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Purpose: To evaluate the effect of different concentrations of ethylene-diamine-tetra acetic acid (EDTA) on bond strength (BS) and nanoleakage (NL) of fiber posts bonded into root canals. Materials and Methods: Seventy-two single roots were endodontically treated and divided into six groups (n = 12), according to the combination of the following factors: surface treatment (no irrigation [control], 17% EDTA, or 24% EDTA), and composite cement applied with an adhesive used in a self-etch mode (Single Bond Universal/RelyX Ultimate [SB], 3M Oral Care; Ambar Universal/Allcem [AM], FGM). After fiber post cementation, six 1-mm-thick disks were obtained for each root. Push-out bond strength (BS) was evaluated using 8 specimens per group, and the other 4 specimens were used to examine nanoleakage (NL). Data from BS and NL of each adhesive were evaluated by two-way ANOVA (surface treatment vs root region) and Tukey's test (a = 0.05). Results: The application of 17% and 24% EDTA did not influence the bond strengths of either adhesive. In general, the application of 17% and 24% EDTA increased NL values for both adhesives. Conclusion: Pre-treatment with different concentrations of EDTA was not able to improve the adhesion of fiber posts into root canals with universal adhesives. [ABSTRACT FROM AUTHOR]

Purpose: To evaluate the influence of type and viscosity of composite resins used for root reinforcement in the adhesion of glass-fiber posts to flared root canals. Materials and Methods: The crowns of 78 uniradicular permanent teeth were removed and the teeth were endodontically treated. After one week, the roots were prepared for root reinforcement and randomly divided into 6 groups (n = 13): positive control group ([PCG] the root canals were not enlarged), negative control group ([NCG] root canals were enlarged, no reinforcement), and in the remaining 4 groups, root canals were enlarged to receive root reinforcement according to a combination of the factors composite resin type (bulk-fill or conventional) and viscosity (flowable or regular). After fiber post cementation, six slices were obtained from each root (2 each from the cervical, middle, and apical thirds). For each group, 7 teeth underwent push-out bond strength testing, and 6 teeth were evaluated for nanoleakage and Vickers microhardness. Bond strength and nanoleakage data were submitted to two-way ANOVA and Tukey's test (α = 0.05), and microhardness data to one-way ANOVA and Tukey's test (α = 0.05). Results: The root reinforcement groups with regular and flowable bulk-fill composite resins showed statistically superior adhesion results (higher bond strength and less nanoleakage) compared to the negative control in all root regions. Microhardness values were higher in the cervical third followed by the middle third. Conclusion: Regular or flowable bulk-fill composite resins should be chosen for root reinforcement of flared root canals prior to fiber post cementation. [ABSTRACT FROM AUTHOR]

Purpose: To compare the the loss of retention and color match of glass-ionomer cements (GIC) and resin-based composites (RC) in noncarious cervical lesions. Other secondary outcomes (surface texture, marginal adaptation, marginal discoloration, and secondary caries) were evaluated in a systematic review and meta-analysis. Materials and Methods: A comprehensive search was performed in PubMed, Scopus, Web of Science, LILACS, BBO, and Cochrane. We included only randomized clinical trials. The quality of the evidence for each outcome was assessed using the GRADE tool. Results: A total of 1530 articles were identified, but only 19 reports remained for analysis, all of which were judged to possess “unclear” risk of bias. GIC showed higher retention rates in all follow-ups (1 to 3 years, p < 0.0001; at 5 years, p < 0.00001). No difference was observed for marginal discoloration, marginal adaptation and secondary caries in all follow-ups (p > 0.05). RC showed better color match than GIC only at 2 years (p = 0.03). Higher roughness was observed in GIC in all follow-ups (at 1 year p = 0.0003; at 3 years p = 0.0004). Quality of evidence was graded as moderate or low due to unclear risk of bias and imprecision in some outcomes. Conclusion: The loss of retention of RMGIC/GIC was inferior to that of RC, but a higher roughness was observed in the RMGIC/GIC when compared to RC in all follow-ups of the clinical studies evaluated. In addition, the color match was better with RC only in the 2-year follow-up when compared to GIC. The quality of evidence was judged as moderate to low in these two outcomes. [ABSTRACT FROM AUTHOR]

Purpose: To evaluate the radiopacity, bond strength, and micromorphology of experimental filled dental adhesives. Materials and Methods: Five experimental filled dental adhesives with different concentrations of radiopaque barium-borosilicate glass (wt%) [0 (R0), 30 (R30), 40 (R40), 50 (R50), and 60 (R60)] and the commercial adhesive Adper Single Bond 2 were used in this study. Specimens were prepared by dispensing the uncured resin into a mold (5.0 mm x 1.0 mm). Digital radiographs (n = 5) of both 1-mm-thick adhesive specimens and tooth were taken with a CCD sensor. The gray levels of enamel, dentin, and adhesive systems were measured by histogram analysis and compared. Adhesives were applied to flat dentin surfaces of third molars (n = 7). Resin composite buildups were constructed and sectioned to obtain resin-dentin bonded sticks to test immediately or after 6 months of water storage. Three specimens for each tooth were qualitatively analyzed using scanning electron microscopy. Data on bond strength and radiopacity were evaluated by two-way and one-way ANOVA, respectively, and Tukey's test (α = 0.05). Results: All experimental filled dental adhesives showed radiopacity similar to enamel (p > 0.05) and most yielded significant reductions of bond strength over time. However, the R30 produced a radiopaque material without jeopardizing the bonding of the material to the dentin substrate. Conclusions: The addition of 30% barium-borosilicate oxide produced radiopaque adhesives without jeopardizing the bonding to the dental substrate. [ABSTRACT FROM AUTHOR]

Purpose: To evaluate the fracture resistance (FR) and bond strength (BS) after mechanical fatigue (MF) of flared root canals restored with different restorative techniques for fiber post cementation. Materials and Methods: The root canals of 84 single-rooted premolars were endodontically treated and prepared in order to simulate an oversized root canal, except for the positive control group (PC), in which a pre- fabricated fiber post (PFP) with a diameter compatible with the post cavity was cemented. In the oversized root canals, alternative restorative techniques for post cementation were tested, as follows: NC: negative control (PFP with a diameter smaller than that of the root canal); AP: PFP + accessory posts; RR: root reinforcement with composite resin; DAP: direct anatomical post; IAP: indirect anatomical post. After the luting procedures using Excite DSC and Variolink II, indirect composite crowns were cemented on composite resin cores and the specimens were mechanically fatigued (1.2 x 106 cycles, 40 N). From each group, 8 specimens were subjected to the push-out BS test and the others 6 specimens to the FR test. For both tests, the data were subjected to ANOVA and Scheffe's tests (α = 0.05). Results: In terms of FR, all alternative techniques showed intermediate performance, being similar to both control groups. In terms of BS, only the groups DAP and IAP were similar to the well-adapted condition (positive control group). Conclusion: The use of DAP and IAP should be the first choice for fiber post cementation in oversized root canals. [ABSTRACT FROM AUTHOR]

Purpose: To evaluate the radiopacity, ultimate tensile strength (UTS), microhardness (KHN), degree of conversion (DC), water sorption (WS) and solubility (SL) of experimental adhesives. Materials and Methods: Five experimental adhesives with different concentrations of barium-borosilicate oxide microfillers [0% (R0), 30% (R30), 40% (R40), 50% (R50), 60% (R60)] were formulated based on the adhesive system Ambar (FGM). The adhesive Adper Single Bond 2 (SB, 3M ESPE) was used as commercial reference. For the radiopacity (n = 5), KHN (n = 5), WS (n = 10), and SL (n = 10) tests, adhesive disks were constructed (5.0 mm in diameter and 1.0 mm thick), while for UTS (n = 5), hourglass-shaped specimens with a cross-sectional area of 0.8 mm² were used. The FTIR spectra of unpolymerized and polymerized adhesives were used to determine the DC. Data were submitted to a one-way ANOVA and Tukey's test (α = 0.05). Results: All experimental adhesives showed radiopacity similar to enamel, except those of R0 and SB. Filler addition did not jeopardize the UTS, KHN, or WS of the filled adhesives in comparison with the unfilled version. Except for R40, filler addition reduced the SL. The filled adhesives showed lower DC when compared with R0, but the DC was similar or higher when compared with SB. Conclusions: The addition of barium-borosilicate glass up to 50% did not jeopardize the mechanical properties of the adhesive layer and seems to reduce its solubility. [ABSTRACT FROM AUTHOR]

Purpose: To evaluate the effect of the resin cement thickness (RCT) on bond strength (BS) and gap formation (GF) of fiber posts bonded to root dentin. Materials and Methods: The roots of 24 extracted human mandibular premolars were treated endodontically and the post spaces were prepared using drills with different diameters according to the following groups (n = 8): well adapted (WA), moderately well adapted (MA) and poorly adapted (PA). The fiber glass posts were cemented (Excite DSC and Variolink II) in accordance with the manufacturer's instructions. After 1 week, the roots were transversely sectioned into six 1-mm-thick disks and photographed using an optical microscope to determine the RCT. After this, epoxy resin replicas of each sample were observed using SEM, and the mean length and width of the gaps formed in the cement/dentin/post interface were measured. Finally, each sample was subjected to the push-out test (0.5 mm/min), and the data were statistically analyzed using one-way ANOVA and Tukey's tests at the 5% level of significance. Results: The lowest RCT (µm) was observed for WA and the highest for PA. The group MA showed an intermediate value. Significantly higher push-out BS values were observed for WA compared to the other groups. The MA and PA groups were statistically similar. The highest mean gap length (%) and width (µm) were observed for PA. The groups MA and WA were statistically similar. Conclusion: Lower resin cement thickness resulted in better fiber post adhesion, that is, in higher bond strength and less gap formation. [ABSTRACT FROM AUTHOR]

Purpose: To evaluate the influence of fluoride delivery and restoration time point on the microshear bond strength (mSBS) and degree of conversion (DC) values of an adhesive applied on bleached enamel. Materials and Methods: Fifty-four enamel specimens were submitted to bleaching and divided into 3 groups of n = 18: group HP: 35% hydrogen peroxide (HP); group HPF: HP + 1.23% sodium fluoride application (F); group PF: 38% HP with F. A control group of n = 6 was neither bleached nor fluoridated. Subsequently, each group except the control was subdivided into 3 subgroups (n = 6) to be restored immediately, or at 7 or 14 days. Tygon tubes were filled with composite resin and placed on enamel surfaces, then the mSBS test was performed. The DC of the interface was observed with Raman spectroscopy. The data were submitted to two-way ANOVA and Tukey's and Dunnet's post-hoc test (α = 0.05). Results: The mSBS results showed higher values for groups HP and HPF at 14 days compared with immediate and 7 days (p < 0.05). Lower DC values were obtained in the immediately restored groups HP and HPF, which were significantly different from 7 and 14 days (p < 0.05). mSBS and DC for group PF was similar at all restoration time points and to the control group (p > 0.05). Conclusion: Only the use of a fluoridated in-office bleaching agent (Opalescence Boost PF) proved to be effective for immediately reversing the side effects of low mSBS and DC values when in-office bleaching is used. [ABSTRACT FROM AUTHOR]

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Aim: To evaluate the effect of different in-office bleaching agents on the permeability, roughness and surface microhardness of human enamel. Methods: For evaluation of roughness and microhardness, 40 hemi-faces of 20 premolars were subjected to initial roughness (Ra parameter) and microhardness (VHN) measurements. Thirty-two premolar's crowns were used for permeability test. Then, all specimens were randomly divided into four groups: C - without bleaching (control), HP35 - bleaching with 35% hydrogen peroxide (HP), HPF38 - 38% HP+fluoride, HPC35 - 35% HP+calcium. Final roughness (FR) and microhardness (FM) measurements were evaluated. For permeability, the 32 crowns were immersed in 1% sodium hypochlorite (20 min) and silver nitrate solutions (2 h) and subjected to developing solution under fluorescent light (16 h). Three sections from the crowns were analyzed in light microscope (100x) to evaluate the scores of permeability: Score 0 - no tracer agent penetration; Score 1 - less than half the thickness of enamel penetration; Score 2 - tracer agent reaching half the enamel thickness; Score 3 - entire enamel depth penetration, without reaching dentin and Score 4 - tracer agent reaching dentin. For roughness and microhardness evaluation were used one-way ANOVA and Dunnet post-test for independent samples, and t test for paired samples. For permeability, the data were analyzed by Kruskal Wallis and Dunn tests. Results: A significantly higher permeability and surface roughness were observed in groups HP35, HPF38 and HPC35 compared to the C group, as well as decreased microhardness (p<0.05). Conclusions: All bleaching agents increased permeability and surface roughness, and decreased microhardness of human enamel; thus, the addition of fluoride or calcium was not beneficial. [ABSTRACT FROM AUTHOR]

This study compared the microleakage of class V restorations bonded with various one-step self-etching adhesives. Seventy class V resin- based composite restorations were prepared on the buccal and lingual surfaces of 35 premolars, by using: Clearfil S3 Bond, G-Bond, iBond, One Coat 7.0, OptiBond All-In-One, or Xeno IV. The Adper Single Bond etch-and-rinse two-step adhesive was employed as a control. Specimens were thermocycled for 500 cycles in separate water baths at 5°C and 55°C and loaded under 40 to 70 N for 50,000 cycles. Marginal microleakage was measured based on the penetration of a tracer agent. Although the control showed no microleakage at the enamel margins, there were no differences between groups (p = 0.06). None of the adhesives avoided microleakage at the dentin margins, and they displayed similar performances (p = 0.76). When both margins were compared, iBond® presented higher microleakage (p < 0.05) at the enamel margins (median, 1.00; Q3-Q1, 1.25-0.00) compared to the dentin margins (median, 0.00; Q3-Q1, 0.25-0.00). The study adhesives showed similar abilities to seal the margins of class V restorations, except for iBond®, which presented lower performance at the enamel margin. [ABSTRACT FROM AUTHOR]