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The present review is an update of a systematic review that has been published in 2012. Meanwhile, many new clinical trials on resin composites had been published. New materials such as bulk fill resin composites and new glass-ionomer (GIC) based materials had been introduced. The focus of this review was to evaluate the longevity in relation to the material class and adhesive class, while adjusting for a possible study bias effect.The database PUBMED/SCOPUS were searched for clinical trials on posterior resin composites. The inclusion criteria were: (1) studies published between 2000 and 2019, (2) prospective clinical trial with at least 2 years of observation; (2) minimal number of restorations at last recall = 20; (3) report on drop-out rate; (4) report of operative technique and used materials; (5) utilisation of Ryge, modified Ryge or FDI evaluation criteria. The bias of each study was assessed by two independent reviewers using Cochrane Collaboration's tool for assessing risk of bias in randomised trials. For the statistical analysis, linear mixed models fitted on the individual data recorded along time have been used with random effects to account for study, patients and experiment effects. P-values smaller than 0.05 were considered significant.Of the 423 clinical trials, 62 studies (including 110 experiments) met the inclusion criteria. Material class was divided according to the composite filler in microhybrid (39 experiments/2807 restorations), nanohybrid (24 experiments/1254 restorations), and hybrid (22 experiments/1255 restorations). So-called bulk fill materials were treated as a separate category (9 experiments/506 restorations) as were the GIC (11 experiments/2121 restorations) and the compomer materials (5 experiments/238 restorations). Only one study (1.6%) had low risk of bias, 42 (67.7%) were assessed to have unclear risk of bias and 19 (30.6%) had a high risk of bias. In 52.3% of the studies Class II and Class I restorations had been placed. After 10 years, the survival rate for resin composite restorations dropped to about 85-90% with no significant difference between hybrid, microhybrid and nao-hybrid resin materials. The main reasons for restoration replacement were bulk fractures and wear, which accounted for a about 70% of replacements. Caries at the restorative margins accounted for about 20% of the replacements, and retention loss, inacceptable colour match or marginal integrity, endodontic treatment or cusp fracture for about 10% of the replacements of the resin composite restorations. For compomer and GIC restorations the mean overall survival rate was about 80% after 6 years. For GIC, the main reasons for failure were substantial loss of anatomical contour along with loss of proximal contacts and retention loss. Mainly fractures reduced the longevity of compomers restorations. Also, there was no statistically significant difference between hybrid, micro-hybrid, nano-hybrid and bulk fill resin composites with regard to colour match, surface texture, material fractures, and anatomical form.Posterior resin composite restorations that were placed with the enamel etch technique showed the best overall performance; the longevity was not significantly influenced by the filler type or viscosity of resin composite material. With regard to colour match, surface texture and anatomical form, nanohybrid resins were not significantly superior to hybrid or microhybrid resin composites. Compomer and GIC restorations demonstrated considerable shortcomings and had a significant shorter longevity.

Objective. The present study investigated the ability of a chlorhexidine (CHX)-containing primer (0.2% aqueous solution) to inhibit dentinal enzymes, preserve the hybrid layer (HL) and remain within the HL, after 10 years of aging in artificial saliva at 37 degrees C.Methods. Non-carious extracted molars were assigned to two groups, cut into slabs exposing middle/deep dentin, etched and bonded with Adper Scotchbond 1XT (SB1XT) with or without 0.2% CHX aqueous solution pretreatment. Composite build-ups were made, and the specimens were cut in 1-mm thick bonded sticks. In situ zymography was performed on freshly prepared specimens (T-0) and specimens aged for 10 years (T10-yr) at 37 degrees C in artificial saliva, to investigate endogenous gelatinolytic activity within the HL. At T-10-(yr), specimens were also decalcified and embedded in epoxy resin for TEM analysis. Micro-Raman spectroscopy was performed at T-0 and T-10-(yr) to evaluate the chemical profiles in intertubular dentin and the HL.Results. In situ zymography showed less pronounced enzymatic activity in the CHX-pretreated group (p 0.05). TEM results showed that 98% of the HL had been degraded in the control group, while 95% of the HL was intact in the experimental group. Moreover, all the Raman spectra peaks assigned to CHX could be identified only in the CHX-pretreated group (T-0 and T10-yr).Significance. In vitro, CHX remains in the HL after 10 years with its inhibitory effect preserved. This may be the underlying factor for HL preservation after this long aging period.

To measure microshear bond strength (μSBS) and nanoleakage (NL) of self-etch universal adhesives under core buildup restorations using different curing protocols, at 24h and after 6-month water storage.Middle dentin of 55 molars was divided into: Clearfil Universal Bond [CFU], PrimeBond Elect [PBE], and One Coat 7 Universal [OCU]. All-Bond Universal [ABU] and Clearfil SE Bond [CSE] were used as control. CFU, PBE and OCU were: light-cured [LC], dual-cured [DC] and self-cured [SC]. Data were analyzed separately (two-way ANOVA), Tukey's test (α=0.05).μSBS: At 24h OCU/LC resulted in statistically higher μSBS than ABU. CSE/DC showed statistically higher μSBS than all DC adhesives. PBE/LC resulted in significant lower μSBS than the respective DC/SC modes (p0.001). At 6-month, both CFU and PBE (LC/SC), resulted in a significant decrease in μSBS. μSBS for OCU/DC decreased significantly (p0.001) compared to the respective LC/SC modes. NL: At 24h, ABU showed %NL similar to CBU/LC and OCU/LC (p0.05). CSE/DC resulted in significantly higher %NL than OCU/DC but significantly lower than PBE/DC. CFU/LC/SC resulted in significantly lower %NL than CFU/DC. PBE/SC resulted in significant lower %NL than PBE/LC and PBE/DC. OCU/LC and OCU/DC resulted in significant lower %NL than OCU/SC (p0.001). At 6-month ABU, CSE, CFU/LC and CFU/SC, resulted in a significant increase in %NL.Self-cured activator and different curing protocols influenced μSBS and NL of self-etch universal adhesives, but this influence was material-dependent.

Objective To evaluate a range of mechanical parameters of composite resins and compare the data to the frequency of fractures and wear in clinical studies. Methods Based on a search of PubMed and SCOPUS, clinical studies on posterior composite restorations were investigated with regard to bias by two independent reviewers using Cochrane Collaboration’s tool for assessing risk of bias in randomized trials. The target variables were chipping and/or fracture, loss of anatomical form (wear) and a combination of both (summary clinical index). These outcomes were modelled by time and material in a linear mixed effect model including random study and experiment effects. The laboratory data from one test institute were used: flexural strength, flexural modulus, compressive strength, and fracture toughness (all after 24-h storage in distilled water). For some materials flexural strength data after aging in water/saliva/ethanol were available. Besides calculating correlations between clinical and laboratory outcomes, we explored whether a model including a laboratory predictor dichotomized at a cut-off value better predicted a clinical outcome than a linear model. Results A total of 74 clinical experiments from 45 studies were included involving 31 materials for which laboratory data were also available. A weak positive correlation between fracture toughness and clinical fractures was found (Spearman rho = 0.34, p = 0.11) in addition to a moderate and statistically significant correlation between flexural strength and clinical wear (Spearman rho = 0.46, p = 0.01). When excluding those studies with “high” risk of bias (n = 18), the correlations were generally weaker with no statistically significant correlation. For aging in ethanol, a very strong correlation was found between flexural strength decrease and clinical index, but this finding was based on only 7 materials (Spearman rho = 0.96, p = 0.0001). Prediction was not consistently improved with cutoff values. Significance Correlations between clinical and laboratory outcomes were moderately positive with few significant results, fracture toughness being correlated with clinical fractures and flexural strength with clinical wear. Whether artificial aging enhances the prognostic value needs further investigations.

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.

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.

To examine the effects of the combined use of chlorhexidine and ethanol on the durability of resin-dentin bonds.Forty-eight flat dentin surfaces were etched (32% phosphoric acid), rinsed (15 s) and kept wet until bonding procedures. Dentin surfaces were blot-dried with absorbent paper and re-wetted with water (water, control), 1% chlorhexidine diacetate in water (CHD/water), 100% ethanol (ethanol), or 1% chlorhexidine diacetate in ethanol (CHD/ethanol) solutions for 30 s. They were then bonded with All Bond 3 (AB3, Bisco) or Excite (EX, Ivoclar-Vivadent) using a smooth, continuous rubbing application (10 s), followed by 15 s gentle air stream to evaporate solvents. The adhesives were light-cured (20 s) and resin composite build-ups constructed for the microtensile method. Bonded beams were obtained and tested after 24-h, 6-months and 15-months of water storage at 37°C. Storage water was changed every month. Effects of treatment and testing periods were analyzed (ANOVA, Holm-Sidak, p0.05) for each adhesive.There were no interactions between factors for both etch-and-rinse adhesives. AB3 was significantly affected only by storage (p=0.003). Excite was significantly affected only by treatments (p=0.048). AB3 treated either with ethanol or CHD/ethanol resulted in reduced bond strengths after 15 months. The use of CHD/ethanol resulted in higher bond strengths values for Excite.Combined use of ethanol/1% chlorhexidine diacetate did not stabilize bond strengths after 15 months.

To evaluate the effects of chlorhexidine (CHX) addition in different concentrations into simplified etch-and-rinse adhesives on the ultimate tensile strength (UTS), water sorption (WS), solubility (SO) and the rate of CHX release over time.We added CHX diacetate to Ambar [AM] (FGM) and XP Bond [XP] (Dentsply) in concentrations of 0, 0.01, 0.05, 0.1 and 0.2 wt%. For UTS (n=10 for each group), adhesive specimens were constructed in an hourglass shape metallic matrix with cross-sectional area of 0.8 mm(2). Half of specimens were tested after 24 h and the other half after 28 days of water storage in tension of 0.5 mm/min. For WS and SO (n=10 for each group), adhesive discs (5.8 mm×1.0 mm) were prepared into a mold. After desiccation, we weighed and stored the cured adhesive specimens in distilled water for evaluation of the WS, SO and the cumulative release of CHX over a 28-day period. For CHX release (n=10 for each group), spectrophotometric measurements of storage solution were performed to examine the release kinetics of CHX. We subjected data from each test to ANOVA and Tukey' test (α=0.05).XP Bond adhesive showed significantly more WS and SO and lower UTS than Ambar. In general, the addition of CHX did not alter WS, SO and UTS of the adhesives. XP showed a higher CHX release than AM (p0.05) in all concentrations and the final amount of CHX release was directly proportional to the initial CHX concentration added to the adhesives. After 28 days of water storage, approximately 20% of CHX was released from XP and 8.0-12.0% from AM.Addition of CHX to commercial adhesive is a feasible method to provide a controlled release of CHX over time without jeopardizing WS, SO and UTS of the adhesives.Manufacturers should consider adding CHX to commercial adhesives to provide a controlled release of CHX over time.

To examine the effect of prolonged application time on the early and 3-year resin-dentin microtensile bond strength.Water/ethanol (Single Bond [SB]) and acetone-based systems (One Step [OS]) were employed. A flat superficial dentin surface was exposed in third human molars by wet abrasion. The adhesives were applied to a delimited area of 52 mm2 on wet surfaces, for 40, 90, 150 and 300 s. Four teeth were assigned for each experimental condition. Composite build-ups were constructed incrementally. After water storage at 37 degrees C for 24 h, teeth were sectioned to obtain sticks with cross-sectional areas of 0.8 mm2 to be tested in tension (0.5 mm/min) either immediately (IM) or after 3 years (3Y) of water storage. The microtensile bond strength (microTBS) values were analyzed by two way repeated measures ANOVA and Tukey's test (alpha=0.05).The 90- and 150-s groups achieved the highest IM microTBS for OS (p0.01). For SB, the highest IM microTBS values were observed after 300-s application (p0.01). Significant decreases in microTBS were observed for OS in the 40- and 90-s groups after 3Y, except for the 150-s group. With regard to SB, after 3Y significant drops in microTBS values were observed for the 40- and 150-s groups, except for the 300-s group.Prolonged application times can increase the immediate microTBS of two-step etch-and-rinse adhesive systems and make the adhesive layer more stable over time.

To compare the effects of moisture and rubbing action on the microtensile bond strength (BS) of an ethanol/water-based (Single Bond [SB]) and an acetone-based system (One-Step [OS]) to dentin.On 60 human molars, a flat superficial dentin surface was exposed by wet abrasion. Two coats of the adhesives were applied on either a dry (D) or rewetted surface (W), under no rubbing action (NRA), slight (SRA) or vigorous rubbing action (VRA). After light curing (600 mW/cm2/10 s), composite build-ups were constructed incrementally and specimens were stored in water (37 degrees C/24 h). They were longitudinally sectioned in the "x" and "y" directions to obtain bonded sticks (0.8 mm2) to be tested in tension at 0.5 mm/min. Resultant BS was expressed as an index that includes bond strength values of the different fracture patterns and the specimens that failed during preparation for testing. The data were analyzed by a three-way ANOVA and Tukey's multiple comparison tests (95%).The interactions moisture/agitation and adhesive/agitation were statistically significant (p0.05). In D groups, the highest BS was obtained under VRA (37.11 +/- 7.3). In W groups, the BS at SRA (41.82 +/- 8.4) and VRA (38.89 +/- 8.2) were similar. For SB system, the SRA (33.6 +/- 8.3) and VRA groups (41.26 +/- 5.9) yielded similar BS while for OS the VRA was essential to reach high BS (34.2 +/- 8.4).High BS to dentin can be obtained, under dry conditions, when ethanol/water and acetone-based systems, are vigorously agitated in the surface. On wet dentin, slight agitation seems to be enough to provide high BS to dentin.

Summary Objectives The objective was to evaluate the response of human pulps capped with different components from a total-etch three-step adhesive system. Methods Direct pulp capping was performed in 25 caries-free human premolars scheduled for extraction due to orthodontic treatment. The teeth were randomly divided in five groups, and capped with the following materials: Group 1—acid+primer+adhesive were used as recommended; Group 2—only primer was applied; Group 3—only bonding resin (light-cured for 10 s); Group 4—only composite resin (light-cured for 40 s); Group 5—calcium hydroxide. After capping, all teeth were restored with ScotchBond Multi Purpose Plus and Z-100 was placed incrementally. After 60 days, the teeth were extracted and processed for light microscopic examination (H/E) according to a histological score system. These were subjected to non-parametric tests ( α Results Overall, the histological features showed that groups 1–4 were quite similar and inferior to group 5. In groups 1–4 the pulp response varied from acute inflammatory cell infiltrate with varying degrees to necrosis. The groups 3 and 4 showed a trend towards better pulp response, since a normal connective tissue could be observed in more than half of the sample. All teeth from group 5 showed normal connective tissue below an amorphous dentin bridge. Significance Adhesive components (primer or adhesive) as well as a composite should be avoided for pulp capping. Ca(OH) 2 should be the first choice for pulp capping.

To analyze the effects of different surface moisture on bond strength (BS) durability of an ethanol/water based, Single Bond (SB); an acetone-based, One-Step (OS); and a water-based, Syntac Single Component (SC) adhesive system to dentin.Forty-five human third molars had their superficial dentin surface exposed flat by abrasion. The adhesives were applied to a delimited area of 52 mm(2) on either air-dried (30 s) or rewetted surfaces (2.5 or 4.0 microl) followed by resin composite build-ups. After storage in water at 37 degrees C (24 h), the teeth were sectioned to obtain bonded sticks with a cross-sectional area of 0.8 mm(2). The sticks, from each tooth, were divided, stored in water at 37 degrees C and tested either immediately or after 6 months (6 M) at 0.5 mm/min. BS was expressed as an index that considers cohesive failures and estimated values of premature debonded specimens.Three-way ANOVA showed statistically significant effects for moisture degree, storage time and double interactions (p0.05). While SB and SC achieved higher BS at 0 and 2.5 microl of water, for OS the BS was higher at 4.0 microl of water. Regardless of the moisture degrees, reductions in BS were observed after 6 M storage for SB and OS (p0.05), but not for SC (p0.05). No difference in BS between the 24 h and 6 M storage was found when the moisture was set at the extreme conditions. Significant reduction in BS was observed when the moisture was set at 2.5 microl.The bond strength of different solvent-based adhesive systems gradually decreases over time, regardless of the variable moisture pattern used for the bonding procedure.

To evaluate the linear polymerization shrinkage (LPS) and its effect upon mean gap width, bond strength and cohesive strength of a composite placed under different constraints (C-factors--CF) and filling techniques.Composite was placed in cavities sized 4 x 4 x 2 mm3 (CF = 3) or on flat dentin surfaces (CF = 0.3) of bovine incisors, after adhesive application. They were inserted in one or three increments, and light cured (600 mW/cm2) for 80 s. The LPS was measured by placing a probe on the top surface of the composite in order to measure its dislodgment in the top-bottom direction. Half of the sample was sectioned to obtain composite resin sticks subjecting them to tensile forces at 0.5 mm/min. The other half of the sample was sectioned and the mean gap width was measured in both sides of the sections. Then the sections were sliced again to obtain composite/dentin sticks. The mean gap width in the sticks was performed before subjecting them to tensile forces at 0.5 mm/min. Data was analyzed by a two-way ANOVA and the correlation between the bond strength and gap width was analyzed by simple linear regression.(1) Linear polymerization shrinkage: significant differences were observed for the interaction (p0.05). Under the low constraint, the LPS were similar for both filling techniques. Under higher constraint, polymerization shrinkage was lower for the incremental technique. (2) Gap width and bond strength: no difference was detected either for interaction, or for technique (p0.05). Under higher constraint, the gap width was higher and the bond strength lower. (3) The cohesive strength of composite resin was similar for all groups (p0.05). No correlation between bond strength and gap width was found (p = 0.17).The effects of polymerization shrinkage were not reduced by the filling technique under the different cavity constraints tested.