Search Results (58)

The objective of this study was to evaluate the effect of morpholine on saliva-contaminated resin-based composite (RBC)-CAD/CAM material repaired with resin composite. Fifty RBC-CAD/CAM materials were fabricated and assigned to five groups and surface-treated with saliva, phosphoric acid (PHR), morpholine (MRL), and a universal adhesive agent (Scotchbond universal plus, SCP) based on the following techniques: group 1, saliva; group 2, SCP; group 3, saliva + SCP; group 4, saliva + PHR + SCP; and group 5, saliva + MRL + SCP. An ultradent model was placed on the specimen center, and then the resin composite was pressed and light-cured for 20 s. A mechanical testing device was used to evaluate the samples’ shear bond strength (SBS) scores. The debonded specimen areas were inspected under a stereomicroscope to identify the failure mechanisms. The data were analyzed using one-way ANOVA, and the significance level (p < 0.05) was set with Tukey’s test. The highest SBS values were in groups 2, 4 and 5, with values of 21.43 ± 1.93, 20.93 ± 1.46, and 22.02 ± 1.77 MPa, respectively. However, they were not statistically different (p > 0.05). Group 1 had the lowest SBS value by a significant amount (1.88 ± 1.01 MPa). All specimens in group 1 showed adhesive failures. Moreover, groups 2–5 found cohesive and mixed failures. In conclusion, morpholine and phosphoric acid effectively enhance bond strength. These results indicate that alternative surface modifications with morpholine for saliva-contaminated RBC-CAD/CAM materials can significantly improve the outcome. Full article

This study aimed to investigate the impact of varying concentrations of graphene oxide (GO) combined with two surface coating agents (SCAs) and two dental adhesives (DAHs) used as SCAs on microhardness. Two SCAs, Resin Glaze (ReG) and Coat-It (CoI) (Shofu Inc., Kyoto, Japan), along with two DAHs, Adper^TM Scotchbond^TM Multi-purpose Adhesive (AdA) (3M ESPE, Seefeld, Germany) and OptiBond^TM FL Adhesive (OpA) (Kuraray Noritake Dental Inc., Okayama, Japan), were tested. The ten concentrations of GO—0 wt % (control), 0.05 wt %, 0.1 wt %, 0.3 wt %, 0.5 wt %, 0.7 wt %, 1 wt %, 2 wt %, 5 wt %, and 10 wt %—were incorporated into the SCAs and DAHs to create the experimental formulations. These mixtures underwent centrifugation for homogenization, followed by sonication for dispersion. The mixture was poured into the 3D-printed resin mold (10 mm in diameter and 1 mm in height) and then cured with a light curing unit for 180 s. The cured specimens were then kept in distilled water at 37 ± 1 °C for 24 h. All specimens were then subjected to evaluation of their microhardness properties using a Knoop hardness testing machine. Data were collected, and the statistical analysis was conducted using Two-way ANOVA followed by Tukey’s post-hoc tests at a 0.05 level of significance. According to the results, surface hardness was significantly increased (p < 0.05) when 0.3–0.7 wt % of GO was added to ReG, CoI, and AdA, compared to the control group. However, surface hardness was significantly increased (p < 0.05) when 0.05–0.3 wt % of GO was added to OpA compared to the control group. In the control groups, the microhardness of OpA was significantly higher than that of the other groups (p < 0.05). In the 0.1 wt % groups, the microhardness of OpA was significantly higher than that of the other groups (p < 0.05). At 0.5 wt %, ReG, CoI, and AdA showed significantly higher microhardness compared to their respective control groups (p < 0.05). In the 1–10 wt % groups, the microhardness of ReG, CoI, and AdA demonstrated a gradual, significant decrease compared to the 0.7 wt % groups. Whereas in the 0.5–10 wt % groups, the microhardness of OpA showed a significant gradual decrease compared to the 0.3 wt % group. In summary, the optimal GO concentration could improve the surface hardness of ReG, CoI, AdA, and OpA. Full article

Background: This study aimed to analyze and compare the translucency and marginal adaptation of five resin-based materials used as occlusal sealants, both before and after simultaneous fatigue and thermocycling. Two null hypotheses were tested: (1) All tested materials allow the transillumination of sealed occlusal carious lesions. (2) There are no differences in marginal adaptation before and after simultaneous fatigue and thermocycling. Methods: Forty extracted human molars with early occlusal caries lesions were randomly divided into five equal groups. Near-infrared transillumination images of cleaned occlusal surfaces were captured before and after applying the following sealants: (I) OptiBond FL (adhesive alone), (II) OptiBond FL (primer and adhesive) (Kerr Corp., Brea, CA, USA), (III) Scotchbond Universal (3M, St. Paul, MN, USA) combined with OptiBond FL adhesive, (IV) Fissurit (VOCO GmbH, Cuxhaven, Germany), (V) Helioseal Clear (Ivoclar Vivadent AG, Schaan, Liechtenstein). A scanning electron microscope was used to assess marginal adaptation before and after simultaneous fatigue and thermocycling. The percentages of continuous margins (CMs) were quantified before and after the fatigue test and statistically compared (Shapiro–Wilk Normality test, two-way ANOVA with Fisher’s post hoc test). Results: Helioseal Clear and Fissurit were fully transparent under near-infrared transillumination. The percentage of closed margins significantly decreased after loading in one group: OptiBond FL primer application before adhesive application significantly reduced marginal adaptation. Conclusion: OptiBond FL (adhesive), Scotchbond Universal with OptiBond FL (adhesive), Fissurit, and Helioseal Clear provided excellent marginal adaptation. However, using OptiBond FL primer on enamel negatively impacted adaptation. Helioseal Clear and Fissurit, as transparent sealants, may allow lesion monitoring using an 850 nm transillumination camera. Full article

This study investigated the effects of acid etching with grape seed extract (GSE)-modified etchants, varying phosphoric acid (PA) concentrations, on endogenous collagenolytic activity of etched dentin, adhesive–dentin (A/D) interfacial formation, and bond strength over time. Three PA concentrations (5%, 10%, and 20%) were combined with 2% GSE (5PA/GSE, 10PA/GSE, and 20PA/GSE) and compared to a control (CT) group using 32% PA gel (3M Universal Scotchbond etchant). Seventy-four caries-free human third molars were sectioned to expose dentin surfaces, which were etched and analyzed. In situ zymography with confocal laser microscopy was used to assess endogenous collagenolytic activity in etched dentin specimens. For A/D interfacial morphology and bond strength, etched dentin was bonded with Adper Single Bond Plus adhesive (3M ESPE) and composite buildup. The interfacial morphology of A/D specimens was evaluated using either Goldner’s trichrome staining under light microscopy after microtomy sectioning or scanning electron microscopy. A/D specimens were stored in either TESCA buffer or collagenase solution and tested immediately (IM) or at multiple time points over one year using the microtensile bond strength (μTBS) test. Data were analyzed by one- or three-way ANOVA followed by Games–Howell or Tukey’s tests (α = 0.05). GSE-modified etchants significantly reduced endogenous collagenolytic activity (p < 0.05). Although GSE-modified etchants resulted in thinner A/D interfaces, the bond strength remained unaffected (p > 0.05). Bond strength stability was prolonged up to one year with 5PA/GSE and 10PA/GSE (p < 0.001), while CT or 20PA/GSE showed significant degradation by 17 weeks (p < 0.01). Storage in the more aggressive collagenase solution did not further reduce the bond strength compared to TESCA buffer (p = 0.966). Acid etching with GSE-modified etchants effectively inhibits endogenous MMP-mediated collagenolytic activity. At 5% and 10% PA, this approach enhances the stability of the A/D bond strength, offering a promising modification for dentin bonding protocols. Full article

The number of resin cements marketed for fiber post cementation has increased significantly. This study compared the push-out bond strength (PBS) of self-adhesive and universal resin cements used to lute fiber posts at 24 h and after 6 months of aging in artificial saliva. Fiber posts were luted to eighty human roots endodontically treated with four self-adhesive/one-step resin cements, with one of them also used in combination with its appropriate tooth primer; one universal resin cement, applied as one-step or together with its corresponding universal adhesive (multi-step); and one adhesive/multi-step resin cement, as a control. After storage (24 h or 6 months), the interfaces were subjected to PBS tests and the data were analyzed by two-way ANOVA and Tukey and Student’s t-tests (p < 0.05 defined as statistical significance). The results showed that Scotchbond Universal Plus + RelyX Universal attained statistically higher values at 24 h and 6 months. At 24 h, all resin cements yielded similar PBS to root dentin, while at 6 months, NormoCem obtained the lowest PBS. Storage for 6 months significantly decreased PBS for NormoCem and Multilink Automix. Root section did not influence PBS regardless of storage time. It was concluded that PBS is resin cement dependent. The universal resin cement, RelyX Universal, applied in combination with Scotchbond Universal Plus adhesive, obtained a higher and more stable PBS than the other resin cements tested. Full article

Matrix metalloproteinase (MMP)-induced collagen degradation at the resin-dentin interface remains a significant challenge for maintaining the longevity of dental restorations. This study investigated the effects of epigallocatechin-3-gallate (EGCG), a potent MMP inhibitor, on dental adhesive curing efficiency when encapsulated in halloysite nanotubes (HNTs). EGCG-loaded HNTs were incorporated into a commercial dental adhesive (Adper Scotchbond Multi-Purpose) at 7.5% and 15% w/v concentrations. To isolate the effects of each component, the study included three control groups: unmodified adhesive (negative control), adhesive containing only HNTs, and adhesive containing only EGCG (0.16% and 0.32%, equivalent to the EGCG content in EGCG–HNT groups). Degree of conversion (DC), polymerization conversion (PC), and Vickers micro-hardness (VHN) were assessed to evaluate curing efficiency. The addition of 7.5% EGCG-encapsulated HNTs maintained curing properties similar to the control, showing no significant differences in DC (80.97% vs. 81.15%), PC (86.59% vs. 85.81%), and VHN (23.55 vs. 24.12) (p > 0.05). In contrast, direct incorporation of EGCG at 0.32% significantly decreased DC (73.59%), PC (80.63%), and VHN (20.56) values compared to both control and EGCG–HNT groups (p < 0.05). Notably, HNT encapsulation mitigated these negative effects on polymerization, even at higher EGCG concentrations. These findings demonstrate that EGCG encapsulation in HNTs can maintain the curing efficiency of dental adhesives while potentially preserving the MMP-inhibitory benefits of EGCG. Full article

This study investigated the effects of different surface treatments and a silane-containing adhesive on the repair bond strength between fresh and aged resin composites. A total of 140 composite specimens were prepared and aged for 24 h or 4 months. Each group was subdivided into seven subgroups (n = 10) depending on the surface treatment (no surface treatment (NT), sandblasting (SAND), or Sof-lex coarse disc (DISC)) in combination with the use of the silane-containing adhesive ScotchBond Universal Plus (SBU) or an adhesive without silane Prime&Bond Universal (P&B). The same composite was used for the repair as for the primary specimen. Specimens were dark stored in distilled water at 37 °C for 28 days. Shear bond strength was tested at a crosshead speed of 0.5 mm/min. The Kruskal–Wallis test with Bonferroni’s post-hoc adjustment (α = 0.05) and the Mann–Whitney U-test were used for the statistical analysis. The results are shown as the median with the interquartile range. The highest bond strength (MPa) was achieved after 24 h in the DISC+P&B (20.39(16.85–28.83)). In the fresh 24 h group, the SAND+P&B (12.25(8.28–15.05)) and DISC+SBU (18.37(15.16–21.29)) were statistically similar. In the 4-month groups, both adhesives and surface treatments performed similarly. The NT, SAND, and DISC groups without adhesives had the lowest bond strength. In the repair of fresh or aged composite, the silane-containing adhesive SBU was not superior to the adhesive without the silane (P&B). Full article

The objectives of this study were to evaluate the bonding durability of four different self-etch adhesives to dentin after 24 h and thermal cycling (TC) and to measure the degree of polymerization conversion (DC) in situ. Two-step self-etch adhesives, Clearfil SE Bond 2 (SE2, Kuraray Noritake Dental) and G2-Bond Universal (G2B, GC), and one-step self-etch adhesives, Scotchbond™ Universal Plus Adhesive (SBU, 3M ESPE) and Clearfil Universal Bond Quick (UBQ, Kuraray Noritake Dental), were used. The labial surfaces of bovine teeth were ground to create flat dentin surfaces. The adhesives were applied according to the manufacturers’ instructions. After resin composite buildup and 24 h water storage, the specimens were sectioned into beams and all groups were subjected to thermal stress for 0, 10,000 (10k), or 20,000 (20k) cycles followed by micro-tensile bond strength (µTBS) testing. In situ DC was investigated with a laser Raman microscope. The µTBS data were statistically analyzed and subjected to a Weibull analysis. The different groups were compared at the characteristic strength (63.2% probability of failure) (α = 0.05). Two-Way ANOVA was used to show the effect of different adhesives and thermal cycling on the mean DC% followed by Tukey’s multiple comparison post hoc test. G2B/TC10k resulted in a significant increase in the µTBS compared to TC0. SBU/TC20k showed significantly higher µTBS compared to TC0. For comparison between different tested adhesives, SBU showed a significantly lower µTBS compared to G2B after TC10k. G2B and SBU showed a greater number of adhesive failures after TC. Mean DC% was different for each adhesive. The newly developed MDP- and HEMA-free 2-SEA showed similar bonding performance with the gold-standard 2-SEA. However, there is still room for further improvement in terms of SEAs. Full article

Ionizing radiation in therapeutic doses alters the composition and properties of dentin and resin composites. This may influence the adhesion of restorative materials to irradiated dentin and compromise the success of the restorative treatment. The objective of this study was to evaluate the effect of ionizing radiation on the shear bond strength (SBS) of bulk-fill composite materials to dentin. Coronal dentin slabs (N = 90) were embedded in acrylate and randomly assigned to six groups (N = 15) depending on the time of radiation (70 Gy) and material (SDR Plus Bulk Fill Flowable and Tetric EvoFlow Bulk Fill (TET)): (1) control group (CG) SDR; (2) CG TET; (3) radiation + SDR; (4) radiation + TET; (5) SDR + radiation; and (6) TET + radiation. Composite cylinders were bonded to the dentin slabs using Scotchbond Universal Plus Adhesive. The specimens were stored in distilled water and fractured in shear mode after 7 weeks. Radiation before and after restoration resulted in an SBS decrease. The SBS was statistically significantly lower in groups 5 and 6 (p < 0.05). The difference between the bulk-fill composites was not significant (p > 0.05). In the CGs, adhesive fractures prevailed. In groups 3 and 4, cohesive fractures in the dentin were more frequent, and in groups 5 and 6, cohesive fractures in the material. Radiotherapy affects the SBS of bulk-fill composites to dentin. Immediate radiation after restoration resulted in the lowest SBS in both bulk-fill composite materials. Full article

This study investigated the effect of 3 s light-curing with a high-power LED curing unit on the shear bond strength of bulk-fill composites. Four bulk-fill composites were bonded to dentin with a universal adhesive (Scotchbond Universal Plus): two materials designed for rapid curing (Tetric PowerFill and Tetric PowerFlow) and two controls (Filtek One Bulk Fill Restorative and SDR Plus Bulk Fill Flowable). The 4 mm composite layer was light-cured with Bluephase PowerCure for 20 s at 1000 mW/cm² (“20 s”) or for 3 s at 3000 mW/cm² (“3 s”). The samples were stored at 37 °C in distilled water and tested after 1, 6 and 12 months. The samples polymerised in the “3 s” mode had statistically similar or higher bond strength than the samples cured in “20 s” mode, except for the Tetric PowerFlow (1 month) and SDR+ (6 month). The flowable materials Tetric PowerFlow and SDR Plus initially showed the highest values in the “3 s” and “20 s” groups, which decreased after 12 months. The bond strength was statistically similar for all materials and curing protocols after 12 months, except for Tetric PowerFill cured with the “3 s” protocol (21.22 ± 5.0 MPa), which showed the highest value. Tetric PowerFill showed the highest long-term bond strength. While “3 s” curing resulted in equal or better shear bond strength, its use can only be recommended for a material with an AFCT agent such as Tetric PowerFill. Full article

This study evaluated the effect of simulated pulpal pressure (SPP) conditions and storage time on contemporary adhesive systems’ microtensile bond strength (µTBS) to dentin. Extracted human molars were prepared and randomly divided into four groups according to the adhesives: Clearfil Megabond 2 (CSE), Beautibond Xtreme Universal (BXU), G2-Bond (G2B), and Scotchbond Universal Plus (SBP). Each adhesive group was further divided following the SPP conditions: control with no simulation (SPP-CTR), SPP with distilled water (SPP-DTW), and SPP with fetal bovine serum (SPP-FBS). Resin composite build-ups were prepared, and teeth were stored in water (37 °C) for 24 h (24 h) and 3 months (3 m). Then, teeth were sectioned to obtain resin–dentin bonded beams and tested to determine the µTBS. Data were analyzed using three-way ANOVA, Tukey post hoc tests (=0.05), and Weibull failure analysis. Failure mode was observed using scanning electron microscopy. The µTBS response was affected by adhesive systems, simulated pulpal pressure conditions, and storage time. SPP-CTR groups presented a higher overall bond strength than SPP-DTW and SPP-FBS, which were not significantly different from each other. Only for SBP, the SPP-FBS group showed higher µTBS than the SPP-DTW group. The Weibull analysis showed that the bonding reliability and durability under SPP-DTW and SPP-FBS were inferior to SPP-CTR, and the 24 h bonding quality of adhesives to dentin was superior to that of 3 m. SPP drastically reduced the µTBS of all adhesives to dentin regardless of solution (distilled water or fetal bovine serum). Storage after 3 m also decreased µTBS despite the SPP condition. Full article

Introduction: The aim of this in vitro study was to compare the quality of marginal sealing at the cervical margins of indirect and direct composite resin restorations in mesio-occluso-distal (MOD) cavities. Material and method: MOD preparations were performed on 30 extracted teeth. The mesial cervical margin of each tooth was relocated using a flow composite resin (Enamel Plus HRi Flow, Micerium, Avegno, GE, Italy), then the samples were divided into three groups. In group A, the cavities were directly restored using a nanohybrid composite resin (Miris 2 Coltène Whaledent, Altstaetten, Switzerland) and a universal adhesive (ScotchBond Universal, 3M ESPE, St. Paul, MN, USA) by the etch-and-rinse strategy, for group B, the restoration procedure was similar but the self-etch strategy was used, and the samples in group C were filled using the inlay technique. Each sample was stored for 48 h in a 2% methylene blue solution, then it was cut in a mesio-distal direction using a Struers Secotom 50 device (Cleveland, OH, USA). The marginal sealing and adhesive interface were assessed for each sample at the cervical margin by optical microscopy (OM) and scanning electron microscopy (SEM). One-way ANOVA and Bonferroni post-hoc tests were used with a significance level of 0.05. Results: Significant differences were recorded within groups A and C, between mesial and distal margins (p = 0.02 in group A and p = 0.043 in group C). Conclusions: The marginal sealing is more effective in MOD inlay restoration compared to direct restorations. Relocation of the cervical margin with flow composite resin and the use of different adhesive strategies do not improve the marginal sealing. Full article

This study analyzed the dentin shear bond strength (SBS) of an etch-and-rinse (ER) or a self-etch (SE) adhesive incorporated with multifunctional polyhedral oligomeric silsesquioxanes (MA-POSS-8). An ER adhesive (Solobond Plus, VOCO GmbH, Cuxhaven, Germany) and a universal adhesive applied in SE mode (Scotchbond Universal, 3M, St. Paul, MN, USA) were infiltrated with MA-POSS-8 (Hybrid Plastics Inc., Hattiesburg, MS, USA) at 5 wt.% or 10 wt.%. Pure adhesives served as controls. Bovine dentin specimens were conditioned with one of the adhesives prior to the application of a nano-hybrid composite (Venus Diamond A3, Kulzer, Hanau, Germany). SBS and failure modes were determined after water storage for 24 h, 6 months, 12 months, or 24 months (each subgroup n = 20). Statistical analysis was performed using ANOVAs, Weibull statistics, and χ² tests (p < 0.05). SBSs for the control groups after 24 h were 17.4 ± 4.9 MPa for the ER adhesive and 19.1 ± 5.2 MPa for the universal adhesive. After 24 months, the SBS of the ER adhesive was significantly higher for 5 wt.% MA-POSS-8 (17.9 ± 5.1 MPa) than for the control group (14.6 ± 3.6 MPa) and 10 wt.% MA-POSS-8 (12.8 ± 4.1 MPa), and more cohesive failures were observed. The SBS of the universal adhesive increased during aging, irrespective of the MA-POSS-8 concentration. 5 wt.% MA-POSS-8 improves the SBS of the ER adhesive and does not impair the SBS of the SE adhesive. Full article

Class II cavity preparation was conducted on 84 recently extracted premolars. Group I consisted of teeth restored with composite and without adhesive, (n = 12). Group II consisted of teeth restored with composite using prime and bond universal adhesive (n = 36). Group III teeth were restored with composites with Scotchbond universal adhesive (n = 36). Group II and III (n = 18 each) were further subdivided into chitosan pretreated and non-pretreated groups and named as II a, II b, III a, and III b, respectively. Microleakage was tested using the fluid filtration model. The mean microleakage was least for the prime and bond universal groups pretreated with chitosan (0.00145 and 0.00205) at both time periods. This was followed by the Scotchbond universal group pretreated with chitosan group (0.00149 and 0.00203). This was followed by the prime and bond without pretreatment with chitosan groups (0.00229 and 0.00225). Full article

The development of multifunctional materials has been expected in dentistry. This study investigated the effects of a novel universal bond containing a bioactive monomer, calcium 4-methacryloxyethyl trimellitic acid (CMET), on odontoblast differentiation in vitro. Eluates from bioactive universal bond with CMET (BA (+), BA bond), bioactive universal bond without CMET (BA (−)), and Scotchbond Universal Plus adhesive (SC, 3M ESPE, USA) were added to the culture medium of the rat odontoblast-like cell line MDPC-23. Then, cell proliferation, differentiation, and mineralization were examined. Statistical analyses were performed using a one-way ANOVA and Tukey’s HSDtest. The cell counting kit-8 assay and alkaline phosphatase (ALP) assay showed that cell proliferation and ALP were significantly higher in the 0.5% BA (+) group than in the other groups. In a real-time reverse-transcription polymerase chain reaction, mRNA expression of the odontogenic markers, dentin sialophosphoprotein (DSPP) and dentin matrix protein-1 (DMP-1), was significantly higher in the 0.5% BA (+) group than in the BA (−) and SC groups. Calcific nodule formation in MDPC-23 cells was accelerated in the BA (+) group in a dose-dependent manner (p < 0.01); however, no such effect was observed in the BA (−) and SC groups. Thus, the BA bond shows excellent potential for dentin regeneration. Full article