The journal of adhesive dentistry最新文献

Purpose: To investigate the dye penetration distance at Class V tooth-restoration margins/interfaces prepared in the labora-tory and orally using a primerless wet technique and MMA-TBB bonding resin with or without 4-META monomer promoter.

Materials and methods: A box-form cavity at the cementoenamel junction was prepared on extracted human premolars and vital teeth scheduled for extraction for in-vitro and in-vivo studies, respectively. For each vital cavity, 1% citric acid and 1% ferric chloride aqueous (1-1) conditioner was applied for 10 s, 30 s, or 60 s, rinsed off and blot-dried, and was then bonded with either 4-META/MMA-TBB or MMA-TBB resin and bulk-filled with light-cured composite resin (n = 10). Restored vital teeth continued to function in the oral cavity for seven days before extraction. Restorations were stored in water at 37°C and 0.5% basic fuchsin dye solution for 24 h each before dye penetration measurement under a microscope, while a hybrid layer was observed using a scanning electron microscope (SEM).

Results: No hypersensitivity or pain occurred in any vital teeth. For all 1-1 groups, no dye penetration was detected at any margins of the in- vitro restorations. Dye penetration (0.13 mm) was only observed in one intraoral restoration of 60 s etching with MMA-TBB resin at the cementum/dentin margin. A consistent hybrid layer after chemical modification was observed in leakage-free specimens.

Conclusion: The results suggest that the 1-3 µm 1-1 demineralized substrate clinically provides sufficient permeability to form a microleakage-free hybrid layer using a primerless wet technique with MMA-TBB or 4-META/MMA-TBB resin. Intraoral microleakage-free restorations may lead to longer-term restored-tooth survival.

Purpose: To modify phosphoric acid (PA) with polyphenol-rich plant extracts and verify their effect on immediate (24 h) and long-term (1 year) micro-shear bond strength (µSBS) of an adhesive system to sound and eroded dentin.

Materials and methods: 420 dentin specimens (360 for µSBS and 60 for characterization) were prepared and divided into two substrate-subgroups: sound (untreated) and eroded dentin (underwent 10 cycles of 1 h exposure to human saliva and 5 min immersion in citric acid). The specimens from each subgroup were randomly distributed into six groups, according to PA (n = 30/group): PA-EXP (experimental control), PA-GSE (PA-EXP + grape seed extract), PA-BLU (PA-EXP + blueberry extract), PA-CRA (PA-EXP + cranberry extract), PA-GRE (PA-EXP + green tea extract), PA-COM (commercial control). After etching with the respective PA (15 s), specimens were restored with adhesive and composite resin. Half of the specimens of each group were subjected to µSBS testing after 24 h and the other half after 1 year of storage (tap water, 37°C). Analyses were made with three-way ANOVA and post-hoc Tukey tests (α = 0.05).

Results: Higher µSBS was observed to sound dentin than to eroded dentin, regardless of the storage time, except for PA-BLU and PA-GSE after 1 year (p = 0.40 and p = 0.10, respectively). After 24 h, for both substrates, PA-COM presented statistically significantly lower µSBS than the other PAs. After 1 year, µSBS was significantly reduced for all groups except for the PA-COM (sound: p = 0.67; eroded: p = 0.13).

Conclusion: Compared to the commercial PA, the modified PAs improved the immediate µSBS and gave similar long-term µSBS to sound as well to eroded dentin.

Purpose: The current trend in denture adhesives is shifting toward zinc-free formulations due to the significant health concerns associated with zinc. Studies have focused on the retention of these zinc-free denture adhesives; however, there is a dearth of literature regarding their damping performance. This study analyzes the impact of oral cavity physiological parameters: temperature, pH, and swelling ratio on the mechanical properties of zinc-stabilized and zinc-free denture adhesives and examines the role zinc plays in influencing the adhesive behavior. This study investigates how underlying mechanical properties of adhesive cream change for zinc-stabilized and zinc-free denture adhesives. The relative damping and its variation from exposure to physiological conditions in the oral cavity can significantly assist in the design of dentures to reduce the discomfort experienced by denture wearers.

Materials and methods: The relative damping of the zinc-stabilized and zinc-free denture adhesives was investigated with the loss modulus values, which were evaluated using rheological frequency sweep tests. The tests were performed by maintaining the denture adhesives at specified values of temperature, pH, and swelling ratio, and over a frequency range of 0.01 Hz to 10 Hz, which included the average frequencies of human chewing / bite forces reported in existing literature.

Results: Zinc-stabilized denture adhesive showed a larger fluctuation of loss modulus values compared to the zinc-free formulation with respect to pH, temperature, and swelling ratios. The zinc-free denture adhesive showed higher damping behavior at frequencies below 0.7 Hz, whereas the zinc-stabilized denture adhesive showed higher damping behavior above loading frequencies of 0.7-1 Hz. Both the adhesives showed varying behavior on either side of the bite force spectrum in terms of relative damping of the applied bite.

Conclusions: The damping or cushioning effect provided by denture adhesives can reduce pain experienced and assist dental practitioners in better supporting denture wearers.

Purpose: The aim of this study was to evaluate the marginal quality and wear of bulk-fill composite resins (BFs) for Class-II restorations of primary and permanent molars in comparison to a conventionally layered composite resin (RC) and to compare the results of the two dentitions.

Materials and methods: Eighty (40 primary and 40 permanent) extracted molars received standardized Class-II cavity preparations and were restored with either one of two flowable BFs, one of two high viscous BFs, or a composite resin (RC). Thermomechanical loading (TML; 2,500 cycles +5°C/+55°C; 100,000 cycles, 50N, 1.67Hz) followed. A quantitative marginal analysis using SEM images and a profilometric quantification of two-body wear were carried out using replicas. ANOVA, Kruskal-Wallis, Mann-Whitney U, and Wilcoxon signed-rank tests were used for statistical analysis (P < 0.05).

Results: For both dentitions, a significant reduction of perfect margins was observed after TML (P < 0.02). For the primary dentition, the flowable BFs showed significantly less perfect margins than all high viscous materials (P < 0.005). For the permanent dentition, RC showed significantly fewer gaps than the flowable BFs (P < 0.04). Regarding wear, within the dentitions, no significant differences could be computed between groups with regard to the maximum height loss (P < 0.05).

Conclusion: All of the investigated bulk-fill composite resins showed satisfactory in-vitro results for both tested parameters in primary and permanent teeth, with a superiority of the high-viscosity materials in terms of marginal quality.

Objective: To evaluate the effect of pre-procedural antiseptic mouthwashes on dentin bond strength of different adhesive systems.

Methods: Flat occlusal dentin surfaces from 120 extracted human molars were randomly divided into four groups according to mouthwashes (0.12% chlorhexidine = CHX, 1% hydrogen peroxide = HP, 0.2% povidone-iodine = PI, and no mouthwash/control) and three subgroups of adhesives used (Clearfil SE Bond; CSE, Single Bond Universal = SBU in etch-and-rinse (ER) or self-etch (SE) modes) (n = 8). Composite resin was built up, and all bonded teeth were stored in 37°C distilled water for 24 h. Stick-shaped specimens were prepared and subjected to microtensile bond strength (µTBS) test. Failure mode analysis was determined using a light microscope. A resin-dentin interface was observed using scanning electron microscopy (SEM, n = 2). Elemental analysis in the PI group was further examined by SEM with energy-dispersive X-ray spectroscopy. The µTBS data were statistically analyzed by two-way analysis of variance (ANOVA) and Duncan's multiple comparison (P < 0.05).

Results: Rinsing with PI followed by SBU-SE demonstrated significantly higher µTBS than the control group (P < 0.05). Rinsing with HP showed significantly lower bond strength for CSE (P < 0.05). However, the effect of adhesive systems was not observed for all mouthwashes used (P > 0.05). SEM/EDX revealed the iodine deposition in the underlying dentin, where the highest amount of iodine was found for SBU-SE.

Conclusion: CHX and PI can be recommended as pre-procedural antiseptic mouthwashes since they show no negative impact on µTBS for all tested adhesives. The dentin bond strength of CSE is hampered in the HP mouthwash group, and this should be a concern for the use of self-etching adhesive afterward.

Purpose: The purpose of this laboratory study was to evaluate common materials for isolation and neutralizing agents for hydrofluoric acid (HF). Additionally, surfaces of lithium disilicate ceramic were examined for precipitates after the etching and neutralizing process.

Materials and methods: The HF permeability of the following isolation agents (n=8) was investigated by positioning them over pH indicator paper under airtight conditions and applying 9% HF: latex rubber dam; elastic plastomer rubber dam; nitrile gloves; latex gloves; liquid rubber dam; Teflon; AZ strip. Four neutralizing agents were tested (n = 8): calcium carbonate plus chlorhexidine gel; calcium hydroxide; calcium D-gluconate monohydrate plus chlorhexidine gel; IPS neutralizing powder plus water. Each agent was mixed with HF, according to a calculated ratio, followed by determining the pH value. Forty lithium disilicate ceramic specimens were divided into five groups (n=8), according to the etching and neutralizing protocol, and examined for precipitates by scanning electron microscopy (SEM) and energy-dispersive X-ray (EDX) analysis.

Results: All isolation agents were impermeable to HF, except for Teflon. HF could be neutralized with neutralizing agents under laboratory conditions, with mean central pH values ranging from 6 to 11. Assessment with SEM showed precipitates on surfaces when neutralizing with calcium hydroxide only. EDX analysis confirmed residues of calcium fluoride among others.

Conclusion: All tested isolation agents, except for Teflon, seem suitable for clinical use. When using calcium hydroxide for neutralizing, precipitates could remain on the surface of lithium disilicate ceramic.

Purpose: To assess the influence of operator, tool, dental loupes, and tooth position on enamel loss and composite remnants after removal of composite attachments (CA) for orthodontic clear aligners. Procedure duration was also analyzed.

Materials and methods: Eight maxillary resin dental arches with four natural teeth were placed in the right posterior sector in dental simulators, and CA was realized. The dental arches were randomly distributed according to three experimental factors: operator (junior, senior), tool (tungsten carbide bur and silicone polisher, only silicone polishers), and use of dental loupes. Dental arches were scanned with 3D profilometry before and after CA removal to measure enamel surface height variation (ESHV), particularly enamel loss in the CA area. Digital microscopy was used to detect composite remnants.

Results: The mean enamel loss was -22.7 ± 29.4 µm (range -132 to 0 µm). It was not significantly influenced by experimental factors or tooth position. Composite remnants were found in 34.4% of teeth, significantly more in senior than in junior operators (p = 0.038). They were more frequent with silicone polishers than with tungsten carbide burs (p = 0.0005) and were reduced using dental loupes (p = 0.0090). Junior operators worked faster than senior operators (p = 0.031), but the latter were quicker when using the dental loupes (p = 0.012).

Conclusion: Aligner CA removal induces enamel damage or leaves composite remnants on its surface. The presence of composite remnants is influenced by the type of tool and can be reduced by using dental loupes, which also lowers working time.

Purpose: To evaluate the survival and clinical quality of individually layered indirect composite restorations (ICRs) in the mixed and permanent dentition at two study centers.

Materials and methods: A total of 155 adhesively cemented ICRs in 34 participants (aged 6 to 50 years and treated between 2008 and 2018) were evaluated for survival and clinical quality. All were individually layered restorations fabricated from laboratory sculptable composites by a specialized dental technician. Two calibrated independent investigators examined and graded each restoration as success, survival with repair, or failure based on the FDI criteria. The marginal quality and gap width of the restorations were analyzed by scanning electron microscopy. The periodontal health of treated teeth (TT) was evaluated in comparison with that of unrestored control teeth (CT) by measuring the pocket depth (PD), clinical attachment level (CAL), sulcus bleeding index (SBI), and the modified Turesky Plaque Index (TPI). A serial t-test (p 0.05) was used for statistical analysis of periodontal parameters. Success and functional survival rates were calculated using the Kaplan-Meier method.

Results: Molar incisor hypomineralization (MIH) was the most common indication for treatment (41%). The median age at treatment was 14.9 years (68%-CI: 7.7-29.5). The median service time of the restorations was 5.7 ± 3.4 years. 132 restorations were classified as a success, 21 as survival with repair, and 1 as a failure. The success rates at 1, 5, and 10 years were 95.4%, 87.4%, and 78.8%, respectively, and the corresponding functional survival rates were 100.0%, 98.9%, and 98.9%. The clinical quality, encompassing esthetic, functional, and biological criteria, was rated as excellent or good in over 90%. Periodontal response, however, was the only criterion showing worse results since restored teeth (TPI = 1.9) had significantly more plaque than CT (TPI = 1.7; p = 0.0001). No significant differences were observed in PD, CAL, or SBI. The mean marginal gap width was 135.7 µm and 63.8% of the restorations had perfect margins.

Conclusion: ICRs are suitable for minimally invasive restoration of large tooth structure defects in the developing dentition of children and adolescents and for long-term temporary restoration of the adult dentition.

Purpose: This study aimed to develop a novel orthodontic primer that incorporated graphite fluoride (GF) and Bioactive glass (BAG) and to investigate its cell viability, bonding strength, and enamel damage, as well as its antibacterial and remineralization properties.

Materials and methods: Nine groups were prepared by adding different concentrations of GF (1, 2, and 4 wt.%) and BAG (1, 3, and 5 wt.%) to Transbond™ XT orthodontic primer. The prepared primers were compared to the control primer in terms of cell viability, shear bond strength (SBS), adhesive remnant index (ARI), enamel damage index (EDI), and antibacterial test. Then, the groups with better antibacterial properties (GFBAG 1-1, GFBAG 4-1, GFBAG 4-3, GFBAG 4-5) were evaluated for the remineralization properties.

Results: All the prepared orthodontic primers with different concentrations of GF/BAG revealed acceptable cell viability levels, with comparable SBS and ARI values to the control primer (p>0.05). Simultaneously, the EDI was reduced, while the antibacterial properties were significantly enhanced when compared to the control group (p0.05). The result of remineralization properties revealed that the selected groups had significantly higher remineralization ability than the control group; this was most pronounced in the GFBAG 4-3 group.

Conclusions: All the prepared GF/BAG orthodontic primers are biologically safe with adequate SBS, ARI, and EDI values for clinical application with enhanced antibacterial properties. The GFBAG 4-3 experimental primer reveals the best antibacterial and remineralization properties which require further in-vitro and in-vivo investigations as a preventive measure of white spot lesions.

Purpose: To evaluate interfacial three-dimensional adaptation and internal voids of different flowable materials before and after cyclic fatigue in a simulated deep-margin elevation scenario.

Methods: Eighty (n = 80) extracted premolars were selected and two Class II cavities were prepared. The mesial one with cervical margin 1 mm above the cementum-enamel junction (CEJ) and the distal one with cervical margin 1 mm below the CEJ. After performing adhesive procedures, specimens were divided into four groups according to the employed materials for 2 mm horizontal deep-margin relocation: nanohybrid composite (Clearfil ES2, Kuraray); conventional viscosity flowable composite (Tetric Flow, Ivoclar); medium viscosity flowable composite (Majesty ES2 Low Flow, Kuraray); high viscosity flowable composite (Majesty ES2 Super Low Flow, Kuraray). All restorations were finalized by oblique layering with nanohybrid composite (Clearfil ES2, Kuraray). To reveal interfacial and internal gap progression, specimens were scanned with a micro-CT (SkyScan 1172), before and after 500,000 cycles of mechanical chewing simulation (50 N, 1 Hz). Data were imported into Mimics software after smoothing and region growing. Only the 2 mm margin relocation volumes were considered. Obtained masks were analyzed for noise removal and volume calculation. At baseline, interfacial gap progression and internal voids, expressed in mm3, were collected and statistically analyzed with two-way ANOVA (α 0.05) for the variables substrate and restorative materials followed by Tukey post-hoc test. An additional two-way ANOVA test, followed by Tukey post-hoc test, was performed to evaluate variation in interfacial gap progression after mechanical aging.

Results: At baseline, the ANOVA test showed a significant difference for the variable restorative materials (p = 0.01). More specifically, the Tukey post-hoc test revealed that the highly filled medium viscosity composite performed better than the conventional viscosity composite at baseline for the interfacial gap. The internal voids ANOVA test at baseline reported no significant differences for the variable tested. Analysis of variance for internal gap progression after thermocycling showed no differences for both substrate and restorative material employed.

Conclusions: Highly filled medium viscosity composite performed significantly better than the conventional viscosity flowable composite for what concern baseline interfacial gaps. Artificial aging with a chewing simulator and thermocycling did not affect interfacial gap progression on enamel and dentin. The tested restorative materials performed equally after aging.