The journal of adhesive dentistry最新文献

Purpose: To measure the tip diameter (mm) and the ability to cover the anterior and posterior large restorations, radiant power (mW), radiant exitance (mW/cm2), emission spectrum (mW/cm2/nm), radiant exposure (J/cm2), the effect of the design on the access to the mouth posterior region, the temperature rise inside the pulp of three light-curing units (LCUs) and a new LCU available in the Brazil.

Methods and materials: Four LCUs that cost over US$900, three well-established (Bluephase G2, Ivoclar Vivadent; VALO Grand, Ultradent; and VALO Cordless, Ultradent), and a new LCU (Quazar, FGM) were tested in standard mode (20 s for all LCUs), high mode (3 s for VALO Cordless, 5 s for Quazar, and 20 s for Bluephase G2), and Xtra power mode (3 s for VALO Grand). The radiant power (mW) and emission spectrum (mW/nm) were measured using an integrating sphere connected to a fiberoptic spectroradiometer. The internal tip diameter (mm) of each LCU was measured using a digital caliper and was used to calculate the radiant exitance (mW/cm2). Radiant exitance profiles at the light tip were measured using a laser beam profiler. The radiant exposure (J/cm2) was calculated. The in vitro temperature rise produced by LCUs inside the pulp cavity of molar teeth was measured using a thermocouple. The mouth access of the LCU tip on the occlusal surface of the first mandibular molar tooth with two mouth openings of 25 mm and 45 mm at the incisors was evaluated. The cost of each LCU in Brazil was correlated with internal tip diameter, radiant power, and radiant exitance.

Results: All the LCUs were multiple-peak LCUs, and a uniform output. Quazar, VALO Cordless, and VALO Grand could maintain a perpendicular position regardless of mouth interincisal opening, while the Bluephase G2 required a tip angulation of 31.6 degrees at the 25 mm interincisal opening. The VALO Grand and VALO Cordless produced the highest temperature rise in standard mode ( 2.5°C), while in high mode, all LCUs produced lower temperature increases that use 5 s for Quazar and 3 s for VALO Grand and VALO Cordless, except for Bluephase G2, which produced a higher temperature rise ( 2.0°C) when activated for 20 s. There was a positive correlation between the cost of these LCUs and their averaged radiant power, diameter and the radiant exitance.

Conclusions: The LCUs tested emit light in the blue and violet spectra, characterizing them as multiple peaks. The temperature increases in the produced pulp remained within safe thermal limits ( 2.5°C), although standard-mode exposures produced higher pulp temperature rises. Bluephase G2 created higher angulation at 25 mm of interincisal mouth opening. The Quazar LCU produced a light output that was comparable to that from leading LCUs.

Purpose: Surface treatment of zirconia before cementation can be performed using different methods, e.g. airborne particle abrasion (APA) or various etching protocols. This study evaluated the effect of storage time between surface treatment and cementation on the surface free energy (SFE) of zirconia, the bond strength of composite cement, and failure mode.

Materials and methods: Rod-shaped zirconia specimens were fabricated and assigned to two surface treatment groups: APA (n = 80) and hot etching with potassium hydrogen difluoride (KHF2, n = 80). Each group was divided into four storage time subgroups: immediate, 24 h, 1 week, and 1 month. After storage, specimens were either analyzed for SFE (n = 10) or cemented for shear bond strength (SBS) testing and failure mode evaluation (n = 10).

Results: Two-way analysis of variance (ANOVA) showed a significant effect of both surface treatment and storage time on SFE (P 0.05), with KHF2-etched zirconia exhibiting the highest values across all time points. In both groups, SFE gradually decreased with increased storage. Surface treatment did not significantly affect SBS (P > 0.05). Storage time significantly influenced SBS (P 0.05), specifically for KHF2-etched zirconia; post-hoc comparisons showed higher SBS after 1 week than at immediate testing (P 0.05). Although adhesive failures to cement increased with longer storage time for KHF2-etched specimens, this trend was not significant (P > 0.05). For APA specimens, the highest incidence of adhesive failures (n = 9) to cement occurred after 24 h of storage.

Conclusion: Given the significant decrease in SFE with prolonged storage and adhesive failures to zirconia tended to increase over time, minimizing the interval between surface treatment and cementation is recommended.

Purpose: This in vitro study was designed to assess the influence of KATANA™ Cleaner (KC) on the microshear bond strength (μSBS) of composite resin restorations to saliva-contaminated dentin surfaces at various stages of the bonding process using a two-step self-etch adhesive system.

Materials and methods: A total of 140 sound human molars were randomly assigned into 14 groups according to the timing of saliva contamination and the decontamination approach. Saliva contamination was introduced at critical phases of adhesive application (before primer, after primer, after bond application, and after bond polymerization). KC was used for surface decontamination where applicable. Clearfil SE Bond adhesive and Filtek Z250 composite resin were applied using standardized procedures. μSBS test was performed after 24-h water storage, and failure modes were analyzed using stereomicroscopy. Additionally, dentin surfaces were evaluated under SEM. EDS was employed to evaluate the structure of the adhesive surface. Data were statistically analyzed using one-way ANOVA and LSD post hoc tests (α = 0.05).

Results: A significant difference in μSBS was observed among the groups (P = 0.029). The highest μSBS (29.5 ± 9.25 MPa) was recorded in the group that was contaminated after primer application and subsequently decontaminated with KC prior to bonding, surpassing even the uncontaminated control group. Decontamination following contamination after polymerization also led to significantly improved μSBS (26.5 ± 10.78 MPa). Groups without any decontamination exhibited significantly lower μSBS. Predominantly cohesive (in composite resin) and mixed failure modes were observed in high-strength groups, while adhesive failures were more common in low-strength groups.

Conclusion: KC significantly improved the μSBS of composite resin in saliva-contaminated dentin, particularly when applied after primer or post-polymerization contamination. These findings support the clinical use of KC as an effective decontamination protocol to maintain bonding performance under compromised isolation.

Purpose: This study evaluated the effects of etching mode, pH, and composition on the shear bond strength of three universal adhesives (UAs), in comparison with conventional adhesives.

Materials and methods: Crowns from 110 extracted third molars were sectioned to obtain 220 dentin surfaces and allocated into 11 groups (n = 20) based on adhesive system (OptiBondFL, ClearfilSE Bond, All-Bond Universal, OptiBond Universal, G2-Bond Universal) and etching mode (etch-and-rinse [ER], self-etch [SE], selective dentin etching [SDE]). Each group was divided into pre- and post-aging sub-groups. Shear bond strength was tested at 24h and after 5,000 thermal cycles. The resin-dentin interface was examined using scanning electron microscopy (SEM). Data were analyzed using one-way ANOVA, LSD post-hoc and paired-sample t-tests (α = 0.05).

Results: All-Bond Universal exhibited the highest bond strength across all modes, while OptiBond Universal showed the lowest. No significant difference was observed between ER and SE modes for most UAs, except G2-Bond Universal. SDE did not result in significantly higher bond strength compared to SE or ER in any group. After aging, G2-Bond Universal in SE mode exhibited the highest bond strength.

Conclusion: Bond strength was influenced by etching mode, pH, and composition of the adhesive. UAs performed comparably to the gold-standard SE adhesive in SE mode; however, their performance in ER mode varied depending on their composition and pH.

Clinical relevance: To ensure predictable clinical outcomes, clinicians should recognize that UAs do not perform uniformly. Selecting both the adhesive and etching mode according to the adhesive's composition may enhance long-term bonding success.

Purpose: This study evaluated the effects of incorporating urethane tetramethacrylate (UTMA) monomers and inorganic nano-fillers on the bonding performance and mechanical properties of a next-generation one-step universal adhesive, Clearfil Universal Bond Quick 2 (UBQ2), with a focus on clarifying its improvements over the previous formulation.

Materials and methods: Five adhesive systems were investigated: UBQ2, two experimental variants lacking either UTMA (UBQ2-U) or nano-fillers (UBQ2-F), the predecessor adhesive (Clearfil Universal Bond Quick, UBQ), and a gold-standard two-step self-etch adhesive (Clearfil SE Bond 2, SE2). Microtensile bond strength (μTBS), bond layer thickness (L), ultimate tensile strength (UTS), and water sorption (Wsp) were evaluated.

Results: UBQ2 demonstrated significantly higher UTS and lower Wsp than UBQ2-U (P 0.001 and P = 0.03, respectively), indicating enhanced mechanical resilience and hydrolytic stability due to the presence of UTMA. Compared to UBQ, UBQ2 showed improved mechanical properties while maintaining comparable μTBS. The absence of nano-fillers (UBQ2-F) significantly reduced μTBS (P 0.05), confirming their critical role in bonding performance. Despite forming a thinner adhesive layer, UBQ2 achieved dentin bond strength comparable to SE2.

Conclusion: By combining UTMA and nano-fillers, UBQ2 has improved wettability compared to conventional products, while also providing high bonding performance and mechanical properties with a one-step application. These findings support the development of universal adhesives through simplified clinical protocols and improved material properties.

Clinical relevance: This study demonstrates that incorporating nano-fillers and UTMA into a one-step universal adhesive (UBQ2) enhances mechanical strength, reduces water sorption, and maintains high dentin bond strength. Clinically, UBQ2 offers a simplified yet reliable bonding performance comparable to SE2.

Purpose: To evaluate whether single-day, gamified training (called 'Battle of the Bonds') improves operators' immediate macro dentin shear bond strength (SBS) values and perceived learning in undergraduate and continuing dental education about dental adhesives, composite resin, and light-curing units.

Materials and methods: In July 2025, 14 dentists and 21 final-year students performed four macro-SBS tests before and eleven after lectures on adhesive systems, composite selection, and light-curing. SBS was measured on human dentin for each participant's routine adhesive and representatives of all actual adhesive/generation families (from three-step etch-and-rinse to universal adhesives). Post-course satisfaction was measured using a 13-item Likert questionnaire (ranging from 1 to 5). Paired and independent t-tests were used to compare the SBS (α = 0.05).

Results: The baseline SBS with the participants' own adhesive was similar between the dentists and the students (12.5 ± 6.4 MPa vs 13.1 ± 6.6 MPa, P = 0.68). After training, the mean SBS with the participants' own adhesive significantly increased to 18.5 ± 6.3 MPa for the dentists (+67%) and to 17.3 ± 6.0 MPa for the students (+27%) (both P 0.05). Satisfaction with training and perceived knowledge gains were very high (4.9 ± 0.5 for dentists and 4.9 ± 0.3 for students).

Conclusions: A single-day, competition-based curriculum that couples concise lectures with hands-on SBS testing yields rapid, clinically meaningful improvements and strong engagement across predoctoral and practitioner audiences. This experiential format may help standardize technique-sensitive restorative skills in dental education.

Purpose: This study aimed to evaluate the effects of bioactive, inorganic, and organic fillers on the curing time, mechanical properties, mineralization ability, and shear bond strength to dentin of 4-methacryloxyethyl trimellitate anhydride/methyl methacrylate-tri-n-butylborane (4-META/MMA-TBB) resin-based restorative materials.

Materials and methods: Experimental resins were prepared by incorporating 3 wt% organic composite filler, bioactive glass, or aluminosilicate glass into 4-META/MMA-TBB resin. A commercial organic-filler-containing 4-META/MMA-TBB resin (Bondfill SB Plus (BSP)) was also tested for comparison. The curing time, three-point flexural strength, and shear bond strength to root dentin were measured and statistically analyzed with a significance level of α = 0.05. The mineralization ability of groups containing bioactive glass was evaluated based on the formation of hydroxyapatite in simulated body fluid.

Results: The bioactive glass group exhibited prolonged curing times and reduced flexural strengths compared to BSP. Bioactive glass induced slight mineralization. Organic composite filler reduced the curing time and significantly increased the shear bond strength to dentin. After thermal cycling, the organic composite filler groups retained higher bond strengths than the other groups.

Conclusion: Incorporating organic composite fillers into 4-META/MMA-TBB resin may improve clinical handling by reducing the curing time while maintaining or enhancing the bond strength to dentin, suggesting their suitability for restorative applications, particularly in moisture-compromised environments.

Purpose: This prospective crossover clinical study evaluated the effectiveness of different moisture control methods on intraoral humidity and examined the influence of external environmental humidity.

Materials and methods: Forty adult participants (31 females, 9 males; mean age 36.6 ± 11.3 years) were enrolled. Intraoral relative humidity was measured above anterior and posterior teeth under four randomized conditions: control (mouth breathing), rubber dam isolation, vacuum-assisted isolation (ZOO), and saliva ejector. External humidity was recorded simultaneously and categorized as high (≥60%) or low (60%).

Results: Both rubber dam isolation and vacuum-assisted isolation significantly reduced intraoral humidity compared with the saliva ejector and control. Under low external humidity, rubber dam and vacuum-assisted isolation achieved the lowest intraoral humidity (all P 0.001). Under high external humidity, all methods reduced humidity compared with control, but vacuum-assisted isolation remained significantly more effective than the rubber dam and saliva ejector. External humidity showed a strong correlation with intraoral humidity in the rubber dam group (ρ up to 0.77, P 0.001).

Conclusion: Moisture control methods differ in their ability to reduce intraoral humidity, with rubber dam and vacuum-assisted isolation providing the most effective reduction. However, high external humidity significantly increases intraoral humidity regardless of the isolation method, indicating that clinicians should consider both the isolation strategy and environmental conditions when aiming to minimize intraoral humidity.

Purpose: To evaluate the influence of functional monomer type and powder-to-liquid ratio on the interfacial properties and degree of conversion of experimental self-adhesive flowable resin composites (SAFRCs) bonded to dentin.

Materials and methods: Nine experimental SAFRC formulations were developed by varying the powder-to-liquid ratio (1.9, 2.2, 2.5) and the functional monomers included (10-MDP, GPDM, HEMA). Human molars (n = 27) were restored using each formulation and analyzed using a rheometer to assess viscosity, Raman micro-spectroscopy for inter-diffusion zone (IDZ) width, and degree of conversion at the interface (DC%). Two-way ANOVA and post-hoc tests were performed for statistical analysis (α = 0.05).

Results: Rheological testing revealed, as expected, non-Newtonian flow behavior in all composites, with significant effects of both powder-to-liquid ratio (P 0.001) and monomer type (P 0.001) on viscosity. 10-MDP composites exhibited optimal viscosity (1.12-2.86 mPa·s) across all ratios, significantly lower than GPDM and HEMA. Raman mapping showed a distinct IDZ with hybrid characteristics for 10-MDP formulations, contrasting with abrupt transitions or gaps in GPDM and HEMA groups. IDZ width was significantly greater in 10-MDP formulations (P 0.0001). The DC% at the interface was highest for 10-MDP and HEMA formulations, exceeding 68%, while GPDM composites showed lower values (P 0.001).

Conclusion: Functional monomer type critically affects the interfacial bonding performance and conversion rate of SAFRCs, with 10-MDP outperforming GPDM and HEMA in interdiffusion and adhesive quality. Variations in powder-to-liquid ratio influenced viscosity but had a limited impact on interfacial performance. Optimized formulations with 10-MDP may enhance the clinical efficacy of SAFRCs.

Clinical relevance statement: Refining acidic-monomer chemistry and viscosity in SAFRCs could improve their bonding predictability.

Purpose: The popularity of Biodentine (Septodont) use for vital pulp therapies requires verifying its bonding ability to other restorative materials. The null hypotheses were that different restorative materials and adhesive strategies did not influence shear bond strength (SBS) to Biodentine, nor its setting time.

Materials and methods: 204 plastic molds were filled with Biodentine, half set for 12 min, and the rest for 7 days. Specimens were divided into six groups according to the strategy and material used to restore over Biodentine (n = 17): (1) SE: Universal adhesive application in self-etch mode; (2) ER: Universal adhesive in etch-and-rinse mode; (3) Bur: Roughening with a bur followed by SE; (4) AO: Airborne-particle abrading with Al2O3 particles before SE; (5) RMGIC: Restoration with a resin-modified glass-ionomer; (6) SARC: Restoration with a self-adhesive resin cement. Groups 1 to 4 were restored with a flowable bulk-fill composite. Specimens were subjected to SBS, and the mode of failure was determined. Five additional specimens were evaluated under SEM-EDX. Data were analyzed with Kruskal-Wallis and U-Mann-Whitney tests (P 0.05).

Results: AO and SARC groups showed 100% pretest failures. At 12 min setting, the RMGIC group and Bonferroni correction achieved the lowest SBS values. At a 7-day setting, the Bur group registered the lowest SBS, and the groups restored with universal adhesive achieved the highest values. SBS results for the Bur and RMGIC groups were influenced by the setting time.

Conclusion: Bur roughening or alumina airborne-particle abrading did not improve Biodentine adhesion to composite resin restorations, whereas the application of a universal adhesive achieved the highest SBS results regardless of the evaluated setting time.