Canal disinfection using photo-chemically activated micro-bubble emulsion, Emblica officinalis, and Nd: YAP laser on smear layer and push-out bond strength of resin-based root canal sealer to the radicular dentin.

AIMS: Evaluation of the effects of the latest root canal disinfectants i.e., Micro-bubble emulsion (MBE), Neodymium-doped yttrium aluminum perovskite (Nd: YAP), Emblica officinalis (E. officinalis) on the removal of smear layer (SL) and push out bond strength (PBS) of resin-based root canal sealer to the radicular dentin. METHODS: The coronal portion of sixty single-rooted human mandibular premolar teeth was precisely sectioned at the cementoenamel junction. The canals were prepared to utilize ProTaper universal rotary files till F3. All the study specimens were divided into four groups based on the disinfection regime (n = 15) Group 1: 5.25% NaOCl, Group 2: MBE, Group 3: Nd: YAP laser and Group 4: E. officinalis extract. All the canals were then finally irrigated using 17% EDTA solution as a final disinfecting agent. SL removal assessment was performed on five samples from each group using a scanning electron microscope (SEM). Ten samples from each group were then filled with root canal filling material and the roots were sectioned. Push-out test and failure mode analysis were performed using the universal testing machine (UTM) and stereomicroscope respectively. The mean scores of PBS and SL removal were compared using a one-way analysis of variance (ANOVA) and Post Hoc Tukey's HSD test p = 0.05. RESULTS: Group-2 (MBE + EDTA) coronal section (1.50 ± 0.23) exhibited the most effective eradication of SL from the canal space. The apical third of Group-1 (NaOCl+EDTA) (2.68 ± 0.82) samples demonstrated the least effective removal of SL from the radicular canal. The maximum score of PBS of AH plus sealer to the canal dentin was exhibited by the coronal section of Group-2 (MBE + EDTA) (9.55 ± 0.45 MPa) samples. However, the apical third of Group-1 (NaOCl+ EDTA) specimens (5.16 ± 0.32 MPa) demonstrated the minimum EBS. CONCLUSION: MBE+ EDTA displayed better smear layer removal and bond integrity of AH plus sealer to the root canal dentin. Nd: YAP+ EDTA laser and E.officinalis displayed comparable outcomes to that of control NaOCl+ EDTA.

EFFECTS OF PROFESSIONAL ORAL HYGIENE AND TEETH WHITENING ON THE MICROELEMENT COMPOSITION OF ENAMEL.

OBJECTIVE: Aim: The objective of this study is to investigate the impact of professional teeth cleaning and the substances used in modern dentistry for whitening on the microelement composition of tooth enamel. PATIENTS AND METHODS: Materials and Methods: To study the morphology and microelement composition of the enamel, scanning electron microscopy was performed using the MiraLM microscope equipped with a Schottky field emission electron gun from Tescan. RESULTS: Results: A comparative analysis between the areas subjected to mechanical cleaning and those where it was not applied revealed a significant difference in the research results, particularly in carbon, which changed from 25.16±1.04 to 32.02±1.8. An analysis of the enamel's chemical composition before and after whitening revealed a decrease in carbon from 45.91±1.20 to 42.46±1.74. The change in phosphorus content was determined to be from 9.77±0.39 to 9.56±0.75. A decrease in calcium from 15.96±0.64 to 15.21±1.22 and magnesium from 0.07±0.01 to 0.01±0.01 was also observed. CONCLUSION: Conclusions: Professional dental hygiene does not have a direct impact on the microelement composition of enamel, such as the levels of calcium, phosphorus, fluoride, and other microelements. However, it can have an indirect and temporary influence due to the use of abrasive materials that affect dental deposits, pellicle, and the surface layer of enamel. Teeth whitening can affect the microelement composition of enamel, but these changes are mostly temporary and associated with processes of demineralization/ remineralization and oxygenation.

Effect of blood contamination on marginal adaptation of cold ceramic and MTA angelus: a scanning electron microscopic study.

BACKGROUND: This study aimed to assess the effect of blood contamination on marginal adaptation of cold ceramic (CC) and mineral trioxide aggregate (MTA) Angelus using scanning electron microscopy (SEM). METHODS: This in vitro experimental study was conducted on 24 extracted single-rooted human teeth. After cleaning and shaping, the root canals were filled with lateral compaction technique. The apical 3 mm of the roots was cut, and cavities with 3 mm depth were created at the apex. The teeth were randomly assigned to two group (n = 12) for the application of CC and MTA Angelus as retrograde filling materials. CC and MTA Angelus were prepared by mixing the powder with blood, and applied in the cavities. After 24 h, their marginal adaptation to the canal walls was assessed by SEM. Data were statistically analyzed by t-test (alpha = 0.05). RESULTS: The mean marginal gap was 8.98 µm in the CC, and 16.26 µm in the MTA Angelus group; this difference was statistically significant (P < 0.001). CONCLUSIONS: The present in vitro study revealed that following complete blood contamination of powder, CC showed significantly superior marginal adaptation than MTA Angelus as shown by SEM assessment.

Evaluation of the Efficacy of CPP-ACP Remineralizing Mousse in Molar-Incisor Hypomineralized Teeth Using Polarized Raman and Scanning Electron Microscopy-An In Vitro Study.

Remineralization of tooth enamel can be achieved by applying a complex of casein phosphopeptides and amorphous calcium phosphate (CPP-ACP). However, the efficacy and optimization of this agent in molar−incisor hypomineralization (MIH) lacks evidence. The purpose of this study is to evaluate the efficacy of CPP-ACP tooth mousse in remineralizing MIH-affected enamel in an optimized 28-day protocol using polarized Raman microscopy and scanning electron microscopy. The protocol was applied to two types of MIH opacities, white and yellow, and compared against sound enamel specimens before and after treatment. Data was analyzed using a one-way ANOVA and LSD post hoc multiple comparisons test (p < 0.05) for the Raman analysis. Hypomineralized enamel showed an improvement of its structure after CPP-ACP supplementation. In addition, Raman spectroscopy results showed a decrease in the depolarization ratio of the symmetric stretching band of phosphate (p < 0.05 for both groups). In conclusion, there was an improvement in mineral density and organization of the hypomineralized enamel after treatment with CPP-ACP tooth mousse.

Effect of various single file systems on microcrack formation in root canals: Scanning electron microscope study.

BACKGROUND: The aim of this study was to compare dentinal crack formation in root canal walls following 3 single file systems with continuous rotation under a scanning electron microscope (SEM). MATERIALS AND METHODS: In this SEM study, seventy mandibular premolars were randomly divided into 5 groups. 3 experimental groups (n = 20) and 2 control groups (n = 5) as follows: Group I: Neolix NiTi file system, Group II: OneShape systems, Group III: OneCurve file system, positive control: conventional Hand File system, negative control: unprepared. After root canal preparations, the roots were sectioned at 3, 6, and 9 mm from the apex with water irrigation. The sections were inspected in all directions under SEM at × 100 magnification to determine the presence of cracks. The Chi-square test was used to analyze the data. There is a statistically significant difference in the crack formation between the apical third (P = 0.012) and coronal third (P = 0.002) when comparing all the 5 groups. No significant difference is found in the middle third (P = 0.46). P < 0.05 is considered statistically significant. RESULTS: Maximum cracks in the apical third were seen with One Shape file 11 (55%) and in the coronal third with Neolix NiTi 14 (70%). There is a statistically significant difference in the crack formation only in OneCurve when comparing the apical, middle, and coronal third for the individual group (P = 0.042). CONCLUSION: There was a significant difference in crack formation in apical and coronal third. OneCurve caused the least incidence of cracks when compared to other file systems. OneCurve file system can be a choice for canal preparation over Neolix Niti and OneShape.

Agroecological Service Crops Drive Plant Mycorrhization in Organic Horticultural Systems.

Mycorrhizal symbiosis represents a valuable tool for increasing plant nutrient uptake, affecting system biodiversity, ecosystem services and productivity. Introduction of agroecological service crops (ASCs) in cropping systems may determine changes in weed community, that can affect the development of the mycorrhizal mycelial network in the rhizosphere, favoring or depressing the cash crop mycorrhization. Two no-till Mediterranean organic horticultural systems were considered: one located in central Italy, where organic melon was transplanted on four winter-cereals mulches (rye, spelt, barley, wheat), one located in southern Italy (Sicily), where barley (as catch crop) was intercropped in an organic young orange orchard, with the no tilled, unweeded systems taken as controls. Weed "Supporting Arbuscular Mycorrhiza" (SAM) trait, weed density and biodiversity indexes, mycorrhization of coexistent plants in the field, the external mycelial network on roots were analyzed by scanning electron microscopy, crop P uptake, yield and quality were evaluated. We verified that cereals, used as green mulches or intercropped, may drive the weed selection in favor of the SAM species, and promote the mycelial network, thus significantly increasing the mycorrhization, the P uptake, the yield and quality traits of the cash crop. This is a relevant economic factor when introducing sustainable cropping practices and assessing the overall functionality of the agroecosystem.

Morphological and immunohistochemical features of tooth extraction sites in rats treated with alendronate, raloxifene, or strontium ranelate.

OBJECTIVE: The aim of this study was to evaluate morphological and immunohistochemical features of tooth extraction sites in rats subjected to different antiresorptive drugs. MATERIALS AND METHODS: Wistar rats were allocated into 4 groups according to the treatment: (1) alendronate, (2) raloxifene, (3) strontium ranelate, and (4) control. The animals underwent tooth extraction (60th day of treatment) and afterwards were euthanized (90th day of treatment). Tooth extraction sites were analyzed by means of scanning electron microscopy (SEM), hematoxylin-eosin staining (H&E), and immunohistochemical staining (RANKL and OPG). RESULTS: On H&E analysis, the alendronate group showed greater amounts of non-vital bone, biofilm, inflammatory infiltrate and root fragment, and smaller amount of vital bone. The strontium ranelate group showed great amount of non-vital bone. This group also had lower levels of OPG, while the alendronate group showed lower OPG and RANKL than the other groups. On SEM analysis, the alendronate group showed a considerable number of microcracks on the alveolar bone surface and few Howship lacunae and lack of bone cells as well. The raloxifene, strontium ranelate, and control groups showed a large number of bone cells and Howship lacunae on the bone surface and few microcracks. CONCLUSION: Alendronate therapy is associated with macro- and microscopic features of medication-related osteonecrosis of the jaw at tooth extraction sites, whereas raloxifene therapy is not, and strontium ranelate therapy is associated with non-vital bone. CLINICAL RELEVANCE: Osteonecrosis of the jaws is a serious side effect of alendronate therapy, where tooth extraction is a major risk factor. Considering the significant number of patients undergoing antiresorptive therapies worldwide, the present study investigated whether raloxifene and strontium ranelate interfere with bone repair after tooth extraction in a similar way to bisphosphonates.

Quantitative Assessment of Dentinal Tubule Disinfection in Absence of Biofilm on Root Canal Walls: An in vitro Study.

Introduction: This study aimed at assessing the quantitative effect of calcium hydroxide, 2% chlorhexidine gel, and 1.5% chlorhexidine linked to xanthan gel specifically against intratubular bacteria. Methods and Materials: Fifty-two semi-cylindrical bovine dentin specimens were infected with Enterococcus (E.) faecalis by centrifugation with subsequent 7-days incubation. The surface of specimens was disinfected with 3% H2O2. Scanning electron microscopy (SEM), confocal laser scanning microscopy (CLSM) and the count of bacterial colony-forming units (CFU/mg) were used to assess dentin infection. A total of 40 specimens were incubated for 2 weeks with one of the intracanal medication applied (10 samples for each group): 1) calcium hydroxide, 2) 2% chlorhexidine gel, 3) 1.5% chlorhexidine linked to xanthan gel and 4) sterile saline. Final passive ultrasonic irrigation with 3% sodium hypochlorite was performed in half of the total specimens. The effect of intracanal medications and irrigation against intratubular bacteria was assessed by bacterial culturing of dentin shavings. Two-Way ANOVA model was applied followed by post-hoc Tukey's test for multiple pair-wise comparisons of mean CFU/mg values. Results: SEM, CLSM, and bacterial culturing confirmed the absence of the surface biofilm on the root canal wall and showed vital intratubular bacteria at the depth up to 700  m. Two-week application of 1.5% chlorhexidine with xanthan gel and 2% chlorhexidine gel significantly decreased intratubular bacterial counts compared with saline (P=0.0003 and P=0.0005, respectively). Subsequent passive ultrasonic irrigation with 3% sodium hypochlorite significantly reduced the number of intratubular bacteria in all groups except for the group with 1.5% chlorhexidine-xanthan gel (P=0.0054). Conclusion: This modified ex vivo model study showed ultrasonically activated irrigation with sodium hypochlorite had greater effect on intratubular bacteria counts compared with 2-week application of intracanal medications.

High percentage of microbial colonization of osteosynthesis material in clinically unremarkable patients.

Stabilization of fractures with internal fixation devices is a common procedure and implant-associated infections are a dreaded complication. The exact pathomechanism is not completely understood; however, microbial colonization of osteosynthesis material is considered a trigger for infection. This study aimed to determine the colonization rate of osteosynthesis implants in patients with no clinical or laboratory signs of infection, using two methods, conventional culture and polymerase chain reaction (PCR) of sonication fluid. Fifty-seven patients aged between 18 and 79 years without signs of infection who underwent routine removal of osteosynthesis devices between March 2015 and May 2017 were included in this study. Osteosynthesis material was investigated by sonication followed by cultivation of the sonication fluid in blood culture bottles and PCR analysis, simultaneously. Additionally, electron scanning microscopy was performed in nine representative implants to evaluate biofilm production. Thirty-two (56.1%) implants showed a positive result either by culture or PCR with coagulase-negative staphylococci being the most commonly identified microorganism (68.1%). Furthermore, the detection rate of the culture (50.9%) was significantly higher compared to PCR (21.1%). The scanning electron microscopy imaging demonstrated biofilm-like structures in four of six culture and/or PCR-positive samples. This study is the first, to the best of our knowledge, to demonstrate bacterial colonization of osteosynthesis implants in healthy patients with no clinical or laboratory signs of infection. Colonization rate was unexpectedly high and conventional culture was superior to PCR in microbial detection. The common understanding that colonization is a trigger for infection underlines the need for strategies to prevent colonization of implant material like antibiotic-loaded coating or intraoperative gel application.

Biocompatibility of Yttria-Tetragonal Zirconia Polycrystal Seeded with Human Adipose Derived Mesenchymal Stem Cell.

INTRODUCTION: The scaffold is a place for regeneration of new bone and bone tissue growths in tissue engineering applications. hADMSC is a multipotent cell which can differentiate into osteogenic, chondrogenic and adipogenic. Y-TZP has been shown to have several advantages over other ceramics because of its hard nature, namely fracture toughness and high flexural strength. AIM: This study aimed to analyze the biocompatibility of Y-TZP as a scaffold seeded with hADMSCs by in vitro analysis. MATERIAL AND METHODS: This research involved several processes, namely Y-TZPS manufacture process, XRD examination, differentiation and characterization of hADMSC, SEM observation, and then TT. RESULTS: The results of the XRD examination showed that Y-TZPSs had sharp peaks. It suggests that they had high crystal purity. The marked expression of the characterization of hADMSC is the positive expression of Cluster of differentiation (CD), namely CD 90, CD 73 and CD 105 above NMT and negative expressions of CD 14, CD 19, CD 34, CD 45 and also HLA-DR below NLT. The analysis of observations on the Y-TZPSs with SEM, subsequently, indicated the porosity of Y-TZPSs, as a result, the adhesion of HADMSCs occurred and grew in the porosity in the Y-TZPSs. CONCLUSIONS: Y-TZPSs with low porosity and toxicity can be able to proliferate and differentiate if seeded with hADMSC. Y-TZPSs are expected to be used as implantable biomaterials using hADMSCs with high biocompatibility.

Rubbing time and bonding performance of one-step adhesives to primary enamel and dentin

Abstract Objectives: This study investigated whether increasing the concentration of acidic monomers in one-step adhesives would allow reducing their application time without interfering with the bonding ability to primary enamel and dentin. Material and methods: Experimental one-step self-etch adhesives were formulated with 5 wt% (AD5), 20 wt% (AD20), or 35 wt% (AD35) acidic monomer. The adhesives were applied using rubbing motion for 5, 10, or 20 s. Bond strengths to primary enamel and dentin were tested under shear stress. A commercial etch-and-rinse adhesive (Single Bond 2; 3M ESPE) served as reference. Scanning electron microscopy was used to observe the morphology of bonded interfaces. Data were analysed at p<0.05. Results: In enamel, AD35 had higher bond strength when rubbed for at least 10 s, while application for 5 s generated lower bond strength. In dentin, increased acidic monomer improved bonding only for 20 s rubbing time. The etch-and-rinse adhesive yielded higher bond strength to enamel and similar bonding to dentin as compared with the self-etch adhesives. The adhesive layer was thicker and more irregular for the etch-and-rinse material, with no appreciable differences among the self-etch systems. Conclusion: Overall, increasing the acidic monomer concentration only led to an increase in bond strength to enamel when the rubbing time was at least 10 s. In dentin, despite the increase in bond strength with longer rubbing times, the results favoured the experimental adhesives compared to the conventional adhesive. Reduced rubbing time of self-etch adhesives should be avoided in the clinical setup.

The Effect of Er:YAG Laser Irradiation and Different Concentrations of Sodium Hypochlorite on Shear Bond Strength of Composite to Primary Teeth's Dentin.

Introduction: The aim of this study was to evaluate the effect of various concentrations of NaOCl on shear bond strength of composite resin to dentin of primary teeth, prepared with laser and bur. Methods: In this in vitro study, 48 primary molars were sectioned at mesiodistal direction and were randomly divided into 6 groups; G1: bur, G2: bur + NaOCl 2.5%, G3: bur + NaOCl 5.25%, G4: laser, G5: laser + NaOCl 2.5%, G6: laser + NaOCl 5.25%. One-Step Plus adhesive was applied after phosphoric acid gel and NaOCl over the dentin surfaces for all groups, and composite resin cylinders were bonded to the samples. After thermocycling, shear bond strengths of composite resin to dentin were measured and statistical analyses were done by means of t test and analysis of variance (ANOVA). Results: The mean shear bond strength showed no significant difference between the groups prepared with bur (13.82 ± 3.49) and laser (14.18 ± 3.65) (P > 0.05). The mean difference of shear bond strength between three groups G1, G2 and G3 and between G4, G5 and G6 were not statistically significant (P > 0.05). Scanning electron microscopy (SEM) figures showed an irregular surface in laser groups and fairly complete removal of smear layer from the orifices of the dentinal tubules, in the group in which NaOCl was used. Conclusion: The application of different concentrations of NaOCl does not significantly improve the bond strength in dentin surfaces prepared with laser or bur.

Effects of Root Debridement With Hand Curettes and Er:YAG Laser on Chemical Properties and Ultrastructure of Periodontally-Diseased Root Surfaces Using Spectroscopy and Scanning Electron Microscopy.

Introduction: The efficacy of erbium-doped yttrium aluminum garnet (Er:YAG) laser for root debridement in comparison with curettes has been the subject of many recent investigations. Considering the possibility of chemical and ultra-structural changes in root surfaces following laser irradiation, this study sought to assess the effects of scaling and root planing (SRP) with curettes and Er:YAG laser on chemical properties and ultrastructure of root surfaces using spectroscopy and scanning electron microscopy (SEM). Methods: In this in vitro experimental study, extracted sound human single-rooted teeth (n = 50) were randomly scaled using manual curettes alone or in conjunction with Er:YAG laser at 100 and 150 mJ/pulse output energies. The weight percentages of carbon, oxygen, phosphorous and calcium remaining on the root surfaces were calculated using spectroscopy and the surface morphology of specimens was assessed under SEM. Data were analyzed using one-way analysis of variance (ANOVA). Results: No significant differences (P > 0.05) were noted in the mean carbon, oxygen, phosphorous and calcium weight percentages on root surfaces following SRP using manual curettes with and without laser irradiation at both output energies. Laser irradiation after SRP with curettes yielded rougher surfaces compared to the use of curettes alone. Conclusion: Although laser irradiation yielded rougher surfaces, root surfaces were not significantly different in terms of chemical composition following SRP using manual curettes with and without Er:YAG laser irradiation. Er:YAG laser can be safely used as an adjunct to curettes for SRP.

Inhibition of expression of P-selectin by antioxidant in cholesterol-fed rats

Butylated hydroxytoluene (BHT) can inhibit experimental atherosclerosis in animals. Although the agent is an antioxidant, the exact mechanism of the reaction in atherosclerosis is still unknown. To investigate the effects of BHT on expression of P-selectin (PADGEM, GMP-140), intercellular adhesion molecule-1 (ICAM-1) and class II MHC (Ia) antigen, we proposed an experiment on rats. Male rats (n=18 per group) were fed either a normal cholesterol control diet, a normal cholesterol diet containing 0.5% BHT (BD), a high cholesterol diet containing 1.5% cholesterol and 0.1% sodium cholate (CD), or the CD diet containing 0.5% BHT (BCD). Rats were sacrificed after 3 days, and after 1, 2, 4, 10, and 17 weeks of dietary treatment. Although there was no gross or light microscopic atherosclerotic lesions, scanning electron microscopy revealed monocytic adhesion to aortic endothelium and mild endothelial injuries in CD and BCD groups. Immunohistochemically, the addition of BHT to a high cholesterol diet inhibited P-selectin expression but not in ICAM-1 and Ia antigen. These findings suggest that in rats, high cholesterol diets induce expression of ICAM-1, P-selectin and Ia antigen. In addition, the antiatherogenic effect of BHT may play a role in the inhibition of P-selectin.