Evaluation of glassionomer cement application for permanent binding of prosthetic dentures

Fixed dentures are created in order to rehabilitate the function of orofacial system, to correct disordered interdental relation, as well as the relation between jaws and to do esthetic correction. Binding of fixed dentures to the teeth carriers is done with a layer of binding biomaterials from the group of dental cements. Cement as the choice of dental biomaterials has to be the best cement for the most frequent, routine management for these type of works and most frequently used materials – metal, acrylate, ceramics. Cement must be safe to use with patients. Ideally, it must have longtime advantages such as to be for various uses, to find the right balance between results and simplicity of application, which are the most important for routine management. There are many types of cement. In this study, Zn-phosphate and glassionomer cement were used. In modern dental technology, production of cement is well developed and the most concerns are about non-toxicity, biocompatibility, bioinertion, biofunction. In some cases acidic balance disorder of saliva medium can bring to release of low doses of heavy metal ions after the reaction of cement and heavy metal ions from dental compounds. In this study, the best results were achieved with glassionomer cement, because the lowest percent of released heavy metal ions in saliva medium was noticed after cementing of fixed dentures by glassionomer cement. Because of its characteristics, glassionomer cement can be the choice material for permanent cementing of fixed prosthetic dentures

Application analysis of micro and nano composites in restoring of bone tissue of the jaw

Application of synthetic polymer biomaterials is very often used in biomedicine and dentistry. That’s why the need for creating the new polymer biomaterials is more and more obvious. Hydroxy-apatite, as a natural constituent of bone, has been already used for many years in all segments of dentistry. In order to develop better properties, hydroxy-apatite is combined with polymers. In this research, application of micro and nano composite biomaterials in reconstruction of osteoporosis damaged alveolar bone of rats is analyzed. Evaluation of regeneration of restored osteoporosis damaged alveolar bone of rats was done by histopathological analyses. The optimal results were after 24 weeks after implantation of calcium-phosphate/poly-D, L-lactide-co-glycolide (CP/DLPLG) composite biomaterials nano particles in comparison to micro particles. Regeneration and reparation of damaged alveolar bone with creation of new bone tissue which is very similar to mature bone, are much better on the place of nano CP/DLPLG implantation. Because of its very good osteoconductive effect, applied nano CP/DLPLG composite can totally renew lost bone tissue, so it can be the material of choice for the alveolar bone defect rehabilitation

Effect of variable frequency electromagnetic field on deposit formation in installations with geothermal water in Sijarinjska spa (Serbia)

In this paper we have examined the effect of variable frequency electromagnetic field generated with a homemade device on deposit formation in installations with geothermal water from Sijarinjska Spa. The frequency alteration of the electromagnetic field in time was made by means of the sinusoidal and saw-tooth function. In laboratory conditions, with the flow of geothermal water at 0.015 l/s and temperature of 60 °C for 6 hours through a zig-zag glass pipe, a multiple decrease of total deposit has been achieved. By applying the saw-tooth and sinusoidal function, the decrease in contents of calcium and deposit has been achieved by 8 and 6 times, respectively. A device was also used on geothermal water installation in Sijarinjska Spa (Serbia), with the water flow through a 1'' diameter non-magnetic prochrome pipe at 0.15 l/s and temperature of 75 °C in a ten-day period. A significant decrease in total deposit and calcium in the deposit has also been achieved

The role of synthetic biomaterials in resorptive alveolar bone regeneration

Gubitak koštanog tkiva, usled resorpcije viličnih kostiju, ima značajno mesto u stomatologiji. U cilju rešavanja problema deficita koštanog tkiva nastalih resorpcijom alveolarne kosti pristupilo se primeni sintetičkih materijala na bazi CP/PLGA (kalcijum-fosfat/polilaktid-co-glikolid) kompozita. Istraživanja su radena na pacovima kod kojih je arteficijelno izazivana resorpcija viličnih kostiju. Rezultati su pokazali da se najbolji efekat regeneracije alveolarne kosti postižu implantacijom nanokompozita. Efekat nanokompozita praćenje određivanjem sadržaja kalcijuma i fosfata, kao osnova kristalne rešetke hidroksiapatita. Dobijeni rezultati pokazuju da sintetički CP/PLGA nanokompozit olakšava rehabilitaciju oslabljene alveolarne kosti, pa zahvaljujući svom osteokonduktivnom efektu može u budućnosti biti materijal izbora u zameni koštanog tkiva.The alveolar bone tissue resorption defect has a significant role in dentistry. Because of the bone tissue deficit developed by alveolar resorption, the use of synthetic material CP/PLGA (calcium-phosphate/polylactide-co-gliycolide) composite was introduced. Investigations were performed on rats with artificially produced resorption of the mandibular bone. The results show that the best effect on alveolar bone were attained by using nano-composite implants. The effect of the nanocomposite was ascertained by determining the calcium and phosphate content, as a basis of the hydroxyapatite structure. The results show that synthetic CP/PLGA nanocomposite alleviate the rehabilitation of weakened alveolar bone. Due to its osteoconductive effect, CP/PLGA can be the material of choice for bone substitution in the future

Treatment of osteoporosis alveolar bone with cobalt substituted hydroxyapatite nanoparticles

In this study nanocomposite was used for reconstruction of alveolar bone defect of mandible. Specifically, the main interest for the use of magnetic nanoparticles in biomedical applications is that an inhomogeneous external magnetic field exerts a force on them, and thus they can be manipulated or transported to a specific diseased tissue by a magnetic field gradient. In addition, magnetic particles are of interest because they do not retain any magnetism after removal of the magnetic field. Specifically, inorganic biodegradable nanoparticles (including ceramics, like hydroxyapatite) will be functionalized with bioactive compounds that bond to bone of low mass. Extremely good results in the recovery of alveolar bone osteoporosis were achieved already after 6th week of the application of magnetic nanoparticles. After bonding specifically to osteoporotic bone and not healthy bone, magnetic nanoparticle systems will deliver bioactive compounds to locally increase bone mass. Implantation of magnetic nanoparticles will create bone construction and enable quick formation of new bone and become the material of choice for accelerated bone regeneration

Određivanje antioksidativnog kapaciteta uzoraka kakao praha, crne i mliječne čokolade pomoću cikličke voltametrije: korelacija s rezultatima spektrofotometrijskog ispitivanja i udjelima pojedinačnih fenolnih spojeva

Phenolic antioxidants in cocoa powder, dark chocolate and milk chocolate samples are quantified electrochemically using cyclic voltammetry with a glassy carbon electrode. Cyclic voltammograms were recorded from 0 to 800 mV at a scan rate of 100 mV/s. Phenolics with an ortho-diphenol group show the first oxidation peak in the potential range between 370 and 460 mV (vs. Ag/AgCl) in 0.1 mol/L of the acetate buffer, pH=4. The first and third anodic current peaks, close to 670 mV, can be ascribed to the first and second oxidation of the catechin-type flavonoids that are present at a high concentration in samples. The second peak at around 560 mV can be ascribed to phenolic acids. Procyanidins B1, B2, B3 and B4 did not have any visible waves. Strong positive correlation was established between antioxidant activities deduced from cyclic voltammograms with those determined using spectrophotometric assays. HPLC method was used for the quantification of individual phenolic compounds.Fenolni su antioksidansi u uzorcima kakao praha, tamne i mliječne čokolade elektrokemijski određeni pomoću cikličke voltametrije, primjenom elektrode od staklastog ugljika. Ciklički su voltamogrami snimljeni u rasponu od 0 do 800 mV, pri brzini skeniranja od 100 mV/s. Fenolni su spojevi s orto-difenilnom grupom dali prvi oksidacijski pik pri potencijalu između 370 i 460 mV (u usporedbi s referentnom elektrodom Ag/AgCl) u acetatnom puferu koncentracije od 0,1 mol/L, pH=4. Prvi i treći anodni pikovi, dobiveni pri otprilike 670 mV, potječu od prve i druge oksidacije katehina, prisutnih u većim udjelima u ispitivanim uzorcima. Drugi pik, dobiven pri otprilike 560 mV, potječe od fenolnih kiselina. Procijanidini B1, B2, B3 i B4 nisu dali vidljive pikove. Utvrđena je jaka pozitivna korelacija između antioksidativne aktivnosti određene cikličkom voltametrijom i one određene spektrofotometrijom. Za određivanje udjela pojedinačnih fenolnih spojeva upotrijebljena je metoda HPLC

The role of synthetic biomaterials in resorptive alveolar bone regeneration

The alveolar bone tissue resorption defect has a significant role in dentistry. Because of the bone tissue deficit developed by alveolar resorption, the use of synthetic material CP/PLGA (calcium-phosphate/polylactide-co-gliycolide) composite was introduced. Investigations were performed on rats with artificially produced resorption of the mandibular bone. The results show that the best effect on alveolar bone were attained by using nano-composite implants. The effect of the nanocomposite was ascertained by determining the calcium and phosphate content, as a basis of the hydroxyapatite structure. The results show that synthetic CP/PLGA nanocomposite alleviate the rehabilitation of weakened alveolar bone. Due to its osteoconductive effect, CP/PLGA can be the material of choice for bone substitution in the future

Migration of fluoride ions from the permanent teeth into saliva in children with glass ionomer cement restorations: An in vitro study

Bacground/Aim. Glass ionomer cements (GIC) belong to the group of polycarboxyl cements, and one of the principal characteristics of these materials is their anticariogenic potential of fluorine release into saliva and enamel-dentin substance. The aim of this study was to examine the content of released fluorine from GIC restorations (Fuji IX, GC, Japan) of young permanent teeth in the medium of artificial saliva and similar releases in the same medium by the restorations of these teeth treated with a low concentration fluoride solution. Methods. We examined 12 premolars exctracted from orthodontic reasons. The GIC restored teeth were divided into the group treated daily with low concentration fluoride solution (334 ppm) and the control, not treated group. The samples of artificial saliva were analyzed for fluorine ion content using an ion selective electrode. Results. Our comparative analysis of the mean values using the Student’s t-test demonstrated a statistically significant difference in fluorine ion concentration in artificial saliva of fluoridated and non-fluoridated teeth with GIC fillings after 14 and 21 days (p < 0.05), while the difference detected after 7 days was with no statistical significance. Conclusion. The results of this in vitro study indicated that low-concentration fluoride solutions could serve to refluoridate GIC fillings and contribute to an increased fluorine content in saliva. The process of refluoridation of GIC fillings should be advised 2-3 weeks after the restoration, since the release of fluorine from GIC fillings diminishes in time