Occlusion, acid resistance, and elemental characterization of dentin treated with desensitizing agents.

Animal teeth are a common model in studies on dentin adhesive materials. The aim of this study was to compare microstructural parameters (density and diameter of dentinal tubules (DT), peritubular dentin (PTD) thickness, PTD and intertubular dentin (ITD) surface area) and chemical characteristics of canine, porcine, equine, and human root dentin. The middle layers of dentin were harvested just below a cemento-enamel junction from incisors and investigated by means of scanning electron microscopy (SEM) and energy dispersive X-ray spectroscopy (EDXS). SEM evaluation of the specimens revealed, that porcine dentin shared most similarities with human dentin. When comparing the density of DTs, canine dentin was also found to be similar to human dentin. Elemental composition of the root dentin did not differ significantly in porcine, equine and human dentin, but in canine dentin higher magnesium value in PTD compared to ITD was found. It is known that microstructural and chemical characteristics affect the strength of the adhesive bonds created among restorative materials and dentin. According to the results of this study, porcine dentin seems to be the most appropriate model to study dental materials to be used in human restorative dentistry.

The Study of a Contaminated Colonoscope

In vitro dentine tubule occlusion by a novel toothpaste containing calcium silicate and sodium phosphate

This study aimed to evaluate the inhibitory effect of experimental pastes containing surface pre-reacted glass ionomer (S-PRG) fillers on enamel demineralization. Bovine blocks were treated twice a day for 4 days by 7 groups; experimental pastes containing 0-30 wt% S-PRG filler (S00, S01, S05, S10, and S30), deionized water (DW) as negative control, and NaF paste (MP) as positive control. The surfaces were demineralized by acetic acid for 3 days. Mineral loss (ML) was calculated by micro-computed X-ray tomography. The treated surface was finally investigated with scanning electron microscope (SEM) and micro-focused particle induced X-ray emission (micro-PIXE). S05, S10 and S30 demonstrated significantly lower ML than S00, S01 and DW (p<0.05). S10 showed the greatest inhibitory effect, which was significantly greater than MP. The S-PRG filler containing experimental pastes demonstrated a potential to inhibit enamel demineralization. Sr ion incorporation was confirmed on the enamel surface with the experimental pastes.

This study evaluated the ability of resin composites containing S-PRG fillers to modulate the pH of the surrounding medium, as well as their surface roughness and gloss following an erosive/abrasive challenge. Resin disks (⌀4mm × 2mm) (n=15) were prepared using Filtek Z350 XT (control), Beautifil II, Beautifil II Enamel, and Beautifil II LS (the latter three containing S-PRG fillers). To assess buffering capacity, disks (n=5) were immersed in a demineralizing solution, and pH was measured at baseline and after 1, 3, 7, 14, and 21 days. Separate specimens (n=10) underwent daily erosion cycles using 0.3% citric acid, combined with abrasion via toothbrushing, conducted over a 5-day period to simulate an acidic diet and twice-daily oral hygiene. Surface roughness (Ra) and gloss (GU) were assessed at baseline, after polishing, and following the challenge; surface topography was analyzed by a scanning electron microscope (SEM). Data were analyzed using a generalized linear mixed model for repeated measures over time, in addition to Tukey-Kramer, Kruskal-Wallis, Dunn, Friedman, and Nemenyi tests (α=0.05). All materials showed a significant increase in the pH of the surrounding medium over time (p<0.05). After 24 hours, Beautifil II exhibited a significantly higher pH than the others (p<0.05). Filtek Z350 XT demonstrated lower surface roughness than the other materials after the erosive/abrasive challenge (p<0.0001). Following the challenge, Beautifil II and Beautifil II Enamel presented higher gloss values (p<0.05). Resin composites containing S-PRG fillers slightly increased the pH of the surrounding medium over time. Surface roughness increased after the erosive/abrasive challenge, although the gloss of the S-PRG-containing composites also improved.

Improving laboratory practice: looking at fetal hemoglobin histograms.

The purpose of this study was to compare the effect of a self-etching primer and a non-rinse conditioner with the effect of a conventional adhesive system on the penetration depth in dentin of human teeth, using scanning electronic microscopy (SEM). Fifteen human third molar teeth were sectioned into 2 pieces. All pieces were flattened with grade 600 to 1200 silicon carbide paper and divided into 6 groups: group 1 - Prime & Bond NT (NT), negative control; group 2 - 37% phosphoric acid + Prime & Bond NT (PANT), positive control; group 3 - Non-rinse Conditioner (NRC) + Prime & Bond NT (NRCNT); group 4 - NRC + Prime & Bond 2.1 (NRCPB); group 5 - NRC + Scotchbond MP (NRCSB); group 6 - Prompt L-Pop (PLP). All teeth were covered with Dyract AP. The tooth fragments were decalcified, and its resin replicas were evaluated by SEM by three previously standardized examiners. The penetration was scored from 0 (no penetration) to 3 (maximum penetration). The Kruskal-Wallis and Mann-Whitney U tests (p<0.05) showed three statistically homogeneous groups: (NT, NRCPB, NRCSB and PLP), (NRCNT) and [PANT]. The authors concluded that the self-etching primer and the non-rinse conditioner provide a lower penetration depth in human tooth dentin than the conventional adhesive system.

Objectives To ensure that the marketed product is irritant-free, extensive premarket clinical testing of cosmetic products is necessary. Therefore, the present study evaluated the skin irritation reactions of the test product Venusia Max Cream-Paraben-free using a patch test. Material and methods This single group, blinded, controlled trial was conducted to compare our test product with negative saline and positive SLS control in healthy human subjects aged between 18 and 53 years (mean age of 30.93 years) having Fitzpatrick skin phototype classification III-V. During an initial phase, a patch dipped in test product, negative and positive control were applied under occlusion to the upper arm of participants and removed after 24 hours. Clinical evaluation of skin reactions (erythema, edema, dryness, and scaling wrinkling) in the area of the test product, negative and positive control after 24 hours of patch removal and then were scored based on the Draize scale. Results A total of 30 subjects were initiated and completed the study. Scoring for skin irritation (erythema/dryness/wrinkles/edema) of the subjects were evaluated based on Draize’s scale between test product, positive, and negative control. The combined mean score, i.e., of erythema/dryness/wrinkles, and edema was 0.00 in test product and negative control whereas 2.60 in the positive control. No adverse events or intolerances were reported due to the test product. Conclusion Venusia Max Cream-Paraben-free was dermatologically tested and found to be nonirritant.

Titanium dioxide-doped phosphate glass (TDPG) is silica-free with enhanced chemical stability and ion release properties that could help in dentin remineralization. There is no evidence, however, regarding whether diode laser irradiation can enhance the clinical performance of TDPG paste in this regard. This article aims to evaluate the in vitro effectiveness of the combined use of TDPG paste and diode laser in occluding dentinal tubules, promoting dentin remineralization, and resisting acid challenge in comparison to a commercially available fluoride-containing NuPro prophy paste.This article aims to evaluate the in vitro effectiveness of the combined use of TDPG paste and diode laser in occluding dentinal tubules, promoting dentin remineralization, and resisting acid challenge in comparison to a commercially available fluoride-containing NuPro prophy paste.Seventy mid-coronal dentin discs were prepared from extracted human premolar and molar teeth and randomly distributed into seven groups (n = 10): sound dentin (control), etched dentin (negative control), etched dentin + diode laser, TDPG, TDPG + diode laser, NuPro, and NuPro + diode laser. Treatments were applied accordingly, followed by a 6% citric acid challenge to assess acid resistance. Scanning electron microscopy (SEM) and Raman spectroscopy (RS) were used to evaluate dentinal tubule occlusion and quantify mineral content [phosphate (960 cm-1) and carbonate (1,070 cm-1)] before and after the acid challenge, respectively.SEM analysis showed incomplete tubules' occlusion with TDPG and a more uniform surface coverage with NuPro. Laser irradiation improved surface sealing for both materials. After the acidic challenge, NuPro + laser demonstrated better surface integrity, while TDPG + laser showed moderate resistance. RS revealed a significant reduction in the intensity of the phosphate peak after acid exposure in the NuPro groups, particularly with laser (45.8 and 48.9%, respectively), despite the initial high intensity in comparison to a reduction of 1.8% in the TDPG + laser group. TDPG-treated groups demonstrated increased phosphate and carbonate intensities post-acid challenge. Carbonate intensity followed similar trends, confirming greater acid resistance of TDPG formulations compared with NuPro.TDPG paste demonstrated a more chemically stable remineralization process, while NuPro prophy paste achieved better surface integrity after acidic challenge when used with a diode laser, but laser-induced damage in the form of microcracks was evident. The use of diode lasers may enhance the interaction and penetration of desensitizing agents, although compatibility with material composition must be improved for long-term performance.For immediate symptomatic relief of dentin hypersensitivity, a dual strategy using NuPro + laser is indicated. However, to achieve a sustained mineral reinforcement, the combined use of TDPG-based therapies with laser is recommended.

Evidence of Misclassification of Drug-Event Associations Classified as Gold Standard 'Negative Controls' by the Observational Medical Outcomes Partnership (OMOP).

PurposeTo investigate the impact of common dental hygiene practices, including brushing with fluoridated toothpaste, on titanium implant surfaces with varying degrees of roughness, both in the presence and absence of citric acid.MethodsTitanium (Ti) disks with varying surface roughness (smooth and moderately rough, n = 80) were divided into two groups. Different treatments were applied to each group: control (no treatment, SC, RC), citric acid exposure (S1, R1), citric acid exposure followed by brushing (S2, R2), and citric acid exposure followed by brushing with fluoridated toothpaste (S3, R3). Surface roughness (Ra) was measured using a stylus profilometer and scanning electron microscopy (SEM) was used to examine surface morphology and potential damage. ANOVA associated with the Tukey’s tests were used to compare Ra between the groups.ResultsSmooth Ti surfaces exhibited minimal changes in roughness following various treatments, including citric acid exposure, brushing, and fluoride treatment, with % of change in Ra ranging from 0.43 to 7.1% compared to the control. However, SEM analysis revealed surface alterations such as chipping and scratching. In contrast, rough Ti surfaces showed significant increases in roughness after treatments, with the combination of citric acid and brushing (R1 and R2) causing the most pronounced effects with a 48.8% change in Ra compared to the control. Fluoride treatment may have mitigated these effects to some extent.ConclusionsThe common dental hygiene practices, such as brushing with fluoridated toothpaste and exposure to acidic substances, can significantly impact the surface topography of Ti implants, particularly those with rough surfaces.

Effect of Relaxin on Fertility Parameters of Frozen-Thawed Buffalo (Bubalus bubalis) Sperm.

BackgroundDentin hypersensitivity is a short, severe pain with fast onset. Therapy aims to either prevent or decrease neural transmission or physically occlude the dentinal tubules. This study aimed to evaluate the effectiveness of commercial desensitizing dentifrice by means of an ex vivo method.Material and MethodsSamples (n=8 lower human premolars for each group) were randomly allocated into: G1- brushing with Colgate®Sensitive Pro-Relief; G2- brushing with Sensodyne®Rapid Relief; G3- brushing with Sensodyne®Repair & Protect; and G4- brushing with Colgate®Maximum Cavity Protection. The test bodies were submitted to simulated toothbrushing and dentifrices were analyzed regarding their hydrodynamic size, polydispersity index (PI) and zeta potential. Specimens were evaluated using: scanning electron microscopy (SEM); spectroscopy energy dispersive X-ray (EDS); and profilometry. A qualitative analysis of the photomicrographs and topographies was performed.ResultsThe dentifrices showed statistical similar physical and chemical characteristics. They also demonstrated obliteration of dentinal tubules when micrographs were observed. Regarding the chemical elements present in the dentin samples, there was a statistically significant difference between the control and experimental surfaces in the four groups.ConclusionsJoint data analysis shows that the desensitizing dentifrice showed better results with regards to the obliteration of dentinal tubules compared to positive and negative controls. Key words:Dentin hypersensitivity, dentin desensitizing agents, toothpastes.

Multiple sclerosis (MS) results from the destruction of myelin and focal inflammation. The study aimed to evaluate the effect of hydroalcoholic extract of Urtica dioica on oxidative stress, heat shock proteins, and brain histopathology in multiple sclerosis model. Sixty male C57BL/6 mice were divided into six groups of 10. Groups included positive control, negative control, and treatment groups with U. dioica extract at a dose of 50, 100, 200, and 400 mg/kg for 21 days (three times a week). The MS model was developed by a diet containing 0.2% cuprizone for 6 weeks. A section of brains was evaluated with Luxol Fast Blue staining and the other part evaluated with heat shock protein (HSP) kits 60 and 70, total antioxidant capacity (TAC), and malondialdehyde (MDA). In sections of corpus callosum, the highest amount of myelin was observed in the negative controls, while the use of cuprizone in the positive controls caused the destruction and reduction of myelin. The use of U. dioica extract in therapeutic groups except at a dose of 50 mg/kg could reduce myelin degradation to some extent and lead to remyelination. However, myelin levels in treatment groups were not significantly different from any of the negative and positive controls. Although HSP60 decreased in the treatment groups, there was no significant difference between the positive and negative controls. Treatment with this extract significantly reduced the amount of HSP70 compared with the positive controls. The decreased TAC and increased MDA in positive controls indicated oxidative stress, respectively. Furthermore, the extract led to an increase and decrease of TAC and MDA in the treatment groups, respectively. However, only the MDA level was significantly different from that of the positive controls. Therefore, the antioxidant effects of U. dioica extract could decrease cuprizone‐induced oxidative stress and be effective in improving demyelination.

Kaposi's sarcoma-associated herpesvirus (KSHV) expresses numerous intronless mRNAs that are unable to access splicing-dependent cellular mRNA nuclear export pathways. To circumvent this problem, KSHV encodes the open reading frame 57 (ORF57) protein, which orchestrates the formation of an export-competent virus ribonucleoprotein particle comprising the nuclear export complex hTREX, but not the exon-junction complex (EJC). Interestingly, EJCs stimulate mRNA translation, which raises the intriguing question of how intronless KSHV transcripts are efficiently translated. Herein, we show that ORF57 associates with components of the 48S pre-initiation complex and co-sediments with the 40S ribosomal subunits. Strikingly, we observed a direct interaction between ORF57 and PYM, a cellular protein that enhances translation by recruiting the 48S pre-initiation complex to newly exported mRNAs, through an interaction with the EJC. Moreover, detailed biochemical analysis suggests that ORF57 recruits PYM to intronless KSHV mRNA and PYM then facilitates the association of ORF57 and the cellular translation machinery. We, therefore, propose a model whereby ORF57 interacts directly with PYM to enhance translation of intronless KSHV transcripts.