Splinting or non-splinting of fixed prostheses on adjacent implants: A critical review.

PURPOSE: The present study aimed to identify, through a critical review of the literature, the success factors associated with the splinting of fixed prostheses on adjacent implants of the posterior sectors in partially edentulous patients compared with those not splinted. STUDY SELECTION: A MEDLINE strategy was implemented based on a research question to systematically search and extract information from databases (PubMed and Scopus) using MeSH terms/keywords identified for each domain. Systematic reviews, clinical and in vitro studies were selected and classified according to eligibility criteria based on the research question and level of evidence using the PRISMA flowchart. RESULTS: A total of 32 studies were selected for data extraction and analysis according to study design (three systematic reviews, 14 clinical studies, and 15 in vitro studies). Overall, the studies found no significant difference in the association between the survival rate and prosthesis type. In clinical studies, there have been no differences in marginal bone loss between splinted and non-splinted prostheses, and the influence of peri-implant status and restorative materials has been poorly evaluated. The distribution of stress and loads determined in the in vitro studies showed results that could favor splinted prostheses; however, are generally associated with implant design. CONCLUSIONS: The need for splinted or non-splinted adjacent implant-supported prostheses remains controversial. The reviewed evidence indicates that factors such as implant size and its relationship with coronal height could be important in decision-making.

The adverse effects of radiotherapy on the structure of dental hard tissues and longevity of dental restoration.

Purpose: The main goal of this study was to evaluate the impact of different ionizing radiation doses on the mineral (carbonate/phosphate ratio, crystallinity index [CI]) and organic (amide III/phosphate, amide I sub-band ratios) structures, as well as the microhardness, of enamel and dentin, along with their influence on the bonding strength stability of the etch-and-rinse (ER) and self-etch (SE) dental adhesive strategies.Materials and methods: Enamel and dentin human tissue specimens were irradiated (with 0, 20, 40, and 70 Gy radiation doses, respectively) and sectioned to perform an attenuated total reflection-Fourier transform IR spectroscopy assay (ATR-FTIR) and the Vickers microhardness (VHN) test to conduct a biochemical and biomechanical evaluation of the tissues. Regarding the adhesive properties, restored enamel and dentin specimens exposed to the same radiation doses were submitted to microshear bond strength (µSBS) tests for enamel in immediate time (IM) and to microtensile bond strength (µTBS) tests after for IM and 12-month (12 M) period of time, Mann-Whitney U tests were implemented, using the ATR-FTIR data for significant differences (α < 0.05), and three- and two-way analyses of variance, along with post-testing, were performed on the µTBS and µSBS data (MPa), respectively (Tukey post hoc test at α = 0.05).Results: The ATR-FTIR results showed a significant decrease (p < .05) in the amide III/phosphate ratio after 20 Gy for the enamel and after 40 Gy for the dentin. The CI was significantly reduced for both tissues after a dose of 70 Gy (p < .05). All radiation doses significantly decreased microhardness values, relative to the respective enamel and dentin controls (p < .05). In both tissues and adhesive strategies, the decrease in bond strength was influenced by ionizing radiation starting from 40 Gy. The ER strategy showed high percentages of enamel cohesive failure. In general, ER in both tissues showed greater and more stable bond strength than SE against increased radiation doses and long term.Conclusions: It is possible to conclude that structural alterations of enamel and dentin are generated by all radiation doses, decreasing the microhardness of dental hard tissues and influencing bond strength over time, starting at 40 Gy radiation dose. The etch-and-rinse strategy demonstrates better adhesive performance but generates cohesive fractures in the enamel.

EDTA Conditioning Increases the Long-term Microtensile Bond Strength to Sclerotic Dentin Mediated by Self-etch Adhesives.

PURPOSE: To evaluate the immediate and 12-month microtensile bond strength (µTBS) of two self-etch adhesives on sclerotic dentin with or without previous EDTA conditioning. The conditioning pattern and the relative area of open dentinal tubules were also evaluated. MATERIALS AND METHODS: Twenty-eight bovine incisors with naturally exposed sclerotic dentin were used. For µTBS testing, 20 teeth were divided into 4 groups (n = 5) according to the combination of the main factors: 1. adhesive (Clearfil SE Bond [CSE, Kuraray] and Adper SE Plus [ADSE, 3M Oral Care]); 2. surface treatment (previous conditioning with EDTA and previous conditioning with distilled water [DW]). The sclerotic surfaces were conditioned with either 17% EDTA or DW for 2 min prior to adhesive application. Composite buildups were constructed. Specimens were sectioned to obtain composite-dentin sticks (0.8 mm2) to be tested immediately or after 12 months (distilled water at 37°C) in tensile mode (0.5 mm/min). The conditioning pattern and the relative area of open dentinal tubules (OT) were evaluated in the remaining eight teeth. After adhesive application, the surfaces were rinsed off with acetone and ethanol. Then the surface was evaluated by SEM with image software. Data from µTBS and OT were submitted to three-way repeated measures ANOVA and data from OT were submitted to one-way repeated measures ANOVA. After, for both tests, Tukey's post-hoc test was applied (α = 0.05). RESULTS: For both adhesives, EDTA resulted in the highest mean immediate µTBS (p = 0.002), which remained stable after 12 months of water storage (p < 0.38). CSE showed higher µTBS when compared to ADSE (p = 0.001). Degradation of the mean µTBS was observed for both adhesives only in the DW groups. Adhesive application plus with EDTA conditioning increased the OT area in comparison with only adhesive application (p < 0.001). CONCLUSION: EDTA conditioning increased the immediate microtensile bond strength in sclerotic dentin substrate and prevented degradation when associated with a self-etch adhesive.

Effect of dentin roughness on the adhesive performance in non-carious cervical lesions: A double-blind randomized clinical trial.

OBJECTIVE: This double-blind randomized clinical trial evaluates the influence of dentin roughening (RO) on the clinical behavior of a new universal multi-mode adhesive (Tetric N-Bond Universal; Ivoclar-Vivadent) applied as self-etch and as etch-and-rinse in non-carious cervical lesions (NCCLs). METHODS: A total of 192 restorations were randomly placed in 48 patients according to the following groups: ER - Etch-and-rinse (no preparation); SE - self-etch (no preparation); ER+RO and; SE+RO. The resin composite Empress Direct (Ivoclar-Vivadent) was placed incrementally. The restorations were evaluated after one week (baseline), 6 and 18 months, using the FDI and USPHS criteria. Statistical analyses were performed using appropriate tests (α=0.05). RESULTS: Fifteen restorations were lost at 18 months (3 for SE, 2 for ER, 5 for SE+RO and 5 for ER+RO) (p >0.05 between groups). Post-operative sensitivity wasn't observed in any of the recall periods. Eighty-four restorations were considered to have minor discrepancies in marginal adaptation at the 18-month recall using the FDI criteria (24 for SE, 18 for ER, 22 for SE+RO and 20 for ER+RO; p >0.05 between groups). Nineteen restorations were considered to have minor discrepancies in marginal discoloration at the 18-month recall (10 for SE, 03 for ER, 05 for SE+RO and 01 for ER+RO; p >0.05 between groups). CONCLUSION: The dentin roughening before application of Tetric N-Bond Universal as self-etch and etch-and-rinse didn't affect the clinical behavior of composite restorations placed in NCCLs.

Comparison of efficacy of tray-delivered carbamide and hydrogen peroxide for at-home bleaching: a systematic review and meta-analysis.

OBJECTIVES: The aim of the study was to compare the color change produced by tray-delivered carbamide peroxide [CP] versus hydrogen peroxide products [HP] for at-home bleaching through a systematic review and meta-analysis. MATERIALS AND METHODS: MEDLINE via PubMeb, Scopus, Web of Science, Latin American and Caribbean Health Sciences Literature database (LILACS), Brazilian Library in Dentistry (BBO), and Cochrane Library and Grey literature were searched without restrictions. The abstracts of the International Association for Dental Research (IADR) and unpublished and ongoing trial registries were also searched. Dissertations and theses were explored using the ProQuest Dissertations and Periodicos Capes Theses databases. We included randomized clinical trials that compared tray-delivered CP versus HP for at-home dental bleaching. The color change in shade guide units (SGU) and ΔE were the primary outcomes, and tooth sensitivity and gingival irritation were the secondary outcomes. The risk of bias tool of the Cochrane Collaboration was used for quality assessment. DATA: After duplicate removal, 1379 articles were identified. However, only eight studies were considered to be at "low" risk of bias in the key domains of the risk bias tool and they were included in the analysis. For ΔE, the standardized mean difference was -0.45 (95 % CI -0.69 to -0.21), which favored tray-delivered CP products (p < 0.001). The color change in ΔSGU (p = 0.70), tooth sensitivity (p = 0.83), and gingival irritation (p = 0.62) were not significantly different between groups. CONCLUSIONS: Tray-delivered CP gels showed a slightly better whitening efficacy than HP-based products in terms of ΔE, but they were similar in terms of ΔSGU. Both whitening systems demonstrated equal level of gingival irritation and tooth sensitivity. CLINICAL SIGNIFICANCE: Tray-delivered CP gels have a slightly better whitening efficacy than HP-based products in terms of ΔE. This should be interpreted with caution as the data of ΔSGU did not show statistical difference between the products.

Degradation of dentin-bonded interfaces treated with collagen cross-linking agents in a cariogenic oral environment: An in situ study.

OBJECTIVES: To evaluate the effect of treatment using collagen cross-linking agents as primer on resin-dentin bond interfaces subjected to cariogenic oral environment (COE). METHODS: Each of forty human teeth had two cavities (4×4×1.5mm) prepared within enamel margins. These cavities were acid-etched and treated by the primers containing one of the following treatment agents (6.5% proanthocyanidins, 0.1% riboflavin-UVA activated light, 5% glutaraldehyde or distilled water as a control group). After that the cavities were bonded and restored with resin composite. One restoration for each tooth was tested immediately (IM) and another was included in an intra-oral palatal device that was placed in each mouth of ten adult volunteers for 14 days in COE. After 14 days, the teeth were removed and each restoration was sectioned to obtain a slice for Knoop microhardness (KHN) and resin-dentin bonded sticks for microtensile bond strength (µTBS) and nanoleakage (NL) evaluation. Data were evaluated by two-way ANOVA and Tukey's tests (α=0.05). RESULTS: After 14days in a COE, the KHN was reduced for all groups, except for the glutaraldehyde group; however, the proanthocyanidins group retained the highest KHN in IM and after COE (p<0.05). The µTBS was not reduced after COE for the proanthocyanidins and glutaraldehyde groups, however only the proanthocyanidins treatment did not increase the NL after COE (p>0.05). CONCLUSION: The in situ study model seems to be a suitable short-term methodology to investigate the degradation of the bonding interfaces under a more realistic condition. Under COE, the proanthocyanidins and glutaraldehyde treatments produced stable interfaces that are worth further clinical investigation.

Collagen cross-linkers on dentin bonding: Stability of the adhesive interfaces, degree of conversion of the adhesive, cytotoxicity and in situ MMP inhibition.

OBJECTIVE: To investigate the effect of collagen cross-links on the stability of adhesive properties, the degree of conversion within the hybrid layer, cytotoxicity and the inhibition potential of the MMPs' activity. METHODS: The dentin surfaces of human molars were acid-etched and treated with primers containing: 6.5wt% proanthocyanidin, UVA-activated 0.1wt% riboflavin, 5wt% glutaraldehyde and distilled water for 60s. Following, dentin was bonded with Adper Single Bond Plus and Tetric N-Bond; and restored with resin composite. The samples were sectioned into resin-dentin "sticks" and tested for microtensile bond strength (µTBS) after immediate (IM) and 18-month (18M) periods. Bonded sticks at each period were used to evaluate nanoleakage and the degree of conversion (DC) under micro-Raman spectroscopy. The enzimatic activity (P1L10 cross-linkers, P1L22 MMPs' activities) in the hybrid layer was evaluated under confocal microscopy. The culture cell (NIH 3T3 fibroblast cell line) and MTT assay were performed to transdentinal cytotoxicity evaluation. Data from all tests were submitted to appropriate statistical analysis (α=0.05). RESULTS: All cross-linking primers reduced the degradation of µTBS compared with the control group after 18M (p>0.05). The DC was not affected (p>0.213). The NL increased after 18M for all experimental groups, except for proanthocyanidin with Single Bond Plus (p>0.05). All of the cross-link agents reduced the MMPs' activity, although this inhibition was more pronounced by PA. The cytotoxicity assay revealed reduced cell viability only for glutaraldehyde (p<0.001). SIGNIFICANCE: Cross-linking primers used in clinically relevant minimized the time degradation of the µTBS without jeopardizing the adhesive polymerization, as well as reduced the collagenolytic activity of MMPs. Glutaraldeyde reduced cell viability significantly and should be avoided for clinical use.

Five-year Effects of Chlorhexidine on the In Vitro Durability of Resin/Dentin Interfaces.

PURPOSE: To evaluate the effect of an acid containing 2% chlorhexidine (Ac/CHX) or a 2% CHX aqueous solution (Aq/CHX) on the immediate and 5-year bonding properties of resin/dentin interfaces produced by two adhesives. The presence of CHX in these interfaces was also evaluated under micro-Raman spectroscopy. MATERIALS AND METHODS: Forty-two molars were ground to expose a flat dentin surface. In the control group, the surfaces were etched with conventional phosphoric acid, and Prime&Bond NT (PB) and Adper Single Bond 2 (SB) were applied. In Ac/CHX, an acid containing 2% CHX was applied after adhesive application. In the Aq/CHX group, an aqueous solution of 2% CHX was applied for 60 s after etching. After placing the restoration, specimens were prepared and tested using the microtensile bond strength test (µTBS, 0.5 mm/min) immediately or after 5 years. For nanoleakage (NL), specimens at each period were immersed in silver nitrate solution and examined by EDX-SEM. In addition, specimens at each period underwent examination for CHX using micro-Raman spectroscopy. Data were submitted to appropriate statistical analysis (a=0.05). RESULTS: After 5 years, NL was more pronounced in the control than in the Ac/CHX or Aq/CHX (p<0.001). Significant reductions in the µTBS were observed for all groups; however, they were more pronounced for the control (p<0.001). CHX was still present in the hybrid layers Ac/CHX or Aq/CHX groups after 5 years. CONCLUSION: The use of a 2% chlorhexidine-containing acid or the application of an aqueous CHX primer may increase the long-term stability of resin/dentin interfaces.

The effect of proanthocyanidin-containing 10% phosphoric acid on bonding properties and MMP inhibition.

OBJECTIVES: This study evaluated the effect of etching using 2% proanthocynidin-containing 10% phosphoric acid 2% PA/10% PhA vs. 35% phosphoric acid 35% PhA on immediate (IM) and 6-months (6M) resin-enamel microshear bond strength (µSBS), resin-dentin microtensile bond strength (µTBS), nanoleakage (NL) and as well as in situ MMP inhibition potential. METHODS: The dentin surface of human were exposed and then etched using 35% phosphoric acid for 15s or 2% PA/10% phosphoric acid for 30s. After rinsing with water, the dentin was bonded with Single Bond Plus (3M ESPE) and composite build-ups were constructed, followed by polymerization. The teeth were sectioned and the bonds were testing for microtensile bond strength (µTBS) and by SEM for NL analysis at IM and 6M. For MMP activity, resin-dentin slices were prepared for in situ zymography, and analyzed under confocal microscopy. For µSBS, others teeth had flattened enamel surfaces etched according the experimental groups and prepared to microshear procedure. The specimens were tested IM and after 6M by microshear bond strength. The data were submitted to two-way repeated measures ANOVA and Tukey's test (α=0.05). RESULTS: Acid-etching using the 2% PA/10% phosphoric acid did not lower the µTBS in IM (p>0.05) compared to the control 35% phosphoric acid group. However, after 6M, only the 2% PA/10% PhA etched dentin had remained stable the resin-dentin bond strength (p<0.05). Bonds made with 35% PhA showed significant increase in NL% after 6M (p<0.05). Dentin bonds made with 2% PA/10% phosphoric acid showed no increase in NL% after 6 months. The MMP activity within the resin-dentin interface was almost completely reduced after 2% PA/10% PhA etching, while the 35% PhA exhibited intense MMP activity. For µSBS, the type of etchant and the storage period did not affect the resin-enamel bond strengths (p>0.05). SIGNIFICANCE: Ten percent phosphoric acid containing 2% PA can produce stable resin-dentin and enamel-resin interfaces, without requiring additional steps in the bonding procedure. Future studies for longer evaluation time are required.

Does the adhesive strategy influence the post-operative sensitivity in adult patients with posterior resin composite restorations?: A systematic review and meta-analysis.

OBJECTIVES: A systematic review and meta-analysis were performed on the risk and intensity of postoperative sensitivity (POS) in posterior resin composite restorations bonded with self-etch (SE) and etch-and-rinse (ER) adhesives. SOURCE: A comprehensive search was performed in the MEDLINE via PubMeb, Scopus, Web of Science, LILACS, BBO and Cochrane Library and SIGLE without restrictions. The abstracts of the annual conference of the IADR (1990-2014), unpublished and ongoing trials registry were also searched. Dissertations and theses were searched using the ProQuest Dissertations and Periodicos Capes Theses databases. STUDY SELECTION: We included randomized clinical trials that compared the clinical effectiveness of SE and ER used for direct resin composite restorations in permanent dentition of adult patients. The risk/intensity of POS was the primary outcome. The risk of bias tool of the Cochrane Collaboration was used. The meta-analysis was performed on the studies considered 'low' risk of bias. DATA: After duplicates removal, 2600 articles were identified but only 29 remained in the qualitative synthesis. Five were considered to be 'high' risk of bias and eleven were considered to be 'unclear' in the key domains, yielding 13 studies for meta-analysis. The overall relative risk of the spontaneous POS was 0.63 (95% CI 0.35 to 1.15), while the stimuli-induced POS was 0.99 (95% CI 0.63 to 1.56). The overall standardized mean difference was 0.08 (95%CI -0.19 to 0.35). No overall effect was revealed in the meta-analyses, meaning that no influence of the ER or SE strategy on POS. SIGNIFICANCE: The type of adhesive strategy (ER or SE) for posterior resin composite restorations does not influence the risk and intensity of POS. CRD42014006617.

Influence of a hydrophobic resin coating on the immediate and 6-month dentin bonding of three universal adhesives.

OBJECTIVE: To test the influence of a hydrophobic resin coating (HC) on the immediate (24h) and 6-month (6m) microtensile dentin bond strengths (µTBS) and nanoleakage (NL) of three universal adhesives applied in self-etch (SE) or in etch-and-rinse (ER) mode. METHODS: Sixty caries-free extracted third molars were assigned to 12 experimental groups resulting from the combination of the factors "adhesive system" (Scotchbond Universal Adhesive [SBU], 3M ESPE; All-Bond Universal [ABU], Bisco Inc.; and G-Bond Plus [GBP], GC Corporation); "adhesive strategy" (SE or ER); "hydrophobic resin coating" [HC] (with or without Heliobond, Ivoclar Vivadent); and "storage time" (24h or 6m). Specimens were prepared for µTBS testing - (24h) half of the beams were immediately tested under tension; and (6m) the other half was stored in distilled water (37°C) for 6m prior to testing. For each tooth, two beams were randomly selected for NL evaluation for both evaluation times. Data were analyzed for each adhesive system using three-way ANOVA and Tukey's post-hoc test (α=0.05). RESULTS: µTBS: (24h): In SE mode, HC resulted in statistically greater mean µTBS for all adhesives. (6m): When HC was not used the mean µTBS for SBU/ER, ABU/ER, GBP/ER and SBU/SE decreased significantly. NL: (24h): SBU/ER, ABU/ER and GBP/SE resulted in a significant reduction in NL when HC was applied. (6m): No significant reduction was observed for SBU/ER or for SBU/SE regardless of the use of HC. SIGNIFICANCE: The application of a hydrophobic resin coating improved the 24h and the 6m performances of all three adhesives systems in SE mode.

A new universal simplified adhesive: 36-Month randomized double-blind clinical trial.

STATEMENT OF THE PROBLEM: It is still debatable which technique should be used with universal adhesives, either etch-and-rinse (wet or dry) or self-etch strategy (with or without selective enamel etching). PURPOSE OF THE STUDY: To evaluate the 36-month clinical performance of Scotchbond Universal Adhesive (SU, 3M ESPE) in non-carious cervical lesions (NCCLs) using two evaluation criteria. METHODS/MATERIALS: Thirty-nine patients participated in this study. Two-hundred restorations were assigned to four groups: ERm: etch-and-rinse+moist dentin; ERd: etch-and-rinse+dry dentin; Set: selective enamel etching; and SE: self-etch. The same composite resin was inserted for all restorations in up to 3 increments. The restorations were evaluated at baseline and at 6-, 18-, and 36-months using both the FDI and the USPHS criteria. Statistical analyses were performed with Friedman repeated measures ANOVA by rank and McNemar test for significance in each pair (α=0.05). RESULTS: Eight restorations (ERm: 1; ERd: 1; Set: 1 and SE: 5) were lost after 36 months, but only significant for SE when compared with baseline (p=0.02 for either criteria). Marginal staining occurred in 6.8% of the restorations (groups ERm, ERd, and Set) and 17.5% of the restorations (group SE), with significant difference for each group when compared with baseline using the FDI criteria (p<0.04), while statistical significance was reached only for SE when compared with baseline using the USPHS criteria (p<0.03). Twenty-eight and 49 restorations were scored as bravo for marginal adaptation using the USPHS and FDI criteria, respectively, with significant difference for each group when compared with baseline (p<0.05). CONCLUSIONS: While there was no statistical difference among bonding strategies when a universal adhesive was used, there were signs of degradation when the universal adhesive was applied in SE mode. The FDI criteria remain more sensitive than the USPHS criteria, especially for the criteria marginal staining and marginal adaptation.

Effect of EDTA conditioning on cervical restorations bonded with a self-etch adhesive: A randomized double-blind clinical trial.

OBJECTIVE: To compare the 18-month retention rates of composite restorations in non-carious cervical lesions [NCCLs] bonded with a self-etch adhesive with and without preliminary conditioning with EDTA. METHODS: Forty-eight patients with two similar-sized NCCL were selected and randomly allocated to one of two groups. Two calibrated operators placed 96 restorations with a one-step self-etch adhesive (Adper Easy One, 3M ESPE). Half of the restorations were placed according to the manufacturer's instructions while, for the other half, the surfaces of the lesions were conditioned with 17% EDTA for 2 min prior to adhesive application. Two blinded and independent examiners evaluated the restorations at baseline, 6, 12, and 18 months, according to the FDI criteria. The comparison between groups in each period was conducted with the Fisher's exact test, and the performance of each group at the different periods was evaluated by McNemar's test (α=0.05). RESULTS: After 18 months, significantly higher retention rates (95% CI) were observed for the EDTA group (95.5 [84.9-98.7]) than the control group (79.6% [65.5-88.9]) (p=0.02). Significant deterioration of the marginal adaptation and marginal discoloration were observed for both groups over the 18-month evaluation. CONCLUSIONS: The preliminary conditioning with EDTA before application of a one-step self-etch adhesive significantly improved the retention rates of composite restorations in cervical lesions. CLINICAL SIGNIFICANCE: Conditioning with EDTA is an alternative that improves the 18-month retention rate of cervical restorations bonded with a self-etch adhesive.

Does active application of universal adhesives to enamel in self-etch mode improve their performance?

OBJECTIVES: To evaluate the effect of adhesion strategy on the enamel microshear bond strengths (µSBS), etching pattern, and in situ degree of conversion (DC) of seven universal adhesives. METHODS: 84 extracted third molars were sectioned in four parts (buccal, lingual, proximal) and divided into 21 groups, according to the combination of the main factors adhesive (AdheSE Universal [ADU], All-Bond Universal [ABU], Clearfil Universal [CFU], Futurabond U [FBU], G-Bond Plus [GBP], Prime&Bond Elect (PBE), and Scotchbond Universal Adhesive [SBU]), and adhesion strategy (etch-and-rinse, active self-etch, and passive self-etch). Specimens were stored in water (37°C/24h) and tested at 1.0mm/min (µSBS). Enamel-resin interfaces were evaluated for DC using micro-Raman spectroscopy. The enamel-etching pattern was evaluated under a field-emission scanning electron microscope (direct and replica techniques). Data were analyzed with two-way ANOVA and Tukey's test (α=0.05). RESULTS: Active self-etch application increased µSBS and DC for five out of the seven universal adhesives when compared to passive application (p<0.001). A deeper enamel-etching pattern was observed for all universal adhesives in the etch-and-rinse strategy. A slight improvement in etching ability was observed in active self-etch application compared to that of passive self-etch application. Replicas of GBP and PBE applied in active self-etch mode displayed morphological features compatible with water droplets. The DC of GBP and PBE were not affected by the application/strategy mode. CONCLUSIONS: In light of the improved performance of universal adhesives when applied actively in SE mode, selective enamel etching with phosphoric acid may not be crucial for their adhesion to enamel. CLINICAL SIGNIFICANCE: The active application of universal adhesives in self-etch mode may be a practical alternative to enamel etching in specific clinical situations.

Effect of enamel bevel on retention of cervical composite resin restorations: A systematic review and meta-analysis.

OBJECTIVES: To identify if enamel bevelling, compared to no treatment, improves the retention rates and marginal discolouration of cervical composite restorations in non-carious cervical lesions (NCCLs) of adult patients, through a systematic review of the literature and meta-analysis. SOURCES: MEDLINE, Scopus, Web of Science, LILACS, BBO Library, Cochrane Library and SIGLE were searched without restrictions, as well as the abstracts of the annual conference of the IADR and the trials registry. Dissertations and theses were searched using the ProQuest Dissertations and Periódicos Capes Theses databases. STUDY SELECTION: We included randomised clinical trials (RCTs) that compared the retention rates restorations in NCCLs placed with or without bevel with at least 1-year follow-up. The risk of bias tool of the Cochrane Collaboration was used for quality assessment. DATA: After duplicate removal, 1356 articles were identified. After abstract screening, 14 studies remained and this number was reduced to four after examination of the full-texts. Only two were considered to have a 'low' risk of bias. The overall risk difference was 0.0 (95% CI -0.04 to 0.04) for the retention rate (p=0.91) and 0.05 (-0.02 to 0.13) for the marginal discolouration (p=0.17). CONCLUSIONS: No superiority of bevelled restorations was observed in the short-term follow-up of 1-year, although this conclusion was based on only two RCTs. There is not enough evidence to support the bevelled technique over non-bevelled for NCCLs over longer periods of time. Better standardization and reporting of RCTs of enamel bevelling are necessary in longer-term follow-ups. CLINICAL SIGNIFICANCE: The literature still lacks a body of evidence to support the benefits of enamel bevel over non-bevelled for longer-term follow-ups, and future randomised clinical trials with low risk of bias should be conducted.

Effects of solvent evaporation time on immediate adhesive properties of universal adhesives to dentin.

OBJECTIVE: To evaluate the microtensile bond strengths (µTBS) and nanoleakage (NL) of three universal or multi-mode adhesives, applied with increasing solvent evaporation times. METHODS: One-hundred and forty caries-free extracted third molars were divided into 20 groups for bond strength testing, according to three factors: (1) Adhesive - All-Bond Universal (ABU, Bisco, Inc.), Prime&Bond Elect (PBE, Dentsply), and Scotchbond Universal Adhesive (SBU, 3M ESPE); (2) Bonding strategy - self-etch (SE) or etch-and-rinse (ER); and (3) Adhesive solvent evaporation time - 5s, 15s, and 25s. Two extra groups were prepared with ABU because the respective manufacturer recommends a solvent evaporation time of 10s. After restorations were constructed, specimens were stored in water (37°C/24h). Resin-dentin beams (0.8mm(2)) were tested at 0.5mm/min (µTBS). For NL, forty extracted molars were randomly assigned to each of the 20 groups. Dentin disks were restored, immersed in ammoniacal silver nitrate, sectioned and processed for evaluation under a FESEM in backscattered mode. Data from µTBS were analyzed using two-way ANOVA (adhesive vs. drying time) for each strategy, and Tukey's test (α=0.05). NL data were computed with non-parametric tests (Kruskal-Wallis and Mann-Whitney tests, α=0.05). RESULTS: Increasing solvent evaporation time from 5s to 25s resulted in statistically higher mean µTBS for all adhesives when used in ER mode. Regarding NL, ER resulted in greater NL than SE for each of the evaporation times regardless of the adhesive used. A solvent evaporation time of 25s resulted in the lowest NL for SBU-ER. SIGNIFICANCE: Residual water and/or solvent may compromise the performance of universal adhesives, which may be improved with extended evaporation times.

Influence of a hydrophobic resin coating on the bonding efficacy of three universal adhesives.

OBJECTIVES: To evaluate the effect of an additional hydrophobic resin coating (HE) on the resin-dentine microtensile bond strengths (µTBS), nanoleakage (NL), and in situ degree of conversion (DC) of three universal adhesives used in the etch-and-rinse (ER) and the self-etch (SE) modes. METHODS: Sixty caries-free extracted third molars were divided into 12 groups according to the combination of the factors adhesive (All-Bond Universal [ABU]; G-Bond Plus [GBP] and Scotchbond Universal [SBU]), adhesive strategy (ER and SE), and the use of HE (Heliobond; yes or no). After restorations were constructed, specimens were stored in water (37°C/24h) and sectioned into resin-dentine beams (0.8mm(2)) to be tested under tension (0.5mm/min). Selected beams from each tooth were used for DC quantification and for NL evaluation. Data from each adhesive were analyzed with two-way ANOVA and Tukey's test (α=0.05). RESULTS: ABU and GBP resulted in higher µTBS in the ER mode. The use of HE increased the µTBS of ABU and GBP only in the SE mode. Lower NL was observed for SBU and ABU in the ER mode+HE, and for GBP in the SE mode+HE. SBU and GBP showed higher DC when used in the ER mode, which was increased with HE application. The DC of ABU was similar in all conditions. CONCLUSIONS: The conversion of 1-step SE to 2-step SE may increase the µTBS and DC of current universal adhesives. The reduction in the NL is more dependent on the adhesive composition than on the bonding strategy.

Prefabricated veneers - bond strengths and ultramorphological analyses.

PURPOSE: To measure the microshear bond strengths (µSBS) of composite resin to the intaglio surface of prefabricated indirect veneers and analyze the FE-SEM ultramorphology of the pretreated intaglio surfaces as well as the fracture modes. MATERIALS AND METHODS: Three veneer systems (veneer and respective luting material) were used in this study: two prefabricated veneer types, Cerinate One-hour (CER, DenMat) and Componeer (CMP, Coltene), and a laboratory- made veneer, IPS e.max Press (IPS, Ivoclar Vivadent) used as the control. For each group, 10 veneers were used. After delimitation of the bonding area with a double-faced adhesive tape, 0.8-mm-diameter cylinders of composite luting material were bonded to the pretreated intaglio surface. After polymerization, the specimens were fractured in shear mode using the wire-loop method in a universal testing machine. The pretreated intaglio surface of two extra veneers and four fractured specimens per group were morphologically characterized using FE-SEM. RESULTS: CER resulted in statistically lower mean µSBS (7.1 ± 1.2 MPa) than the other two veneer systems, CMP (15.2 ± 2.5 MPa) and IPS (14.7 ± 1.7 MPa) at p < 0.0001. As seen with the FE-SEM, the intaglio surface of CMP did not display microretentive features, while multiple microretentions were observed in both CER and IPS after HF etching. CONCLUSION: Within the limitations of this in vitro study, the CMP and IPS veneer systems resulted in greater bond strengths than those of the CER veneer system.

Prolonged exposure times of one-step self-etch adhesives on adhesive properties and durability of dentine bonds.

OBJECTIVES: To evaluate the effect of prolonged exposure times on immediate and 6-month adhesive properties: degree of conversion (DC), nanoleakage (NL) and resin-dentine bond strength (µTBS) of three one-step self-etch adhesive systems (Adper Easy One [EO], Clearfil S(3) Bond [CS3] and Go [GO]). MATERIAL AND METHODS: The adhesives were applied on exposed dentine surfaces of 90 human molars according to manufacturers' instructions and light polymerized for 10, 20, and 40 s at 600 mW/cm(2). Bonded teeth were sectioned to obtain stick-shaped specimens (0.8 mm(2)) and tested under tensile stress (0.5 mm/min) immediately (IM) or after 6 months of water storage. Two bonded sticks from each tooth at each storage time interval were analysed by SEM for NL evaluation. The in situ DC was evaluated by micro-Raman spectroscopy. Data were analysed by appropriate ANOVA and Tukey's test (α = 0.05). RESULTS: Prolonged exposure times significantly increased the DC (%) (10 s [67.4 ± 17.3]; 20 s [85.9 ± 8.9] and 40 s [85.2 ± 9.0]) and decreased the NL (%) (10 s [24.8 ± 13.2]; 20 s [13.3 ± 7.5] and 40 s [13.5 ± 9.3]) for all adhesives; however it did not increase the IM µTBS for two (EO, GO) out of the three adhesives. Furthermore, this technique did not minimize dentine bond degradation. CONCLUSION: Although longer exposure times than those recommended could not prevent degradation of dentine bonds, they could increase DC within the hybrid layer and reduced NL for all adhesives tested.