Effect of experimental moringa and propolis toothpastes on surface microhardness of simulated hypersensitive dentin

Objective Objective was to investigate the effect of NovaMin toothpaste and two experimental toothpastes on surface microhardness of hypersensitive dentin. Methods Eighty specimens were prepared and divided randomly into eight groups (n = 10/group) according to the tested toothpastes (NovaMin, moringa and propolis toothpastes) and the acidic challenge (with or without 6% citric acid challenge). Enamel surfaces were removed, and the dentin surfaces were exposed on which the three tested toothpastes were brushed twice a day for 1 week using an electric toothbrush, then a 4-d citric acid cycling model with pH 5 was performed. The prepared specimens were stored in artificial saliva until the microhardness test was performed. Statistical analysis was done using One-way ANOVA followed by Tukey post hoc test. Results NovaMin-containing toothpaste showed an increased dentin surface microhardness following a week of twice daily brushing compared to other groups. However, NovaMin-containing toothpaste showed the highest microhardness values following pH cycling with citric acid of pH 5 compared to other tested groups. Conclusions NovaMin-containing toothpaste showed a partial recovery of dentin microhardness at pH 5 during the acidic challenge. Moreover, propolis- and moringa-containing toothpastes had an insignificant effect on dentin surface microhardness with and without citric acid challenge.

Novel Pastes Containing Polymeric Nanoparticles for Dentin Hypersensitivity Treatment: An In Vitro Study

Tubule occlusion and remineralization are considered the two main goals of dentin hypersensitivity treatment. The objective is to assess the ability of dentifrices containing zinc-doped polymeric nanoparticles (NPs) to enduringly occlude the dentinal tubules, reinforcing dentin’s mechanical properties. Fifteen dentin surfaces were acid-treated for dentinal tubule exposure and brushed with (1) distilled water, or with experimental pastes containing (2) 1% of zinc-doped NPs, (3) 5% of zinc-doped NPs, (4) 10% of zinc-doped NPs or (5) Sensodyne®. Topographical and nanomechanical analyses were performed on treated dentin surfaces and after a citric acid challenge. ANOVA and Student–Newman–Keuls tests were used (p < 0.05). The main results indicate that all pastes produced tubule occlusion (100%) and reinforced mechanical properties of intertubular dentin (complex modulus was above 75 GPa). After the citric acid challenge, only those pastes containing zinc-doped NPs were able to maintain tubular occlusion, as specimens treated with Sensodyne® have around 30% of tubules opened. Mechanical properties were maintained for dentin treated with Zn-doped NPs, but in the case of specimens treated with Sensodyne®, complex modulus values were reduced below 50 GPa. It may be concluded that zinc-doped NPs at the lowest tested concentration produced acid-resistant tubular occlusion and increased the mechanical properties of dentin.

An Observational Study to Evaluate the Association between Intestinal Permeability, Leaky Gut Related Markers, and Metabolic Health in Healthy Adults

We explored whether metabolic health is linked to intestinal permeability, using a multi-sugar (MS) permeability test, and whether intestinal permeability is correlated with the leaky gut-related markers (LGM) zonulin, LBP, and sCD14. Metabolically healthy (n = 15) and unhealthy subjects (n = 15) were recruited based on waist circumference, fasting glucose, and high-density lipoprotein cholesterol levels. Participants underwent an MS permeability test that assessed site-specific permeabilities of the gastroduodenum and small and large intestines. The test was performed with/without an acetylsalicylic acid challenge to measure and correlate the gut permeability, LGM, and metabolic health. At baseline, metabolic health showed no correlation with gut permeability. Significant correlations were found between the metabolic health parameters and LGM. In the acetylsalicylic acid challenged MS permeability test, low-density lipoprotein cholesterol was correlated with the sucralose/erythritol ratio, reflecting the whole intestinal permeability. Correlations between most metabolic health parameters and LGM during the acetylsalicylic acid challenge were less pronounced than at baseline. In both MS permeability tests, no significant correlations were found between LGM (plasma and serum) and gut permeability. Thus, correlations between LGM and metabolic health might not be linked with paracellular gut permeability. Transcellular translocation and/or lipoprotein-related transportation is a more likely mechanism underlying the association between LGM and metabolic health.

Liver-specific Deletion Of Small Heterodimer Partner Alters Enterohepatic Bile Acid Levels And Promotes Bile Acid-Mediated Proliferation In Male Mice

ABSTRACTSmall heterodimer partner (Shp) regulates several metabolic processes, including bile acid levels, but lacks the conserved DNA binding domain. Phylogenetic analysis revealed conserved genetic evolution of Shp, Fxr, Cyp7a1 and Cyp27a1, underscoring the importance of these molecules in maintaining bile acid homeostasis. Shp, although primarily studied as a downstream target of Farnesoid X Receptor (Fxr), has a distinct hepatic role that is poorly understood. Here we report that liver-specific Shp knockout (LShpKO) mice have impaired negative feedback of Cyp7a1 and Cyp8b1 upon bile acid challenge and demonstrate that a single copy of the Shp gene is sufficient to maintain this response. LShpKO mice also exhibit elevated total bile acid pool with higher bile acid fraction in the intestine mimicking the 1% cholic acid (CA) fed control mice. Agonistic activation of Fxr (GW4064) in the LShpKO did not alter the elevated basal expression of Cyp8b1 but lowered Cyp7a1 expression. We found that deletion of Shp led to an enrichment of distinct motifs and pathways associated with circadian rhythm, amino and carboxylic acid metabolism, copper ion transport, and DNA synthesis. LShpKO livers displayed a higher basal proliferation that was exacerbated specifically with bile acid challenge but not with another liver mitogen, TCPOBOP (TC). Overall, our data indicate that hepatic SHP uniquely regulates certain proliferative and metabolic cues.

Acid Challenge on Push-Out Bond Strength of Three Different Tricalcium Silicate Cements: An In-vitro Study

Aim: To evaluate the impact of environmental pH on intra-radicular dentin push-out bond strengths of MTA, MTA HP, and Biodentine. Materials and Methodology: Freshly extracted human mandibular single-rooted premolars or maxillary anterior incisors that were either intact or contained only small carious lesions were selected.120 mid root dentins is horizontally divided into 1.0 mm thick slices and divided into 3 MTA, MTA HP, BIODENTINE groups. The compressive load is applied at a speed of 0.5 mm/min by exerting a downward pressure on the outer surface of MTA using a 1.00 mm diameter cylindrical stainless-steel plunger. Maximum load to MTA was reported in newtons at the time of dislodgement and converted to megapascals. The 1-way analysis of variance test was used to compare the push-out bond strength of the groups with the same storage time (4 or 34 days), followed by the pair-wise comparison of the Tukey post hoc test. The Student's t-test was used to evaluate 3-group means. At P = .005, the degree of significance was set. Thus the clinical importance of the present study states that considering several factors like microhardness, composition by products, particle sizes and the environmental pH plays a critical role in selection of root end filling material. Results: There was significant difference between groups (P = .001) after 4 days of PBS and Acid condition, where Bio dentine had significantly the highest bond strength. Conclusion: The strength of MTA HP, BIODENTINE, MTA materials at dentine interface increases over 30 days in the storage of PBS solution at pH 7.4, after an initial acid challenge by acetic acid of pH 5.4, which decreases initial bond strength.

In Vitro Evaluation of Desensitizing Agents Containing Bioactive Scaffolds of Nanofibers on Dentin Remineralization

This study evaluated the effect of the incorporation of bioactive nanofibers in desensitizing agents on dentin permeability. Sixty disks of dentin were randomly distributed in four groups (n = 15). Distribution was based on the desensitizing agents, fluoride varnish and self-etching adhesive, and the presence of nanofibers: C (self-etching adhesive Clearfil SE Bond), CN (Clearfil SE Bond with 1% nanofiber), D (Duraphat varnish), and DN (Duraphat varnish with 1% nanofiber). Dentin permeability was determined using hydraulic conductivity. For a qualitative analysis, confocal laser microscopy and scanning electron microscopy were performed. The C group showed the lowest hydraulic conductance (Lp%) (89.33), while the DN group showed the highest Lp% (116.06). No statistical significance was observed in the Lp% values in all groups after the treatment and 6% citric acid challenge (p > 0.239). In the images, the CN group presented a higher superficial and intratubular deposition. In addition, this group presented a more homogeneous dentin surface and wide occlusion of dentinal tubules than the other treatments. Despite there being no statistical differences among the treatments employed, the images showed that the CN group presented a higher surface and intratubular deposition compared to the other treatments, even after the acid challenge.

Assessment of the acid resistance behaviour of dentin tubules occluded by different desensitizers

Aim: To evaluate the efficacy of in-office and home-based products in the prevention of dentinal hypersensitivity on dentin discs. Methodology: Ninety-six dentin disc samples of 1 mm were divided equally into six groups as follows: TeethmateTM, Smartprotect®, novamin®, Arginine calcium carbonate, potassium oxalate with rinse and saline (control). After acid etching, test agents were applied, and eight samples in each group were subjected to citric acid. SEM examination (3000x) and statistical analysis were carried out. Results: Before citric acid challenge, novamin® and teethmate had superiority when compared to others (p<0.001), but there was no a statistical difference between novamin® and teethmate. After citric acid challenge, teethmate and smartprotect showed resistance on occluded tubules. The decreasing in the level of occluded tubules in novamin® group was statistically significant (p<0.05). In-office products including teethmate and smartprotect were found more successful compared to home-based products. Smartprotect resisted against to citric acid (0.506). Conclusion: Novamin® showed a successful occlusion in all tubules before acid challenge whereas; it was the most unsuccessful group after acid challenge when compared to other agents. In-office agents were found to be more successful in reducing dentine permeability than home-care products. In-office agents showed more resistance to acid attacks. Further studies are needed to assess the efficacy of desensitizer agents. How to cite this article: Karayürek F, Arpağ OF. Assessment of the acid resistance behaviour of dentin tubules occluded by different desensitizers. Int Dent Res 2020;10(3):80-9. https://doi.org/10.5577/intdentres.2020.vol10.no3.3 Linguistic Revision: The English in this manuscript has been checked by at least two professional editors, both native speakers of English.

Effect of ageing media on shear bond strength of metal orthodontic brackets bonded with different adhesive systems (A comparative in-vitro study)

Background: The aim of this study was to evaluate the shear bond strength (SBS) and adhesive remnant index (ARI) of different orthodontic adhesive systems after exposure to aging media (water storage and acid challenge). Materials and methods: Eighty human upper premolar teeth were extracted for orthodontic purposes and randomly divided into two groups (40 teeth each): the first group in which the bonded teeth were stored in distilled water for 30 days at 37°C, and the second group in which the bonded teeth were subjected to acid challenge. Each group was further subdivided into four subgroups (10 teeth each) according to the type of adhesive system that would be bonded to metal brackets: either non-fluoride releasing adhesive (NFRA), fluoride releasing adhesive (FRA), Fluoride releasing bond with self-etching primer (FRBSP), or powder and liquid orthodontic fluoride releasing adhesive (PLFRA). After 30 days of water storage and acid challenge ageing procedures, the SBS was determined using Instron testing machine with a crosshead speed of 1 mm/min. The ARI was assessed using a stereomicroscope with 10 X magnification. Result: The SBS testing revealed significant differences (p< 0.05) among the four tested adhesive systems in water storage and acid challenge groups using ANOVA F-test. In both groups, the NFRA subgroup exhibited the highest mean SBS value, followed by FRASP, then FRA subgroups, while the PLFRA subgroup had the lowest value of mean SBS. The independent t-test showed non-significant differences in mean SBS values between water storage and acid challenge groups. In respect to the ARI analysis, the Chi-square test showed significant differences among the tested adhesive systems. Conclusion: The shear bond strength of the fluoride releasing adhesive system was less than that of the non-fluoride releasing adhesive system, but still above the clinically acceptable range.