American journal of dentistry最新文献

Purpose: To evaluate the adhesion of Candida albicans and the mechanical properties of resins in denture bases fabricated using conventional, milled, and 3D printing methods at different aging times.

Methods: A total of 96 resin samples were manufactured, divided into three resin groups (n=32) (conventional thermally activated, milled and 3D printed), and subdivided into four aging times by thermocycling at temperatures 5± 1°C and 55 ± 1°C in 24 hours, 5,000, 10,000, 20,000 cycles (n= 8), evaluating the adhesion of C. albicans (ATCC90028), surface microhardness (Knoop), flexural strength and elastic modulus by three-point mechanical test. Data were evaluated by two-way ANOVA and Tukey's test for multiple comparisons (P< 0.05).

Results: The milled resin demonstrated significantly lower colonization of C. albicans at times T0 (0.50± 1.37) (P= 0.007) and T1 (0.60±1.33) (P= 0.032) compared to other resins. The 3D-printed resin exhibited significantly lower values of surface microhardness at T1 (11.05± 0.26), T2 (10.92±0.63), and T3 (10.21± 0.45) (P< 0.001). The conventional and 3D-printed resins did not show significant differences in flexural strength over time (P> 0.05). The 3D-printed resin exhibited a significant difference in elastic modulus compared to the other resins, notably displaying the lowest value at time T3 (750.36± 29.32 MPa) (P< 0.05).

Clinical significance: Denture base materials compatible with the CAD-CAM system are increasingly available, leading to a rise in the use of dentures fabricated with this technology. This study provided promising evidence for CAD-CAM system denture base materials.

Purpose: To evaluate the effects of four different mouthwashes, including three desensitizing formulations, one chlorhexidine-based solution, and artificial saliva as the control, on enamel discoloration and surface roughness.

Methods: 60 extracted human lower incisors were exposed to the solutions, and measurements were performed before and after exposure using a spectrophotometer (ΔE) and profilometer (Ra).

Results: None of the tested solutions caused clinically perceptible discoloration (ΔE < 3.7) nor significant changes in the surface roughness (P> 0.05). Among the desensitizing solutions, the potassium nitrate-containing mouthwash exhibited the highest, albeit not clinically significant, changes in both color and roughness. However, no statistically significant differences were observed among the groups in terms of both ΔE and surface roughness values (P> 0.05).

Clinical significance: Desensitizing mouthwashes can be safely recommended for routine use in managing dentin hypersensitivity without causing visible discoloration or roughness alterations. However, clinicians should remain mindful of potential long-term effects and advise patients accordingly.

Purpose: To review the literature on the application potential of ultrasound in the treatment of various oral and dental diseases.

Methods: Two reviewers carried out a computer-based literature search using PubMed and Web of Science to identify papers published up to February 2025. The keywords used in the investigation were "therapeutic ultrasound", " low-intensity pulsed ultrasound", and various words related to oral and dental disease (oral submucosal fibrosis, burning mouth syndrome, periodontitis, orthodontic tooth movement, and tooth trauma or caries).

Results: Therapeutic ultrasound, particularly low-intensity pulsed ultrasound (LIPUS), showed beneficial effects in interfering with pathological fibrosis, suppressing inflammatory responses, promoting periodontal tissue regeneration, and facilitating the repair of dentin-pulp complex injuries in oral and dental diseases.

Clinical significance: Therapeutic ultrasound, particularly low-intensity pulsed ultrasound (LIPUS), showed beneficial effects in interfering with oral and dental diseases and may become an important adjunctive treatment modality in oral and dental medicine in the future.

Purpose: To evaluate the laboratory effects of commonly used beverages on the surface roughness and color change of leucite-reinforced Computer Aided Design-Computer Aided Manufacturing (CAD-CAM) material with different laboratory surface finishes.

Methods: In this study, all the IPS Empress CAD-CAM ceramic block specimens were treated with a glaze layer and then randomly divided into three groups. The samples (n=25) in Group 1 (Control) were not treated (glaze layer was left). The glaze layer of the other samples (n=50) was abraded by the same researcher. While the samples in Group 2 were treated with Optrafine (optrafine after glazing); those in Group 3 were subjected to surface treatment with Eve polishing kits (Eve kit after glazing). The samples were then immersed in five different beverages (cola, coffee, tea, fruit juice and distilled water) and color (ΔE₀₀) and surface roughness (Ra) measurements were repeated after 18, 36 and 54 hours. Color measurements of all specimens were measured using a dental spectrophotometer and surface roughness (Ra values) through profilometry.

Results: ANOVA revealed that the interactions of time, time and surface finishing protocols, time and solution, and the combination of time, surface finishing process, and solution were statistically significant (P< 0.001). The least color change (ΔE₀₀= 0.16) and smoothest surfaces (Ra= 0.38) µm were observed in samples with the glaze surface finishing protocol, while the highest color change (ΔE₀₀=2.54) and surface roughness (Ra=2.17 µm) values were found in samples with the Eve surface finishing protocol. The leucite-reinforced CAD-CAM ceramic samples with a glazed surface finish showed the highest color stability and the lowest surface roughness. Color change was measured within clinically acceptable limits in all groups (AT, ΔE₀₀≤ 1.8 ), except for Eve surface-finished tea group (2.54) between 18-36 hours.

Clinical significance: The esthetic and functional quality of prosthetic restorations is closely related to the surface properties of CAD-CAM ceramic materials. Clinicians must be familiar with the properties and performance of various CAD-CAM materials to make the best choice for their patients.

Purpose: To compare the optical characteristics of 3D-printed resins and conventional resin composites, focusing on color differences, whiteness index, and translucency under varying specimen thicknesses and polishing conditions.

Methods: A total of 240 disc-shaped specimens (10 mm diameter, 2-4 mm thickness) were prepared using four brands each of 3D-printed resins and resin composites. Color measurements (L*, a*, b*) were performed using a benchtop spectrophotometer before and after polishing. Color differences (ΔE₀₀) were calculated using the CIEDE2000 formula, and both whiteness index and translucency were assessed. Statistical analyses included paired t-tests and Kruskal-Wallis tests (P< 0.05).

Results: Significant color differences were observed among the different brands, even with identical shade designations and polishing conditions. Polishing reduced ΔE₀₀ values but most remained above the acceptability threshold. Resin composites exhibited smaller color differences than 3D-printed resins, while comparisons between the two types showed the largest discrepancies. Translucency decreased with increasing specimen thickness and varied significantly across materials, with 3D-printed resins generally showing higher whiteness indices. The findings suggest a need for greater standardization of optical properties in esthetic restorative materials.

Clinical significance: Substantial color and translucency differences exist among materials with identical shade designations. Clinicians should consider these variations to ensure esthetic consistency, highlighting the need for improved standardization in restorative materials.

Purpose: To evaluate the shear bond strength of restorative resin agents incorporating the antibacterial monomer methacryloyloxy-dodecylpyridinium bromide (AM-MDPB) when bonding IPS Empress 2 ceramic restorations to dentin.

Methods: 216 all-ceramic IPS Empress 2 discs (3 mm diameter, 4 mm height) were prepared with various dual-polymerizing (DP) luting systems, including Panavia F 2.0 and Variolink 2, to cement these restorations to prepared dentin surfaces. The study assessed the impact of a dentin adhesive solution with AM-MDPB (Clearfil Protective Adhesive, CPA) on the shear bond strength of these restorations. Human premolars (n=216) were prepared to expose the dentin surface, which was polished with silicon carbide sandpaper. Specimens were randomly divided into four groups based on luting system and application of CPA. Shear bond strength was measured after thermal cycling, and failure modes were analyzed using an Image Analyzer. The data were analyzed using two-way ANOVA.

Results: The findings demonstrated a significant enhancement in the shear bond strength of all DP luting systems to dentin with the application of the antimicrobial adhesive. The mean shear bond strength (SBS) values in MPa for Panavia F 2.0, Panavia F 2.0 with CPA, Variolink 2, and Variolink 2 with CPA were 18.11 ± 2.98, 25.40 ± 7.46, 21.45 ± 4.75, and 29.32 ± 2.37, respectively. Most samples exhibited adhesive failure at the interface between the restorative resin agent and dentin.

Clinical significance: The study confirmed that the use of Clearfil Protective Adhesive in dual polymerizing techniques effectively increases the shear bond strength of IPS Empress 2 ceramic restorations to dentin without compromising the integrity of the bonded interface.

Purpose: To analyze the effect of dentifrices containing different desensitizing agents on dentin wear and tubule occlusion.

Methods: Dentin slabs from sound human third molars were assigned to six groups (n=10 per group): C- (negative control, distilled water), C+ (regular fluoride dentifrice, without desensitizing agent), SCP (sodium and calcium phosphosilicate/Novamin), ACZP (arginine, calcium carbonate/Pro-Argin and zinc phosphate), FCPS (calcium fluoride phosphosilicate/Biomin), and AC (Pro-Argin). A 5-day erosion/abrasion cycling was conducted, consisting of citric acid exposure (1%, 2 minutes) followed by remineralization by artificial saliva (60 minutes), six times per day and a twice-daily toothbrushing (45 strokes). Surface loss (SL) was measured using an optical profilometer at baseline, and after days 1, 3, and 5. Dentin tubule occlusion was evaluated via environmental scanning electron microscopy (n= 3) at baseline and after the final cycle. Data were statistically analyzed (α= 0.05).

Results: No significant differences in surface loss (SL) were observed among dentifrices on days 1 and 3 (P> 0.05), but significant differences emerged by day 5 (P< 0.05). SL increased significantly over time (P< 0.001). For tubule obliteration, no significant differences were found among dentifrices (P= 0.101) or in the interaction between dentifrice and time (P= 0.131), although significant differences were observed over time (P< 0.001). All dentifrices promoted a progressive increase in surface loss (SL) over time. No significant differences were observed among groups on days 1 and 3. By day 5, FCSP and AC showed significantly lower SL compared to the negative control. However, this reduction in SL was not associated with significant differences in dentin tubule occlusion.

Clinical significance: Desensitizing dentifrices should aim to promote tubule occlusion while avoiding any contribution to the advancement of erosive tooth wear.

Purpose: To test the in vitro effectiveness of GOx-combined nanoparticles (pvp-Cu-GOx) in treating oral cancer cells under hydrogen peroxide and laser irradiation conditions.

Methods: Using polymer, metal, and glucose oxidase, nanoparticles were synthesized. Their ability to kill cancer cells was evaluated through an in vitro cell viability test. Methylene blue (MB) degradation test and DPBF assay were performed to evaluate ROS generation. Oxygen production and glucose consumption were also evaluated.

Results: GOx-combined nanoparticles (pvp-Cu-GOx) achieved cancer cell death over 80% in 100 µM H₂O₂. Much degradation of MB solution occurred by pvp-Cu-GOx compared to that of pvp-Cu. Oxygen was produced up to 4.3 mg/L by pvp-Cu-GOx at 200 ppm concentration. pvp-Cu-GOx consumed glucose though not high compared to that by glucose oxidase itself. The obtained results are the combined reactions of ROS and glucose oxidase.

Clinical significance: GOx-combined nanoparticles pvp-Cu-GOx can significantly lower in vitro cancer cell viability in 100 µM H₂O₂. pvp-Cu-GOx has great potential to be used in clinical applications after passing in vivo verification.

Purpose: To evaluate the effect of whitening mouthwashes with different active ingredients on the color change (ΔE₀₀) of a stained resin composite.

Methods: A total of 70 resin composite samples (G-aenial Anterior) with dimensions of 8 х 2 mm were prepared. The samples were immersed in coffee for 14 days to simulate time-dependent color change, then randomly assigned into seven groups (n=10). Listerine Advanced White (LAW), Splat White Plus (SWP), Colgate Optic White (COW), Colgate Plax White + Charcoal (CPC), Global White Charcoal Extra Whitening Mouthwash (GWE), R.O.C.S Black Edition Whitening Mouthwash (ROC), and distilled water (DW) were used over a 12-month period. Color measurements were performed at baseline, after staining, and after 1 month, 3 months, 6 months, and 12 months of use.

Results: Resin composite exhibited discoloration exceeding the 50:50% acceptability threshold (AT) (ΔE₀₀: 1.8) after 14 days of coffee immersion. Group, immersion period, and their interaction significantly affected the ΔE₀₀ values (P< 0.001). All whitening mouthwashes except SWP reduced the color change on resin composite below the AT, while COW achieved this level after 1 month of use, LAW and CPC after 3 months of use, and GWE and ROC after 12 months of use. The effectiveness of whitening mouthwashes in improving the color of stained resin composite varies depending on the formulation of the whitening mouthwash and immersion time. All whitening mouthwashes except SWP were effective in improving the color of resin composite.

Clinical significance: The color improvement effect of whitening mouthwashes on resin composite may be affected by the specific formulation and duration of use of whitening mouthwash.

Purpose: To evaluate the efficacy of low and high-concentrated bleaching gels in both at-home and in-office techniques and their effects on enamel properties.

Methods: Bovine enamel/dentin specimens were randomly allocated to five groups (n=12): deionized water (negative control - DW), 6% hydrogen peroxide (6HP), 40% hydrogen peroxide (40HP), 10% carbamide peroxide (10CP), and 45% carbamide peroxide (45CP). For 6HP and 40HP, the gel was applied 3x20 minutes in 1 day. For 10CP and 45CP, the bleaching gels were applied 1x/day for 8 hours and 1x/day for 30 minutes over 7 days, respectively. Before and after bleaching treatment, color (CIE L*a*b*), surface microhardness (SMH), roughness (Ra), and gloss (GU) were assessed. Alterations in color (ΔE₀₀ and ΔWID), SMH (%SMHalt), Ra (%Raalt) and GU (%GUalt) were calculated. Data were analyzed by one-way ANOVA and Tukey's test (α= 0.05).

Results: Significant differences were found for color alteration (P< 0.05). The group 10CP showed the highest color difference. The groups 40HP, 10CP, and 45CP exhibited similar values of ΔWID. No alteration in enamel microhardness and roughness was found (P> 0.05). Although significant differences were found for %GUalt between the groups (P< 0.05), they were not different from the negative control. The 10% carbamide peroxide resulted in the highest color alteration, while all tested bleaching gels were effective in producing color change that exceeded the acceptability threshold without causing damage to the enamel surface.

Clinical significance: All bleaching gels can be considered safe in the tested protocol, and the greatest color difference was promoted by 10% carbamide peroxide overnight.