Operative dentistry最新文献

The purpose of this study was to investigate the effect of chitosan-added experimental nanohydroxyapatite (n-HA) gel on the physical and morphological changes of the enamel surface after the use of two different vital bleaching agents. Fifty-two intact, caries-free human maxillary incisors were embedded in acrylic resin. Chitosan-added n-HA powder was synthesized using a high-temperature oxidation method and then mixed with phosphate-buffered saline solution (PBS) to form a gel. The teeth were divided into four groups: Group B: Biowhiten in-office 40% n-HP (BioWhiten, Biodent Ltd, Istanbul, Turkey); Group O: Opalescence Boost 40% HP (Ultradent Products Inc., South Jordan, UT, USA); Group BN: Biowhiten in-office 40% n-HP+n-HA gel; Group ON: Opalescence Boost 40% HP+n-HA gel. Color change, surface microhardness, and surface roughness (Ra) measurements were taken before, immediately after, and one week after bleaching. Three specimens from each group were also subjected to scanning electron microscopy/energy dispersive X-ray spectroscopy (SEM/EDS) analysis. The data were statistically analyzed using an analysis of variance (ANOVA) and Bonferroni post hoc test (p<0.05). After bleaching, all groups showed a noticeable change in color (p<0.05), but with no differences among the treatment groups (p>0.05). After bleaching, the highest Ra values were determined in Group O (p<0.05). Group ON showed a statistically lower Ra value than Group O (p<0.05). The lowest microhardness value after bleaching was observed in Group O (p<0.05), which also had the lowest calcium/phosphorus (Ca/P) value. After the experimental chitosan-added n-HA gel application, the Ca/P ratio increased. The use of experimental chitosan-added n-HA gel after bleaching improved the physical and morphological properties of the enamel surface without reducing the effectiveness of bleaching.

Objective.: This study evaluated the effect of filler content and composition on the radiopacity of different resin-based materials used to cement fiberglass posts (dual-cure resin cements or dual-cure resin core materials) and build the core (bulk-fill or dual-cure core resin composites) to restore endodontically treated teeth.

Methods and materials.: Nine resin-based materials were tested: Four dual-cure resin core materials: Allcem Core, FGM; LuxaCore Z, DMG; Rebilda DC, VOCO; and Clearfil DC Core Plus, KURARAY; three dual-cure resin cements: RelyX Universal, 3M Oral Care; RelyX U200, 3M Oral Care; and Allcem Dual, FGM; and two bulk-fill resin composites: OPUS Bulk Fill APS, FGM; and Filtek One Bulk Fill, 3M Oral Care. Thermogravimetric analysis (TGA, %) was performed to determine the filler content. Scanning electron microscopy (SEM) and energy-dispersive X-ray spectroscopy (EDS) were used to evaluate the filler morphology and composition. Radiopacity was measured using digital radiographs (n=10) according to ISO 4049 standards. TGA and radiopacity data were subjected to a one-way analysis of variance (ANOVA) followed by a Tukey post hoc test (α=0.05).

Results.: Except for Luxacore Z, the dual-cure resin core materials and bulk-fill resin composites had higher filler contents than the dual-cure resin cements (p<0.001). Allcem Core exhibited more homogeneous fillers without agglomerates, whereas RelyX Universal presented only nanoparticles. OPUS Bulk Fill APS, Allcem Dual, and Allcem Core, made by the same manufacturer, presented similar sizes, shapes, and distributions of filler content. EDS analysis revealed that oxygen O (8), Si (14), C (6), Al (13), and Ba (56) were the most prevalent elements. The radiopacity of the tested materials is related to the presence of high atomic number elements such as Yr (70), La, (57), Ba (56), Zr (40), Sr (38), and Br (35) in their filler composition. All materials satisfied the ISO 4049 radiopacity requirements.

Conclusions.: Results were product-specific. Except for LuxaCore Z and Allcem Core, dual-cure resin core materials exhibited filler content similar to that of bulk-fill resin composites and higher than that of dual-cure resin cements. All materials exceeded the ISO 4049-2019 standard for radiopacity of restorative materials.

This comparative in vitro study evaluated surface treatment methods for chairside CAD/CAM lithium disilicate enriched with virgilite using atomic force microscopy (AFM) imaging. Specimens were fabricated from two lithium disilicate materials: the traditional material (IPS e.max CAD, Ivoclar Vivadent, Schaan, Liechtenstein) and a virgilite-containing material (CEREC Tessera, Dentsply Sirona, Charlotte, NC, USA). Surface roughness (Ra) [in micrometers (μm)] was quantitatively assessed with AFM. The results demonstrated that IPS e.max CAD with glazing exhibited the smoothest surface with the lowest Ra values (10.03 ± 5.03 μm). In contrast, CEREC Tessera exhibited the highest surface roughness when treated with glazing (51.98 ± 12.31 μm), while the zirconia polishing system provided a smoother surface (15.44 ± 9.69 μm).

Objectives: Simplified application and caries preventive features are desired properties for an ideal dental restorative material. Therefore, the aim of this study was to evaluate the clinical performance of a newly developed bioactive alkasite-based resin composite (Cention Forte, Ivoclar Vivadent, Schaan, Liechtenstein) with these properties.

Methods: Vital teeth with class I or II restoration need were included in the study. A total of 49 patients received 90 posterior restorations. Extension for retention and beveling were avoided during cavity preparation. The primer (Cention Primer, Ivoclar Vivadent) for alkasite restorative materials was applied prior to restoration placement. Two independent observers made the evaluations using the FDI criteria (scores 1-5) for esthetic, functional, and biological properties. Patients were recalled after three to four weeks (baseline) and one year. Wilcoxon signed rank test was used to evaluate the differences between FDI scores at baseline and after one year.

Results: Ninety restorations at baseline and 86 restorations at one year were evaluated. The overall success rate of the restorations was 98.8%, and the overall survival rate was 100% after one year in function. Only one restoration was clinically unacceptable (FDI score 4) due to a small material chip after one year.

Conclusions: Quality of the restorations was unaffected in terms of marginal adaptation, marginal discoloration, and secondary caries formation, whereas color and surface luster of the restorations deteriorated slightly over time. No retention loss or tooth fracture was observed.

This study investigated the color stability and surface roughness of universal chromatic resin-based composites (RBCs) after immersion in detox juices. One hundred seventy-six disc-shaped specimens (8 mm in diameter and 2 mm in thickness) were prepared using four universal chromatic RBCs: NeoSpectra ST (NS), Omnichroma (OM), Charisma Topaz One (CO), and G-ænial Universal Injectable (GI). Specimens of each material were randomly divided into four subgroups (n=11) and immersed in either the assigned detox juices (red, green, or yellow) or distilled water (control). Color and surface roughness measurements were taken at baseline, 15 and 30 days of immersion. Scanning electron microscopy (SEM) was used to evaluate the surface topography of the composites. The color change [CIEDE2000 (ΔE00)] and surface roughness (Ra) values were analyzed using generalized linear models and multiple comparison tests with Bonferroni correction. Correlation analysis was performed using Spearman rank correlation test. The main variable effects of "composite and immersion media" were significant for both color change and surface roughness parameters (p<0.001). Additionally, the main effect of the "evaluation period" was significant only for surface roughness (p=0.001). The highest discoloration occurred in the GI group immersed in a red beverage, while the CO group immersed in yellow beverage had the highest Ra values. In SEM analysis, OM demonstrated a more homogeneous filler structure with clearly visible nano-spherical fillers and nanoclusters, contributing to its superior smoothness. Conversely, a significant increase in rough areas was observed, especially in NS exposed to the green beverage and CO exposed to the yellow beverage, after 30 days. While the immersion of resin composites in detox juices induced an acceptable color alteration except for OM and GI groups immersed in the red beverage, all tested materials exhibited clinically admissible results regarding surface roughness.

The aim of this study was to investigate whether different concentrations of acacia extract could improve the biological stability of dentin collagen. Slice (n=3) and beam (n=5) samples of dentin obtained from human third molars were demineralized and treated with the following solutions: G1 (control)-deionized water; G2- 1% acacia extract; G3-2% acacia extract; and G4-3% acacia extract. The dentin slices were analyzed by Fourier transform infrared (FTIR) spectrophotometry to observe their interactions with collagen. The beams were submitted to digestion with type I bacterial collagenase solution, and the percentage of weight was calculated to evaluate the resistance to enzymatic biodegradation. The Adper Scotchbond Multipurpose adhesive system was applied on the flat dentin surfaces according to the manufacturer's recommendations (G1). In groups G2, G3 and G4, acacia extract at concentrations of 1%, 2%, and 3%, respectively, were applied after acid etching. A resin composite block was built on the adhesive, and the teeth were cut to obtain beams (n=7 teeth; ~12 beams per tooth) with cross-sectional areas of approximately 0.8 mm2. Half of the specimens were submitted to the microtensile bond strength (μTBS) test in a universal testing machine at a crosshead speed of 0.5 mm/min, and the other half were submitted to the μTBS test after six months of storage in distilled water. FTIR analysis showed the interactions of the three concentrations of acacia extract with collagen. According to ANOVA and Tukey tests, G1 had the highest biodegradation rate (100%), which was significantly higher than the rates of G2 (24%), G3 (23%) and G4 (17%) (p<0.05). According to twoway ANOVA and Tukey tests, only G1 showed a significant decrease in μTBS after six months of storage (p<0.05). It was concluded that 1%, 2%, and 3% acacia extract all interacted with human dentin collagen, reduced collagen biodegradation and favored the stabilization of the bonding interface at the six-month evaluation.

Objective: This study evaluated the influence of two types of glass ionomer-based luting agent on the clinical performance of metal-free zirconia crowns.

Methods and materials: Thirty participants received two full crown restorations in either anterior or posterior teeth, in a split-mouth design. After tooth preparation, impressions with addition-cured silicone were made and casts were obtained. The casts were scanned and 3Y-TZP zirconia copings (Ceramill ZI - Amann Girrbach) were milled using a CAD/CAM system. Glass ceramic (IPS E.max Ceram, Ivoclar Vivadent) was used to create the crown shape. For each participant, one crown was cemented using a conventional glass ionomer (GIC - Meron, Voco), while the other received a resin-modified glass ionomer cement (RMGIC - Meron Plus QM, Voco). The restorations were evaluated by two calibrated examiners after seven days, one year, and two years. The parameters at each evaluated time were analyzed by the Fisher exact test (α=0.05).

Results: At two years postoperatively, 24 participants attended the recall, and 46 (76.67%) restorations were evaluated. No fractures or secondary caries were diagnosed. Minimal marginal staining was verified in both cements. During the follow-up period, only two anterior crowns cemented with conventional glass ionomer showed loss of retention. No loss of retention was detected in posterior crowns.

Conclusion: After two years of intraoral service, the crowns cemented with either conventional glass ionomer cement or resin-modified glass ionomer presented acceptable and similar clinical performance for all parameters analyzed in both anterior and posterior teeth.

Objectives: The purpose of this study was to compare the curing light transmittance and depth of cure (DOC) of resin composite through clear polyvinyl siloxane (PVS) impression materials and 3D printed clear matrix materials at various thicknesses.

Methods and materials: Cylindrical specimens (n=6) of three clear PVS materials (Affinity Crystal, Clear Bite Matrix, Exaclear) were fabricated in Teflon molds, and two 3D-printed clear matrix materials (Filtek matrix, IDB 2) were printed into specimens of five different thicknesses (2 mm, 4 mm, 6 mm, 8 mm, 10 mm). To measure light irradiance transmittance, specimens were placed on a radiometer (CheckUp), allowing the transmitted irradiance from a light-curing unit (Elipar DeepCure-S, 1450 mW/cm²) to be recorded. DOC of resin composite specimens was measured by placing flowable composite (PVS and IDB 2) or heated conventional composite (Filtek Matrix) into a split metal die with a 4 mm diameter opening. The composite was cured through the different matrix specimens using the Elipar DeepCure-S curing light for the manufacturer's recommended curing time (10 seconds) or double the curing time (20 seconds). The DOC of the composite specimens was measured according to ISO 4049 7.8, and the percentage of total cure (%TC) was calculated by dividing by the total cure (DOC with no matrix and 10-second cure). The correlation between irradiance transmittance and %TC was analyzed with Pearson's coefficient. For each matrix material, the %TC was compared to the total cure of the material using a Dunnett's test. The compressive modulus of each material was measured and compared with a one-way ANOVA.

Results: There was a statistically significant, strong positive correlation between irradiance transmittance and %TC for 10 seconds (r=0.90 p<0.001) and 20 seconds (r=0.89 p<0.001). There was not a statistically different DOC for the total cure with Affinity (2 mm), Clear Bite (2 mm), Exaclear (2, 4, 6 mm), IDB2 (2, 4, 6, 8 mm), and Filtek Matrix (2,4 mm) if a 20-second cure was used.

Conclusions: Decreased light irradiance from curing through clear matrix materials decreases the DOC of resin composites. Doubling the curing time when curing through some matrix materials at certain thicknesses allowed a total cure.

The aim of this study was to investigate whether different concentrations of acacia extract could improve the biological stability of dentin collagen. Slice (n=3) and beam (n=5) samples of dentin obtained from human third molars were demineralized and treated with the following solutions: G1 (control)-deionized water; G2-1% acacia extract; G3-2% acacia extract; and G4-3% acacia extract. The dentin slices were analyzed by Fourier transform infrared (FTIR) spectrophotometry to observe their interactions with collagen. The beams were submitted to digestion with type I bacterial collagenase solution, and the percentage of weight was calculated to evaluate the resistance to enzymatic biodegradation. The Adper Scotchbond Multipurpose adhesive system was applied on the flat dentin surfaces according to the manufacturer's recommendations (G1). In groups G2, G3 and G4, acacia extract at concentrations of 1%, 2%, and 3%, respectively, were applied after acid etching. A resin composite block was built on the adhesive, and the teeth were cut to obtain beams (n=7 teeth; ~12 beams per tooth) with cross-sectional areas of approximately 0.8 mm2. Half of the specimens were submitted to the microtensile bond strength (µTBS) test in a universal testing machine at a crosshead speed of 0.5 mm/min, and the other half were submitted to the µTBS test after six months of storage in distilled water. FTIR analysis showed the interactions of the three concentrations of acacia extract with collagen. According to ANOVA and Tukey tests, G1 had the highest biodegradation rate (100%), which was significantly higher than the rates of G2 (24%), G3 (23%) and G4 (17%) (p<0.05). According to two-way ANOVA and Tukey tests, only G1 showed a significant decrease in µTBS after six months of storage (p<0.05). It was concluded that 1%, 2%, and 3% acacia extract all interacted with human dentin collagen, reduced collagen biodegradation and favored the stabilization of the bonding interface at the six-month evaluation.