Antibacterial Effect of Ozone on Cariogenic Bacteria and Its Potential Prejudicial Effect on Dentin Bond Strength-An In Vitro Study.

Ozone is increasingly utilized in dental caries treatment due to its antibacterial properties. In a context of limited studies and no consensus on protocols, this research aims to assess ozone's antibacterial efficacy on cariogenic bacteria and its potential adverse impact on dentin bond strength. Streptococcus mutans, Streptococcus sobrinus, Lactobacillus casei, and Actinomyces naeslundii suspensions were exposed to 40 µg/mL of ozone gas and 60 µg/mL of ozonated water (80 s) via a medical ozone generator. Negative and positive control groups (chlorhexidine 2%) were included, and UFC/mL counts were recorded. To examine microtensile bond strength (µTBS), 20 human molars were divided into four groups, and class I cavities were created. After ozone application, samples were restored using an etch-and-rinse and resin composite, then sectioned for testing. The SPSS v. 28 program was used with a significance level of 5%. The µTBS results were evaluated using one-way ANOVA, Tukey HSD, and Games-Howell. Bacterial counts reduced from 106 to 101, but dentin µTBS was significantly impacted by ozone (ANOVA, p < 0.001). Despite ozone's attractive antibacterial activity, this study emphasizes its detrimental effect on dentin adhesion, cautioning against its use before restorative treatments.

Comparison of Cytokine RANTES/CCL5 Inflammation in Apical Periodontitis and in Jawbone Cavitations - Retrospective Clinical Study.

Background: Apical periodontitis (AP) is one of the most common endodontic diseases associated with osteo destructive cytokine production. The literature also reports cytokine studies in fatty degenerative osteonecrotic bone marrow defects (BMDJ/FDOJ) independent of AP. Objective: We compare the RANTES/CCL5 (R/C) chemokine production between AP and BMDJ/FDOJ. For both pathologies, the R/C expression was also compared to radiographic diagnosis in 2D-OPG, 3D-CBCT/DVT. Material and Methods: Postoperative samples were collected and divided in three different groups: HB (healthy jawbone) (n=19), APs (n=19), and BMDJ/FDOJ (n=7). The R/C expression was evaluated using multiplex analysis. In addition, two clinical cases from AP and BMDJ/FDOJ groups were randomly selected and radiographic diagnosis in 2D-OPG and 3D-CBCT/DVT was compared to TAU measurements and R/C expression in AP and in BMDJ/FDOJ. Results: BMDJ/FDOJ showed the highest R/C expression (2498.71 pg/mL), followed by AP (841.85 pg/mL) and HB (149.85 pg/mL) (AP vs BMDJ/FDOJ = p=0.01; AP vs HB = p=<0.01; BMDJ/FDOJ vs HB = p=<0.01). In both clinical cases, the radiographic findings depict the AP areas in OPG and CBCT/DVT, in contrast to the BMDJ/FDOJ areas. Conversely, the systemic immunological R/C expressions are threefold and fivefold excessive in both cases. Discussion: AP is recognized as a pathology requiring treatment, while the pathogenesis of BMDJ/FDOJ is controversially discussed in the literature, despite stronger potential systemic immunological effects (breast cancer (case 1) and multiple sclerosis (case 2)). The inadequate radiographic representation of reduced bone density in BMDJ/FDOJ areas could be a reason for this contradiction. Conclusion: The data presented provide the first quantitative analysis of R/C expression in AP and BMDJ/FDOJ. BMDJ/FDOJ showed high R/C expression than AP, besides the diagnostic through radiographs being extremely poor. To cover this imprecision, a radiation-free TAU device is available.

Comparative Assessment of Different Pre-Treatment Bonding Strategies to Improve the Adhesion of Self-Adhesive Composites to Dentin.

The aim of this study is to compare the adhesive interface formed in dentin, using self-adhesive composites applied with different bonding strategies, by testing the microtensile bond strength (µTBS) and ultramorphology through the use of light microscopy. Permanent, sound human molars were randomly allocated to six experimental groups. The groups included a negative control group, where only etching was performed via EtchOnly; a positive control group where an adhesive was applied, OptiBondFL (OBFL); and an experimental group where a primer was applied using a co-curing strategy together with a composite (Primer_CoCuring). The samples were sectioned into microspecimens for µTBS (n = 8) and into 1-mm thick slabs for light microscopy using Masson's trichrome staining protocol (n = 3). The statistical analysis included a two-way ANOVA for µTBS data and Tukey's HSD was used as a post-hoc test (significance level of 5%; SPSS v. 26.0). The results of the µTBS revealed that the self-adhesive composite (F = 6.0, p < 0.018) and the bonding strategy (F = 444.1, p < 0.001) significantly affected the bond strength to dentin. However, their interactions were not significant (F = 1.2, p = 0.29). Etching dentin with no additional treatment revealed the lowest µTBS (VF_EtchOnly = 2.4 ± 0.8 MPa; CC_EtchOnly = 2.0 ± 0.4 MPa), which was significantly different from using a primer (VF_CoCu = 8.8 ± 0.8 MPa; CC_CoCu = 6.3 ± 1.0 MPa) or using the full adhesive (VF_OptiBondFL = 22.4 ± 0.3 MPa; CC_OptibondFL = 21.2 ± 0.4 MPa). Microscopy images revealed that the experimental Primer_CoCuring was the only group with no collagen fibers exposed to the dentin−composite interface. Overall, the use of a primer, within the limitations of this study, increased the bonding of the self-adhesive composite and provided sufficient infiltration of the collagen based on light-microscopic imaging.

Improving Properties of an Experimental Universal Adhesive by Adding a Multifunctional Dendrimer (G-IEMA): Bond Strength and Nanoleakage Evaluation.

A vast number of adhesive formulations exist currently. However, available adhesives still have several drawbacks such as increased hydrophilicity, polymerization deficiency, potential cytotoxicity and limited monomer interdiffusion within dentin. To improve material properties, a Bisphenol A-free adhesive containing a novel dendrimer G(2)-isocyanatoethyl methacrylate (G-IEMA) in replacement of Bis-GMA was made and tested. Sound human molars were sectioned to expose mid-coronal dentin, which was bonded using four adhesives­Futurabond, Scotchbond Universal and experimentals EM1 and EM2. The experimental adhesive EM2 contained G-IEMA, while EM1 had Bis-GMA. Groups were further allocated to two different adhesive strategies: etch-and-rinse (20 s etching) or self-etch. Immediate (24 h) microtensile bond strength to dentin (n = 5) was tested using a universal testing machine (1 mm/min, 5 kN; Shimadzu AGS-X Autograph, Tokyo, Japan), while the ultrastructure of the interface (n = 2) was assessed using scanning electron microscopy-energy dispersive spectroscopy (SEM-EDS). Nanoleakage expression was evaluated using silver nitrate penetration and posterior SEM-EDS analysis (n = 3). Linear mixed models/Generalized models were used for inferential statistics (5% significance level). Bond strength results did not depend on the adhesive choice, although differences were found between strategies (p < 0.001). Regarding nanoleakage, when applied in an etch-and-rinse mode, experimental adhesives scored lower nanoleakage means than Futurabond and Scotchbond Universal. The novel adhesive shows interesting interfacial properties, with favorable nanoleakage results and a bond strength to dentin that matches current commercial adhesives.

Dentin Bonding and SEM Analysis of a New Experimental Universal Adhesive System Containing a Dendrimer.

Due to their polymerization characteristics, hyper-branched dendrimers have lately shown to be promising candidates for use in dental materials. In this study, a new dental adhesive system was prepared, using a dendrimer derived from 2-isocyanatoethyl methacrylate (G-IEMA), and its adhesive properties were investigated. The exposed dentin was treated with four universal adhesives (UAs): SBU (Scotchbond Universal™), FUT (Futurabond M+™), AE1 (experimental adhesive with Bis-GMA) and AE2 (experimental adhesive with G-IEMA), using Etch & Rinse (ER) or Self Etch (SE) protocols. Composite build-ups were prepared and stored for 24 h at 37 °C in distilled water. Composite/dentin beams were prepared with cross-sectional areas of 1 ± 0.3 mm2 and µTBS (Micro-tensile bond strength) test was performed at 0.5 mm/min. Failures modes were evaluated by stereomicroscopy, and bonding interfaces were observed by scanning electron microscopy (SEM). Statistical analysis of µTBS data was performed using General Linear (GLM) and Linear Mixed Models (LMM). The effect of adhesive type on µTBS was significant (p = 0.010), with AE1 presenting significantly higher µTBS than SBU (p = 0.019). No other differences between adhesives were observed. ER showed significantly better results than SE (p = 0.019), and no significant interactions between the adhesives and protocols were determined. Results obtained so far pinpoint the emergence of a new paradigm in the dental materials field, as G-IEMA can be used successfully as an alternative to Bis-GMA.