for dye leakage around the apical restorations., Results: Although the materials proved effective as apical sealants, some dye leakage was encountered in all 3 groups with no statistical difference (P = 0.114)., Conclusions and Potential Relevance: IRM, a resin-modified glass ionomer and amalgam all showed comparative features as apical sealants when used in vitro in equine teeth. IRM is currently regarded as the superior material in clinical situations due to its ease of handling and lesser sensitivity to environmental moisture during placement compared to the other 2 materials.

Objective: To compare enamel and dentin microleakage of three single-bottle dentin-bonding agents (DBA) (One-Step, Single Bond, and Dentamed P&B) on teeth that were then subjected to thermocycling and occlusal loading., Method and Materials: Class 5 cavities were prepared on the buccal and lingual surfaces of 30 extracted human molars and divided into three groups. The occlusal margins were in enamel, and the cervical margins were in cementum. DBA were applied strictly according to the manufacturers' recommendations, and the preparations were restored with resin composite. Specimens were subjected to 2,000 intermittent occlusal loads and 3,000 thermocycles and then immersed in 0.5% basic fuchsin dye for 72 hours. Four consecutive sections were cut for each specimen and examined under a stereomicroscope. The extent of dye penetration was measured and recorded using a nonparametric scale from 0 to 4., Results: The Mann-Whitney U test showed a significant difference at cementum margins between One-Step and Dentamed P&B, as well as between Single Bond and Dentamed P&B, and an insignificant difference between Single Bond and One-Step. There was no significant difference in dye penetration at enamel margins between the three DBA., Conclusion: Under combined use of occlusal loads and thermocycling, the sealing ability of single-bottle DBA at dentin margins ranged from good for One-Step to moderate for Single Bond to poor for Dentamed P&B. At enamel margins, all materials performed equally well.

The goal of adhesive dentistry is to restore the peripheral seal of dentin lost from removal of enamel. Unfortunately, the hybrid layer (HL) that is used to create that seal is permeable to small ions or molecules, even in the absence of detectable, interfacial gap formation via nanoleakage. This nanoleakage results from several mechanisms including incomplete infiltration of adhesive monomers into demineralized collagen matrix, presence of hydrophilic monomers, and insufficient removal of solvent or water that remains trapped inside the HL. These mechanisms lead to a porous interface with nanometer-sized channels that increase the permeability of the HL. The null hypothesis tested in this study was that water and acidic solution storage are able to alter in vitro the resin-dentin interface, further increasing the marginal hybrid layer (MHL) permeability. Class II cavities were made in vitro. The specimens were stored in water for 1 week and in lactic acid solution for 3 days. Polyvinyl siloxane impressions of restoration margins were taken before and after storage in water and lactic acid solution. Polyether replicas were obtained using the silicon impressions as molds. Replicas and original samples were observed under scanning electron microscopy. Lines of water droplets were detected on MHLs and overlying adhesive only after storage. Replicas obtained after acidic solution storage showed great numbers of irregularities such as gaps, voids, and degradation of the dentin-restoration surface margin, but also a great number of droplets. Dentin-restoration resin interfaces absorb water and are damaged by storage in dilute lactic acid. The presence of water droplets probably indicates water that flows out of the interface during the setting time of the impression and thus represents an index of marginal HL water permeability.

Aim: (i) To compare the root-end sealing ability of IRM Caps (IRM), Fuji IX Capsules (Fuji IX) and Pro Root MTA Tooth-Coloured Formula (MTA) in teeth obtained from cadavers. (ii) Further research on leakage study methodology by means of comparison of the fluid transport method (FTM) and capillary flow porometry (CFP)., Methodology: Root canal treatment was performed on 33 cadaver teeth in situ 2 weeks prior to root resection and ultrasonic retropreparation (S12/90 degrees D-tip on Suni-Max), after which the teeth were retrieved from the cadavers. Two teeth were kept as positive and negative controls. The other teeth were divided in three different groups at random, with each group receiving one of the retrofill materials. Retrofills were exposed to water 5 min after placement. The teeth were stored at 37 degrees C for 12 h after which the root filling was removed. Microleakage (L in microL day(-1)) was measured for 24 h under a pressure of 1.2 atm using FTM and recorded as L = 0, 0 < L < or = 10, L > 10. The measurements were repeated after 1 and 6 months. After 6 months, leakage was also assessed by CFP in order to measure through pores and their diameters. Results were analysed statistically using nonparametric Kruskal-Wallis and Mann-Whitney U-tests, and Spearman correlation coefficients between the results of both methods were calculated. The level of significance was set at 0.05., Results: (i) A statistically significant difference could be demonstrated between Fuji IX and IRM at 1 month with FTM. FTM revealed a significant difference between Fuji IX and the other materials at 6 months, whereas CFP did not. However, using both methods, Fuji IX showed the best result. (ii) When comparing both techniques, CFP demonstrated through pores in all teeth, whereas with FTM in only 14 of the 31 teeth could through pores be demonstrated. A positive correlation between both methods was demonstrated., Conclusions: Under the conditions of this study (i) the conventionally setting glass-ionomer cement Fuji IX showed the best results when used as a root-end material and (ii) CFP appeared to be a useful method for leakage evaluation of through pores in endodontics.

Incomplete filling of the root canal is one of the major causes of endodontic failure. Endodontic filling techniques and materials which perfectly seal the canal are essential for the success of endodontic treatment. Different in vitro tests are being used to test the sealing efficiency of endodontic filling techniques and materials. A large amount of these tests are leakage tests which measure the penetration of a tracer along the root canal filling. Tracers mainly are dyes, radio-isotopes, bacteria, bacterial metabolites, fungi and others. Apart from the tracer penetration techniques there are also other techniques. The electrochemical technique measures electrical current passing through the void along the root canal filling. The fluid transport method evaluates through-and-through voids along the canal filling. With this technique pressure on the water at the coronal side of the root canal filling is increased. In case of leakage, this will be registered based on the movement of an air bubble in a capillary attached to the end of the root. All of the described methods have their limitations. The largest limitations are the low reproducibility of some of the methods and the absence of standardization. Capillary flow porometry, a method well-known from the industry, has recently been applied in dentistry. With this method through pores can be evaluated in a standardised and reproducible way. Voids which do not extend along the entire root canal filling still have to be evaluated with other methods. Despite of the shortcomings of the in vitro leakage tests, they remain useful as an initial screening of new materials and techniques for canal obturation.

Objective: The purpose of this study was to introduce a new method for quantitative testing of endodontic leakage., Study Design: Eighty straight maxillary anterior teeth were divided randomly into 3 experimental groups of 20 samples each and 2 control groups. The experimental groups were prepared using the modified double-flared technique and obturated by lateral compaction of cold gutta-percha with Pulp Canal Sealer EWT, Sealapex, or AH Plus sealer. With the leakage test device, coronal 1 mol/L glucose solution was forced under a hydrostatic pressure of 1.5 kPa toward the apical part of the root. Leakage was measured by the concentration of leaked glucose in apical reservoir at 1, 2, 4, 7, 10, 15, 20, and 30 days with the enzymatic glucose oxidase method., Results: No significant difference of sealing ability was found among 3 test groups at 1, 2, 4, and 7 days. From the tenth day, Pulp Canal Sealer EWT showed the highest leakage, and the leakage was not significantly different between Sealapex and AH Plus., Conclusions: The quantitative method is sensitive, nondestructive, and clinically relevant. Pulp Canal Sealer EWT showed more leakage than Sealapex and AH Plus in most observation time.

Polymerase chain reaction (PCR) followed by reverse dot blot was used to detect Enterococcus faecalis leakage through mineral trioxide aggregate (MTA) apical obturations of pulpless teeth with open apices. Prepared root canals of 34 extracted teeth were given a standard apical foramen opening and received orthograde apical obturation with MTA; three groups had 1-, 2-, or 3-mm thickness. Sterilized specimens were inoculated with E. faecalis and incubated in sterile medium. DNA extracted from the specimens was amplified by polymerase chain reaction, which yielded a specific segment of E. faecalis 16S rDNA. On day 10 of incubation, no specimens were contaminated. On day 50, almost 17% of specimens were contaminated, with no statistically significant difference between groups (Chi-square = 0.48; df = 2; p = 0.787). Therefore, MTA provides an adequate seal even in cases of orthograde apical obturation of pulpless teeth with open apices.

Purpose: To examine the sealing ability of compomers, used in combination with dentin bonding agents, compared to other classes of tooth-colored materials., Methods: Thirty wedge-shaped cervical cavities were cut in extracted teeth, with the gingival cavosurface margin involving dentin. Five cavities each were restored with one of the following: the compomers Dyract AP/Prime & Bond NT, F2000 Compomer/Adhesive or Hytac Aplitip/Prompt L-Pop; a conventional glass-ionomer, Ketac Fil Aplicap; a resin-modified glass-ionomer, Fuji II LC Improved; or a resin-based composite, Z100 MP/Scotchbond 1. All teeth were restored, stored moist for 24 hours, then varnished (except the restorations) before thermocycling in rhodamine B dye solution for 1000 cycles (between baths of 6 degrees C and 60 degrees C). The teeth were sectioned longitudinally through the restorations before examination with a confocal microscope. A scale of 0 to 3 was used to score the dye leakage along the enamel margin as well as the gingival margin., Results: The results showed that at the enamel margin, all materials gave a median score of 0 except Z100 MP (median score 3). Leakage was noted at the gingival margin of all materials (median score of 3 except Dyract AP with a median score of 2).

Purpose: To assess quantitatively the influence of salivary contamination in vitro on marginal microleakage of pit and fissure sealants., Methods: Forty-eight sound human third molars were selected and assigned to three groups: 1) Fluroshield (F), 2) Single Bond + Fluroshield (SBF) and 3) Ketac-fil (KF). Each group was divided into two subgroups: control (C) and with salivary contamination (SC). The occlusal surfaces were etched with 40% polyacrylic acid for 10 seconds or 37% phosphoric acid for 30 seconds, for either glass-ionomer or resin-based sealants, respectively. Specimens were contaminated with 0.25 mL of fresh human saliva for 20 seconds and dried afterwards. The sealants were placed and samples were thermocycled, immersed in a 0.2% Rhodamine B solution for 24 hours, embedded in acrylic resin and serially sectioned. The sections were viewed under an optical microscope connected to a computer and a video camera, and the images obtained were digitized. The extent of dye penetration along buccal and lingual slopes was measured in millimeters, using specific computer software, and converted into percentage, according to the fissures extension., Results: The microleakage means (%) were: F/C:0 (+/- 0); F/SC: 31.71 (+/- 31.69); SBF/C: 0 (+/- 0); SBF/SC: 0 (+/- 0); KF/C: 0.98 (+/- 2.79) and KF/SC: 11.82 (+/- 15.45). ANOVA and Tukey test showed that salivary contamination provided significant increase in microleakage. Under salivary contamination, only SBF provided complete marginal sealing. When F and KF were compared, the glass-ionomer cement yielded the best sealing.

This study evaluated the root-end sealing ability of mineral trioxide aggregate (MTA Angelus), reinforced zinc oxide-eugenol cement (Super EBA), resin-modified glass ionomer (Vitremer) and zinc-free amalgam (GS-80) (control). The root canals of eighty human lower molars were accessed, cleansed, shaped and obturated. Apexes were resected and cavities were prepared. Teeth were divided into 4 groups of 40 cavities, root-end filled with the materials, and immersed in methylene blue for 72 h at 37 degrees C. Roots were then sectioned transversally at each millimeter and evaluated under magnification, observing the dye penetration in each section. Data were evaluated using Kruskal-Wallis test at a 5% level of significance, showing the differences among all materials (p < 0.001). The crescent order of microleakage was MTA < Vitremer < Super EBA < amalgam. Higher leakage levels were observed in the first millimeter sections of amalgam, Vitremer and MTA, when compared with the third millimeter section (p < 0.05).

The suitability of bovine and swine teeth has been evaluated when they are used as substitutes for extracted human teeth in varied researches. This study evaluated in vitro the marginal microleakage in human, bovine and swine enamel. Cubic cavities (2 x 2 x 2 mm3) were prepared in enamel blocks from human, swine and bovine teeth. The cavities were filled with composite resin and conventional glass-ionomer cement. All the samples were thermocycled for 1,000 cycles (5 +/- 2 degrees C - 55 +/- 2 degrees C) and immersed in 2% methylene blue solution for 12 hours. The microleakage was quantified by a spectrophotometric technique. The results were statistically analyzed using ANOVA and Tukey's test. The glass-ionomer cement presented significantly higher leakage means (microg/ml +/- SD) than the composite resin for all substrates (0.0695 +/- 0.01313 vs. 0.0471 +/- 0.0163, p < 0.01). No significant differences were found between bovine and swine enamel (0.0668 +/- 0.0246 vs. 0.0674 +/- 0.0286); however, both presented statistically higher leakage means than human enamel (0.0407 +/- 0.0195, p < 0.01). It was concluded that the microleakage pattern was affected by substrates, and that bovine and swine substrates allow higher marginal leakage than human substrates. The results indicate there should be precaution in the substitution of human substrate in laboratory studies of microleakage.

The aim of this study was to evaluate the sealing ability of materials filled in the orifice after root canal treatment. A total of 100 root canal-treated teeth were divided into six experimental groups: 1, Protect Liner F (PL); 2, Panavia F (PF); 3, DC core-Light cured (DCL); 4, DC core-Chemically cured (DCC); 5, Super-EBA (SE); 6, Ketac (KC). The materials were filled--to a depth of 4 mm--in the coronal part of the root canals, and evaluated for microleakage. The number of teeth that failed to stop dye penetration in the filled materials differed statistically between PL and DCL or SE or KC, PF and SE or KC, DCC and KC, DCL and KC. The mean distance of dye penetration differed significantly between PL and SE or DCC, PF and SE or DCC. Hence, these results indicated the advantageous sealing ability of adhesive and flowable materials.

Purpose: To evaluate the effects of 1) wall grinding status, 2) thermal stress, and 3) time of polishing on sealing performance of two one-step bonding systems in cervical cavities., Materials and Methods: Semicircular cavities with dimensions of 3 x 3 x 1.5 mm were prepared along the CEJ of extracted human premolars. In experiment 1, the cavity walls were additionally ground with round steel diamond burs (regularly ground) or finished with superfine diamond burs. The cavities were treated with AQ Bond (AQ) or One-up Bond F (OB) and filled with a resin composite. Then thermocycling (5 degrees C to 55 degrees C, 1000 x) was performed. In experiment 2, the regularly ground cavities were used. After restoration, the teeth were subjected to thermocycling (1,000 to 5,000 x). In experiment 3, the restorations in the regularly ground cavities were polished immediately or 24 h after filling. No thermocycling was carried out in this group. All specimens were immersed in a dye solution for 2 h. Microleakage at coronal and apical walls was evaluated on the longitudinal sections of the restorations., Results: For OB, the cavities finished with superfine burs exhibited more microleakage at the coronal wall than the regularly ground cavity (p < 0.05). The leakage at the coronal walls increased with the number of thermal cycles for both systems (p < 0.05). The delayed polishing generated better adaptation at the apical wall of AQ and at the coronal wall of OB (p < 0.05)., Conclusion: Grinding status, thermocycling, and time of polishing had influences on the sealing performance of the two one-step adhesive systems.

This study compared apical leakage in mesial roots of mandibular molars that resulted from three different instrumentation/obturation techniques performed in a simulated clinical setting: hand instrumentation by nickel-titanium files followed by cold lateral condensation of gutta-percha/sealer; rotary instrumentation followed by the Microseal system of obturation with softened gutta-percha; and rotary instrumentation followed by obturation with the Thermafil system. Lateral condensation generally was measured superior to the Thermafil method for preventing apical dye penetration while no consistent statistical differences were seen between the lateral condensation and Microseal groups.

Microleakage testing continues to be undertaken using a variety of techniques and methodologies. This study compared four microleakage tracers to determine if a difference exists in their ability to demonstrate microleakage on a single dental amalgam restorative material by testing in two phases. Class V amalgam restorations were placed on the facial surfaces of 105 extracted human premolars with all margins in enamel. The teeth were stored at 37 degrees C in water for two weeks except during thermocycling for 2500 cycles between 8 degrees C and 48 degrees C. The teeth were prepared for microleakage testing by sealing the external surfaces with nail polish and tinfoil, leaving the restoration and surrounding 1 mm exposed. In the first phase, four groups of 15 teeth were randomly assigned to 0.5% basic fuchsin dye, 2.0% fluorescent dye, 1.5% reactive orange 14 and 45Ca. In the second phase, another three groups of 15 teeth were immersed in 45Ca, then immersed in one of the remaining three tracers. Ridit analysis and Newman-Keuls multiple comparisons were used to compare the groups at a significance level of 0.05. The results indicate that there are differences in observed microleakage between tracers and there is no statistical influence on dye tracers by initial immersion in 45Ca.

Objectives: The aim of this study was to evaluate nanoleakage patterns following silver methenamine staining of restorations bonded with a total-etch single bottle system, a self-etching primer system and a total-etch single bottle system after collagen depletion., Methods: The dentin bonding systems used in this study were Prime and bond 2.1 (PB) and Clearfil SE Bond (CSEB). Cavities were made in grounded labial surfaces of 15 extracted bovine lower incisors, randomly divided into 3 Groups. Group 1 (PB), Group 2 (CSEB) and Group 3 (PB/SH) PB after collagen depletion with sodium hypochlorite (SH). The specimens were restored, sectioned and submitted to silver methenamine staining, polished and observed with low-vacuum back-scattered SEM. One way ANOVA and multiple-comparison Tukey's test were used for statistical analysis of the leakage scores., Results: PB presented significantly greater silver deposition and a distinct pattern when compared to CSEB. No silver deposition was detected for PB after collagen depletion., Significance: The dentine bonding systems tested were unable to prevent nanoleakage when used according to the manufacturers' instructions; however, CSEB presented a lower level of silver deposition. Collagen depletion prior to PB application may prevent nanoleakage occurrence in dentine walls. Silver methenamine staining may be a useful method for detection of nanoleakage in dentine when the collagen fibrils remain exposed within the hybrid layers.

Aim: To evaluate the apical seal of canals filled with a core-carrier obturator following root-end resection with and without a root-end filling., Methodology: Thirty single-rooted human teeth with single canals were used. Root canal treatment was performed and canals filled with a core-carrier obturation technique. The teeth were then randomly assigned to three groups (n = 10). In the first group root canal filling only was performed. After orthograde filling, the teeth of the second group were resected apically, perpendicular to the major axis of the root. In the third group after apical resection, a root-end cavity was prepared using ultrasonic diamond retrotips and the cavities filled with Super-EBA cement. During a period of 3 h and with a headspace pressure of 0.12 atm, methylene-blue solution was forced through a tube that was connected to the apical end of each tooth specimen. The coronal end of the tooth was connected to a capillary tube containing an air bubble. Leakage was evaluated by observing the distal displacement of the air bubble. The roots were then sectioned along their long axis. Using a stereomicroscope, linear dye infiltration at the dentine-cement interface was determined. Kruskal-Wallis and Mann-Whitney tests were used to compare the three groups., Results: Linear dye infiltration was significantly greater in root canals filled with the core-carrier obturators and resected apically (0.9 +/- 0.9 mm) when compared with those that had root-end fillings (0.2 +/- 0.4 mm). Air bubble displacement was not observed., Conclusion: Root-end filling improves the sealing of roots with core-carrier obturation following root-end resection.

Objectives: This study evaluated the effect of pumice prophylaxis on the level of microleakage around and between the sealant and enamel., Materials and Methods: A total of 32 freshly extracted sound upper first premolars, assigned as suitable for sealant application, were chosen and divided randomly into two groups: (1) a test group, without prophylaxis; and (2) a control group, with prophylaxis. Sealant was applied to all teeth using the same conventional technique, with prophylaxis being omitted in the test group. The sealed teeth were thermocycled (120 x 30 s, 5 and 55 degrees C cycles) and then immersed in 2% Basic Fuchsin solution for 72 h. Each tooth was sectioned and examined for dye penetration under a stereomicroscope (x 60 magnification)., Results: No dye penetration was seen in 19 (29.6%) of the teeth in the test group and 36 (56.2%) of the teeth in the control group. Dye had penetrated to the base of the fissure in 31 (48.4%) of the teeth in the test group and 23 (35.9%) of the teeth in the control group. Using a chi-square test for trend, the frequency of microleakage was significantly higher in the test group compared to the controls (P < 0.016)., Conclusion: Prophylaxis has a role in improving sealant retention. Removing this step may cause an increase in microleakage.

Objectives: The aim of our in vitro study was to quantitatively evaluate dentin microleakage by means of the impedance technique., Methods: Forty-five 2 mm thick dentin disks were embedded in a hollow polyurethane resin cylinder. The system used was a 'like' permeation cell. Standard cylindrical cavities (1.5 mm deep, 3.5 mm diameter) were prepared on the occlusal side of the disk. The current passing through the dentin was measured to calculate impedance and to establish resistance of the sample. The doses were then randomly divided into nine groups (n = 5). Each group was bounded with a different adhesive system and filled with microhybrid composite resin (Filtek P60). The initial measurement with the empty cavity and the record measurement (t = 0) were performed to evaluate initial resistance after filling. Samples were then thermocycled., Results: At t = 0, the highest value was obtained with EP (550%), the lowest with PLP (115%). The values of other adhesives ranged in a group (350-450%) without statistical difference. After thermocycling, all groups exhibited no significant difference (350-230%) except PLP (50%). The lower joint degradation rate (5%) was obtained with OS with a significant difference for all systems, the higher with PLP (35%). The results for other adhesives ranged from 20 to 27% without significant difference., Significance: Dentin microleakage may be quantified with the impedance technique and this has shown that, except for PLP, the differences between the two families of adhesives are slight. This methodology is able to prove the influence of thermocycling in terms of joint degradation., (Copyright 2003 Academy of Dental Materials)

The efficacy of using invasive and non-invasive techniques was assessed by Scanning electron microscopy, and by microleakage of Glass ionomer (GC VII, Fuji) and Resin based sealant (Helioseal-F, Ivoclar Vivadent). 100 young premolars were used for this study, and they were divided into four groups: Group I: non-invasive technique GC VII, Group II: Invasive GC VII, Group III: Non-Invasive Helioseal-F, Group IV: Invasive, Helioseal-F. 5 teeth from each group were evaluated under SEM. It was seen that the flow and adaptation of GC VII was slightly better than Helioseal F, and the invasive technique provided the best flow and adaptation. For microleakage analysis 5% methylene blue was used. It was seen that minimal microleakage was seen in Group IV (P<0.01). Considering the recent controversies using resin based sealants, it can be said that GC VII can be a viable alternative for pit and fissure sealants.

Objective: The aim of this study was to investigate the in-vitro marginal adaptation of all-ceramic class II inlays which were luted with conventional multi-stage pre-treatment cements and one new type of cement, which requires no conditioning., Methods: The marginal adaptation of 56 all-ceramic inlays was determined with scanning electron microscopy and microleakage tests. The marginal integrity of each tooth was evaluated at cement-dentin and cement-enamel junctions, with regard to the transitions between tooth-cement and cement-inlay. The inlays were luted on human molars with two resin cements, one compomer, one resin modified glass-ionomer and one new resin cement in accordance with the manufacture's recommended pre-treatment. Light- and chemical-curing modifications were investigated. All tests were performed after thermal cycling and mechanical loading (TCML)., Results: For the resin cements and the new material the marginal integrity was higher than 90% before and after TCML. The marginal adaptation was between 55-80% for the resin modified glass-ionomer and lower than 20% for the compomer. The microleakage was lower than 20% for all cements, only the compomer showed values up to 100% penetration., Significance: The difference in marginal integrity between the new universal resin cement without any tooth pre-treatment and conventional resin cements after total-etching, priming and bonding was not significant. Resin GIC may be used with restrictions and compomer cement should not be used with all-ceramic class II inlay restorations.

Purpose: To compare microleakage of Class V restorations filled with a novel low-shrinkage resin-based composite cured by a high intensity light and a combination of controls including a conventional composite cured by conventional and soft-start regimes., Methods: Forty-two intact premolar and molar teeth were randomly assigned to seven groups and filled with a low-shrinkage composite or a conventional composite, bonded with one of two bonding materials (Excite or Prime&Bond NT) and cured with either a high intensity light, a soft-start regime or a conventional light regime. Cavities were cut in both the buccal and lingual aspects of each tooth with half of the preparation in enamel and half in dentin/cementum. The teeth were thermocycled and the restorations examined microscopically for leakage using Procion Brilliant Red as a marker., Results: None of the groups showed microleakage at the enamel margins. All groups showed leakage at the gingival margins. At the gingival margins there was no significant difference between the low-shrinkage composite, bonded with the manufacturer's adhesive, and cured by high intensity regime, and the conventional composite bonded by the manufacture's adhesive and cured by one of two soft start regimes. Nor was there a significant difference between the low-shrinkage composite, bonded by the manufacturer's adhesive and cured by either the high intensity regime or one of two soft start regimes. The low-shrinkage material, bonded by the manufacturer's adhesive and cured by the high intensity regime showed significantly less microleakage than the conventional composite, bonded by the manufacturer's adhesive and cured with a conventional light source., Clinical Significance: Gingival marginal microleakage is not prevented by the use of a low-shrinkage composite cured by a high intensity light. If time were an essential consideration, the low shrinkage composite cured by a high intensity regime may offer clinical advantages.

This study compared the coronal microleakage of three restorative materials used to seal the access cavity in root treated teeth. Thirty six teeth were prepared and three experimental groups were obturated and the access cavity filled with different materials; Group A--Intermediate Restorative Material, Group B--Fuji II and Group C--Dyract AP. Microleakage was assessed by Indian ink penetration. The mean coronal dye leakage for Group A was 0.895 mm, for Group B 1.914 mm and for Group C 3.245 mm. There was significantly (p < 0.05) more dye leakage in teeth restored with Dyract AP compared to those with Fuji II or IRM.

Objective: This study investigated the effect of light-curing modes on the microleakage of cervical resin composite restorations., Methods: Eighty wedge-shaped cervical cavities, C-factor approximately 1.3, were prepared on the labial surface of bovine incisors. The cavities were treated with a two-step experimental self-etching primer adhesive system containing an antibacterial monomer (ABF), according to the manufacturer's instructions, and filled with a single increment of a hybrid resin composite. The restorations were allocated randomly into four groups of 20: Group 1-the restorations were light-cured for 40 s with a conventional light-curing unit (New Light VL-II); Group 2-the restorations were cured with Candelux using a two-step mode; Group 3-the restorations were cured with Astralis 7 using a ramping mode; Group 4-the restorations were light-cured for 3 s with a plasma arc light-curing unit (Wave Light). Half of the specimens from each group were subjected to thermocycling (5-60 degrees C, 15 s dwell time, 5000 cycles) prior to immersion in 0.5% basic fuchsin. The teeth were sectioned and the degrees of dye penetration were scored. The data were analyzed with either the Kruskal-Wallis test or the Mann-Whitney U-test (p < 0.05), Results: No significant differences were found in the microleakage scores among the light-curing modes used. The restorations tended to display more microleakage when they were subjected to thermocycling, but the differences were not statistically significant., Conclusions: These findings suggest that light-curing modes may have no effect on the microleakage of cervical cavities with a small C-factor, as is the case in this study.

Aim: To investigate whether Ca(OH)2 in four different agents alters the physical properties (Exp. I) and sealing ability (Exp. II) of root canal sealers., Experiment: (Exp. I) Calcipex (Nippon Sika-Yakuhin, Shimonoseki, Japan), Vitapex (Neo-Dental, Tokyo, Japan), Calkyl (Showa Yakuhin, Tokyo, Japan), and Ca(OH)2 were used as Ca(OH)2 agents. Four sealers were tested for flow, working time, setting time, and film thickness: Canals (Showa Yakuhin), Canals-N (Showa Yakuhin), Ketac -Endo (Espe, Seefeld, Germany), and Sealapex (Kerr, Romulus, MI, USA). Each Ca(OH)2 agent was added to 10 vol.% of each sealer, and the mixture and controls without a Ca(OH)2 agent were tested according to ISO specifications. Measurements were compared using Student's t-tests (P < 0.05). (Exp. II) After removing Ca(OH)2 agents applied to the root canals of 100 extracted human teeth, canals were filled with sealer. Controls were filled with each sealer without Ca(OH)2 agents. Sealing ability was evaluated using distance of dye penetration from the apices. Dye penetration data were compared using analysis of variance and post hoc Newman-Keuls test (P < 0.05)., Results: Ca(OH)2 agents influenced the physical properties of the sealers. Flow and setting time met ISO requirements, but film thickness and working time did not. Apical sealing ability of all four sealers was influenced by Ca(OH)2 agents. The sealing ability of Sealapex improved with all Ca(OH)2 agents. The physical and sealing abilities varied among the other sealers., Conclusions: Contact with Ca(OH)2 agents left on the canal wall caused considerable changes to the sealing ability of sealers.

The aim of this investigation was to compare the microleakage of composite resin (Z-100) and shear bond strength to bovine dentin using different types of adhesive systems (Scotch Bond Multi-Purpose, All-Bond 2, One-Step, and Perma Quick) to compare and correlate microleakage to shear bond strength. For the microleakage aspect of the study, 20 class V were prepared (bovine incisors) with 90-degree cavosurface margins and were located at the cemento-enamel junction using a template. Each dentin bonding system was applied to five cavities following the manufacturer's instructions and restored with Z-100 composite resin. After 24 hours of storage in distilled water at 37 degrees C, the teeth were immersed in 2% basic fuchsin dye. All teeth were sectioned in a mesiodistal direction using a diamond saw, and each section was then inspected under a stereomacroscope. For the shear bond strength aspect of the study, 20 bovine incisors were centrally horizontally mounted in Teflon mold with cold cure acrylic resin. Flat labial dentin surfaces were prepared using different grit silicon carbide abrasive wheels. Five specimens were used for each of the bonding agent systems. Each specimen was bonded with restorative composite resin (Z-100) and applied to the treated dentinal surface through a split Teflon mold. All specimens were stored in distilled water at 37 degrees C for 24 hours. The bonds were stressed using shear forces at a crosshead speed of 0.5mm/min using an Instron Universal testing machine. Findings indicate none of the systems tested in this study were free from microleakage. Scotch bond multi-purpose achieved the best seal, with One-Step being second best, while All-Bond 2 and Perma Quick had the poorest seal. However, there were significant differences among the shear bond strengths of the four bonding systems tested. Scotch Bond Multi-Purpose has a higher bond strength to composite resin when compared to the other dentin adhesives. The study also concluded there is no association between microleakage and shear bond strength.

Objectives: This study compares the marginal adaptation of a new self-adhesive universal resin cement with only one application step, to the marginal adaptation of established cements and their corresponding adhesive systems., Methods: All-ceramic crowns were inserted on human molars using a new self-adhesive universal resin cement without and with one pre-treatment step, a resin cement with a smear-layer removing and a compomer cement with a smear-layer dissolving adhesive system. After simulation of five years oral stress, the marginal adaptation was evaluated by dye penetration and scanning electronic microscope analysis using the replica technique., Results: Scanning electron microscopy: all investigated luting agents showed comparable amounts of 'perfect margin' ranging between 88-98% (median). Dye penetration: the self-adhesive system had significantly lower dye penetration (18-25%, median)., Significance: The results indicate that a self-adhesive universal resin cement without pre-treatment can provide a marginal adaptation at dentin which is comparable to established luting agents.

This study investigated sealant penetration and dye microleakage of a resin composite system, a compomer system, and a resin-modified glass-ionomer cement in artificially grooved fissures in human molars. Ionosit Seal penetrated 99% of the artificial crevices, whereas Dyract Seal penetrated 97%. The penetration of Helioseal F at 90% was statistically different (P<.0001) from the other 2 materials. Microleakage dye penetration occurred in 22% of the Dyract Seal samples, while it occurred in 5% of Healioseal F and 7% of Ionosit Seal samples. The viscosity and flow properties of the 3 sealants allowed the materials to penetrate the artificial grooves, but they did not seem to affect their sealing capacity.

Aim: To compare the sealing ability of the endodontic sealers AH Plus, Sealer 26 and Endofill in premolar teeth of dogs exposed to the oral cavity after post-preparation., Methodology: Forty teeth with two canals each underwent root canal cleaning and shaping. Before filling, the canals were randomly distributed into three groups according to the sealer to be used: Group 1 - AH Plus; Group 2 - Sealer 26; and Group 3 - Endofill (Dentsply, Indústria e Comércio Ltda.). Immediately after filling, the gutta percha and sealer were partially removed from the canals, leaving material only in the apical third of the root. The teeth were temporarily sealed with glass ionomer sealer for 72 h to ensure setting. The coronal seal was then removed and the canals were exposed to the oral cavity for 45 days. The animals were euthanased and their mandibles and maxillae were removed. After abundant irrigation with distilled water, the canals were dried and filled with India ink. The teeth were sealed again for 96 h before extraction. The roots of the extracted premolars were separated and stored in labelled test tubes. The roots were cleared and the extent of dye penetration was measured with a 20x stereoscopic magnifying lens., Results: Statistical analysis revealed that there were significant differences between the sealers studied (P < 0.001). Means for the extent of dye penetration for AH Plus, Endofill and Sealer 26 were, respectively, 0.13, 2.27 and 3.08 mm., Conclusions: After 45 days exposure to the oral cavity, none of the sealers was capable of preventing leakage and coronal dye penetration. There were significant differences between the sealers studied, in terms of mean dye penetration.

Thermocycling simulates, in vitro, thermal changes that occur in the oral cavity. The aim of this study was to evaluate the influence of the number of cycles on microleakage. Class V cavities (1.5 mm deep, 3 mm in height and 3 mm in width) were prepared in bovine teeth, restored with a Single Bond/Z250 restorative system (3M/ESPE) and then divided into five groups of ten teeth each: group 1 was not thermocycled (control group), and groups 2, 3, 4 and 5 were thermocycled 500, 1,000, 2,500 and 5,000 times, respectively (5 degrees -55 degrees +/- 2 degrees C, 15 s dwell time). The teeth were immersed in 0.5% basic fuchsin aqueous solution for 24 h, sectioned and the sections with the highest degree of microleakage were selected, scanned and the extent of dye penetration was measured by the ImageTool program. The results submitted to one-way ANOVA showed no significant differences between the groups (p > 0.05). The averages of microleakage values in millimeters were: group 1 (3.92); group 2 (3.13); group 3 (4.48); group 4 (4.33) and group 5 (3.42). Thus, it was concluded that there is no relation between the increase of the number of cycles and the increase in microleakage.

Objective: This in vitro study compared the microleakage of resin composite restorations placed in Class II cavity preparations using an incremental placement technique with and without the addition of precured resin composite inserts., Method and Materials: Sixty standardized mesio-occlusal and disto-occlusal cavities were prepared in 30 recently extracted molar teeth. Twenty cavities were restored by employing the incremental placement technique (group I), and 40 cavities were restored using the incremental placement in the presence of precured composite inserts of two sizes: 1 x 3 mm (group II) and 1.25 x 3 mm (group III). The restored teeth were thermocycled for 250 cycles in water baths set at temperatures of 5 degrees C and 50 degrees C using a 30-second dwell time, stained, and sectioned horizontally at the middle of the restoration. Following sectioning, each specimen was microscopically examined at x 4 magnification. The extent of dye penetration at the tooth/restoration interface was scored for each test group, and the scores obtained were subjected to one-way analysis of variance (ANOVA) and Tukey's pairwise comparison at a 95% significance level., Results: The current investigation showed statistically significant differences in dye penetration between the three test groups., Conclusion: The use of precured resin composite inserts with the incremental placement technique in the restoration of Class II cavity preparations seems to improve the marginal seal of the proximal walls of finished restorations.

The purpose of this study was to compare the classical dye-penetration method to a dye-extraction method, with a fluid-filtration method as control. Forty teeth were prepared with a ProFile device and divided into four groups (n = 10 per group) according to the sealer used for the lateral condensation: Pulp Canal Sealer, Sealapex, AH Plus, and Ketac-Endo. The apical seal was evaluated on the same teeth with all three methods, successively: a fluid-filtration method, a dye-penetration method with 2% methylene blue, and a new method where the roots were dissolved in 65% nitric acid to extract the methylene blue before reading the absorbance of the solution. The classical dye penetration did not show any difference among the sealers and showed no correlation with the two other techniques. The fluid filtration (p < 0.01) and the dye extraction (p < 0.01) showed that Sealapex displayed the highest apical leakage. The correlation between the results obtained with these two methods was significant (p = 0.001 and r = 0.7). This study showed the limitation of the classical dye-penetration studies and that the dye-extraction, i.e. dissolution, method gave the same results as fluid filtration but saved much laboratory time.

Endodontic therapy is conducted to effectively seal the root canal system. In vitro methods are used to estimate the quality of the seal, generally by measuring any microleakage that allows the tracers to penetrate along the obturated root canal. The use of bacteria as tracers seems to give the most clinically relevant demonstration of microleakage associated with a root canal system. Many bacterial strains have been used to evaluate marginal leakage, but results are sometimes contradictory, probably because they may depend on the bacterial strain used. In the studies described in this article, the percolation of both calibrated latex microspheres equivalent in diameter (0.4-9.5 microm) to bacteria and three bacterial strains (Actinomyces odontolyticus, Lactobacillus acidophilus, and Pseudomonas fluorescens) was compared in teeth filled using noncompressive and compressive techniques. The depth (d) to which the microspheres and bacteria penetrated varied over the time (t) of contamination according to a logarithmic relation. The slope (S) and the intercept (I, corresponding to penetration after 1 month) of the d = f(In t) plots can serve to quantify penetration over time. Statistical analysis of I by the Newman-Keuls procedure, which couples the tracers and filling techniques, showed that A. odontolyticus and L. acidophilus behave like 4.8-microm particles and P. fluorescens like 2.2-microm particles (corresponding approximately to their size in length) and that noncompressive techniques are less hermetic than compressive techniques. S and I are in direct relation and this relation is independent of the filling technique. Moreover, for the calibrated particles, both I and S varied linearly with the inverse of the square root of the particle diameter, indicating that their displacements are governed solely by Brownian movements and the penetration over time is caused by diffusion phenomena. The size of the tracer is the predominant factor governing its penetration. Inert particles mimic bacterial percolation into the marginal hiatus and can thus be used to model this percolation and establish a relative scale of the behavior of different bacteria during percolation.

This in vitro study compared three different methods to evaluate detectable levels of microleakage in Class II restorations placed with five commercially available packable resin composites: Alert, Glacier, Pyramid, Solitaire 2 and SureFil. A flowable resin composite, Flow-It, was used to line all packable composites. The hybrid resin composite Z100 was also included. The adhesive system used with all groups was Scotchbond MultiPurpose Plus. Standard Class II cavities were prepared on the mesial (enamel margins) and distal (dentin margins) sides of the teeth with no communication between them. Based on a power analysis, 180 permanent human molars were randomly assign to each of six groups with 30 specimens per group. All restorative materials were placed following manufacturers' recommendations. Following restoration and thermocycling, the specimens were stored at room temperature in solutions of 45Ca, methylene blue and rhodamine B, sequentially. Microleakage was ordinal scored as 1 (no penetration), 2 (penetration up to one-third of the cervical floor), 3 (penetration beyond one-third of the cervical floor to the axial wall) and 4 (penetration along the axial wall) by two independent evaluators. Analysis of the occlusal surfaces was also accomplished following the same scheme. In this study, tracers/dyes were evaluated for differences in penetration using generalized estimating equation methodology applied to cumulative logistic regression models. The results showed that Rhodamine B detected more microleakage than 45Ca or methylene blue, and 45Ca generally detected more microleakage than methylene blue.

Water sorption into resin-dentin interfaces precedes hydrolytic degradation. We hypothesized that these processes are morphologically manifested by the uptake of ammoniacal silver nitrate, which is thought to trace hydrophilic domains and water-filled channels within matrices. Water sorption is thought to be nonuniform and can be traced by the use of silver nitrate. Human teeth bonded with an experimental filled-adhesive were aged in artificial saliva (experimental) or non-aqueous mineral oil (control). Specimens retrieved for up to a 12-month period were immersed in 50 wt% ammoniacal silver nitrate and examined by transmission electron microscopy for identification of the changes in their silver uptake. Reticular silver deposits initially identified within the bulk of hybrid layers in the experimental group were gradually reduced over time, but were subsequently replaced by similar deposits that were located along the hybrid layer-adhesive interface. Silver uptake in water-binding domains of the adhesive layers increased with aging, resulting in water tree formation. These water-filled channels may act as potential sites for hydrolytic degradation of resin-dentin bonds.

Purpose: To test how the number of sections affects the maximum depth of tracer penetration., Materials and Methods: This study was simultaneously performed in three different centers. C-shaped Class V cavities were made on 60 human third molars. The cavities were located across the cementum-enamel junction. One restorative system was used: Scotchbond Multi-Purpose and Z100. After restoration, the samples were thermally cycled 3000 times, between 5 and 55 degrees C with a dwell time immersion of 10 seconds. Silver nitrate was used by two centers and basic fuchsin was used by the third. The teeth were longitudinally sectioned with a diamond saw: 5 sections per tooth provided 10 surfaces for evaluation. The penetration of the tracer was recorded on a scale from 0 to 3. The deepest leakage per restoration was identified for comparison with lesser measured values elsewhere in the tooth. The Spearman test was applied to evaluate the relationship between the reference and data from one, two and three sections (i.e. two, four and six measurements). The Kruskal-Wallis test was applied to compare the three centers., Results: Whatever the study center, the Spearman correlation coefficient (r(s)) increased as a function of the number of sections (S) up to three: Center 1 (1S, 0.47; 2S, 0.68; 3S, 1.0), Center 2 (1S, 0.60; 2S, 0.99; 3S, 0.99), Center 3 (S1, 0.40; 2S, 0.73; 3S, 1.0). No statistically significant difference was found between the three study centers.

The quantitative light-induced fluorescence (QLF) method is based on the natural fluorescence of teeth. Currently, the method is predominantly used in vitro and in clinical studies for early detection of carious lesions and for monitoring of de- and remineralization of white spots by quantifying the mineral loss and the size of smooth surface lesions. The objective of this paper was to demonstrate the potential of QLF for application in routine dental care. Experience with QLF was reported by selected cases, which enlightened the advantages of the method for caries detection and for evaluation of preventive interventions in caries-prone patients in daily practice.

Objectives: The submicron hiatus represents a potential space between the base of the collagen network and the mineralized dentin when dentin is acid-etched for bonding. These spaces were observed in SEM studies after acid-etched dentin specimens were critical point dried or dehydrated in hexamethyldisilasane. However, they have never been identified in TEM studies of dentin hybrid layers. This study critically examined the cause of submicron hiati formation using a silver staining technique to measure nanoleakage., Methods: Two multi-step, total-etch adhesives (One-Step, Bisco; Single Bond, 3M) and two single-step, self-etching adhesives (Prompt L-Pop, ESPE; One-Up Bond F, Tokuyama) were examined. Flat dentin surfaces were bonded with these adhesives and a lining composite. In each adhesive group, 0.8mm thick slabs from the same bonded tooth were coated with nail varnish applied 1mm from the bonded interfaces. The varnish was either left to dry completely for 10min before immersing in 50wt% silver nitrate (AgNO(3)) for 24h (group D), or painted on blotted tooth slabs that were immediately dropped into the AgNO(3) solution (group M). After developing, undemineralized, unstained, epoxy resin-embedded sections were prepared for transmission electron microscopy (TEM) to identify the amount and distribution of silver uptake., Results: Nanoleakage patterns were observed in all adhesive-bonded teeth, regardless of brand. Fine reticular silver deposits were also found in the underlying undemineralized dentin. In group D, submicron hiati were seen as tunnels of heavy silver deposits beneath hybrid layers. Specifically, a hiatus occurred between the undemineralized intertubular dentin and a cohesively fractured layer of the same matrix that was attached to the base of the hybrid layer. Hiati were completely absent in group M, regardless of the brand of adhesive., Significance: Submicron hiati are artifacts created by desiccation during specimen processing, and should be referred to as such in future studies of bonded dentin interfaces.

Unlabelled: Dentistry has recently recognized the practicality and benefits of treating damaged and diseased oral tissues under high magnification levels. Initially, enhanced vision was more-or-less restricted to the use of prescription bifocals, awkward magnifying loops, and heavy cumbersome telephoto glasses; the microscope drew little interest and was quickly viewed as another useless and expensive dental gadget. However, owing to the very nature and demands of the therapy, endodontists were quick to accept and adopt this technology, and the manufacturers were quick to adapt and market their surgical microscopes to the endodontic office. Since acceptance leads to progression, we are currently witnessing manufacturers adapting the microscopic and other magnifying lenses to other areas of dentistry. However, choosing and purchasing a microscope involves a great number of issues, including the adequacy of one's present vision, the type of practice conducted, the demands one places on the quality of his or her dentistry, and the amount of time and expense one wishes to devote to becoming competent in using magnification. In addition, one must become familiar with what the different levels of magnification offer, what different depths and widths of field meet their normal practice needs, the amount of space required for the equipment, and whether the investment is cost effective. This article details all of the benefits as well as the difficulties encountered when embarking on a magnification journey., Clinical Significance: The art of dentistry is based on precision. The human naked eye is capable of distinguishing fine detail, but it is no match for what can be accomplished when an image is sharpened and enlarged. The microscope and other forms of magnification fill that need, especially for accomplishing endodontic procedures.

The purposes of this study were to investigate the surface morphology, suface roughness of cavities prepared by Er:YAG laser irradiation, and compared the microleakage degree after composite resin restoration with etched bur cavities, in vitro. In each of the 30 human extracted teeth, two shallow cavities were prepared; one prepared with the Er:YAG laser system on the buccal surface, and one produced on the lingual (palatal) surface with a high-speed turbine. Five cavities from each group were investigated by scanning electron microscopy (SEM), and five were subjected to surface roughness analysis by a colour laser three-dimensional (3D) microscope. The remaining cavities were filled with a composite resin and subjected to a microleakage test under thermocycling. Only bur cavities were acid-etched before filling. Statistical analysis was performed using the Mann-Whitney U test; a value of p <0.01 was considered significant. Morphologically, the prepared cavities showed an irregular surface with the absence of a debris-like smear layer; enamel prisms and opening of dentinal tubules were recognised. Surface roughness was significantly increased with the laser system. Microleakage test revealed no significant differences between the laser and bur cavities. Crosscut sections of the cavities with no microleakage showed no gap at the interface. Laser cavity may facilitate good adaptation of composite resin with enamel and dentine, because an increase of surface roughness and the openings of dentinal tubules may facilitate the formation of a hybrid zone, since a primer and an adhesive can penetrate the surface better when the smear layer is removed. It can be concluded that shallow cavity prepared by Er:YAG laser is capable of decreasing microleakage of composite resin restorations, and its efficiency is similar to etched bur cavities.

The aim of this study was to compare the microleakage behaviour of three restorative materials using the autoradiographic method. The study was accomplished in vitro using freshly extracted human molars and a Ca45 radioisotope and autoradiography. Twenty-seven molar teeth were divided into three experimental groups of seven specimens each. Class II cavities were prepared at the mesio-occlusal aspect and restored with amalgam and two different composite resins. The restorations were finished, thermocycled and tested for microleakage, using the Ca45 radioisotope. The results were analysed using the Kruskal-Wallis analysis test. Amalgam exhibited more leakage compared with composite resins. However the differences among the leakage behaviours of three filling materials were not statistically significant (P=0.064).

Aim: This in vitro study evaluated the microleakage of root fillings involving four root-canal sealers including AH Plus (De-Trey, Switzerland), RoekoSeal (Roeko, Germany). Ketac-Endo (ESPE, (Germany) and Sultan (Sultan Chemists, USA., Methodology: Forty extracted human maxillary anterior teeth were used. The coronal part of each tooth was removed and the root canals were prepared using the step-back technique and apical enlargement to size 60 file. The specimens were randomly divided into four groups of 10 samples, filled with one of the test materials and gutta-percha cones by the cold lateral condensation technique. A fluid filtration method was used for quantitative evaluation of apical leakage. The leakage was measured by the movement of an air bubble in a capillary glass tube connected to the experimental root section. Measurements of fluid movement were made at 2-min intervals for 8 min. Water transport through existing voids in the obturated canals could be measured reproducibly in this way. The quality of the seal of each specimen was measured after 7,14 and 21 days., Results: Statistical analysis indicated that all the root fillings showed less leakage after 21 days (P < 0.05). Fillings incorporating Sultan showed significantly more leakage than all other sealers., Conclusions: Root fillings with RoekoSeal in combination with cold lateral condensation technique showed better sealing than those with Ketac-Endo, AH Plus and Sultan sealers after 21 days. The fluid filtration test used in this study gave quantitative results and allowed nondestructive long-term evaluation of specimens.

This in vitro study evaluated the influence of the cavity size of restoratives on a new electrical method for detecting marginal leakage. Cavities were prepared on the buccal coronal and root surfaces of 32 extracted non-carious human molars and were divided into four groups having different cavity depths (0.5 approximately 4.0mm) or margin sizes (long axis or diameter: 2.0 approximately 4.0mm). All cavities were filled with resin composites without a bonding system. After physiological saline was applied, then wiped off, the change in conductance was measured continuously across the margin from the composite surface to the tooth surface. Conductance was measured at the same location after filling and before cavity preparation. In coronal and root surface cavities, the change in conductance after filling increased as the depth of cavity increased. There were significant differences in the change of conductance among the three groups with different cavity depths (p < 0.05). The differences between large and small cavity margin groups were not significant for either surface cavities. This method was shown to discriminate between deep and shallow marginal leakage, with the detection of marginal leakage being independent of margin size.