Tag Formation Research Articles

Potential of 5% tamarind extract gel as an etching agent: tensile strength and scanning electron microscope (SEM) evaluation

Background: Acid etching is a stage in obtaining bonds between composites and enamel. The application of acid to the enamel surface, however, can cause dissolution of hydroxyapatite and demineralisation of the enamel surface. Phosphoric acid, a strong acid, is an etching material that can reduce enamel hardness. Excessively reducing hardness can interfere with attachment to the restorative material. One medicinal plant that can be used as an alternative material in acid etching is tamarind. Purpose: This study aims to determine the effect of 5% tamarind extract gel on the tensile strength of composite resins. Methods: This is an experimental research study with a post-test-only control-group design. The study used 14 mandibular incisors. The labial part of the incisor was prepared using a diamond fissure bur with a diameter of 4 mm and a depth of 2 mm. The control group was then etched with 37% phosphoric acid gel, while the experimental group was etched with 5% tamarind extract gel. Bonding resins and micro-hybrid composite resins were applied, based on the manufacturers’ instructions. Next, a tensile strength test and seeing formation resin tags by scanning electron microscope (SEM) were performed. Data were analysed using an independent t-test (p < 0.05). Results: The average tensile strength of composite resins in the group etched with 5% tamarind extract gel was the same as in the 37% phosphoric acid group (p > 0.05). SEM images also show that enamel etched with 5% tamarind extract gel produced a tag similar to that etched with 37% phosphoric acid gel. Conclusion: 5% tamarind extract as an etching material can generate tensile strength of composite resin and trigger formation of resin tags in the same way as 37% phosphoric acid.

Crystal Structure of the Mannose-6-Phosphate Uncovering Enzyme

Most lysosomal hydrolytic enzymes reach their destination via the mannose-6-phosphate (M6P) pathway. The enzyme N-acetylglucosamine-1-phosphodiester α-N-acetylglucosaminidase (NAGPA, or "uncovering enzyme") catalyzes the second step in the M6P tag formation, namely the removal of the masking N-acetylglucosamine (GlcNAc) portion. Defects in this protein are associated with non-syndromic stuttering. Togain a better understanding of the function and regulation of this enzyme, we determined its crystal structure. The propeptide binds in a groove on the globular catalytic domain, blocking active site access. High-affinity substrate binding is enabled by a conformational switch in an active site loop. The protein recognizes the GlcNAc and phosphate portions of its substrate, but not the mannose moiety of the glycan. Based on enzymatic and 1H-NMR analysis, a catalytic mechanism is proposed. Crystallographic and solution scattering analyses suggest that the C-terminal domain forms a long flexible stem that extends the enzyme away from the Golgi membrane.

Influences of desensitizing agents on bond strength of etch-and-rinse and self-etch adhesive system to dentin.

Background:Cervical lesions requiring adhesive restoration may present with dentin hypersensitivity, but the effect of desensitizer treatment on microtensile bond strength (MBS) is inconclusive.Aim:The aim of the present study was to assess the influence of two types of dentin desensitizing treatment on bond strength to dentin.Materials and Methods:Thirty-six extracted human mandibular first premolars were used to obtain superficial buccal cervical dentin. The samples were assigned to two groups (18/group): etch-and-rinse (ERS) (Optibond® Solo) and self-etch (Palfique) adhesive systems. Eighteen teeth in each group were randomly assigned to three desensitizer treatments (6/treatment); control (no desensitization), Gluma™ desensitizerand Novamin-containing toothpaste (Sensodyne repair and protect™). Bonded dentin-composite specimens were stored in artificial saliva for 2 weeks prior to scanning electron microscope (SEM) evaluation and MBS testing. Univariate analysis of variance and Tukey tests were performed (α = 0.05) for the data analysis.Results:The mean MBS with self-etch system (SES) was significantly higher than ERS system, irrespective of the dentin desensitizer regimen. SEM showed no hybrid layer or resin tag formation in the SES group. Tubular occlusion was observed in all specimens treated with desensitizer.Conclusion:Mild self-etch adhesive can be used on dentin treated with Gluma or bioglass-containing desensitizer without compromising the bond strength.Clinical Relevance:Dentin desensitizer such as in-office Gluma or at-home Novamin-containing toothpaste could be used without compromising the bond strength of mild self-etch adhesive systems.

Ex Vivo Evaluation of a Restoration Protocol for Teeth with Simulated Incomplete Rhizogenesis

The use of phosphate buffered saline (PBS) as an intracanal medication triggers a biomineralization process within mineral trioxide aggregate (MTA) apical plugs during the apexification process in teeth with incomplete rhizogenesis. However, no consensus is available in the literature regarding a restorative protocol for this type of treatment. Thus, the objective of this study was to use scanning electron microscopy (SEM) to evaluate the processes of biomineralization and adhesion in a restorative protocol for teeth with simulated incomplete rhizogenesis. Methodology: Root sections with a thickness of 2mm and cavities with a diameter of 2mm were used. The sections were randomly prepared and filled with the following materials: Group 1 (n=12), ProRoot MTA; and Group 2 (n=12): MTA Exp. Subsequently, the samples were immersed in PBS for 35 days. Every 5 days, the PBS was replaced, and the precipitates were collected, dried, and weighed. Two samples from each group were analyzed by SEM. Moreover, 24 single-rooted teeth were standardized, incomplete rhizogenesis was simulated, and 5-mm-long apical plugs were created with Pro Root MTA. As an intracanal medication, PBS was used for different periods of time: Group 1:48 h; Group 2:7 days; and Group 3:15 days. Then, fiberglass posts were cemented with the REBILDA® Post System. The samples were prepared and analyzed by SEM. Results: ProRoot MTA and MTA Exp effectively promoted the formation of carbonated apatite precipitates and biomineralization with dentin. ProRoot MTA yielded more carbonated apatite precipitates compared to MTA Exp (p=0.0536). The use of PBS as an intracanal medication for 7 and 15 days promoted intratubular mineralization (MIT), and treatment for 15 days was more effective (p < 0.05). The REBILDA® Post System effectively promoted the microimbrication of the adhesive system and the formation of resinous tags with lateral adhesive branches. Conclusion: Apexification with MTA associated with the use of PBS as an intracanal medication for 15 days, in addition to the use of the REBILDA® Post System, seems to be a feasible restorative protocol.

Correlation between Bond Strength to Dentin and Sealers Penetration by Push-Out Test and CLSM Analysis.

This study correlated the bond strength (BS) and dentin penetration of different sealers by push-out test and Confocal Laser Scanning Microscopy (CLSM) analysis. Forty-five root canals were prepared according to the crown-down technique and filled with gutta-percha associated to the following sealers (n=15): Endofill, AH Plus and MTA Fillapex. Five canals of each group were filled with the sealers added with 0.1% Rhodamine B dye. Next, the specimens were transversely sectioned and submitted to the push-out test (n=10) and CLSM analysis (n=5). The BS data showed the following means (MPa) and standard deviation: AH Plus (4.17±1.86); MTA Fillapex (3.13±1.96) and Endofill (2.10±1.03). Statistical analysis (two-way ANOVA, α=0.05) showed significant difference among sealers (p<0.001) and root canal thirds (p<0.001). The BS results of Endofill and MTA Fillapex were statistically similar (p>0.05), however, they were statistically different from AH Plus (p<0.001). The regional analysis of BS showed similarity between middle and apical thirds (p>0.05), and both were different from coronal portion (p<0.001). CLSM analysis verified tags formation in all groups and higher penetration of the specimens filled with AH Plus (p<0.05). The Kendall test (correlation between BS to dentin and sealer penetration into dentinal tubules) and the Pearson test (between failures pattern and sealer penetration into dentinal tubules) did not show correlation between the variables evaluated for all the tested sealers (p>0.05). AH Plus group had higher BS to dentin, and deeper tags formation than the other sealers. There was no significant correlation between BS and intratubular penetration of the tested sealers.

Bonding Performance of Universal Adhesive Systems Applied in Etch-and-Rinse and Self-Etch Strategies on Natural Dentin Caries.

This study investigated the bonding performance of three universal adhesive systems applied using etch-and-rinse (ER) or self-etch (SE) strategies on natural dentin caries. Sixty human third molars were selected for this study: 30 naturally carious (CAD) and 30 sound (SD) teeth. The dentin surfaces were exposed, and teeth were randomly assigned to each evaluated adhesive system: Scotchbond Universal (SBU), Futurabond U (FBU), and Prime&Bond Elect (PBE) and an adhesive strategy: ER or SE. The adhesive systems were applied following the manufacturer's instructions, and the teeth were restored using a resin composite (Filtek Supreme Ultra, 3M). After 24 hours (distilled water at 37°C), samples were sectioned and evaluated using microtensile bond strength analysis (μTBS), micro-Raman spectroscopy to evaluate the degree of conversion within the hybrid layer (DC), and scanning electronic microscopy (SEM) to describe the morphology of the hybrid layer. The μTBS and DC data were analyzed using three-way analysis of variance and Tukey's test for means comparison (α=0.05). The SEM images were analyzed qualitatively. Reduced μTBS values were observed when comparing CAD with SD, regardless of adhesive system or strategy (p<0.0001). SBU showed statistically higher μTBS for both dentin substrates and strategies (p<0.0001). Furthermore, SBU showed greater integrity of the hybrid layer and resin tag formation compared with FBU and PBE. Mean μTBS values for FBU were higher for SD in the SE mode, whereas higher mean μTBS values were observed for CAD in the ER mode, both compared with PBE (p<0.001). Bonding performance is reduced on a caries-affected substrate. The ER strategy was not able to improve the bonding performance on natural CAD for universal adhesive systems. Improved bonding performance was obtained when using the Scotchbond Universal system.

Inhibitory effect of zinc-containing desensitizer on bacterial biofilm formation and root dentin demineralization.

This study compared the effect of a novel zinc containing, Caredyne Shield (CS), and a fluoroaluminocalciumsilicate-based, Nanoseal (NS) desensitizers on dentin tubule occlusion, inhibition of Streptococcus mutans (S. mutans) biofilm growth, and resistance to bacterial demineralization. Desensitizers were applied to simulated hypersensitive bovine dentin, with distilled water used as a control. S. mutans biofilms were grown on the surface of each specimen in an oral biofilm simulator. CS showed the least bacterial count and water insoluble glucan amount followed by NS. Transverse micro radiography revealed that both CS and NS showed significant reduction in mineral loss and lesion depth of the associated lesion. Scanning electron micrographs showed that the two desensitizers formed obvious depositions on the dentin surfaces, occlusion of tubules and mineral tag formation.

Correlation of serum lipid profile with leptin levels of skin tags patients

Skin tags may be associated with increased adipose deposition. Mechanism of skin tags formation is through the activation of leptin receptor in the dermis and epidermis. Recent study suggested that the presence of skin tags is associated with obesity, abnormal lipid profile and elevated serum leptin levels. Researcher are interested to analyse the correlation betwen serum lipid profile and leptin levels of patients with skin tags. This is a cross sectional study, conducted from October 2017 to February 2018 at Tumor and Dermatosurgery Divison-Dermatology and Venereology Department outpatient clinic in Dr. Mohammad Hoesin General Hospital Palembang. Sample study was obtained with consecutive sampling. There were 40 patients with skin tags that met the inclusion criteria included in the study. Serum lipid profile and serum leptin were measured. Statistic significant correlation between triglycerides and leptin levels was found (p=0.04; r=0.327), however there was no significant correlation between total cholesterol, LDL, HDL cholesterol with leptin levels (p=0.273; r=0.177, p=0.288; r=0.172, p=0.794; r=0.043). Triglyceride levels was found to have significant correlation with leptin levels.

Novel self-bonding composites: resin-dentin interfacial chemistry

Introduction: The biggest shortcoming of adhesive restorations is their susceptibility to bond degradation, when the substrate is dentin [1]. Since the quality of the resin-dentin interface relies mainly on its nanostructure [2], it is important to study the hybridization process in self-adhesive composites. Knowledge of the resin-dentin interface chemistry will provide insight into bonding, and possible susceptibility towards degradation [3]. Materials and methods: 9 primary teeth, obtained with informed consent from the Eastman Dental Hospital, previously approved by the EDI/EDH Joint Research & Ethics Committee were sectioned to obtain flat dentin surfaces, polished with 500 SiC grit paper and etched before material placement. The teeth were randomly divided (n = 3) between 3 materials - Activa ™ BioActive Restorative and 2 experimental composites. The experimental flowable composites had different levels of monocalcium phosphate (MCPM) and antibacterial polylysine (PLS) powders added to the filler phase. Restored teeth were stored in DI water for 24 h and vertically sectioned to obtain slabs perpendicular to the interface. Raman spectroscopy (Horiba Jobin Yvon, Paris, France) was used to research the chemistry of the resin-dentin interface. Three different lines were analysed in each sample to ensure reproducibility. Means corresponding to resin and dentin peaks were calculated and plotted using Microsoft Excel Tools (v15.30, Redmond, Washington, USA). FE-SEM (Phillip XL-30, Eindhoven, The Netherlands) was used to gather microstructural imaging of the interface. Results: Differences in chemical composition of the resin-dentin interface was found within interfacial regions ranging from 4 to 8 μm deep. Spectra obtained in mineralized dentin confirmed material diffusion and penetration in all cases. Doubling the hydrophilic additives in experimental composites, increased the resin infiltration depth by almost two-fold and affected the apatite to collagen ratio variation within the interface. SEM imaging confirmed resin tag formation, with all materials. Discussion and conclusions: No distinct hybrid layer was found at the interfaces, which is in accordance with previous studies [4,5]. However, resin infiltration was observable with all materials, providing evidence of envelopment and micromechanical interlocking. A gradual transition from dentin to pure material confirmed the presence of an interdiffusion zone [6] which was enhanced with increased hydrophilic additives. These results confirm micromechanical interlocking with dentin is achieved in both the experimental and commercial materials.

Dry-bonding to dentin using alternative conditioners based on iron-containing solutions or nitric acid

ObjectivesTo evaluate the effect of experimental conditioners (10–3 solution − 10–3, 6.8% ferric oxalate - FOX, and 1.4% nitric acid - NI) on dentin elastic modulus, flexural strength, bond strength, failure mode, and adhesive interface morphology of two etch-and-rinse adhesives (XP Bond, Dentsply or One-Step, Bisco) applied on etched dry dentin. MethodsSound human third molars were used for the microtensile bond strength test (n = 8), performed at 24 h and after one year of water storage. Failure modes were evaluated by scanning electron microscopy. Dentin bonding interface was analyzed by confocal laser scanning microscopy (n = 3). Adhesive systems were applied on phosphoric acid-etched, wet (positive control) and dry (negative control) dentin, and on etched and dry dentin previously treated with 10–3 (15s), FOX (60s), or NI (15s). Bovine dentin bars (n = 15) were immersed into the conditioning solutions and subjected to a three-point bending test. ResultsXP Bond + 10–3 or NI resulted in lower bond strength than phosphoric acid. One-Step + 10–3 or NI resulted in bond strengths equivalent to the positive control. Experimental conditioners presented no bond strength reduction after one year, regardless of the bonding agent tested. One-Step resulted in more adhesive failures than XP Bond at 24 h, and mixed failures increased after storage. All experimental conditioners promoted hybridization and resin tags formation, except FOX. Dentin elastic modulus was not affected by the conditioners, whereas flexural strength was significantly reduced by FOX. ConclusionsAdequate and stable dentin bonds were achieved when the bonding agents were applied on 10–3 or NI-treated dentin. None of the experimental conditioners reduced dentin elastic modulus, but dentin flexural strength was significantly reduced by FOX-conditioning.

Assessment of sealing ability of two root-end filling materials at different depths: A comparative study

Background: Most biocompatible and least microleakage of root-end filling material helps the clinician to provide a proper apical seal that prevents the movement of bacteria and the spreading of their remnants from the root canal system into the periapical tissues. The aim of this study was to compare the sealing ability of biodentine and mineral trioxide aggregate (MTA) as root-end filling material at different depths. Materials and Methods: For this study, 100 freshly extracted maxillary central and lateral incisor teeth were taken and stored in normal saline. All teeth were divided into four experimental groups: Group 1––filled with biodentine; Group 2––filled with MTA; Group 3––positive control group; and Group 4––negative control group. Groups 1–3 were divided into three subgroups, which comprised 10 teeth each. The teeth were immersed in methylene blue dye (Thermo Fisher Scientific, Mumbai, India) for 72h. The depth of dye penetration was examined under a stereomicroscope (Magnus, Olympus, Noida, India) with a ×10 eyepiece magnification and ×2 zoom to evaluate the roots for the extent of microleakage. Results: On biodentine filling, at 3 mm showed the least mean (126.72 ± 111.87) followed by 4 mm (137.28 ± 111.87) and 2 mm (195.36 ± 182.99) deep cavities, respectively. On MTA filling, at 4 mm showed the least mean (902.88 ± 321.12) followed by 3 mm (924.00 ± 303.06) and 2 mm (1404.48 ± 539.72) deep cavities, respectively. Conclusion: On conclusion, both the materials tested showed dye penetration but there was significantly less dye penetration in biodentine, which may be because of its smaller particle size and formation of mineral tags, which may offer more resistance to microleakage than MTA at a similar depth.

Nanotechnology in Dentin Disinfection: Can We Preserve the Bond?

ABSTRACTAimsThe aim of this study is to evaluate the effect of cavity disinfection with 2% chlorhexidine (CHX) and Ag–Au nanoparticles on microleakage and resin tag penetrability of composite restoration under in vitro conditions.Materials and methodsTwenty-five human permanent molars extracted for therapeutic reasons were used in the study. Class V cavity of standard dimension was prepared on the buccal and lingual surfaces of the teeth. The teeth were randomly allocated into two groups based on the cavity disinfectant used: group I being 2% CHX gluconate (chlorhexidina Friedrich and Bianca Mittelstadt (FGM)) and group II being cavity disinfectant containing Ag–Au nanoparticles (nanocare gold). In both the groups, the dentin was etched with 37% phosphoric acid and cavity disinfectants were applied following which dentine bonding agent and composite resin were applied and cured. The specimens were then viewed under a stereomicroscope and a scanning electron microscope for microleakage and resin tag formation, respectively.ResultsThe results were statistically analyzed using an independent “t” test. No significant difference was seen between the two groups with respect to both microleakage and resin tag penetration values (p > 0.05).ConclusionThe cavity disinfectant containing Ag–Au nanoparticles did not affect the sealing ability and resin tag penetrability of composite resin in permanent molars when compared with 2% CHX.How to cite this articleAttiguppe P, Tripathi AP, et al. Nanotechnology in Dentin Disinfection: Can We Preserve the Bond? Int J Clin Pediatr Dent 2019;12(1):42–46.

Analysis of the bond interface between self-adhesive resin cement to eroded dentin in vitro.

The purpose of this study was to evaluate the bonding interface between a self-adhesive resin cement to in vitro eroded dentin. Seventy-two third molars were used and divided into two groups: sound dentin and in vitro eroded dentin. The in vitro erosion was performed following a demineralization protocol, in which the specimens were immersed in a demineralizing solution for 2 minutes per cycle and remineralizing solution for 10 minutes per cycle for 9 days. Both groups were submitted to four dentin surface treatments: control group (without any treatment), 2% chlorhexidine, 20% polyacrylic acid, and 0.1 M EDTA (n = 9). Blocks of resin-based composite were bonded with RelyX U200 self-adhesive resin cement applied on the pretreated dentin surfaces. The teeth were sectioned into beams (1mm2) and submitted to microtensile bond strength testing to evaluate the bond strength of self-adhesive resin cement to dentin after 24 hours and 8 months of immersion in artificial saliva. Three specimens of each group were longitudinally cut and evaluated using confocal laser scanning microscopy to analyze the dentin/cement interface. Eroded dentin showed higher bond strength values when compared to sound dentin for the 2% chlorhexidine group (p = 0.03), 24 hours after adhesion. When considering eroded dentin, the 0.1M EDTA group showed higher bond strength values with a statistically significant difference only for the control group (p = 0.002). After 8 months of storage, the present results showed that there was no statistically significant difference between the two substrates for all experimental groups (p>0.05). Analysis of the microscopy confocal showed different types of treatments performed on dentin generally increased tags formation when compared to the control group. The eroded dentin showed a significant increase in density and depth of resinous tags when compared to sound dentin. The storage of samples for 8 months seems to have not caused significant degradation of the adhesive interface.

Comparison of clinical efficacy and safety of two kinds of surgical method in the treatment of mixed hemorrhoids for III~IV stage combined with internal rectal mucosal prolapsed

Objective To compare the clinical efficacy and safety of two kinds of surgical method including Milligan-Morgan haemorrhoidectomy and automatic ligation of hemorrhoids in the treatment of mixed hemorrhoids for Ⅲ-Ⅳ stage combined with internal rectal mucosal prolapse. Methods From March 2013 to July 2015, 100 patients with mixed hemorrhoids for Ⅲ-Ⅳ stage combined with internal rectal mucosal prolapse were chosen in the Traditional Chinese Medicine Hospital of Qingyuan County, and they were randomly divided into two groups according to the digital table, with 50 patients in each group.A group received Milligan-Morgan haemorrhoidectomy, and B group received automatic ligation of hemorrhoids.The clinical effect, the level of clinical indicators in peri-operative period, the scores of pain, bleeding, anal edema and dysuria after treatment and the skin tag formation rate of the two groups were compared. Results The short-term effective rates of A group and B group were 76.00%, 96.00%, respectively.The clinical effect of B group was better than that of A group, and the difference was statistically significant(χ2=7.73, P<0.05). The operation time, blood loss volume, wound healing time and total hospitalization time of A group were(20.97±4.52)min, (12.47±1.65)mL, (25.48±3.76)d, (15.55±4.38)d, respectively, which of B group were(12.01±2.54)min, (7.29±1.02)mL, (20.24±2.18)d, (12.02±3.82)d, respectively.The levels of clinical indicators in peri-operative period of B group were better than those of A group, and the differences were statistically significant(t=2.74, 3.02, 2.84, 3.46, all P<0.05). The scores of pain, bleeding, anal edema and dysuria after treatment of B group were lower than those in A group and before treatment, the differences were statistically significant(t=2.67, 2.50, 3.04, 2.76, all P<0.05). The skin tag formation rate of B group was lower than that of A group and before treatment, and the difference was statistically significant(χ2=8.77, P<0.05). Conclusion Compared with Milligan-Morgan haemorrhoidectomy, automatic ligation of hemorrhoids in the treatment of mixed hemorrhoids for III-IV stage combined with internal rectal mucosal prolapse can efficiently relieve the clinical symptoms and signs, promote wound healing and is helpful to reduce the postoperative complications risk. Key words: Hemorrhoids; Haemorrhoidectomy; Ligation

The effects of different irrigation solutions on the bond strength of cemented fiber posts.

ObjectiveTo study effect of root canal irrigant solutions on the bond strength of cemented fiber posts, and resin cement-tags in root canal dentin.Materials and methodsFifty-two human single-rooted anterior teeth were selected and stored in 1% sodium azide. Crowns were sectioned 2 mm incisal to the cemento enamel junction with diamond bur at high speed under water-cooling. After standard root canal treatment to tested teeth, they were randomly assigned into four groups (n=13) corresponding to the endodontic irrigant solution that was used during post space preparation. The treatment groups were: Group 1: 6.15% sodium hypochlorite; Group 2: 17% EDTA; Group 3: 6.15% NaOCl +17% EDTA; Group 4: 6.15% NaOCl +0.12% chlorhexidine solution. Parallel-sided fiber posts were used for all specimens. Samples were embedded in a cylindrical PVC mounting jig to facilitate perpendicular sectioning. With low speed diamond saw, cervical and apical specimens from each tooth were obtained and subjected to push-out test using universal testing machine. SEM was used to examine the root-canal dentin surface.ResultsStatistical analysis revealed significant difference among the groups at P<0.05. Group 2 treated with EDTA, had the highest bond strength; 18.63±2.85 MPa in cervical specimens and 13.49±3.67 MPa in apical specimens. The cervical specimens of Groups 2 and 3 were significantly different than the apical specimens in the same group. Adhesive failure between cement and dentin was the main failure mode observed in all groups. Groups irrigated with EDTA showed cleaner dentin surface and better resin tag formation, while groups treated with NaOCl showed less resin tag formation and insufficient smear layer removal.ConclusionNaOCl had adverse effect on bond strength of self-adhesive resin cement to radicular dentin. EDTA irrigant solution produced higher bond strength and was more effective in removing smear layer than NaOCl.

A 4 K FT-ICR cell for infrared ion spectroscopy.

We present the design of the newly constructed cryogenic Fourier-transform ion cyclotron resonance (FT-ICR) ion trap for infrared ion spectroscopy. Trapped ions are collisionally cooled by the pulsed introduction of buffer gas into the cell. Using different buffer gases and cell temperatures, we record action spectra of weakly bound neutral gas-analyte complexes with an IR laser source. We show for the first time that ion-He complexes can be observed in an ICR cell at temperatures around 4 K. We compare the experimental vibrational spectra of Ag(PPh3)2+ obtained by tagging with different neutral gases: He, Ne, Ar, H2, and N2 to computed vibrational spectra. Furthermore, the conditions necessary for the formation of neutral tags within an ICR ion trap are studied.

Synthesis of designer triglycerides by enzymatic acidolysis

Enzymatic acidolysis process was developed for modification of fully hydrogenated soybean oil (FHSO) by incorporation of caprylic acid, a medium chain fatty acid. Immobilized sn-1,3 specific lipase PyLip was used to modify FHSO to produce a new fat with improved physico-chemical and functional properties. PyLip mediated acidolysis resulted in 88% reduction of substrate triglycerides and 45.16% incorporation of caprylic acid in FHSO at molar ratio of 1:3 of FHSO and caprylic acid in 60 min reaction time. HPLC analysis revealed formation of mono-substituted and di-substituted TAGs post enzymatic acidolysis. Physical properties of synthesized lipid were studied using DSC and XRD and considerable change was observed in the final product compared to the starting material. The present study reports a faster acidolysis process in the presence of solvent enhancing the modification of FHSO with caprylic acid and having no side products formation (monoglycerides and diglycerides) making the entire process highly efficient and commercially attaractive.

Influences of the cold atmospheric plasma jet treatment on the properties of the demineralized dentin surfaces

Improvement of the bonding strength and durability between the dentin surface and the composite resin is a challenging job in dentistry. In this paper, a radio-frequency atmospheric-pressure glow discharge (RF-APGD) plasma jet is employed for the treatment of the acid-etched dentin surfaces used for the composite restoration. The properties of the plasma treated dentin surfaces and the resin–dentin interfaces are analyzed using the x-ray photoemission spectroscopy, contact angle goniometer, scanning electron microscope and microtensile tester. The experimental results show that, due to the abundant chemically reactive species existing in the RF-APGD plasma jet under a stable and low energy input operating mode, the contact angle of the plasma-treated dentin surfaces decreases to a stable level with the increase of the atomic percentage of oxygen in the specimens; the formation of the long resin tags in the scattered clusters and the hybrid layers at the resin–dentin interfaces significantly improve the bonding strength and durability. These results indicate that the RF-APGD plasma jet is an effective tool for modifying the chemical properties of the dentin surfaces, and for improving the immediate bonding strength and the durability of the resin-dentin bonding in dentistry.

Ideal parameters for femto-second laser-assisted anterior capsulotomy: Animal studies.

In femtosecond laser-assisted cataract surgery, the parameter such as horizontal spot spacing and energy level can be adjusted. Although there have been several studies reported on various laser systems, showing the effects of varying energy levels and horizontal spot spacing on lens capsulotomy cut edges, none have been reported on the Catalys laser system (Abbott Medical Optics, Inc., Santa Ana, CA). The aim of this study is to evaluate, using scanning electron microscopy (SEM), the quality of the cut edges of the laser lens capsulotomy obtained using the Catalys Laser System, using different horizontal spot spacing and energy levels, and to determine the ideal parameters based on SEM results. Fifty rabbit capsulorhexis specimens from a femtosecond laser with different spot spacing and energy settings were divided into five groups randomly. Spot spacing was 3 um and laser pulse energy was 4 uJ in group 1. The respective values were 5 um and 2 uJ in group 2, 5 um and 4 uJ in group 3, 5 um and 6 uJ in group 4, and 7 um and 4 uJ in group 5. All samples were evaluated using SEM to compare the number of tags per capsulotomy and the laser emission time. Group 1 had a significantly lower tag formation than groups 3 and 5 (P = 0.042 and 0.021, respectively). Although the laser emission time increased about 1.5 sec as the spot spacing increased from 3 to 7 um, the quality of the cut was smoother in group 1 because of overlapping effect of photodisruption cavities. There was no significant difference between groups 2, 3 and 4 at different laser energy settings. In an ex-vivo study, samples from an energy setting of 10 uJ showed increased irregularity and damage. The degree of irregularity was higher at increasing spot spacing and laser energy settings, with abundant tag formation. Dense spot spacing with low-energy settings provide a better cut quality, which is probably correlated with the reduction in anterior capsular tear complications.

Analysis of sealing ability of endodontic cements apical plugs.

BackgroundIt is unknown whether the bioactivity of Biodentine characterized by the precipitation of hydroxyapatite and formation of tags into the dentinal tubules improve its sealing ability as an apical plug. Aim: To evaluate the sealing ability provided by Biodentine and mineral trioxide aggregate (MTA) apical plugs, with or without phosphate-buffered saline (PBS) intracanal dressing, using a glucose leakage method.Material and MethodsThe space of the canal of 100 root segments with about 12 mm long was shaped using Gates-Glidden. After created an apical retrograde cavity, the root segments were randomly divided into 4 groups (n = 25): G1 – Biodentine; G2 - Biodentine + PBS intracanal dressing; G3 - MTA and G4 - MTA + PBS intracanal dressing. All access openings were filled with temporary cement and all root segments were introduced in floral foams moistened with PBS. After 2 months, all root segments were prepared to evaluate the glucose leakage. The amount of glucose leakage was quantified by a spectrophotometer and the data were analyzed using chi-square test (p<0.05).ResultsTraces of the glucose were observed in a higher of samples that received Biodentine apical plug (p<0.05). The exposure to intracanal PBS did not influence the sealing provided by Biodentine and MTA.ConclusionsThe Biodentine had lower sealing ability than MTA. The interaction with PBS intracanal dressing did not improve the sealing ability provided by sealers. Key words:Apexification, dental cements, dental leakage, glucose, pressure.