School of Dental Medicine, University of Zagreb, Croatian Dental Society - Croatian Medical Association
Abstract
Svrha: U uvjetima in vitro željelo se procijeniti utječe li i kako primjena 20-postotnog natrijeva askorbata na deproteinizirani dentin, a za to se rabio elektronski mikroskop/rendgenska spektroskopija
raspršivanja energije (SEM/EDS). Materijal i metode: Sedam ekstrahiranih humanih trećih kutnjaka odabrano je za istodobnu analizu sastava i dentinske površine uz pomoć SEM/EDS-a. Bilo je odabrano i poduzeto sljedeće: G1 – zdrav dentinski supsrat; G2 – demineralizirani dentinski supstrat demineraliziran 15 sekundi 37-postotnom ortofosfornom kiselinom prema uputi proizvođača; G3 – deproteinizirani dentinski supstrat deproteiniziran 60 sekundi uz neprekidno miješanje u 10-postotnoj vodenoj otopini natrijeva hipoklorida; G4, G5, G6 i G7 – demineralizirani i deproteinizirani dentinski supstrat primjenom 10-postotne vodene otopine natrijeva
askorbata tijekom 15, 30, 60 sekundi te jednu minutu prema redoslijedu navedenih grupa. Uzorci su pregledani elektronskim mikroskopom (Quanta 2000 – Fei Company) opremljenim spektrometrom raspršujuće energije i naponom ubrzanja od 10 KV pri povećanju od 2000 X u vakuumu. Rezultati: Analiza SEM/EDS-om pokazala je progresivno odlaganje kristala natrijeva askorbata usporedno s povećanjem antioksidacijskog sredstva, stvarajući koru koja može prouzročiti zatvaranje pojedinih dentinskih tubula. Nije bilo statistički značajne razlike između G2 i G3 (p>0,05). Primjena 10-postotnog natrijva askorbata 60 sekundi smanjila je razinu kisika (P=0,029), magnezija (P=0,019) i natrija (P=0,029). Zaključak: Nakon primjene 10-postotnog natrijeva askorbata, progresivno se talože njegovi kristali i stvaraju koru na dentinskom supstratu koja začepljuje pojedine dentinske kanaliće.Objective: To evaluate in vitro the influence of application time of sodium ascorbate to 10% on the deproteinized by scanning electron microscopy/energy dispersive x-ray spectroscopy (SEM/EDS). Methods: Seven extracted human third molars were selected. For analysis of the composition of the dentin surface by SEM/EDS, 7 samples were analyzed simultaneously as follows: G1: Healthy dentin
substrate, G2: Demineralized dentin substrate with 37% phosphoric acid for 15 s (demineralization), strictly following the manufacturer’s recommendations, G3: Deproteinized dentin substrate after demineralization, 10% sodium hypochlorite aqueous solution for 60 s under constant agitation (deproteinization), G4, G5, G6 and G7: demineralized, deproteinized dentin substrate after application of 10% sodium ascorbate for 15 s, 30 s, 60 s, 10 min, respectively. The samples were examined by a scanning electron microscope (Quanta 2000 - Fei Company) equipped with an energy dispersive spectrometer with acceleration voltage 10 KV at ×2,000 magnification under vacuum. Results: The SEM/EDS analysis showed progressive deposition of sodium ascorbate crystals as the application time of the antioxidant agent increased, forming crusts which can cause occlusion of some dentinal tubules. There was no statistically significant difference between G2 and G3 (P>0.05). However, the application of 10% sodium ascorbate for 60 s resulted in a decrease in the oxygen (P=0.029), magnesium (P=0.019) and sodium (P=0.029) levels. Conclusion: After application of 10% sodium ascorbate, deposition of sodium ascorbate crystals occurred progressively forming crusts on dentin substrate, which causes occlusion of some dentinal tubules
