Evaluation of Fluoride Release in Chitosan-Modified Glass Ionomer Cements

OBJECTIVE

This study assessed the influence of chitosan nanoparticles on the fluoride-releasing ability of 4 glass ionomer cement (GIC) through an in vitro analysis.

METHODS

Four types of GIC (type II light cure universal restorative, type II universal restorative, GC Fuji VII, and type IX) were modified with nanochitosan particles; 10% chitosan was added to the glass ionomer liquid. Six specimens for each of the 4 groups were created, using expendable Teflon moulds. Discs of each type of GIC (n = 6) were immersed in deionised water at various time intervals. Electrodes selective for fluoride ions were employed to analyse the amount of released fluoride at 1, 7, 14, 21, and 28 days.

RESULTS

Chitosan-modified GICs showed greater fluoride release than conventional GICs at all time points. All samples showed an initial high release of fluoride that tapered off with time. The total amount of fluoride released increased from the 1st day to the 28th day on adding chitosan to all the 4 types of GIC. Amongst those, type IX high-strength posterior extra with chitosan released a considerably higher quantity of fluoride at all time intervals.

CONCLUSIONS

In all the experimental groups, adding chitosan to the glass ionomer liquid had an accelerating effect on its fluoride-releasing property.

A study on the development of scaffold fabrication using citric acid polyester – nanohydroxyapatite composite

ABSTRACT. Nano hydroxyapatite (n-HAp) and its composites have shown a great development in the field of tissue regeneration and in controlled drug delivery due to its good biocompatibility and bioactivity behavior. Furthermore, HAp-based nanocomposites enhance mechanical properties. These synthetic HAp nanocomposites can also be tailored to fabricate scaffold with controlled porosity which facilitate the growth of the cell in the field of tissue engineering. In this paper, we focus on the synthesis of nano hydroxyapatite (n-HAp) by sol-gel method. The synthesized nano powders were calcined at 500 oC and characterized by FT-IR, XRD and TEM. We have also described the synthesis of citric acid-based polyester by melt polycondensation method without adding catalyst. The monomers used were citric acid, 1,6-hexane diol and sebacic acid. The corresponding synthesized n-HAp/polyester composite have potential application in soft tissue engineering. The structures of polyester and its nanocomposite were studied by FT-IR and 1H NMR spectral studies. The thermal and mechanical properties of polyester, composites and cytotoxicity activity (MTT assay) using vero cells were also studied. Porous scaffold of the nano HAp/Polyester was fabricated by solvent-casting particulate leaching technique which is useful in the development of tissue engineering applications. SEM and TEM studies were carried out for nano HAp, polyester, composites and scaffold.   KEY WORDS: Cytotoxicity, Polycondensation, Sol-gel, Solvent-casting, Tissue engineering Bull. Chem. Soc. Ethiop. 2022, 36(4), 923-934.                                                                DOI: https://dx.doi.org/10.4314/bcse.v36i4.17                                                      

Malignant orbital teratoma in a neonate: A clinicopathological case report

Teratoma of the orbit is rare; very few cases have been published in literature. A case of orbital teratoma in a neonate is presented where the proptosis was massive enough to obscure the eyeball. Clinically, the diagnosis of teratoma was considered. As there was no possibility of salvaging the eye, exenteration of the orbit was done. Orbital teratomas are generally benign. Histopathological examination revealed the features of malignant teratoma.

Mass transger in an eccentric annular region through diffusion

The mass transfer in an eccentric annular region through diffusion by taking blood as a Newtonian fluid with the investigation of oxygen transfer and drug transport to the tissue cells in an eccentric catheterized artery is studied. The region bounded by eccentric circles in x-y plane is mapped conformally to concentric circles in ξ - η plane using a conformal mapping z = λ/1 - ζ. The resulting governing equations are analytically solved by using transformation for the concentration. Numerical computations are carried out to understand the simultaneous effects of absorption parameter and eccentricity on the flow. The observation through the numerical computation reveals that, as absorption parameter and eccentricity enhances, the solute concentration diminishes. This mathematical model provides an insight for physiologists to understand the drug transport to the tissues in various clinical treatments of cardiovascular diseases.

Prevalence of ancylostomiasis in people living in slum area, Philhousepet of Eluru, West Godavari District (Andhra Pradesh)

Hookworm infection was found in the slum area of Eluru, West Godavari District, A.P. which has scheduled caste population. Infection is related to different climatic conditions and socio-economic status of the population. The inhabitants are coolies in agricultural fields and household workers with a poor level of hygiene and sanitation. All the infected positive cases showed Ancylostoma duodenale infection. The prevalence of hookworm infection was 15.6, 17.9 and 14 % in children, 23.5, 27.9 and 20.5 % in adults during summer, rainy and winter seasons respectively. Single species infection was studied in three periods. Out of 264 faecal samples, 128 children (40 males, 32.5 %) and 136 adults (64 men, 25 % and 72 women, 30.5 %) showed helminthic infection in rainy season. Much variation is seen in the prevalence of disease in rainy and winter seasons in all the age groups. The infected individuals were treated with albendazole just after rainy season. Three weeks after antihelminthic treatment, the infection rate among them was lowered; health education also plays a role in reducing the % of infection.

Comparison of the push-out shear bond strength of four types of glass ionomers when used to bond amalgam: An in vitro study

Background:

Dental amalgam is the primary direct posterior restorative material used worldwide, but it have certain shortcomings due to the lack of adhesiveness to the cavity. The introduction of the concept of bonded amalgam helped improve the use of amalgam as a restorative material.

Aim:

Evaluation of the comparative push-out shear bond strength of four types of conventional glass ionomers used to bond amalgam to tooth in simulated class I situations.

Materials and Methods:

Four chemical cure glass ionomers are used: GC Fuji I, GC Fuji II, GC Fuji III and GC Fuji VII, and are compared with unbonded amalgam. The push-out bond strength was tested using the Instron Universal Testing Machine at a crosshead speed of 0.5 mm/min.

Statistical Analysis:

One-way ANOVA and post hoc Bonferroni tests were used to analyze the data.

Results:

The results showed that the use of glass ionomer to bond amalgam resulted in an increase in the bond strength of amalgam. The Type VII glass ionomer showed the highest bond strength in comparison with the other glass ionomers.

Conclusions:

Conventional glass ionomer bonds to amalgam and shows a beneficial increase in the bond strength of the restoration in comparison with unbonded amalgam.

Remineralization of early enamel lesions using casein phosphopeptide amorphous calcium Phosphate: an ex-vivo study

Objective:

This study aimed at qualitatively evaluating the remineralization potential of casein phosphopeptide amorphous calcium phosphate on artificial early enamel lesions in an ex-vivo scenario by observing the treated tooth surface using a scanning electron microscope (SEM).

Materials and Methods:

This randomized study was conducted on 10 subjects undergoing orthodontic treatment with premolar extraction as part of their treatment. Artificial white lesions were created with the application of 37% phosphoric acid for 20 mins. Teeth were then divided into two groups: one experimental and the other control. Customised orthodontic band with a window was luted with intermediate restorative material in the experimental group whereas in the control group, band without a window was luted. The casein phosphopeptide amorphous calcium phosphate (GC TOOTH MOUSSE) paste was then applied on the window region of the experimental group for 3 mins thrice daily after meals for 14 days, whereas no paste was applied in the control group. After 14 days, teeth were extracted and viewed under an SEM.

Results:

The study groups showed remineralization of the lesions as compared with the control group in most of the samples.

Conclusion:

Casein phophopeptide could significantly remineralize the artificial enamel lesions in vivo.

Shear bond strengths of two dentin bonding agents with two desensitizers: An in vitro study

AIM

The aim of this in vitro study was to compare the shear bond strengths of two different dentin bonding agents with two different desensitizers.

MATERIALS AND METHODS

Eighty molars were taken which were ground to expose the dentin. The teeth were divided into two major groups. Each major group was subdivided into four subgroups of 10 samples each. Groups Ia and IIa were treated as dry bonding groups, groups Ib and IIb were treated as a moist bonding groups, groups Ic and IIc were rewetted with Gluma desensitizer, and groups Id and IId were rewetted with vivasens desensitizer. Major group I was treated with Gluma comfort bond and Charisma. Major group II was treated Prime and Bond NT and TPH. The samples were thermo cycled and shear bond test was performed using an Instron machine. The data were analyzed using one-way analysis of variance and Tukey's Honestly significant different test.

RESULTS

The results revealed that the specimens rewetted with Gluma desensitizer showed the highest shear bond strength compared to all other groups, irrespective of the bonding agent or composite resin used.

CONCLUSIONS

It can be concluded that rewetting with desensitizer provided better bond strength than the other groups.

Evaluation of the effect of surface moisture on dentinal tensile bond strength to dentine adhesive: An in vitro study

Aim:

To evaluate the effect of surface moisture on dentinal tensile bond strength.

Materials and Methods:

Forty freshly extracted caries free, unrestored human mandibular molars were selected. The occlusal surfaces of each tooth were ground to prepare flat dentin surfaces at a depth of 1.5 mm. Following acid etching with 37% phosphoric acid for 15 sec, they were randomly grouped, with ten specimens in each: Group I – Over wet, Group II – Blot dry, Group III- One second dry, Group IV- Over dry. Each group was treated with a single bond adhesive system (3M ESPE) as per manufacturer’s instructions. Blocks or cylinders of composite resin were built up using Teflon mould and cured. Tensile bond strengths were tested using Instron universal testing machine. The results were statistically analyzed.

Results:

The mean tensile bond strength values of group II, Blot dry was highest and statistically significant (P<0.001).

Conclusion:

After acid etching and rinsing blot drying provided consistently better bond strength.

Comparison of temperature rise in the pulp chamber with different light curing units: An in-vitro study

Aims/Objectives:

This in vitro study was designed to measure and compare the temperature rise in the pulp chamber with different light curing units.

Materials and Methods:

The study was done in two settings-in-vitro and in-vivo simulation. In in-vitro setting, 3mm and 6mm acrylic spacers with 4mm tip diameter thermocouple was used and six groups were formed according to the light curing source- 3 Quartz-Tungsten-Halogen (QTH) units and 3 Light-Emitting-Diode (LED) units. For the LED units, three modes of curing like pulse-cure mode, fast mode and ramp mode were used. For in-vivo simulation, 12 caries free human third molar tooth with fused root were used. K-type thermocouple with 1 mm tip diameter was used. Occlusal cavity was prepared, etched, rinsed with water and blot dried; bonding agent was applied and incremental curing of composite was done. Thermal emission for each light curing agent was noted.

Results:

Temperature rise was very minimal in LED light cure units than in QTH light cure units in both the settings. Temperature rise was minimal at 6mm distance when compared to 3 mm distance. Among the various modes, fast mode produces the less temperature rise. Temperature rise in all the light curing units was well within the normal range of pulpal physiology.

Conclusion:

Temperature rise caused due to light curing units does not result in irreversible pulpal damage.

Calibration of phoswich-based lung counting system using realistic chest phantom

A phoswich detector, housed inside a low background steel room, coupled with a state-of-art pulse shape discrimination (PSD) electronics is recently established at Radiological Safety Division of IGCAR for in vivo monitoring of actinides. The various parameters of PSD electronics were optimised to achieve efficient background reduction in low-energy regions. The PSD with optimised parameters has reduced steel room background from 9.5 to 0.28 cps in the 17 keV region and 5.8 to 0.3 cps in the 60 keV region. The Figure of Merit for the timing spectrum of the system is 3.0. The true signal loss due to PSD was found to be less than 2 %. The phoswich system was calibrated with Lawrence Livermore National Laboratory realistic chest phantom loaded with (241)Am activity tagged lung set. Calibration factors for varying chest wall composition and chest wall thickness in terms of muscle equivalent chest wall thickness were established. (241)Am activity in the JAERI phantom which was received as a part of IAEA inter-comparison exercise was estimated. This paper presents the optimisation of PSD electronics and the salient results of the calibration.

Preliminary results on bubble detector as personal neutron dosemeter

The bubble detector is demonstrated as one of the best suitable neutron detectors for neutron dose rate measurements in the presence of high-intense gamma fields. Immobilisation of a volatile liquid in a superheated state and achieving uniform distribution of tiny superheated droplets were a practical challenge. A compact and reusable bubble detector with high neutron sensitivity has been developed at the Indira Gandhi Centre for Atomic Research by immobilising the superheated droplets in a suitable polymer matrix. Two types of bubble detectors have been successfully developed, one by incorporating isobutane for measuring fast neutron and another by incorporating Freon-12 for both fast and thermal neutron. The performance of the detector has been tested using 5 Ci Am-Be neutron source and the results are described.

Silkworm Rearing by Rural Women in Karnataka

Silkworm rearing is an important source of livelihood for rural women in Karnataka, South India. It means financial security, increased socioeconomic status, increased control over decision-making and the opportunity to save and spend. The women are self-employed, carry out silkworm rearing in the vicinity of or in their own homesteads with a known peer group, which helps them to balance both household and economic activity. Recognition of rural women as major contributors towards silk production and improvement of service delivery to them is the need of the hour.

Comparative evaluation of the surface tension and the pH of calcium hydroxide mixed with five different vehicles: an in vitro study

AIM

The aim of this study was to evaluate the surface tension and pH of five different vehicles that are used as potential agents to mix calcium hydroxide in root canal treatments and to compare them with the final surface tension and pH of calcium hydroxide mixed with these vehicles.

MATERIALS AND METHODS

The study was carried out in two phases. In Phase I, the surface tension and pH of five vehicles (distilled water, saline, anesthetic solution, chlorhexidine, and glycerin) were evaluated using a Du Nuoy Tensiometer and a pH Meter. In Phase II, a predetermined amount of calcium hydroxide was mixed with the individual vehicles and the surface tension and pH was determined. In each group, seven samples were evaluated.

RESULTS

Among the individual vehicles, chlorhexidine had the least surface tension values (39.8+1.1 dynes/cm). Among the various calcium hydroxide mixtures, calcium hydroxide with chlorhexidine showed the least surface tension values (36.4+1.1 dynes/cm). All the vehicles showed an acidic pH ranging from 5 to 6.5. There was a significant increase in the pH values with the addition of calcium hydroxide to the respective vehicles. The calcium hydroxide mixtures had an alkaline pH ranging from 9 to 11.5; the highest pH was observed for calcium hydroxide mixed with distilled water and saline (11.5+0.2).

CONCLUSION

The surface tension and pH of the vehicles directly influenced the surface tension and pH of the calcium hydroxide mixtures. Chlorhexidine was found to be a better vehicle for calcium hydroxide when used as an intracanal medicament.

Effect of glass-ionomer cement as an intra-canal barrier in post space prepared teeth: An in vitro study

Aim:

To evaluate the bacterial microleakage across remaining Gutta-percha in teeth prepared for post space with and without the use of an intracanal glass ionomer barrier.

Materials and Methods:

Forty freshly extracted intact human mandibular premolars with single canal were instrumented, obturated with Gutta-percha and AH plus sealer and post spaces were created. Teeth were assigned into experimental groups as follows: Group I – 3 mm of Gutta-percha, Group II – 4 mm of Gutta-percha, Group III – 3 mm of Gutta-percha with 1 mm of Vitrebond as barrier, Group IV – 4 mm of Gutta-percha with 1mm of Vitrebond as barrier. The roots were suspended in Rogosa SL broth and 50 μl of lyophilized Lactobacilli Casei was inoculated as the microbial marker. The mean days taken for the broth to turn turbid were tabulated. The values were statistically analyzed using one way ANOVA and Tukey's HSD test.

Results:

At the end of 64 days, the mean and standard deviation of the number of days for the broth to turn turbid was: Group I – 20.50, (SD - 3.96). Group II – 25.43, (SD - 4.83), Group III – 38.63, (SD - 9.36), and Group IV – 53.50, (SD - 11.15)

Conclusion:

Vitrebond could be used as an intracanal barrier to provide a superior coronal seal in teeth requiring post and core.

Canal complexity of a mandibular first molar

The endodontic treatment of a mandibular molar with aberrant canal configuration can be diagnostically and technically challenging. This case report presents the treatment of a mandibular first molar with five root canals, of which three were located in the mesial root. A third canal was found between the mesiobuccal and mesiolingual root canals. The morphological pattern of separate apical terminations of three mesial root canals with separate orifices, as manifested in this case, is a rare one.

Anatomical variations of mandibular premolars in Chennai population

AIM

To analyse the prevalence of anatomical variations of mandibular premolars in Chennai population.

METHODOLOGY

It was observed, during the routine treatment of mandibular premolars that aberrations were becoming common. This necessitated an encompassing study on 500 patients, evaluating the occurrence of these aberrations. The parameters of this study included sex predilection, unilateral/ bilateral occurrences, and comparison of the incidence of anatomical variations in mandibular first and second premolar canal configuration. The study pattern was designed to observe these premolars using Radiovisiography (RVG) in different angulations to highlight the anatomical aberrations. The results were subjected to statistical analysis, which were performed using SPSS (Statistical Package for Social Science) statistical program version 10.0.5. Descriptive statistics were computed for all the variables.

RESULT

The present study revealed high incidence of anatomical aberrations in mandibular premolars among Chennai population. Out of the 500 patients studied, 123 patients [24.6%] showed anatomical variance in the canal configuration. There was high incidence of Vertucci's Type IV canal configuration as compared to Type V, Type II and Type VIII in the descending order of occurrence.

CONCLUSION

Within the limitations of this in-vivo study, it was inferred that the incidence of aberrations in the canal configuration of mandibular premolars is common and due considerations are to be given during endodontic intervention.

Hypokalemic paralysis in pregnancy

Hypokalemic paralysis is an uncommon entity with varied etiology. Renal tubular acidosis is an unusual cause of this disorder. Its occurrence with pregnancy is rare. We report such a case and mention the implications of the association and review relevant literature breifly.

Role of prolactin in human milk composition and serum lipids studied during suppression of galactorrhea with bromocriptine

Bromocriptine suppressed lactation by depressing the serum prolactin (PRL) level in 10 of 12 cases with profuse galactorrhea. The PRL level in galactorrhea milk was lower than in serum and was similar to that obtained in normal mature milk. However, significantly higher total solid, total ash, lipid and calcium levels, and reduced lactose and potassium levels were seen in galactorrhea specimens compared to mature milk. Although all the constituents decreased during treatment, the highly significant reduction in lipid and calcium levels shows the predominant effect of PRL on mammary synthesis and/or transport of these constituents. Fasting serum total lipids, total cholesterol and triglyceride levels were significantly higher in the galactorrhea group than in breast-feeding women with established lactation, suggesting that elevated serum PRL plays a role in lipid metabolism.

Lipophilic O-antigens in Rhodospirillum tenue

Lipopolysaccharides of eight wild-type strains of the phototrophic bacterium Rhodospirillum tenue have been analyzed. All of the lipopolysaccharides are highly lipophilic. The compositions of preparations obtained by the phenol-water or by the phenol-chloroform-petroleum ether procedure are very similar. The polysaccharide moiety, obtained by mild acid hydrolysis of lipopolysaccharide, consists mainly of aldoheptoses: L-glycero-D-mannoheptose is present in all strains, whereas D-glycero-D-mannoheptose is an additional constituent in some strains. Galactosaminuronic acid and two unknown ninhydrin-positive components were detected in the lipopolysaccharides of six strains. Spermidine and putrescine are present in large amounts in a salt-like linkage in the lipopolysaccharides from three strains. 2-Keto-3-deoxyoctonate forms the linkage between the polysaccharide moiety and lipid A. The lipid A fraction contains all the glucosamine and all the D-arabinose present in the lipopolysaccharide. D-Arabinose is an invariable constituent of the lipid A from the Rhodopseudomonas tenue lipopolysaccharides investigated. The principal fatty acids are beta-hydroxycapric, myristic, and palmitic acids. The isolated R. tenue lipopolysaccharides (O-antigens) react with rabbit antisera prepared against homologous cells. The titers in passive hemagglutination are low, similar to those found with enterobacterial R-lipopolysaccharides. R. tenue O-antigens containing only L-glycero-D-mannoheptose and those containing both the L- and D-epimers of glycero-D-mannoheptose could not be differentiated by serological means.