American journal of dentistry最新文献

Purpose: To evaluate the bonding interface and the remineralization potential of a bioactive restorative material on demineralized dentin compared to a conventional bulk-fill resin composite restoration.

Methods: Twelve caries-free human molars were used in this study. Specimens were randomly divided into two groups according to the type of restorative material used (n=12); an injectable resin-modified glass-ionomer restorative [Activa BioActive-Restorative (ABR) ] and a bulk-fill composite [3M Filtek One Bulk Fill Restorative, (BFC) ]. Each restored specimen was sectioned in two semi-equal halves along the long axis of the teeth perpendicular to the resin dentin interface with a water-cooled diamond disk at low speed. The restoration-dentin interfaces were scanned under SEM to observe micromorphological analysis; then an elemental analysis of the interface was performed using an energy dispersive X-ray (EDX) spectroscopy.

Results: Quantitative data were described using median (minimum and maximum) after testing normality using the Shapiro-Wilk test. Mann-Whitney U test was used to compare the BFC and ABR. Higher mean values of Ca were identified and related to the ABR material, which provided more Ca ions than BFC. The comparison of Ca and P between materials showed a significant difference in the amount of Ca provided by ABR versus BFC. ABR restorations presented a thicker, and superior remineralization interface compared to the bulk-fill resin composite.

Clinical significance: Activa BioActive Restorative restorations presented a thicker and superior remineralization interface compared to the bulk-fill resin composite.

Purpose: To evaluate the role of improvement in inflammatory oxidative stress by periodontal therapy (NSPT) in chronic kidney disease (CKD) subjects.

Methods: 50 stable subjects of CKD (stage III-IV) and having chronic periodontitis were enrolled for the present study. Group A (control group) subjects who did not receive NSPT and Group B (test group) subjects who received NSPT. Oral hygiene instructions were given to both groups, malondialdehyde (MDA) in gingival crevicular fluid (GCF) and serum, albumin creatinine ratio (ACR), urine protein creatinine ratio (UPCR), pocket depth (PD), clinical attachment loss (CAL), plaque index (PI), gingival index (GI), Interleukin 1-beta (IL-1β), high sensitivity C-reactive protein (hs-CRP) in serum were assessed at baseline and 6 months.

Results: There was a significant difference observed in PD, CAL, PI, GI and MDA-GCF, hs-CRP, IL-1β in serum following NSPT in the test group compared to the control group at 6 months follow up. Within the limitations of the study, the results revealed that NSPT can be used as an effective method to reduce inflammatory oxidative stress in CKD subjects and improve renal health. Further well-designed longitudinal trials with larger sample size and longer follow ups are needed.

Clinical significance: The non-surgical periodontal intervention showed statistically significant improvement on oxidative and inflammatory stress markers in gingival crevicular fluid and serum in subjects suffering from chronic kidney disease which suggests that periodontal treatment may be beneficial for these subjects.

Purpose: To evaluate the effect of material type, material thickness and cement shade on the final color of two different ceramic/glass-polymer-based CAD-CAM blocks over colored abutments.

Methods: Tested blocks (Vita Enamic-VE and Cerasmart-Cs) were cut in three different thicknesses (1, 1.5 and 2 mm), and cemented on two different shaded (B1 and C3) resin discs with three shades (A2-Universal, W-White, T-Translucent) of a self-adhesive resin cement. An additional 10 specimens were prepared for control (n= 370). 36 subgroups were formed to simulate different clinical conditions (n= 10). The final color difference (ΔE₀₀) was recorded as the difference between material-cement-resin composite assembly and control specimens on a black background according to the CIEΔE 2000 color difference formula. Clinical perceptibility (0.80) and acceptability thresholds (1.80) were used to evaluate the results. Data were analyzed using the Kruskal-Wallis and the Mann-Whitney U non-parametric tests at P< 0.05 significance level.

Results: ΔE₀₀ results were influenced by the polymer-based CAD-CAM material type, material thickness, and cement shade (P< 0.05) over both abutment shades. VE exhibited lower ΔE₀₀ values than Cs over B1 and C3 shaded abutments (for each abutment P< 0.001). Specimens of 1 mm thickness exhibited significantly higher ΔE₀₀ than the 2 mm or 1.5 mm specimens (P< 0.001), and W cement shade demonstrated higher ΔE₀₀ than T or A2 shades (P< 0.001) over both shaded abutments.

Clinical significance: The final color of the polymer-based CAD-CAM restoration can be improved by the suitable combination of material/material thickness/cement shade to achieve the desired esthetic outcomes within clinically acceptable limits. Regardless of the type of polymer-based CAD-CAM material chosen, at least 1.5 mm restoration thickness with the use of Translucent or A2 cement shade is recommended for masking whitened or darkened shaded abutment teeth in clinical practice.

Purpose: To compare the effects of different thicknesses of ceramic veneering on the light transmission of various monolithic zirconia and lithium disilicate materials used in esthetic restorations.

Methods: Zirconia (i.e., Katana UT, Katana HT, Prozir Diamond, Prozir HT, and Zenostar MO) and lithium disilicate specimens (i.e., Emax HT and Emax MO) were prepared at thicknesses of 0.5 mm, 0.8 mm, and 1.2 mm. Additionally, 0.8 mm-thick specimens and 0.3 mm-thick ceramic veneer were prepared for veneering groups. The total transmittance of light values were measured using a spectrophotometer. The light transmission values were analyzed using the Kruskal-Wallis and the post-hoc Dunnett tests (α= 0.05).

Results: The Emax HT group defined significant differences from all groups (P< 0.05) at all thicknesses. The mean total transmittance of light ranged from 5.53% to 19.55%. There was no significant difference between the Katana UT and Prozir Diamond groups at the 0.5 mm, 0.8 mm, and 1.2 mm thicknesses (P> 0.05).

Clinical significance: The results of this study showed no significant effects of veneering ceramic on the light transmittance of the specimens at a thickness of 0.8 mm. Novel monolithic zirconia materials may be preferred over porcelain veneering in 0.8 mm-thick restorations, as the esthetic appearance of the restorations would not change.

Purpose: To evaluate and compare the bonding of flowable resin composites and light-cured resin cements to dental ceramics.

Methods: Grit-blasted zirconia plates were primed with MDP-containing adhesive. Lithium disilicate glasses plates were etched with HF and primed with silane. Two flowable resin composites with high (CM: 75 wt%/62 vol%) and low (BF: 67.3 wt%/47 vol%) filler contents, and two resin cements, again with high (C: 72 wt%/69 vol%) and low (R: 66 wt%/47 vol%) filler contents, were bonded to both types of pretreated ceramics. Shear bond strength (SBS) was measured after 24 hours water storage or 10,000 times thermocycling between 5 and 55°C. The viscosities and film thicknesses of the four resin-based luting agents (RBLAs) were also explored by rotational rheometer and metallurgical microscope severally.

Results: Different RBLAs provided statistically different SBS values, with the high-filler specimens exhibiting higher SBS values than the low-filler specimens. The viscosities decreased in the order C > R > BF > CM. The film thicknesses for the BF and C groups were higher than those of the CM and R groups.

Clinical significance: This study provides evidence that flowable resin composites with high filler contents and low viscosities may serve as an alternative to light-cured resin cements for luting zirconia or lithium disilicate glass. This expands the range of light-cured luting agents available for bonding of veneers or other thin restorations, which is of great benefit to clinical practice.

Purpose: To evaluate and compare in vitro and in vivo color parameters of hybrid ceramic, resin nanoceramic, and artificial acrylic resin teeth.

Methods: For the in vitro stages, 120 specimens (2 mm) were prepared from Vita Enamic (VE), Lava Ultimate (LU), CeraSmart (CS), and acrylic teeth (IV), and immersed in coffee, red wine, and distilled water for 24, 72, and 144 hours. For the in vivo stage, 16 individuals received a complete denture that had upper premolars made of VE, LU, CS blocks, and IV. The color was measured at 1, 3, and 6 months. Color difference (ΔE₀₀), translucency (TP), and contrast ratio (CR) were obtained using a spectrophotometer. Shapiro Wilk, one-way ANOVA, and repeated measures ANOVA were used for statistical analysis.

Results: ΔE₀₀ of VE and LU were higher than CS and IV (P< 0.05). ΔTP of VE and LU were lower than CS and IV (P< 0.05). ΔTP of CS was higher in red wine compared to coffee. ΔCR of CS and IV were increased with prolonged immersion (P< 0.001). ΔE₀₀ and ΔCR were similarly affected in coffee and red wine. All discolorations were higher than clinical acceptability (ΔE₀₀> 1.77). For in vivo stages, ΔE₀₀ of VE and LU increased over time (P< 0.01). No difference was detected between in vivo and in vitro ΔE₀₀ of CS (P> 0.05). ΔE₀₀ of VE, LU, and IV was higher in in vitro stages. LU and VE showed lower color stability; their use in esthetic regions is questionable. The prolonged immersion increased discoloration. Coffee and red wine had a similar effect on discoloration and opalescence. Discoloration in laboratory conditions did not correspond to the clinical discoloration according to the new method presented in this study.

Clinical significance: The use of CAD-CAM blocks for endocrowns is rising; however, Lava Ultimate and Vita Enamic showed lower color stability, thus, their use in esthetic regions is questionable. This is the first study that investigates the discoloration of CAD-CAM blocks in clinical use. Discoloration in laboratory conditions did not correspond to the clinical discoloration.

Purpose: To evaluate the influence of brushing with a specific antiseptic soap solution on the surface (roughness and hardness) and biological properties of a specific hard chairside reline resin.

Methods: The hard chairside reline resin specimens were made and distributed to the following groups according to disinfectant solution: sodium hypochlorite 0.5% (SH), Lifebuoy solution 0.78%; experimental group (LS) and phosphate-buffered saline PBS to be submitted to the brushing cycle for 10 seconds. The roughness and hardness were assessed before and after the cycle. For the biological properties, the colony-forming unit and Alamar Blue assays were performed. For all the properties evaluated the sample size consisted of nine specimens. The data were submitted to two-factor ANOVA (surface properties) and one-way ANOVA (biological properties) and Tukey's post-test with a significance level of 5% (α= 0.05).

Results: The Lifebuoy group did not present a statistical difference (P> 0.05) in relation to the other groups for the evaluated surface properties. Furthermore, the Lifebuoy solution showed a statistically significant difference (P> 0.05) in relation to the negative control in the reduction of biofilm on the resin and no significant difference (P> 0.05) was observed when compared to the positive control group. Thus, it was concluded that brushing with the Lifebuoy soap solution did not interfere with the surface properties of the hard chairside reline resin, and was able to reduce the biofilm of C. albicans.

Clinical significance: Disinfectant liquid soap can be used for brushing of relined removable dentures as a simple, low-cost, and effective method for removing the biofilm.

Purpose: To evaluate the antiplaque effects for 0.454% bioavailable gluconate chelated stannous fluoride (SnF₂) dentifrices versus controls by clinical model, plaque index, tooth surface and tooth type in a pooled analysis.

Methods: Randomized controlled trials (RCTs) were conducted to evaluate plaque effects of SnF₂ dentifrices from the same formulation family over the past 30 years. Forty-four 4-day and longer-term (≥ 2 weeks) RCTs conducted in six countries with 3,336 subjects using Turesky Modified Quigley-Hein Plaque Index, Rustogi Modification of the Navy Plaque Index, Digital Plaque Imaging Analysis, and Silness and Löe Plaque Index were included.

Results: In 13 and 11 longer-term studies assessing SnF₂ dentifrice versus a negative or positive control, respectively, standardized differences in average plaque score of -1.15 (95% CI: -1.61, -0.69) and -0.74 (95% CI: -1.20, -0.28) were observed (P ≤ 0.011), favoring SnF₂. Reductions represented a 19% and 16% benefit versus the negative and positive control, respectively. In 18 and five 4-day studies assessing SnF₂ dentifrice versus a negative (NaF/SMFP) or positive (triclosan/chlorhexidine) control, respectively, differences in average 4-day plaque score of -0.27 (95% CI: -0.31, -0.23) and -0.15 (95% CI: -0.25, -0.06) were observed (P≤ 0.001) favoring SnF₂. Reductions represented a 14% and 11% benefit versus the negative and positive control, respectively. Significant antiplaque benefits for SnF₂ dentifrice were seen regardless of clinical model, plaque index, tooth surface or type, including brushed and unbrushed surfaces (P≤ 0.049).

Clinical significance: Bioavailable gluconate chelated SnF₂ dentifrices showed consistent plaque inhibition versus negative and positive controls across all conditions evaluated. Importantly, the effect on unbrushed surfaces illustrated the significant plaque inhibition benefit of SnF₂ beyond mechanical plaque removal.

Purpose: To test the feasibility of nitrogen-doped TiO₂ nanoparticles in the killing of Streptococcus mutans (S. mutans) for short term treatment.

Methods: For the study, S. mutans were treated with the combinations of N-TiO₂, visible light, and without/with 0.5% H₂O₂ inclusion. Visible light was irradiated for 3 minutes one time.

Results: Methylene blue solution was degraded (bleached) 5-30% by one of N-TiO₂ (or TiO₂) + visible laser (405 or 660 nm) +0.5% H₂O₂ conditions owing to almost linearly producing free radicals through photocatalysis. Antibacterial outcomes treated with N-TiO₂ were slightly better than those by TiO₂ regardless of test condition. Also, killing of S. mutans treated with 405 nm laser was slightly better than those by 660 nm laser.

Clinical significance: S. mutans can be eliminated using N-TiO₂ with clinically acceptable light (wavelength, intensity) and low concentration H₂O₂ condition under short term treatment.

Purpose: To devise a method for artificial biofilm formation using Porphyromonas gingivalis, Tannerella forsythia, Treponema denticola, and Streptococcus gordonii, as well as a method for evaluating the effects of various ingredients on the artificial biofilm.

Methods: An artificial biofilm was developed using P. gingivalis, T. forsythia, T. denticola, and S. gordonii, which was then observed using scanning electron microscopy and evaluated by microflora analysis. The artificial biofilm was exposed to chlorhexidine gluconate and stained with a fluorescent dye. Then, the fluorescent-stained biofilm was observed using a confocal laser microscope and measured using a fluorescent microplate reader.

Results: The microflora analysis confirmed that the culture medium developed was capable of culturing four different bacterial species at the same time. The distribution of dead bacteria differed according to the difference in the concentration of exposed chlorhexidine gluconate. Moreover, the rate of attachment of viable cells decreased in a concentration-dependent manner. Many bacteria were detached from the biofilm in the group exposed to 0.09% chlorhexidine gluconate. Exposure to chlorhexidine gluconate induced a concentration-dependent decrease in living microorganisms and an increase in dead microorganisms in the biofilm.

Clinical significance: The results of this study revealed that S. gordonii, P. gingivalis, T. forsythia, and T. denticola could be used to develop artificial biofilms. The effects of chlorhexidine gluconate on the biofilm showed that evaluating the change in the artificial biofilm caused by the component effect in the experiments was possible via exposure to chlorhexidine gluconate. This method can efficiently evaluate the component effect and has a high potential for use as an indicator. This study demonstrated that this simulation could help develop preventive measures.