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Purpose: To assess the sealing properties of four luting materials used for cementation of full cast crowns., Methods: 40 human premolars were prepared with a chamfer finish line. Stone dies were fabricated and copings were waxed, invested and cast in gold. Ten samples (n = 10) were randomly assigned to four groups. In two groups, resin modified glass-ionomer cements were used, ACTIVA BioACTIVE-CEMENT/BASE/LINER and FujiCem2; the third group received the self-adhesive resin cement Embrace WetBond, while the fourth group served as control with a zinc phosphate cement. After cementation, excess cement was removed followed by bench-set for 10 minutes. All samples were stored in water at 37 degrees C and subjected to thermal cycling (x2000 between 5 and 55 degrees C). Subsequently the occlusal surface was reduced exposing the dentin. After sterilization the specimens were subjected to bacterial microleakage with E. faecalis in a dual chamber apparatus for a period of 60 days. Bacterial leakage was checked daily. Data were analyzed using the Kaplan-Meyer survival test. Significant pairwise differences were analyzed using the Log Rank test and the Fishers' exact test at P < 0.05., Results: ACTIVA BioACTIVE-CEMENT/BASE/LINER, FujiCem2 and Embrace WetBond showed the lowest microleakage scores and differed statistically significantly (P < 0.05) from zinc phosphate cement.

Purpose: To determine the bond strength, nanoleakage and interfacial morphology of four self-etch adhesives bonded to superficial dentin., Methods: Microtensile (MT) (n= 15) and single plane shear (SP) (n= 8) bond tests were performed using human dentin polished through 320-grit SiC paper. Clearfil Protect Bond (PB), Clearfil S3 Bond (S3), Prompt L-Pop (PLP) and G-Bond (GB) were used according to their manufacturers' instructions. Composite was applied as cylinders with a thickness of 4 mm with a 1 mm diameter and stored in water at 370C for 24 hours. Specimens were debonded with a testing machine at a cross-head speed of 1 mm/minute. Means and standard deviations of bond strength were calculated. Data were analyzed using ANOVA. Fisher's PLSD intervals were calculated at the 0.05 level of significance. Failure modes were determined at x100. The hybrid layer was revealed by treatment with 5N HC1/5% NaOCl or fractured perpendicular to the interface and sputter coated with gold. Specimens were viewed at x1,000, x2,500, and x5,000 in a field emission SEM at 15 kV. Teeth (n=2) sectioned into 0.9 mm-thick slabs were immersed in ammoniacal silver nitrate solution for 24 hours, rinsed and immersed in photo-developing solution for 8 hours. Specimens were sectioned (90 nm-thick) and observed under TEM., Results: Means ranged from 25.0 to 73.1 MPa for MT and from 15.5 to 56.4 MPa for SP. MT values were greater than SP, but were highly correlated (R2 = 0.99, P= 0.003) and provided the same order for the systems studied. Fisher's PLSD intervals (P< 0.05) for bond strength techniques and adhesives results were 1.7 and 2.3 MPa, respectively. Failures sites were mixed. TEM showed that hybrid layers were -0.5 pm for PB, GB and S3 and approximately 5 microm for PLP. SEM showed morphologic differences among adhesives. Silver nitrate deposits were observed within the interfaces for all adhesive systems.

Purpose: To evaluate the microleakage of Class II cavities restored with experimental low-shrinking resin composites proposed for bulk filling and to measure their microtensile bond strength (microTBS) to dentin and compare to those of previously marketed low-shrinkage composites., Methods: Class II cavities (7 mm occluso-gingival height, 2 mm mesio-distal depth of the box, 4 mm occlusal depth, 4 mm bucco-lingual width) were prepared in 50 molars and randomly divided into five groups (n = 10), according to the material: SureFil SDR flow (SDR), Filtek Silorane (FS) and experimental materials (G-aenial Flo bulk fill, GF; G-aenial Universal Flo bulk fill, GUF; GC Kalore bulk fill, GK). Microleakage was separately assessed at enamel and dentin margins by scoring the depth of silver-nitrate penetration. Twenty teeth divided into five groups (n = 4) were selected for microTBS testing. The same materials as for microleakage assessment were placed in bulk to mid-coronal dentin. Microtensile beams were loaded in tension, and microTBS at failure was calculated in MPa. Microleakage and microTBS data were analyzed by ANOVA on ranks, followed Dunn's post hoc test (P< 0.05)., Results: Microleakage was not observed at the enamel interface in any of the groups. At the dentin interface, SDR recorded significantly higher microleakage than the other materials. microTBS of GF, GUF and GK did not differ among each other (33 +/- 12 MPa, 31 +/- 11 MPa, 30 +/- 9 MPa, respectively), while SDR (63 +/- 17 MPa) and FS (55 +/- 17MPa) achieved significantly higher microTBS values. No direct association between the sealing properties and the bond strength values was observed.

Purpose: To evaluate if hydrostatic pulpal pressure plays a role in reducing microleakage., Methods: Uniform Class 5 preparations were accomplished on human molars with one margin on root dentin. Prepared teeth were randomly placed in one of three groups: (1) Hydrostatic pressure simulation at 20 cm pulpal pressure; (2) Hydrostatic pressure simulation but no pressure applied (positive control); and (3) Conventional microleakage method. Specimens were subjected to 24 hours methylene blue dye, sectioned, and microleakage assessed as a function of microleakage length versus entire preparation wall length using a traveling microscope., Results: Hydrostatic pressure specimens demonstrated less gingival wall microleakage than the control groups while no difference was found between occlusal preparation walls.

Purpose: To evaluate the influence of dentin moisture on bond strengths of an etch-and-rinse bonding agent to primary dentin clinically and in the laboratory., Methods: The sample consisted of two groups of 20 caries-free primary second molars: molars in exfoliation period (clinical group) and extracted molars (laboratory group). Class I cavities were prepared in all specimens leaving a flat dentin surface on the pulpal floor. A two-step etch-and-rinse adhesive was vigorously rubbed on either dry (n = 5) or wet demineralized dentin (n = 5) under clinical or laboratory conditions. After restorative procedures, the teeth from the clinical group were extracted after 20 minutes. All samples were processed and underwent microtensile bond strength test and silver nitrate uptake evaluation under scanning electron microscopy., Results: Statistically higher bond strength values were observed when the bonding was performed under laboratory conditions and on a wet demineralized dentin. Most of the failures were adhesive and mixed irrespective of the experimental condition. Silver nitrate uptake occurred in all groups irrespective of the experimental condition. Resin-dentin bond strengths produced in the laboratory in primary teeth may overestimate those produced under clinical circumstances.

Purpose: To study the effect of acid etching and the application of a hydrophobic bonding resin on the microtensile bond strengths (microTBS) and marginal sealing of the 1-step self-etch adhesive Adper Easy Bond (AEB)., Methods: Middle dentin was exposed in 30 extracted molars and randomly divided into six groups: (1) AEB applied as per manufacturer's directions; (2) as in AEB, but one coat of hydrophobic resin (HR) was applied and cured over AEB (AEB+HR); (3) etching with 35% H3PO4 for 15 seconds followed by AEB (Etch+AEB); (4) as in group Etch+AEB, but one coat of HR was applied and cured over AEB (Etch+AEB+HR); (5) Adper Single Bond Plus, the 2-step etch-&-rinse adhesive control (ASB); (6) Adper Scotchbond Multi-Purpose, the 3-step etch-&-rinse adhesive control (SBMP). Buildups were constructed with Filtek Z250 and cured in three increments of 2 mm each. Specimens were sectioned with a slow-speed diamond saw under water in X and Y directions to obtain bonded sticks with a cross section of 0.8 +/- 0.2 mm2 and tested to failure in tension mode at a crosshead speed of 1 mm/minute. Statistical analyses were computed using one-way ANOVA followed by Duncan's post-hoc test at P<0.05. For marginal sealing, 36 Class V preparations were restored with one of the six adhesive combinations and processed with 50% ammoniacal silver nitrate. After sectioning, specimens were observed under a backscattered FE-SEM to evaluate silver infiltration into the resin-dentin interface, which was measured in ranks (0-4) and compared with non-parametric statistical tests (P<0.05)., Results: AEB resulted in statistically lower mean microTBS than all other groups at P0.05. All the remaining groups resulted in statistically similar mean microTBS. For marginal sealing, data were grouped in three statistical subsets: Groups AEB and AEB+HR resulted in statistically less silver infiltration than groups Etch+AEB and Etch+AEB+HR. Groups ASB and SBMP resulted in similar silver infiltration compared to Groups AEB and AEB+HR. The nanoleakage pattern consisted of agglomerates of silver deposits located predominantly in the hybrid layer, while reticular or water-tree silver deposits were observed in both the AEB and ASB adhesive layers.

Purpose: To test if the hybrid layer formation by Hybrid Root SEAL (Sun Medical Co.), a 4-META-containing auto-adhesive self-etching root canal sealer, is affected by the sequence of irrigants employed for removing canal wall smear layers during root canal treatment., Methods: Single-rooted teeth were shaped and irrigated with EDTA as initial rinse/NaOCl as active final rinse (Group 1), or NaOCl as initial rinse/EDTA as active final rinse (Group 2). All canals were obturated with Hybrid Root SEAL using a single-cone technique. Root slices derived from the coronal, middle and apical thirds of the roots were processed for transmission electron microscopy after removing the gutta-percha, leaving the sealer intact. Additional filled canals from the two groups were evaluated for fluid leakage., Results: Hybrid layer was absent in Group 1 and was present only when a collagen matrix was produced by EDTA demineralization (Group 2). Significantly more leakage (4.03 +/- 1.94 microL min(-1) vs. 1.50 +/- 0.42 microL min(-1); P < 0.05) was observed in the absence of dentin hybridization.

Purpose: To examine the effects of collagenase and esterase activity on the microtensile bond strength and nanoleakage at the resin-dentin interfaces of two adhesive systems: a total-etch adhesive (Single Bond 2: SB) and a self-etch adhesive (Clearfil SE Bond: SE)., Methods: Resin composites were bonded to the occlusal dentin surfaces of extracted human premolars with either SB or SE. The bonded teeth were sectioned into beams and assigned to one of four storage conditions: phosphate buffer solution (24 hours), phosphate buffer solution (4 weeks), collagenase solution (4 weeks), or esterase solution (4 weeks). Microtensile bond strength was evaluated and analyzed by two-way ANOVA. Failure mode was analyzed under SEM, and nanoleakage was examined with TEM., Results: The bond strength of SE was superior to that of SB after 4-week storage in three aqueous solutions. Collagenase and esterase solutions did not decrease the bond strength of SB any more than the phosphate buffer solution (P > 0.05). In regard to SE, the bond strength after 4-week storage in collagenase solution was lower than in the phosphate buffer solution (P < 0.05). TEM images revealed increasing tendency of nanoleakage in the bonded interfaces after storage in collagenase and esterase solutions.

Purpose: To investigate the optimal silver nitrate concentration and tooth immersion period for assessing marginal leakage at the sealant-enamel interface, using micro-CT., Methods: Two experiments were conducted, using eight teeth sealed with a resin composite without etching, in dried but not desiccated, pits and fissures. Five teeth were immersed in 50% silver nitrate for 0, 1, 2, 3, and 4 hours and scanned, using micro-CT, and two evaluators using a newly developed index assessed marginal leakage at the sealant-enamel interface (Experiment A). Experiment B was carried out in the same way as Experiment A, with the difference that teeth were immersed in 50% and 60% silver nitrate for 2 and 3 hours. Reliability of scores was estimated, using weighted kappa coefficient. ANOVA and t-test were applied to test for period and concentration effects., Results: Reliability of collected data was substantial. A statistically significant difference was observed between 50% silver nitrate penetration scores at 0-1 and 2-4 hours of immersion (P < 0.0001) but not between 50% silver nitrate penetration scores at 2-, 3-, and 4-hours of immersion (P > 0.05) (experiment A). Analysis in experiment B showed a period effect (P = 0.03) but no concentration (P = 0.07) and interaction effect (P = 0.64). Combining all data from 50% silver nitrate immersion, analysis showed no statistically significant difference in penetration scores between 2, 3 and 4 hours of immersion (P = 0.33). The newly developed index showed substantial reliability.

Purpose: To examine the ultrastructure and silver nanoleakage of the resin-dentin interfaces in sound and caries-affected primary tooth dentin bonded with a 4-META one-step self-etch adhesive., Methods: Each of five sound and carious primary molars was bonded with Hybrid Bond. Resin-dentin interfaces were observed with TEM micrographs obtained from silver-impregnated, unstained and undemineralized sections of bonded sound and caries-affected primary dentin, and stained and demineralized sections of bonded sound and caries affected primary dentin without silver impregnation., Results: For sound dentin, silver nanoleakage was observed extensively in the patent dentin tubules, within the dentin beneath the hybrid layer, within the hybrid layer in some specimens, and as water trees that partially protruded into the overlying adhesive layer. The hybrid layer was about 1 microm thick. Smear plugs in the dentin tubules and smear on the ground dentin protruded in the hybrid layer. Remnants of demineralized smear were observed overlying the adhesive layer. For caries-affected dentin, the hybrid layer was obscure. Dentin tubules were occluded with mineral deposits. There were no water trees or nanoleakage in the adhesive layer or hybrid layer. However, smear remnants were observed in the adhesive layer and large silver deposits were observed in the highly porous underlying caries-affected dentin.

Purpose: To evaluate the effect of different air-abrasion devices on substance loss on flattened enamel, preparation extent, and microleakage of invasive pit and fissure sealings., Methods: 150 freshly extracted caries-free human third molars were used. 60 teeth (n = 10) were embedded, enamel surfaces were polished to #1200, and six air abrasion devices abraded specimens for 5 seconds. Substance loss was profilometrically recorded as maximum and mean width, and maximum and mean depth. From 90 intact teeth (n = 10), fissures were enlarged by air abrasion (Rondoflex 27 microm/50 microm, Airsonic Mini Sandblaster, CoJet Prep, PrepStart, Primus CPE), or treated with a diamond bur (De Craene), or using a metal bur (Fissurotomy Micro NTF), or with oscillating diamond tips (SONICSeal). Prepared fissures were etched and rinsed and sealed with a light-curing sealant (Helioseal). After four weeks water storage and subsequent 2,000 thermocycles (5 degrees C/55 degrees C), microleakage was assessed with 5% methylene blue for 3 minutes at 30G on cross cuts at x40 magnification. Furthermore the parameters upper fissure width, prepared and unprepared area, penetration depth of the sealer, and area of voids were recorded., Results: For substance loss on flattened enamel, CoJet Prep and Mini Sandblaster revealed the widest abrasion areas, PrepStart produced the deepest craters (P < 0.05). Regarding preparation characteristics, rotary burs and PrepStart caused significantly less substance loss than the other devices (P < 0.05). Due to the etch&rinse approach, microleakage was generally minimal. Only after air abrasion with Rondoflex (50 microm) significantly less complete sealings were recorded (P < 0.05).

Purpose: To evaluate the quality of the interface of sound and carious primary tooth dentin bonded with two 4-META one-step self-etch adhesives., Methods: 12 sound and 12 carious primary molars were bonded with AQ Bond Plus (AQBP; Sun Medical) or Hybrid Bond (HB; Sun Medical) and restored with Clearfil Protect Liner F (Kuraray Medical Inc.). After 24 hours of water immersion, the teeth were sectioned and polished. Resin-dentin interfaces were measured with a nano-indentation tester and hardness and Young's modulus were calculated. Data were analyzed using one-way or two-way ANOVA and Fisher's PLSD test with alpha = 0.05. Resin-dentin interfaces were also observed with SEM and TEM. Ammoniacal silver nitrate was used as a tracer for TEM observation., Results: Hardness and Young's modulus of the interfacial dentin were significantly lower than the underlying intact dentin except for the carious-AQBP group. However, there was no significant difference of hardness and Young's moduli of the interfacial dentin among all groups. TEM revealed extensive interfacial nanoleakage in sound dentin bonded with either AQBP or HB. For the carious teeth, nanoleakage was absent in the hybrid layers bonded with the two adhesives. However, extensive silver deposits were identified from the subsurface, porous caries-affected dentin.

Purpose: To assess the contact angle, volume loss and nanoleakeage profile of five one-component self-etching adhesive formulations that differed in their HEMA content, on enamel and dentin., Methods: Contact angles of drops from each adhesive system were measured over 40 enamel and dentin flat surfaces. Volumetric changes were measured as well. The adhesives were then applied over repolished surfaces according to manufacturers' recommendations, covered with a microfilled restorative composite and the samples were silver infiltrated and prepared for evaluation in a scanning electron microscope., Results: On enamel and dentin surfaces, the contact angles decreased with increasing HEMA content. A correlation was observed between contact angle, volume loss and HEMA content on both substrates.

Purpose: To assess the apical sealing property of a new root canal filling material, Epiphany., Methods: Seventy extracted maxillary and mandibular single-rooted teeth were used. They were randomly divided into three groups and obturated by lateral condensation with gutta-percha and AH 26/AH Plus sealers and Resilon core material and Epiphany sealer. Apical leakage was measured by the fluid-transport method., Results: The differences in leakage among gutta-percha with AH 26, gutta-percha with AH Plus, and Resilon with Epiphany were statistically significant (P < 0.05). The teeth filled with gutta-percha/AH 26 displayed the most apical leakage. There were no differences between the Resilon/Epiphany and gutta-percha/AH Plus groups (P > 0.05).

Purpose: To evaluate in vitro the gingival microleakage of Class II direct and indirect composite restorations with cervical margins 0.5 mm apical to the cemento-enamel junction (CEJ)., Methods: Mesial-occusal (MO) preparations of similar size were made in 10 homologous pairs of caries-free extracted human third molars. One specimen for each pair was prepared for a direct composite restoration and the other for an indirect composite restoration. Direct preparations were restored per manufacturer's instructions. Indirect preparations were impressed, and composite restorations were fabricated and cemented with a dual-cure cement. A total-etch technique was used for all restorations. Restorations were finished, polished, stored for 1 week in distilled water at 37 degrees C, thermocycled (5 degrees-55 degrees C x 1000), sealed with fingernail polish (leaving a 1.5 mm open periphery adjacent to the gingival margin), and placed in 0.5% basic fuchsin dye for 24 hours. Teeth were sectioned longitudinally (mesio-distally) within the restoration in two cuts and the four resulting surfaces (two inner cut surfaces, two outer cut surfaces) were evaluated for dye penetration with a x10 stereoscope using a scale of 0 (no penetration) to 4 (dye penetration involving more than half the axial wall)., Results: All 20 specimens had at least one score of three (dye penetration involving less than half of the axial wall) or four. Statistical analysis (Wilcoxon paired-sample test) disclosed a significant decrease in the indirect composite microleakage scores for the two outer cuts (P = 0.006, P = 0.002). No significant differences in microleakage scores were found between materials for the inner cut surfaces of the specimens. Overall, the results of die penetration showed no statistical difference between Class II direct and indirect composite restorations for microleakage.

Purpose: To assess the effects of the highly reactive molecule of ozone on sound enamel physical properties and its effects on sealing ability., Methods: The effect of ozone on sealant tag length, microleakage and unfilled area proportion were evaluated on intact and prepared sound molar fissures. Microhardness, contact angle and acid resistance tests were performed on ground sound smooth surfaces. The samples were treated with ozone for 40 seconds (HealOzone). Control samples were treated with air (modified HealOzone) or left untreated., Results: No statistically significant difference was observed between the control and ozone treated samples in all tests. Prepared fissures exhibited no unfilled areas and a statistically significantly lower microleakage compared to intact fissures. Ozone was shown to dehydrate enamel and consequently enhance its microhardness, which was reversible.

Purpose: To evaluate the effect of a vibrating probe on sealant penetration into pits and fissures., Methods: Thirty-six extracted human third molars were used. The occlusal surface of each molar was cleaned with a rubber cup and pumice slurry. Scotchbond Etchant (35% phosphoric acid gel) was applied to the occlusal fissures of each molar for 20 seconds. Fissures were then sealed as follows: Group 1: Concise Light Cured White Sealant was applied without vibration; Group 2: same as in Group 1 but with vibration; Group 3: Single Bond Adhesive was applied, then Concise Light Cured White Sealant was applied without vibration; Group 4: same as in Group 3, but sealant was applied with vibration; Group 5: Concise Light Cured White Sealant was applied without vibration, then Z-100 composite was burnished over the sealant and light-cured; Group 6: same as in Group 5, but sealant was applied with vibration. Microvibe vibrating probe was used for sealant vibration. After 24-hour immersion in 2% basic fuchsin dye solution, specimens were sectioned, and dye and sealant penetration were scored using a stereomicroscope and color slides. Selected sectioned samples were observed under the SEM., Results: No statistically significant differences between the groups were observed for either dye or sealant penetration scores. In all groups, sealant penetration was more influenced by the shape, depth and residual debris of fissures than by the use of a vibrating probe.

Purpose: To evaluate microleakage around Class V resin-based composite restorations in box-shaped cavities with and without marginal bevels, bonded with one of seven self-etching materials and a non-self etching system., Methods: 120 extracted human premolars were randomly assigned to eight groups for bonding with the following self-etching agents: Prompt-L Pop, Adper Prompt, Clearfil SE, Prime& Bond NT with NRC, Xeno111, One-Up Bond, AdheSe, or Prime & Bond NT using a total etch technique (36% H2PO4). Box cavities were cut in both the lingual and buocal surfaces. The cavities were made with an ISO 010-fissure diamond bur in a water-cooled high-speed handpiece and were approximately 3 mm wide, 1.5 mm deep, and 2.0 mm high. Selected at random, box-shaped cavities were cut with a 0.5 mm bevel in enamel and dentin on one side and on the contra-lateral side, box-shaped cavities were cut without bevels. Each tooth served as its own control. The teeth were thermocycled and the specimens prepared and examined for microleakage using Procion Red as a marker., Results: All gingival margins leaked whether or not a bevel had been placed, when bonded either with a self-etching agent or using a total etch technique with 36% phosphoric acid. There was no significant difference in leakage between the self-etching groups or those using a total etch technique, at the gingival bevel margins, (P= 0.7384) or the gingival non-beveled margins (P= 0.2307; Kruskal-Wallis Test). Microleakage was found with every agent, both occlusally and gingivally, when bonded either with a self-etching agent or using a total-etch technique. There was no significant difference in leakage between the self-etching groups or those using a total etch technique at the enamel bevel margins, (P= 0.9907) or the enamel non-beveled margins (P= 0.9963; Kruskal-Wallis Test).

Purpose: To evaluate the effect of different polymerization techniques on microleakage and gap formation of resin-based composite restorations. One correlation test was also carried out between these methodologies., Methods: 180 vertical slot cavities were prepared in bovine teeth and filled with Z250/Single Bond system, for the following six groups (n=30): Soft-start I - 10 seconds at 75 mW/cm2 + 30 seconds at 560 mW/cm2; Soft-start II - 10 seconds at 190 mW/cm2 + 30 seconds at 560 mW/cm2; Pulse delay - 3 seconds at 300 mW/cm2 + 5 minutes waiting + 30 seconds at 560 mW/cm2; Plasma arc - 3 seconds at 1,500 mW/cm2; High intensity - 40 seconds at 810 mW/cm2; Conventional (control) - 40 seconds at 560 mW/cm2. After polishing, epoxy replicas were prepared for electron microscopy analysis (n=10), at x500 magnification. The samples were thermocycled, new epoxy replicas were prepared, and the teeth were immersed in 2% methylene blue dye solution for 4 hours. Marginal gaps were evaluated again and the microleakage was assessed., Results: No statistical difference among polymerization techniques was observed for microleakage (Kruskal-Wallis test). For gap formation there was no statistical difference among polymerization techniques either before or after thermocycling (Tukey test). Conversely, thermocycling significantly increased the gap formation for all groups. No correlation (Spearman correlation test) was observed for the results of microleakage and gap formation.

Purpose: To compare nanoleakage patterns of an unfilled (OS; One-Step), a 6 wt% spherical silica-filled (OSs; One-Step Plus) and a 15 wt% glass-filled (OSg) version of a two-step, acetone-based self-priming adhesive. Permeability of bonded dentin treated with OS and OSs was also examined., Methods: Deep, coronal dentin from extracted third molars were etched and bonded using these adhesives. One-mm thick sections were immersed in 50 wt% ammoniacal silver nitrate (pH 9.5) for 24 hours. Unstained, undemineralized sections were examined by TEM. The permeability of dentin bonded with OS and OSs were investigated at 20 cm of H2O hydrostatic pressure and compared with the osmotic conductance determined with 4.8 M CaCl2 at zero hydrostatic pressure. Composite-dentin beams bonded with OS, OSs and OSg that were fractured after microtensile bond testing were examined by SEM., Results: Two types of nanoleakage patterns were recognized along the resin-dentin interfaces. The reticular type consisted of discontinuous islands of silver deposits and was exclusively seen in hybrid layers. The spotted type consisted of isolated silver grains and was evident throughout the hybrid and adhesive layers in OS. These two patterns were seen to variable extents in the two filled adhesive versions OSs and OSg and their distribution was independent of one another. OS and OSs bonded dentin were permeable to fluid filtration. However, part of this fluid movement was due to the permeability of the adhesive layer, as demonstrated by osmotic fluid conductance in the absence of hydrostatic pressure. Fractographic analysis revealed denuded collagen fibrils within fractured hybrid layers that were indicative of incomplete resin infiltration.

Purpose: To evaluate the efficacy of differing resin based liner materials in reducing microleakage., Methods: 80 freshly extracted caries-free human premolars and molars were used. MO/DO Class II standardized preparations were performed with the gingival margin placed 1 mm above the CEJ. Teeth were randomly divided into two groups; each one was divided into four subgroups (A-B-C-D for Group 1 and E-F-G-H for Group 2). Each prepared tooth was etched with 32% H3PO4 (Uni Etch); in Group 1, one coat of One Step and in Group 2, two coats and two cures of Prime & Bond NT adhesives were applied. In each group 1 mm layer of three different liners was used: A2 Heliomolar RO for A and E; A2 Heliomolar Flow for B and F; A2 Bisfil 2B for C and G. No liner was used for D and H subgroups. Teeth were then restored using 2 mm increments of Pyramid A2 Dentin and A1 Enamel and cured with a VIP curing light. Teeth were thermocycled x500 between 5 degrees C and 55 degrees C with a dwell of 30 seconds and then placed in a 0.5% methylene blue dye solution for 24 hours at 37 degrees C. Samples were sectioned longitudinally and evaluated for microleakage at the gingival margin under a stereomicroscope at x20 magnification. Dye penetration was scored using an Ordinal Scoring System where 0= no penetration; 1= enamel penetration; and 2= dentin penetration., Results: A Chi Square Test revealed a statistically significant difference between Group 1 and Groups 2 (P < 0.001). Group 1 yielded the most microleakage. No statistically significant difference was noted between the subgroups of each group; a statistically significant difference of B and D vs. E and H (P < 0.01 > 0.001) and B vs. G and D (P < 0.05 > 0.01) was also noted. The dentin bonding agent in Group 2 contributed to a reduction of microleakage when compared to Group 1.

Purpose: To determine the bond strength of five adhesives systems to either superficial or deep dentin., Methods: Extracted human third molars had their crowns transversally sectioned either next to the occlusal DEJ or next to the pulp, to expose flat, superficial or deep dentin surfaces. The surfaces were bonded with: 1) three two-step, total-etch, self-priming adhesives (Single Bond, Prime&Bond NT, and Excite), 2) a two-step, self-etching primer (Clearfil SE Bond), and 3) a single-step, self-etching all-in-one adhesive (Etch & Prime 3.0) according to manufacturers' directions. Composite build-ups were constructed incrementally with Z250. After storage for 24 hours in water at 37 degrees C, the teeth were sectioned to obtain several bonded beams of 1.0 mm2 cross-sectional area. Each beam was tested in tension in an Instron machine at 0.5 mm/minute. Results were analyzed by two-way ANOVA and post-hoc multiple comparisons (P = 0.05). Bonded interfaces were also examined by TEM. Nanoleakage was examined using a silver-staining technique., Results: Single Bond, Prime&Bond NT and Clearfil SE Bond performed equally when were bonded to superficial dentin; the lowest value was obtained with Etch & Prime 3.0. On deep dentin, the highest bond strengths were attained with Clearfil SE Bond and Prime & Bond NT. The bond strengths of Prime & Bond NT and Excite were significantly higher to deep than to superficial dentin and the rest of the adhesives showed similar bond strength to both dentin depths. Nanoleakage was manifested to variable extent within all hybrid layers examined.

Purpose: To evaluate the microleakage of a condensable resin composite using a microhybrid flowable composite as a liner, cured with four different methods of polymerization., Methods: 40 freshly extracted caries-free human premolars and molars were used. MO/DO Class II standardized preparations were performed with the gingival margin placed 1 mm above the CEJ. Teeth were randomly divided into four groups. Group 1 (control group): conventional mode (Elipar Highlight), Group 2: step mode (Elipar Highlight), Group 3: ramp mode (Elipar Trilight) and Group 4: pulse mode (VIP). Preparations were etched with 32% phosphoric acid (Uni-Etch) and an adhesive system (One-Step) was used according to the manufacturer's instructions. Teeth were then restored using a 1 mm layer of flowable composite (A2 AEliteflo LV) on the gingival and pulpal floor and condensable composite (Pyramid A2 Dentin and A1 Enamel) in 2 mm increments. Teeth were thermocycled x500 between 5 degrees C and 55 degrees C with a dwell of 30 seconds and then placed in a 0.5% methylene blue dye solution for 24 hours at 37 degrees C. Samples were sectioned longitudinally and evaluated for microleakage at the gingival margin under a stereomicroscope at x30 magnification. Dye penetration was scored using an ordinal scoring system as 0: no penetration; 1: enamel penetration; 2: dentin penetration., Results: A Mann-Whitney U Test revealed a statistically significant difference between Group 1 with Groups 2, 3 and 4 (P < 0.001). Group 1 yielded the most microleakage. No statistically significant difference was noted between Groups 2, 3 and 4.

Purpose: The purpose of this study was to determine the relationship between polymerization contraction stress and leakage in Class V composites., Methods: A microfill (Heliomolar) and two minifill hybrid composites (Herculite, Z100) were tested. Maximum contraction stress (n = 5) for the composites was evaluated in a MTS machine at a C-factor of 3 (ratio of bonded to non-bonded surface area). Composite was placed in the gap between the surfaces of glass stubs that had been air abraded, silane treated and coated with a layer of resin adhesive. Specimens were light-cured through the top glass stub for 60 seconds and maximum force was recorded during the first 10 minutes. Leakage (n = 10) was evaluated by cutting cylindrical cavity preparations with all enamel margins (C-factor = 3) in bovine incisors. The cavities were treated with two layers of Scotchbond MP adhesive. Composites were applied in one increment, light-cured at the same intensity used in the stress tests, and immediately finished on SiC paper. After 1 day in water, the restorations were placed in silver nitrate, developed and evaluated as a single cross-section (2-D) and multiple cross-sections (3-D) for leakage: 0 (none), 1 (minimal leakage), 2 (to the DEJ), 3 (to line angle), 4 (along the pulpal wall)., Results: The maximum stresses (MPa) recorded were lowest for Heliomolar (7.0 +/- 0.4), intermediate for Herculite (10.5 +/- 0.6) and greatest for Z100 (11.6 +/- 1.3). 3-D leakage was as follows: Heliomolar--two specimens scored 1, seven scored 2 and one scored 3; Herculite--six scored 2 and four scored 3; Z100--eight scored 3 and two scored 4. The Kruskal-Wallis test showed a significant difference in leakage for the three composites (P < 0.05), and leakage was greater when evaluated in 3-D. The leakage results correlated with the stress values, i.e. composites with higher contraction stress showed more extensive marginal leakage.

Purpose: To investigate the effect of a low-viscosity resin-based composite (LVC) liner on the microleakage of cervical resin-based composites bonded with new adhesive systems., Methods: 180 wedge-shaped cervical cavities on bovine incisors were treated with AQ Bond (all-in-one), ABF (experimental two-step self-etching primer containing antibacterial monomer) or Clearfil SE Bond (two-step self-etching primer) systems according to the manufacturers' instructions. Half of the treated cavities in each adhesive system were lined with an LVC (Protect Liner F) and filled with a hybrid resin-based composite (Clearfil AP-X). Ten specimens from each group were immersed in 0.5% basic fuchsin solution immediately after finishing the restorations. The specimens to be subjected to thermocycling (5-60 degrees C, 15 seconds dwell time, 5,000 cycles) or to flexural load cycling (approximately 0.5 mm labio-lingual displacement at the incisal edge, 10,000 cycles, 1 Hz) prior to immersion in the dye solution were also prepared. The teeth were sectioned through the center of the restorations and the degrees of dye penetration were scored. The data were analyzed with the Mann-Whitney U-test or the Kruskal-Wallis test (P < 0.05)., Results: The use of the LVC liner significantly improved marginal sealing of AQ Bond. However, the LVC liner could not prevent the deterioration in the marginal integrity caused by thermocycling or flexural load cycling. In the case of ABF, the use of the LVC liner showed a trend toward less microleakage. For Clearfil SE Bond, the LVC liner prevented the deterioration in the marginal seal caused by thermocycling.

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.

Purpose: To evaluate the effect of the cavity configuration factor (CF) on the marginal microleakage of cervical restorations with four aesthetic restorative materials., Materials and Methods: Conventional cavities, 2.9 mm in diameter and 1.5 mm deep, with CF=2.7 and "saucer"-shaped ones with CF=2 were created in 60 extracted premolars. The following groups were established: G1: Z100/Single Bond, G2: Freedom/Stae, G3: Vitremer/Primer and G4: Durafill/Durafill Bond, following each manufacturer's directions. Thermocycling of the specimens was performed in an aqueous solution of 2% buffered methylene blue, with the temperature varying between 5 to 55 degrees C, for a total of cycles of 60 minutes per day, for 7 days. The specimens were then sectioned and evaluated by two observers using photographs acquired from a stereomicroscope. The values were subjected to Kruskal-Wallis analysis and the Dunn and Wilcoxon test., Results: The averages of the microleakage scores observed in the conventional and "saucer"-shaped cavities were respectively: G1: 0.66/0.46; G2: 0.92/0.69; G3: 1.8/1.86; G4: 3.54/2.3.

Purpose: To evaluate microleakage at the dentin margins of Class II resin-based composite restorations using four simplified adhesive systems: Etch & Prime 3.0, Prime & Bond NT, Clearfil Liner Bond 2V and Clearfil SE Bond, upon thermal and mechanical stresses., Materials and Methods: Forty slot preparations (5mm x 3mm x 1.5mm) were cut in sound human molars with gingival margins below the cement/enamel junction. All adhesive systems were applied strictly according to manufacturers' instructions. Cavities were restored using Clearfil AP-X composite resin. After finishing and polishing, teeth were submitted to thermal (x700, 5-55 degrees C, 60-second dwell time) and consecutively mechanical cycling (100,000 cycle; 8 Kgf load). Specimens were coated with nail polish, immersed in silver nitrate for 2 hours and sectioned longitudinally with a diamond disc. The extent of leakage was ranked using a 0-4 scale., Results: Statistical analysis was performed using Kruskal-Wallis test. Minimal leakage occurred with Clearfil SE Bond. There was a statistically significant difference (P<0.01) between this system and Clearfil Liner Bond 2V, although the latter also showed low values of dye penetration. No statistically significant difference was found between Etch & Prime 3.0 and Prime & Bond NT. Both showed statistically greater leakage than the two other systems (P<0.01).

Purpose: To evaluate dye penetration in adhesively bonded cervical amalgam restorations., Materials and Methods: The specimens were randomly divided into four groups and the adhesives Prime & Bond 2.1, Prime & Bond 2.1 Dual Cure, Scotchbond Multi Purpose Plus and Amalgambond Plus were tested. After being restored and polished, the teeth were thermocycled 1,000 times at temperatures varying between 5 degrees C +/- 2 degrees C and 55 degrees C +/- 2 degrees C. Statistical analysis was carried out using the Kruskal-Wallis test and multiple comparisons., Results: Scotchbond Multi-Purpose Plus demonstrated lower levels of microleakage in enamel and dentin. The dual adhesives were more effective than the "one bottle" adhesive.

Purpose: To assess the marginal seal of Class II resin-based composite restorations cured by a high intensity halogen light or a plasma arc light., Materials and Methods: Class II cavities were prepared in extracted molar teeth with cervical margins located apical to the cemento-enamel junction. Cavities were restored with a posterior resin-based composite (Tetric Ceram) using either a two-increment or a bulk placement and cure restorative technique after application of bonding agent (Excite). Test parameters included light unit type/curing mode, application of flowable composite and restorative technique. After thermocycling, the teeth were immersed in basic fuchsin dye. Sectioned restorations were examined under a stereomicroscope (x 25) and extent of microleakage (mm) was recorded using an image analysis system. Data was analyzed by non-parametric statistical tests., Results: No leakage was observed at the occlusal enamel margin of a nyrestoration. Median gingival leakage values for the different test groups ranged from 0.02-2.51 mm. Light unit type had a highly significant effect on leakage (P=0.0002). The highest leakage scores were recorded with the plasma arc light used in standard curing mode and the lowest with the halogen light in turbo-boost mode.

The sealing ability of restorations is an important factor in order to prevent or reduce marginal gaps, which are often associated with postoperative sensitivity, caries and pulp disease. Usually the sealing ability of a new material is tested under laboratory conditions before being introduced on the market. However, in vitro evaluation of marginal integrity cannot predict in vivo performances of enamel-dentin bonding systems. A critical review of available data on sealing ability of last generation of adhesive-restorative materials placed on vital teeth is presented. The review includes the data of sealing performances of direct and indirect restorations, ethical considerations, influence of dental substrates on bonding, correlation between in vivo leakage studies and bond strength tests and microscopic evaluations. An in vivo protocol is presented in order to standardize leakage studies performed on vital teeth. A larger number of in vivo leakage tests are desirable in order to compare properties of new materials in multicenter studies. The ideal sequence of evaluation for new enamel-dentin bonding systems should be: in vitro tests, short term in vivo evaluations and then clinical trials.

Purpose: To investigate the microleakage associated with a hybrid resin-based composite, Tetric Ceram, bonded with the single component dentin bonding agent Excite and Ariston pHc bonded with Ariston Liner. Ariston pHc bonded with Excite and Tetric Ceram bonded with Prime and Bond NT were used as controls., Materials and Methods: Twenty-four extracted human premolars and molars were randomly assigned to four groups. Group 1: cavities were bonded with Excite and filled with Tetric Ceram. Group 2: cavities were bonded with Ariston Liner and filled with Ariston pHc. Group 3, control: cavities were bonded with Prime & Bond NT and filled with Tetric Ceram. Group 4, control: cavities were bonded Excite and filled with Ariston pHc. Cavities were cut in both the buccal and lingual surfaces. Half of each preparation was in enamel and the other was in cementum/dentin. The teeth were thermocycled at 15 degrees C for 2 s, 35 degrees C for 28 s and 45 degrees C for 2 s for 5,000 cycles after which the restorations were examined microscopically for leakage using procion brilliant red as a marker. SEM microphotographs were prepared from dye-labeled and non dye-labeled areas to illustrate the micromorphology of the systems., Results: None of the groups showed microleakage at the enamel margins. All groups showed microleakage at the gingival margins. At the gingival margin there was a significant difference between the groups (Kruskal-Wallis ANOVA, P= 0.1111.). Ariston pHc/Ariston Liner showed significantly lower microleakage scores than the other groups (Dunn's Multiple Comparison test). SEM showed that in non-dye labeled areas, Ariston pHc/Ariston Liner was in close apposition to the deeper dental tissues. The "total etch" technique resulted in a zone of demineralization. Debonding occurred at or near the top of the hybrid layer in >95% of specimens.

Purposes: (1) To evaluate the in vitro sealing ability of several Class II resin restorations whose gingival extension of the proximal margin was apical to the cemento-enamel junction and in dentin and (2) to determine the effect of thermocycling on leakage into the resin-tooth interface., Materials and Methods: Mesio-occlusal and distoocclusal preparations were made in extracted human molars. The gingival floor of the proximal box, was placed 1.0mm apical to the CEJ, and was prepared to a width of 1.5mm from the cavosurface margin to the axial wall. The teeth were restored with one of seven restorations (Z100 control, Z100, Wave, F2000, Surefil, Z100 and Vitrebond Sandwich A, Z100 and Vitrebond Sandwich B) using multiple incremental placement and materials. Following storage, half the samples were thermocycled. All 70 samples were stained using silver nitrate. The entire resin restoration was then removed from the proximal box ,and starting at the cavosurface margin the gingival floor was divided into three zones of 0.5 mm each and analyzed for dye penetration, using a novel technique which utilized the aid of computer imaging software and assessed both quantitatively and qualitatively., Results: There was no statistical difference in leakage for all groups in Zone 1. For Zones 2 and 3, the groups utilizing glass-ionomer liner on the cavosurface margin had significantly less microleakage (P>0.05). Although the compomer/hybrid combination had low leakage values on average, the wide range of values led to unpredictable results. The flowable/hybrid combination and the packable composite performed less favorably., Clinical Significance: This study demonstrated the difficulty in sealing a proximal dentin margin. However, the glass-ionomer/hybrid restorative techniques is the most likely to give successful clinical results.

Purpose: To compare the marginal sealing ability of two conventional and one polyacid-modified resin-based composite, and two conventional and three resin-modified glass-ionomers in conventional cylindrical box cavities following a silver-staining microleakage evaluation method., Materials and Methods: In 80 freshly extracted and caries-free human third molars, three standardized cylindrical butt-joint cavities were prepared: the first cavity in coronal enamel, the second at the cemento-enamel junction (CEJ) and the third completely in root cementum. A control group of 10 additional teeth was chosen. After the cavities were restored randomly using the eight restorative materials tested, the specimens were first stored in distilled water at 37 degrees C for 7 days and then thermocycled (500 cycles). Thereafter, the specimens were centrifuged for 10 min in plastic bottles containing 50 wt% silver nitrate aqueous solution. The degree of microleakage was recorded at four different depths along the restoration margins using an optical stereomicroscope equipped with a measuring gauge., Results: None of the tested systems prevented microleakage completely, but the extent of leakage decreased towards the bottom of the restorations. The resin-modified glass-ionomers performed better than the conventional resin-based composites and conventional glass-ionomers., Clinical Significance: Distinct leakage patterns were recorded among all materials investigated. Complete marginal sealing could still not be reached with the new adhesive restorative materials.

Purpose: To evaluate microleakage of Class V resin-based composites (RBC) bonded with two self-etching dentin adhesive systems. Class V cavities were restored with either one or three increments of RBC to determine whether the restorative method affected microleakage., Materials and Methods: 60 extracted human premolars and molars were randomly assigned to 6 groups for bonding with Clearfil Liner Bond 2V or Etch & Prime 3.0 or Prime & Bond NT. The latter, using a total-etch technique, was used as a control. Cavities were cut in both the buccal and lingual surfaces. Half of each preparation was in enamel and half was in cementum/dentin. The teeth were thermocycled and the restorations examined microscopically for leakage using Procion Brilliant Red as a marker. SEM microphotographs were prepared from dye-labeled and non dye-labeled areas to illustrate the micromorphology of the systems., Results: None of the groups showed microleakage at the enamel margins. All groups showed microleakage at the gingival margins. At the gingival margin, there was no significant difference between the groups irrespective of the bonding material (Kruskal-Wallis: ANOVA P=0.2113). No significant difference was observed with each material when the bulk filling (one increment) technique was compared with the three-increment technique. SEM showed that the self-etching materials produced a shallower depth of etch, and a less abundant resin tag complex than the material using a separate phosphoric acid gel. In dye-labeled areas, debonding was predominantly cohesive in resin., Clinical Significance: Gingival margin microleakage is not prevented by either restoring cavities with self-etching materials of the control using a total-etch technique.

Purpose: To evaluate the adhesive properties of a one-bottle self-etching primer system., Materials and Methods: 150 wedge-shaped cervical cavities on bovine teeth were restored with Clearfil Liner Bond 2 (LB), Clearfil Liner Bond 2V (LV) or Clearfil SE Bond (SE), according to the manufacturer's instructions. Twenty specimens of each adhesive system were finished 15 mins after light curing and 30 specimens were finished after a 24-hr storage period in water. From each group, 10 restorations were immediately immersed in 0.5% basic fuchsin solution and kept there for 24 hrs to examine microleakage. The other 10 restorations were thermocycled (5-60 degrees C, 15 s dwell time, 5,000 cycles), and then immersed in the dye solution. The remaining 10 specimens of the 24-hr storage group were subjected to flexural load cycling (0.5 mm labio-lingual displacement at the incisal edge, 10,000 cycles, 1 cps) prior to immersion in the dye solution. The data was analyzed using the Mann-Whitney U-test and the Kruskal-Wallis test. The tensile bond strengths of the adhesive systems to bovine enamel and dentin were also determined. The data was analyzed using the Student's t-test and ANOVA. In addition, SEM examinations were made to evaluate the effects of self-etching primers on enamel and dentin surfaces., Results: LV and SE showed significantly better marginal sealing than LB (P<0.05). The marginal integrity of SE did not deteriorate even after immediate finishing, thermal stresses or flexural loads. There were no significant differences in bond strengths among the adhesive systems tested. All adhesive systems showed similar bond strengths to enamel and dentin. The enamel etching patterns using LV and SE systems were obscure and difficult to assess. Although the smear plugs were not fully removed, no smear layer was observed on the treated dentin surfaces, regardless of the self-etching primer system used., Clinical Significance: Clearfil SE bond could possibly improve the clinical performance of cervical cavities.

Purpose: To evaluate the effect of cavity preparation device (i.e. carbide bur, diamond bur, air abrasive, Sonicsys, and Er:YAG laser) on microleakage of Class V resin-based composite (RBC) restorations, the tooth restoration interface and dentin ultrastructure., Materials and Methods: Eight groups (n=18) of 9 human molars each were prepared on the buccal and lingual surfaces for Class V RBC restorations using five preparation devices: Group 1: carbide bur #8 round; Group 2: diamond bur #801; Group 3: KCP 1000 air abrasion unit; Group 4: Sonicsys Approx.; Group 5: Er:YAG laser; Group 6: carbide bur plus air abrasive; Group 7: carbide bur plus laser, and Group 8: laser without etching. Circular cavity preparations, 3 mm diameter and 1.5 mm deep, were cut at the CEJ on the buccal and lingual surfaces of each tooth. A bevel was placed on the enamel margin. All cavities were restored using Single Bond adhesive system and Silux Plus according to manufacturer's directions, with the exception that no etchant was used with Group 8. After thermocycling, specimens were tested for microleakage using silver nitrate methodology. Dye penetration data was collected and subjected to non-parametric statistical analysis. SEM analysis of the dentin-RBC interface, as well as the effect of each cavity preparation device on the surface of dentin was performed., Results: Microleakage did not occur in enamel for any method of cavity preparation when the enamel was etched prior to adhesive application. Kruskal-Wallis One-way ANOVA revealed differences in dentin microleakage among the tested groups at alpha=0.05. Mann-Whitney Test for Paired Comparisons at alpha=0.01 demonstrated significantly greater dentin microleakage in Groups 5 and 7 compared to all groups except Group 3 (air abrasive). Although Group 8 had the least microleakage in dentin, this was not significantly different from Groups 1, 2, 4 and 6. SEM observation revealed hybridization at the dentin-resin interface for all groups except for Group 8 (laser prepared, non-etched). Surface analysis showed differences related to the operating mode of each preparation device., Clinical Significance: The method of cavity preparation did not affect microleakage in etched enamel. When using a laser for cavity preparation, enamel should be etched although not etching dentin may help to improve marginal seal.

Purpose: To investigate the microleakage of four hydrophilic adhesive systems: one "multiple-bottles" (Scotchbond Multi-Purpose Plus); two "one-bottle" (Single Bond, Stae); and one self-etching (Etch & Prime 3.0)., Materials and Methods: 120 bovine incisor teeth were divided into four groups (n = 30) and Class V cavities were prepared at the cemento-enamel junction. The cavities were restored with the adhesive systems and with Z100 composite. The teeth were thermocycled 1,000 times between 5+/-2 degrees C and 55+/-2 degrees C with a dwell time of 1 min, and then placed in a 2% methylene blue dye (pH 7.0) for 4 hrs, washed and sectioned vertically through the center of the restorations. The qualitative evaluation was made by three examiners who distributed pre-established scores (0-4) for each tooth using a stereomicroscope at x30 magnification., Results: In enamel margins little microleakage was observed and the Kruskal-Wallis analysis did not show differences. In dentin margins the Kruskal-Wallis and multiple comparison analyses were applied: microleakage was significantly greater with Stae (median 3) and Scotchbond MP Plus (median 4). Single Bond (median 1) and Etch & Prime 3.0 (median 2) showed the best results in dentin margins, and the statistical analysis did not demonstrate differences in microleakage among these groups.

Purpose: To evaluate whether the hybrid layer significantly contributes to the seal of adhesive Class V restorations placed in vivo and to the bond strength obtained in vitro., Materials and Methods: 20 periodontally severely compromised anterior teeth were selected for the leakage study. In each tooth, one round 3 mm wide V-shaped cavity with a maximum depth of 2 mm was prepared on the labial surface crossing the cementum-enamel junction. The sample teeth were randomly divided into two groups of ten samples each: in Group 1, Scotchbond Multi-Purpose Plus was applied in combination with Z-100 following the manufacturer's instructions. In Group 2 the bonding procedure was the same as in Group 1, except that after the phosphoric acid treatment, the cavities were treated with 5% NaOCl for 2 min. Following a period of clinical service of 60-90 days, the teeth were extracted and processed for the leakage test., Results: At the enamel site, 30% of the samples of Group 1 and 70% of the samples of Group 2 showed dye penetration. At the dentin site, 50% of the samples of Group 1 showed leakage, while all the samples of Group 2 were severely infiltrated. Statistically significant differences between the groups both for the enamel sites (P < 0.05) and for dentin-cementum sites (P < 0.001) were found. Bond strength tests were performed on 2 mm thick dentin slides of tapered Class I cavities (n = 10 in each group). The mean bond strength value obtained from cavities treated without NaOCl was 15.23 (+/-1.40) MPa and with NaOCl treatment 20.52 (+/-1.70) MPa. Statistical analysis showed significant differences (P < 0.05) between the two groups. No hybrid layer was detected on the NaOCl-treated samples by scanning electron microscopy.

Purpose: To evaluate dye penetration of proximal vertical slot resin-based composite (RBC) restorations as a function of cavity size and restorative material employed (RBC, ceramic inserts with low-viscosity resin, and RBC with low-viscosity resin liner). Microleakage was measured using rank scoring and linear measurement of dye penetration and ANOVA and non-parametric tests were used to evaluate the statistical significance of the results., Materials and Methods: Ninety erupted crack- and caries-free mandibular third molars, extracted for orthodontic reasons, were used. Proximal vertical slots were prepared on the mesial surfaces of the teeth using diamond instruments at high speed under distilled water coolant. Teeth were placed randomly into nine groups. Three sizes of diamond burs of an ultrasonic cavity preparation system were used under low energy in order to standardize cavity size and shape, each tip size being used in 30 different teeth. The gingival margins were prepared 1 mm above the cemento-enamel junction. Specimens were etched, prepared with bonding agent, restored using three different materials, and immersed in a 50% AgNO3 solution for 8 hrs and sectioned to evaluate the dye penetration., Results: Statistical analysis revealed no statistically significant differences among the nine groups.

Purpose: To evaluate the influence of three Erbium:YAG laser energies on the microleakage of Class V resin-based composite restorations., Materials and Methods: 60 extracted human premolar teeth stored in 0.12% thymol solution were randomly allocated to three groups. Buccal and lingual box-shaped Class V cavities were prepared on each tooth. One cavity served as the control and was cut using a conventional diamond bur in a high-speed handpiece. The test cavity was prepared using a pulse repetition rate of 5 Hz with 1 of 3 pulse energies; 200 mJ, 240 mJ, and 300 mJ with a 100 mJ dentin finish. The cavities were restored with Scotchbond Multi-Purpose and Z100 and were finished immediately before being stored for 3 months in thymol solution at 37 degrees C. Following thermocycling between 5 degrees C and 55 degrees C for 240 cycles and a further 12 hrs storage, the teeth were immersed in a 2% aqueous solution of methylene blue for 24 hrs. They were then sectioned through the mid-point of the restorations in a bucco-lingual plane and dye penetration was scored as 0 (none) to 4 (to the axial wall) for the enamel and dentin margins of both sections. The worst score for each margin was used for statistical analysis using the Kruskal Wallis and Mann-Whitney U tests at P < 0.05., Results: When the lased groups were compared, optimum sealing was achieved with energies of at least 240 mJ at the enamel margin and with energies no higher than 200 mJ to finish the dentin margin. However, while all the pulse energies compared favorably to the control group in enamel, a similar result was found only using the 300 mJ, with 100 mJ, finish at the dentin margins.

Purpose: To evaluate in vitro the marginal quality of Class II composite restorations at the gingival enamel margins as affected by contamination of the cavities with gingival fluid (GF) during different steps of resin bonding procedures., Materials and Methods: 70 Class II cavities were prepared in extracted human molars and restored with composite using a multi-component bonding system (OptiBond FL/Herculite XRV; OPTI) or a single-bottle adhesive (Syntac Sprint/Tetric Ceram; SYN). The cavities were contaminated with human GF: C1 after acid etching, C2 after application of the primer (OPTI) or light-curing of the primer-adhesive (SYN), and C3 after light-curing of the resin adhesive (OPTI). Uncontaminated cavities were used as the control (C0). The restored teeth were subjected to thermocycling (TC) and replicated for SEM analysis of marginal gap formation. Microleakage at the gingival margins was determined by dye penetration with basic fuchsin., Statistics: non-parametric tests (Kruskal-Wallis test, Mann-Whitney test with Bonferroni correction)., Results: In both bonding systems, contamination with GF after acid etching (C1) did not impair the marginal quality; the mean percentages of continuous margin/mean depths of dye penetration were: OPTI: C0: 88.5%/0.10 mm, C1: 95.6%/0.04 mm; SYN: C0: 90.9%/0.08 mm, C1: 97.0%/0.05 mm. Marginal adaptation was adversely affected when GF contamination was performed after

Purpose: To compare the microleakage and bond strength exhibited by two light-cured, filled dentin bonding agents, a resin cement, and cavity varnish., Materials and Methods: The four test groups of lining agents for amalgam restorations included (LF) Light-cured, Filled resin (Clearfil Liner Bond 2); (LCF) light- and chemical-cured, Filled resin (Clearfil Liner Bond + Protect Liner); (RC) Resin Cement (Panavia 21); and (V) Varnish (Copalite). For each group, 20 Class V cavity preparations were cut in human extracted molars. Tytin amalgam was condensed into the preparation. After storage for at least 24 hrs in distilled water at 37 degrees C, all restorations were subjected to 2500 thermal cycles (8 degrees C to 48 degrees C). After 1 wk, specimens were tested. For the leakage tests, teeth were immersed in 45Ca, sectioned, and radiographs of sections were evaluated and then evaluated by Ridit analysis. Retention samples were tested to failure in tension using an Instron machine and peak load (kg) was recorded., Results: Compared to varnish, the two dentin bonding agents (LF and LCF) significantly decreased microleakage at the cementum margin but not at the enamel margin. The two dentin bonding agents also exhibited significantly greater retentive strength than either the resin cement or the varnish.

Purpose: To compare microleakage of Class II hybrid resin-based composite (RBC) restorations with and without low viscosity (flowable) RBC in the proximal box., Materials and Methods: Conservative Class II cavity preparations were made in 50 extracted premolars randomly assigned to five groups (n = 10). OptiBond FL dentin bonding agent, and Prodigy hybrid RBC were used to restore all cavity preparations. Preparations in four of the five groups were restored with flowable RBC as the initial increment in the proximal box. The four flowable RBCs tested were: AEliteFlo, Revolution, UltraSeal XT and Flow-It. In the control group, the entire preparation was restored only with hybrid RBC. Specimens were stored in water at 37 degrees C for 24 hrs after restoration, thermocycled 1,000x, immersed in 2% basic fuchsin, sectioned and evaluated for microleakage. Microleakage was scored on a 0-4 scale., Results: Non-parametric Kruskal-Wallis one-way ANOVA followed by Wilcoxon signed ranks test was used for statistical analysis. The use of any of the four flowable RBCs tested did not influence microleakage significantly (P > 0.05) in Class II RBC restorations.

Purpose: To compare the adhesion of a flowable resin-based composite (RBC) vs. a condensable RBC to tooth structure using scanning electron microscopy (SEM)., Materials and Methods: Fifteen recently extracted human teeth were prepared for Class I restorations and equally divided into three groups. Group 1 was filled with Heliomolar bonded with Syntac Single Component. Group 2 was lined with Flow-It in addition to ALERT condensable RBC bonded with Bond-1 Primer/Adhesive. Group 3 was filled with ALERT bonded with Bond-1 Primer/Adhesive. All teeth were thermocycled, sectioned and evaluated for gap formation with the SEM., Results: SEM at x15 demonstrated that restorations with the flowable RBC at the tooth/restoration interface showed no evidence of marginal gaps between the RBC material or at the underlying tooth structure. A significant difference (P < 0.05) in wall adaptation was found between Groups 2 and 3.

Purpose: To evaluate the effect of direction of first cure and the presence or absence of a facial margin bevel on the adaptation of facial margins of Class III resin-based composite (RBC) restorations., Materials and Methods: Custom polyvinyl siloxane (PVS) light shields were fabricated for both the mesial and distal surfaces of 20 extracted incisors. Class III cavities were prepared in the mesial and distal surfaces of the incisors. On the facial, lingual, and gingival margins of 20 of the preparations a 0.5 mm wide enamel bevel was placed. The lingual and gingival, but not the facial, margins were beveled on the other 20 preparations. The PVS light shield was adapted to the tooth and trimmed to allow 1-2 mm of the facial margin to be exposed on 10 of the beveled and 10 of the non-beveled preparations. For the remaining 20 preparations the PVS light shield was trimmed to allow access of the curing light only from the lingual. Teeth were restored with Prisma TPH RBC. Using the appropriate shield, restorations in the facial first cure group were cured first from the facial and then from the lingual. Restorations in the lingual first cure group were cured only from the lingual. Restorations were finished flush with enamel margins and thermocycled following storage. Samples were exposed to a 50% solution of silver nitrate followed by light exposure. Teeth were sectioned and microleakage was evaluated at three levels (incisal, middle, and cervical). Four evaluators (blinded to direction of cure) independently scored microleakage using a categorical evaluation scale. Statistical analysis included non-parametric descriptive statistics, Cohen's kappa, chi-square analysis, and Kruskal-Wallis ANOVA., Results: Samples prepared without a facial bevel revealed significantly more (P = 0.01) microleakage than preparations with a facial bevel. At the most incisal level, restorations cured first from the facial revealed significantly more (P < 0.001) microleakage than restorations cured first from the lingual. At the middle and cervical levels, restorations cured first from the facial revealed significantly less (P < 0.001) microleakage than restorations cured first from the lingual. When a facial bevel was present, samples cured first from the facial showed significantly less (P < 0.001) microleakage than those cured only from the lingual.

Purpose: To compare the ability of three packable resin-based composite (RBC) systems (ALERT, SureFil, and Solitaire), placed and light-cured in either incremental layers or in bulk, to seal the gingival margin of Class II preparations when the gingival margin is placed apical to the cementoenamel junction., Materials and Methods: Packable RBCs were used to restore 60 extracted human premolars with Class II preparations using an incremental-cure technique (each layer no greater than 2 mm in thickness when light-cured) or a bulk-cure technique (n=10). Manufacturers' directions were followed; the cure technique was the only variable. After the restorations were completed, the specimens were thermocycled, stained, sectioned, and viewed under a light microscope for microleakage at the gingival margin., Results: All specimens showed leakage at the gingival margin. No statistically significant difference was found between the bulk-cure and incremental-cure techniques for each of the RBC systems evaluated. ALERT had significantly less leakage than SureFil and Solitaire.

Purpose: To evaluate the effect of plasma arc light-curing on the microleakage of Class V resin-based composite (RBC)., Materials and Methods: Facial and lingual Class V cavities were prepared at the cemento-enamel junction of extracted third molars. Restorations of the two materials (Z250; Amelogen) were placed, using the supplied dentin adhesives (Single Bond; PQ 1, respectively), and light-cured by either a halogen light curing unit (H) or a plasma arc curing unit (P). After thermal cycling, the teeth were immersed in methylene blue dye, then sections of the restored teeth were visually assessed for leakage., Results: No leakage was observed at the interface between enamel and RBC in any restoration in this study. At gingival margins, the incidence of leakage (slight/severe) was: Z250 H = 2/4, P = 6/6; Amelogen H = 3/4, P = 1/12, where n = 16. The greatest incidence of leakage was observed in restorations cured by the plasma arc method. A two-way ANOVA of leakage data rankings showed curing method to be a significant factor (P = 0.002), restorative material not to be a significant factor (P = 0.24), and no significant interaction between material and curing method (P = 0.38).

Purpose: To evaluate the effect of wet and dry bonding on microleakage of Class V restorations bonded with three filled bonding agents., Materials and Methods: Sixty extracted human premolar and molar teeth were randomly assigned to five groups for bonding with OptiBond Solo, PermaQuick PQI, Prime & Bond NT (one coat), Prime & Bond NT (two coats) and Prime & Bond 2.1, as a control material. Cavities were cut in both the buccal and lingual surfaces. Half of each preparation was in enamel and the other was in cementum/dentin. The cavities were restored with resin-based composite after the application of dentin bonding agents using a wet and dry technique for each material. The teeth were stored in distilled water for 6 days at 37 degrees C, thermocycled, and the restorations examined microscopically for leakage using Procion Brilliant Red as a marker., Results: All groups showed microleakage at both the enamel and dentin margins. At the gingival margin, there was a significant difference between the groups for wet bonding (P = 0.0349) but not for dry bonding (P = 0.9983) (Kruskal-Wallis test). There was no significant difference between the groups at the enamel margin (wet bonding: P = 0.9999, dry-bonding: P = 0.9304) (Kruskal-Wallis test). The wet-bonding technique was compared with the dry-bonding technique for each material at both the gingival and enamel margins and no significant differences were observed (in all cases P > 0.5) (Mann-Whitney U-test).

Purpose: To evaluate the effect of fatigue loading on the quality of the cement around the margins of adhesive ceramic MOD inlays., Materials and Methods: Non-metal IPS Corum porcelain inlays were made and cemented either with the resin-based composite Variolink, the compomer Dyract-Cem or the glass-ionomer cement Ketac-Cem. For each system, half of the specimens were subjected to thermal and mechanical load cycling to simulate fatigue loading. All teeth were then sectioned and evaluated by SEM on topography and by optical microscopy for dye penetration., Results: Before loading, all systems showed good marginal integrity. After loading, inlays cemented with Variolink and Dyract-Cem showed no significant (P > 0.05) increase in marginal break down, however restorations cemented with Ketac-Cem, showed a significant (P < 0.05) deterioration at the margins.