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This study aimed to determine the effects of three different varnish materials (containing casein phosphopeptide-amorphous calcium phosphate, nano-hydroxyapatite, and fluoride) on enamel. Thirty-three extracted human third molars were used for specimen preparation. These were demineralized using phosphoric acid. Three experimental groups (n = 11) were treated with 3M™ Clinpro™ White Varnish, MI Varnish®, and Megasonex® toothpaste, respectively, every twenty-four hours for fourteen days. Analysis of the microhardness of the specimens’ enamel surfaces was carried out via the Vickers method, and by scanning electron microscopy/energy dispersive X-ray spectroscopy (SEM/EDS). Analysis was performed at three stages: at baseline value, after demineralization, and after the period of remineralization. Data were subjected to Scheffe’s post hoc test. The mean microhardness values (HV0.1) obtained for the group of samples treated with MI Varnish® were higher compared with the other two groups (p = 0.001 for both comparisons), while the first and third groups did not differ significantly from each other (p = 0.97). SEM analysis showed uneven patterns and porosities on all samples tested. EDS results showed an increase in the mineral content of the examined samples, with the highest mineral content observed in the MI Varnish® group. It can be concluded that MI Varnish® use has a better remineralization effect on enamel than the other two materials.

U dugogodišnjoj kliničkoj primjeni titanija sve se više uočavaju štetni učinci kao što je otpuštanje iona Ti4+ uslijed neprihvatljivog biokorozijskog ponašanja. Magnezij se u posljednje vrijeme često primjenjuje u biointeraktivnim konceptima oseointegracijskih površina kao značajan čimbenik oseointegracije u biodegradacijskom procesu otpuštanja iona Mg2+. Kako se titanij i magnezij ne mogu legirati, metalurgija praha smatra se tehnikom izbora za proizvodnju titanij-magnezijeva kompozitnoga materijala. Svrha ovog rada je istraživanje biokorozijskih svojstava titanij-magnezijeva materijala kroz proučavanje otpuštanja iona Ti4+ i Mg2+ te promatranje promjena nastalih na površini. Pripravljene su tri vrste materijala, s 1, 2 i 5 % magnezija u titanijskoj osnovi. Kao kontrolna skupina upotrijebljen je komercijalno čisti titanij stupnja 4. Za otpuštanje iona Ti4+ i Mg2+ korišten je test uranjanja u četiri vrste otopina: umjetnoj slini, umjetnoj slini s pH 4 i s dodanim fluorom te Hankovoj otopini koje su zatim analizirane metodom masene spektrometrije induktivno spregnutom plazmom. Površine uzoraka karakterizirane su skenirajućom elektronskom mikroskopijom, energijskom disperzivnom spektroskopijom, rendgenskom difrakcijskom analizom te profilometrijskim određivanjem hrapavosti površine. Rezultati istraživanja pokazali su značajno manje otpuštanje iona Ti4+ u usporedbi s kontrolnom skupinom. Dok su na otpuštanje iona Ti4+ statistički značajan utjecaj imale vrste otopina, otpuštanje iona Mg2+ bilo je pod utjecajem vrste ispitivanog materijala. Na površinama je uočena intenzivnija fizikalno kemijska aktivnost ispitivanog materijala koja sugerira na zaključak o potencijalnoj biointeraktivnosti istog. Istovremeno, magnezijeva korozija se je u nekim uvjetima pokazala neprihvatljivom za primjenu in vivo. Stoga su potrebna daljnja istraživanja strukture i sastava inovativnog titanij-magnezijeva kompozitnoga materijala proizvedenog tehnikom metalurgije praha. Introduction: Titanium and its alloys have been widely used as an implantable alloplastic biomaterial in the field of dental medicine for the last half century. Good mechanical properties, favourable corrosion behaviour and excellent biocompatibility are mentioned as the main reasons for such a large clinical application. The important bio-corrosive characteristic of titanium is the formation of dioxide layer of TiO2 which protects the metal of dissolving. However, such a surface layer plays poor protective role in some environmental conditions such are low pH value of the medium and the presence of fluorides. Magnesium enhances osteoinduction, osteoconduction and osseointegration of implantable biomaterial by promoting some osteogenic processes in the alveolar bone during a peri-implant bone formation. However, magnesium, as a pure metal, demonstrates poor bio-corrosive behaviour resulting in the gaseous H2 evolution and the alkalization of surrounding area. The powder metallurgy technique has been shown as the method of choice to unify the positive properties of two metals. In that way produced titanium-magnesium composite material could demonstrate better corrosive behaviour and develop an innovative and biomimetic surface characteristics in order to improve the process of osseointegration of such an implantable material. Aim: The aim of this study is to investigate the bio-corrosive characteristics of titanium-magnesium composite by determining the amount of released titanium and magnesium ions and by observing the surface changes during the corrosion test in simulated body fluids. Materials and methods: Three groups of innovative titanium-magnesium composite were produced by means of powder metallurgy technique: 1 mass%, 2 mass% and 5 mass% of magnesium in titanium matrix. Commercially pure titanium was used as a control group. The standardized static immersion test was used to carry out the bio-corrosion testing. Artificial saliva, artificial saliva with pH 4, artificial saliva with fluorides added and Hank’s balanced salt solution were prepared. The amount of released titanium and magnesium ions in the solution were determined by means of inductively coupled plasma mass spectrometry. The surface topography was observed by means of scanning electron microscopy, energy dispersive spectroscopy and X-ray diffraction analysis. To compare the surface roughness before and after the immersion, profilometry method was emloyed. Statistical evaluation was done by Statistica 7.0 software package. Significance level in all tests was set to p