American journal of dentistry最新文献

Purpose: To review the literature on the relationship of milk fat globule EGF and factor V/VIII domain containing (MFGE8) in periodontal osteoimmunology and the clinical significance of MFGE8 in periodontal disease.

Methods: Two reviewers carried out a computer-based literature search using PubMed, Scopus, and Web of Science to identify papers published up to November 2023. The keywords used in the investigation were "MFGE8" and various words related to periodontal disease (periodontal, periodontitis, gingival, gingivitis, gingiva, and periodontium).

Results: MFGE8 plays a critical role in the etiology of periodontal disease via regulating pro-inflammatory cytokines and bone cells. In addition, MFGE8 may be applied as a diagnostic biomarker and a therapeutic target in periodontal disease.

Clinical significance: MFGE8-mediated periodontal osteoimmunology fills the vacant part of the pathogenesis in periodontal disease. This review provides a comprehensive perspective on the potential of MFGE8 in periodontal disease therapy.

Purpose: To explore the latest trends in research on whitening toothpaste and to present the issues and future perspectives of these studies.

Methods: An initial PubMed search was performed, followed by a meticulous manual review. A total of 543 papers were initially retrieved, and 54 final research papers were selected and analyzed through a manual review.

Results: The number of studies on whitening toothpastes has significantly increased, and while initial studies primarily focused on the efficacy of various whitening toothpastes, recent studies have shifted towards investigating the potential effects on dental hard tissues such as enamel and dentin. Common active ingredients used in these whitening toothpastes include hydrogen peroxide, activated charcoal, and blue covarine. Most studies have used commercial toothpastes with fixed ingredients rather than experimentally manufactured toothpaste, and it was noted that toothpastes from specific major manufacturers were frequently used.

Clinical significance: Whitening toothpastes should be treated as separate entities based on their active ingredients, and more standardized experimental designs are required for better comparisons. Accurate analysis and labeling of other components of toothpaste are also essential.

Purpose: This study examined the effect of using KATANA Cleaner (KC) containing 10-methacryloyloxydecyl dihydrogen phosphate (MDP) salt on the micro-shear bond strength (µSBS) of a self-adhesive cement to uncontaminated and contaminated dentin.

Methods: Dentin samples were categorized into four contamination conditions (no contamination, saliva, blood, saliva/blood mixed) and subjected to two decontamination methods (water rinse and KC use), forming eight groups. Scanning electron microscope images representing each group were obtained. One sample representing each group was analyzed by Raman Spectroscopy. Composite resin was bonded to the sample dentin surfaces with a self-adhesive resin cement. After 5,000 thermal cycles, the µSBS test was performed. The data were analyzed statistically (α= 0.05).

Results: The lowest µSBS value was observed in the water-rinsed mixed contamination group, while the highest was in the KC-treated uncontaminated group. KC-treated groups exhibited significantly higher µSBS values compared to water-rinsed groups for each contamination type (P< 0.05), indicating the efficacy of KC in enhancing bond strength.

Clinical significance: There are limited studies using the new MDP salt-containing cleaner on dentin. In this study, contamination of dentin tissue with saliva, blood, and saliva/blood mixture was simulated and the effects of water rinsing and MDP salt-containing cleaner (KATANA Cleaner) on bond strength were tested as decontamination methods. The results showed that the use of a cleaner containing MDP salt increased the bond strength to dentin tissue under both non-contaminated and contaminated conditions.

Purpose: To compare charcoal-containing dentifrices (CDs) to non-charcoal containing dentifrices (NCDs) through the following experiments: potentially available fluoride, 1-minute fluoride release, pH, cytotoxicity, heavy metals, enamel fluoride uptake (EFU) and relative dentin abrasivity (RDA).

Methods: Nine fluoride dentifrices; six CDs and three NCDs were tested (n= 3) for available fluoride, the amount of fluoride released within 1 minute, pH cytotoxicity, heavy metals, EFU and RDA. Four CDs and 1 NCD contained sodium fluoride (NaF) as the active ingredient whereas two dentifrices contained stannous fluoride (SnF₂; 1 CD and 1 NCD), and two dentifrices contained disodium monofluorophosphate (Na₂FPO₃, or Na₂MFP; 1 CD and 1 NCD). Available samples were homogenized and diluted to 1-in-100 in deionized water (DIW). Release samples were prepared as 1-in-4 homogenized dilutions by mass in DIW. Available and release samples were measured in triplicate (n= 3) via fluoride ion-selective electrode (F-ISE) and ion chromatography (IC). ANSI/ADA 130 was followed for pH. L929 cells were cultured using the lactate dehydrogenase (LDH) assay and ISO 10993-5 Annex C MTT cytotoxicity test. Heavy metals testing was performed using a hydrofluoric acid digestion sample preparation method followed by inductively coupled plasma mass spectrometry (ICP-MS) detection. EFU was performed on enamel specimens that underwent treatment with a CD slurry (1-in-4 dilution) following Test Method #40 of FDA Monograph 21. RDA was performed following ISO 11609 Annex A and the Hefferren method. Data was analyzed using one-way ANOVA followed by post-hoc tests (α= 0.05).

Results: Available fluoride for all nine dentifrices was between ~93-102% of the labeled amount. The amount of fluoride released after 1 minute of homogenous mixing ranged between 75-107% of the labeled amount. The pH values of the nine dentifrices ranged from 6.5 to 7.7. Charcoal did not significantly contribute to cytotoxicity in L929 cells. The concentrations of each heavy metal (Hg, Cd, As and Pb) present in each of the nine dentifrices were < 1 ppm, indicating trace amounts. The CDs were not significantly more abrasive than the NCDs. The SnF₂ CD had the highest EFU value (644.2 ±131.7 ppm) followed by the NaF CD and the Na₂MFP CD at 492.2± 69.5 ppm and 140.1± 28.1 ppm, respectively.

Clinical significance: Charcoal-containing dentifrices were not found to be significantly more abrasive or cytotoxic than non-charcoal-containing dentifrices. Charcoal and non-charcoal-containing dentifrices were also found to be comparable through experiments determining their fluoride content, pH, enamel fluoride uptake and heavy metals.

Purpose: To evaluate the influence of imaging compression on radiographic diagnosis of periodontal bone loss on smartphones.

Methods: 45 digital periapical radiographs with diverse periodontal bone loss patterns were selected. All radiographs were performed with a CMOS-type sensor and were exported from the acquisition software with two compressions: JPEG with a 10% compression rate and JPEG with a 90% compression rate. Images were shared using the WhatsApp application and three examiners evaluated all radiographs on the smartphone. The examiners' diagnostic agreement was evaluated using the Kappa index. The McNemar and Cochran's Q statistical tests were used to compare the impact of the image compression, examiner, and type of periodontal bone defect on the diagnosis. Statistical analysis was performed using the SPSS software.

Results: Kappa values were greater than 0.7 for all examiners and no statistically significant difference for the periodontal diagnosis, regardless of the image compression, the examiner background, and the type of periodontal bone defect.

Clinical significance: The use of smartphones to analyze and share images has become very common in dentistry. This study shows that images can be shared and analyzed on smartphones without compromising periodontal diagnosis, regardless of their spatial resolution.

Purpose: To evaluate the marginal and internal misfit of fixed partial denture zirconia frameworks developed from conventional impression and intraoral scanning, before and after being subjected to the thermal cycle of the covering ceramic.

Methods: A three-elements fixed partial denture was prepared, molded, and poured with polyurethane. Group CI (n= 7) was impressed by the conventional technique with polyvinyl siloxane material, and the plaster models scanned on the inEosX5 bench scanner. Group DI (n=07) was scanned using the CEREC Bluecam intraoral scanner. The models and images obtained were sent to the laboratory and the frameworks were made using zirconia blocks. After this, they were subjected to the ceramic thermal cycle, simulating the ceramic application. Marginal and internal misfits of the frameworks were measured before (T1) and after (T2) thermal cycle simulation using the replica technique in an optical microscope. Statistical analysis was performed using the mixed effects of linear model tests and comparisons.

Results: There were no statistical differences for axial misfit. Significant differences were found between the groups for occlusal, vertical, horizontal, and absolute misfit, where group CI had higher values than group DI (P< 0.001). At the time, there was a statistical difference only in the absolute misfit, where T1 had lower values than T2. The misfit in group CI was greater than in group DI; however, the average misfit values found are low and considered clinically acceptable.

Clinical significance: Knowing marginal and internal misfit is an important step to consolidating digital impressions in fixed partial dentures, implying a secure use of this technique.

Purpose: To evaluate the surface roughness and color stability of a single-shade composite resin after thermal cycling with different finishing and polishing systems.

Methods: A total of 91 specimens were prepared with standard molds using a single-shade resin composite Omnichroma. The specimens were randomly separated into seven groups: Control (Mylar strip only), grit (600 grit SiC abrasive paper), OneGloss, Clearfil Twist Dia, Sof-Lex Diamond Polishing System, EVE Diacomp Plus Twist, and OptiDisc. The top surface of each specimen was polished per the manufacturers' directions. After initial measurements, 10,000 and 50,000 thermal cycles were performed. After each thermal cycling, the measurements were retaken. A generalized linear model analysis was used to compare the values, and multiple comparisons were performed with the Bonferroni correction.

Results: Different finishing and polishing systems and thermal cycling significantly affected the surface roughness and color change of the single-shade composite resin (P< 0.001). The smoothest surfaces were obtained with the Sof-Lex Diamond Polishing System, while the group polished with Clearfil Twist Dia showed the least color change.

Clinical significance: The surface roughness of the single-shade resin composite exhibited acceptable values for all polishing systems tested. The color change values of the single-shade resin composite were found to be above the acceptable value for all polishing systems, but the two-step spiral polishing systems performed better in terms of color stability.

Purpose: To evaluate the shear bond strength (SBS) of resin composite to dentin contaminated with artificial saliva (AS) containing mucin and amylase using an experimental method controlling the volume of saliva and adhesive in a defined surface area.

Methods: Flat bonding surfaces were prepared on extracted human molars (320 grit surface). Using adhesive tape, a 4.5 mm bonding window was prepared on the dentin surfaces. Groups (n= 12) were prepared using the etch & rinse (ER) or self-etch (SE) modes for Adhese Universal (ADH), Scotchbond Universal Plus (SBU), and Prime & Bond active (PBA) dental adhesives (DA). For the control (C) groups, the adhesives were applied per the manufacturers' instructions with 2.0 µl or 3.0 µl of the adhesive. For the saliva-contaminated groups, 1.0 µl of artificial saliva with mucin was applied in the bonding window either dried or allowed to remain wet before the application of either 2.0 µl or 3.0 µl of the adhesive. After the adhesive film was air dried and light cured using an Ultradent bonding fixture, Spectrum TPH3 was bonded to the prepared surfaces. After water storage for 24 hours at 37°C, the specimens were debonded and shear bond strength (SBS) was calculated (MPa). A Kruskal-Wallis test with Bonferroni correction was used to determine group differences (P< 0.05). Scanning electron microscopy (SEM) was performed to visualize the interfacial surfaces prepared using an ion-etching technique.

Results: Mean SBS for the three adhesives were similar in both ER and SE modes to uncontaminated dentin surfaces for all the control groups. For dentin contaminated with dried or wet saliva, both the surface condition and the adhesive system were significant factors at a confidence level of 95%. For the dried saliva test groups, ADH and PBA with 3.0 µl of adhesive generated similar SBS values to controls while SBU generated lower values. Lower values were generated when using 2.0 µl of adhesive for the three adhesives in SE and ER modes except for PBA in the ER mode. Using wet saliva and 3.0 µl of adhesive ADH and SBU generated lower SBS values while PBA generated similar values to controls. Under SEM, morphology at the adhesive dentin interfaces was similar among the adhesives to uncontaminated dentin but notable differences were observed for SBU and ADH for both wet and dried saliva-contaminated surfaces.

Clinical significance: Salivary contamination differentially affects shear bond strength and the morphology of the bonded interface of universal adhesives to dentin. These differences are specific to the adhesive tested and are influenced by using the etch and rinse or self-etch strategies and the volume of adhesive used. When concerned about salivary contamination clinically, maximizing the volume of adhesive on the substrate may help mitigate the deleterious effects of saliva contamination.

Purpose: To evaluate color change in ceramic veneers luted to enamel with light-cured, dual-cured resin luting agents, or heated resin composites, as well as to evaluate microhardness and diametral tensile strength of these luting agents.

Methods: For color analysis, 0.5 mm-thick leucite-reinforced glass ceramic veneers (IPS Empress CAD) were cemented onto 40 bovine dental blocks (n= 10) using RelyX Ultimate (RU) or RelyX Veneer (RV) resin-based luting agents, or Gradia Direct (GD) and Palfique Lx5 (P) heated resin composites. After luting, the specimens were subjected to thermocycling (10,000 cycles). Color analysis was performed before and after thermocycling (L*, a*, b*, ΔEab, ΔE₀₀). For the microhardness (Knoop) and diametral tensile strength tests, specimens (Ø 6 x 2 mm) were made (RU, RV, GD, and P). The specimens were subdivided into eight groups (n=10) and light-cured through different ceramic sheets (thicknesses of 0.5 mm or 1.5 mm). Knoop microhardness was performed on the top surface in a microhardness tester, and diametral tensile strength on a universal testing machine. Data were submitted to statistical analysis, using two-way ANOVA, Tukey, and Kruskal-Wallis tests (α= 0.05).

Results: For the general color alteration, there was no statistically significant difference between the luting materials (ΔEab, P= 0.57; ΔE₀₀, P= 0.50). There was no interaction between luting agent and thermocycling, for L* (P= 0.87), a* (P= 0.97) and b* (P= 0.95) values. Thermocycling significantly affected only the L* values (P= 0.047), which increased after the cycles. For microhardness, there was a statistically significant difference considering luting agents and ceramic thickness (P< 0.001). GD heated resin composite presented significantly lower microhardness values than all other materials, at both ceramic thicknesses. At a thickness of 1.5 mm, RU cement had higher microhardness values than RV and P materials. Diametral tensile strength was significantly influenced by luting agent (P= 0.01), but not by ceramic thickness (P= 0.55). Diametral tensile strength of GD resin composite was higher than that of the RU, but neither of these two materials differed from RV and P.

Clinical significance: Heated resin composite, used as luting agents, showed similar color stability to light-cured and dual-cure resin cements, however its microhardness was affected by ceramic thickness.

Purpose: To investigate the influence of temporary cementation and subsequent bonding on the durability during in-vitro aging-simulation and fracture force of resin-based composite crowns.

Methods: Identical molar crowns (n=48, n=8 per group) were milled from resin-based composites and temporarily cemented and finally bonded to human molars. To simulate temporary application, crowns were cemented either with zinc-oxide-eugenol-cement (Tempbond) or with eugenol free zinc-oxide-cement (Tempbond NE). For a first simulation of a long-term provisional clinical application, thermal cycling, and mechanical loading (TCML 2 x 600 x 5°C-55°C, 2 minutes each cycle, distilled water, 240,000 cycles at 50N) was performed. After TCML all crowns were removed, cleaned, and luted either by using etch-and-rinse technique (Vococid, Futurabond U, Bifix QM) or a self-adhesive (Bifix SE) cementation system. A second thermal cycling and mechanical loading (TCML 2 x3,000 x 5°C/55°C, 2 minutes each cycle, distilled water, 1.2 x 10⁶ at 50N) was accomplished to simulate 5 years of clinical application. To assess the survival of the crowns, the failure rates during TCML were documented. As controls, crowns were included without prior provisional cementation. After TCML all crowns were loaded to failure. Failure was categorized as fracture of the crown and partial loosening of the crown.

Results: All crowns survived both TCML procedures without any failures. The fracture values after TCML varied between 3,538.0 ± 1,041.2 N and 4,612.0 ± 801.5 N without significant (P= 0.146) differences between the individual groups. No correlation was found between fracture force and type of provisional cementation (zinc-oxide-eugenol vs. zinc-oxide: Pearson: -0.063/P= 0.672) or type of bonding (adhesive vs. self-adhesive: Pearson: -0.151/ P= 0.307). No different failure pattern was observed between the tested systems.

Clinical significance: Regardless of the type of temporary cementation, there was no effect on the in-vitro performance or strength of the final permanently bonded crowns. Resin-based crowns might be bonded with adhesive or self-adhesive systems even after previous temporary cementation.